Liquid crystal display device and electronic apparatus

• US 20050190328A1
• Filed: 02/25/2005
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Sekime, Tomoaki
• Granted Patent: US 7,583,343 B2
• Time in Patent Office: Days
• US Class Current: 349/119
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133632 with refractive index ellipsoid inclined relative to the LC-layer surface
• CPC Class Codes: G02F 1/133634 the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
• CPC Class Codes: G02F 1/1365 in which the switching element is a two-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/1398 the twist being below 90°
• CPC Class Codes: G02F 2413/105 with varying inclination in thickness direction, e.g. hybrid oriented discotic LC

Abstract

The liquid crystal display device includes a liquid crystal cell having a nematic liquid crystal layer, upper and lower retardation plates sandwiching the liquid crystal cell, an upper polarizer above the upper retardation plate, and a lower polarizer below the lower retardation plate. The nematic liquid crystal layer is arranged at the upper and lower substrates with the twist angle set in a range of 0° to 70° which is subjected to a rubbing process at a predetermined angle relative to a reference direction. The lower retardation plate has a first lower retardation plate of a discotic liquid crystal film with hybrid alignment, and a second lower retardation plate of a polymer film having a three-dimensional refractive index anisotropy. The three-dimensional refractive index of the second lower retardation plate is set in a range of −0.7 to 0.7.

Claims

1. A liquid crystal display device comprising:

a lower polarizer;

a lower retardation plate formed above the lower polarizer, the lower retardation plate having a first lower retardation plate made of a discotic liquid crystal film with hybrid alignment and a second lower retardation plate made of a polymer film having a three-dimensional refractive index anisotropy, the second lower retardation plate being disposed below the first lower retardation plate and having a three-dimensional refractive index in a range of −

0.7 to 0.7;

a liquid crystal cell formed above the lower retardation plate, the liquid crystal cell having a nematic liquid crystal layer, the nematic liquid crystal layer having a twist angle set in a range of 0°

to 70°

;

an upper retardation plate formed above the liquid crystal cell; and

an upper polarizer formed above the upper retardation plate.

2. The liquid crystal display device according to claim 1, wherein the first lower retardation plate has a hybrid alignment axis in a range of 85°

to 95°

in a counterclockwise direction with respect to a reference direction when the first lower retardation plate is seen from the top.

3. The liquid crystal display device according to claim 2, wherein the second lower retardation plate has a phase retardation axis in a range of 85°

to 95°

in a counterclockwise direction with respect to the reference direction when the second lower retardation plate is seen from the top.

4. The liquid crystal display device according claim 1, wherein the upper retardation plate has first and second upper retardation plates whose phase retardation axes are different in their direction from each other as seen from the top and which are made of a low dispersion film.

5. The liquid crystal display device according to claim 1, wherein the upper retardation plate is a single retardation plate made of a reverse wavelength dispersion film.

6. The liquid crystal display device according to claim 1, wherein the upper retardation plate has a first upper retardation plate made of a discotic liquid crystal film with hybrid alignment, and a second upper retardation plate made of a polymer film having a three-dimensional refractive index anisotropy, and the second upper retardation plate is disposed above the first upper retardation plate.

7. The liquid crystal display device according to claim 1, wherein the liquid crystal cell is a transflective liquid crystal cell having a partially reflecting layer, and the thickness of the nematic liquid crystal layer in a reflecting portion corresponding to the partially reflecting layer is smaller than that of the nematic liquid crystal layer in a transmitting portion other than the reflecting portion.

8. An electronic apparatus comprising the liquid crystal display device according to claim 1.