LED Light文章 2.docx
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LED Light文章 2.docx
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LEDLight文章2
1.HowToChooseASuitableLedDisplay
TherearesomanyLEDdisplaymanufacturershereinChina.thereisasaying:
60%~70%LEDdisplayaremadeinChina,and60%~70%LEDdisplaysaremadeinShenzhen,China.buttillnow,noonecanshowthevaliddataabouttheinformation.luckly,IaminShenzhen,andengagedinthisfieldfornearly2years.
Sometimes,it'smoredifficultbuyingthanselling.(sorry,iamnotgoodatEnglish)ImetcustomersfromUSA,Poland,Iran,Turkeyetc,generallyspeaking,theyspentabout1weekinChina.andtheyvisitedmorethan10factorieshere,thatmeans,theyvisited1.5factorieseveryday,average.that'snotaeasyjob,everyfactorywillgiveyoudifferentinformation,it'sabigproblemthathowyougettheusefulandcorrectinformation.iamsure,whatsuppliersgiveyouisnotalwayscorrectallthetime,becausewhomyoudiscusswithisalwayssalesman,andsomesalesmandon'tknowverywellaboutthisindustrythemselfes,foranotherword,theyarenotprofeesional.butthatnotmeansthefactorynotprofessional.inShenzhen,China,manyownersoffactory,theyhavebeeninvolvedinthisfieldformorethan10years,theyarepioneers.also,theyaredemosticsalesmanyearsago.butabigproblemistheycan'tspeakenglish,luanguageisbigobstacleforthem.takemybossforexample,heengagedinthisfieldformorethan10years,heknowsverywellaboutthisindustry,buthecan'tjointhediscuss.sometimes,ourcustomeraskedme,whereisyourboss?
isaid:
sorry,heisnotgoodatenglish.itwillbemuchbetterifdiscusswithmyboss.ithappens.
Ok,letgettothepoint,howtochooseasuitableLEDdisplay.maybeisaoldtopic.butasfarasiknow,manyfriendshavenoideaaboutthisbeforetheycametoChina.ichoosetheword"suitable",not"good".becausedifferentcustomerhasdifferentrequirement.gooddoesnotmeansuitable,butsuitabledoesmeansgoodforyou.
italwaysconsideredasaprojectwhenyouwantbuyaLEDdisplay.soyoushouldhaveabudgetonit,100,000,80,000USD?
somethinglikethis.then,it'sthedetailsaboutyourproject,suchas:
1.wherewillbetheLEDdisplayinstalled?
indoororoutdoor?
2.whatmessagecontentisneeded?
videos,photos,orjustcharacters?
3.whatdimensionwillbeyourscreen?
width,height?
4.whatwillbetheminimalviewingdistancefromyourscreentotheclosestspectators?
5.what'sthedistancefromLEDscreentocontrolsystem?
6.what'stheinstallationtype?
inlay,pole,orsomethingelse?
aftertheseinformation,youcangetageneralsolutionfromthesupplier.forexample,youwantanoutdoordisplayforaddisplaying,viewingdistanceisabout17meters,youprepare100,000USDforit,andthesuppliermayrecommendP16,CreeLEDchips,40squaremeters.ok,thissolutionsoundsgood,thenyoumaywannacheckthequality,thisismostimportantforyou.youdon'twantspend100USDforapieceofpaper.so,howtojudgethequality,maybeyoucanconsiderbasedonbelowinformation:
KeyFactors:
1.Smoothness(plantnessonsurface)
Keepthesmoothnesswithin1millimetertoinsuretheimagenotbeencurved.itdependsonassembletech.
2.Brightness
ForindoorLEDdisplay,itshouldbemorethan800cd/sq.mandforoutdoor,itshouldbemorethan1500cd/sqm.Ifbrightnesstoolow,theimagewillbetotallyvague.brightnessdependsonLEDlampsyouadoptandotherfactors
3.viewingangle
generallyspeaking,foroutdoordisplays,viewingangleforhorizontalisabout110degree,andforverticalis90degree.thelargerthebetter.
4.whitebalance.
Toshowapurewhitecolor,theratioofRGBis3:
6:
1,wacthifthereisblueorredcolorinwhitecolor.ThisfactormostlydependsoncontrolsystemandLEDlamps
5.colorrestorable.
ThecoloronLEDscreenshouldconsistwithdisplayresourcestokeepagoodimage.
6.malfuncationdot,mosaic
makesurethereisnodeaddotandmosaicondisplay
ThesefactorsareveryimportantwhenchooseaLEDdisplay,it’sdiffeculttomaintenanceforsomeunprofessionalcustomers.
2.ImproveTheThermalStructureOfWhiteLightLedLife
PastledindustrywhotoprofitfullofwhitelightLEDbeam,haddevelopmentlargesizeLEDfloodlightschiptriestobythiswayreachedexpectedtarget,butactuallywhitelightLEDofimposedpowercontinuedover1Wabovetimebeaminsteadwillfell,glowefficiencyisrelativereduced2030%,inotherwordswhitelightLEDofbrightnessiftothantraditionalLEDlargenumbertimes,consumptionpowercharacteristicshopebeyondFireflylightlampwords,onrequiredfirstovercomefollowingoffourtopics,including,suppressiontemperaturerose,andensureusinglife,andImprovementofluminousefficiencyandphotoluminescenceofequalization.
