Sharp Kabushiki Kaisha Corporation

Yumi Yoshimura

Hiroshi Ohnishi

Toshiyuki Yoshimizu

Keiko Kishimoto

Kyouhei Isohata

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.

Liquid crystal display apparatus with positive and negative phase plates

In a supertwist type liquid crystal display device using a supertwist type liquid crystal display cell and an optical compensation plate made of phase difference plates of uniaxial oriented polymer film, the phase difference plates include more than two phase difference plates laminated and disposed on one side or both sides of the liquid crystal display cell with various suitable disposition conditions, so that the whiteness level of the display can be improved. In one example, they are placed so that the retardation value of each of the phase difference plates is added and a cross angle between the slow axis of the first phase difference plate and the slow axis of the nth phase difference plate is 20.degree. to 40.degree., and a further cross angle between the slow axis of the first phase difference plate and the rubbing axis of the substrate adjacent to the liquid crystal display cell is in a range from 70.degree. to 90.degree..

Growing community of inventors

Yamatokooriyama, Japan

Yumi Yoshimura