The encyclopedia Led application and classification

According to shape classification, wafer and chip is generally divided into square pieces. Where the wafer is relatively low-speed performance is not stable enough, I generally do not use led street lighting fixture; size square piece generally measured, such as 12mil (1mil = 0.0254 mm2). In general, the same brand of chips, chip size, the higher the brightness. LED lamp beads I most often used, usually in red and yellow 9 ~ 12mil, white, blue, green, generally in the 12 ~ 14mil, which is the most common chip market, if a larger chip, brightness Although it is possible to improve a lot, but a substantial increase in chip prices, which is the reason why the large chip size rarely used.
LED color tips:

Is determined by its different color LED chips of different wavelengths determined, for example, red light chip wavelength is generally 620 ~ 630nm (nanometers), green chip is generally wavelength 527nm, the wavelength of the blue chip generally is 470nm, yellow chips generally wavelength is 585nm, white LED is blue chip, but in the blue chip with the right amount of phosphor to emit a white light.

LED classification:

Size divided by power: can be divided into low-power, high-power (0.5W over the industry in general to be called high power lamp lights)

Divided by shape: can be divided into DIP and SMD.

Straw hat LED: they can be subdivided into the cap size F3 (cap diameter of 3mm), F5 (cap diameter of 5mm); or by the shape of the lamp is broken boundless, thin edge, thick edge, round; press transparent or not transparent cap can be divided into mist.

Piranha LED: lamp of the same size can be divided into F3, F5, according to the shape of the lamp into the round (ie, the most common piranha lights), flat head (this is very special shaped head, the luminous angle close to 180 degrees, generally used in situations require astigmatism).

Low-power SMD LED: Dimensions can be divided according to 0805,1206,3020,3528,5050 or 5060 (5050 and 5060 the difference is very small, the naked eye is difficult to distinguish, for unprofessional customers can call with his habit).

High-power LED: Press the power to distinguish between general, a common 0.5W, 1W, 3W, 5W, 8W ......

LED chips (chip) Number of common sense:

With an LED lamp, the most common is the use of only one chip, but in special cases can use two was even up to four chips, such as: a hat light may be one to two chips (in view of its relatively small size, heat dissipation is not easily lead to unstable performance, generally using only one or two chips); a piranha lights can be used one, two, three, four chips, I was the most commonly used one and two chips; you can use a light patch 3528 , two, three chips (our usual one, two chips), SMD 5050/5060 generally use three chips. Special note: When the three chip SMD lamps, there are two cases:

1. Three identical color chips

2. Three chips are red, green and blue, that is, we often say that the RGB lights

LED light-emitting angle (viewing angle) of common sense:

The most common line LED emitting angle is 120 degrees, 45 degrees can do special, or 15 degrees.

LED voltage (voltage) of common sense:

A single low-power LED lamps, different colors, which require different voltages. Red / Yellow: generally 1.8 to 2.1 volts, white / green / blue: generally 3.0 to 3.6 volts. 1W high power lamp voltage requirements the same as above. www.6366msc.com

LED current (current) common sense:

1. Low-power led street lighting Manufacturer (including plug-in or SMD), allowing the current through each chip is generally no higher than 20 mA; allow current through each of the two-chip lamp generally no higher than 40 mA; with rationale for each three-chip light not higher than 60 mA.

2. High power LED, I often used is 1W, which allows a maximum current of 150 mA through.

LED brightness (intensity) of common sense:

1. Candlelight, international candle, candela (candela) of the definition

At 101,325 Newton per square meter standard atmospheric pressure, an area equal to 1/60 cm absolute "black body" (i.e., able to absorb all of the external light reflected from an object and there is no ideal), pure platinum (Pt) solidification temperature (about 2042K eligible 1769 ℃), the luminous intensity in the vertical direction is 1 candela. And, candlelight, international candle, candela three concepts are different, not the same. In terms of quantity, equal to 60 candela 58.8 international candles, lights a candle hefner international candle equals 0.885 or 0.919 candela.

2. luminous intensity and brightness

Referred to as light emission intensity is strong, international unit is candela (cd) abbreviated cd. Lcd refers to luminous flux emitted from the light source in the specified direction unit solid angle. The radiation source is uniform, the light intensity I = F / Ω, Ω is the solid angle, in units of steradian (sr), F is the luminous flux, in units of lumens, for a point light source by I = F / 4. Brightness is the brightness of the light-emitting surface, is the ratio of the light emitting surface of the luminescent intensity in the specified direction and the direction perpendicular to the light emitting surface of the specified area of the unit is candela / square meter. For a diffuse scattering surface, despite the different intensity and luminous flux in all directions, but the brightness is equal in all directions. The TV screen is similar to such a diffuse scattering surface, so images are viewed from all directions, have the same sense of brightness.