Self-Adaptive Structure of Remote Phosphor for Phosphor-Converted White LEDs

High-efficiency white light-emitting diodes (LEDS) with superior spatial color homogeneity (SCH) have been investigated. In this paper, a new method of packaging of phosphor-converted white LEDs (pc-WLEDs) that employs a self-exposure technique as well as a remote phosphor configuration is presented. It is suggested that this remote phosphor configuration reduces the backscattering of emission light of LEDs as well as the operating temperature of the phosphor, which improve the luminous efficiency and reliability of pc-WLEDs. The slurry method with self-exposure process was applied to achieve a self-adaptive remote phosphor coating layer surrounding the LED chips which could map the angular intensity distribution of blue light emitted from LED chips every direction and therefore improve the spatial color homogeneity. The experimental results show that pc-WLEDs with self-adaptive remote phosphor coating has remarkable advantages over conventional dispensing coating and conformal coating in terms of efficiency and color homogeneity.