LED Light文章 2.docx

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