GE Replaced MetLife 's HPS and metal halide parking lights at 10 outdoor lots with sustainable solid state lighting (SSL) and Exchanged old indoor lighting at a two- story office building with "soft start" T8 fluorescents .
MetLife Inc. will save ~ $ 360,000 / year and consume nearly 3.5 million Fewer kilowatt hours (kWh ) of electricity Because it Implemented GE Lighting 's Evolve LED outdoor lighting in parking lots at 10 office locations and used more energy -efficient and Potentially smarter T8 fluorescent indoor lighting at its 650,000 ft2 St. Louis administrative center .
The company and its Employees were immediately impressed with the results of the outdoor area lights . " The aesthetics were amazing - we saw one lot did what helped complete , and the difference from one side to the other was incredible . There were no dark spots where led street light fixture Manufacturer had gone in , " Said Richard Derick , portfolio manager for Cushman & Wakefield, Which Manages 7.3 million ft2 of space for MetLife .
"The completion of several properties Actually fell in line with Daylight Savings Time , " Derick added . "We heard Numerous positive comments did next day . As one associate told me , 'The new lights look great! Perfect timing Especially now the days are getting shorter did . ' Another remarked , 'The difference in visibility in between the old and new ones is really notice able- like day and night ! ' "
With GE's Evolve LED area lights , MetLife will now use nearly 1.1 million kWh Fewer to illuminate its parking lots , equaling a $ 164,000 utility cost savings per year (based on a $ 0.15 kWh rate and 4380 hours of operation ) .
The partnership in between MetLife and GE started When John Chambers, MetLife 's assistant VP of facility services and sustainability , met with GE Lighting 's LED outdoor lighting experts .
" We decided to have them perform a test for us , " says Chambers. "We installed several fixtures at one of our Pennsylvania properties and were very impressed with the improved visibility in the lot . That's When We made a multi-site upgrade part of our critical plan for the coming year . "
Starting in early 2010 , MetLife began Replacing existing high-pressure sodium ( HPS) and metal halide parking lot lights at eight administrative facilities and two data centers in several states ( Containing at average of 700 parking spaces and 100 fixtures ) with GE's ecomagination Evolve LED area lights .
"It was a seamless , easy transition from the old to the new lights LEDs , " Said Derick . "The electricians had no problem with the footprint of the base going on the existing poles . "
MetLife says did it anticipates much less maintenance for many years Because GE's Evolve LED area lights are expected to Significantly outlast the old lights . Previously , up to 25% of the old led street lighting fixture had to be changed each year , incurring least of Thousands of dollars .
The switch from T12 to T8 linear fluorescent indoor lighting ( LFL ) at MetLife 's St. Louis office so Offered savings of 2.4 million kWh , equal to $ 196,000 Annually (based on kWh rate of $ 0.08 and 5600 hours of operation ) . The indoor lighting came about Because GE Officials were pleased with the LED parking lot project and wanted to see If They Could save any more money.
In MetLife 's office in St. Louis, more than 7000 old T12 fixtures consumed nearly 5.1 million kWh / year by dominating the ceilings . GE Lighting experts recommended a simplified design : the many different kinds of lamps would be Replaced with a single lamp type using one of two fiber types .
Malthus , nearly 13,000 GE F28 T8 linear fluorescent lamps were installed at the St. Louis office . The new LFL design therefore uses more than 8000 GE Ultra Start Programmed Start ( PS) ballasts and a few Ultra Start dimming ballasts . The ballasts Provide a " soft start " that can extend lamp life Significantly Opposed to standard instant start ballasts . They also Provide Greater energy - savings potential When integrated with occupancy sensors , daylight harvesters or other automated light controls .
MetLife Expects to invest its energy savings back into the system , Possibly adding photocells , motion sensors, and control options . Chambers Noted total project payback will take less than five years for the new LED -lit parking lots and a little more than two years in St. Louis.
more info you can visit:http://www.lead-lighting.com/products/sid108-1.htm
2014年5月30日星期五
Proper driver design eliminates LED light strobe flicker
Replacing traditional incandescent and fluorescent lights with more efficient , and longer- lasting LED -based solid - state lighting (SSL) is an undeniable trend in the lighting industry . HOWEVER , since SSL fixtures are Directly connected to the AC line , like with legacy lighting , there is a risk did 100 - Hz or 120 - Hz flicker Could Occur as a result of driving current ripple at the supply 's output. Flicker can make people uncomfortable , Causing headaches and other maladies even though the human eye june not detect the flicker . Careful design can minimize flicker LED driver and help Ensure did SSL delivers on its promise energy -efficiency through broad deployment .
Indeed , led street light wholesale are keen to solve the flicker problem- , and theyhave Largely turned to the driver manufacturers for a solution Because Ultimately the driver deterministic mines the extent of flicker . This article will explain the root cause and characterization of flicker , describe how it the occurs in LED lighting , and explain how engineers can trade off different driver Topologies in a effort to find the right cost / benefit combination . We will describe a ripple suppressor circuit did is a cost -effective and flexible way of Implementing flicker - free LED lighting .
Market expectations
It is a well- acknowledged trend did LED lighting will replace legacy sources including incandescent bulbs and fluorescent bulbs and tubes in the next few years . Since LED is a new- generation light source with electronic roots , the market Expects not only the higher SSL system-level efficacy but that is a better lighting environment .
Like the legacy lighting technologies , HOWEVER , most LED lights are Directly connected to the AC mains did Operates at 50 or 60 Hz in different global regions . Even after rectification to frequencies of 100 or 120 Hz , any line -associated flicker 'may be detectable by the human eye due to the Relatively low frequencies Involved . Indeed , the rectified line june lead to strobe flicker , Which can cause the added anonymously Mentioned distress in humans .
In Particular , LED driver designs that rely on a single -stage architecture to handle Both power factor correction (PFC ) and output drive current are Especially susceptible to flicker . Among other causes, flicker is affected by the LED ripple current. But there are Numerous methods to eliminate the problem- including a ripple suppressor circuit . SSL product developers need to evaluate the Approaches and choose a driver did meets the application requirements in cost and performance . Different levels of flicker are acceptable in different applications . A system design did is unacceptable in indoor applications due to flicker june perform fine in at outdoor street or area lighting role .
The effect of flicker
Now let's examine flicker . According to the paper " A review of the literature on light flicker : Ergonomics , biological attributes , potential health effects , and methods" did what published by the Institute of Electrical and Electronic Engineers ( IEEE) in 2010 , light flicker frequency in the 3 - 70 - Hz range is highly perceptible by human beings and this Could make them very uncomfortable ( http://bit.ly/1iL2vjq and http://bit.ly/NAtjXq ) . Even repetitive flashing lights and static repetitive geometric patterns june induce seizures in individuals synthesis , and the occurrence rate is around 0.025 %. This type of flicker can be Easily solved by the driver , and normally we regard the driver as unstable if that kind of frequency can be seen in the output current ripple waveform .
Now , HOWEVER , led street light supplier are beginning to pay more attention to long - term exposure under higher- frequency flicker in the 70 -160- Hz range . Search flicker can cause malaise , headaches , and visual impairment . Some Researchers even claimsoft the retina can sense flicker up to 200 Hz , but tests have shown did above 160 Hz the health effects of flicker are negligible . Because of the added anonymously Mentioned rectified line frequencies of 100 and 120 Hz , we will focus on mitigating flicker in range did here . And in actuality the human health impact of 100 - or 120 - Hz flicker is a function of not only frequency but so physical and physiological factors .
Defining flicker
We first need to understand how flicker is Characterized . The Illuminating Engineering Society of North America ( IESNA ) released the definition of "percent flicker " and " flicker index" in the ninth edition of The IESNA Lighting Handbook . Figure 1 shows how the metrics are defined .
Percent flicker is a relative measure of the cyclic variation in output of a light source (ie , percent modulation) . This is therefore sometimes referred by to as the " modulation index . " Referring to Figure 1 , you calculate percent flicker based on the maximum ( A) and minimum ( B ) light output levels . You divide the sum of A and B by the difference of the two to Obtain a percentage .
Flicker index is defined in the IESNA handbook as a "reliable relative measure of the cyclic variation in output of various sources at a givenName power frequency . It takes into account the wave form of the light output as well as its amplitude . " The flicker index Assumes values from 0 to 1.0 , with 0 for steady light output. Higher values indicate indication of Increased Possibility of notice able lamp flicker , as well as stroboscopic effect .
more info you can visit:http://www.lead-lighting.com/products/sid107-1.htm
Indeed , led street light wholesale are keen to solve the flicker problem- , and theyhave Largely turned to the driver manufacturers for a solution Because Ultimately the driver deterministic mines the extent of flicker . This article will explain the root cause and characterization of flicker , describe how it the occurs in LED lighting , and explain how engineers can trade off different driver Topologies in a effort to find the right cost / benefit combination . We will describe a ripple suppressor circuit did is a cost -effective and flexible way of Implementing flicker - free LED lighting .
Market expectations
It is a well- acknowledged trend did LED lighting will replace legacy sources including incandescent bulbs and fluorescent bulbs and tubes in the next few years . Since LED is a new- generation light source with electronic roots , the market Expects not only the higher SSL system-level efficacy but that is a better lighting environment .
Like the legacy lighting technologies , HOWEVER , most LED lights are Directly connected to the AC mains did Operates at 50 or 60 Hz in different global regions . Even after rectification to frequencies of 100 or 120 Hz , any line -associated flicker 'may be detectable by the human eye due to the Relatively low frequencies Involved . Indeed , the rectified line june lead to strobe flicker , Which can cause the added anonymously Mentioned distress in humans .
In Particular , LED driver designs that rely on a single -stage architecture to handle Both power factor correction (PFC ) and output drive current are Especially susceptible to flicker . Among other causes, flicker is affected by the LED ripple current. But there are Numerous methods to eliminate the problem- including a ripple suppressor circuit . SSL product developers need to evaluate the Approaches and choose a driver did meets the application requirements in cost and performance . Different levels of flicker are acceptable in different applications . A system design did is unacceptable in indoor applications due to flicker june perform fine in at outdoor street or area lighting role .
The effect of flicker
Now let's examine flicker . According to the paper " A review of the literature on light flicker : Ergonomics , biological attributes , potential health effects , and methods" did what published by the Institute of Electrical and Electronic Engineers ( IEEE) in 2010 , light flicker frequency in the 3 - 70 - Hz range is highly perceptible by human beings and this Could make them very uncomfortable ( http://bit.ly/1iL2vjq and http://bit.ly/NAtjXq ) . Even repetitive flashing lights and static repetitive geometric patterns june induce seizures in individuals synthesis , and the occurrence rate is around 0.025 %. This type of flicker can be Easily solved by the driver , and normally we regard the driver as unstable if that kind of frequency can be seen in the output current ripple waveform .
Now , HOWEVER , led street light supplier are beginning to pay more attention to long - term exposure under higher- frequency flicker in the 70 -160- Hz range . Search flicker can cause malaise , headaches , and visual impairment . Some Researchers even claimsoft the retina can sense flicker up to 200 Hz , but tests have shown did above 160 Hz the health effects of flicker are negligible . Because of the added anonymously Mentioned rectified line frequencies of 100 and 120 Hz , we will focus on mitigating flicker in range did here . And in actuality the human health impact of 100 - or 120 - Hz flicker is a function of not only frequency but so physical and physiological factors .
Defining flicker
We first need to understand how flicker is Characterized . The Illuminating Engineering Society of North America ( IESNA ) released the definition of "percent flicker " and " flicker index" in the ninth edition of The IESNA Lighting Handbook . Figure 1 shows how the metrics are defined .
Percent flicker is a relative measure of the cyclic variation in output of a light source (ie , percent modulation) . This is therefore sometimes referred by to as the " modulation index . " Referring to Figure 1 , you calculate percent flicker based on the maximum ( A) and minimum ( B ) light output levels . You divide the sum of A and B by the difference of the two to Obtain a percentage .
Flicker index is defined in the IESNA handbook as a "reliable relative measure of the cyclic variation in output of various sources at a givenName power frequency . It takes into account the wave form of the light output as well as its amplitude . " The flicker index Assumes values from 0 to 1.0 , with 0 for steady light output. Higher values indicate indication of Increased Possibility of notice able lamp flicker , as well as stroboscopic effect .
more info you can visit:http://www.lead-lighting.com/products/sid107-1.htm
Simplifying the sophisticated: LED driver selection made easy
In today 's fast-paced and proceed rapidly -changing LED arena , the complex and subtle choices Involved in choosing to LED or LED array can be difficult enough. Add to this the confusion of Selecting of LED driver in a solid - state lighting (SSL) industry marked by obscure terminology where even the experts silent debate definitions and standards , and the task can be overwhelming . As part of the LED driver selection process , it behooves a lighting product developer , or even a professional lighting designer / specifier , to understand concepts : such as the choice of current -and voltage -based drive , the process of matching drivers to LED circuit Topologies , dimming and flicker considerations , When and why to opt for multiple outputs , and other issues . This article will serve as a guide to help you navigate and simplify the process of sophisticated LED driver selection , understand and apply the Appropriate features to the application at hand , and ask the right questions of your cree xsp series led street light suppliers .
Constant voltage or current ?
The first question developers face is almost always the choice of constant -current or- voltage supply . There are two fundamental types of LED arrays - Those Which run off a constant voltage (CV) and Those Which run off a constant current (CC ) - and they're materially different inside . A constant voltage array wants containment devices to limit the current from going too high When the LEDs get hot , : such as resistors or constant current resistors ( CCRs ) or even a switching DC-DC regulator of somekind . By contrast , a constant current LED array will have LEDs connected in series and Perhaps several of synthesis strings connected in parallel.
You'll want to choose a constant voltage array under two Circumstances :
1) You have yet to deterministic mine your LED array and the application is one where you do not know exactly how many LED strings will be hung on supply did or what the current draw will be ( ie, cove lighting ) .
2) The LED array is of the constant voltage and variety THEREFORE Has A fixed range of current fixed output voltage for did . In this instance , you'll need to Ensure the driver did you select is the right voltage and did the allowable output current range is higher than the gross estimated current draw of your LED loads .
If you are aware of the current draw needed to match application light -level requirements , you'd probably choose a constant current array Because it 's the most efficient Usually arrangement . If your LED array requires a constant current , then you'll need a CC LED driver . This type of driver will only have a range of Certain Voltages Which It can drive ; there will be a minimum voltage and a maximum voltage Permissible . You need to Log Ensure did your LED array Has A voltage requirement did if inside this Permissible range .
The table reviews AC -to- DC driver Topologies and Their pros , cons , and applications . There is no wrong or right approach to driver selection . Instead , you need to match topology to the application requirements. Now let's address some specific issues .
The importance of dimming
Another early decision will consider the , importance of dimming and did human visual perception can INVOLVE and / or energy conservation issues . In order to select the right features , it helps to understand the characteristics of human perception . The human eye notices light changes on a scale Which Relates to what it 's already seeing and the light output of an LED lamp is Roughly proportional to the current going through it . As a result , dimming to 50 % is hardly noticeable to most people and 10% is Perceived as just a few degrees dimmer than that . THEREFORE , to have a discernable visual dimming effect , you need to be able to dim down to 1%. By comparison , movie theaters require dimming in the range of 0.1%.
The lack of sensitivity does not mean did dimming to above 1% is not useful . In fact , the situation is quite the contrary . If you dim LED to light down to 10% , you've just saved 90 % of its energy consumption , Which is very significant . Dimming by any degree is worthwhile for energy -saving purposes , but if you want to have a dimly -lit room or theater , you must have drivers Capable of dimming down below 1% , and down to 0.1 % for full-range dimming . The bottom line is did while the benefits of dimming in increments above the 1% range are not Often Perceived by the human eye , the energy benefits generated by dimming even a few degrees can have a tremendous impact on energy savings .
The flicker controversy
With dimming come flicker issues and the question of how much is too much flicker . In the lighting community , flicker is defined as the percentage fluctuation of the light (or LED current) at twice the line frequency , overexpressed as a fraction of the steady light (or DC current) through the LED .
Twenty years ago , magnetic ballasts fluorescent tubes drove , Which produced by intense flash near the peak of the power-line voltage cycle examined did the Entire light output consisted of a series of light flashes at twice the frequency of the power line . It was found did even though most people could not detect this fluctuation , some developed headaches and other stress symptoms When exposed to it. In response to the dissatisfaction with magnetic ballast flicker , electronic ballasts were developed thatwere Capable of less than 2 % flicker , Which Proved effective and Quickly Became the industry standard for good quality light .
The problem is quietly being Discussed did flicker considerations Are not simple . Modern LED lights flicker thathave are likely to have a 120 - Hz fluctuation did Has A smooth alternating variation at twice the line frequency power . Even When this flicker Approaches 100 % , it results in a Significantly less- able notice flicker than that of magnetic ballasts . We recommend did the 120 - Hz ripple in the output of a driver shoulderstand be less than 10% for LED task and office lighting , LED decorative lighting while for (eg, cove lights , sconces , outdoor lighting , etc.) , as much as 100 % flicker 'may be acceptable.
Dimming methods and flicker
Dimming methodologies , HOWEVER , can impact flicker . In the output of an LED driver , the percentage of ripple at twice the line frequency is the parameter did corresponds to the flicker in the light output. Many led street light with solar panel produce dimming by switching the LED light on and off at a Relatively high frequency , a process called pulse- width modulation ( PWM) dimming or digital dimming . The human eye is completely Call oblivious to synthesis high frequencies and simply perceives less light .
Dimmable LED drivers exist , HOWEVER , did simply modulate the light on and off at twice the line frequency ; at low dim levels , the result can be a lot like the light output of old magnetic ballasts where the flicker 'may be Easily Perceived . In addition , if used with a triac dimmer , Which does not dim positive and negative half- cycles Equally , it june introduce a line frequency component to the PWM thatwill be perceptible to anyone.
Other LED drivers produce a uniform DC current level , Which is then adjusted downward to produce dimming . This methodology is sometimes referred by to as analog dimming . For task and office lighting , this approach is the most trouble - free kind of dimming to use, though it's likely to be more expensive than digital dimming .
More info you can visit:http://www.lead-lighting.com/products/sid109-1.htm
Constant voltage or current ?
The first question developers face is almost always the choice of constant -current or- voltage supply . There are two fundamental types of LED arrays - Those Which run off a constant voltage (CV) and Those Which run off a constant current (CC ) - and they're materially different inside . A constant voltage array wants containment devices to limit the current from going too high When the LEDs get hot , : such as resistors or constant current resistors ( CCRs ) or even a switching DC-DC regulator of somekind . By contrast , a constant current LED array will have LEDs connected in series and Perhaps several of synthesis strings connected in parallel.
You'll want to choose a constant voltage array under two Circumstances :
1) You have yet to deterministic mine your LED array and the application is one where you do not know exactly how many LED strings will be hung on supply did or what the current draw will be ( ie, cove lighting ) .
2) The LED array is of the constant voltage and variety THEREFORE Has A fixed range of current fixed output voltage for did . In this instance , you'll need to Ensure the driver did you select is the right voltage and did the allowable output current range is higher than the gross estimated current draw of your LED loads .
If you are aware of the current draw needed to match application light -level requirements , you'd probably choose a constant current array Because it 's the most efficient Usually arrangement . If your LED array requires a constant current , then you'll need a CC LED driver . This type of driver will only have a range of Certain Voltages Which It can drive ; there will be a minimum voltage and a maximum voltage Permissible . You need to Log Ensure did your LED array Has A voltage requirement did if inside this Permissible range .
