Patent ID: 6351299
Filing Date: 2002-02-26
Classification: G02F

Abstract:
A liquid crystal display device comprising:a pair of spaced apart substrates; each of said substrates being alignment treated such that a direction of said alignment having a slight angle of inclination to said substrate and being substantially parallel to each other; a cholesteric liquid crystal layer disposed between said pair of substrate, having an intrinsic helical pitch of approximately twice as large as a spacing between said substrates, to constitute a liquid crystal cell; said cholesteric liquid crystal layer having a bistable character capable of switching bistable states by an application of voltage such that a twist angle of said liquid crystal layer along the direction of a thickness thereof being either approximately 360Â° or an angle subtracted 360Â° from the approximately 360Â°; a pair of polarizers each provided on an upper face and lower face of said liquid crystal cell; and at least one birefringent medium layer further provided between said polarizer and said substrate at least for either one of an upper or lower set of said polarizer and said substrate, to reduce a birefringence effect thereof at one of said bistable states, wherein said birefringent medium layer is nearly uniaxial, having a slow axis in the plane of the birefringent medium layer and a &Dgr;nd value of said birefringent medium layer is approximately equal to that of said liquid crystal cell, and an approximately right angle between a slow axis of said birefringent medium layer and an alignment direction of the face of the liquid crystal opposing to the birefringent medium layer.