Optimal substrate design for thermal management of high power multi-chip LEDs module

Abstract

The use of light emitting diodes (LEDs) for lighting requires high level of thermal management. In fact, the lamp is more efficient when operating under lower junction temperature. In this paper, we present a three dimensional analysis of 106 W multi-chip LEDs lamp using finite element method. A comparison between two different substrate designs was carried out and showed that using separated substrates (an individual substrate for each chip) ameliorates the heat transfer rate more than the case of using one continuous substrate for all chips. The design of separated substrates was then optimized taking into account the substrate dimension, the spacing between adjacent chips and the number of chips on each substrate. It was found that using the optimal design of separated substrates instead of continuous one leads to a decrease of 14.38% of the junction temperature, an amelioration of 11.82% of the light output and an augmentation of 105212 h in the lamp lifetime.