A POF based breakdown method for LED lighting color shift reliability

Abstract

Color shift mechanism of LED lighting is complex due to its much more comprehensive structure, generally composed of LED die, phosphor, silicone, reflector, diffusers, and so on, each of them may contribute to the color shift during operation. This paper proposed a breakdown method for the color shift study and investigation on the LED based luminaire level products. For the downlight investigated in this paper, the LED packages part has the most important contribution in color shift, higher than 1sdcm even under the normal operation conditions of room temperature. Both humidity and temperature conditions can be used to accelerate the color shift of the mid power 5630 package and the humidity has a stronger acceleration. The reflective part contributes far less than 1 sdcm even when the reflective material crumbles after 4000hours of humidity test under certain conditions.