Abstract
Thermal management of high power LED (Light Emitting Diode) is divided into internal and external parts. The internal thermal management discusses the problem between LED chip and thermal structure. Low thermal resistance of package structure will improve the heat dissipation. Otherwise, the external management discusses heat transfer phenomenon between heat sink and ambient. High power LED heat transfer behavior is derived in this research using one- and two-stage thermoelectric cooler. According to simulations, Si is chosen to be LED packaging material. This study utilizes MEMS fabrication to define the electrode and flip chip bonding is used to finish LED package. Temperature of LED is measured by IR scope. Simulations of heat transfer behavior of LED package and thermoelectric cooler is achieved to predict the temperature of LED by the software, ANSYS. In this part, the optimized pitch of the LED array is 3.8mm. Decreasing the height of thermoelectric leg from 2.5 to 1.9mm, the performance of thermoelectric cooler is increased. When the pitch of LED array is 3.8mm, spreading resistance is derived from the comparison of theory and simulation results. Finally, a 2×2 LED array is arranged with 3.8mm pitch and fixed by silver epoxy. After that, the LED chip is wire bonded in series. Temperature of LED chip is measured by IR scope. The measurement results are consistent with the trend of simulations, which show a good agreement.