LED的发展与应用

江苏恩洋光电科技股份有限公司LightEmittingDiode2017/1/26Contents1.History2.Application3.Epitaxy4.Fabrication5.Packaging6.OLED7.FutureThehistoryoflightingandLEDInancienttimes,therewerenolamps,sopeoplecouldonlyusefireforlighting.candlekerosenelampPeoplesteppedintotheworldoflight.ThefirstgenerationoflightingincandescentlampsIncandescentlampswerewidelyusedbecauseoftheextensiveapplicationofelectricity.ThesecondgenerationoflightingNow,fluorescentlampsarethemostwidelyused.ThethirdgenerationoflightingFluorescentlampscompactfluorescentlampLEDisthefourthgenerationoflighting.ThedevelopinghistoryofLEDsTheapplicationofLEDLEDsignallightsStreetLightsA—LEDStreetLightsB—MetalHalideStreetLightsC—SodiumStreetLampsSolarStreetLampsAirportrunwaylightingandLEDtunnellampsAutomotiveApplicationwithLEDsLEDinteriorlightingBarLandscapeLightingMobileApplicationWithLEDsLEDScreenDisplayThepaintedscrollismadeupof44,000LEDs.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-basedLEDSubstrate(siliconorsapphire)AlNsufferlayern-typeSi-dopingGaNMulti-quantumwellp-typeMg-dopingGaNverticalstructureofepitaxialwafersiliconepitaxialwafersapphireepitaxialwaferFabricationHundredsofthousandsofLEDchipsareproducedononeepitaxialwafer.LEDchips1mm2Multi-quantumwells(MQW)verticalstructureofepitaxialwaferBluelightcomesfromMQW,whereisalsocalledactiveregion.CanwemakeLEDelectrodeswithverticalstructure?1.Theanswerdependsonthesubstrate.2.Theverticalstructurewillcausehighresistance.3.Itisnotgoodforfabricationwhenthetwoelectrodesareatdifferentsides.PhotoetchingandICPetchingP-electrodeandn-electrodearemadeatthesameside.ICP:InductivelyCoupledPlasmaTransparentelectrodeevaporationSincep-GaNlayerisinhighresistance,weneedtoevaporatetransparentelectrodetoimprovecurrentspreading.Theelectrodeisasthinasabout12nm,soitistransparent.LEDchiplateralstructureLEDchipVSverticalstructureLEDchipDifferentp-electrodestructuresToimprovecurrentspreadingandluminousefficiencyLEDchipsinourlabThemechanismofLEDbalancedstateThemechanismofLEDForwardvoltageisapplied.ThemechanismofLEDElectronsandholesrecombinetoemitlight.ThedevelopmentofLEDpackagingLEDPackagingTogettheinputsignalToprotecttheLEDchipsTogettheoutputofvisiblelightPurposeforpackaging1.PintypepackagingTwomainmethodsofLEDpackaging2.PlanarpackagingHowtomakewhiteLED?LEDissinglecolor,suchasred,yellow,green,blueandsoon.However,whiteismixedcolor.SoweneedtomixcolorstomakewhiteLED.TwomainmethodsofmakingwhiteLED1.blueLED+yellowphosphor=whiteLED2.red+green+blue=whiteOLED=OrganicLightEmittingDiodeItslight-emittingmechanismissimilartoLED.OLEDThestructureofOLEDAccordingtolight-emittingmaterials:SmallmolecularOLED:Alq3(八羟基喹啉铝)PolymerOLED(PLED)：PPV,MEH-PPVAccordingtodisplaymodels:PassiveMatrix(PM-OLED):AcitiveMatrix(AM-OLED):TFTFOLED:FlexibleOLEDClassification1.Thicknesscanbelessthan1mm.2.Lowcost;Simpleprocess;(30~40%).3.Self-luminous;Highlyefficientandkindtoenvironment.4.Lowdrivevoltageandlowpowerconsumption.5.Microsecondresponsetime(1000times)andwideperspective(170°).6.Highbrightness(100~14000cd/m2),widetemperaturerange(-30~80℃)Advantages1.Lifeisusuallyonly5,000hours,lessthanthatofLCDatleast1millionhours.2.Colorpurityisnotenoughtoshowbrightandrichcolor.3.Large-sizeOLEDpanelproductionhasverylowyield(30%),comparedwithLCD’s(99%).4.Highpatentfees.DisadvantagesComparedwithIPhoneViewfromside(LG‘sfirstOLEDtelevision)FirstOLEDwirelessdigitalphotoframeofKODAKFirstOLEDnotebookintheworld(SUMSUNG)ApplicationBracketlightMilitarydisplayE-book;E-magazine;E-newspaperTVanddisplayhead-mounteddisplayApplicationI’MCUTE!MynameisLED.Firstly,Iamsmaller.Secondly，Ineedlesspower.Thirdly，Ienjoylongerlife.Atthesametime，youcancallmeenergysavinglamp.It’slastbutnottheleast,I’mafashiongirl.ThefutureofLEDWhenitcomestomyweakness,mypriceistoohigh.Andthen,myluminousfluxislow.Stroboscopicphenomenon.Strongstimulation.MyweaknessMyfutureisbright!Withthedevelopmentoftechnologyandthereductionofcost,Iwillbethemostpopularintheworld!