Influence of dome phosphor particle concentration on mid-power LED thermal resistance

The modern white mid-power LEDs usually contain phosphor particles encapsulated in silicone dome material. The particles convert the blue light emitted from the epitaxial layer and play significant role in thermal processes of LED packages. In this paper the influence of the phosphor particles concentration and effect of sedimentation on thermal resistance and junction temperature of mid-power LEDs are investigated. Thermal transient measurements, thermal imaging and finite element simulations are used. It is shown that the sedimentation of phosphor particles has an impact on both thermal resistance and junction temperature of mid-power LEDs. General trends for phosphor particles concentration effect on thermal properties of a mid-power LED are determined.