Why do LED lights dim after a period of time

- Jun 21, 2019-

1. First of all, if the power supply is battery, please check whether the battery is still running

2. If it is an external power supply, considering the light decline, it is mainly determined by the LED chip.

LED light decay refers to that after LED is lit for a period of time, its light intensity will be lower than the original light intensity, and the lower part is LED light decay. Generally, LED packaging manufacturers do tests under laboratory conditions (at room temperature of 25℃), and use 20MA dc to continuously light LED1000 hours to compare the light intensity before and after lighting.

The cause of light decay

I. quality problems of LED products:

1. The LED chip adopted has poor constitution and fast brightness decay.

2. There are defects in the production process. LED chip heat dissipation cannot be properly derived from PIN PIN, leading to excessive LED chip temperature and aggravated chip attenuation.

Ii. Conditions of use

1. LED is constant current drive, and some LED USES voltage drive to attenuate LED.

2. The driving current is greater than the rated driving condition.

In fact, there are many reasons leading to LED product light decay, the most critical is the heat problem. Although many manufacturers do not pay special attention to the heat dissipation of secondary products, the degree of light decay of these secondary LED products will be higher than that of LED products that pay attention to heat dissipation. The thermal resistance of the LED chip itself, the influence of the silver glue, the heat dissipation effect of the substrate, as well as the colloid and gold wire are all related to the light decay.