Arithmetic and experimental approach to effect of visible light absorption on silicone plate in high-power LED module

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.