led phosphor self-heating mechanism

Led phosphor work produces heat, and the led phosphor work is easier to heat than led p-n junction. reason is conversion efficiency of led phosphor do not meet these criteria 100%，As phosphor is sucked from the blue light change into the yellow light, part of light energy is converted into heat energy, led phosphor is mixed with silica gel,hermal conductivity of silica gel were very low. just only have 0.16 W/mK，in that case, the heat will be accumulated in a small area. and the heat could suddenly become much hotter. the greater is the led light density, the  led phosphor of heat release was increased.