Enhancement Spatial Color Uniformity of White Light LED Lamps by Adding Silicon Dioxides in Phosphor Layer

Recently, high-power light-emitting diodes (LEDs) have attracted great attention on the study and made remarkable progress. In this paper, method for enhancing uniform white light of a multi-chip white light LED by adding silicon dioxides in the phosphor layer is presented. Firstly, theory of study by using Mie theory and Monte Carlo ray-tracing is proposed. And then simulation and experimental results by using package LightTools software are performed. The experimental results and theory have the same direction: 1) the angular color temperature in narrow angles is much higher than that in wider angles for the non-SiO2 case and 2) in significantly reducing CCT deviation of a multi-chip white light LED by adding silicon dioxides in the phosphor layer.