Effect of Phosphor Particle Size on Luminous Efficacy of Phosphor-Converted White LED

Abstract

In this paper, the influence of YAG:Ce phosphor particle sizes on the lumen output and the conversion efficiency of both in-cup phosphor and top remote phosphor LED packages are investigated with 3-D ray-tracing simulations. The lumen output and the conversion efficiency of both types of phosphor-converted (pc) white LED packages are dependent on the size of YAG:Ce particles. The lumen output and conversion efficiency of both types of pc-white LED packages are minimal at the phosphor particle size with the size parameter of around one and are highest at the particle size in micron size. The simulation results show that both in-cup and top remote phosphor packages have the highest lumen output and the highest conversion efficiency at the particle size of around 20 mum.