Color Uniformity Enhancement for WLEDs Using Inverted Dispensing Method

The inverted dispensing (ID) method is proposed to fabricate remote phosphor layers (RPLs) with cone-like shapes for white light-emitting diodes (WLEDs) to improve their color uniformity. We introduce surface evolver packages and optical simulations to study the effect of the surface tension on the optical performance of these WLEDs during the ID process. The results show that a decreasing surface tension contributes to a sharpened geometry of the RPL. This sharpened surface geometry is responsible for the optimization of the color uniformity by deflecting blue light towards central angles. The proposed ID method is simple and efficient. The color uniformity performance can be tuned by selecting silicone with a proper surface tension without affecting the total correlated color temperature and sacrificing the WLED's optical power.