Liquid Crystal Displays. Addressing Schemes and Electro-Optical Effects

493 Pages·2010·51.42 MB·English

by  Ernst Lueder

Liquid Crystal Displays
Liquid Crystal Displays: Addressing Schemes and Electro-Optical Effects, Second Edition Ernst Lueder
© 2010 John Wiley & Sons, Ltd. ISBN: 978-0-470-74519-9
Wiley-SID Series inDisplay Technology
Series Editor:
Anthony C.Lowe
ConsultantEditor:
Michael A.Kriss
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Gheorghe Berbecel
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Gregory Crawford(Ed.)
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Fundamentals ofLiquid Crystal Devices
Deng-KeYang and Shin-Tson Wu
Introduction toMicrodisplays
David Armitage, Ian Underwood, and Shin-Tson Wu
Mobile Displays: Technologyand Applications
Achintya K.Bhowmik,Zili Li, andPhilipBos (Eds.)
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Vladimir G.Chigrinov, VladimirM. Kozenkov,and Hoi-Sing Kwok
ProjectionDisplays, Second Edition
Matthew S.Brennesholtz andEdwardH. Stupp
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Liquid Crystal Displays: AddressingSchemesand Electro-OpticalEffects, Second Edition
Ernst Lueder
Liquid Crystal Displays
ADDRESSING SCHEMES AND ELECTRO-OPTICAL EFFECTS,
SECOND EDITION
Ernst Lueder
University of Stuttgart, Germany
and Electro-Optical Consultancy, LLC, USA
Thiseditionfirstpublished2010
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LibraryofCongressCataloguing-in-PublicationData
Lueder,Ernst,1932-
Liquidcrystaldisplays:addressingschemesandelectro-opticaleffects /ErnstLueder.—2nded.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN978-0-470-74519-9(cloth)
1. Liquidcrystaldisplays.2. Liquidcrystals—Electricproperties.3. Liquidcrystals—Opticalproperties. I.Title.
TK7872.L56L842010
621.3815’422–dc22
2009049550
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
ISBN:978-0-470-74519-9
Setin10/12ptTimesbyThomsonDigital,Noida,India
PrintedinGreatBritainbyCPIAntonyRowe,Chippenham,Wiltshire
To Helen
Whose assistance andpatience made thisbook possible
Contents
Foreword xiii
PrefacetotheFirstEdition xv
PrefacetotheSecondEdition xvii
AbouttheAuthor xix
1 Introduction 1
2 Liquid Crystal Materials and Liquid Crystal Cells 3
2.1 PropertiesofLiquidCrystals 3
2.1.1 Shapeandphasesofliquidcrystals 3
2.1.2 Materialpropertiesofanisotropicliquidcrystals 6
2.2 TheOperationofaTwistedNematicLCD 11
2.2.1 Theelectro-opticaleffectsintransmissivetwistednematicLCcells 11
2.2.2 TheaddressingofLCDsbyTFTs 18
3 Electro-optic Effects in Untwisted Nematic Liquid Crystals 21
3.1 ThePlanarandHarmonicWaveofLight 21
3.2 PropagationofPolarizedLightinBirefringentUntwistedNematic
LiquidCrystalCells 26
3.2.1 ThepropagationoflightinaFre´ederickszcell 26
3.2.2 ThetransmissiveFre´ederickszcell 31
3.2.3 ThereflectiveFre´ederickszcell 37
3.2.4 TheFre´ederickszcellasaphase-onlymodulator 39
3.2.5 TheDAPcellortheverticallyalignedcell 42
3.2.6 TheHANcell 44
3.2.7 Thepcell 46
3.2.8 SwitchingdynamicsofuntwistednematicLCDs 48
3.2.9 Fastbluephaseliquidcrystals 54
4 Electro-optic Effects in Twisted Nematic Liquid Crystals 57
4.1 ThePropagationofPolarizedLightinTwistedNematicLiquidCrystalCells 57
viii CONTENTS
4.2 TheVariousTypesofTNCells 67
4.2.1 TheregularTNcell 67
4.2.2 ThesupertwistednematicLCcell(STN-LCD) 70
4.2.3 Themixedmodetwistednematiccell(MTNcell) 74
4.2.4 ReflectiveTNcells 76
4.3 ElectronicallyControlledBirefringencefortheGenerationofColour 80
5 Descriptions of Polarization 83
5.1 TheCharacterizationsofPolarization 83
5.2 ADifferentialEquationforthePropagationofPolarizedLight
throughAnisotropicMedia 91
