TFTLCD制造流程及光学规格介绍

TFT-LCD模组結構組成TFT-LCD工作原理TFT-LCD製作流程簡介TFT-LCD光學規格介紹,TFT-LCD簡介及光學規格介紹,ThinFilmTransistorLiquidCrystalDisplay薄膜電晶體液晶顯示器,WhatsTFT-LCD,Thethin-filmtransistorliquidcrystaldisplay(TFT-LCD)isacutting-edgedisplay,whichscreenspictureinformationbyadjustingtheamountoflightpermitted.TFTisacircuitformedwithsemiconductorfilmsonathinglasssubstratetocontrolliquidcrystals.Thiscircuitplaysavitalroleincontrollingeachpixel,thebasicunitofapictureimage.Thecolorfilterdisplaysacolorimagebycoatingthepixel(red,greenandblue)onaglasssubstrate.,DriverIC,Cell,TFT-LCDpanel,Backlight,Frontview,Backview,X-PCB,LampConnector,DriverIC,TimingController,SignalInterface,Y-PCB,LVDSreceiver,TFT-LCD模组結構組成,关于液晶,1888年，澳大利亚植物学者莱尼茨尔（Reinitzer）研究胆甾醇在植物中的作用时，用胆甾基苯进行试验，无意间发现了液晶，但液晶的实际应用直到二十世纪五十年代才开始。顾名思义，液晶是固液态之间的一种中间类状态。液晶是一种有机化合物，在一定的温度范围内，它既具有液体的流动性、粘度、形变等机械性质，又具有晶体的热（热效应）、光（光学各向异性）、电（电光效应）、磁（磁光效应）等物理性质。光线穿透液晶的路径由构成它的分子排列所决定。人们发现给液晶充电会改变它的分子排列，继而造成光线的扭曲或折射。液晶按照分子结构排列的不同，分为三种：晶体颗粒粘土状的称为近晶相（Smectic）液晶、类似细火柴棒的称为向列相（Nematic）液晶、类似胆固醇状的称为胆甾相（Cholestic）液晶。这三种液晶的物理特性都不尽相同，用于液晶显示器的是第二类的向列相（Nematic）液晶,TFT-LCD工作原理,Apixel,thesmallestunittoindicateapictureimage,isformedbythreesub-pixelsconsistingofred,green,andblue.ThenumberofpixelsarrangedinadisplaydeterminestheresolutionoftheTFT-LCD.TFTiscomposedofthedataline(imagesignaltransfer)andgateline(TFTon/offsignaltransfer).TFTexistingineachsub-pixelcontrolsthevoltagedifferencebetweentheTFTglasselectrodeandthecolorfilterglasselectrodeinordertoadjustthemoleculararrayofliquidcrystals.Suchachangeinthemoleculedirectionofliquidcrystalsalterstheamountoflightpenetratingtheliquidcrystallayer.Consequently,theTFT-LCDdisplayshowspictureimageinformation.,TFT-LCD工作原理,液晶是一种有机复合物，由长棒状的分子构成。在自然状态下，这些棒状分子的长轴大致平行。LCD第一个特点是必须将液晶灌入两个列有细槽的平面之间才能正常工作。这两个平面上的槽互相垂直(90度相交)，也就是说，若一个平面上的分子南北向排列，则另一平面上的分子东西向排列，而位于两个平面之间的分子被强迫进入一种90度扭转的状态。由于光线顺着分子的排列方向传播，所以光线经过液晶时也被扭转90度。但当液晶上加一个电压时，分子便会重新垂直排列，使光线能直射出去，而不发生任何扭转。LCD的第二个特点是它依赖极化滤光片和光线本身，自然光线是朝四面八方随机发散的，极化滤光片实际是一系列越来越细的平行线。这些线形成一张网，阻断不与这些线平行的所有光线，极化滤光片的线正好与第一个垂直，所以能完全阻断那些已经极化的光线。只有两个滤光片的线完全平行，或者光线本身已扭转到与第二个极化滤光片相匹配，光线才得以穿透。LCD正是由这样两个相互垂直的极化滤光片构成，所以在正常情况下应该阻断所有试图穿透的光线。但是，由于两个滤光片之间充满了扭曲液晶，所以在光线穿出第一个滤光片后，会被液晶分子扭转90度，最后从第二个滤光片中穿出。另一方面，若为液晶加一个电压，分子又会重新排列并完全平行，使光线不再扭转，所以正好被第二个滤光片挡住。总之，加电将光线阻断，不加电则使光线射出。当然，也可以改变LCD中的液晶排列，使光线在加电时射出，而不加电时被阻断。但由于液晶屏幕几乎总是亮着的，所以只有加电将光线阻断的方案才能达到最省电的目的。