Impact of the packaging structural geometry on the conformal coating LED performance by optical simulation

The conformal coating phosphor converted white light emitting diodes (pc-WLED) is one of the important high power white LED. The LED packaging structure is critical for the pc-WLED optical performance. In this paper, the impact of the five conformal coating pc-WLED packaging structure and its corresponding process design parameters on the LED optical performance was studied comprehensively. Firstly, the five optical models of the conformal coating pc-LED were built. The impact of the position deviation of the LED chip on the LED optical performance was investigated, respectively. The results show for the model III, model IV and model V the position deviation of the chip has less influence on the LED performance. Secondly, the influence of the phosphor extinction coefficient and quantum conversion efficiency on the LED optical performance has also been simulated for mode II and mode III. It is shown that the phosphor optical coefficient has great influence on the LED optical performance. The conclusion is helpful for the pc-WLED packaging structure design and process design.