A Detailed Study on Phosphor-Converted Light-Emitting Diodes With Multi-Phosphor Configuration Using the Finite-Difference Time-Domain and Ray-Tracing Methods

Although the optical simulations have been widely adopted to study phosphor-converted light-emitting diodes (pcLEDs), to the best of our knowledge, there is no study that investigates the pcLED model considering the effect of phosphor particles with irregular shapes. In order to explore this topic, we employ the finite-difference time-domain method to characterize the phosphor-converted element (PCE) model. Furthermore, the PCE-based pcLED with YAG:Ce and nitride phosphors is investigated by the ray-tracing method. The results show that the rod-shaped nitride phosphor can scatter incident light to larger angles compared with the spherical YAG:Ce phosphor of the same size. In turn, their different scattering and absorption characterizations cause that the mixing concentration of the phosphors has a significant effect on the correlative color temperature and light output power of the pcLED.