Study-on-High-power-LED-Heat-Dissipation-Based-on-Printed-Circuit-Board-外文文献.doc

StudyonHighpowerLEDHeatDissipationBasedonPrintedCircuitBoardWANGYiwei,ZHANGJianxin,NIUPingjuan,LIJingyi(1.SchoolofInformationandCommunicationEngineering,TianjinPolytechnicUniversity,Tianjin300160,CHN;2.TianjinGongdaHiYuSolidStateLightingCo,Ltd.Tianjin300160,CHN)Abstract:Inordertostudytheroleofprintedcircuitboard(PCB)inhighpowerLEDheatdissipation,asimplemodelofhighpowerLEDlampwasdesigned.Accordingtothislampmodel,somethermalperformancessuchasthermalresistancesoffourtypesofPCBandthechangesofLEDjunctiontemperatureweretestedunderthreedifferentworkingcurrents.TheobtainedresultsindicatethatLEDjunctiontemperaturecannotbeloweredsignificantlywiththedecreasingthermalresistanceofPCB.However,PCBwithlowthermalresistancecanbematchedwithsmallervolumeheatsink,soitishopefultoreducethesize,weightandcostofLEDlamp.Keywords:highpowerLED;printedcircuitboard(PCB);substrateofheatdissipation;thermalresistance;junctiontemperatureCLCnumber:TN312Documentcode:AArticleID:1007-0206(2010)02/03-0120-051.IntroductionLightEmittingDiode(LED),asonekindofsolidlightemittingsemiconductordevices,haslotsofperformanceadvantages,suchaslowvoltage,highluminousefficiency,longlifetime,etc.Itisconsideredasthemostvaluablelightsourceinthe21stcentury,whichwillreplaceincandescentlamps,halogenbulbsinthefuture.HighpowerLED(≥1W)canonlyconvertabout15%oftheinputpowerintolight,withtherestbeinglostasheat.Becausethesurfaceareaofthechipissmall(only1mmx1mm~2.5mmx2.5mm),theheatfluxofthechipwillreachupto100W/cm2,anditwillrisewiththeincreaseoftheinputpower.Iftheheatcannotbeimmediatelytransferredtotheambient,thejunctiontemperatureincreases,whichwillaffecttheextractionefficiency,lightwavelength,devicelifetimeandreliabilitysignificantly.Therefore,thejunctiontemperatureoftheLEDisanimportantindexforthermalperformance.TheheatofhighpowerLEDlampisprimarilydissipatedbywayofconduction,thatis,fromPNjunctiontoepitaxiallayer,epitaxiallayertothePCB,thenPCBtoheatsink,andfinallytoairbyconvection.Therefore,PCBisnotonlyusedforphysicalsupportingandel