Efficiency improvement of power LED modules using a hybrid aluminum nitride substrate

This study combined experimental and theoretical analysis to investigate the hybrid aluminum nitride (AlN) substrate that can effectively improve efficiency and heat dissipation of multi-chip LED modules. The experimental results showed that hybrid AlN substrate can effectively reduce the thermal resistance from junction to substrate ∆R_js by 46% compared with metal core printed circuit board (MCPCB) as driving current increased from 0.6 A to 1.6 A. Under the rated current of 1.2 A, the R_js and chip temperature of the AlN module was approximately 0.73 K/W and 10 °C lower than that in the MCPCB module. Compared to MCPCB, the hybrid AlN substrate also had 25% higher luminous flux at 1.2 A. Simulating results provided insight understanding of temperature distribution inside the LED modules and showed good consistency with experiments. Additionally, the decreasing rate of substrate temperature (T_s) outside the chips in AlN LED module is higher than in MCPCB LED module. This study demonstrated that the hybrid AlN substrate is a reliable and a cost effective design that can effectively improve both efficiency and heat dissipation of high power LED modules.