Sharp Kabushiki Kaisha Corporation

Keiko Kishimoto

Hiroshi Ohnishi

Toshiyuki Yoshimizu

Yumi Yoshimura

Yumi Baba

An object of the invention is to obtain brighter display in a liquid crystal display apparatus. Light of all the wavelengths in the visible range is converted into circularly polarized light by a first polarization condition converting member, converted into linearly polarized light by a second polarization condition converting member and is modulated by a liquid crystal display device. Then, transmission and block of the light is controlled by a polarizer. Specifically, one of the dextrorotatory circularly polarized light and the levorotatory circularly polarized light is reflected by a spectral member included in the first polarization condition converting member, converted into the other circularly polarized light by a reflecting member included in the first polarization condition converting member and supplied again to the spectral member. The other circularly polarized light is transmitted by the spectral member. Thus, by converting light of all the wavelengths in the visible range into circularly polarized light and then converting the circularly polarized light into linearly polarized light, in principle, 100% of the light is incident on a liquid crystal display device, so that brighter display is achieved.

Liquid crystal display with edge-lit backlight which uses ambient light

It is an object of the invention to provide a liquid crystal display device capable of obtaining a wide viewing angle without coloration caused by a viewing angle. A liquid crystal display cell is disposed between a pair of polarizers, and between the liquid crystal display cell and the pair of polarizers, first optical compensation plates are disposed at the side of the liquid crystal display cell, and second optical compensation plates are disposed at the side of the polarizer. The first optical compensation plates have a refractive index anisotropy in the plane, and the refractive index thereof in the thickness direction is nearly equal to the refractive index of a minimum value in the plane, whereas the second optical compensation plates have no refractive index anisotropy in the plane, the refractive index in the thickness direction is greater than the refractive index in the plane, and a positive phase difference is expressed by inclination from the normal direction. By the optical compensation plates, the coloration of the display in the display plane of the liquid crystal display device and in the viewing angle direction inclined in a direction parallel to the display plane from the normal direction of the display plane can be compensated, so that a wide viewing angle of a high contrast is obtained.

Liquid crystal display device having compensator with particular

A liquid crystal display device of stable color tone uses phase difference plates made of a uniaxially stretched polymer film and comprises a polarizer plate, a first phase difference plate, a second phase difference plate, a supertwisted nematic type liquid crystal display panel, and a polarizer plate which are stacked on each other in this order. The rate of retardation change with the change in viewing angle of the uniaxially stretched polymer film is denoted coefficient K defined by three-dimensional refractive indexes, coefficient K1 of one of the phase difference plates is set in a range of -1.ltoreq.K1.ltoreq.0.17 and coefficient K2 of the other phase difference plate is set in a range of 0.ltoreq.K2.ltoreq.1.

Liquid crystal display device with compensators

A liquid crystal display is disclosed. The liquid crystal display includes: a liquid crystal panel including a pair of substrates and super twisted nematic liquid crystal having a twisted structure with a twist angle of 180.degree. or more, the super twisted nematic liquid crystal being contained between the pair of substrates; a pair of polarizing plates which sandwich the liquid crystal panel; an optically anisotropic plate having a twisted structure with a twist angle of 90.degree. or less, the optically anisotropic plate being disposed between one of the pair of polarizing plates and the liquid crystal panel, or between the other one of the pair of polarizing plates and the liquid crystal panel; and a phase plate of a polymeric film which is uniaxially extended, the phase plate being disposed between one of the pair of polarizing plates and the liquid crystal panel, or between the other one of the pair of polarizing plates and the liquid crystal panel.

Liquid crystal display with optically anisotropic member having a

In a liquid crystal display device using uniaxially drawn polymer film as a phase difference plate, as the elevation angle becomes wider, the difference between the retardation of the phase difference plate and the retardation of the liquid crystal display panel becomes larger, and the optical compensation relation is broken, and the viewing angle becomes narrower. To solve this problem, uniaxially drawn polymer films are prepared separately from polycarbonate and polystyrene which differ in the optical properties, and they are disposed as the optical compensation plate at the front side and back side of a liquid crystal cell, or they are laminated and disposed at the front side and back side of a liquid crystal cell.

Liquid crystal display device with positive and negative compensating

In a supertwist type liquid crystal display, a pair of upper and lower polarizers and polymer films are disposed in such an arrangement that the upper polarizer, first uniaxial oriented polymer film, second uniaxial oriented polymer film, supertwist type liquid crystal cell, third uniaxial oriented polymer film, first biaxial oriented polymer film and the lower polarizer are sequentially piled on in this order, and each of said first, second and third uniaxial oriented polymer films has a positive optical anisotropy and said first biaxial oriented polymer film has a negative optical anisotropy.

Liquid crystal display having positive and negative uniaxially oriented

A liquid crystal display apparatus includes a twist supertwisted nematic liquid crystal panel (1) including a liquid crystal layer (8) provided between first and second transparent substrates (2, 3), and a first phase plate group (11; 13, 14) including at least one uniaxially stretched polymer film arranged on the outer surface of the first substrate (2). The apparatus further includes a first polarizing plate (9) arranged on the first phase plate group (11; 13, 14) and a second phase plate group (12; 15, 16) including at least one uniaxially stretched polymer film arranged on the outer surface of the second substrate (3) and. Finally, the apparatus includes a second polarizing plate (10) arranged on the second phase plate group (12; 15, 16), wherein at least one of the uniaxially stretched polymer films (11, 12; 13, 14, 15, 16) has positive optical anisotropy and the others have negative optical anisotropy.

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Osaka, Japan

Keiko Kishimoto