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What is LED light attenuation

Dec 13, 2019

What is LED light attenuation?


LED light attenuation refers to the light intensity of the LED will be lower than the original light intensity after lighting, and the lower part is the light attenuation of the LED. Generally, the LED package manufacturers do the test under laboratory conditions (at a normal temperature of 25 ° C), and continuously illuminate the LED with a DC power of 20MA for 1000 hours to compare the light intensity before and after the light is turned on.


Calculation method of light attenuation

N-hour light attenuation = 1- (N-hour light flux / 0-hour light flux)


The light attenuation of LEDs produced by various companies is different, and high-power LEDs will also have light attenuation, and it has a direct relationship with temperature, which mainly depends on the chip, phosphor and packaging technology. The luminous attenuation of LEDs (including luminous flux attenuation, color changes, etc.) is a measure of LED quality, and is also a matter of great concern to many LED manufacturers and LED users.


According to the definition of the life of LED products in the LED industry, the life of an LED is the cumulative operating time from the initial value to the disappearance of light to 50% of the original value. It means that when the LED reaches its useful life, the LED will still be on. However, under lighting, if the light output is attenuated by 50%, no light is allowed. Generally, the light attenuation of indoor lighting cannot be greater than 20%, and the light attenuation of outdoor lighting cannot be greater than 30%.