Heat dissipation performance for the application of light emitting diode

This study was to design and develop the efficient heat dissipation methods for light emitting diode (LED). There are two major achievements in the study: (1) Chips level: Improve the LED packaging materials and layers assembly of LED. This novel design was to introduce additional thin copper layer materials on LED base assembly with geometry that can reduce thermal resistance and increase thermal diffusion efficiency. The design was then being calculated on its heat transfer behavior using simulation with 3-D finite element method. The experimental and simulation results of various packaging area parameters were presented with respect to 0.75W, 1W and 3W LED chips. Both experimental and simulation results show close agreement that through the design of additional packaging arrangement it can reduce the thermal equilibrium temperature of LED. It was found that the addition of 9cm2 copper-packaged area improves the thermal dissipation of LED, resulting in a reduction of chip temperature lower 5°C than non-packaging pattern. (2) System level: Design and develop heat pipe structures as heat sink for a LED illuminator set. The experiments were conducted to investigate the cooling characteristics of heat pipes by changing working fluid mass and working angle. Additionally, both discrete hotspot of LED and central heating of heat pipe were studied. The results of heat pipe experiments show that when the experimental set of LED illuminator was used in horizontal angles, resulting in the heat pipe which fills 2.52g water volume has the best thermal properties than others. Resulting in the heat source temperature maintain in 50°C. Whereas others have higher temperature results due to the steam inside pipe choked. The experiment and simulation results show in this study provide very useful contributions for the application of heat dissipation for LED both in chip level packages and system level performance.