Thermal characterization of high power LED array in aluminum base copper clad laminate package

With the increasing power of a single LED chip and the requirement of more LED chips in one package for high illumination, the conventional LED lamps with the surface mound device-printed circuit board (SMD-PCB) package have met some troubles. In the SMD-PCB package, there has too many thermal interfaces and hence has very high thermal resistance from chip to heat sink, which bring the high junction temperature in the LED chips. In this paper, we have proposed a new chip-on-board package structure which has used the aluminum base copper clad laminate as the package substrate. The LED chips are directly bonded on the aluminum based and there has no insulation layer between the LED chips and the metal base. The forward voltage method is used to measure the junction temperature (Tj) of the active LED chips. The Tj of the chips in the new package is found to be 21°C lower than that in the traditional package. The proposed package of chip-on-board LED structure has showed excellent thermal properties.