Phosphor particle spatial patterning for high angular color uniformity LED packaging through selective curing and settling

Abstract

Uniform angular color distribution is regarded as a key index of high-quality light-emitting diode(LED) devices. The angular color uniformity is decided by the coated phosphor layer in the LED packaging. In this study, we demonstrated a method of manipulating phosphor particle spatial distributions for the high ACU LED packaging. In the presented method, the laser irradiation was used to selectively and rapidly cure the phosphor gel. The particles in the uncured phosphor gel settled on its bottom with the action of the gravity. By this method, we realized a phosphor layer configuration in which a conformal particle layer was deposited on the LED chip surfaces and the particles were randomly and uniformly distributed into the gel located above the LED chip. Compared to the dispensing phosphor coating and simple settling coating, such a phosphor particle spatial distribution significantly enhance the ACU, and the enhancement reaches more than 51%.