5.3 SpecialCasesforPropagationofLight 95
5.3.1 Incidenceoflinearlypolarizedlight 95
5.3.2 Incidentlightiscircularlypolarized 97
6 Propagation of Light with an Arbitrary Incident
Angle through Anisotropic Media 99
6.1 BasicEquationsforthePropagationofLight 99
6.2 EnhancementofthePerformanceofLCCells 107
6.2.1 Thedegradationofpicturequality 107
6.2.2 Opticalcompensationfoilsfortheenhancementofpicturequality 109
6.2.2.1 Theenhancementofcontrast 109
6.2.2.2 CompensationfoilsforLCmoleculeswithdifferentopticalaxis 110
6.2.3 Suppressionofgreyshadeinversionandthepreservation
ofgreyshadestability 115
6.2.4 Fabricationofcompensationfoils 116
6.3 Electro-opticEffectswithWideViewingAngle 116
6.3.1 Multidomainpixels 116
6.3.2 In-planeswitching 117
6.3.3 Opticallycompensatedbendcells 119
6.4 MultidomainVACells,EspeciallyforTV 121
6.4.1 Thetorquegeneratedbyanelectricfield 122
6.4.2 TherequirementsforaVAdisplay,especiallyforTV 124
6.4.2.1 Thespeedsofoperation 124
6.4.2.2 Colourshift,changeincontrastandimagesticking 124
6.4.3 VAcellsforTVapplications 129
6.4.3.1 MultidomainVAcellswithprotrusions(MVAs) 129
6.4.3.2 PatternedVAcells(PVAs) 130
6.4.3.3 PVAcellswithtwosubpixels(CS-S-PVAs) 132
6.4.3.4 Celltechnologiesavoidingadelayedopticalresponse 136
–Polymersustainedalignment(PSA) 136
–Mountainshapedcellsurface 137
6.4.3.5 Thecontinuouspinwheelalignment(CPA) 139
6.5 PolarizerswithIncreasedLuminousOutput 140
6.5.1 Areflectivelinearpolarizer 140
6.5.2 Areflectivepolarizerworkingwithcircularlypolarizedlight 141
6.6 TwoNon-birefringentFoils 142
7 Modified Nematic Liquid Crystal Displays 145
7.1 PolymerDispersedLCDs(PDLCDs) 145
7.1.1 TheoperationofaPDLCD 145
7.1.2 ApplicationsofPDLCDs 149
CONTENTS ix
7.2 Guest-HostDisplays 150
7.2.1 TheoperationofGuest-HostDisplays 150
7.2.2 ReflectiveGuest-HostDisplays 154
8 Bistable Liquid Crystal Displays 159
8.1 FerroelectricLiquidCrystalDisplays(FLCDs) 159
8.2 ChiralNematicLiquidCrystalDisplays 168
8.3 BistableNematicLiquidCrystalDisplays 174
8.3.1 Bistabletwistcells 174
8.3.2 Gratingalignednematicdevices 175
8.3.3 Monostablesurfaceanchoringswitching 177
9 Continuously Light Modulating Ferroelectric Displays 179
9.1 DeformedHelixFerroelectricDevices 179
9.2 AntiferroelectricLCDs 181
10 Addressing Schemes for Liquid Crystal Displays 185
11 Direct Addressing 189
12 Passive Matrix Addressing of TN Displays 191
12.1 TheBasicAddressingSchemeandtheLawofAltandPleshko 191
12.2 ImplementationofPMAddressing 196
12.3 MultipleLineAddressing 201
12.3.1 Thebasicequations 201
12.3.2 Waveformsfortherowselection 203
12.3.3 ColumnvoltageforMLA 205
12.3.4 Implementationofmulti-lineaddressing 206
12.3.5 ModifiedPMaddressingofSTNcells 210
12.3.5.1 Decreasedlevelsofaddressingvoltages 210
12.3.5.2 ContrastandgreyshadesforMLA 212
12.4 TwoFrequencyDrivingofPMLCDs 218
13 Passive Matrix Addressing of Bistable Displays 223
13.1 AddressingofFerroelectricLCDs 223
13.1.1 TheV–t addressingscheme 225
min
13.1.2 TheV–1/taddressingscheme 226
13.1.3 ReducingcrosstalkinFLCDs 228
13.1.4 Ioniceffectsduringaddressing 228
13.2 AddressingofChiralNematicLiquidCrystalDisplays 231
14 Addressing of Liquid Crystal Displays
with a-Si Thin Film Transistors (a-Si-TFTs) 239
14.1 Propertiesofa-SiThinFilmTransistors 239
14.2 StaticOperationofTFTsinanLCD 244
14.3 TheDynamicsofSwitchingbyTFTs 252
14.4 Bias-TemperatureStressTestofTFTs 259
14.5 DriversforAMLCDs 260
x CONTENTS
14.6 TheEntireAddressingSystem 266
14.7 LayoutsofPixelswithTFTSwitches 269
14.8 FabricationProcessesofa-SiTFTs 272
14.9 AddressingofVADisplays 277
14.9.1 OvershootandundershootdrivingofLCDs 277
