| dc.description.abstract |
White LED is an important candidate of new generation solid state lightening. Understanding the mechanism of how is the interaction between current, light and heat is an essential task for us. In this study, finite element method (FEM) and Monte Carlo statistics method are applied to optical-electrical-thermal coupled numerical model. Obtaining the light source from IQE calculation. Coupling with the phosphor packaging numerical model in order to analyze the temperature distribution, light output power, CCT, and CRI of phosphor-converted white LED.
The blue LED and yellow phosphor is chosen as the material of white LED. The packaging with and without phosphor are investigated. From the comparison, the result obtained from numerical simulation can correctly fit to the experimental result. The self-heating of phosphor layer is the main reason that caused the hotspot in phosphor layer for phosphor-converted white LED.
Based on the previous analysis, double phosphor layer packaging was proposed. The concentration of inner layer is always higher than outer layer, and the CCT of white LED is set to be about 6300K. With higher inner concentration, the absorption of die is enhanced, caused the color shift and higher junction temperature. Lower inner concentration can lead to lower junction temperature, however the maximum temperature of phosphor layer is higher as an exchange, due to the heat generation mostly happened at outer layer. Based on these analysis of simulation, better LED device is expected to be realize. | en_US |