Patent ID: 6426785
Filing Date: 2002-07-30
Classification: G02F

Abstract:
A reflective liquid crystal display device comprising:a first transparent substrate having an outer side and an inner side, a transparent electrode and an alignment layer being provided on the inner side of the first substrate in that sequential order; a second substrate having an outer side and an inner side, a metallic reflective electrode and an alignment layer being provided on the inner side of the second substrate in that sequential order; a liquid crystal cell, in which nematic liquid crystal as a liquid crystal layer is filled, provided between the alignment layers of said first and second substrates; two polymer films provided outside of said first transparent substrate; and a polarization film provided outside of said polymer films; wherein the twist angle of said nematic liquid crystal is selected between 220Â° and 260Â°, the product of the birefringence of said nematic liquid crystal &Dgr;nLC and the thickness of said liquid crystal layer dLC, &Dgr;nLCÂ·dLC is set to be between 0.6 &mgr;m and 1.2 &mgr;m; a birefringence difference is between âˆ’0.1 &mgr;m and âˆ’0.2 &mgr;m as determined by &Dgr;(R)=(RFilm(1)+RFilm(2))âˆ’&Dgr;nLCÂ·dLC which is defined by using the retardation of said polymer film, designated as RFilm(i)=(nx(i)âˆ’ny(i))Â·dFilm(i) (i=1,2) in which 1 indicates the one of the two polymer films positioned closer to said liquid crystal cell, 2 indicates the other of the two polymer films, nx(i) (i=1,2) indicates an extraordinary index of refraction of the inside of each polymer film, ny(i) (i=1,2) indicates an ordinary index of refraction of the inside of each polymer film, dFilm(i) (i=1,2) indicates a thickness of each polymer film and &Dgr;nLCÂ·dLC; &phgr;F1âˆ’&phgr;LC satisfies 90Â°Â±20Â°, &phgr;F2âˆ’&phgr;F1 satisfies 45Â°Â±20Â° and &phgr;Pâˆ’&phgr;F2 satisfies âˆ’45Â°Â±20Â°, wherein when the reflective liquid crystal display device is seen from the side of said first transparent substrate, the twist direction of the liquid crystal is designated as the positive direction of rotation, an angle is measured using the horizontal direction as a standard, &phgr;LC designates the angle of the alignment direction of the liquid crystal molecule on said transparent substrate positioned at the upper side, &phgr;F1 indicates the angle of the direction of retardation axis of the polymer film positioned at the side of said liquid crystal cell, &phgr;F2 indicates the angle of the direction of retardation axis of the polymer film positioned at the side of said polarization film, and &phgr;P indicates the angle of the direction of the adsorption axis of the polarization film.