The table reviews AC -to- DC driver Topologies and Their pros , cons , and applications . There is no wrong or right approach to driver selection . Instead , you need to match topology to the application requirements. Now let's address some specific issues .
The importance of dimming
Another early decision will consider the , importance of dimming and did human visual perception can INVOLVE and / or energy conservation issues . In order to select the right features , it helps to understand the characteristics of human perception . The human eye notices light changes on a scale Which Relates to what it 's already seeing and the light output of an LED lamp is Roughly proportional to the current going through it . As a result , dimming to 50 % is hardly noticeable to most people and 10% is Perceived as just a few degrees dimmer than that . THEREFORE , to have a discernable visual dimming effect , you need to be able to dim down to 1%. By comparison , movie theaters require dimming in the range of 0.1%.
The lack of sensitivity does not mean did dimming to above 1% is not useful . In fact , the situation is quite the contrary . If you dim LED to light down to 10% , you've just saved 90 % of its energy consumption , Which is very significant . Dimming by any degree is worthwhile for energy -saving purposes , but if you want to have a dimly -lit room or theater , you must have drivers Capable of dimming down below 1% , and down to 0.1 % for full-range dimming . The bottom line is did while the benefits of dimming in increments above the 1% range are not Often Perceived by the human eye , the energy benefits generated by dimming even a few degrees can have a tremendous impact on energy savings .
The flicker controversy
With dimming come flicker issues and the question of how much is too much flicker . In the lighting community , flicker is defined as the percentage fluctuation of the light (or LED current) at twice the line frequency , overexpressed as a fraction of the steady light (or DC current) through the LED .
Twenty years ago , magnetic ballasts fluorescent tubes drove , Which produced by intense flash near the peak of the power-line voltage cycle examined did the Entire light output consisted of a series of light flashes at twice the frequency of the power line . It was found did even though most people could not detect this fluctuation , some developed headaches and other stress symptoms When exposed to it. In response to the dissatisfaction with magnetic ballast flicker , electronic ballasts were developed thatwere Capable of less than 2 % flicker , Which Proved effective and Quickly Became the industry standard for good quality light .
The problem is quietly being Discussed did flicker considerations Are not simple . Modern LED lights flicker thathave are likely to have a 120 - Hz fluctuation did Has A smooth alternating variation at twice the line frequency power . Even When this flicker Approaches 100 % , it results in a Significantly less- able notice flicker than that of magnetic ballasts . We recommend did the 120 - Hz ripple in the output of a driver shoulderstand be less than 10% for LED task and office lighting , LED decorative lighting while for (eg, cove lights , sconces , outdoor lighting , etc.) , as much as 100 % flicker 'may be acceptable.
Dimming methods and flicker
Dimming methodologies , HOWEVER , can impact flicker . In the output of an LED driver , the percentage of ripple at twice the line frequency is the parameter did corresponds to the flicker in the light output. Many led street light with solar panel produce dimming by switching the LED light on and off at a Relatively high frequency , a process called pulse- width modulation ( PWM) dimming or digital dimming . The human eye is completely Call oblivious to synthesis high frequencies and simply perceives less light .
Dimmable LED drivers exist , HOWEVER , did simply modulate the light on and off at twice the line frequency ; at low dim levels , the result can be a lot like the light output of old magnetic ballasts where the flicker 'may be Easily Perceived . In addition , if used with a triac dimmer , Which does not dim positive and negative half- cycles Equally , it june introduce a line frequency component to the PWM thatwill be perceptible to anyone.
Other LED drivers produce a uniform DC current level , Which is then adjusted downward to produce dimming . This methodology is sometimes referred by to as analog dimming . For task and office lighting , this approach is the most trouble - free kind of dimming to use, though it's likely to be more expensive than digital dimming .
More info you can visit:http://www.lead-lighting.com/products/sid109-1.htm
2014年5月29日星期四
Digital Signage Need to Know: Product Consistency and Long Term Success with LED Sign Manufacturers.
The ISA International Sign Expo 2014 finished up this weekend, and by all accounts was a great success. I enjoyed talking face to face to partners, manufacturers and providers in the industry and meeting some great people. The experience brought up a couple of topics I would like to discuss today. Product Consistency and the Long Term Relationship with your manufacturer / supplier.
Although the Orlando show is slightly scaled down when compared to Las Vegas, it can still be a bit overwhelming for those new to the industry. One of the reasons for this is the 'wow' factor. Manufacturers want to put their best foot forward, and the good ones can back it up with a solid consistent product and experience long term. However, we should be careful of those who have a great looking product on the show floor, but supply a less than ideal product in reality.
Sometimes it's easy to spot;... Choppy graphics and slow animations look sub-par even on a large 20 ft led street light fixture But it can be difficult to tell in many cases, unless you've been in the industry for a while Super tight pixel pitches and flashy marketing material can sometimes make a supplier look better than they really are. It's worth the effort to dig deeper, and really make sure you are able to get the same product quality long term.
While a super tight 6-8mm pixel pitch may get your attention at the show, the vast majority of LED signs are going to be in the 16, 20, or 25mm range. How does the manufacturer measure up with these more affordable pitches? Are they going to use the same materials and quality in the product you order?
To be perfectly clear, there absolutely nothing wrong with a high resolution LED sign, they look spectacular and a good manufacturer will offer these pitches along with their standard line. Putting the highest resolution out there just happens to be a significant trend at these shows, .. and can sometimes skew a person's objectivity They key is providing you a consistent product regardless of the resolution, and supporting that product throughout it's lifetime Remember, your signs need to last longer than a 3 day indoor trade show; it's going to be outdoor , in the elements 24/7.
Unfortunately this is an issue for some manufacturers, often many located overseas. You may initially get a similar product to the one you saw at the show, maybe even the first 2-3 months or longer. However, at some point you may start to see changes to the product that you were unaware of, changes to the components and the quality of the material that affect the stability of your product in the field. When these changes occur, who do call?
You may get general answers or apologies, but do you really have any pull with the production team or product managers in a factory across the pacific ocean? Not very much, and unfortunately you may have to pay the price for their mistakes with your own reputation and money. Fixing these issues can be costly, and not often timely as you wait for parts to ship from limited supply of spare parts overseas.
Consistency is extremely important in our industry. You want a partner who has the ability to provide this too you on a regular basis. And when changes are made, to inform and document those changes for you. One of the important factors that impacts the ability to provide this is location. As I mentioned in an earlier post, domestic design and engineering are fundamental to producing quality LED signs. Additionally, domestic support is key to providing you the tools you need to maintain happy customers and functional signs.
Being able to contact a US based representative, who reports to leadership in the US, who oversees production and design team face to face, in the US, is a benefit not to be taken lightly. Feedback and communication from the sign providers onsite provides priceless information for manufacturers to better their product and services. It's difficult to get that level of communication from a factory thousands of miles away.
As I mentioned before, you, the sign provider bear the ultimate burden for your LED signs in the field and their long term operation. Your signs must stand up to the elements 24/7, and must be fixed in a timely manner when issues arise . The sign warranty plays a central role in this, and should be clear, underwritten, and backed up by real action, not just ink on paper. The industry standard is 5 years parts and "factory labor". This usually includes parts replacement, and the labor for the factory to repair parts at the factory. It should not be confused with a real onsite, or service labor warranty that includes actual onsite service to the sign. A few manufacturers offer the extra onsite labor warranty, and I highly recommend it.
Everyone wins when you choose a quality manufacturer. You get a partner invested in your success.LED street light fixture Manufacturer get a consistent product that will last, and when issues arise you both have a US based factory and support team ready to assist. Remember to keep your objectivity, don't get distracted by the 'wow' factor, and take the time to do your research and dig a bit deeper. Make sure you're doing business with a company who cares as much about your long term success as you do .
I hope this post has been informative and helpful. As usual, I welcome ALL constructive comments. Please feel free to comment and add anything I've missed, or additional tips you may have regarding this topic. Please visit www.vantageled.com for many other resources, white papers, and of course: Great looking LED Signs!
All posts / thoughts / writings are strictly the viewpoint of me and me alone and do not reflect nor speak for Vantage LED's beliefs, attitudes, thoughts, etc. Unless specifically stated.
More info you can visit:http://www.lead-lighting.com/products/sid108-1.htm
Although the Orlando show is slightly scaled down when compared to Las Vegas, it can still be a bit overwhelming for those new to the industry. One of the reasons for this is the 'wow' factor. Manufacturers want to put their best foot forward, and the good ones can back it up with a solid consistent product and experience long term. However, we should be careful of those who have a great looking product on the show floor, but supply a less than ideal product in reality.
Sometimes it's easy to spot;... Choppy graphics and slow animations look sub-par even on a large 20 ft led street light fixture But it can be difficult to tell in many cases, unless you've been in the industry for a while Super tight pixel pitches and flashy marketing material can sometimes make a supplier look better than they really are. It's worth the effort to dig deeper, and really make sure you are able to get the same product quality long term.
While a super tight 6-8mm pixel pitch may get your attention at the show, the vast majority of LED signs are going to be in the 16, 20, or 25mm range. How does the manufacturer measure up with these more affordable pitches? Are they going to use the same materials and quality in the product you order?
To be perfectly clear, there absolutely nothing wrong with a high resolution LED sign, they look spectacular and a good manufacturer will offer these pitches along with their standard line. Putting the highest resolution out there just happens to be a significant trend at these shows, .. and can sometimes skew a person's objectivity They key is providing you a consistent product regardless of the resolution, and supporting that product throughout it's lifetime Remember, your signs need to last longer than a 3 day indoor trade show; it's going to be outdoor , in the elements 24/7.
Unfortunately this is an issue for some manufacturers, often many located overseas. You may initially get a similar product to the one you saw at the show, maybe even the first 2-3 months or longer. However, at some point you may start to see changes to the product that you were unaware of, changes to the components and the quality of the material that affect the stability of your product in the field. When these changes occur, who do call?
You may get general answers or apologies, but do you really have any pull with the production team or product managers in a factory across the pacific ocean? Not very much, and unfortunately you may have to pay the price for their mistakes with your own reputation and money. Fixing these issues can be costly, and not often timely as you wait for parts to ship from limited supply of spare parts overseas.
Consistency is extremely important in our industry. You want a partner who has the ability to provide this too you on a regular basis. And when changes are made, to inform and document those changes for you. One of the important factors that impacts the ability to provide this is location. As I mentioned in an earlier post, domestic design and engineering are fundamental to producing quality LED signs. Additionally, domestic support is key to providing you the tools you need to maintain happy customers and functional signs.
Being able to contact a US based representative, who reports to leadership in the US, who oversees production and design team face to face, in the US, is a benefit not to be taken lightly. Feedback and communication from the sign providers onsite provides priceless information for manufacturers to better their product and services. It's difficult to get that level of communication from a factory thousands of miles away.
As I mentioned before, you, the sign provider bear the ultimate burden for your LED signs in the field and their long term operation. Your signs must stand up to the elements 24/7, and must be fixed in a timely manner when issues arise . The sign warranty plays a central role in this, and should be clear, underwritten, and backed up by real action, not just ink on paper. The industry standard is 5 years parts and "factory labor". This usually includes parts replacement, and the labor for the factory to repair parts at the factory. It should not be confused with a real onsite, or service labor warranty that includes actual onsite service to the sign. A few manufacturers offer the extra onsite labor warranty, and I highly recommend it.
Everyone wins when you choose a quality manufacturer. You get a partner invested in your success.LED street light fixture Manufacturer get a consistent product that will last, and when issues arise you both have a US based factory and support team ready to assist. Remember to keep your objectivity, don't get distracted by the 'wow' factor, and take the time to do your research and dig a bit deeper. Make sure you're doing business with a company who cares as much about your long term success as you do .
I hope this post has been informative and helpful. As usual, I welcome ALL constructive comments. Please feel free to comment and add anything I've missed, or additional tips you may have regarding this topic. Please visit www.vantageled.com for many other resources, white papers, and of course: Great looking LED Signs!
All posts / thoughts / writings are strictly the viewpoint of me and me alone and do not reflect nor speak for Vantage LED's beliefs, attitudes, thoughts, etc. Unless specifically stated.
More info you can visit:http://www.lead-lighting.com/products/sid108-1.htm
LED T8 Tube News, Plus Limited Time Sale
This is a big week in environmental news, as we await today's White House climate change report, and as we learn that led street light wholesale will outnumber the fluorescent tubes to be installed this year. A survey of professional lighting installers shows that SSL technology will make up 49% of their planned projects in 2014 - edging out fluorescent at 46% and almost doubling the projections from 2013.
This is the first year LED tube installations will outnumber fluorescent linear lighting, and it means buildings will now be more efficiently illuminated, and fewer mercury-tainted tubes will enter the waste stream as fluorescent T8s reach the end of useful service - typically after only a few thousand hours.
Waves of Savings.Genesys LED T8 sale frosted availableWe're celebrating the good news with a sale on our own 4-foot LED tubes made in the USA Today through Monday, May 12th 2014;. Save 20% on all Genesys 3.0 led street light supplier with coupon code WAVES.
To ensure years of superior quality lighting covered by our 5 year warranty, the Genesys 3.0 is built with Philips LUXEON LEDs and bundled with your choice of 20W or 38W driver - each powered under capacity to ensure upwards of 50,000 hours of service life.
In more LED T8 news, we're adding a clear lens option alongside the traditional frosted covered Genesys. The clear lens transmits 10% more light and is currently only available by special order, so call us at 1 (800) 986-0169 to claim yours today!
more info you can visit:http://www.lighting-ledlight.com/index.php/category/led-street-lighting/
This is the first year LED tube installations will outnumber fluorescent linear lighting, and it means buildings will now be more efficiently illuminated, and fewer mercury-tainted tubes will enter the waste stream as fluorescent T8s reach the end of useful service - typically after only a few thousand hours.
Waves of Savings.Genesys LED T8 sale frosted availableWe're celebrating the good news with a sale on our own 4-foot LED tubes made in the USA Today through Monday, May 12th 2014;. Save 20% on all Genesys 3.0 led street light supplier with coupon code WAVES.
To ensure years of superior quality lighting covered by our 5 year warranty, the Genesys 3.0 is built with Philips LUXEON LEDs and bundled with your choice of 20W or 38W driver - each powered under capacity to ensure upwards of 50,000 hours of service life.
In more LED T8 news, we're adding a clear lens option alongside the traditional frosted covered Genesys. The clear lens transmits 10% more light and is currently only available by special order, so call us at 1 (800) 986-0169 to claim yours today!
more info you can visit:http://www.lighting-ledlight.com/index.php/category/led-street-lighting/
New Low Price for the PR15 UltraThin LED Recessed Light
LED Waves is pleased to announce that the PR15 UltraThin LED Recessed Light has an affordable new price tag! At $ 49.95 (originally $ 69.95 per unit), this item is now an even more competitively priced alternative to halogen ceiling lights.
How did we manage cut $ 20.00 off the price per unit Before shipping the PR15 downlights out from LED Waves headquarters, we wire each one to your choice of dimmable or non-dimming LED driver -? Constituting a significant portion of the price of the finished product . But since these particular led street light with solar panel recessed lights have proven to be so popular, we are now able purchase these components in larger quantities and then transfer our bulk savings onto you, our customers!
Thus, while now drastically reduced in price, there is no change to the high quality components and performance that bring lighting designers, building contractors, and homeowners coming back to the PR15 UltraThin.
more info you can visit:http://www.lead-lighting.com/products/sid109-1.htm
How did we manage cut $ 20.00 off the price per unit Before shipping the PR15 downlights out from LED Waves headquarters, we wire each one to your choice of dimmable or non-dimming LED driver -? Constituting a significant portion of the price of the finished product . But since these particular led street light with solar panel recessed lights have proven to be so popular, we are now able purchase these components in larger quantities and then transfer our bulk savings onto you, our customers!
Thus, while now drastically reduced in price, there is no change to the high quality components and performance that bring lighting designers, building contractors, and homeowners coming back to the PR15 UltraThin.
more info you can visit:http://www.lead-lighting.com/products/sid109-1.htm
Updates to LED Waves’ Standard & 5-Year Warranty
. Recently, a major issue caught our attention of us here at LED Waves by way of the LEDs & Lighting group on LinkedIn In a discussion thread titled "LED Warranty small print -? What should you look out for" lighting professionals shared their experiences, good and bad, dealing with manufacturers' warranties.
We learned of suppliers and manufacturers who refused to honor (what we assumed were) very basic instances requiring warranty service:
if some, but not all, led high bay light price did not light up ("Hey, you're still getting SOME light out of it.")
if the luminaire's light output deteriorates up to 50% within their stated hours (Same as above Note:. the industry standard says that a lamp is spent after 30% deterioration of initial lumens.)
if a luminaire's bundled electronics - the LED driver, for instance -. stops working ("We didn't make that part, so it's not OUR problem.")
if the product wasn't registered at every point along the supply chain ("Yeah, we made this, but you didn't buy it directly from us; take it up with that guy.")
... And so on We were surprised to hear these horror stories, probably because (a) since so many of our clients are lighting designers and facility managers, they cannot accept this level of non-service in a warranty -. And we must abide by that; and (b) as both an LED lighting OEM and a direct supplier, we have to take responsibility for our products at every point from design, assembly, to burn-in testing before they reach your door We can't pass the. responsibility of basic warranty service off on anyone else.
5 year warranty
We promise, our fine print is not very fine at all.
In light of this, we decided to update our warranty. Read our amended standard warranty statement, as well as the extended 5 year warranty applicable to our LED lights made in the USA. Note that since we're an Original Equipment Manufacturer that also sells directly, any led high bay light for sale purchase is automatically covered by our warranty without having to register your purchase.
TL: DR:. The terms of our warranty are the same on our end In the extremely rare case of product failure, we will provide the same level of service our high end lighting professional customers have come to expect But with our new explicit wording. , we're hoping that all our customers (old and new) will understand the protection they're getting from the LED Waves warranty - the protection you deserve.
More info you can visit:http://www.lead-lighting.com/products/sid22-1.htm
We learned of suppliers and manufacturers who refused to honor (what we assumed were) very basic instances requiring warranty service:
if some, but not all, led high bay light price did not light up ("Hey, you're still getting SOME light out of it.")
if the luminaire's light output deteriorates up to 50% within their stated hours (Same as above Note:. the industry standard says that a lamp is spent after 30% deterioration of initial lumens.)
if a luminaire's bundled electronics - the LED driver, for instance -. stops working ("We didn't make that part, so it's not OUR problem.")
if the product wasn't registered at every point along the supply chain ("Yeah, we made this, but you didn't buy it directly from us; take it up with that guy.")
... And so on We were surprised to hear these horror stories, probably because (a) since so many of our clients are lighting designers and facility managers, they cannot accept this level of non-service in a warranty -. And we must abide by that; and (b) as both an LED lighting OEM and a direct supplier, we have to take responsibility for our products at every point from design, assembly, to burn-in testing before they reach your door We can't pass the. responsibility of basic warranty service off on anyone else.
5 year warranty
We promise, our fine print is not very fine at all.
In light of this, we decided to update our warranty. Read our amended standard warranty statement, as well as the extended 5 year warranty applicable to our LED lights made in the USA. Note that since we're an Original Equipment Manufacturer that also sells directly, any led high bay light for sale purchase is automatically covered by our warranty without having to register your purchase.
