Study on Thermal Conductivity of Micro-arc Alumina Substrate for High Power LED

Substrate heat dissipation is the main way of heat dissipation of LED chip, and improving its heat dissipation performance is the key to solving the heat dissipation of high-power LED. In this paper, 10-40μm oxide film was grown in situ on the surface of 2024 aluminum alloy as the insulating layer of insulating metal substrate (IMS) by micro-arc oxidation. 3W LED lamp beads are used as heat sources to be packaged on the traditional heat-dissipating substrate and micro-arc alumina substrate. The temperature difference and thermal resistance on both sides of the packaging substrate when the LED lamp works normally are measured by temperature measuring device. The heat dissipation performance of different packaging substrate and the heat conduction effect of micro-arc alumina substrate with oxide film thickness of 10-40μm are studied under the condition of satisfying the unity and standardization of the experimental conditions. Experiments show that:(1) Under the constant current of 600 mA, the temperature difference of the micro-arc alumina substrate is reduced by 511 °C compared with the conventional heat-dissipating substrate, and the thermal resistance of the substrate is reduced by 40%-60%; (2) The thermal resistance of the micro-arc alumina substrate decreases with the decrease of the thickness of the micro-arc oxide film layer. When the film layer is 10μm, the thermal resistance of the substrate is reduced by 10%-40% compared with other thicknesses.