LED lumen attenuation is the weakening of the light signal during transmission. LED products made by global leading manufacturers at the present stage have lumen attenuation in different grades after used for a period of time and this phenomenon also exists in high power LEDs. Then, what causes LED attenuation? Lumen attenuation is directly related to the temperature, and is mainly determined by the chip, phosphor used and the packaging technology. At present, lumen attenuation has become the chief problem for white LED to march into civil lighting field.