| US 7,532,288 B2 | ||
| Liquid crystal display device | ||
| Kazuhiko Ohsawa, Hachioji (Japan); and Tetsushi Yoshida, Tsukui-gun (Japan) | ||
| Assigned to Casio Computer Co., Ltd., Tokyo (Japan) | ||
| Filed on May 21, 2007, as Appl. No. 11/804,950. | ||
| Claims priority of application No. 2007-016655 (JP), filed on Jan. 26, 2007. | ||
| Prior Publication US 2008/0180603 A1, Jul. 31, 2008 | ||
| Int. Cl. G02F 1/1335 (2006.01) | ||
| U.S. Cl. 349—119 [349/117; 349/94] | 20 Claims |

| 1. A liquid crystal display device comprising:
a liquid crystal cell including a pair of substrates in which at least one electrode and an alignment film that covers the
electrode are provided on each of inner surfaces of the substrates facing each other, and a liquid crystal layer that is sandwiched
between the substrates and includes liquid crystal molecules twist-aligned at substantially 90°;
first and second polarizing plates that are arranged on both sides of the liquid crystal cell, each of the polarizing plates
including a polarizing layer having a transmission axis allowing transmission of linear polarized light and an absorption
axis in a direction perpendicular to the transmission axis, and at least one base film that supports the polarizing layer;
and
first and second viewing angle compensating layers that are respectively arranged between the liquid crystal cell and the
first and second polarizing plates, each of the viewing angle compensating layers having a phase difference within a plane
parallel to substrate surfaces of the liquid crystal cell and a phase difference within a plane perpendicular to the substrate
surfaces,
wherein a total value of retardations in a thickness direction, each of which is a product of a phase difference within a
plane perpendicular to the substrate surfaces and a layer thickness, of a plurality of optical layers between the first and
second polarizing layers, including at least the first and second viewing angle compensating layers but excluding the liquid
crystal layer, is set to a value that cancels out a retardation in a liquid crystal layer thickness direction, which is a
product of a phase difference within a plane perpendicular to the substrate surfaces and a liquid crystal layer thickness,
of the liquid crystal layer when a voltage sufficiently high to raise and align the liquid crystal molecules with respect
to the substrate surfaces is applied to the liquid crystal layer between the electrodes of the first and second substrates.
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