TL: DR:. The terms of our warranty are the same on our end In the extremely rare case of product failure, we will provide the same level of service our high end lighting professional customers have come to expect But with our new explicit wording. , we're hoping that all our customers (old and new) will understand the protection they're getting from the LED Waves warranty - the protection you deserve.
More info you can visit:http://www.lead-lighting.com/products/sid22-1.htm
New Rio Grande Waterproof LED Light Strip Increases Lumens Per Dollar
LED Waves is pleased to announce some exciting new upgrades to our brightest flexible light strip. The Rio Grande Waterproof is now available in longer 5 meter spools (approx. 16.4 feet) with bare wire ends. This is welcome news to our many lighting design customers who use the Rio Grande in bigger and brighter projects!
Previously available in only 3 meter spools, the 5 meter Rio Grande Waterproof Flexible buy led high bay lamps Strip features the same powerful LEDs, spacing, and overall technical specs. You can cut, connect, and control these strips the same way you would with the original.
There are a couple of slight changes, however, that only add to the quality of this popular led high bay light supplier First, we improved the waterproof sleeve on the Rio Grande, using a new silicon blend for better light transmission from all sides -. While maintaining its IP65 protection.
We also improved the Rio Grande price! By ordering longer lengths and larger quantities of these strips in 2700K and 4000K (the most commonly used CCTs for our LED strip lights), we got great rates on our stock, which we're passing onto our customers.
The Rio Grande is now more affordable than ever at $ 119.95 per 5 meter spool. With up to 1,014 lumens per meter, it's the best & brightest value in LED light strips. Call us at 1 (800) 986-0169 for custom cutting and sealing or other special orders.
more info you can visit:http://www.lead-lighting.com/products/sid20-1.htm
Previously available in only 3 meter spools, the 5 meter Rio Grande Waterproof Flexible buy led high bay lamps Strip features the same powerful LEDs, spacing, and overall technical specs. You can cut, connect, and control these strips the same way you would with the original.
There are a couple of slight changes, however, that only add to the quality of this popular led high bay light supplier First, we improved the waterproof sleeve on the Rio Grande, using a new silicon blend for better light transmission from all sides -. While maintaining its IP65 protection.
We also improved the Rio Grande price! By ordering longer lengths and larger quantities of these strips in 2700K and 4000K (the most commonly used CCTs for our LED strip lights), we got great rates on our stock, which we're passing onto our customers.
The Rio Grande is now more affordable than ever at $ 119.95 per 5 meter spool. With up to 1,014 lumens per meter, it's the best & brightest value in LED light strips. Call us at 1 (800) 986-0169 for custom cutting and sealing or other special orders.
more info you can visit:http://www.lead-lighting.com/products/sid20-1.htm
2014年5月28日星期三
LSI Industries Inc. to Provide LED Lighting to Shell Oil National Program
LSI Industries Inc. Reported today that it has been selected by Shell Oil Company to participate in Shell's National Wholesaler Co-op Program to make available LED technology lighting products to their network of wholesalers and dealers that brand Shell across locations in North America.
With this program, Shell announced to its network recently that they have teamed up with LSI Petroleum Lighting to "bring an enhanced Shell led street light fixture program that now includes one of the most recognizable brand names and requested lighting products in the petroleum industry."
Commenting on this relationship with Shell, Scott D. Ready, President of LSI Industries, said, "We are excited to be included in this new and expanded program for Shell and expect to begin servicing their network immediately. It is rewarding to be recognized for the innovative technology and the unparalleled service resource that LSI represents to the Shell team. Building on our industry-leading Legacy canopy fixture released to the market last year, we continue to expand our LED product solutions to provide a faster payback for the Petroleum retail and convenience store operators as they convert to LED lighting. "
"Safe Harbor" Statement under the Private Securities Litigation Reform Act of 1995
This document contains certain forward-looking statements that are subject to numerous assumptions, risks or uncertainties. The Private Securities Litigation Reform Act of 1995 provides a safe harbor for forward-looking statements. Forward-looking statements may be identified by words such as "estimates , "" anticipates, "" projects, "" plans, "" expects, "" intends, "" believes, "" seeks, "" may, "" will, "" should "or the negative versions of those words and similar expressions, and by the context in which they are used. Such statements, whether expressed or implied, are based upon current expectations of the Company and speak only as of the date made. Actual results could differ materially from those contained in or implied by such forward-looking statements as a result of a variety of risks and uncertainties over which the Company may have no control. These risks and uncertainties include, but are not limited to, the impact of competitive products and services, product demand and market acceptance risks, potential costs associated with litigation and regulatory compliance, reliance on key customers, financial difficulties experienced by customers, led street light fixture Manufacturer and seasonal nature of our business, the adequacy of reserves and allowances for doubtful accounts, fluctuations in operating results or costs whether as a result of uncertainties inherent in tax and accounting matters or otherwise, unexpected difficulties in integrating acquired businesses, the ability to retain key employees of acquired businesses, unfavorable economic and market conditions, and the results of asset impairment assessments. You are cautioned to not place undue reliance on these forward-looking statements. In addition to the factors described in this paragraph, the risk factors identified in our Form 10-K and other filings the Company may make with the SEC constitute risks and uncertainties that may affect the financial performance of the Company and are incorporated herein by reference. The Company does not undertake and hereby disclaims any duty to update any forward-looking statements to reflect subsequent events or circumstances.
more info you can visit:http://www.lighting-ledlight.com/index.php/category/led-street-lighting/
With this program, Shell announced to its network recently that they have teamed up with LSI Petroleum Lighting to "bring an enhanced Shell led street light fixture program that now includes one of the most recognizable brand names and requested lighting products in the petroleum industry."
Commenting on this relationship with Shell, Scott D. Ready, President of LSI Industries, said, "We are excited to be included in this new and expanded program for Shell and expect to begin servicing their network immediately. It is rewarding to be recognized for the innovative technology and the unparalleled service resource that LSI represents to the Shell team. Building on our industry-leading Legacy canopy fixture released to the market last year, we continue to expand our LED product solutions to provide a faster payback for the Petroleum retail and convenience store operators as they convert to LED lighting. "
"Safe Harbor" Statement under the Private Securities Litigation Reform Act of 1995
This document contains certain forward-looking statements that are subject to numerous assumptions, risks or uncertainties. The Private Securities Litigation Reform Act of 1995 provides a safe harbor for forward-looking statements. Forward-looking statements may be identified by words such as "estimates , "" anticipates, "" projects, "" plans, "" expects, "" intends, "" believes, "" seeks, "" may, "" will, "" should "or the negative versions of those words and similar expressions, and by the context in which they are used. Such statements, whether expressed or implied, are based upon current expectations of the Company and speak only as of the date made. Actual results could differ materially from those contained in or implied by such forward-looking statements as a result of a variety of risks and uncertainties over which the Company may have no control. These risks and uncertainties include, but are not limited to, the impact of competitive products and services, product demand and market acceptance risks, potential costs associated with litigation and regulatory compliance, reliance on key customers, financial difficulties experienced by customers, led street light fixture Manufacturer and seasonal nature of our business, the adequacy of reserves and allowances for doubtful accounts, fluctuations in operating results or costs whether as a result of uncertainties inherent in tax and accounting matters or otherwise, unexpected difficulties in integrating acquired businesses, the ability to retain key employees of acquired businesses, unfavorable economic and market conditions, and the results of asset impairment assessments. You are cautioned to not place undue reliance on these forward-looking statements. In addition to the factors described in this paragraph, the risk factors identified in our Form 10-K and other filings the Company may make with the SEC constitute risks and uncertainties that may affect the financial performance of the Company and are incorporated herein by reference. The Company does not undertake and hereby disclaims any duty to update any forward-looking statements to reflect subsequent events or circumstances.
more info you can visit:http://www.lighting-ledlight.com/index.php/category/led-street-lighting/
LG Electronics Expands U.S. Lighting Business Marketplace With Innovative LED Technologies
Electronics USA is shedding new light on high-performance energy efficient LED (Light-Emitting Diode) lighting solutions for commercial applications.
New LG LED lighting troffers - the most energy efficient available * in the United States today - provide designers, property owners and contractors with the latest in lighting technology and significant energy savings, assuring a long-term return on investment A troffer is a recessed. rectangular light fixture that fits into a ceiling grid.
LG's LED troffers provide outstanding illumination for a variety of environments while maintaining a sleek, modern appearance, according to Sean Lafferty, head of LG Electronics USA's led indoor lighting wholesale business. They also represent a great value, because LG's technology delivers up to 40 percent more energy savings than competing LED troffers. They are available in 2'x2 'and 2'x4' configurations as either lay-in or retrofit fixtures to provide flexible installation options.
"We're hearing excellent feedback about energy and maintenance cost savings from customers who have already installed our troffers in their office buildings and retail locations," said Lafferty. "LG is committed to providing solutions that not only help maximize energy savings for our customers , but also deliver high-quality and attractive solutions, and look forward to expanding our reach with these products. "
LG's LED troffers are a great option for those seeking lighting solutions for retrofits, as they maximize energy savings and provide a high return on investment, Lafferty explained. "They can typically be installed by qualified contractors in less than 10 minutes. Upgrading to LG's LED product is easy and affordable thanks, in part, to a host of public and private rebate programs now in place, "he said. This includes state, federal and local tax credits as well as special financing incentives. Customers have experienced paybacks in less than two years. **
LG troffers provide dimming control by ZigBee ® wireless communication, enabling easy integration with third party controls systems for even further energy savings with daylight harvesting, occupancy sensing and automatic timers. The ZigBee feature allows for impressive installation cost savings, and by eliminating the need for additional communications modules, is less expensive to maintain over time. With ZigBee wireless, LG led outdoor lighting wholesale provide commercial installations with industry-leading efficacy, greater installation flexibility and lower labor cost, ideal for hard-to-wire applications.
Key features of the LG LED troffers include:
• Low-glare optic system under 18 UGR (unified glare rating)
• 70 percent luminance over 200,000 hours
• 0-10 Volt dimming
• 2400 -, 3300 -, 4400 -, and 5800-lumen packages available for upgrade from 2 -, 3 -, or 4-lamp T8 fluorescent fixtures
• Power factor of less than 95 percent and dimming capability
LG is collaborating with Daintree Networks, the leading provider of open, networked wireless solutions for smart building control and energy management, to create a fully integrated LED lighting solution with wireless control for commercial settings. Embedding wireless communication capability directly into LG's LED drivers enables seamless interaction with Daintree's ControlScope ™ networked wireless control solution.
More info you can visit:http://www.lighting-ledlight.com/index.php/tag/led-outdoor-lighting-wholesale/
New LG LED lighting troffers - the most energy efficient available * in the United States today - provide designers, property owners and contractors with the latest in lighting technology and significant energy savings, assuring a long-term return on investment A troffer is a recessed. rectangular light fixture that fits into a ceiling grid.
LG's LED troffers provide outstanding illumination for a variety of environments while maintaining a sleek, modern appearance, according to Sean Lafferty, head of LG Electronics USA's led indoor lighting wholesale business. They also represent a great value, because LG's technology delivers up to 40 percent more energy savings than competing LED troffers. They are available in 2'x2 'and 2'x4' configurations as either lay-in or retrofit fixtures to provide flexible installation options.
"We're hearing excellent feedback about energy and maintenance cost savings from customers who have already installed our troffers in their office buildings and retail locations," said Lafferty. "LG is committed to providing solutions that not only help maximize energy savings for our customers , but also deliver high-quality and attractive solutions, and look forward to expanding our reach with these products. "
LG's LED troffers are a great option for those seeking lighting solutions for retrofits, as they maximize energy savings and provide a high return on investment, Lafferty explained. "They can typically be installed by qualified contractors in less than 10 minutes. Upgrading to LG's LED product is easy and affordable thanks, in part, to a host of public and private rebate programs now in place, "he said. This includes state, federal and local tax credits as well as special financing incentives. Customers have experienced paybacks in less than two years. **
LG troffers provide dimming control by ZigBee ® wireless communication, enabling easy integration with third party controls systems for even further energy savings with daylight harvesting, occupancy sensing and automatic timers. The ZigBee feature allows for impressive installation cost savings, and by eliminating the need for additional communications modules, is less expensive to maintain over time. With ZigBee wireless, LG led outdoor lighting wholesale provide commercial installations with industry-leading efficacy, greater installation flexibility and lower labor cost, ideal for hard-to-wire applications.
Key features of the LG LED troffers include:
• Low-glare optic system under 18 UGR (unified glare rating)
• 70 percent luminance over 200,000 hours
• 0-10 Volt dimming
• 2400 -, 3300 -, 4400 -, and 5800-lumen packages available for upgrade from 2 -, 3 -, or 4-lamp T8 fluorescent fixtures
• Power factor of less than 95 percent and dimming capability
LG is collaborating with Daintree Networks, the leading provider of open, networked wireless solutions for smart building control and energy management, to create a fully integrated LED lighting solution with wireless control for commercial settings. Embedding wireless communication capability directly into LG's LED drivers enables seamless interaction with Daintree's ControlScope ™ networked wireless control solution.
More info you can visit:http://www.lighting-ledlight.com/index.php/tag/led-outdoor-lighting-wholesale/
Plessey Semiconductor Expands GaN-on-Silicon LED Production using AIXTRON Technology
Plessey Semiconductors Ltd today announced that it has purchased another CRIUS II-XL MOCVD system for use in the manufacture of Gallium Nitride LEDs on Silicon wafers (GaN-on-Si). The company is further expanding its production capacities in this area. The Close Coupled Showerhead system recently delivered with a 7x6-inch configuration will supplement an existing production system from AIXTRON.
Dr. Keith Strickland, Chief Technology Officer for Plessey said, "Our MaGICTM (Manufactured on GaN-on-Si I / C) led outdoor lighting wholesale in particular has been successfully launched this past year. As a result, we now plan to step up our production. To this end, and given our positive experience with AIXTRON's CRIUS II-XL system, we have purchased a further system of this type and are thus maintaining our successful cooperation with AIXTRON. "
"CRIUS II-XL convinced us with its high throughput rates and low operating costs for GaN layer growth on 6-inch silicon substrates. Moreover, AIXTRON is actively supporting us in further optimizing our production processes", added Mike Snaith, Operations Director for Plessey .
"We are delighted by the renewed order from Plessey", commented Dr. Frank Schulte, Vice President AIXTRON Europe. "It offers further confirmation that Gallium Nitride-on-Silicon, a high-performance, efficient epitaxy process, is becoming increasingly established as an alternative to growth on sapphire. The associated potential production cost savings will further promote the establishment of LED as a light source. AIXTRON is well prepared for this market development and will also be supporting Plessey in further optimizing its GaN-on-Silicon technology. "
Plessey Semiconductors Ltd. Is a LED commercial lighting wholesale in the development and manufacture of semiconductor products used in lighting, sensing, measurement and control applications. Plessey's products are found in a wide range of markets, including communications, medical technology, aerospace and space travel, as well as in the defense and automotive industry.
More info you can visit:http://www.lighting-ledlight.com/index.php/tag/led-commercial-lighting-wholesale/
Dr. Keith Strickland, Chief Technology Officer for Plessey said, "Our MaGICTM (Manufactured on GaN-on-Si I / C) led outdoor lighting wholesale in particular has been successfully launched this past year. As a result, we now plan to step up our production. To this end, and given our positive experience with AIXTRON's CRIUS II-XL system, we have purchased a further system of this type and are thus maintaining our successful cooperation with AIXTRON. "
"CRIUS II-XL convinced us with its high throughput rates and low operating costs for GaN layer growth on 6-inch silicon substrates. Moreover, AIXTRON is actively supporting us in further optimizing our production processes", added Mike Snaith, Operations Director for Plessey .
"We are delighted by the renewed order from Plessey", commented Dr. Frank Schulte, Vice President AIXTRON Europe. "It offers further confirmation that Gallium Nitride-on-Silicon, a high-performance, efficient epitaxy process, is becoming increasingly established as an alternative to growth on sapphire. The associated potential production cost savings will further promote the establishment of LED as a light source. AIXTRON is well prepared for this market development and will also be supporting Plessey in further optimizing its GaN-on-Silicon technology. "
Plessey Semiconductors Ltd. Is a LED commercial lighting wholesale in the development and manufacture of semiconductor products used in lighting, sensing, measurement and control applications. Plessey's products are found in a wide range of markets, including communications, medical technology, aerospace and space travel, as well as in the defense and automotive industry.
More info you can visit:http://www.lighting-ledlight.com/index.php/tag/led-commercial-lighting-wholesale/
Leading the LED Lighting Fully Automation Road
LED lighting is labor-intensive industries, But in recent years has been plaguedby recruitment difficulties faced by personnel instability and other factors, Therefore, the use of automated production lines to replace the manual, while addressing the current laborshortage, saving labor costs and the growing market demand doubled.
However, LED lighting products do not exist design standards yet, so it created a dazzling variety LED lighting for market.Thus, to meet today's diverse LED Panel light 18w products.
Even the face of the future a variety of new process technology can be quickly and effectively correspond, Maximize the utilization rate of the production of automated assembly line is bound to be the future trend.
"Automation ability is the key factor for manufacturing industry successful," said DY-Precision Industrial Co., Ltd. General Manager Chitser Ho.
According to our extensive experience and knowledge for the production process of LED lighting related and Electronic manufacturing plant automation.
If the manufacturer wants to achieve a higher level of automation, choose we, you definitely made the right choice! We understand automated production technology and production and development trend of LED lighting-with our highly innovative product integration capability and RD Team long term extensive experience for fully automated engineering.For corporate facing a variety of automation challenges, we are the right partner. "
For World LED lighting manufacturer manufacturing the First-class automated production lines
DY new generation of LFB-1200 and LFT-600 automated production lines,
Fully able to meet the LED lighting industry demand for flexibility, high-performance, high-UPH. Under the conditions of the stability of the incoming, LED Panel light 36w and tube production capacity were UPH1200 ~ 1500 and UPH600 ~ 800, LFB-1200 and LFT -600 automated production line revolutionary design, will be a large number of LED lamp and LED bulb production first choice!
More info you can visit:http://www.lead-lighting.com/led-panel/rf-wireless-color-temperature-dimmable.htm
Lumenpulse harnesses AC-LED driver in linear cove luminaire
Lumenpulse has announced the Lumencove Nano LED luminaire that targets linear cove lighting applications with a scalable 1-ft or 4-ft design that can be cascaded into longer runs The fixture also integrates AC-LED driver technology -. A technology the company calls Lumendrive - directly onto the printed circuit board (PCB) that hosts the LEDs so that the fixture can be connected directly to the AC line.
Lumenpulse harnesses AC-LED driver in linear cove luminaire
The company is touting the Lumendrive technology as eliminating the power supply or driver that's commonly used with outdoor LED Street Light 200w , and therefore boosting the fixture reliability. But as we've discussed before, AC-driver technology is really just another driver topology that comes with advantages and disadvantages relative to the more common AC-DC driver used in solid-state lighting (SSL).
"By removing the power supply, we reduced the size of the product and improved performance - without sacrificing sustainability or reliability," said Greg Campbell, senior vice president and CTO at Lumenpulse "Lumendrive lets us avoid the typical efficiency losses that occur in. the AC-to-DC power conversion with embedded power supplies, allowing us to provide best-in-class efficiency. "
The fixture delivers 100 lm / W in efficacy and 559 lm / ft. Those specifications are not industry tops but are certainly competitive. In the past, AC-LED-based products have trailed more traditional DC-driven designs in efficacy and lumen output but the gap has closed considerably.