,TFT-LCD工作原理,TFT-LCD工作原理,TFT-LCD製作流程,TFT-LCD製作流程TFTProcess,TFT-LCD製作流程TFTProcess,TFT-LCD製作流程TFTProcess,processandprocessingstepsarequitesimilartothatofthesemiconductorindustry.Deposition,photolithographyandetchingstepsarecommontobothindustries.ThekeydifferencesarethattheTFTisbuiltonaglasssubstrateinsteadofasiliconwafer.Inaddition,theTFTrequiresaprocessingtemperaturerangingfromapproximately300to500?comparedtoabout1,000?requiredforsemiconductorfabrication.1.PECVD(PlasmaEnhancedChemicalVaporDeposition)ProcessBeforegasentersthechamber,thestateofthevacuumismaintainedandtheglassplateisheatedtoaspecifictemperature.Whengasflowsintothechamber,theRFvoltageisappliedfromelectrodesinsidethechamber,whichtransformgasintoaplasmastate.Fromthisplasma,precursorsareformedanddepositedontheglasssubstrate.2.SputteringProcessSputteringistheprocesswhereinthegasion,whichisthehighenergyinsidetheplasmacreatedbyRFpowerorDCpowercollideswiththetargetsurface,resultinginthedepositionofthetargetmaterialontheplate.Generally,thetargetmaterialsaremountedonthenegativeelectrodesurface.Then,thesputteredtargetmaterialsaredepositedontheplate,whichisputonthepositiveelectrode.Forsputtering,inactivegasesareused,suchasheliumandargon,sothatdepositionmaterialchemistryisnotaffected.,3.PhotolithographyProcessPhotolithographyisthetransferofapatternfromthephotomaskontoasubstrate.Thephotolithographyprocessbeginswhenthesubstrateiscoatedwithanextremelythinliquidfilmofphotosensitivematerial,calledphotoresis.Thelightthenexposesthephotoresist,someofwhichisdestroyedwhenexposedtothelight.Theunnecessaryportionofthematerialisthencleanedfromthesurfacethroughanotherprocess,leavinganextremelyfinepatternbehind.Anotherlayerofthephotoresististhendepositedtothesubstrate,exposed,cleaned,untilallthelayershavebeenprintedorimagedontothesurface.ThephotolithographyprocessisacriticalstepwithintheLCDmanufacturingprocessbecausepanelqualitydependsontheentirepatternformation.Assuch,itisextremelysensitivetoparticlesandotherformsofcontamination.Thus,thisprocessrequiresaspecialcleanenvironment,commonlyreferredtoasacleanroom,andprecisecontrolofequipment,chemicalsandmaterials.Inthefuture,thiswillproveincreasinglyimportantasadvanceddisplaysthatoffergreaterfunctionalityandhigherperformancewillrequireincreasinglycomplexandstringentmanufacturingcapabilities.4.DryetchProcessThedryetchprocessusesreactivespecies,suchasatomsorradicalsfromthegasplasma,toetchawayaportionoftheobjectmaterial.Whenthesespeciesreactwiththemateriallocatedontheplate,theopenregionofmaterialtransformsintoavolatilestateandisremovedfromthematrix.Inthisprocess,thereactionvelocityisfastandfinepatternscanbeformeduniformly.,TFT-LCD製作流程ColorFilterProcess,TFT-LCD製作流程CellProcess,LCDproductionprocesscanbedescribedasfollows:(1)theorientationlayeronthelowerandupperplateisformed;(2)thelayerisproperlypositionedsothattheliquidcrystalcanproperlyalign;(3)thespacerisdispensed,thesealisprinted,andthetwoplatesareassembled;(4)theliquidcrystalisinjectedintothecellthroughthecapillaryeffect