LCD DEVICE INCLUDING A REFLECTION FILM HAVING A CONVEX-CONCAVE SURFACE

• US 20080170189A1
• Filed: 01/15/2008
• Published: 07/17/2008
• Est. Priority Date: 01/17/2007
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NEC LCD Technologies Limited (Tianma Microelectronics Company Limited)
• Inventors: SAKAMOTO, Michiaki, NAKA, Kenichirou, MORI, Kenichi, NAGAI, Hiroshi
• Granted Patent: US 7,710,521 B2
• Time in Patent Office: Days
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/136236 using a grey or half tone lithographic process
• CPC Class Codes: G02F 2201/122 having a particular pattern
• CPC Class Codes: G02F 2203/69 Arrangements or methods for testing or calibrating a device
• CPC Class Codes: G03F 1/00 Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
• CPC Class Codes: G03F 1/50 Mask blanks not covered by G03F1/20 - G03F1/34; Preparation thereof
• CPC Class Codes: G03F 7/0007 Filters, e.g. additive colour filters; Components for display devices

Abstract

An LCD device includes a reflective area in each pixel. A reflection film having a convex-concave surface is provided in the reflective area, film in cross section configuration is formed. Each pixel includes a pixel electrode and a common electrode for applying a lateral electric field on a LC layer. The inclination angle of the reflection film has an inclination angle distribution, wherein the angle component in an area corresponding to the electrodes has a lower angle distribution than the angle components in an area corresponding to a gap between adjacent two of the electrodes.

Claims

1. A liquid crystal display (LCD) device comprising:

a reflection area for reflecting incident light and provided in at least a part of a pixel;

a reflection film provided in said reflection area and having a convex-concave surface; and

a plurality of electrodes for driving therebetween liquid crystal (LC) molecules in a lateral direction, wherein;

an inclination angle of said convex-concave surface has different components between a first area overlapping said electrodes and a second area overlapping a gap between adjacent two of said electrodes.

2. The LCD device according to claim 1, wherein components of said inclination angle in said first area have a lower-angle distribution than components of said inclination angle in said second area.

3. The LCD device according to claim 1, wherein said inclination angle of said reflection film is such that light reflected by said second area is emitted toward an observer, and light reflected by said first area is emitted toward a specular reflection direction.

4. The LCD device according to claim 1, wherein components of said inclination angle in said second area are such that components residing in a range of 4.7 to 9.1 degrees are larger in amount than components residing in a range of 0 to 2.9 degrees, and wherein components of said inclination angle in said first area are such that components residing in a range of 0 to 2.9 degrees are larger in amount than components residing in a range of 4.7 to 9.1 degrees.

5. A photomask for use in forming a liquid crystal display (LCD) device including a reflection area for reflecting incident light in at least a part of a pixel;

a reflection film provided in said reflection area and having a convex-concave surface; and

a plurality of electrodes for driving liquid crystal (LC) molecules in a lateral direction, wherein said photomask is used for forming said convex-concave surface on said reflection film, and has no convex-concave pattern in an area overlapping said electrodes.

8. A method of manufacturing a liquid crystal display device operating in a lateral-electric-field drive mode, said method comprising:

coating photosensitive resin on a substrate;

exposing said photosensitive resin by using a photomask according to claim 5;

developing said exposed photosensitive resin;

burning said developed photosensitive resin to form a convex-concave overcoat film; and

forming a reflection film on said convex-concave overcoat film.

6. A photomask for use in forming a liquid crystal display (LCD) device including a reflection area for reflecting incident light in at least a part of a pixel;

a reflection film provided in said reflection area and having a convex-concave surface; and

a plurality of electrodes for driving liquid crystal (LC) molecules in a lateral direction, wherein said photomask is used for forming said convex-concave surface on said reflection film, and includes a light shield pattern added in an area overlapping said electrodes.

9. A method of manufacturing a liquid crystal display device operating in a lateral-electric-field drive mode, said method comprising:

coating photosensitive resin on a substrate;

exposing said photosensitive resin to light by using a photomask according to claim 6;

developing said exposed photosensitive resin;

burning said developed photosensitive resin to form a convex-concave overcoat film; and

forming a reflection film on said convex-concave overcoat film.

7. A photomask for use in forming a liquid crystal display (LCD) device including a reflection area for reflecting incident light in at least a part of a pixel;

a reflection film provided in said reflection area and having a convex-concave surface; and

a plurality of electrodes for driving liquid crystal (LC) molecules in a lateral direction, wherein said photomask is used for forming said convex-concave surface on said reflection film, and includes a gray-tone pattern or a half-tone pattern in an area overlapping said electrodes.

10. A method of manufacturing a liquid crystal display device operating in a lateral-electric-field drive mode, said method comprising:

coating photosensitive resin on a substrate;

exposing said photosensitive resin by using a photomask according to claim 7;

developing said exposed photosensitive resin;

burning said developed photosensitive resin to form a convex-concave overcoat film; and

forming a reflection film on said convex-concave overcoat film.