Semitransparent liquid crystal display element

• US 20050073631A1
• Filed: 11/24/2004
• Published: 04/07/2005
• Est. Priority Date: 02/25/2003
• Status: Active Grant

• Current Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Original Assignee: Toshiba Matsushita Display Technology (Japan Display Incorporated)
• Inventors: Joten, Kazuhiro
• Granted Patent: US 7,081,934 B2
• Time in Patent Office: Days
• US Class Current: 349/99
• CPC Class Codes: G02F 1/1335 Structural association of cells with optical devices, e.g. polarisers or reflectors
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 2203/09 transflective

Abstract

A semitransparent liquid crystal display element comprises a liquid crystal panel composed of a plurality of pixels each having a reflective portion and a transparent portion arranged therein, a first polarizer sheet located on the observer'"'"'s side of the liquid crystal panel, and a second polarizer sheet located on the opposite side of the liquid crystal panel from the first polarizer sheet, the angle of twist of a liquid crystal molecule which forms each pixel of the liquid crystal panel ranging from 44 degrees to 46 degrees. An angle between an absorption axis of the first polarizer sheet and a major axis of a liquid crystal molecule adjacent thereto ranges from 80 degrees to 85 degrees, and an angle between an absorption axis of the second polarizer sheet and a liquid crystal molecule adjacent thereto ranges from 50 degrees to 55 degrees.

Claims

1. A semitransparent liquid crystal display element comprising:

a liquid crystal panel composed of a plurality of pixels each having a reflective portion and a transparent portion arranged therein;

a first polarizer sheet located on the observer'"'"'s side of the liquid crystal panel; and

a second polarizer sheet located on the opposite side of the liquid crystal panel from the first polarizer sheet, the angle of twist of a liquid crystal molecule which forms each pixel of the liquid crystal panel ranging from 44 degrees to 46 degrees, wherein

an angle between an absorption axis of the first polarizer sheet and a major axis of a liquid crystal molecule adjacent thereto ranges from 80 degrees to 85 degrees, and

an angle between an absorption axis of the second polarizer sheet and a liquid crystal molecule adjacent thereto ranges from 50 degrees to 55 degrees.

2. A semitransparent liquid crystal display element according to claim 1, which further comprises a first λ

/2 sheet, located between the liquid crystal panel and the first polarizer sheet, and a first λ

/4 sheet, located between the first λ

/2 sheet and the liquid crystal panel, an angle between a lag axis of the first λ

/2 sheet and a lag axis of the first λ

/4 sheet ranging from 60 degrees to 70 degrees.

3. A semitransparent liquid crystal display element according to claim 1, which further comprises a second λ

/2 sheet, located between the liquid crystal panel and the second polarizer sheet, and a second λ

/4 sheet, located between the second λ

/2 sheet and the liquid crystal panel, an angle between a lag axis of the second λ

/2 sheet and a lag axis of the second λ

/4 sheet ranging from 60 degrees to 70 degrees.

4. A semitransparent liquid crystal display element according to claim 1, wherein a retardation Δ

nd at the reflective portion located in each pixel ranges from 160 nanometers (nm) to 250 nanometers (nm)

5. A semitransparent liquid crystal display element according to claim 1, wherein a retardation Δ

nd at the transparent portion located in each pixel ranges from 280 nanometers (nm) to 350 nanometers (nm).

6. A semitransparent liquid crystal display element according to claim 1, which further comprises a backlight supply unit provided on the opposite side of the second polarizer sheet from the liquid crystal panel in order to supply a backlight to liquid crystal molecules of the liquid crystal panel.