LCD device including a reflection film having a convex-concave surface

• US 8,284,356 B2
• Filed: 03/16/2010
• Issued: 10/09/2012
• Est. Priority Date: 01/17/2007
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Inventors: Naka, Kenichirou, Sakamoto, Michiaki, Nagai, Hiroshi, Mori, Kenichi
• Primary Examiner(s): ROJAS, OMAR R
• Application Number:
  US12/724,902
• Publication Number:
  US 20100173231A1
• Time in Patent Office: 938 Days
• Field of Search: None
• 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 photomask used for forming a convex-concave surface on a reflective area of liquid crystal display (LCD) device including comb teeth electrodes for driving liquid crystal (LC) molecules in a lateral-electric-field drive mode, the reflective area in at least a part of a pixel, wherein said photomask comprises:

a first area corresponding to, in said reflective area, an area under each of said comb teeth electrodes, and

a second area corresponding to, in said reflective area, and area between adjacent electrodes of said comb teeth electrodes, said second area being present between adjacent portions of said first area,

wherein said second area has a predetermined pattern formed by at least one light transmitting area and at least on light absorbing area absorbing more light than said at least one light transmitting area, and said first area has a uniform light transmitting property is used for forming said convex-concave surface on said reflection film, and has no convex-concave pattern in an area overlapping said electrodes,

wherein said first area comprises a half-tone mask.

2. A photomask used for forming a convex-concave surface on a reflective area of liquid crystal display (LCD) device including comb teeth electrodes for driving liquid crystal (LC) molecules in a lateral-electric-field drive mode, the reflective area in at least a part of a pixel, wherein said photomask comprises:

a first area corresponding to, in said reflective area, an area under each of said comb teeth electrodes, and

a second area corresponding to, in said reflective area, and area between adjacent electrodes of said comb teeth electrodes, said second area being present between adjacent portions of said first area,

wherein said second area has a predetermined pattern formed by at least one light transmitting area and at least on light absorbing area absorbing more light than said at least one light transmitting area, and said first area has a uniform light transmitting property is used for forming said convex-concave surface on said reflection film, and has no convex-concave pattern in an area overlapping said electrodes,

wherein each of said at least one light transmitting area of said second area has a triangular shape.

3. A photomask used for forming a convex-concave surface on a reflective area of a liquid crystal display (LCD) device including comb teeth electrodes for driving liquid crystal (LC) molecules in a lateral-electric-field drive mode, the reflective area in at least a part of a pixel, wherein said photomask comprises:

a first area corresponding to, in said reflective area, an area under each of said comb teeth electrodes, and

a second area corresponding to, in said reflective area, an area between adjacent electrodes of said comb teeth electrodes, said second area being present between adjacent portions of said first area,

wherein said second area comprises a light absorbing area and a light transmitting area, wherein said light absorbing area comprises a plurality of dots arranged in said light transmitting area, said light absorbing area absorbing more light than said light transmitting area, and

wherein said first area comprises a grey-tone area and a light transmitting area, wherein said grey-tone area comprises a plurality of dots arranged in said light transmitting area, wherein said plurality of dots of said grey-tone area are smaller than said plurality of dots of said light absorbing area.