Liquid crystal electro-optic device with particular relationship between retardation film drawing direction and substrate edge
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorTakashi Fukui
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Abstract
A liquid crystal electro-optic device is disclosed. The liquid crystal electro-optic device is provided with means for optic compensation in order to realize black-and-white display. A high contrast black-and-white display is realized by providing two retardation films having anisotropy of refractive index for optic compensation so that an angle (a) formed by the drawing direction of one of the two retardation films and an edge line of a liquid crystal panel of the device and an angle (b) formed by the drawing direction of the other one of the two retardation films and the edge line satisfy the expressions: (a).ltoreq.90.degree.; (b).ltoreq.90.degree.; and .vertline.(a)-(b).vertline..ltoreq.40.degree..
Claims15
A liquid crystal electro-optic device comprising:
- a pair of substrates provided with electrodes thereon;
- a liquid crystal layer provided between said substrates, said liquid crystal layer comprising nematic liquid crystal having positive dielectric anisotropy and optically active substances in a helical structure of a twist angle in the range of 180.degree. to 270.degree.;
- a first retardation film having anisotropy of refractive index;
- and
- a second retardation film having anisotropy of refractive index,
- wherein an angle (a) formed by the drawing direction of said first film and an edge line of one of said substrates and an angle (b) formed by the drawing direction of said second film and said edge line satisfy the expressions:
- (a).ltoreq.90.degree. ;
- (b).ltoreq.90.degree. ;
- and .vertline.(a)-(b).vertline..ltoreq.40.degree. ;
- wherein retardations of said first and second retardation films are equal and are each less than or equal to 390 nm.
A liquid crystal electro-optic device comprising:
- a first retardation film having anisotropy of refractive index;
- a second retardation film having anisotropy of refractive index;
- and
- a pair of substrates provided with electrodes thereon and provided between said first film and said second film;
- a liquid crystal layer provided between said substrates, said liquid crystal layer comprising nematic liquid crystal having positive dielectric anisotropy and optically active substances in a helical structure of a twist angle in the range of 180.degree. to 270.degree.,
- wherein an angle (a) formed by the drawing direction of said first film and an edge line of one of said substrates and an angle (b) formed by the drawing direction of said second film and said edge line satisfy the expressions:
- (a).ltoreq.90.degree.;
- (b).ltoreq.90.degree.;
- and .vertline.(a)-(b).vertline..ltoreq.40.degree.;
- wherein retardations of said first and second retardation films are equal and are each less than or equal to 390 nm.
A liquid crystal electro-optic device comprising:
- a pair of substrates provided with electrodes thereon;
- a liquid crystal layer provided between said substrates, said liquid crystal layer comprising nematic liquid crystal having positive dielectric anisotropy and optically active substances in a helical structure of a twist angle in the range of 180.degree. to 270.degree.;
- a first retardation film having anisotropy of refractive index provided on one of said substrates;
- and
- a second retardation film having anisotropy of refractive index provided on said first film,
- wherein an angle (a) formed by the drawing direction of said first film and an edge line of one of said substrates and an angle (b) formed by the drawing direction of said second film and said edge line satisfy the expressions:
- (a).ltoreq.90.degree.;
- (b).ltoreq.90.degree.;
- and .vertline.(a)-(b).vertline..ltoreq.40.degree.;
- wherein retardations of said first and second retardation films are equal and are each less than or equal to 390 nm.
Dependencies are inferred from the claim text.