| US 7,515,214 B2 | ||
| Liquid crystal display comprising a pixel region including areas with different effective voltages | ||
| Kazuya Ueda, Kawasaki (Japan); Tsuyoshi Kamada, Kawasaki (Japan); Hidefumi Yoshida, Kawasaki (Japan); Yoshio Koike, Kawasaki (Japan); and Kenji Okamoto, Kawasaki (Japan) | ||
| Assigned to Sharp Kabushiki Kaisha, Osaka (Japan) | ||
| Filed on Mar. 24, 2004, as Appl. No. 10/808,218. | ||
| Claims priority of application No. 2003-093191 (JP), filed on Mar. 31, 2003. | ||
| Prior Publication US 2005/0128371 A1, Jun. 16, 2005 | ||
| Int. Cl. G02F 1/133 (2006.01); G02F 1/1335 (2006.01); G02F 1/1343 (2006.01); G02F 1/1337 (2006.01) | ||
| U.S. Cl. 349—33 [349/106; 349/143; 349/129] | 18 Claims |
| 1. A liquid crystal display comprising:
a pair of substrates provided opposite to each other with one of said substrates having a pixel electrode and the other of
said substrates having a common electrode;
a liquid crystal sealed between the pair of substrates; and
a pixel region including at least one low effective voltage area in which an effective voltage applied by the pixel and the
common electrodes to the liquid crystal is lower than a voltage applied between the pixel and the common electrodes at another
area, the at least one low effective voltage area occupying part of the region in a predetermined area ratio, the pixel region
having a threshold voltage that is different between the at least one low effective voltage area and said another area, and
the pixel region also including a color filter layer having one color formed on at least one of the pair of substrates, wherein
the effective voltage in the pixel region is different from that in another pixel region including a color filter layer having
another color, wherein at least one of the color filters is blue, and further wherein the effective voltage in the low effective
voltage areas associated with the blue color filter is lower than the effective voltage in the low effective voltage areas
associated with color filters of colors other than blue,
wherein the low effective voltage area has an effective voltage decreasing slit, formed on at least one of the electrodes,
wherein the liquid crystal is a nematic liquid crystal having negative dielectric constant anisotropy whose initial alignment
is vertical to a surface of the substrates when no voltage is applied between the pixel and common electrodes,
wherein:
the plurality of color filter layers have center transmission wavelengths λk (k=1, 2, . . . , N; N>2);
a cell thickness d of the pixel region is substantially constant regardless of the center transmission wavelengths λk;
effective retardation Δn(λk, θk) of the liquid crystal layer at the time of application of a data voltage Vk that imparts
a tilt angle θk to liquid crystal molecules satisfies a relationship expressed by:
|Δn(λi, θi)·d/λi−Δn(λj, θj)·d/λj|<0.2
(i, j=1, 2, . . . , N; i≠j) between pixel regions each having two kinds among the color filter layers; and
chromaticity (x0, y0) of an incident light source which has been transmitted or reflected by the liquid crystal display panel and chromaticity
(x1, y1) of display of white satisfy a relationship expressed by:
((x0−x1)2+(y0−y1)2)1/2<0.1
when no polarizer is provided.
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