| Summary: | 碩士 === 國立成功大學 === 工程科學系碩博士班 === 96 === Following the improvement in light intensity of light emitting diodes(LEDs), the automobile headlamp using LEDs is becoming a trend. The engine compartment is a high temperature environment. The temperature around is above 80℃. High temperatures will reduce the luminous efficiency and lifetime of LEDs. Thus, designing a high efficiency thermal module is important in LED headlamp application in automobiles.
In this study, the ANSYS finite element software is used to study of the thermal characteristics of an automobile headlamp using high brightness LEDs as its light source. The parameters investigated include two LED layouts (ring and distributed types), LED heat sink area, thickness and different connecting conditions. The simulation results show that different layouts exhibit nearly the same temperature distributions. The heat sink areas and thickness effect are significant only when the convective coefficient is less than 50W/m2•K. Using high thermal conductivity slugs and substrates can lower the junction temperature. Experimental results show that using four kinds of thermal modules lead to satisfactory junction temperature which is less than 135℃ in natural convection with an ambient temperature of 80℃.
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