What are the causes of LED decay?

LED decay reason

1.LED light source material and the damage is caused by irreversible failure phenomenon of attenuation

LED decay refers to LED after a period of time after the light, the light intensity will be lower than the original light intensity, while the low part is LED light, at present our country has not yet developed LED decay standards, industry internal regulations 5000H small flux maintain rate greater than 70%, the U.S. Energy Star LM-80 regulations 6000H, luminous flux maintain that failure rate greater than 94.1%.

2 flux decline is not equal to the light

It is well known that the intensity of the LED will decrease with the increase of the junction temperature of the chip, and the optical efficiency will decrease. As long as the LED light source component does not exceed a temperature limit and stop LED damage, revived the intensity value will be restored when its temperature is LED, no matter how long, as long as it is not recognized as a constant initial intensity attenuation. The author believes that the LED decay refers to LED light source for some material damage and failure recovery phenomenon no longer,

That is, the ratio of the lossless light flux (initial light intensity) and the lossy optical flux (attenuation and non recoverable intensity) of the LED light source within the prescribed time period.

The main reason is the 3.LED light source light colloid temperature enough

As we all know, the chip (including fluorescent powder) is an inorganic material, the experiment shows that the chip and phosphor in two, three hundred degrees high temperature work principle is not a problem. From the light source system, main causes of LED decay is colloid temperature is not enough, the best packaging glue temperature only more than and 100 degrees, test proved that the integrated light source of a 50W colloid in the radiator is large enough working temperature is as high as more than and 200 degrees, either potting or PPA in a long period of time will be operating at high temperature caused by colloid cracking, carbonization, and chip separation and cause decay.

From the lighting system will lead to LED decay associated with the system including the cooling channel, thermal resistance, heat radiating material, cooling, and temperature related parts etc..

LED light source light is determined by the support structure, chip and phosphor powder quality, heat resistance, colloidal packaging factory and other conditions, these conditions are selected by the packaging factory, and is the first choice of weather resistant package support and colloid. In a sense, the core technology of LED packaging should be the development and manufacture of packaging support, which determines the use of LED light source, function and cost.