While LED is currently facing a major problem is the problem of life, due to the price of white LED is still very high, in order to in the lighting market foothold, allows users to both save energy and money, must rely on long life and save the electricity to make up for the lamps and lanterns of high prices. Now, the life of the white LED makes it hard to do that.From the normal use of LED point of view, the most important factor affecting the life of LED is hot. Sources of heat, have normal material resistance in the electricity produced by Joule heat, PN junction produces heat, produce and process in the parasitic resistance of Joule heat and light is attracted to produce heat. The accumulation of heat makes the temperature rise, the temperature rise makes the performance of the chip decline, aging, degeneration.
1, What is the LED decay
LED light decay is light in the transmission signal attenuation, and at this stage of the global LED manufacturers to make products LED light decay to varying degrees, high power led also exist decay, and temperature have direct relationship is mainly determined by the chip, phosphor and packaging technology. At present, the white LED on the market is likely to decline the issue of primary civil lighting into the.
2, Two major factors influencing the LED decay
1) LED quality problems
The LED chip is not used, the brightness attenuation is fast.
The production process has the defects, the LED chip heat dissipation can not be well from the PIN foot, resulting in LED chip temperature is too high to make the chip attenuation.
2) use of the conditions of the problem
LED for the constant current drive, there is a part of the LED using voltage driven reasons for LED attenuation.
Drive current is greater than the rated drive condition. In fact, cause the light decay of LED products for many reasons, the most critical problem is the heat, although many manufacturers in secondary products should not be particularly pay attention to cooling problems, but long-term use of these secondary LED products, attenuation degree will than focus on heat dissipation of LED products. The radiating effect of the LED chip itself thermal resistance, silver glue, substrate, and colloidal gold and also and decay.