Why LED lamps are getting darker
The LED light source module is generally composed of a substrate, a chip, a packaging material, a lens, etc. In daily use, the long-time operation of the LED easily causes the LED to become darker and darker, and even the light fails. For this problem, D.L. Barton has done research experiments.
There are some reasons for the failure of the LED light source module. Generally, the following are the main points:
LED lamps are getting darker reasons:
1.The packaging material is degraded;
Under long-term work, the LED will cause the temperature of the LED to rise, resulting in a large decrease in the optical transparency of many polymers in the LED exterior packaging material (such as epoxy resin), resulting in a decrease in the light-emitting efficiency of the LED;
The study found that when the LED temperature reaches 95 degrees and the current is greater than 40 mA, the LED package material will be carbonized;
2.During the LED package soldering process, the electrode is contaminated by droplets, oil stains and dust, which may lead to poor solder joint welding;
Solution: Test the relevant position to ensure that the product quality is ok. At present, the most widely used Non-Destructive X-RAY equipment in the market, its powerful penetrating power can detect LED bubbles, welding bubbles and other defects;
3.The selection of solid crystal glue, it needs to be noted that some raw materials have high brightness, but poor thermal conductivity, especially high temperature, it is easy to cause the material to peel off the wafer, causing short circuit;
For LED defects, the biggest problem is package soldering, We suggest companies should pay more attention before and after packaging to ensure that the LED package is OK, no bubbles or soldering defects.
The above is LED lamps are getting darker reasons.
Family of Industrial X-ray inspection machine & BGA rework station
Last Article: SMT BGA solder ball inspection method
Next Article: Formation and prevention of SMT BGA voids
Maybe you still are interested in: Solder paste printing defects and solutions in SMT chip processing process