Still, the comparison of the Lumenpulse design with other products must go deeper. The company is using a custom IC to implement the Lumendrive AC-drive technology. Campbell would not name the IC supplier but said that Lumenpulse had found a partner that was using technology similar to a typical AC-LED step-drive topology in a completely different application and was able to have that unnamed company customize the Lumendrive implementation without facing the huge nonrecurring engineering costs associated with a full-custom IC.
The step-drive approach, used by a number of companies including Seoul Semiconductor, groups LEDs into segments with the segments forming a series string. As the AC voltage level rises, first one and then the subsequent segments sequentially light up. The downside to such a topology is that all of the LEDs are not switched on for the same amount of time. The different duty cycles can result in uneven light levels from segment to segment, and lower overall efficacy.
The step-drive technique essentially reduces the utilization level of the LEDs in a system, and that would effectively add cost because more LEDs would be required to reach the same light levels of a DC-driven alternative. Campbell points out, however, that the simpler driver more than makes up for the LED cost differential.
At the system level, however, the product designers also had to compensate for the different light levels associated with LEDs in different segments. AC-LED technology has been used in applications such as downlights where the LEDs are grouped closely together and the differences in light levels between individual components are not as important as the total lumen output in the beam. In the linear applications, with individual LEDs spaced apart along the length, inconsistencies could be noticeable.
Color and lumen consistency
Campbell said the company employed two techniques to deliver consistency along the length of the Lumencove fixture The company used binned LED Street Light 200w price and placed the brighter LEDs in segments that have lower duty cycles -. The LEDs at the top end of the series string relative to the rising AC line voltage. Moreover, the design intersperses LEDs from different segments along the length of the fixtures as opposed to just connecting each segment sequentially along the fixture. Specifiers will have to peruse the photometric tests, available to potential customers from Lumenpulse, and their own evaluations to determine if the consistency matches specific application requirements.
Back to the product, Lumencove Nano is easily scaled for runs as long as 300 ft. Indeed, the sections include electrical connectors that can pass through the AC power from segment to segment. Each segment includes its own AC-driver implementation.
The design is dimmable using 0-10V controls. Indeed, Campbell said dimming performance was one of the primary motivations that drove the company to develop the Lumendrive IC. He said that most other AC-drive implementations lack uniform dimming capability at the low end of the dimming range. Campbell would not reveal details of how the company implemented the dimming capability beyond saying that the design modulates the current to each segment.
The Lumencove Nano can also take dimming controls over the company's Lumentalk power-line network scheme. And the company can bridge phase-controlled dimmers to Lumentalk.
Lumenpulse will warranty the new product for ten years and is projecting 100,000 hours of life. Presumably, the AC-driver technology is behind such longevity, although there have been DC-driven SSL products on the market with such warranties for going on two years. Clearly, you can realize reliable products using a number of driver topologies, but lighting designers and specifiers will choose products taking into account many factors including color and lumen consistency, and efficacy - as well as lifetime.
More info you can visit:http://www.lead-lighting.com/led-street-light/led-street-light-200w.htm
Lumenpulse harnesses AC-LED driver in linear cove luminaire
The company is touting the Lumendrive technology as eliminating the power supply or driver that's commonly used with outdoor LED Street Light 200w , and therefore boosting the fixture reliability. But as we've discussed before, AC-driver technology is really just another driver topology that comes with advantages and disadvantages relative to the more common AC-DC driver used in solid-state lighting (SSL).
"By removing the power supply, we reduced the size of the product and improved performance - without sacrificing sustainability or reliability," said Greg Campbell, senior vice president and CTO at Lumenpulse "Lumendrive lets us avoid the typical efficiency losses that occur in. the AC-to-DC power conversion with embedded power supplies, allowing us to provide best-in-class efficiency. "
The fixture delivers 100 lm / W in efficacy and 559 lm / ft. Those specifications are not industry tops but are certainly competitive. In the past, AC-LED-based products have trailed more traditional DC-driven designs in efficacy and lumen output but the gap has closed considerably.
Still, the comparison of the Lumenpulse design with other products must go deeper. The company is using a custom IC to implement the Lumendrive AC-drive technology. Campbell would not name the IC supplier but said that Lumenpulse had found a partner that was using technology similar to a typical AC-LED step-drive topology in a completely different application and was able to have that unnamed company customize the Lumendrive implementation without facing the huge nonrecurring engineering costs associated with a full-custom IC.
The step-drive approach, used by a number of companies including Seoul Semiconductor, groups LEDs into segments with the segments forming a series string. As the AC voltage level rises, first one and then the subsequent segments sequentially light up. The downside to such a topology is that all of the LEDs are not switched on for the same amount of time. The different duty cycles can result in uneven light levels from segment to segment, and lower overall efficacy.
The step-drive technique essentially reduces the utilization level of the LEDs in a system, and that would effectively add cost because more LEDs would be required to reach the same light levels of a DC-driven alternative. Campbell points out, however, that the simpler driver more than makes up for the LED cost differential.
At the system level, however, the product designers also had to compensate for the different light levels associated with LEDs in different segments. AC-LED technology has been used in applications such as downlights where the LEDs are grouped closely together and the differences in light levels between individual components are not as important as the total lumen output in the beam. In the linear applications, with individual LEDs spaced apart along the length, inconsistencies could be noticeable.
Color and lumen consistency
Campbell said the company employed two techniques to deliver consistency along the length of the Lumencove fixture The company used binned LED Street Light 200w price and placed the brighter LEDs in segments that have lower duty cycles -. The LEDs at the top end of the series string relative to the rising AC line voltage. Moreover, the design intersperses LEDs from different segments along the length of the fixtures as opposed to just connecting each segment sequentially along the fixture. Specifiers will have to peruse the photometric tests, available to potential customers from Lumenpulse, and their own evaluations to determine if the consistency matches specific application requirements.
Back to the product, Lumencove Nano is easily scaled for runs as long as 300 ft. Indeed, the sections include electrical connectors that can pass through the AC power from segment to segment. Each segment includes its own AC-driver implementation.
The design is dimmable using 0-10V controls. Indeed, Campbell said dimming performance was one of the primary motivations that drove the company to develop the Lumendrive IC. He said that most other AC-drive implementations lack uniform dimming capability at the low end of the dimming range. Campbell would not reveal details of how the company implemented the dimming capability beyond saying that the design modulates the current to each segment.
The Lumencove Nano can also take dimming controls over the company's Lumentalk power-line network scheme. And the company can bridge phase-controlled dimmers to Lumentalk.
Lumenpulse will warranty the new product for ten years and is projecting 100,000 hours of life. Presumably, the AC-driver technology is behind such longevity, although there have been DC-driven SSL products on the market with such warranties for going on two years. Clearly, you can realize reliable products using a number of driver topologies, but lighting designers and specifiers will choose products taking into account many factors including color and lumen consistency, and efficacy - as well as lifetime.
More info you can visit:http://www.lead-lighting.com/led-street-light/led-street-light-200w.htm
2014年5月23日星期五
Proper driver design eliminates LED light strobe flicker
LED-driver architecturen bepalen SSL flikkeren , verklaren Zhaoqi MAO , LANE GE , en GARY HUA , maar technieken die rimpel onderdrukken kan kosten blijken effectief en leveren comfortabele - LED gebaseerde verlichtingsoplossingen .
Vervanging van traditionele gloeilampen en tl- lampen met een efficiëntere en duurzamere LED - gebaseerde solid- state lighting ( SSL ) is een onmiskenbare trend in de verlichtingsindustrie . Aangezien SSL armaturen rechtstreeks zijn aangesloten op de AC- lijn , zoals met legacy verlichting , bestaat het risico dat 100 Hz of 120 Hz flikkering kunnen optreden als gevolg van het rijden rimpelspanning aan de uitgang van de voeding is . Flicker kunnen mensen ongemakkelijk , waardoor hoofdpijn en andere kwalen maken terwijl het menselijk oog de flikkering niet kan detecteren. zorgvuldige LED-driver ontwerp kan flikkeren minimaliseren en ervoor te zorgen dat SSL levert op zijn energie - efficiëntie belofte door middel van brede implementatie.
Inderdaad, led street lights price en armatuur fabrikanten willen graag de flikkering probleem op te lossen , en ze zijn grotendeels wendde zich tot de fabrikanten bestuurder voor een oplossing, omdat uiteindelijk de bestuurder bepaalt de mate van flikkering . Dit artikel zal de oorzaak en karakterisering van flikkering uitleggen , beschrijven hoe het voorkomt in LED-verlichting , en uitleggen hoe ingenieurs kan inruilen verschillende driver topologieën in een poging om de juiste kosten / baten combinatie te vinden . We zullen een rimpelspanningonderdrukker circuit dat is een kosteneffectieve en flexibele manier van uitvoering trillingsvrije LED beschrijven verlichting .
marktverwachtingen
Het is een goed erkend trend die LED-verlichting zal legacy bronnen vervangen , waaronder gloeilampen en tl-lampen en buizen in de komende jaren . Omdat LED is een nieuwe generatie lichtbron met elektronische roots , de markt verwacht dat niet alleen de hogere SSL -systeem - level werkzaamheid , maar ook een betere verlichting milieu .
Net als de erfenis verlichting technologieën , maar de meeste LED-lampen zijn direct aangesloten op het lichtnet , dat werkt op 50 of 60 Hz in verschillende wereldregio's . Zelfs na correctie voor frequenties van 100 of 120 Hz , kan ieder - lijn verbonden flikkering detecteerbaar zijn het menselijk oog door de relatief lage frequenties betrokken . Inderdaad, de gerectificeerde regel kan leiden tot strobe flikkeren , die de eerder genoemde nood bij mensen kunnen veroorzaken .
In het bijzonder , LED-driver ontwerpen die afhankelijk zijn van een eentraps architectuur om zowel Power Factor Correction ( PFC ) en uitgaande stroom verwerken zijn bijzonder gevoelig voor flikkeren . Onder andere oorzaken , wordt flikkering beïnvloed door de LED- rimpelspanning . Maar er zijn tal van methoden om het probleem , waaronder een rimpelspanningonderdrukker circuit te elimineren . SSL product ontwikkelaars nodig hebben om de aanpak te evalueren en te kiezen voor een driver die de applicatie-eisen in kosten en prestaties voldoen . verschillende niveaus van flikkering aanvaardbaar zijn in verschillende toepassingen . een ontwerp van het systeem , dat is onaanvaardbaar in indoor toepassingen vanwege flikkeren kan presteren prima in een openlucht straat of terreinverlichting rol .
Het effect van flikkeringen
Laten we nu onderzoeken flikkeren Volgens de nota " Een overzicht van de literatuur over licht flikkeren : Ergonomie , biologische eigenschappen , de potentiële gevolgen voor de gezondheid , en methoden ." Dat in 2010 werd gepubliceerd door het Institute of Electrical and Electronic Engineers ( IEEE ) , licht flikkeren frequentie in de 3-70 Hz - assortiment is zeer waarneembaar door mensen en dit kan ze erg ongemakkelijk ( http://bit.ly/1iL2vjq en http://bit.ly/NAtjXq ) . Zelfs repetitieve zwaailichten en statische herhalende geometrische patronen kunnen aanvallen bij deze individuen induceren , en het optreden bedraagt ongeveer 0,025% . kan dit type trilling gemakkelijk opgelost worden door de bestuurder , en normaal beschouwen we de bestuurder instabiel als dat soort frequentie kan worden gezien in de output stroomrimpel golfvorm.
Nu echter, mensen beginnen om meer aandacht te besteden aan de blootstelling op lange termijn onder hogere frequentie flikkering in de 70-160 Hz heeft . Dergelijke flikkeren kan malaise , hoofdpijn en slechtziendheid veroorzaken . Sommige onderzoekers beweren zelfs het netvlies kan voelen flikkeren tot 200 Hz , maar tests hebben aangetoond dat boven 160 Hz de gezondheidseffecten van flikkering zijn verwaarloosbaar. Vanwege de eerder genoemde verholpen lijn frequenties van 100 en 120 Hz , zullen we ons richten op het verminderen van flikkering in dat bereik hier . en in werkelijkheid de menselijke gezondheidseffecten van 100 - of 120 - Hz flikkering is een functie van niet alleen de frequentie maar ook de fysieke en fysiologische factoren .
Het definiëren van flikkering
Moeten we eerst begrijpen hoe flikkeren wordt gekenmerkt . De Illuminating Engineering Society of North America ( IESNA ) vrijgegeven van de definitie van " procent flikkeren " en " flicker index " in de negende editie van De IESNA Lighting Handbook. Figuur 1 . Toont hoe de metrics gedefinieerd .
Figuur 1 . . IES definieert flikkeren index .
Figuur 1 . . IES definieert flikkeren index .
Percentage flikkering is een relatieve maat voor de cyclische variatie van de output van een lichtbron ( dwz procent modulatie ) . Dit wordt ook wel aangeduid als de " modulatie . " Verwijzend naar figuur 1 . Je procent flikkering berekenen van de maximale ( a ) en minimum ( B ) lichtopbrengst niveaus . verdeel de som van a en B door het verschil van de twee tot een percentage verkrijgen .
Flicker index is gedefinieerd in de IESNA handboek als een " betrouwbare relatieve maat van de cyclische variatie in de productie van verschillende bronnen op een gegeven macht frequentie. Het houdt rekening met de golfvorm van de lichtopbrengst als de amplitude . " The flicker index veronderstelt waarden van 0 tot 1.0, met 0 voor een constante lichtopbrengst . hogere waarden duiden op een verhoogde kans opvallende licht flikkeren , en stroboscopisch effect . opnieuw verwijzend naar figuur 1 . , de index berekend door deling Area 1 door de som van Area 1 en zone 2 .
Tabel 1 . Samenvatting van procent flikkeren en flikkering index voor lichtbronnen .
Zoals eerder vermeld , naast de frequentie , de trilling index heeft een significant effect op hoe licht maakt mensen voelen . Hogere trilling index betekent meer gevoeligheid voor het menselijk oog en een slechtere comfort . Tabel 1 toont de typische flikkering index van ander licht motoren volgens de krant " de evaluatie van flikkering in LED-armaturen " geschreven door Michael Grather , voorzitter van Armatuur Testen Laboratory , en geplaatst op de Raad voor optische straling metingen ( CORM ) website.
SSL lichtbron uitgang
Na gedefinieerd flikkeren, laten we eens kijken hoe een LED lichtbron actief is. LED lichtopbrengst is vrijwel lineair met de stroom van de regelaar . Kennisnemen van elke high - power LED data sheet en je kunt de lineariteit zien in grafieken die plot vooruit huidige opzichte van lichtstroom . Dergelijke een perceel maakt het heel duidelijk dat de stroom van de regelaar is een kritische bron van LED-licht flikkeren , en constante stroomtoevoer is de primaire taak van de LED-driver .
Wanneer we praten 100-120 Hz flikkering , meestal zijn we gericht op binnenverlichting toepassingen . Er zijn nogal wat led street lighting Manufacturer regelingen voor binnenverlichting die een constante stroom kan leveren . Bijvoorbeeld eenvoudige stroombegrenzende weerstanden , lineaire halfgeleider regelgeving , en schakelen pulse - width modulation ( PWM ) regulering volgende AC rectificatie zijn allemaal mogelijkheden . Maar die regelingen zijn buiten het bereik van deze omdat ze niet in staat om de macht (PF ) nodig voor indoor commerciële toepassingen. Typisch , commerciële toepassingen vereisen een PF groter dan 0,9 . Steeds meer landen en normen verenigingen zoals Energy Star en DesignLights Consortium ( DLC ) vereisen verlichting tot meer dan 0,9 PF waarde hebben . We voorspellen dat alle lampen en armaturen met een lager dan 0,9 PF binnenkort zal worden afgebouwd .
Tabel 2 . Vergelijking van verschillende driver architecturen .
driver topologieën
Gezien onze PF eis , zullen wij een aantal stuurprogramma topologieën die kunnen worden gebruikt in gesloten SSL producten, samen met de kosten en prestaties implicaties van elk. De verschillende benaderingen zijn samengevat in Tabel 2 . We introduceren ook een nieuwe regeling grote rimpel verlagen dat gebruikelijk is in een stadium chauffeurs.
Fig. 2 . Passieve of vallei -fill PFC fase plus een DC / DC - converter fase in een LED-driver .
Fig. 2 . Passieve of vallei -fill PFC fase plus een DC / DC - converter fase in een LED-driver .
Passieve PFC plus schakelen DC / DC . Figuur 2 . Toont een twee-traps ontwerp dat bestaat uit een passieve PFC stadium samen met een omschakeling DC / DC converter tweede fase . Deze structuur wordt veel gebruikt in de low-cost offline adapters en opladers. De PF ontwerp wordt vaak aangeduid als vallei vullen als condensatoren houden de uitgang van het vallen te laag niveau . Dankzij de vallei vullen circuit en het grootste condensator , de huidige golf van deze regeling is klein en gemakkelijk te controleren. het nadeel van de passieve regeling dat het niet geschikt voor hogere macht over 20W vanwege inherent slechte PF elektromagnetische compatibiliteit ( EMC ) problemen bij hogere vermogens . Dergelijke ontwerpen zijn niet in staat het passeren van de IEC EN61000 - 3-2 ( Harmonische huidige emissietest ) klasse C standaard . In Daarnaast is de passieve regeling is niet geschikt om brede universele ingangsspanning reeksen zoals 100-240 VAC bereiken .
Figuur 3 . . Eentraps actieve PFC driver architectuur .
Figuur 3 . . Eentraps actieve PFC driver architectuur .
Eentraps actieve PFC . De eentraps aanpak met actieve PFC die is afgebeeld in Fig. 3 is een algemeen aanvaarde topologie voor een breed ingangsbereik LED-drivers . De topologie levert goede energie - conversie-efficiëntie en PF waarde met brede lading aanbod ook . het nadeel is de hoge rimpel die leidt tot zichtbare of onzichtbare 100-120 Hz flikkering Goede ontwerpen kunt de huidige rimpel te verminderen tot een relatief lage waarde ; . maar de rimpel is normaal gesproken nog steeds hoger dan de vorige twee -traps regeling . een interessante eigenschap van de eentraps topologie is dat de rimpel sterk wordt beïnvloed door de verschillende spanning en stroom kenmerken die specifiek zijn voor elke LED- belasting zijn . Driver ontwerpers zijn op zoek naar betere manieren om de rimpel in de single- stage design te controleren .
Figuur 4 . . Active PFC fase plus een DC / DC - converter fase in een LED-driver .
Figuur 4 . . Active PFC fase plus een DC / DC - converter fase in een LED-driver .
Actieve PFC plus schakelen DC / DC . Een manier om de uitgang rimpel lossen is een actieve tweede fase toe dat de actieve PFC trap . Dergelijke topologie is afgebeeld in Fig. 4 met de toevoeging van een DC / DC converter stage . Maar de extra DC / DC stadium van de bestuurder komt met een kostenstijging van 15-20 % . deze schakeling aanzienlijk verlaagt de uitgangsstroom rimpel en maakt de uitvoer bijna een ideale DC ten koste van verlies van 2-3 % rendement . Bovendien is deze structuur kan het grootste deel van het vermogen vereist binnenshuis en wordt veel gebruikt .
