Arithmetic and experimental approach to effect of visible light absorption on silicone plate in high-power LED module. (April 2018) - Jung, Jung Hwa
Highlights: To predict the heat by visible light absorption from blue chip and yellow phosphor. Optical energy modeling is developed for silicone and phosphor mixed silicone layers. Effect of the visible light absorption on LED packages is no longer negligible. Abstract: In a light emitting diodes (LEDs), the effect of visible light absorption on silicone encapsulant temperature has largely been overlooked by the scientific community. In this paper, we develop a new optical energy model to calculate the absorption power of a silicone plate in a remote phosphor LED module. In addition, we introduce a unique experiment for visible light absorption. Three types of silicone plate are investigated – a transparent silicone plate in a blue LED and two phosphor-mixed silicone plates (YAG:Ge, yellow phosphor) in white LEDs. We discover that by mixing phosphor with transparent silicone, the absorption coefficient is increased to 2.5 times in the case of 3 wt% phosphor-mixed silicone, and 5.9 times in the case of 30 wt% phosphor-mixed silicone compare with transparent silicone plate. Moreover, we find that visible light absorption only is able to increase silicone plate temperature by 7.3 °C in the case of transparent silicone, 18.7 °C in the case of 3 wt% phosphor-mixed silicone, and 43.3 °C in the case of 30 wt% phosphor-mixed silicone.