Liquid crystal panel, liquid crystal display device and terminal device

• US 8,395,731 B2
• Filed: 09/23/2011
• Issued: 03/12/2013
• Est. Priority Date: 03/27/2006
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Uehara, Shinichi, Matsushima, Jin, Sumiyoshi, Ken
• Primary Examiner(s): Kianni, K. Cyrus
• Application Number:
  US13/243,562
• Publication Number:
  US 20120075554A1
• Time in Patent Office: 536 Days
• Field of Search: 349/117, 349/119
• US Class Current: 349/117
• CPC Class Codes: G02F 1/133541 Circular polarisers
• CPC Class Codes: G02F 1/133555 Transflectors
• 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 1/133636 with twisted orientation, e.g. comprising helically oriented LC-molecules or a plurality of twisted birefringent sublayers
• 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 2413/13 Positive birefingence
• CPC Class Codes: G02F 2413/14 Negative birefingence

Abstract

To provide a liquid crystal panel capable of realizing excellent display performance using a circular polarizing plate therein, and a liquid crystal display device and a terminal device using the same, with respect to a semi-transmission type liquid crystal display device in a horizontal electric field mode (In-Plane Switching: IPS).

A viewer-side circular polarizing plate and a backside circular polarizing plate are disposed outside of a viewer-side substrate and a backside substrate respectively, and a viewer-side compensation plate and a backside compensation plate are disposed between the respective polarizing plates and substrates to reduce a refractive index anisotropy of a liquid crystal layer.

Claims

1. A liquid crystal panel comprising a backside substrate, a viewer-side substrate, and a liquid crystal layer in between those two substrates, where a pixel area is configured with a reflective display area in which a light from a viewer-side is reflected, and a transmissive display area in which a light from a backside is transmitted, and where a liquid crystal layer at least in a transmissive display area is driven by a horizontal electric field with an applied voltage parallel to a substrate surface, wherein

the liquid crystal layer is parallel-aligned, and the liquid crystal layer has a refractive index anisotropy in a display surface thereof,

the liquid crystal panel further comprising:

circular polarizing plates individually disposed outside of the backside substrate and the viewer-side substrate respectively; and

a negative A plate of retardation film disposed in at least either one of intervals between the circular polarizing plates and the liquid crystal layer for reducing the refractive index anisotropy of the liquid crystal layer, wherein

a direction of an extraordinary refractive index of the negative A plate is set in a direction in which refractive index anisotropy of the liquid crystal layer under no voltage application is maximum.

2. The liquid crystal panel, as claimed in claim 1, wherein intensity of an electric field for driving the liquid crystal layer is weaker in the reflective display area than in the transmissive display area.

3. The liquid crystal panel, as claimed in claim 1, wherein an interval between electrodes generating a horizontal electric field in the reflective display area is wider than an interval of electrodes generating a horizontal electric field in the transmissive display area.

4. A liquid crystal display device comprising the liquid crystal panel as claimed in claim 1, for a display unit.

5. A terminal device comprising the liquid crystal display device as claimed in claim 4.

6. The terminal device, as claimed in claim 5, is a portable telephone, a personal digital assistant, a game machine, a digital camera, a camcorder, a videoplayer, a laptop computer, a cash dispenser, or a vending machine.