Eentraps PFC en rimpelspanningonderdrukker . Idealiter zou SSL systeemontwikkelaars een methode goedkopere voorkeur aan de uitgang rimpel te verminderen , en dat zou ons terug naar een single- stage benadering te brengen . Gelukkig is er nog een goede oplossing voor het verlagen van de output stroomrimpel met een circuit dat is veel eenvoudiger dan een omschakeling DC / DC het podium. Je kunt segment een single- stage design met een relatief eenvoudige lineaire rimpel - dempelement zoals die afgebeeld in Fig. 5 .
De gemodificeerde - eentraps topologie maakt gebruik van een uniek ontworpen lineaire regelaar , die sterk kan verminderen de uitgangsstroom rimpel van eentraps PFC constante stroom uitgang met slechts 2-3 % rendement verlies . De aanpak biedt extra voordelen . Een switching DC toevoegen / DC stadium bestuurder handicaps de EMC in de meeste gevallen , het toevoegen van het lineaire regelaar niet . Hoe beter EMC verbinding betekent de rimpelspanningonderdrukker flexibel worden gebruikt met bestaande eentraps LED-drivers door SSL fabrikanten . toevoeging van het circuit aan de uitgang is veel efficiënter dan het kopen van een andere bestuurder of schakelende DC / DC converter om veel betere lichtopbrengst te krijgen.
Deze rimpelspanningonderdrukker schakeling in serie wordt gebruikt met de eentraps PFC output en bestaat voornamelijk uit een MOSFET een stroom sensing weerstand en een foutversterker . Het sensing weerstand krijgt de rimpelspanning signaal en indien de rimpel groter is dan de instelwaarde , de output van de fout versterker past de spanning op de MOSFET zodat de rimpel kleiner . Deze eenvoudige componenten kunnen worden ingekapseld in een zeer klein pakket of zelfs in een geïntegreerde schakeling .
Als de LED verlichtingsindustrie ontwikkelt, kan functies zoals hoge efficiency en een lange levensduur alleen niet aan de markt . Mensen zijn op zoek naar een betere verlichting omgeving , vooral wanneer het wordt gerelateerd aan de gezondheid . Voor bepaalde plaatsen, zoals kantoren en woonkamers , eliminatie van de strobe flicker is nog belangrijker .
Er zijn meerdere manieren om een goede gelijkstroom maakt met lage rimpel LED's rijden , elke methode heeft voordelen en nadelen Het belangrijkste voordeel van de rimpelspanningonderdrukker is dat het een zeer eenvoudige en flexibele manier om de flikkering van het ontwerp dat we reeds verminderen . bij een minimale en zeer redelijke kosten .
More info you can visit：http://www.lighting-ledlight.com/index.php/category/led-street-light/
Vervanging van traditionele gloeilampen en tl- lampen met een efficiëntere en duurzamere LED - gebaseerde solid- state lighting ( SSL ) is een onmiskenbare trend in de verlichtingsindustrie . Aangezien SSL armaturen rechtstreeks zijn aangesloten op de AC- lijn , zoals met legacy verlichting , bestaat het risico dat 100 Hz of 120 Hz flikkering kunnen optreden als gevolg van het rijden rimpelspanning aan de uitgang van de voeding is . Flicker kunnen mensen ongemakkelijk , waardoor hoofdpijn en andere kwalen maken terwijl het menselijk oog de flikkering niet kan detecteren. zorgvuldige LED-driver ontwerp kan flikkeren minimaliseren en ervoor te zorgen dat SSL levert op zijn energie - efficiëntie belofte door middel van brede implementatie.
Inderdaad, led street lights price en armatuur fabrikanten willen graag de flikkering probleem op te lossen , en ze zijn grotendeels wendde zich tot de fabrikanten bestuurder voor een oplossing, omdat uiteindelijk de bestuurder bepaalt de mate van flikkering . Dit artikel zal de oorzaak en karakterisering van flikkering uitleggen , beschrijven hoe het voorkomt in LED-verlichting , en uitleggen hoe ingenieurs kan inruilen verschillende driver topologieën in een poging om de juiste kosten / baten combinatie te vinden . We zullen een rimpelspanningonderdrukker circuit dat is een kosteneffectieve en flexibele manier van uitvoering trillingsvrije LED beschrijven verlichting .
marktverwachtingen
Het is een goed erkend trend die LED-verlichting zal legacy bronnen vervangen , waaronder gloeilampen en tl-lampen en buizen in de komende jaren . Omdat LED is een nieuwe generatie lichtbron met elektronische roots , de markt verwacht dat niet alleen de hogere SSL -systeem - level werkzaamheid , maar ook een betere verlichting milieu .
Net als de erfenis verlichting technologieën , maar de meeste LED-lampen zijn direct aangesloten op het lichtnet , dat werkt op 50 of 60 Hz in verschillende wereldregio's . Zelfs na correctie voor frequenties van 100 of 120 Hz , kan ieder - lijn verbonden flikkering detecteerbaar zijn het menselijk oog door de relatief lage frequenties betrokken . Inderdaad, de gerectificeerde regel kan leiden tot strobe flikkeren , die de eerder genoemde nood bij mensen kunnen veroorzaken .
In het bijzonder , LED-driver ontwerpen die afhankelijk zijn van een eentraps architectuur om zowel Power Factor Correction ( PFC ) en uitgaande stroom verwerken zijn bijzonder gevoelig voor flikkeren . Onder andere oorzaken , wordt flikkering beïnvloed door de LED- rimpelspanning . Maar er zijn tal van methoden om het probleem , waaronder een rimpelspanningonderdrukker circuit te elimineren . SSL product ontwikkelaars nodig hebben om de aanpak te evalueren en te kiezen voor een driver die de applicatie-eisen in kosten en prestaties voldoen . verschillende niveaus van flikkering aanvaardbaar zijn in verschillende toepassingen . een ontwerp van het systeem , dat is onaanvaardbaar in indoor toepassingen vanwege flikkeren kan presteren prima in een openlucht straat of terreinverlichting rol .
Het effect van flikkeringen
Laten we nu onderzoeken flikkeren Volgens de nota " Een overzicht van de literatuur over licht flikkeren : Ergonomie , biologische eigenschappen , de potentiële gevolgen voor de gezondheid , en methoden ." Dat in 2010 werd gepubliceerd door het Institute of Electrical and Electronic Engineers ( IEEE ) , licht flikkeren frequentie in de 3-70 Hz - assortiment is zeer waarneembaar door mensen en dit kan ze erg ongemakkelijk ( http://bit.ly/1iL2vjq en http://bit.ly/NAtjXq ) . Zelfs repetitieve zwaailichten en statische herhalende geometrische patronen kunnen aanvallen bij deze individuen induceren , en het optreden bedraagt ongeveer 0,025% . kan dit type trilling gemakkelijk opgelost worden door de bestuurder , en normaal beschouwen we de bestuurder instabiel als dat soort frequentie kan worden gezien in de output stroomrimpel golfvorm.
Nu echter, mensen beginnen om meer aandacht te besteden aan de blootstelling op lange termijn onder hogere frequentie flikkering in de 70-160 Hz heeft . Dergelijke flikkeren kan malaise , hoofdpijn en slechtziendheid veroorzaken . Sommige onderzoekers beweren zelfs het netvlies kan voelen flikkeren tot 200 Hz , maar tests hebben aangetoond dat boven 160 Hz de gezondheidseffecten van flikkering zijn verwaarloosbaar. Vanwege de eerder genoemde verholpen lijn frequenties van 100 en 120 Hz , zullen we ons richten op het verminderen van flikkering in dat bereik hier . en in werkelijkheid de menselijke gezondheidseffecten van 100 - of 120 - Hz flikkering is een functie van niet alleen de frequentie maar ook de fysieke en fysiologische factoren .
Het definiëren van flikkering
Moeten we eerst begrijpen hoe flikkeren wordt gekenmerkt . De Illuminating Engineering Society of North America ( IESNA ) vrijgegeven van de definitie van " procent flikkeren " en " flicker index " in de negende editie van De IESNA Lighting Handbook. Figuur 1 . Toont hoe de metrics gedefinieerd .
Figuur 1 . . IES definieert flikkeren index .
Figuur 1 . . IES definieert flikkeren index .
Percentage flikkering is een relatieve maat voor de cyclische variatie van de output van een lichtbron ( dwz procent modulatie ) . Dit wordt ook wel aangeduid als de " modulatie . " Verwijzend naar figuur 1 . Je procent flikkering berekenen van de maximale ( a ) en minimum ( B ) lichtopbrengst niveaus . verdeel de som van a en B door het verschil van de twee tot een percentage verkrijgen .
Flicker index is gedefinieerd in de IESNA handboek als een " betrouwbare relatieve maat van de cyclische variatie in de productie van verschillende bronnen op een gegeven macht frequentie. Het houdt rekening met de golfvorm van de lichtopbrengst als de amplitude . " The flicker index veronderstelt waarden van 0 tot 1.0, met 0 voor een constante lichtopbrengst . hogere waarden duiden op een verhoogde kans opvallende licht flikkeren , en stroboscopisch effect . opnieuw verwijzend naar figuur 1 . , de index berekend door deling Area 1 door de som van Area 1 en zone 2 .
Tabel 1 . Samenvatting van procent flikkeren en flikkering index voor lichtbronnen .
Zoals eerder vermeld , naast de frequentie , de trilling index heeft een significant effect op hoe licht maakt mensen voelen . Hogere trilling index betekent meer gevoeligheid voor het menselijk oog en een slechtere comfort . Tabel 1 toont de typische flikkering index van ander licht motoren volgens de krant " de evaluatie van flikkering in LED-armaturen " geschreven door Michael Grather , voorzitter van Armatuur Testen Laboratory , en geplaatst op de Raad voor optische straling metingen ( CORM ) website.
SSL lichtbron uitgang
Na gedefinieerd flikkeren, laten we eens kijken hoe een LED lichtbron actief is. LED lichtopbrengst is vrijwel lineair met de stroom van de regelaar . Kennisnemen van elke high - power LED data sheet en je kunt de lineariteit zien in grafieken die plot vooruit huidige opzichte van lichtstroom . Dergelijke een perceel maakt het heel duidelijk dat de stroom van de regelaar is een kritische bron van LED-licht flikkeren , en constante stroomtoevoer is de primaire taak van de LED-driver .
Wanneer we praten 100-120 Hz flikkering , meestal zijn we gericht op binnenverlichting toepassingen . Er zijn nogal wat led street lighting Manufacturer regelingen voor binnenverlichting die een constante stroom kan leveren . Bijvoorbeeld eenvoudige stroombegrenzende weerstanden , lineaire halfgeleider regelgeving , en schakelen pulse - width modulation ( PWM ) regulering volgende AC rectificatie zijn allemaal mogelijkheden . Maar die regelingen zijn buiten het bereik van deze omdat ze niet in staat om de macht (PF ) nodig voor indoor commerciële toepassingen. Typisch , commerciële toepassingen vereisen een PF groter dan 0,9 . Steeds meer landen en normen verenigingen zoals Energy Star en DesignLights Consortium ( DLC ) vereisen verlichting tot meer dan 0,9 PF waarde hebben . We voorspellen dat alle lampen en armaturen met een lager dan 0,9 PF binnenkort zal worden afgebouwd .
Tabel 2 . Vergelijking van verschillende driver architecturen .
driver topologieën
Gezien onze PF eis , zullen wij een aantal stuurprogramma topologieën die kunnen worden gebruikt in gesloten SSL producten, samen met de kosten en prestaties implicaties van elk. De verschillende benaderingen zijn samengevat in Tabel 2 . We introduceren ook een nieuwe regeling grote rimpel verlagen dat gebruikelijk is in een stadium chauffeurs.
Fig. 2 . Passieve of vallei -fill PFC fase plus een DC / DC - converter fase in een LED-driver .
Fig. 2 . Passieve of vallei -fill PFC fase plus een DC / DC - converter fase in een LED-driver .
Passieve PFC plus schakelen DC / DC . Figuur 2 . Toont een twee-traps ontwerp dat bestaat uit een passieve PFC stadium samen met een omschakeling DC / DC converter tweede fase . Deze structuur wordt veel gebruikt in de low-cost offline adapters en opladers. De PF ontwerp wordt vaak aangeduid als vallei vullen als condensatoren houden de uitgang van het vallen te laag niveau . Dankzij de vallei vullen circuit en het grootste condensator , de huidige golf van deze regeling is klein en gemakkelijk te controleren. het nadeel van de passieve regeling dat het niet geschikt voor hogere macht over 20W vanwege inherent slechte PF elektromagnetische compatibiliteit ( EMC ) problemen bij hogere vermogens . Dergelijke ontwerpen zijn niet in staat het passeren van de IEC EN61000 - 3-2 ( Harmonische huidige emissietest ) klasse C standaard . In Daarnaast is de passieve regeling is niet geschikt om brede universele ingangsspanning reeksen zoals 100-240 VAC bereiken .
Figuur 3 . . Eentraps actieve PFC driver architectuur .
Figuur 3 . . Eentraps actieve PFC driver architectuur .
Eentraps actieve PFC . De eentraps aanpak met actieve PFC die is afgebeeld in Fig. 3 is een algemeen aanvaarde topologie voor een breed ingangsbereik LED-drivers . De topologie levert goede energie - conversie-efficiëntie en PF waarde met brede lading aanbod ook . het nadeel is de hoge rimpel die leidt tot zichtbare of onzichtbare 100-120 Hz flikkering Goede ontwerpen kunt de huidige rimpel te verminderen tot een relatief lage waarde ; . maar de rimpel is normaal gesproken nog steeds hoger dan de vorige twee -traps regeling . een interessante eigenschap van de eentraps topologie is dat de rimpel sterk wordt beïnvloed door de verschillende spanning en stroom kenmerken die specifiek zijn voor elke LED- belasting zijn . Driver ontwerpers zijn op zoek naar betere manieren om de rimpel in de single- stage design te controleren .
Figuur 4 . . Active PFC fase plus een DC / DC - converter fase in een LED-driver .
Figuur 4 . . Active PFC fase plus een DC / DC - converter fase in een LED-driver .
Actieve PFC plus schakelen DC / DC . Een manier om de uitgang rimpel lossen is een actieve tweede fase toe dat de actieve PFC trap . Dergelijke topologie is afgebeeld in Fig. 4 met de toevoeging van een DC / DC converter stage . Maar de extra DC / DC stadium van de bestuurder komt met een kostenstijging van 15-20 % . deze schakeling aanzienlijk verlaagt de uitgangsstroom rimpel en maakt de uitvoer bijna een ideale DC ten koste van verlies van 2-3 % rendement . Bovendien is deze structuur kan het grootste deel van het vermogen vereist binnenshuis en wordt veel gebruikt .
Eentraps PFC en rimpelspanningonderdrukker . Idealiter zou SSL systeemontwikkelaars een methode goedkopere voorkeur aan de uitgang rimpel te verminderen , en dat zou ons terug naar een single- stage benadering te brengen . Gelukkig is er nog een goede oplossing voor het verlagen van de output stroomrimpel met een circuit dat is veel eenvoudiger dan een omschakeling DC / DC het podium. Je kunt segment een single- stage design met een relatief eenvoudige lineaire rimpel - dempelement zoals die afgebeeld in Fig. 5 .
De gemodificeerde - eentraps topologie maakt gebruik van een uniek ontworpen lineaire regelaar , die sterk kan verminderen de uitgangsstroom rimpel van eentraps PFC constante stroom uitgang met slechts 2-3 % rendement verlies . De aanpak biedt extra voordelen . Een switching DC toevoegen / DC stadium bestuurder handicaps de EMC in de meeste gevallen , het toevoegen van het lineaire regelaar niet . Hoe beter EMC verbinding betekent de rimpelspanningonderdrukker flexibel worden gebruikt met bestaande eentraps LED-drivers door SSL fabrikanten . toevoeging van het circuit aan de uitgang is veel efficiënter dan het kopen van een andere bestuurder of schakelende DC / DC converter om veel betere lichtopbrengst te krijgen.
Deze rimpelspanningonderdrukker schakeling in serie wordt gebruikt met de eentraps PFC output en bestaat voornamelijk uit een MOSFET een stroom sensing weerstand en een foutversterker . Het sensing weerstand krijgt de rimpelspanning signaal en indien de rimpel groter is dan de instelwaarde , de output van de fout versterker past de spanning op de MOSFET zodat de rimpel kleiner . Deze eenvoudige componenten kunnen worden ingekapseld in een zeer klein pakket of zelfs in een geïntegreerde schakeling .
Als de LED verlichtingsindustrie ontwikkelt, kan functies zoals hoge efficiency en een lange levensduur alleen niet aan de markt . Mensen zijn op zoek naar een betere verlichting omgeving , vooral wanneer het wordt gerelateerd aan de gezondheid . Voor bepaalde plaatsen, zoals kantoren en woonkamers , eliminatie van de strobe flicker is nog belangrijker .
Er zijn meerdere manieren om een goede gelijkstroom maakt met lage rimpel LED's rijden , elke methode heeft voordelen en nadelen Het belangrijkste voordeel van de rimpelspanningonderdrukker is dat het een zeer eenvoudige en flexibele manier om de flikkering van het ontwerp dat we reeds verminderen . bij een minimale en zeer redelijke kosten .
More info you can visit：http://www.lighting-ledlight.com/index.php/category/led-street-light/
Philips and Green Sense Farms harness LEDs for horticulture
Koninklijke Philips heeft een samenwerkingsverband met Green Sense Farms tot massale indoor commerciële landbouw -installaties die gebruik maken van LED-verlichting om de productiviteit te maximaliseren planten ontwikkelen aangekondigd . De bedrijven geloven dat afgestemd solid- state lighting ( SSL ) 20-25 oogsten per jaar kunnen opleveren tijdens het gebruik van 85% minder energie dan indoor tuinbouw installaties die erfenis verlichting te gebruiken .
Green Sense Farms is gerenoveerd 14 25 -ft - hoge teelt torens in twee klimaatkamers met Philips Lighting LED-producten .
Green Sense Farms is gerenoveerd 14 25 -ft - hoge teelt torens in twee klimaatkamers met Philips Lighting LED-producten .
Zoals we eerder hebben behandeld , kan LED-verlichting een aantal voordelen op in de tuinbouw . Precieze levering van specifieke golflengten kunnen plantaardige productie op te voeren en LED-verlichting biedt de flexibiliteit in termen van mechanische form factor voor de productie hogere dichtheid fabriek in commerciële landbouw instellingen . Er zijn ook voordelen aan cree xsp series led street light dan direct versnellen ontwikkeling van de plant , zoals Valoya in Nederland toegenomen bee activiteit onder SSL die resulteert in verbeterde tomatenteelt heeft gedocumenteerd .
De laatste tuinbouw nieuws van Philips gaat om een grote commerciële groeier in Green Sense Farms gevestigd in Chicago , Illinois gebied . De boerderij hoopt dat LED's kunnen hen helpen produceren meer oogsten per jaar , gebruiken minder energie , en zoek groeiende activiteiten in de buurt van de consument , waardoor het verminderen van de transport kosten om voedsel op de markt , terwijl het leveren van superieure frisser producten aan de consument .
Green Sense Farms is gerenoveerd 14 25 -ft - hoge teelt torens in twee klimaatkamers met Philips Lighting LED-producten . De installatie omvat een een - miljoen - FT3 groeiende ruimte waar de boerderij zullen profiteren van de low-profile en warmte - vrij aspecten led-verlichting planten stapelen in een hoge dichtheid fashion .
