主动式矩阵液晶显示器-Part.-I

FundamentalsofAMLCD(I)FundamentalsofAMLCD(I)Reporter:Chao-yiChen2012/09/17OutlineOutline•Introduction•ColorTFT-LCDStructure•BasicOperationPrinciplesOutlineOutline•Introduction•ColorTFT-LCDStructure•BasicOperationPrinciplesIntroductionIntroduction
DiscoveryofLiquidCrystals:In1888,F.Reinitzer(AustriaBotanist)foundamaterialwhichhastextureatparticulartemp.In1889,O.Lenhmann(GermanyPhysicist)foundthismaterialwhichhasbirefringenceproperties.CrystallineSolidIsotropicLiquidMesophasesPlasticCrystalsLiquidCrystalsGlobularPositionorderlyDirectiondisorderlyNofluidityRod-like,Dise-like…PositiondisorderlyDirectionorderlyFluidity•IntroductionofLiquidCrystalIntroductionIntroduction
Thermotropic(熱致型熱致型熱致型熱致型):Phasetransitionwithvarioustemperature–Rod-Like(桿狀)•Nematic(向列型)•Cholesterics(膽固醇型)•Smectic–Disc-like(碟狀)•Columnar•DiscoticNematic–Other•Bowlic,Banana…
Lyotropic(溶致型溶致型溶致型溶致型):Phasetransitionwithvariousconcentrationofsolvent•IntroductionofLiquidCrystalIntroductionIntroduction
Thermotropic:Mostknownliquidcrystalsareproducedbyvaryingthetemperatureofvarioussubstances(inparticular,byraisingthetemperatureofcertainsolidsorloweringthetemperatureofcertainliquids)andarecommomlytermedthermotropic.TemperatureTmpTcpLiquidCrystalIsotropicLiquidSolidCrystal•IntroductionofLiquidCrystalIntroductionIntroduction•ShapeofLCMolecule:Rod-like(Cigar-like,orCalamitic)Disc-like(Discotic)X:RigidCoreY:LinkingGroupZ:FlexibleSideChainDiscoticPhaseAnti-DiscoticPhase•IntroductionofLiquidCrystalIntroductionIntroductionNematicSmecticASmecticCCholesteric
MolecularLCArrangement:•IntroductionofLiquidCrystalIntroductionIntroduction
Lowtemperaturestabilitytest:–Eutectic(共晶點)mixture=compositionwhichhasthelowestmeltingpointthananyofitssingleconstituents–Realmixturesifcustomers=notidealeutecticbutmetastableatlowtemp.•Metastable:Unstablephasebutchangesoccurveryslowly•LCcanbesupercooled:itcanbechilledbelowitsfreezingpointwithoutitbecomingacrystal.EutecticPoint(Composition)•PhysicPropertiesofLiquidCrystalIntroductionIntroduction
DielectricAnisotropic(介電異向性介電異向性介電異向性介電異向性):Δε=ε
-ε͵(PositiveLC:Δε0;NegativeLC:Δε0)εεεε
εεεε͵͵͵͵Directionn̅̅̅̅DielectricConstantshaveinfluenceon:–ThresholdVoltage–OperatingVoltage–PowerConsumption–Resistivity&Viscosity(Indirect)•PhysicPropertiesofLiquidCrystalIntroductionIntroduction
Birefringence(複折射性複折射性複折射性複折射性):Δn=n
-n┴=ne–noZYXn
n┴┴┴┴•IndexellipsoidofnematicLC:–nZnX=nY–nX=nY=n┴–nZ=n
•PhysicPropertiesofLiquidCrystalIntroductionIntroduction
Birefringence:Δn=n
-n┴=ne–noZYXn
n┴┴┴┴LightLightneff•PhysicPropertiesofLiquidCrystalIntroductionIntroduction•PhysicPropertiesofLiquidCrystal
ElasticConstants(kii,彈性係數彈性係數彈性係數彈性係數):AlldeformationsinLCscanbedecomposedintothreemaindistortionsTwist,k22Splay,k11Bend,k33IntroductionIntroduction
RotationalViscosity(γγγγ1,旋轉黏滯係數旋轉黏滯係數旋轉黏滯係數旋轉黏滯係數):•IndicatetherotationabilityofLCmoleculeMoleculesrotatefasterwithsmallerrotationalviscosity.•Regularly,smallerrotationalviscositywithpositive(Δε0)LC.•PhysicPropertiesofLiquidCrystalIntroductionIntroductionHomogeneous
TNHomeotropic
VAAnchoringEnergy!!•LiquidCrystalMoleculesAlignmentIntroductionIntroduction
Contrast:C.R.=WhiteLum./BlackLum.0.00.51.01.52.02.53.03.54.04.55.05.56.0020406080100V-TCURVE(ZCE-5366LA-0846)TRANSMITTANCE(%)Appiledvoltage(V)-300C-200C-100C00C100C200C300C400C500C600C700C800C80°C-30°C•Electro-opticofLiquidCrystalIntroductionIntroduction
ViewingAngle:•Electro-opticofLiquidCrystalIntroductionIntroduction•Electro-opticofLiquidCrystalGray–scaleinversionGray–scaleinversionIntroductionIntroduction
SwitchingTime:•Electro-opticofLiquidCrystalIntroductionIntroduction
SwitchingTime:•Electro-opticofLiquidCrystalIntroductionIntroduction•LiquidCrystalOperatingModes•TN(TwistedNematic)•STN(SuperTwistedNematic)•DSTN(DoubleSuperTwistedNematic)•FLC(FerroelectricLiquidCrystal)•GH(Guest-Host)•DS(DynamicScattering)•PDLC(PolymerDispersedLiquidCrystal)•VA(VerticalAlignment)•IPS(In-planeSwitching)More……IntroductionIntroduction•TwistedNematicModeCFTFTLefthandedforthemostTNLCD!!!IntroductionIntroduction222222112sin21sin21uuXXT++==πφdnnuoe)(22−=Γ=λφ(1stmax)•TwistedNematicMode
NBIntroductionIntroduction222112sin2121uuT++−=πdnnuoe)(22−=Γ=λφ•TwistedNematicMode
NWIntroductionIntroduction25△△△△n0△△△△n0△△△△n0(ONstate)優點優點優點優點：：：：Highcontrastratio缺點缺點缺點缺點：：：：Graylevelinversion02thicknessilmilm=Δ+ΔffgapLCLCdndndarkstatesreducingtheleakageoflightIntroductionIntroduction•VerticalAlignmentModesAdvantage:•HighContrastRatio•WideViewingAngleDisadvantage:•ColorShift•N-typeLC•NBmodeDarkBrightIntroductionIntroduction•In-Plane-SwitchingModes2727Advantage:•Highcontrastratio•Wideviewingangle•LessretardationdependentDisadvantage:•Higherdrivingvoltage•SmallerapertureratioIntroductionIntroductionDirectdrivingMultiplexdriving•Everypixelisindependentlyaddressed•EverypixelhasaconnectionforaN×Mdisplay，thereareN×Melectricalconnections•Forlowerresolutionsonly•CanaddressN×MpixelsusingonlyN+Melectricalconnections•MatrixDrivingIntroductionIntroductionStorageCapacitorTFT(SwitchingDevice