Definition and influence factors of LED light decay

Update:27 Sep 2020
Summary:

1. What is LED light decay? The light decay of LED prod […]

1. What is LED light decay? The light decay of LED products is the weakening of the signal during transmission. At this stage, the LED products made by major LED manufacturers all over the world have different degrees of luminous decay. High-power LEDs also have luminous decay. Temperature has a direct relationship, mainly determined by the chip, phosphor and packaging technology. At present, the light decay of white LEDs on the market may be one of the most important issues in the march to civil lighting.

  2. Two major factors affecting LED light decay

  1) LED quality problem • The LED chip used is not of good quality and the brightness decays quickly. • There are defects in the production process, and the heat dissipation of the LED chip cannot be well derived from the PIN pin, which causes the high temperature of the LED chip to increase the chip attenuation.

2) Use condition issues • The LED is driven by constant current, and some LEDs are driven by voltage to cause the LED to attenuate. • The drive current is greater than the rated drive conditions. In fact, there are many reasons for the light decay of LED products, and the most critical one is the heat problem. Although many manufacturers do not pay special attention to the problem of heat dissipation in their secondary products, under long-term use of these secondary LED products, the degree of light decay will be higher than that of heat dissipation. The LED products are higher. The thermal resistance of the LED chip itself, the influence of silver glue, the heat dissipation effect of the substrate, and the glue and gold wire are also related to light decay.

One of the main problems faced by white light LEDs is the longevity problem. Since the price of white light LEDs is still very high, if you want to gain a foothold in the lighting market and allow users to save both electricity and money, they must be compensated for by the electricity costs saved by the long life. The high price of lamps. Now, the lifespan of white LEDs makes it difficult to do this.

  From the perspective of normal use of LEDs, the most important factor affecting the life of LEDs is heat. The sources of heat include Joule heat generated by the normal resistance of the material when energized, heat generated by PN junction, Joule heat generated by parasitic resistance caused by the process, and heat generated after light is attracted. The accumulation of heat causes the temperature to rise, and the rise in temperature causes the performance of the chip to decline, degrade, age, and denature.

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