"Door de groei van onze gewassen verticaal , zijn we in staat om meer planten per hectare dan we in een boerderij veld , wat resulteert in meer oogsten per jaar zou moeten pakken ", zegt Robert Colangelo , stichtend boer / voorzitter van Green Sense Farms . " Wij produceren weinig afval, geen landbouw- afvoer , en een minimale uitstoot van broeikasgassen , omdat het voedsel wordt verbouwd , waar het wordt verbruikt . "
De LED- installatie zal een hefboomeffect Philips tuinbouw onderzoek. " Verschillende soorten planten hebben verschillende licht behoeften en werken met vooruitstrevende telers als Green Sense Farms , is Philips het opbouwen van een database van lichte recepten voor verschillende plantensoorten ", zegt Udo van Slooten , directeur . van de tuinbouw bij Philips ' Green Sense Farms is met behulp van verticale hydrocultuur technologie met Philips LED groeilicht , zodat ze doen wat geen enkele andere teler kan doen : . Zorg voor een consistente hoeveelheid van hoge kwaliteit te produceren , het hele jaar door "
De partners zijn van mening dat dergelijke operaties essentieel in het voeden van een snel groeiende wereldbevolking basis zal zijn. De Verenigde Naties projecten die wereldbevolking zal toenemen met 2,5 miljard mensen in 2050 . Bovendien wordt 80 % van de bevolking in steden woont , het maken van high - density stedelijke boerderijen een noodzaak .
Green Sense Farms hoopt LED - verlichte groeiende activiteiten gelegen samenvalt met faciliteiten zoals universiteiten , ziekenhuizen complexen en militaire bases aan lokale producten productie bieden bouwen . "Door onze gezamenlijke inspanningen van R & D met Philips , we blijven innoveren en een perfecte led street light with solar panel voor binnen groeiende systemen die de fotosynthese van planten kunnen maximaliseren , terwijl het minimaliseren van energiegebruik voor de meest lekkere en voedzame groenten geteeld op een duurzame manier , "zei Colangelo .
Een artikel van consultancy Uitbesteed Innovatie gekwantificeerd een aantal van de voordelen van LED-verlichting in de tuinbouw en ook geïdentificeerd kernactiviteiten voor de industrie voor de toekomst. Osram heeft ook geschreven over het onderwerp van tuned LED spectrum voor de tuinbouw en andere life - science toepassingen .
More info you can visit:http://www.lead-lighting.com/products/sid109-1.htm
Green Sense Farms is gerenoveerd 14 25 -ft - hoge teelt torens in twee klimaatkamers met Philips Lighting LED-producten .
Green Sense Farms is gerenoveerd 14 25 -ft - hoge teelt torens in twee klimaatkamers met Philips Lighting LED-producten .
Zoals we eerder hebben behandeld , kan LED-verlichting een aantal voordelen op in de tuinbouw . Precieze levering van specifieke golflengten kunnen plantaardige productie op te voeren en LED-verlichting biedt de flexibiliteit in termen van mechanische form factor voor de productie hogere dichtheid fabriek in commerciële landbouw instellingen . Er zijn ook voordelen aan cree xsp series led street light dan direct versnellen ontwikkeling van de plant , zoals Valoya in Nederland toegenomen bee activiteit onder SSL die resulteert in verbeterde tomatenteelt heeft gedocumenteerd .
De laatste tuinbouw nieuws van Philips gaat om een grote commerciële groeier in Green Sense Farms gevestigd in Chicago , Illinois gebied . De boerderij hoopt dat LED's kunnen hen helpen produceren meer oogsten per jaar , gebruiken minder energie , en zoek groeiende activiteiten in de buurt van de consument , waardoor het verminderen van de transport kosten om voedsel op de markt , terwijl het leveren van superieure frisser producten aan de consument .
Green Sense Farms is gerenoveerd 14 25 -ft - hoge teelt torens in twee klimaatkamers met Philips Lighting LED-producten . De installatie omvat een een - miljoen - FT3 groeiende ruimte waar de boerderij zullen profiteren van de low-profile en warmte - vrij aspecten led-verlichting planten stapelen in een hoge dichtheid fashion .
"Door de groei van onze gewassen verticaal , zijn we in staat om meer planten per hectare dan we in een boerderij veld , wat resulteert in meer oogsten per jaar zou moeten pakken ", zegt Robert Colangelo , stichtend boer / voorzitter van Green Sense Farms . " Wij produceren weinig afval, geen landbouw- afvoer , en een minimale uitstoot van broeikasgassen , omdat het voedsel wordt verbouwd , waar het wordt verbruikt . "
De LED- installatie zal een hefboomeffect Philips tuinbouw onderzoek. " Verschillende soorten planten hebben verschillende licht behoeften en werken met vooruitstrevende telers als Green Sense Farms , is Philips het opbouwen van een database van lichte recepten voor verschillende plantensoorten ", zegt Udo van Slooten , directeur . van de tuinbouw bij Philips ' Green Sense Farms is met behulp van verticale hydrocultuur technologie met Philips LED groeilicht , zodat ze doen wat geen enkele andere teler kan doen : . Zorg voor een consistente hoeveelheid van hoge kwaliteit te produceren , het hele jaar door "
De partners zijn van mening dat dergelijke operaties essentieel in het voeden van een snel groeiende wereldbevolking basis zal zijn. De Verenigde Naties projecten die wereldbevolking zal toenemen met 2,5 miljard mensen in 2050 . Bovendien wordt 80 % van de bevolking in steden woont , het maken van high - density stedelijke boerderijen een noodzaak .
Green Sense Farms hoopt LED - verlichte groeiende activiteiten gelegen samenvalt met faciliteiten zoals universiteiten , ziekenhuizen complexen en militaire bases aan lokale producten productie bieden bouwen . "Door onze gezamenlijke inspanningen van R & D met Philips , we blijven innoveren en een perfecte led street light with solar panel voor binnen groeiende systemen die de fotosynthese van planten kunnen maximaliseren , terwijl het minimaliseren van energiegebruik voor de meest lekkere en voedzame groenten geteeld op een duurzame manier , "zei Colangelo .
Een artikel van consultancy Uitbesteed Innovatie gekwantificeerd een aantal van de voordelen van LED-verlichting in de tuinbouw en ook geïdentificeerd kernactiviteiten voor de industrie voor de toekomst. Osram heeft ook geschreven over het onderwerp van tuned LED spectrum voor de tuinbouw en andere life - science toepassingen .
More info you can visit:http://www.lead-lighting.com/products/sid109-1.htm
TI adds LED driver ICs for automotive forward and rear lighting
Texas Instruments ( TI ) heeft aangekondigd de TPS92630 - Q1 en TPS92602 - Q1 families van LED-driver IC's gericht achter - en voorwaarts gerichte automotive verlichting , respectievelijk . Zowel van de driver IC families voorzien van high-side , stroom -sense - gebaseerde dimmen mogelijkheden samen met fout - detectie functies bedoeld om de verschillende auto - centric regelgeving over de hele wereld te voldoen.
Gerelateerd artikel : Osram introduceert twee nieuwe LED- families voor auto koplampen
LED's zijn steeds de lichtbron van de keuze voor automotive verlichting als gevolg van zowel de efficiëntie en duurzaamheid . Maar de automotive toepassing is onderworpen aan strenge regelgevende instanties over de hele wereld . We hadden zowel betrekking op onderwerpen in een hoofdartikel van vorig jaar.
TI voegt LED-driver IC's voor de automobielindustrie naar voren en achter verlichting
Op naar de TI nieuws , is de TPS92630 - Q1 IC bedoeld voor naar achteren gerichte toepassingen zoals richtingaanwijzers , achteruitrijlampen en remlichten . De IC biedt de mogelijkheid om een enkele led high bay light price lukt via een korte of gesloten circuit automatisch te detecteren , waardoor de totale achter - verlichting aan blijven werken , waardoor de wettelijke eisen voldoen in veel regio's .
Autoverlichting ontwikkelaars kunnen combineren maar liefst 15 van de TPS92630 - Q1 IC's op een enkele bus om een array van LED's op basis van eenvoudige controle logica met geen vereiste voor een microcontroller om storingen of fouten af te handelen beheersen . De fail-safe functies geïntegreerd in de IC resultaat in een goedkopere stuklijsten en eenvoudiger realiseren op een printplaat (PCB ) . Bovendien is de IC ook een programmeerbare thermische fold -back functie die LED flikkeren voorkomt in een storing .
Voor voren gerichte toepassingen , de TPS92602 - Q1 IC is een twee - kanaals schakelen driver die bok, boost , buck-boost , SEPIC , en flyback converter topologieën op een kanaal -voor- kanaal basis kan ondersteunen . De flexibiliteit maakt het mogelijk verlichting ontwikkelaars het ontwikkelen van een eenvoudiger PCB met dezelfde IC uitvoering van de topologie vereist voor specifieke lichtfuncties .
Gerelateerd artikel : Audi verhoogt functionaliteit hoofdlamp met LED's en intelligente controle
De TPS92602 - Q1 kan zowel lineaire dimmen en pulse - width modulation ( PWM ) verduistering met laatstgenoemde op basis van de huidige -sense technologie ondersteunen . Een geïntegreerde diagnostische mogelijkheden kunnen uitvallen of fouten mee aan de body- besturingselektronica , die voldoen aan vele wettelijke eisen. het IC heeft ook de mogelijkheid om automatisch te wisselen van constante stroom modus met constante spanning modus als een led high bay light for sale open optreedt , waardoor wordt gewaarborgd andere LED's werken op een ononderbroken wijze.
Voor ontwikkelaars die willen experimenteren met de nieuwe driver IC's , is TI ook het aanbieden van de evaluatie modules voor zowel van het product families . De TPS92630 EVM verkoopt voor $ 99 en omvat een drie - kanaals uitvoering staat PWM en analoog dimmen met drie Osram Opto Semiconductor LEDs gedreven in serie op elk kanaal . de TPS92602 EVM bestaat uit een twee - kanaals uitvoering met afzonderlijke verordening lussen die kan werken in een constante spanning of stroom modes en verkoopt voor $ 115 . TI zal ook leveren SPICE modellen voor de IC's om de bestuurder ontwerp te vereenvoudigen proces .
more info you can visit：http://www.lighting-ledlight.com/index.php/category/led-high-bay/
Gerelateerd artikel : Osram introduceert twee nieuwe LED- families voor auto koplampen
LED's zijn steeds de lichtbron van de keuze voor automotive verlichting als gevolg van zowel de efficiëntie en duurzaamheid . Maar de automotive toepassing is onderworpen aan strenge regelgevende instanties over de hele wereld . We hadden zowel betrekking op onderwerpen in een hoofdartikel van vorig jaar.
TI voegt LED-driver IC's voor de automobielindustrie naar voren en achter verlichting
Op naar de TI nieuws , is de TPS92630 - Q1 IC bedoeld voor naar achteren gerichte toepassingen zoals richtingaanwijzers , achteruitrijlampen en remlichten . De IC biedt de mogelijkheid om een enkele led high bay light price lukt via een korte of gesloten circuit automatisch te detecteren , waardoor de totale achter - verlichting aan blijven werken , waardoor de wettelijke eisen voldoen in veel regio's .
Autoverlichting ontwikkelaars kunnen combineren maar liefst 15 van de TPS92630 - Q1 IC's op een enkele bus om een array van LED's op basis van eenvoudige controle logica met geen vereiste voor een microcontroller om storingen of fouten af te handelen beheersen . De fail-safe functies geïntegreerd in de IC resultaat in een goedkopere stuklijsten en eenvoudiger realiseren op een printplaat (PCB ) . Bovendien is de IC ook een programmeerbare thermische fold -back functie die LED flikkeren voorkomt in een storing .
Voor voren gerichte toepassingen , de TPS92602 - Q1 IC is een twee - kanaals schakelen driver die bok, boost , buck-boost , SEPIC , en flyback converter topologieën op een kanaal -voor- kanaal basis kan ondersteunen . De flexibiliteit maakt het mogelijk verlichting ontwikkelaars het ontwikkelen van een eenvoudiger PCB met dezelfde IC uitvoering van de topologie vereist voor specifieke lichtfuncties .
Gerelateerd artikel : Audi verhoogt functionaliteit hoofdlamp met LED's en intelligente controle
De TPS92602 - Q1 kan zowel lineaire dimmen en pulse - width modulation ( PWM ) verduistering met laatstgenoemde op basis van de huidige -sense technologie ondersteunen . Een geïntegreerde diagnostische mogelijkheden kunnen uitvallen of fouten mee aan de body- besturingselektronica , die voldoen aan vele wettelijke eisen. het IC heeft ook de mogelijkheid om automatisch te wisselen van constante stroom modus met constante spanning modus als een led high bay light for sale open optreedt , waardoor wordt gewaarborgd andere LED's werken op een ononderbroken wijze.
Voor ontwikkelaars die willen experimenteren met de nieuwe driver IC's , is TI ook het aanbieden van de evaluatie modules voor zowel van het product families . De TPS92630 EVM verkoopt voor $ 99 en omvat een drie - kanaals uitvoering staat PWM en analoog dimmen met drie Osram Opto Semiconductor LEDs gedreven in serie op elk kanaal . de TPS92602 EVM bestaat uit een twee - kanaals uitvoering met afzonderlijke verordening lussen die kan werken in een constante spanning of stroom modes en verkoopt voor $ 115 . TI zal ook leveren SPICE modellen voor de IC's om de bestuurder ontwerp te vereenvoudigen proces .
more info you can visit：http://www.lighting-ledlight.com/index.php/category/led-high-bay/
Cree launches 200-lm/W, 1226-lm discrete LED for directional SSL
Cree heeft de nieuwe XLamp XP - L LED familie aangekondigd in een 3.45 × 3.45 mm pakket belooft dat wat het bedrijf noemt een lid van de hoge - dichtheid groepering van LEDs een drop-in upgrade zal zorgen voor verlichting producten die de voorafgaande XP gebruiken -G/G2 LED's. de nieuwe LED's bereiken werkzaamheid niveaus zo hoog als 200 lm / W in koel wit , op een bescheiden 350 mA stroom van de snelheidsregelaar , terwijl solid- state lighting ( SSL ) productontwerpen de LED's kunnen rijden op een niveau 3A . Inderdaad, de maximale 10W LED's zijn gebaseerd op een discrete dobbelsteen en nu veel groter dan wat zou conventioneel worden beschouwd als een high-power LED .
Cree lanceert 200 lm / W , 1226 - lm discrete buy led high bay lamps voor directionele SSL
In recente aankondigingen , heeft Cree metrische wel optische controle factor ( OCF ) dat karakteriseert lichtopbrengst ten opzichte van licht - emitterende oppervlak ( LES ) gebied benadrukt. Het bedrijf introduceerde de OCF concept met de high-density chip -on-board ( COB ) LED's in februari vervolgens aangekondigd , Cree vervolgens aangeprezen OCF in de discrete XB - H LED die 2,5 mm per zijde meet Degenen aankondigingen samen met de XP - L versie maken allemaal deel uit van wat Cree noemt het high-density aanbod - .. LED's die zijn vooral van toepassing voor gerichte verlichting omdat het gemakkelijker in een SSL- product aan de balk bedienen vanaf een kleinere bron .
Cree vergeleken de XP - L LEDs bestaande XP - G2 LED's in een prototypische 30 mm reflectorlamp ontwerp dat in alle gevallen omvat vier LED's in serie . Meer LED's in dit geval aangedreven met een relatief lagere stroom creëert de beste balans lumen output en werkzaamheid.
Een SSL fabrikant kan een ontwerp upgraden naar de nieuwe LED en realiseren aanzienlijke winst in lichtopbrengst en werkzaamheid. De XP - G2 bijvoorbeeld levert 912 lm bij 75 lm / W bij het rijden bij 1A . De XP - L versie levert een verbetering van 30 % in lichtopbrengst van 1188 lm, en iets beter dan een 30 % werkzaamheid winst op 98 lm / W. Bovendien is de nieuwe LED's zorgen voor een verbetering van 31% in het midden balk kaars vermogen ( CBCP ) .
" We zijn enthousiast over de nieuwe XLamp XP - L LED omdat de next- level prestaties stelt ons in staat om de volgende generatie van lichtopbrengst en werkzaamheid voor onze gerichte verlichting producten te creëren , " aldus Mike Joye , voorzitter, Auroralight . "Sinds XP - L maakt gebruik van de bestaande XP footprint , kunnen we ons product line-up snel en zonder de last van de toegenomen ontwikkeling van de tijd en de kosten die men zou verwachten voor zo'n belangrijke prestatieverbetering te breiden. "
Als alternatief zou een fabrikant upgraden naar de nieuwe LED's , te verminderen stroom van de regelaar , en het realiseren van een nog grotere doeltreffendheid , terwijl het afstemmen van de lichtopbrengst van een eerder artikel. Inderdaad, Cree 's vergelijking bleek dat de XP - L LED -gedreven bij 700 mA kan 924 lm vermogen leveren op 111 lm / W.
Natuurlijk , de LED's bieden ook de mogelijkheid van ramping bestuurder stroom naar lichtopbrengst duwen tegen lagere effectiviteit niveaus . "We hebben veel high - power LED's alvorens te beslissen over nieuwe high - density discrete LED Cree 's ", zegt Jason Gerard , group general manager voor engineering aan Gerard Lighting Group . "high - density LED Cree 's stellen ons in staat om een kern ontwerp dat niet mogelijk was met eerdere LED's voor onze bepaald ontwerp doelen te ontwikkelen. we zijn verheugd dat we de nieuwste innovaties Cree 's kunt gebruiken om onze producten staan afgezien van alle anderen . "
Cree biedt de XP - L led high bay light supplier over het bereik van 2700K - 8300K CCT . Aan het warmere end fabrikanten 90 CRI kunt opgeven en op de koeler einde een 70 CRI opties beschikbaar . De meeste van de familie is beschikbaar op 80 CRI .
De XP - L wordt ook beschouwd als een vervolg op het product om de XP - G2 in de ogen van het Energy Star-programma . Deze erkenning betekent dat SSL fabrikanten producten kunnen indienen op basis van de nieuwe LED voor Energy Star-certificering na slechts 3000 uren van LM -80 testen .
More info you can visit:http://www.lead-lighting.com/products/sid20-1.htm
Cree lanceert 200 lm / W , 1226 - lm discrete buy led high bay lamps voor directionele SSL
In recente aankondigingen , heeft Cree metrische wel optische controle factor ( OCF ) dat karakteriseert lichtopbrengst ten opzichte van licht - emitterende oppervlak ( LES ) gebied benadrukt. Het bedrijf introduceerde de OCF concept met de high-density chip -on-board ( COB ) LED's in februari vervolgens aangekondigd , Cree vervolgens aangeprezen OCF in de discrete XB - H LED die 2,5 mm per zijde meet Degenen aankondigingen samen met de XP - L versie maken allemaal deel uit van wat Cree noemt het high-density aanbod - .. LED's die zijn vooral van toepassing voor gerichte verlichting omdat het gemakkelijker in een SSL- product aan de balk bedienen vanaf een kleinere bron .
Cree vergeleken de XP - L LEDs bestaande XP - G2 LED's in een prototypische 30 mm reflectorlamp ontwerp dat in alle gevallen omvat vier LED's in serie . Meer LED's in dit geval aangedreven met een relatief lagere stroom creëert de beste balans lumen output en werkzaamheid.
