Comparative analysis of thermal and optical properties for the LEDs with different circuit boards

We have fabricated three types of high power LEDs with different circuit boards: Al2O3 ceramic board, epoxy PCB with Cu-deposited on the wall of holes and epoxy PCB with Cu-filled through holes. The different contribution of the package have been separated and investigated by using the derivative of temperature rise in the time domain and thermal transient method. The results show that although the thermal conductivity coefficient of epoxy PCB is much smaller than that of ceramic, PCB integrated with Cu can improve the heat-dissipation significantly and decrease the thermal resistance. In addition, this design can also improve the EQE droop effect.