Understanding heat dissipation of a remote phosphor layer in an LED system

This study investigated how passive and active cooling methods dissipated the heat from a remote phosphor layer in an LED system. The focus was on quantifying the amount of cooling contributed by each heat dissipation mechanism, namely, conduction, convection, and radiation. The conductive heatsink surrounding the phosphor layer acted as an extended surface for dissipating the heat. In this study, the effect of increasing the heat extraction area between the phosphor layer volume, changes in convection coefficients, and changes in surface emissivity of the heatsink on phosphor layer temperature were investigated. The surface temperature of the remote phosphor layer was measured using an infrared imaging camera. At the first stage the metal heatsink removed the heat from the phosphor layer by conduction, then the heat from the metal heatsink was dissipated to the ambient via convection and radiation. The results indicated a significant reduction in phosphor layer temperature. Additionally, active cooling further reduced the phosphor layer temperature. The results also showed that the temperature distribution on the phosphor layer improved with the metal heatsink configuration.