Thermal Analysis of High Power LED Array Packaging with Microchannel Cooler

The efficiency and reliability of solid-state lighting devices strongly depend on successful thermal management. High-brightness light emitting diodes (LEDs), as a strong candidate for the next generation general illumination applications, were developed by improving luminous efficiency and integrating multi-chips within limited areas. One of key problems is cooling in developing high power LED for illumination. This paper explores the thermal analysis of high power LED array packaging with a microchannel cooler, which is a relatively new cooling technology. The packaging structure of a high power LED array integrated with a microchannel cooler is discussed. Detailed thermal performance is analyzed using the FEA (finite element analysis) technology. The effects are discussed on the cooling of a multi-chip LED module with different internal fin geometries of module, flow velocity and its total power. Simulation results, in the form of average die temperature, show that the microchannel cooler reduces the average die temperature, and improves the heat dissipation capability of LED array. However, the results also demonstrates that, without proper design the junction temperature of the module is non-uniform across the LED array, and the downstream or central chips were hotter than the upstream or edge chips. This may accelerate thermal runaway problems and reduce the reliability of the LED arrays device. The cooling scheme is optimized by using staggered fins in our microchannel cooler to increase the heat transfer coefficient of the multi-chip LED packaging module. The result shows that the packaging structure of the microchannel cooler with staggered fins achieves good thermal performance for high power LED arrays