Near-/Mid-Field Effect of Color Mixing for Single Phosphor-Converted Light-Emitting Diode Package

In this letter, it is found through both experiments and Monte Carlo ray-tracing simulations that the working distances would influence the correlated color temperature (CCT) and the angular color uniformity (ACU) of single phosphor-converted light-emitting diode (pc-LED) package. When the working distance decreases, the CCT decreases and the ACU deteriorates. The deterioration caused by short distance is regarded as the near-/mid-field effect of color mixing of pc-LED. This discovery of the near-/mid-field effect may help to find some specific packaging methods to control color mixing and improve white light quality for some applications where the working distance was short.