半导体照明的挑战

1ChallengesinSemiconductorLightingsFromEpitaxy,Chip…toApplicationQunZhong钟群CenturyEpitechCo.,LTD世纪晶源科技有限公司ShenzhenNationalSemiconductorLightingsEngineeringIndustrializationBase深圳国家半导体照明工程产业化基地2Thehistoryofhigh-brightnessLEDapplicationsTrafficSignalPilotLamps(consumerproducts)3Thehistoryofhigh-brightnessLEDapplicationsMobileApplicationFullColorDisplay4Thehistoryofhigh-brightnessLEDapplicationsBacklightforLargeDisplaysAutomotiveApplication5Thehistoryofhigh-brightnessLEDapplicationsGeneralIlluminations6ComparisonbetweenLEDLightings&ConventionalLightings90-95100120135n/aLED（2012）80-90507290n/aLED（2008）441560-90100-150400LowPressureSodiumVapor252050-8090-140400HighPressureSodiumVapor70-851066110400MetalHalide70-8515457575MetalHalide50203050250MercuryLight65-885357015CompactFluorescentLamp65-88825505CompactFluorescentLamp50-9012549058FluorescentTube50-9010488028FluorescentTube98-100291850Tungsten-halogen98-100361210Tungsten-halogen98-10017.51560Incandescent98-100251015IncandescentCRI（%）Lifetime（khrs）SystemL/E（lm/W）LuminousEfficacy（lm/W）Power（W）LampType7ChallengestoimplementationofLEDlightingsapplications•LuminousEfficacy•Lifespan•Heatdissipationmanagement•Radiationpattern•Coloruniformity•ColortemperatureadjustableTheabovechallengeswillbecometheadvantagesiftheproblemsaresolved.8LuminousEfficasy---InProgress9ImproveluminousefficacyOBJECTIVE:luminousefficacy﹥150lm/W,OR,Wallplugefficiency50%Wallplugefficiency=Internalquantumefficiency´Extractionefficiency´PowerefficiencyInternalquantumefficiency:50%↗70%ExtractionEfficiency:50%↗80%PowerEfficiency:85%↗90%1011EpitaxyChallenges12?!Lowrefractiveindexnanocoating(silicananorods)980%#2+Photoniccrystal+MicrocavityLEDs840%MicrocavityLEDs750%#2+Photoniccrystal640%Flip-Chip546%#2+Surfaceroughing440%#1+Surfaceroughing330%Thinfilmtechnology–substrateremovement+Highlyreflectivemetallization（√）225%Thickconductivewindowlayer（√）1ExtractionEfficiencyTechniques#Challengetoimproveextractionefficiency(encapsulantmaterialrefractiveindex=1.5)IfencapsulantmaterialRI=2.2!!!13兰宝石N-GaN透明电极P电极P-GaNN电极NormalLEDChipStructure14VertivalStructureLEDChipSiCGaNN电极P电极15Flip-chipLEDChipSiSubmount380±40um250umN-metalSolderAreaSapphireSubstrateN-typeGaNEpiN-metallizationP-typeGaNEpiP-MetallizationP-MetalSolderAreaSolderSumps16PhotoniccrystalLEDChipCathodebondingpadPatternedsurfaceHighefficiencymirrorreflectorMetalAlloyVerticalPhotons4-5umthinEpi-layers17PackagingLEDforLightingApplicaionslSinglechippackagevs.multiplechippackage(COB)noyesLightInterferencelowhighLuminousEfficacyAttention!minorGlareProblemgoodgoodReliabilityhighlowYieldcomplicatedsimpleProductionProcessnoyesColorBinningeasydifficultHeatDissipationMultiplechippackageSinglechippackage18DifferentTypesofWhiteLEDs1.TheinternalquantumefficiencyforgreenLEDandtheextractionefficiencyforredLEDareverylow.2.LightlossduetoStokesShift.3.GoodtosmartLEDlighting---colortemperatureadjustable.HighLowDifficult(UVLED)HighHighUVLED+RGBPhosphorLowHighEasyLowHigh[2]BlueLED+YellowPhosphorLowHighDifficult(needmixingoptics)HighLow[1]RGBLEDMixture[3]CostReliabilityFabricationCRIEfficiencyMethods19Spectraforwhitefrom3000Kto7500KattestcurrentatT=25℃(BlueLEDChip+Yellow/RedPhosphor)020406080100120350400450500550600650700750Wavelength(nm)RelativeIntsnsity(%)7500K6500K5500K4500K3500K3000K20PackagingLEDforlongtermperformance•LEDChipMaterial•EncapsulantMaterial:UVresistant•EncapsulantMaterial:watervaporproof•Lifetimevs.Tj(LEDPNjunctiontemperature)100000455250065850005045000707000055375007560000603000080Lifetime(hrs)Tj(℃)Lifetime(hrs)Tj(℃)21Lifetimetest---1WLEDLumenOutputvs.Timefor1WLED00.20.40.60.811.20200040006000Time(hrs)RelativeLumenOutput45C-145C-245C-370C-170C-270C-3100C-1100C-2Analysis:45C-1representsTj=45ºC;70C-1representsTj=70ºC;100C-1representsTj=100ºC.Accordingtodetailedcalculation,lumenoutputdegradationafter50,000hrswillbe:15%whenTj=45ºC;25%whenTj=70ºC;50%whenTj=100ºC.22PackagingLEDforlongtermperformancelHeatsinking23PackagingLEDforlongtermperformancelOpticsDesign24ColorTemperatures•ANSI&SSLC78.377(bluishwhite)8000K9Daylight6530±510K6500K8（coldwhite）5665±355K5700K7(naturalwhite）5028±283K5000K64503±243K4500K5Coolwhite3985±275K4000K4White3465±245K3500K3Warmwhite3045±175K3000K22725±145K2700K1CommentTargetCCT&ToleranceNominalCCTCode25WhitecoloruniformityColorTemperaturevs.ForwardCurrentforWhiteLEDs2500300035004000450050005500600065007000750080000100200300400500ForwardCurrent(mA)ColorTemperature(K)3000K3500K4500K5500K6500K26AdvantagesofCNEPILEDLightingsGenerallyAcceptedbyMarketPartlyAcceptedbyMarketCostStandardization(indevelopment)PWMLinearAdjust90%85%PowerDriveStandardization(indevelopment)Thermal-electricinterconnectionΔTj15KΔTj25KHeatDissipationCreationnovalstructureImitationoftraditionallightsLightingFixture9085ColorRenderIndexFull-rangeFull-rangeColorTemperatureExcellentQuitegoodWhiteColorUniformity130lm100lmHighPowerLED(I=350mA)7lm(white)5lm(white)TopviewSMDLED(I=20mA)100000hrs50000hrsLifetime(30%degradation)100lm/W70lm/WSystematicLightingEffi