A Method to Eliminate the Effect of Phosphor Sedimentation on LED’s Angular Color Uniformity

Phosphor sedimentation has a great impact on the LED’s correlated color temperature (CCT) and the angular color uniformity (ACU). But fewer solutions have been proposed to overcome this effect. In this paper, we analysed the fundamental mechanism behind the phosphor sedimentation effect on LED’s ACU and proposed a simple structure to eliminate the effect. Monte Carlo ray-tracing simulations were conducted to validate the idea. The results show that the maximum CCT deviation with the proposed structure is within 100 K while that of the conventional one is as high as 680 K, and the ACU increases from 0.8811 to 0.9809 by 11.33%. It is concluded that this proposed structure has potential to be used to eliminate the phosphor sedimentation effect.