Een SSL fabrikant kan een ontwerp upgraden naar de nieuwe LED en realiseren aanzienlijke winst in lichtopbrengst en werkzaamheid. De XP - G2 bijvoorbeeld levert 912 lm bij 75 lm / W bij het rijden bij 1A . De XP - L versie levert een verbetering van 30 % in lichtopbrengst van 1188 lm, en iets beter dan een 30 % werkzaamheid winst op 98 lm / W. Bovendien is de nieuwe LED's zorgen voor een verbetering van 31% in het midden balk kaars vermogen ( CBCP ) .
" We zijn enthousiast over de nieuwe XLamp XP - L LED omdat de next- level prestaties stelt ons in staat om de volgende generatie van lichtopbrengst en werkzaamheid voor onze gerichte verlichting producten te creëren , " aldus Mike Joye , voorzitter, Auroralight . "Sinds XP - L maakt gebruik van de bestaande XP footprint , kunnen we ons product line-up snel en zonder de last van de toegenomen ontwikkeling van de tijd en de kosten die men zou verwachten voor zo'n belangrijke prestatieverbetering te breiden. "
Als alternatief zou een fabrikant upgraden naar de nieuwe LED's , te verminderen stroom van de regelaar , en het realiseren van een nog grotere doeltreffendheid , terwijl het afstemmen van de lichtopbrengst van een eerder artikel. Inderdaad, Cree 's vergelijking bleek dat de XP - L LED -gedreven bij 700 mA kan 924 lm vermogen leveren op 111 lm / W.
Natuurlijk , de LED's bieden ook de mogelijkheid van ramping bestuurder stroom naar lichtopbrengst duwen tegen lagere effectiviteit niveaus . "We hebben veel high - power LED's alvorens te beslissen over nieuwe high - density discrete LED Cree 's ", zegt Jason Gerard , group general manager voor engineering aan Gerard Lighting Group . "high - density LED Cree 's stellen ons in staat om een kern ontwerp dat niet mogelijk was met eerdere LED's voor onze bepaald ontwerp doelen te ontwikkelen. we zijn verheugd dat we de nieuwste innovaties Cree 's kunt gebruiken om onze producten staan afgezien van alle anderen . "
Cree biedt de XP - L led high bay light supplier over het bereik van 2700K - 8300K CCT . Aan het warmere end fabrikanten 90 CRI kunt opgeven en op de koeler einde een 70 CRI opties beschikbaar . De meeste van de familie is beschikbaar op 80 CRI .
De XP - L wordt ook beschouwd als een vervolg op het product om de XP - G2 in de ogen van het Energy Star-programma . Deze erkenning betekent dat SSL fabrikanten producten kunnen indienen op basis van de nieuwe LED voor Energy Star-certificering na slechts 3000 uren van LM -80 testen .
More info you can visit:http://www.lead-lighting.com/products/sid20-1.htm
Boston University sued most up and downstream LED manufacturers
Boston University heeft vele belangrijke octrooien van upstream LED-chip , onder de situatie van krappe budgetten en zelffinanciering situatie , Boston University bijna aangeklaagd alle up -en downstream led high bay lighting wholesale over de afgelopen jaren , en zelfs een aantal laptops en mobiele terminal fabrikanten .
Boston University heeft het patent van sterk isolerende monokristallijn gallium nitride dunne films ( aangeduid als 738 patenten ) , en werd exclusief bevoegd om de VS grootste LED fabrikant CREE , dus CREE aangeklaagd Nichia , BRIDGELUX en andere internationale fabrikanten .
Sinds 2012 , Boston University trad op als identiteit eiser , aangeklaagd veel bedrijven overal, met inbegrip van Taiwan Epistar , Everlight , Liteon , Harvatek en Seoul Semiconductor en Samsung , en vervolgens gebruikt de laptop en mobiele telefoon fabrikanten in 2013 , waaronder de Amerikaanse Apple en Amazon , Japans Sony , Zuid-Korea LG , evenals Taiwan Asustek , Acer en BenQ .
Boston led high bay price is in de upstream , maar ze klaagde ook veel downstream bedrijven , voor de fabrikanten van consumentenelektronica hebben naamsbekendheid , zodat ze niet betrokken willen worden , dus nadat ze beschuldigd , oefenden zij druk op de toeleveranciers , en ten slotte Boston University is in staat om zijn patenten te verdedigen.
LED-industrie biedt een interessante interpretatie , in het verleden , Boston University vroegen Cree aan de bedrijven aanklagen , maar verdedigde de commerciële belangen van Cree , voor Boston University heeft zelf geen " aanzienlijke voordelen opleveren ." Voor nu , het trok de octrooien , en aangeklaagd bedrijven zelf , eenmaal succesvol , het zal een redelijke vergoeding krijgen in de situatie van krap budget van Amerikaanse universiteiten .
more info you can visit:http://www.lighting-ledlight.com/index.php/category/led-high-bay-light/
Boston University heeft het patent van sterk isolerende monokristallijn gallium nitride dunne films ( aangeduid als 738 patenten ) , en werd exclusief bevoegd om de VS grootste LED fabrikant CREE , dus CREE aangeklaagd Nichia , BRIDGELUX en andere internationale fabrikanten .
Sinds 2012 , Boston University trad op als identiteit eiser , aangeklaagd veel bedrijven overal, met inbegrip van Taiwan Epistar , Everlight , Liteon , Harvatek en Seoul Semiconductor en Samsung , en vervolgens gebruikt de laptop en mobiele telefoon fabrikanten in 2013 , waaronder de Amerikaanse Apple en Amazon , Japans Sony , Zuid-Korea LG , evenals Taiwan Asustek , Acer en BenQ .
Boston led high bay price is in de upstream , maar ze klaagde ook veel downstream bedrijven , voor de fabrikanten van consumentenelektronica hebben naamsbekendheid , zodat ze niet betrokken willen worden , dus nadat ze beschuldigd , oefenden zij druk op de toeleveranciers , en ten slotte Boston University is in staat om zijn patenten te verdedigen.
LED-industrie biedt een interessante interpretatie , in het verleden , Boston University vroegen Cree aan de bedrijven aanklagen , maar verdedigde de commerciële belangen van Cree , voor Boston University heeft zelf geen " aanzienlijke voordelen opleveren ." Voor nu , het trok de octrooien , en aangeklaagd bedrijven zelf , eenmaal succesvol , het zal een redelijke vergoeding krijgen in de situatie van krap budget van Amerikaanse universiteiten .
more info you can visit:http://www.lighting-ledlight.com/index.php/category/led-high-bay-light/
2014年5月22日星期四
Small Size Enhances Charge Transfer in Quantum Dots
Quantum dots-tiny semiconductor crystals with diameters measured in billionths of a meter-have enormous potential for applications that make use of their ability to absorb or emit light and / or electric charges. Examples include more vividly colored light-emitting diodes (LEDs), photovoltaic solar cells, nanoscale transistors, and biosensors. But because these applications have differing-sometimes opposite-requirements, finding ways to control the dots' optical and electronic properties is crucial to their success.
In a study just published in the journal Chemical Communications, scientists at the US Department of Energy's Brookhaven National Laboratory, Stony Brook University, and Syracuse University show that shrinking the core of a quantum dot can enhance the ability of a surrounding polymer to extract electric charges generated in the dot by the absorption of light.
"Photovoltaic cells made of quantum dots paired with plastic materials like conductive polymers are far easier to make and less expensive than conventional silicon-based solar cells," said Mircea Cotlet, a physical chemist at Brookhaven's Center for Functional Nanomaterials (CFN), who led the research team. "These kinds of materials are inexpensive, easy to synthesize, and their assembly would be relatively easy.
This illustration shows two light-absorbing quantum dots (orange / red spheres) surrounded by a conducting polymer ("stick-and-ball" structure). Shrinking the core of the quantum dot enhances the transfer of electric charges called "holes" (h + ) from the quantum dot to the polymer. Quantum dots with enhanced charge transfer could find application in photovoltaic solar cells. (Photo courtesy of Brookhaven National Laboratory)
The downside is that, right now, solar devices based on silicon can't be beat in terms of efficiency. But research aimed at understanding the photovoltaic process at the nanoscale could change that.
"The ability to make and study single particles at the CFN allows us to observe and test properties that would be blurred, or averaged out, in larger samples," said Huidong Zang, a postdoctoral research fellow working with Cotlet and first author on the paper .
In a solar cell, the ideal material would absorb led street light wholesale and efficiently convert that energy into electric charges that can be easily extracted as a current. To study the details of this process, the scientists used quantum dots composed of a light-absorbing cadmium-selenium core encased in a protective zinc-sulfide shell and surrounded by a conductive polymer. They tested the ability of the polymer to extract electric charges generated when the quantum dots absorbed light, and conducted experiments using quantum dots with cores of different sizes.
"We knew from theoretical predictions that particle size should have an effect on the charge transfer with the polymer, but no one had done this as an experiment until now, and in particular at the single-particle level," Cotlet said.
When they varied the size of the quantum dot's core, the scientists found that the smaller the diameter, the more efficient and more consistent the charge transfer process.
"By using a smaller core, we increased the efficiency of the charge transfer process and narrowed the distribution of the charge-transfer rate so it was closer to the ideal with less variability," Zang said.
The scientists were exploring a particular type of charge transfer created by the movement of "holes"-areas of positive charge created by the absence of negatively charged electrons. In electronic devices, led street light supplier can be channeled just like electrons to create electric current. And in this case extracting holes had an added benefit-it increased the time that quantum dots, which turn on and off in a blinking pattern, remained in the "on" condition.
"Hole transfer inhibits blinking," Cotlet said. "It keeps the quantum dot optically active longer, which is better for the photovoltaic process, because charges can only be extracted when the quantum dot is on."
"It would be impossible to see this effect with bulk samples because you can't see the 'on' and 'off' states. When lots of quantum dots are mixed together, the signals average out. You can only see it by looking at the single nanoparticles. "
Cotlet's group had previously conducted a similar study pairing quantum dots with carbon-rich buckyballs In that study, they found the opposite effect:. Buckyballs decreased the dots "on" time while enhancing the transfer of electrons.
In other applications combing dots and polymers, such as LEDs or biosensors, scientists are looking for ways to suppress charge transfer as this process becomes detrimental.
"Knowing these fundamentals and how to control these processes at the nanoscale should help us optimize the use of quantum dots for a wide range of applications," Cotlet said.
This research was funded by the DOE Office of Science and by the Air Force Office of Scientific Research.
In a study just published in the journal Chemical Communications, scientists at the US Department of Energy's Brookhaven National Laboratory, Stony Brook University, and Syracuse University show that shrinking the core of a quantum dot can enhance the ability of a surrounding polymer to extract electric charges generated in the dot by the absorption of light.
"Photovoltaic cells made of quantum dots paired with plastic materials like conductive polymers are far easier to make and less expensive than conventional silicon-based solar cells," said Mircea Cotlet, a physical chemist at Brookhaven's Center for Functional Nanomaterials (CFN), who led the research team. "These kinds of materials are inexpensive, easy to synthesize, and their assembly would be relatively easy.
This illustration shows two light-absorbing quantum dots (orange / red spheres) surrounded by a conducting polymer ("stick-and-ball" structure). Shrinking the core of the quantum dot enhances the transfer of electric charges called "holes" (h + ) from the quantum dot to the polymer. Quantum dots with enhanced charge transfer could find application in photovoltaic solar cells. (Photo courtesy of Brookhaven National Laboratory)
The downside is that, right now, solar devices based on silicon can't be beat in terms of efficiency. But research aimed at understanding the photovoltaic process at the nanoscale could change that.
"The ability to make and study single particles at the CFN allows us to observe and test properties that would be blurred, or averaged out, in larger samples," said Huidong Zang, a postdoctoral research fellow working with Cotlet and first author on the paper .
In a solar cell, the ideal material would absorb led street light wholesale and efficiently convert that energy into electric charges that can be easily extracted as a current. To study the details of this process, the scientists used quantum dots composed of a light-absorbing cadmium-selenium core encased in a protective zinc-sulfide shell and surrounded by a conductive polymer. They tested the ability of the polymer to extract electric charges generated when the quantum dots absorbed light, and conducted experiments using quantum dots with cores of different sizes.
"We knew from theoretical predictions that particle size should have an effect on the charge transfer with the polymer, but no one had done this as an experiment until now, and in particular at the single-particle level," Cotlet said.
When they varied the size of the quantum dot's core, the scientists found that the smaller the diameter, the more efficient and more consistent the charge transfer process.
"By using a smaller core, we increased the efficiency of the charge transfer process and narrowed the distribution of the charge-transfer rate so it was closer to the ideal with less variability," Zang said.
The scientists were exploring a particular type of charge transfer created by the movement of "holes"-areas of positive charge created by the absence of negatively charged electrons. In electronic devices, led street light supplier can be channeled just like electrons to create electric current. And in this case extracting holes had an added benefit-it increased the time that quantum dots, which turn on and off in a blinking pattern, remained in the "on" condition.
"Hole transfer inhibits blinking," Cotlet said. "It keeps the quantum dot optically active longer, which is better for the photovoltaic process, because charges can only be extracted when the quantum dot is on."
"It would be impossible to see this effect with bulk samples because you can't see the 'on' and 'off' states. When lots of quantum dots are mixed together, the signals average out. You can only see it by looking at the single nanoparticles. "
Cotlet's group had previously conducted a similar study pairing quantum dots with carbon-rich buckyballs In that study, they found the opposite effect:. Buckyballs decreased the dots "on" time while enhancing the transfer of electrons.
In other applications combing dots and polymers, such as LEDs or biosensors, scientists are looking for ways to suppress charge transfer as this process becomes detrimental.
"Knowing these fundamentals and how to control these processes at the nanoscale should help us optimize the use of quantum dots for a wide range of applications," Cotlet said.
This research was funded by the DOE Office of Science and by the Air Force Office of Scientific Research.
Lighting Psychology: Cognitive and Emotional Responses to Lighting
In this white paper, Robert Davis, Director, Product Innovation & Marketing at LiteControl provides some insights on how led street light fixture designs are perceived by the brain. Davis, who holds a PhD, is a Fellow of the Illuminating Engineering Society.
The human brain. (Photo Courtesy of LiteControl)
Stimulus -. Response It serves as the foundation of any basic Psychology class It defines our relationship to the world around us From Pavlov's dogs salivating at the sound of a bell to you quickly pulling your finger away from a hot pan, familiar examples of.. an involuntary response to a stimulus abound And it all seems pretty simple -. present this sort of stimulus, and you can count on a certain response.
Lighting practitioners work hard at getting the stimulus right to attain a desired response Historically, that has in large part meant a detailed and careful characterization of visual tasks under different lighting conditions -. The stimulus - and a variety of important methods for measuring visual performance as those conditions are varied - the response From Blackwell's Visibility Level to Rea's models of Relative Visual Performance, we have learned much about the nature of the stimulus-response relationships relating to human visual performance..
But what about those responses to lighting that go beyond considerations of task performance? Lighting can help create excitement in a themed environment. Lighting can help a person navigate through a new space. Lighting can help to bring about a sense of calm and peacefulness in a sacred setting. Lighting can help to add mystery in a theatrical production. And, lighting can cause us to strongly dislike a room which we would otherwise find appealing. How does our mind process the visual stimulus to produce these sorts of responses? What do we understand today about the way that we light buildings that enables us to link the stimulus of a lighted environment to the full array of cognitive and emotional human responses?
The answer, unfortunately, is - not much The depth and wealth of our research and knowledge in lighting's impacts on visual task performance only underscores the dearth of information on these other aspects of human responses to lighting..
But we do know a few things. And, if we look outside of our own industry to the broader fields of environmental cognition and human emotional response, we may be able to make connections that can help us to establish a framework for a more holistic view of lighting's impacts In this article, we'll examine three threads of this framework -. one familiar to lighting practitioners and two that are probably less familiar - and explore how weaving these threads together can help to move us along to a deeper understanding of the broad range of human responses to the lighting stimulus.
1st thread: Lighting modes & subjective impressions (Lighting Psychology)
For most lighting practitioners, the phrase "Lighting psychology" immediately brings to mind the work of the late John Flynn. Flynn's research has been widely documented and discussed within the lighting community and is only briefly summarized here. (If you want a more comprehensive overview , I recommend both Architectural Lighting Design by Gary Steffy and Light:.. The Shape of Space by Lou Michel Both books provide excellent details on Flynn's findings and how they relate to architectural lighting design practice) Flynn and his colleagues explored what were at the time new research and analytical techniques, in an attempt to document and understand the full range of human impacts of lighting.
Flynn examined the human response to lighting by studying an array of subjective impressions related to architectural settings, in order to determine which of those impressions were affected by changes in the lighting stimulus. For some impressions, changes in the lighting produced significant changes in the response - impressions such as spaciousness, visual clarity, privacy, pleasantness, relaxation, complexity By linking lighting to these impressions, Flynn demonstrated that architectural lighting plays a much more significant role in the human experience than simply as an enabler of task performance..
In addition to studying human responses to lighting, Flynn also sought to understand the nature of the stimulus that produced those responses. Which attributes of lighting in a space seemed to relate to the various impressions that could result? Flynn identified four of these attributes, which he called the "lighting modes." The modes each express a continuum of changes in lighting between two extremes Flynn's lighting modes express the basic parameters of lighting which designers manipulate in creating the environments they desire -. bright / dim, uniform / non-uniform ., central / perimeter, and warm / cool Flynn's message was that as you change the lighting stimulus along these dimensions, you will produce changes in the human response in terms of the impressions that are reinforced And -. importantly - these responses will occur whether you planned for them or not.
The practicality of Flynn's work for lighting designers resided in his attempts to link the lighting modes to the human subjective responses. To reinforce a particular impression in a space, a designer could focus on certain aspects of the lighting mode descriptors in designing the lighting system. For example, the designer could reinforce a feeling of relaxation by employing non-uniform lighting on the perimeter room surfaces from warm-tone light sources. Uniform lighting on the perimeter room surfaces reinforces an impression of spaciousness. Although the design guidance that resulted from the Flynn work is qualitative in nature, many practitioners have found the linkages between the lighting modes and the subjective impressions to be a useful characterization of the stimulus and responses to lighting that move beyond task performance.
2nd thread: Making sense and being involved (Environmental Cognition)
Whereas Flynn's research focused specifically on lighting, other researchers with no particular interest in lighting examined the broad range of human responses to environmental stimuli. From the field of environmental cognition, the work of Kaplan and Kaplan provides important insights of relevance for lighting practice. These researchers sought to understand the factors that drive human preference for environments. One factor that emerged from their research is the desire to make sense of our surroundings. According to the Kaplans, when we are exposed to a new environment, finding a cognitive match for the environment in our memory is a primary goal, as a way of helping us to interpret and understand the new environment.
Often times we enter a new environment that has many similarities to other spaces we have experienced. The high degree of familiarity elicits a pleasant, comfortable reaction as we immediately are able to make sense of the setting. Other times we enter an unusual space that poses an entirely new experience, and we find it disconcerting as we struggle to make sense of the environment. The fundamental human need to make sense of our environment explains both of these disparate experiences, according to the Kaplans' research.