Theproblemoftemperatureriseofthespecificmethodistoreducethethermalresistanceofthepackage;maintenanceofBlueLEDstripthelifeofaspecificmethod,istheimprovementofchipshape,smallchip;improvingtheLEDluminousefficiencyofspecificmeasuresistoimprovethestructure,asmallchipchip;improvementofluminescentcharacteristicsofuniformmethodsisLEDpackagingmethods,andinthedevelopmentofthesemethodshavecometobe.
Thermalproblemisthefundamentalwaytosolvepackage
Duetoincreasedpowerinsteadwillcausedpackageofhotimpedancesharplyfellto10K/Wfollowing,soabroadindustrywhohaddevelopmentresistancehightemperaturewhitelightLEDtriestobythisimproveaboveproblem,howeveractuallypowerLEDpanelofheatisthansmallpowerLEDhighdozensoftimestimesabove,andtemperaturerosealsowillmakesglowefficiencysharplyfell,evenpackagetechnologyallowshighheat,butLEDchipofjunctiontemperatureishasmayoverallowedvalue
Finallyfinallylearnedtosolvethermalproblemsistherootofthepackage.
AboutLEDofusinglife,suchasinsteadSiliconmasspackagematerialandceramicpackagematerial,canmakesLEDofusinglifeimproveonenumber,especiallywhitelightLEDofglowspectrumcontainswavelengthbelow450nmshortwavelengthlight,traditionalepoxyresinpackagematerialveryeasyisshortwavelengthlightdamage,highpowerwhitelightLEDoflargelightvolumemoreacceleratedpackagematerialofbadof,underindustrywhotestresultsdisplayedcontinuouslightdoesnotto10,000hours,highpowerwhitelightLEDofbrightnesshasreducedhalfabove,Doesnotmeetthebasicrequirementsforlightingandlonglife.
AboutLEDofglowefficiency,improvechipstructureandpackagestructure,arecanreachedandlowpowerwhitelightLEDsamelevel,maincausesiscurrentdensityimprovetwicetimesaboveShi,notonlydoesnoteasyfromlargechipoutlight,resultsinsteadwillcausedglowefficiencythanlowpowerwhitelightLEDofdilemma,ifimprovechipofelectrodeconstructed,theoryoncansolutionabovetakelightproblem.
Seekstoreducethethermalresistance,improvetheheatsinkproblem
Aboutluminescentcharacteristicsofuniform,GeneralbelievesthatimprovingtheconcentrationoffluorescentwhitelightLEDmaterialuniformityandfluorescenttechnology,shouldbeabletoovercometheseproblems.Asmentionedabovewhileimprovingpowerimposed,musttrytominimizethermalimpedance,improvedheatdissipation,andspecificcontentinthereportare:
reducingthechiptothethermalresistanceofthepackage,containthepackagethermalresistance,improvethechiptoprintedcircuitsubstrateheatsinkofsmooth.
Totoreducedhotimpedance,manyabroadLEDmanufacturerswillLEDchipsetincopperandceramicmaterialmadeofthermalfintablets(heatsink)surface,receivedsthenwithweldingwaywillprintedcircuitboardShangthermalwithwire,connectiontousingcoolingfanforcedemptycoldofthermalfintabletsShang,underGermanyOSRAMOptoSemiconductorsGmbexperimentalresultsconfirmed,abovestructureofLEDchiptoweldingpointsofhotimpedancecanreduced9K/W,aboutistraditionalLEDofOne-sixtharound,packageHouofLEDimposed2WofpowerShi,LEDchipofjunctiontemperaturethanweldingpointshigh18K,evenprintedcircuitboardtemperatureroseto500C,junctiontemperatureatmostonly700Caround;phasethanXiapasthotimpedanceoncereducedwords,LEDchipofjunctiontemperatureonwillwasprintedcircuitboardtemperatureofeffect,sothenrequiredmanagedtoreducedLEDchipoftemperature,inotherwordsreducedLEDchiptoweldingpointsofhotimpedance,caneffectivereduceLEDChipcoolingburdenofthejob.ContraryevenwhitelightLEDhassuppressionhotimpedanceofstructure,ifheatcannotfrompackageconductiontoprintedcircuitboardwords,LEDtemperatureroseofresultsglowefficiencywillsharplyfell,soPanasonicelectricaldevelopmentprintedcircuitboardandpackageintegrationtechnology,thecompanywill1mmsquareofBlu-rayLEDtoflipchipwaypackageinceramicbaseboardShang,receivedsthenwillceramicbaseboardpasteincoppermassprintedcircuitboardsurface,underPanasonicsaidcontainsprintedcircuitboardzaineimoduleoverallofhotimpedanceaboutisAbout15K/W.
Showthermaldesignpower
DuetothermalfintabletsandprintedcircuitboardZhijianofkeyssexualdirectlyaroundhotconductioneffect,soprintedcircuitboardofdesignbecameverycomplex,hasprisonYuthisUnitedStatesLumiledsandJapanCITIZEN,lightingdevice,andLEDpackagemanufacturers,havedevelopmenthighpowerLEDwithsimplethermaltechnology,CITIZENin2004begansamplesshipmentsofwhitelightLEDpackage,doesnotneedsspecialjunctiontechnologyalsotowillthickabout23mmthermalfintabletsofheatdirectlyemissionstoexternal,undertheCITIZENsaidalthoughtheLEDchipjunctiontoheatthermalimpedancethantheOSRAM9K/Wfin30K/W
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