Angular color uniformity improvement for phosphor-converted white light-emitting diodes by optimizing remote coating phosphor geometry

Angular color uniformity (ACU) of a king of popular remote phosphor coating LED packaging with spherical phosphor shape with uniform thickness was invested by the Monte Carlo ray tracing method. The simulation results indicate the yellowish ring can't be avoided under uniform phosphor thickness in angular range of 0°-180°. The optimized phosphor geometry was proposed whose thickness gradually reduces from the center to the edge. The optimized phosphor geometry can improve ACU 45%, compared with the initial uniform thickness phosphor layer.