;and(5)theinjectionholeissealed.1.PrintingtheOrientationLayerTheorientationlayerisevenlyspreadonthepixelareaoftheupperandlowerplate.Thepolyimideisspreadonthedrumthinlyandevenlyandiscoatedontherubberplate,whichhasbeenpatternedinadvance.Inturn,thepolyimideisprintedontheuppercolorfilterorthelowerTFT-arrayplate.Afterprinting,thepolyimideishardenedthroughtheprocessofannealing.2.RubbingRubbingistheprocessthatformsthestraightgrooveonthehardenedpolyimideinafixeddirectioninordertomaketheliquidcrystalorientinafixeddirection.Thestraightgroovecanbeformedbyrubbingthepanelinacertaindirectionwiththerubbingvelvetattachedtotherotatingdrum.,3.DispensingSpacersThespacersaredispensedevenlyinordertosecurethefixedcellgapwhenassemblingtheupperandlowerplate.Afterthespacersaremixedintheliquidwiththeproperconcentration,theyarethentransportedtothespraynozzlethroughthepump,andsubsequentlysprayedonthesurfaceoftheplatefromthenozzlewithhighpressure.Heatingdriestheliquid,andthedensityofthespacerisadjustedbetween100ea/and200ea/accordingtothedisplaysize.Thespacershapeislikeaballwithadiametersizebetween4and5whichdeterminesthecellgapbetweentheplates.4.InjectingtheLiquidCrystalTheliquidcrystalisinjectedbetweentheupperandlowerplateusingcapillaryactionandpressuredifferencesaftertheupperandlowerplateareassembled.Theprocesssystemconsistsofavacuumpump,vacuumchamber,anup/downmovingdevice,ajig,whichcontainstheliquidcrystal,and,anNsystem.Atfirst,theinternalcellvacuumlevelismaintainedatabout10-3Torrfromtheoriginalvacuumstate.Theliquidcrystalisthenpulledintothecellbythecapillaryeffect.Whenthecellisfilledwithliquidcrystaluptoabout80percent,N?sthenpurgedintothevacuumchamberslowlyandtheliquidcrystalfillstheremainingspaceinthecellasaresultofthedifferenceinpressurefrominsideandoutsidethecell.,TFT-LCD製作流程ModuleProcess,Themoduleprocessisthestepthatdeterminesthefinalqualityoftheproducttobedeliveredtothecustomer.Thestepiscompletedoncethepolarizer,thedriveIC,PCB,backlightunitandtheframeareassembled.,亮度Luminance(cd/m2),TFT-LCD重要光學規格,10mm,10mm,10mm,10mm,1/4H,1/2H,3/4H,1/4V,1/2V,3/4V,Y1,Y11,Y5,Y4,Y2,Y12,Y13,Y8,Y7,Y6,Y3,Y9,Y10,a.規格條件：(1)中心點(2)五點平均b.影響亮度的因素(1)Cell穿透率(开口率)(2)GammaCurve(3)BL發光效率(4)燈管電流,2.對比度ContrastRatio(CR),TFT-LCD重要光學規格,LuminanceofallpixelsWhite(L255)LuminanceofallpixelsDark(L0),L255(orL63),L0,CR=,3.分辨率,TFT-LCD重要光學規格,LCD的最大分辨率就是它的真实分辨率，也就是最佳分辨率。,4.ViewingAngle(可视角),TFT-LCD重要光學規格,CR10(W/B),液晶显示器的可视角度包括水平可视角度和垂直可视角度两个指标：水平可视角度表示以显示器的垂直法线(即显示器正中间的垂直假想线)为准，在垂直于法线左方或右方一定角度的位置上仍然能够正常的看见显示图像，这个角度范围就是液晶显示器的水平可视角度；同样如果以水平法线为准，上下的可视角度就称为垂直可视角度。一般而言，可视角度是以对比度变化为参照标准的。当观察角度加大时，该位置看到的显示图像的对比度会下降，而当角度加大到一定程度，对比度下降到101时，这个角度就是该液晶显示器的最大可视角。一般主流LCD的可视角度为120160度。比较理想的可视角度应在175度以上（水平