Analysis of the LED chip problems happened in the using process

Forward Voltage 1 drop dark light
A: Europe led outdoor lighting wholesale is the data for the ohmic electrodes and luminous touch , but touch the resistance, mainly by low concentrations of the information or the electrode substrate defects formed .

B: One is a non- ohmic electrodes and data touch , occurs mainly in the preparation process of the chip electrode transpiration squeeze when India first electrode layer or folder print , distribute orientation.

Other packages can be formed in the process of forward voltage drop , the primary reason there is insufficient curing silver paste , electrode holder or chip contamination resistance is large or the like touch the touch resistance unstable.

Forward voltage drop of the chip at a fixed voltage test , a small current through the chip , and then reflect dark spots , there is an appearance of dark light emitting chip itself is low power , forward voltage drop is normal.

2 hard bonding : ( primary has hit stick electrodes fall, penetrated electrode )

A: fight stick : the appearance of the primary oxidation or because the electrode gel

B: There is not strong and luminous touch data and thicker wire layer is not strong , with thick layers during fall based.

C: punch electrodes : usually with information on the chip , the information is not brittle and high intensity data easily penetrated electrodes , usually GAALAS information ( such as high red , infrared chip ) than the GAP data easily penetrated electrode ,

D: Commissioning should soldering temperature bonding , ultrasonic power, ultrasonic time , pressure, silky size, stent positioning adjustment.

3 luminous color differences:

A: luminous color chips with a significant difference between the first and foremost because the wafer data queries , ALGAINP four elements of quantum information selected layout is very thin, it is difficult to ensure the growth of the regional components together . ( Bandgap component resolutions , resolutions bandgap wavelength ) .

B: GAP yellow-green chip , the emission wavelength is not a great error , but because the human eye is sensitive to this band of color , very simple to detect yellowish , greenish. Because the wavelength of the wafer data resolution , the smaller the area , showing the concept of the color error is smaller, so there is method in the vicinity of the selected M / T job.

C: GAP some chips emitting red orange color is biased because its light emission mechanism is a direct leap . Affected by the impurity concentration , current density increased, prone to luminous full offset and impurity levels , light is beginning to orange yellow.

4 brake fluid effects:

A: light-emitting diodes can not be turned on in the normal voltage , when the voltage heightening to a certain extent , the current occurrence of sudden change .

B: brake fluid representation of the reason is the occurrence of luminous information presented during epitaxial films grown reverse sandwich , have this representation at IF = 20MA LED forward voltage drop when the test has to hide sex , in the use of the process is not for the polar voltage large, reflected not lit , the available information on the test instrument from the test transistor curve tracers , and can pass a small current iF = forward voltage drop under 10UA to discover , forward voltage drop significantly smaller current is too large, then the questions can be formed .

5 Reverse Leakage :

A: Reason: under epitaxial materials, chip manufacturing, packaging equipment , tests typically 5V reverse leakage current of 10UA, reverse quiz can also be fixed reverse voltage current.

B: not the same type of Europe led outdoor lighting wholesale features a large difference : P Green , Pu Huang chip reverse breakdown can reach more than a hundred volts, while the S & P chips are between ten to twenty volts.

C: Reverse leakage current formed by the first epitaxial PN junction formed by the internal layout of the drawbacks , the side surface of the chip manufacturing process or not with silver corrosion buildup in plastic wire measuring surface , with an organic solution of silver glue distribution is prohibited . In order to avoid the appearance of silver plastic climbed through the capillary junction.

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