Controlling Phosphor Particle Distribution for High-Angular-Color-Uniformity and Low-Cost LEDs Based on Thermalcapillary Flow

Low cost and high performance are the pursuing goals of the light-emitting diode (LED) packaging. The phosphor layer configuration of LEDs significantly influences optical performances. In this study, thermalcapillary flow was introduced in the phosphor coating by the blue laser local irradiation. It has been demonstrated to successfully manipulate the phosphor particle distributions. In the phosphor dispensing coating, a centripetally concentrated particle distribution was realized and resulted in high angular color uniformity (ACU) and low-cost manufacture. Its angular correlated color temperature (CCT) deviation was reduced by more than 65%, compared to the traditional phosphor dispensing coating. Besides, the phosphor amount is saved by about 12%. The mechanism of ACU enhancement is analyzed. The realized phosphor particle distribution can inspire further development of the optimized phosphor layer configuration.