A comparative study of phosphor scattering model for phosphor-converted light-emitting diodes

In phosphor-converted light-emitting diodes (pc-LEDs), phosphor heating can lead to decrease of luminous efficiency or even thermal quenching due to local high phosphor temperature. Phosphor scattering model has been used to calculate the phosphor heat generation. Using this model, there are two methods for heating power estimation, one is the subtractive method and the other is the integral method. In this work, we conducted comparative study of these two methods. We found the heating power of integral method is lower than that of the subtractive method. Phosphor heat generation measurement was performed and results showed that the experimental data agreed well with the subtractive method. Finite element model (FEM) was used to evaluate the phosphor temperature by inputting the calculated heating power. Higher phosphor temperature was obtained by the subtractive method due to relative higher heat load. Infrared thermal test verified that the measured phosphor temperature was close to that of the subtractive method. Therefore, the phosphor scattering model using the subtractive method can be applied for accurate phosphor heating and temperature estimation.