Optimized Self-Adaptive Phosphor-Coating Structure of pc-WLEDs by Double Conformal Coating Technology

Abstract

Since the advent of phosphor-converted white light-emitting diodes (pc-WLEDs), its coating structure has attracted the attention of many researchers because the phosphor coating structure is one of the most important factors affecting the quality of pc-WLED lighting. In this experiment, we used a double conformal coating to optimize the phosphor coating structure. This optimized phosphor coating structure consists of two self-adaptive coating structures: one plays a role as a remote layer and another as a phosphor layer. The results of this experiment showed that the new coating structure improved the uniformity of yellow–blue photon ratio (Y/B) and angle-dependent correlated color temperature (CCT) compared to the single self-adaptive phosphor coating structure. In addition, after aging testing, the CCT uniformity of double conformal coating was still superior to that of single self-adaptive phosphor coating.