Self-adaptive phosphor coating technology for white LED packaging

Phosphor-converted light-emitting diodes(pcLEDs), which employ blue LEDs with yellow phosphors to generate white light illumination, is a widely used solidstate lighting source. In order to conduct a phosphor layer coating with high quality on LED chip, a self-adaptive coating technology is introduced in this paper. A slurry coating technique combined with self-exposure method is applied and developed to demonstrate the benefits of selfadaptive coating layer. For self-exposure, the slurry coating is exposed to the blue emission of LED itself other than to ultraviolet(UV) light outside to make photoresist crosslinking. Results of measurement indicate that white LEDs with self-adaptive coating have shown self-adaptability to the angular distribution of intensity of blue light and performed higher spatial color uniformity than those with conventional coating and other conformal coating.