Optimization of Arrangement of LED on the PCB for High Power LED Module

Abstract

LED operating under high-temperature condition badly affects reliability. To reduce junction temperature of LED is crucial. In this paper, luminous intensity and photo conversion efficient with respect to electrical power are discussed. Moreover, three arrangements for LED module are suggested, and design parameters are discussed in terms of the number of LEDs and distance between each LED. In order to evaluate thermal performance of designed the module, computer simulation was conducted. Distance between each LED is selected by 7.6, 9.6, and 13.3mm for 80, 128, and 240 LEDs, respectively and unit heat flux is calculated to be 0.47W/mm2 , 0.29W/mm2 , 0.16W/mm2 for 80, 128, and 240 LEDs, respectively. In this case, Maximum temperature on the PCB was 67.8C, 62.5C, and 57.1C for 80, 128, and 240 LEDs, respectively. The Maximum temperature and unit heat flux was reduced by 15.7% and 66%, respectively, when the number of LEDs are increased by three times. We found that the temperature between LEDs can be reduced if unit heat flux can be reduced.