A comparison study on thermal characterization of high power leds with different ceramic attach adhesives for automotive lighting applications

In general, the increased electrical current used to drive head lamp LEDs has focused more attention on the thermal paths in the packages. Consequently, the increase in the heat flux can cause thermal runaway and catastrophic failures, limiting the full exploitation of the LED chip technology. The present study aims to develop highly thermal conductive composite materials, based on aluminium nitride (AlN) epoxy composites, as ceramic attach thermal adhesive layer for high power LEDs. Two different polymer matrices were employed to compound the AlN filled epoxy composites; bisphenol-A diglycidyl ether (D1) epoxy resin and a cycloaliphatic compound (Cl). Comparing D1 and C1 with the control glue system, it was found that control glue performed the best. D1 performed the worst with highest thermal resistance in the application. The material properties of the glues and the thermal transient measurement of head lamp LEDs are discussed extensively in this paper.