OCB模式液晶光栅的光学特性研究-豆柴文库

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OCB模式液晶光栅的光学特性研究
Introduction
OCB(OpticallyCompensatedBend)modeisaliquidcrystaldisplay(LCD)technologythatiswidelyusedinvariousapplications,especiallyinhigh-speeddisplays.OCBmodeisatwistednematic(TN)cellthatrequiresaspecificopticalalignmenttoachievehighcontrastandfastresponsetime.ThispaperpresentsastudyontheopticalpropertiesofOCBmode,specificallytheliquidcrystal(LC)opticalaxisandtheLCdirectordistribution.
LiquidCrystalOpticalAxis
TheOCBmodeusesaTNcellwithabendintheliquidcrystallayer.Thisbendcreatesaspecificopticalaxisorientationalongtheliquidcrystallayer.TheopticalaxisdirectionisperpendiculartotheLCdirectoratthetwoelectrodes,anditisparalleltotheLCdirectorclosetothecenterofthecell.TheopticalaxisisdefinedasthedirectionwheretheLCrefractiveindexishighest.
TheopticalaxisorientationdeterminesthepolarizationoflightthatcanpassthroughtheOCBcell.Whenthepolarizationdirectionoflightisperpendiculartotheopticalaxis,nolightcanpassthroughthecell.Whenthepolarizationdirectionisparalleltotheopticalaxis,thelightcanpassthroughthecellunhindered.Thisfeatureiscriticalforhighcontrastdisplays.
LCDirectorDistribution
TheLCdirectordistributionisanothercriticalfactorthataffectstheopticalpropertiesofOCBmode.ThedirectordistributiondescribeshowtheLCmoleculesareorientedinthecell.InanOCBcell,theLCdirectortiltsfromthetopelectrodetothebottomelectrodeduetothebendintheliquidcrystallayer.Thetiltangleiszeroatthetopelectrodeandincreasestothemaximumatthebottomelectrode.
ThedirectordistributionaffectstheresponsetimeoftheOCBcell.ThetiltanglegradientcreatesatorqueontheLCmoleculesthatcausesthemtotwistandalignwiththeelectricfield.Thistorqueisstrongernearthetopelectrode,wherethetiltanglegradientissteeper,andweakernearthebottomelectrode,wherethetiltanglegradientisshallower.TheresponsetimeoftheOCBcellisfasternearthetopelectrodeandslowernearthebottomelectrode.
Conclusion
Inconclusion,theopticalpropertiesofOCBmodearedeterminedbytheLCopticalaxisorientationandthedirectordistribution.TheLCopticalaxisisperpendiculartotheL