Ideal luminous efficacy and color spatial uniformity of package-free LED based on a packaging phosphor-coated geometry.
This paper presents the optical simulation of the luminous efficacy of radiation (LER) and color spatial uniformity (CSU) of a package-free white LED conducted to boost the LER and simultaneously improve the CSU. According to the simulation results, the main effect on the LER and CSU was the change in the geometrical ratio of phosphor coating. Regardless of the packaging size, when the ratio of the top coating to the sidewall coverage of the phosphor layer thickness was in the range from 0.9 to 1.1, the maximum LER and optimal CSU can be simultaneously obtained. Besides, effectively increasing the volume of the overall packaging dimension to be 30 times the size of the chip can enable a package-free LED to achieve 90% saturated maximum LER without affecting the CSU.
Tsung-Xian
TX
Lee
Chien-Feng
CF
Chou