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沈阳工程学院毕业设计（论文）-1-BasedonAT89C52LEDoverviewLED(LightEmittingDiode),light-emittingdiode,isasolidstatesemiconductordevices,whichcanbedirectlyconvertedintoelectricitytolight.LEDistheheartofasemiconductorchip,thechipisattachedtooneendofastent,isthenegativeside,theotherendofthepowerofthecathode,theentirechippackagetobeepoxyresin.Semiconductorchipiscomposedoftwoparts,partoftheP-typesemiconductor,itinsidethehole-dominated,theothersideistheN-typesemiconductor,hereismainlyelectronic.Butlinkingthetwosemiconductors,amongthemtheformationofaPNjunction.Whenthecurrentthroughthewiresroleinthischip,willbepushinge-P,Pzoneintheholewithelectroniccomposite,andthentobeissuedintheformofphotonenergy,andthisistheprincipleofLEDluminescence.Thewavelengthoflightthatisthecoloroflight,isformedbythePNjunctionofthedecisionsofthematerial.LEDhistory50yearsago,peoplehavetounderstandsemiconductormaterialscanproducelightofthebasicknowledge,thefirstcommercialdiodesin1960.EnglishistheLEDlightemittingdiode(LED)acronym,anditsbasicstructureisanelectroluminescentsemiconductormaterials,placedinawirerack,thensealedwithepoxyresinaround,thatis,solidpackage,Therefore,theprotectionoftheinternalbatteriescanplaytheroleofline,sotheseismicperformanceLEDgood.LEDisthecoreoftheP-typesemiconductorandcomponentsoftheN-typesemiconductorchips,theP-typesemiconductorandN-typesemiconductorbetweenatransitionlayer,calledthePNjunction.InsomesemiconductormaterialsinthePNjunction,theinjectionofasmallnumberofcarrier-carrierandthemajorityoftheextratimewillbeintheformoflightenergytorelease,thusthepowertodirectconversionofsolarenergy.PNjunctiononreversevoltage,afewhard-carrierinjection,itisnotluminous.Thisuseofinjectionelectroluminescentdiodesisproducedbytheprincipleoflight-emittingdiodes,commonlyknownasLED.Whenitinapositivestateofthework(thatis,atbothendswithforwardvoltage),thecurrentflowsfromtheLEDanode,cathode,semiconductorcrystalsontheissuefromtheultraviolettoinfraredlightofdifferentcolors,lightandthestrengthofthecurrents.InstrumentsusedforthefirstLEDlightsourceinstructions,butallkindsoflightcoloredLEDlightsintrafficandlargescreenhasbeenwidelyapplied,haveaverygoodeconomicandsocialbenefits.The12-inchredtrafficlightsasanexample,isusedintheUnitedStateshavelonglife,low-efficiency140wattincandescentlampasalightsource,itproduced2,000lumensofwhitelight.Theredfilter,theloss-90percent,only200lumensofredlight.Inthelightofthenewdesign,Lumiledscompanieshave18redLEDlightsource,includingthelossofcircuit,atotalpowerconsumptionof14wattstogeneratethesameopticaleffect.AutomotiveLEDlightsisalsothesourceofimportantareas.沈阳工程学院毕业设计（论文）-2-Forgenerallighting,peopleneedmorewhitelightsources.The1998whiteLEDsuccessfuldevelopment.ThisistheGaNLEDchipandYttriumAluminumGarnet(YAG)packagetogethercause.GaNchipoftheBlu-ray(λp=465nm,Wd=30nm),madeofhigh-temperaturesinteringoftheCe3+YAGphosphorsexcitedbythisBlu-rayafterirradiatingayellow,thepeak550nm.Blue-chipinstalledintheLED-basedWanxingreflectioninthecavity,coveredwitharesinmixedwithYAGthinlayer,about200-500nm.LED-basedtabletsissuedbytheBlu-rayabsorptionpartofthephosphor,thephosphoranotherpartoftheBlu-rayandayellowlightmixed,canbeawhite.Now,theInGaN/YAGwhiteLED,YAGphosphorbychangingthechemicalcompositionofthephosphorlayerandadjustthethicknessofthe3500-10000Kcolortemperaturecanbecoloredwhite.ThisblueLEDthroughthemethodbywhite,constructedsimple,low-cost,hightechnologyismature,sousethemost.Inthe1960s,theuseofscienceandtechnologyworkerssemiconductorPNjunctionofTheprincipleofdevelopingaLEDlight-emittingdiodes.Atthattime,thedevelopmentofLED,thematerialsusedareGaASP,itsluminouscolorisred.Afternearly30yearsofdevelopment,andnowweareveryfamiliarwiththeLED,hasbeensenttored,orange,yellow,green,blue,andothershade.HoweverlightingnecessaryforwhiteLEDlightonlyinrecentyearstodevelop,readersheretotellusaboutlightingwithwhiteLED.TheLEDdisplayscreenandvideodisplayintothetextbyLEDmatrixblocks.Graphicdisplaycanbedisplayedwithcomputer,English,Chinesetextandgraphics,Videoscreenusingmicrocomputercontrol,graphic,image,withreal-time,synchronization,clearinformationdisseminationwayplayallkindsofinformation,butalsoshows2d,3danimation,videos,TV,VCDprogramsandlive.TheLEDdisplayscreendisplaybrightcolors,stereosenseisstrong,suchasoil,suchasfilms,widelyusedinfinance,taxation,industryandcommerce,telecommunications,sports,advertising,corporations,transportation,educationsystem,station,port,airport,hospital,shoppingmalls,hotels,Banks,securitiesmarket,market,andconstructionmanagementofindustrialenterprises,Christie'sandotherpublicplaces.TheLEDdisplaycandisplaythechangeofdigitalimage;text,graphics,Notonlycanbeusedforindoorenvironmentcanalsobeusedinoutdoorenvironment,projectors,LCDTVwall,andtheincomparableadvantages.LEDbythewideattentionandrapiddevelopment,anditistheadvantagesofitself.Theseadvantagesinis:highbrightness,workingvoltage,lowconsumption,miniaturization,impactresistanceandlongservicelifeandstableperformance.LEDthedevelopmentprospect,iscurrentlytowardsahigherbrightness,higherresistanceto