两种热电分离式基板导热性能的对比研究

Comparative Study on Heat Dissipation Performance of Two Thermal-Electric Separation Substrates

基于热电分离式设计理念,开发出FR4/Cu与FR4/AlN两种高导热散热基板,并利用SMT工艺将13 W的Osram S2W型LED灯珠分别与上述两种散热基板焊接后组装成LED模组;利用半导体制冷温控台恒定散热基板底部温度后,使用结温测试仪对LED的结温进行了测试。同时借助直流电源和积分球分别对LED的总功率和光功率进行了测量后得到了模组的热功率值。最后根据LED结温测试结果与热功率值计算得出了模组的热阻值,并在此基础上对两种基板的散热性能进行了对比研究。结果表明,FR4/AlN基板的散热性能较之FR4/Cu基板稍逊。当使用FR4/Cu基板散热时,LED的结温和热阻分别是49.72℃、2.21℃/W。当使用FR4/AlN基板散热时,LED的结温和热阻分别是51.32℃、2.32℃/W。

On the base of thermos-electric separation concept,FR4/Cu substrate and FR4/AlN substrate,which were expected to be high thermally conductive,were fabricated and then mounted with 13 W Osram S2W LEDs employing SMT technology to prepare LED modules.The LED’s junction temperature was evaluated employing junction temperature tester with the temperature on the bottom side of the above mentioned substrates fixed constant by semiconductor refrigeration temperature control platform.The LED’s thermal power was obtained by measuring their total power values and radiant power values using DC Power and integrating sphere respectively.After that,a comparative study on the heat dissipation performance,characterized by module’s thermal resistance in relation with LED’s junction temperature and thermal power,between FR4/Cu and FR4/AlN substrates was performed.It was found that FR4/Cu substrate presents a slightly better heat dissipation performance than FR4/AlN substrate does.That is when FR4/Cu substrate and FR4/AlN substrate were used as heat dissipation substrate respectively,the junction temperatures were 49.72℃and 51.32℃and the thermal resistances were 2.21℃/W and 2.31℃/W correspondingly.