| US 7,450,205 B2 | ||
| Liquid crystal display device with retardation plates | ||
| Hidefumi Yoshida, Kawasaki (Japan); Kenji Okamoto, Kawasaki (Japan); Hideo Chida, Kawasaki (Japan); Kazutaka Hanaoka, Kawasaki (Japan); Seiji Tanuma, Kawasaki (Japan); and Yohei Nakanishi, Kawasaki (Japan) | ||
| Assigned to Sharp Kabushiki Kaisha, Osaka (Japan) | ||
| Filed on Nov. 17, 2003, as Appl. No. 10/714,684. | ||
| Application 10/714684 is a division of application No. 10/079008, filed on Feb. 19, 2002, granted, now 7,151,582. | ||
| Claims priority of application No. 2001-106283 (JP), filed on Apr. 04, 2001. | ||
| Prior Publication US 2004/0095536 A1, May 20, 2004 | ||
| Int. Cl. G02F 1/1335 (2006.01) | ||
| U.S. Cl. 349—119 [349/117; 349/118] | 14 Claims |

| 1. A liquid crystal display device comprising:
a liquid crystal cell comprising a pair of substrates, a liquid crystal layer arranged between the pair of substrates, and
a pair of electrodes for applying a voltage across the liquid crystal layer;
first and second polarizers arranged on either side of the liquid crystal cell;
a first retardation plate arranged between the liquid crystal cell and the first polarizer; and
a second retardation plate arranged between the liquid crystal cell and the second polarizer;
each of the first and second retardation plates having an optical axis in a plane parallel to the surfaces of the substrates,
a retardation in a plane of each of the first and second retardation plates being not less than 120 nm and not more than 160nm,
the optical axis of the first retardation plate being perpendicular to the optical axis of the second retardation plate;
the first and second polarizers having polarizing axes arranged at an angle of 45° with respect to the optical axes of the
first and second retardation plates, and at an angle of 90° with respect to one another;
the liquid crystal layer of the liquid crystal cell being of a vertical alignment type, in which a state of alignments of
liquid crystal molecules changes accompanying a change in a polar angle and a change in an azimuth upon an application of
voltage, and containing a liquid crystal and a resin coexisting with the liquid crystal;
at least one of the pair of electrodes being one of an electrode on which a linear structure of a bent shape is formed and
an electrode having a slit of a bent shape;
a first optical film having a refractive index relationship of nx=ny>nz arranged between the liquid crystal cell and the first
retardation plate;
a second optical film having refractive index relationship of nx=ny<nz arranged between the first retardation plate and the
first polarizer; and
a third optical film arranged between the first retardation plate and the first polarizer or between the second retardation
plate and the second polarizer.
|