14.9.2 Thedynamiccapacitancecompensation(DCC) 281
14.9.3 Fringefieldaccelerateddecayofluminance 288
14.9.4 Theaddressingoftwosubpixels 292
14.9.5 Biasedverticalalignment(BVA) 295
14.10 MotionBlur 298
14.10.1 Causes,characterizationandremediesofblur 298
14.10.2 Systemswithdecreasedblur 310
14.10.2.1 Edgeenhancementforreducedblur 310
14.10.2.2 Blackinsertiontechniques 312
14.10.2.3 Scanningbacklights 313
14.10.2.4 Higherframeratesforreducingblur 315
14.10.3 Modellingofblur 320
14.11 TheOpticalResponseofaVACell 329
14.12 ReductionoftheOpticalResponseTimebyaSpecial
AddressingWaveform 334
15 Addressing of LCDs with Poly-Si TFTs 339
15.1 FabricationStepsforTop-andBottom-Gate
Poly-SiTFTs 340
15.2 LaserCrystallizationbyScanningor
LargeAreaAnneal 344
15.3 LightlyDopedDrainsforPoly-SiTFTs 345
15.4 TheKinkEffectanditsSuppression 347
15.5 CircuitswithPoly-SiTFTs 349
16 Liquid Crystal on Silicon Displays 353
16.1 FabricationofLCOSwithDRAM-TypeAnalogAddressing 353
16.2 SRAM-TypeDigitalAddressingofLCOS 355
16.3 MicrodisplaysUsingLCOSTechnology 360
17 Addressing of Liquid Crystal Displays
with Metal-Insulator-Metal Pixel Switches 363
18 Addressing of LCDs with Two-Terminal Devices
and Optical, Plasma, Laser and e-beam Techniques 373
19 Components of LCD Cells 381
19.1 AdditiveColoursGeneratedbyAbsorptivePhotosensitive
PigmentedColourFilters 381
19.2 AdditiveandSubtractiveColoursGeneratedbyReflective
DichroicColourFilters 383
19.3 ColourGenerationbyThreeStackedDisplays 385
19.4 LEDBacklights 386
19.4.1 TheadvantagesofLEDsasbacklights 386
CONTENTS xi
19.4.2 LEDtechnology 386
19.4.3 OpticsforLEDbacklights 395
19.4.4 SpecialapplicationsforLEDbacklights 405
19.4.4.1 SavingpowerandrealizingscanningwithLEDbacklights 405
19.4.4.2 FieldsequentialdisplayswithLEDbacklights 407
19.4.4.3 ActivematrixaddressedLEDbacklights 409
19.4.5 TheelectronicaddressingofLEDs 409
19.5 CellAssembly 411
20 Projectors with Liquid Crystal Light Valves 415
20.1 SingleTransmissiveLightValveSystems 415
20.1.1 Thebasicsinglelightvalvesystem 415
20.1.2 Thefieldsequentialcolourprojector 416
20.1.3 Asinglepanelscrollingprojector 417
20.1.4 Singlelightvalveprojectorwithangularcolourseparation 418
20.1.5 Singlelightvalveprojectorswithacolourgrating 418
20.2 SystemswithThreeLightValves 420
20.2.1 Projectorswiththreetransmissivelightvalves 420
20.2.2 Projectorswiththreereflectivelightvalves 421
20.2.3 ProjectorswiththreeLCOSlightvalves 422
20.3 ProjectorswithTwoLCLightValves 422
20.4 ARearProjectorwithOneorThreeLightValves 422
20.5 AProjectorwithThreeOpticallyAddressedLightValves 423
21 Liquid Crystal Displays with Plastic Substrates 427
21.1 AdvantagesofPlasticSubstrates 427
21.2 PlasticSubstratesandtheirProperties 428
21.3 BarrierLayersforPlasticSubstrates 429
21.4 Thermo-MechanicalProblemswithPlastics 430
21.5 FabricationofTFTsandMIMsatLowProcessTemperatures 435
21.5.1 Fabricationofa-Si:HTFTsatlowtemperature 435
21.5.2 Fabricationoflowtemperaturepoly-SiTFTs 435
21.5.3 FabricationofMIMsatlowtemperature 437
21.5.4 Conductorsandtransparentelectrodesforplasticsubstrates 438
21.6 TransferofHighTemperatureFabricatedAMLCDs
toaFlexibleSubstrate 438
22 Printing of Layers for LC Cells 443
22.1 PrintingTechnologies 443
22.1.1 Flexographicprinting 443
22.1.2 Knifecoating 444
22.1.3 Ink-jetprinting 444
22.1.4 Silkscreenprinting 448
22.2 SurfacePropertiesforPrinting 449
22.3 PrintingofComponentsforDisplays 455
22.3.1 Ink-jetprintedcolourfilters,alignmentlayers
andphosphorsforLEDBacklights 455
22.3.2 Flexographicprintingofalignmentlayersandofnematicliquidcrystals 456
22.3.3 PrintingofOTFTs 457
22.4 CellBuildingbyLamination 461