LED的发展与应用.ppt

LED,LightEmittingDiode,2017/1/26,Contents,HistoryApplicationEpitaxyFabricationPackagingOLEDFuture,ThehistoryoflightingandLED,Inancienttimes,therewerenolamps,sopeoplecouldonlyusefireforlighting.,candle,kerosenelamp,Peoplesteppedintotheworldoflight.,Thefirstgenerationoflighting,incandescentlamps,Incandescentlampswerewidelyusedbecauseoftheextensiveapplicationofelectricity.,Thesecondgenerationoflighting,Now,fluorescentlampsarethemostwidelyused.,Thethirdgenerationoflighting,Fluorescentlamps,compactfluorescentlamp,LEDisthefourthgenerationoflighting.,ThedevelopinghistoryofLEDs,TheapplicationofLED,LEDsignallights,StreetLights,ALEDStreetLightsBMetalHalideStreetLightsCSodiumStreetLamps,SolarStreetLamps,AirportrunwaylightingandLEDtunnellamps,AutomotiveApplicationwithLEDs,LEDinteriorlighting,BarLandscapeLighting,MobileApplicationWithLEDs,LEDScreenDisplay,Thepaintedscrollismadeupof44,000LEDs.,TheOlympicringsaremadeupof2,000blueand44,794whiteLEDs.,Epitaxy,Thefirstgenerationmaterials:Si,Ge;Thesecondgenerationmaterials:GaAs,InP,GaP,InAs,AlAs;Thethirdgenerationmaterials:SiC,ZnAs,GaN,diamand.,Epitaxialgrowthtechnology(GaN-basedmaterials),MOCVD(metalorganicchemicalvapordeposition)MBE(molecularbeamepitaxy)HVPE(hydridevaporphaseepitaxy),Thechoiceofsubstratematerials,Sapphirecommonused,fabricationmaturity,lowprice;largelatticedismatch,poorelectricconductivity,poorthermalconductivity.SiCsmalllatticedismatch,goodelectricconductivity;highprice.Silowprice,bigarea,highquality,goodelectricconductivity;largelatticedismatch.,TheepitaxialstructureofGaN-basedLED,Substrate(siliconorsapphire),AlNsufferlayer,n-typeSi-dopingGaN,Multi-quantumwell,p-typeMg-dopingGaN,verticalstructureofepitaxialwafer,siliconepitaxialwafer,sapphireepitaxialwafer,FabricationHundredsofthousandsofLEDchipsareproducedononeepitaxialwafer.,LEDchips1mm2,Multi-quantumwells(MQW),verticalstructureofepitaxialwafer,BluelightcomesfromMQW,whereisalsocalledactiveregion.,CanwemakeLEDelectrodeswithverticalstructure?,1.Theanswerdependsonthesubstrate.2.Theverticalstructurewillcausehighresistance.3.Itisnotgoodforfabricationwhenthetwoelectrodesareatdifferentsides.,PhotoetchingandICPetching,P-electrodeandn-electrodearemadeatthesameside.,ICP:InductivelyCoupledPlasma,Transparentelectrodeevaporation,Sincep-GaNlayerisinhighresistance,weneedtoevaporatetransparentelectrodetoimprovecurrentspreading.Theelectrodeisasthinasabout12nm,soitistransparent.,LEDchip,lateralstructureLEDchip,VS,verticalstructureLEDchip,Differentp-electrodestructures,Toimprovecurrentspreadingandluminousefficiency,LEDchipsinourlab,ThemechanismofLED,balancedstate,ThemechanismofLED,Forwardvoltageisapplied.,ThemechanismofLED,Electronsandholesrecombinetoemitlight.,ThedevelopmentofLEDpackaging,LEDPackaging,TogettheinputsignalToprotecttheLEDchipsTogettheoutputofvisiblelight,Purposeforpackaging,1.Pintypepackaging,TwomainmethodsofLEDpackaging,2.Planarpackaging,HowtomakewhiteLED?,LEDissinglecolor,suchasred,yellow,green,blueandsoon.However,whiteismixedcolor.SoweneedtomixcolorstomakewhiteLED.,TwomainmethodsofmakingwhiteLED,1.blueLED+yellowphosphor=whiteLED,2.red+green+blue=white,OLED=OrganicLightEmittingDiodeItslight-emittingmechanismissimilartoLED.,OLED,ThestructureofOLED,Accordingtolight-emittingmaterials:SmallmolecularOLED:Alq3(八羟基喹啉铝)PolymerOLED(PLED)：PPV,MEH-PPVAccordingtodisplaymodels:PassiveMatrix(PM-OLED):AcitiveMatrix(AM-OLED):TFTFOLED:FlexibleOLED,Classification,Thicknesscanbelessthan1mm.Lowcost;Simpleprocess;(3040%).Self-luminous;Highlyefficientandkindtoenvironment.Lowdrivevoltageandlowpowerconsumption.Microsecondresponsetime(1000times)andwideperspective(170).Highbrightness(10014000cd/m2),widetemperaturerange(-3080),Advantages,Lifeisusuallyonly5,000hours,lessthanthatofLCDatleast1millionhours.Colorpurityisnotenoughtoshowbrightandrichcolor.Large-sizeOLEDpanelproductionhasverylowyield(99%).Highpatentfees.,Disadvantages,ComparedwithIPhone,Viewfromside(LGsfirstOLEDtelevision),FirstOLEDwirelessdigitalphotoframeofKODAK,FirstOLEDnotebookintheworld(SUMSUNG),Application,Bracketlight,Militarydisplay,E-book;E-magazine;E-newspaper,TVanddisplay,head-mounteddisplay,Application,IMCUTE!,MynameisLED.Firstly,Iamsmaller.Secondly，Ineedlesspower.Thirdly，Ienjoylongerlife.Atthesametime，youcancallmeenergysavinglamp.Itslastbutnottheleast,Imafashiongirl.,ThefutureofLED,Whenitc