Thermal modeling of specialty heat-sinks for low-cost COP packaging of high-power LEDs

We report on the 3D modeling and simulation of specialty heat sink designs for Chip on Plate (COP) packaging of high power UV LEDs. Steady state thermal analyses for COP packaged devices were carried out by using finite element code (FEM). Two different sets of heat-sinks such as plate fins, pin fins and fin/pin type varying in numbers and dimensions were modeled to calculate the junction temperature (Tj) of each heat sink respectively. Comparative study showed that the selected geometries and dimensions of these heat-sinks have significant effect on the device junction temperatures. Furthermore, thermal circuit model (TRC) was also used to calculate the junction temperatures for these -heat sinks. For this, both conductive and convective thermal resistances were also taken into consideration. We found that the TRC results were in good agreement with the FEM modeled data. For best plate fin heat-sink, the junction temperature was around 37°C whereas it was ~41°C for less efficient plate heat-sinks. Finally, the junction temperature for the high density pins heat-sink and the low-density fins heat sink was estimated as 33°C and 46°C respectively.