Optimal design of heat dissipation modules for high-power LED based on the Taguchi method

Abstract

The semiconductor component of InGaN-based blue light-emitting diodes (LEDs) emits white light when combined with a yellow phosphor mixture. However, owing to the lattice dislocations and defect points in GaN, it exhibits a high thermal resistance, which leads to heat accumulation and an increase in temperature. This is problematic as overheating causes LEDs to produce dark spots and lines and reduces the luminous flux and optical power of high-power LEDs. In this study, we propose a variety of optimal structures for heat-transfer modules and apply the proposed architectures in the assembly of high-power LED modules. First, the high-power LED substrate was coated with a film of aluminum nitride (AlN). Then, copper fins were connected to the vacant spaces in the circuit boards to increase the surface area of the heat-transfer region. The Taguchi method was used to identify the optimal substrate thickness, fin arrangement, and fin depth for the effective heat dissipation in a 12-W high-power LED. A dielectric layer was grown on the surface of the AlN film to serve as a passivation layer to insulate the patient. The passivation layer reduces the physical damage caused by thermal stress, thereby improving the service life and characteristics of heat-transfer modules. The proposed design not only yields a stable LED substrate (with low thermal stress) but also induces reliable heat transfer.