But what about the WOW factor in a new environment? We have all experienced a time when we encountered something completely new, but somehow the uniqueness and unfamiliarity were stimulating and exciting. And no doubt we share the common experience of entering a highly familiar space and finding that its very familiarity produces a low preference -. "! Oh please, not another drab hotel seminar room with boring uniform lighting" In this case, highly familiar leads to low preference Clearly, a second factor must interact with our desire to make sense of the environment in determining our preference.
The factor that supplements our drive to make sense of our environment, according to the Kaplans, is a desire for involvement with the environment. We want the environment to be interesting, we want it to invite us to explore and engage, we want a sense of complexity and mystery. This underlying purpose of involvement makes some novel environments seem exciting rather than just plain weird or overwhelming, and it also makes some very familiar environments seem just too uninteresting to us.
A summary of Kaplans preference chart. (Photo Courtesy of LiteControl)
Kaplan and Kaplan use two key words to capture the essence of these environmental aspects that drive our preference:. Coherence and complexity Coherence relates to our ability to make sense of the environment - does the environment provide us with cues that enable proper interpretation Are there? enough familiar elements in the environment that allow us to make mental matches to our prior experiences? If we are able to quickly make sense of an environment that is coherent, then the likelihood that we will develop a positive preference for the environment increases.
Although Kaplan and Kaplan were environmental psychologists who primarily focused on outdoor environments in their research, they recognized the connections between coherence and lighting effects Consider this quote.:
"It is also important that a change in texture or brightness in the visual array is associated with something important going on in the scene. In other words, something that draws one's attention within the scene should turn out to be an important object or boundary. .. If what draws one's attention and what is worth looking at turn out to be different properties, then the scene lacks coherence. "(Kaplan 1988, p. 49)
So a brightness emphasis that helps to make sense of an environment increases its coherence, making it a more pleasant space. Conversely, a change in brightness that is unrelated to anything important in the visual scene creates a lack of coherence, makes it more difficult to properly make sense of the space, and thereby reduces a person's preference for the space.
Coherence is critical, but a space that is completely coherent but overly simplistic fails to provide the stimulation and involvement that we desire. Complexity in the environment relates to our innate desire to engage, to be active participants with our environment. This cognitive link between complexity and preference also occurs in the realm of music appreciation In his excellent book, This is Your Brain on Music, Levitin writes.:
"When a musical piece is too simple we tend not to like it, finding it trivial When it is too complex, we tend not to like it, finding it unpredictable -. We don't perceive it to be grounded in anything familiar Music. , or any art form for that matter, has to strike the right balance between simplicity and complexity for us to like it. "
Apparently, our desire for a certain level of complexity holds true for a wide range of stimuli, whether a musical piece or an architectural environment. We desire coherent environments that we can easily interpret, while at the same time we desire an appropriate level of complexity to keep us interested.
The third thread: Pleasantness, arousal and control (Emotional Response)
From Flynn, led street light fixture Manufacturer see a thread of thought that describes the lighting stimulus in terms of some basic modes of variations and links those variations to the human response of subjective impressions of environments. From Kaplan and Kaplan, we weave in a thread that characterizes the stimulus along the parameters of coherence and complexity and relates those parameters to the response of human preference. And for our third thread, we look to the work of James Russell, whose career has been devoted to understanding human emotional development and response.
Kaplan and Kaplan stimulus along the parameters of coherence and complexity. (Photo Courtesy of LiteControl)
In Russell's model the primary emotional responses to the environment determine the behavioral responses. According to this model, human sensory systems process the environment and characterize the relationships between various aspects of the stimulus. This sensory input combines with personality characteristics to produce primary emotional responses in three areas - the pleasure that a person finds in the environment, the amount of arousal or stimulation that the environment provides, and the extent of dominance or control that people feel they have while in the environment.
The dominance response has some fascinating implications for lighting, as it depends on how much control we feel we have over the environment compared to how much we feel the environment controls us. The connections to automatic vs. Manual lighting controls are intriguing. We've seen studies that document greater energy savings when people have manual control, and we all know stories of negative reactions to fully automatic controls. We may be able to weave this thread together with the Kaplan's "desire for involvement" thread to derive a general principle about human reactions to environments. But, that exploration is beyond our scope for now.
Classification of Russell's theory on human reaction to environment. (Photo Courtesy of LiteControl)
Ultimately, Russell settled on the pleasure and arousal emotions as the two primary ways that we respond to environments. In Russell's view, whenever we enter a new environment, we quickly place it into one of four quadrants that are defined by the two axes of pleasure and arousal. This structure is shown in the figure below.
While Russell's initial work related directly to architectural environments, he later explored human emotional response to all types of stimuli. His model has been used in a variety of industries and applications, from advertising studies to experiments in childhood development. (In fact, his seminal paper in the Journal of Research in Personality titled, "Evidence for a three-factor theory of emotions," was recognized by the journal as one of the ten most frequently cited papers in its 43-year history.) So it seems that these emotional responses are fundamental to the human condition.
Russell argues that our emotional response to a stimulus along the two dimensions of pleasure and arousal is a single, integrated response rather than two distinct responses. The words we use to describe spaces reflect this sort of integrated response. An environment that we call, " stimulating, "is one that is both arousing and pleasant, while one that we call," tense, "is also arousing but a bit unpleasant. A" relaxing "space rates low on arousal but relatively high on pleasure, while a" dreary " space is also low on arousal but elicits a response that is low on pleasure as well.
Weaving the threads together for a unified design approach
So Flynn gives us a thread of a stimulus described by lighting modes, linked to the human response of subjective impressions of environments. Kaplan and Kaplan give us a thread of a preference response that appears to be linked to environmental stimuli that are both coherent and complex - we can make sense of them and they are interesting enough to elicit our involvement And Russell gives us a thread of primary emotional responses to stimuli that apparently drive our assessments of any environment, as we integrate a response along the dimensions of pleasantness and arousal. . How can we weave these disparate threads together?
We can explore this more fully in future articles. For now, consider a conference room application. The designer wants to provide uniform illuminance across the tabletop as the first layer of the lighting. Experimental evidence indicates that this central, uniform lighting increases the arousal level of the space, which seems to be preferred for a working environment. Next the designer adds some uniform perimeter lighting along two walls, to reinforce an impression of spaciousness. This layer articulates the architectural boundaries of the space, adding to its coherence. Accent lighting on some artwork on an end wall provides an additional layer of light. The non-uniformity of this layer increases the complexity of the visual scene, making it more interesting, inviting the occupant to engage with the environment. The space succeeds because the designer has structured the lighting solution so that it reinforces the desired architectural impressions (according to Flynn), it balances the human needs for coherence and complexity (according to Kaplan), and it provides levels of arousal and pleasantness (according to Russell) that are appropriate for the architectural context of the space.
We can think of many open questions that remain. Can we map the Flynn modes onto the Russell emotional responses? That is, what attributes of the lighting cause a space to seem more stimulating? Or less pleasant? Does increasing complexity as defined by Kaplan lead to higher levels of arousal? At what point does this increased complexity begin to compromise coherence, producing a less desirable emotional response? How do we match the cognitive and emotional needs to the context, so that we have differing guidelines depending on the desired human response to a work setting, a social setting, or a retail setting? These are all important and intriguing questions to explore as we seek to better understand the human brain on lighting.
More info you can visit:http://www.lead-lighting.com/products/sid108-1.htm
The human brain. (Photo Courtesy of LiteControl)
Stimulus -. Response It serves as the foundation of any basic Psychology class It defines our relationship to the world around us From Pavlov's dogs salivating at the sound of a bell to you quickly pulling your finger away from a hot pan, familiar examples of.. an involuntary response to a stimulus abound And it all seems pretty simple -. present this sort of stimulus, and you can count on a certain response.
Lighting practitioners work hard at getting the stimulus right to attain a desired response Historically, that has in large part meant a detailed and careful characterization of visual tasks under different lighting conditions -. The stimulus - and a variety of important methods for measuring visual performance as those conditions are varied - the response From Blackwell's Visibility Level to Rea's models of Relative Visual Performance, we have learned much about the nature of the stimulus-response relationships relating to human visual performance..
But what about those responses to lighting that go beyond considerations of task performance? Lighting can help create excitement in a themed environment. Lighting can help a person navigate through a new space. Lighting can help to bring about a sense of calm and peacefulness in a sacred setting. Lighting can help to add mystery in a theatrical production. And, lighting can cause us to strongly dislike a room which we would otherwise find appealing. How does our mind process the visual stimulus to produce these sorts of responses? What do we understand today about the way that we light buildings that enables us to link the stimulus of a lighted environment to the full array of cognitive and emotional human responses?
The answer, unfortunately, is - not much The depth and wealth of our research and knowledge in lighting's impacts on visual task performance only underscores the dearth of information on these other aspects of human responses to lighting..
But we do know a few things. And, if we look outside of our own industry to the broader fields of environmental cognition and human emotional response, we may be able to make connections that can help us to establish a framework for a more holistic view of lighting's impacts In this article, we'll examine three threads of this framework -. one familiar to lighting practitioners and two that are probably less familiar - and explore how weaving these threads together can help to move us along to a deeper understanding of the broad range of human responses to the lighting stimulus.
1st thread: Lighting modes & subjective impressions (Lighting Psychology)
For most lighting practitioners, the phrase "Lighting psychology" immediately brings to mind the work of the late John Flynn. Flynn's research has been widely documented and discussed within the lighting community and is only briefly summarized here. (If you want a more comprehensive overview , I recommend both Architectural Lighting Design by Gary Steffy and Light:.. The Shape of Space by Lou Michel Both books provide excellent details on Flynn's findings and how they relate to architectural lighting design practice) Flynn and his colleagues explored what were at the time new research and analytical techniques, in an attempt to document and understand the full range of human impacts of lighting.
Flynn examined the human response to lighting by studying an array of subjective impressions related to architectural settings, in order to determine which of those impressions were affected by changes in the lighting stimulus. For some impressions, changes in the lighting produced significant changes in the response - impressions such as spaciousness, visual clarity, privacy, pleasantness, relaxation, complexity By linking lighting to these impressions, Flynn demonstrated that architectural lighting plays a much more significant role in the human experience than simply as an enabler of task performance..
In addition to studying human responses to lighting, Flynn also sought to understand the nature of the stimulus that produced those responses. Which attributes of lighting in a space seemed to relate to the various impressions that could result? Flynn identified four of these attributes, which he called the "lighting modes." The modes each express a continuum of changes in lighting between two extremes Flynn's lighting modes express the basic parameters of lighting which designers manipulate in creating the environments they desire -. bright / dim, uniform / non-uniform ., central / perimeter, and warm / cool Flynn's message was that as you change the lighting stimulus along these dimensions, you will produce changes in the human response in terms of the impressions that are reinforced And -. importantly - these responses will occur whether you planned for them or not.
The practicality of Flynn's work for lighting designers resided in his attempts to link the lighting modes to the human subjective responses. To reinforce a particular impression in a space, a designer could focus on certain aspects of the lighting mode descriptors in designing the lighting system. For example, the designer could reinforce a feeling of relaxation by employing non-uniform lighting on the perimeter room surfaces from warm-tone light sources. Uniform lighting on the perimeter room surfaces reinforces an impression of spaciousness. Although the design guidance that resulted from the Flynn work is qualitative in nature, many practitioners have found the linkages between the lighting modes and the subjective impressions to be a useful characterization of the stimulus and responses to lighting that move beyond task performance.
2nd thread: Making sense and being involved (Environmental Cognition)
Whereas Flynn's research focused specifically on lighting, other researchers with no particular interest in lighting examined the broad range of human responses to environmental stimuli. From the field of environmental cognition, the work of Kaplan and Kaplan provides important insights of relevance for lighting practice. These researchers sought to understand the factors that drive human preference for environments. One factor that emerged from their research is the desire to make sense of our surroundings. According to the Kaplans, when we are exposed to a new environment, finding a cognitive match for the environment in our memory is a primary goal, as a way of helping us to interpret and understand the new environment.
Often times we enter a new environment that has many similarities to other spaces we have experienced. The high degree of familiarity elicits a pleasant, comfortable reaction as we immediately are able to make sense of the setting. Other times we enter an unusual space that poses an entirely new experience, and we find it disconcerting as we struggle to make sense of the environment. The fundamental human need to make sense of our environment explains both of these disparate experiences, according to the Kaplans' research.
But what about the WOW factor in a new environment? We have all experienced a time when we encountered something completely new, but somehow the uniqueness and unfamiliarity were stimulating and exciting. And no doubt we share the common experience of entering a highly familiar space and finding that its very familiarity produces a low preference -. "! Oh please, not another drab hotel seminar room with boring uniform lighting" In this case, highly familiar leads to low preference Clearly, a second factor must interact with our desire to make sense of the environment in determining our preference.
The factor that supplements our drive to make sense of our environment, according to the Kaplans, is a desire for involvement with the environment. We want the environment to be interesting, we want it to invite us to explore and engage, we want a sense of complexity and mystery. This underlying purpose of involvement makes some novel environments seem exciting rather than just plain weird or overwhelming, and it also makes some very familiar environments seem just too uninteresting to us.
A summary of Kaplans preference chart. (Photo Courtesy of LiteControl)
Kaplan and Kaplan use two key words to capture the essence of these environmental aspects that drive our preference:. Coherence and complexity Coherence relates to our ability to make sense of the environment - does the environment provide us with cues that enable proper interpretation Are there? enough familiar elements in the environment that allow us to make mental matches to our prior experiences? If we are able to quickly make sense of an environment that is coherent, then the likelihood that we will develop a positive preference for the environment increases.
Although Kaplan and Kaplan were environmental psychologists who primarily focused on outdoor environments in their research, they recognized the connections between coherence and lighting effects Consider this quote.:
"It is also important that a change in texture or brightness in the visual array is associated with something important going on in the scene. In other words, something that draws one's attention within the scene should turn out to be an important object or boundary. .. If what draws one's attention and what is worth looking at turn out to be different properties, then the scene lacks coherence. "(Kaplan 1988, p. 49)
So a brightness emphasis that helps to make sense of an environment increases its coherence, making it a more pleasant space. Conversely, a change in brightness that is unrelated to anything important in the visual scene creates a lack of coherence, makes it more difficult to properly make sense of the space, and thereby reduces a person's preference for the space.
Coherence is critical, but a space that is completely coherent but overly simplistic fails to provide the stimulation and involvement that we desire. Complexity in the environment relates to our innate desire to engage, to be active participants with our environment. This cognitive link between complexity and preference also occurs in the realm of music appreciation In his excellent book, This is Your Brain on Music, Levitin writes.:
"When a musical piece is too simple we tend not to like it, finding it trivial When it is too complex, we tend not to like it, finding it unpredictable -. We don't perceive it to be grounded in anything familiar Music. , or any art form for that matter, has to strike the right balance between simplicity and complexity for us to like it. "
Apparently, our desire for a certain level of complexity holds true for a wide range of stimuli, whether a musical piece or an architectural environment. We desire coherent environments that we can easily interpret, while at the same time we desire an appropriate level of complexity to keep us interested.
The third thread: Pleasantness, arousal and control (Emotional Response)
From Flynn, led street light fixture Manufacturer see a thread of thought that describes the lighting stimulus in terms of some basic modes of variations and links those variations to the human response of subjective impressions of environments. From Kaplan and Kaplan, we weave in a thread that characterizes the stimulus along the parameters of coherence and complexity and relates those parameters to the response of human preference. And for our third thread, we look to the work of James Russell, whose career has been devoted to understanding human emotional development and response.
Kaplan and Kaplan stimulus along the parameters of coherence and complexity. (Photo Courtesy of LiteControl)
In Russell's model the primary emotional responses to the environment determine the behavioral responses. According to this model, human sensory systems process the environment and characterize the relationships between various aspects of the stimulus. This sensory input combines with personality characteristics to produce primary emotional responses in three areas - the pleasure that a person finds in the environment, the amount of arousal or stimulation that the environment provides, and the extent of dominance or control that people feel they have while in the environment.
The dominance response has some fascinating implications for lighting, as it depends on how much control we feel we have over the environment compared to how much we feel the environment controls us. The connections to automatic vs. Manual lighting controls are intriguing. We've seen studies that document greater energy savings when people have manual control, and we all know stories of negative reactions to fully automatic controls. We may be able to weave this thread together with the Kaplan's "desire for involvement" thread to derive a general principle about human reactions to environments. But, that exploration is beyond our scope for now.
Classification of Russell's theory on human reaction to environment. (Photo Courtesy of LiteControl)
Ultimately, Russell settled on the pleasure and arousal emotions as the two primary ways that we respond to environments. In Russell's view, whenever we enter a new environment, we quickly place it into one of four quadrants that are defined by the two axes of pleasure and arousal. This structure is shown in the figure below.
While Russell's initial work related directly to architectural environments, he later explored human emotional response to all types of stimuli. His model has been used in a variety of industries and applications, from advertising studies to experiments in childhood development. (In fact, his seminal paper in the Journal of Research in Personality titled, "Evidence for a three-factor theory of emotions," was recognized by the journal as one of the ten most frequently cited papers in its 43-year history.) So it seems that these emotional responses are fundamental to the human condition.
Russell argues that our emotional response to a stimulus along the two dimensions of pleasure and arousal is a single, integrated response rather than two distinct responses. The words we use to describe spaces reflect this sort of integrated response. An environment that we call, " stimulating, "is one that is both arousing and pleasant, while one that we call," tense, "is also arousing but a bit unpleasant. A" relaxing "space rates low on arousal but relatively high on pleasure, while a" dreary " space is also low on arousal but elicits a response that is low on pleasure as well.
Weaving the threads together for a unified design approach
So Flynn gives us a thread of a stimulus described by lighting modes, linked to the human response of subjective impressions of environments. Kaplan and Kaplan give us a thread of a preference response that appears to be linked to environmental stimuli that are both coherent and complex - we can make sense of them and they are interesting enough to elicit our involvement And Russell gives us a thread of primary emotional responses to stimuli that apparently drive our assessments of any environment, as we integrate a response along the dimensions of pleasantness and arousal. . How can we weave these disparate threads together?
We can explore this more fully in future articles. For now, consider a conference room application. The designer wants to provide uniform illuminance across the tabletop as the first layer of the lighting. Experimental evidence indicates that this central, uniform lighting increases the arousal level of the space, which seems to be preferred for a working environment. Next the designer adds some uniform perimeter lighting along two walls, to reinforce an impression of spaciousness. This layer articulates the architectural boundaries of the space, adding to its coherence. Accent lighting on some artwork on an end wall provides an additional layer of light. The non-uniformity of this layer increases the complexity of the visual scene, making it more interesting, inviting the occupant to engage with the environment. The space succeeds because the designer has structured the lighting solution so that it reinforces the desired architectural impressions (according to Flynn), it balances the human needs for coherence and complexity (according to Kaplan), and it provides levels of arousal and pleasantness (according to Russell) that are appropriate for the architectural context of the space.
We can think of many open questions that remain. Can we map the Flynn modes onto the Russell emotional responses? That is, what attributes of the lighting cause a space to seem more stimulating? Or less pleasant? Does increasing complexity as defined by Kaplan lead to higher levels of arousal? At what point does this increased complexity begin to compromise coherence, producing a less desirable emotional response? How do we match the cognitive and emotional needs to the context, so that we have differing guidelines depending on the desired human response to a work setting, a social setting, or a retail setting? These are all important and intriguing questions to explore as we seek to better understand the human brain on lighting.
More info you can visit:http://www.lead-lighting.com/products/sid108-1.htm
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