Patent ID: 6229587
Filing Date: 2001-05-08
Classification: G02F

Abstract:
A color liquid crystal display apparatus comprising:a liquid crystal layer of a nematic liquid crystal having positive dielectric anisotropy and including a chiral material, which is interposed between two substrates disposed substantially in parallel to each other, each provided with a transparent electrode and an aligning layer wherein the twist angle of the liquid crystal layer by the orientation of liquid crystal molecules determined by the aligning layer of each of the substrates is 160.degree.-300.degree.;a pair of polarizing plates disposed outside the liquid crystal layer; anda driving circuit for applying a driving voltage across the transparent electrodes, wherein in said color liquid crystal display device:a birefringent plate is disposed between the liquid crystal layer and either one of the pair of polarizing plates;in the two substrates, the substrate adjacent to the birefringent plate is a first substrate and the other is a second substrate, and a product .DELTA.n.sub.1.multidot.d.sub.1 of a refractive index anisotropy .DELTA.n.sub.1 of the liquid crystal in the liquid crystal layer and a thickness d.sub.1 of the liquid crystal layer is 1.2 .mu.m-2.5 .mu.m:the birefringent plate is so formed as to have a relation of n.sub.x.gtoreq.n.sub.z.gtoreq.n.sub.y wherein n.sub.x and n.sub.y respectively represent a refractive index (n.sub.x >n.sub.y) in the direction of film plane of the birefringent plate, and n.sub.z represents a refractive index in the direction of thickness of the birefringent plate (except for a case of n.sub.x =n.sub.z =n.sub.y);in the birefringent plate, a sum .DELTA.n.sub.2.multidot.d.sub.2 of the refractive index anisotropy between a slow axis (a direction of n.sub.x in the film plane) and a fast axis (a direction of n.sub.y in the film plane), and a birefringence in the vertical direction corresponding to the thickness is 1.2 .mu.m-2.5 .mu.m; andat least three kinds of voltage are selected as to be applied across the transparent electrodes by multiplexing driving.