Impact of the LED chips placement and heat sink design on the multi-chip LED bump performance by the thermal and optical simulation

For the high power LED light resource, it is reasonable to integrate several low power LEDs to improve the total output luminous. The layout of the low power chips and heat sink used has importance influence on the optical performance and the temperature distribution of the multi-chip LED packaging. But previous literatures mailing focused on the optical performance and temperature distribution respectively, few articles had studied both integrately. Firstly, the 3D model of the LED lamp was built in the PRO/Engineer software. The finite element model of the LED lamp was obtained and the temperature distribution was analyzed in ANSYS Workbench software. Then the uniformity of illumination of the multi-chip LED bump packaging was modeled in the Tracepro and DIALux. The impact of the three critical parameters of the LED bump, such as the distance of the multi-chips, the number and the thickness of the heat sink bins, on the optical performance was investigated. Lastly, the optimization of the above three critical parameters was solved with the Uniform Design Experimentation method and GA algorithm. The optimization result shows that the temperature of the high power packaging optimized is about 58.4°C, which is decreased by 30% from the original design and the uniformity of illumination is increased by 4 % compared with the original design.