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What is the light decay value of LED?
source:未知 date: 2019-05-25 09:18 hits:
There must be some discrepancy between the data detected by a single UV LED light source on the aging board and the data detected when the UV LED light source is assembled into a LED panel lamp. The difference depends on the electrical parameters of the UVLED panel lamp and the design of the lamp, as well as the environment in which the lamp is used.
First, choose what kind of UV LED lamp.
This is very important, the quality of LED light source can be said to be an important factor. For example, the same 14 mil optical chip as the representative, with ordinary epoxy resin as the base glue and white glue and packaging glue packaging LED, a single light at 30 degrees, a thousand hours later, the attenuation data is 70%; if encapsulated with class D low-decay glue, in the same aging environment, the light decay per thousand hours is 45%; if encapsulated with class C low-decay glue, in the same environment. In the same aging environment, the 1000-hour light decay is 12%; in the same aging environment, the 1000-hour light decay is - 3%; in the same aging environment, in the same aging environment, the 1000-hour light decay is - 6%.
Why do different packaging processes lead to big differences?
One of the main reasons is that UVLED chips are afraid of heat. Occasionally more than 100 degrees of heat in a short period of time, that is not important, for fear of being in high temperature for a long time, is a great damage to the UV LED chip.
Generally speaking, the thermal conductivity of ordinary epoxy resin is very small. Therefore, when the UVLED chip lights up, the UVLED chip emits heat, while the thermal conductivity of ordinary epoxy resin is limited. Therefore, when you measure the temperature of the UVLED bracket from the outside of the UVLED white lamp to 45 degrees, the central temperature of the chip in the UVLED may exceed 80 degrees. The temperature node of the UVLED is actually 80 degrees, so when the UVLED chip works in the temperature-saving temperature, it is very suffering, which accelerates the aging of the UVLED.
When the UVLED chip is working, the central temperature produces a high temperature of 100 degrees. It can immediately export heat through 98% of the support pin, thus reducing the damage of heat to it. Therefore, when the temperature of the UV LED bracket is 60 degrees, its chip center temperature may be only 61 degrees.
From the above data, it can be seen that the choice of packaging process of UVLED directly determines the optical decay of UVLED devices.
Secondly, the working environment temperature of LED beads.
According to the aging data of single LED, if only one LED lights up and the ambient temperature is 30 degrees, then the bracket temperature of a single LED will not exceed 45 degrees. At this time, the life of this LED will be ideal.
If 100 LEDs are lit at the same time and the spacing between them is only 11.4 mm, then the support temperature of the LED around the stack may not exceed 45 degrees, but the LED in the middle of the stack may reach 65 degrees. At this time, the LED beads are a test. Then, the LED in the middle will theoretically fade faster, while the LED around the lamp stack will fade slower.
But if the LED beads are more than 25 mm apart, then the heat they diverge from each other will not accumulate so much. At this time, the temperature of each LED bracket should be less than 50 degrees, which is more conducive to the normal operation of the LED.
If the working environment of the UV LED is relatively cold, the average temperature of the whole year may be only about 15 degrees, or smaller, then the life of the UV LED will be longer.
Or, when the LED works, there is a small fan blowing beside it to help it dissipate heat, which is very helpful to the life of the LED.
Anyway, you should know that LED is afraid of heat. The higher the temperature, the shorter the life of LED, the lower the temperature, the longer the life of LED. The ideal working temperature of the LED is, of course, between minus 5 and zero. But it's basically impossible.
Therefore, after we understand the ideal working parameters of LED beads, we will try our best to strengthen the function of heat conduction and heat dissipation in the design of lamps and lanterns. Anyway, the lower the temperature, the longer the life of LED.