Angular CCT Uniformity of Phosphor Converted White LEDs: Effects of Phosphor Materials and Packaging Structures

In this work, we studied the effect of different packaging parameters on the angular homogeneity of correlated color temperature (CCT) in phosphor-in-cup light-emitting diode (LED) packages, including phosphor particle concentration, phosphor-layer surface curvature, and lens surface curvature, using a Monte Carlo ray tracing simulation tool. An optimized packaging geometry with convex phosphor layer was achieved with good CCT uniformity and highest lumen efficiency. Moreover, an approach was developed for the prediction of color uniformity and lumen efficiency when varying the surface curvature of either phosphor layer or clear lens, since the inconsistency of phosphor layer or lens cap happened commonly to the fabricated phosphor conversion white LEDs (pc-WLEDs).