Optimization of output and phosphor consumption for phosphor-converted white light-emitting diodes

Using ray-tracing simulation based on Monte Carlo method, the effects of phosphor concentration and thickness on light output and phosphor consumption of pc-wLEDs were investigated in this work. The simulation was improved to comprehensively imitate the whole optical process of pc-wLEDs, including total produce of chip and phosphor light, losses in the propagation, and output. Experiments were conducted to verify the simulation. Results show that, light output changes non-monotonously over phosphor concentration and thickness, having maximum value. Experimental maximum light efficiency of 158 lm·W−1 was obtained at concentration of 16 wt%, 6 % higher than that of 11 wt% and 17 % higher than that of 33 wt%. Phosphor consumption of pc-wLEDs increases linearly with the increase of phosphor concentration and the decrease of thickness. Experimental phosphor consumption of pc-wLEDs with concentration of 11 wt% is only 37 % of that of 33 wt%.