EP0576931A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Liquid crystal display device
Assignee: Casio Computer Co Ltd
•
Filing: 1993-06-17
•
Granted: —
•
Expires: 2013-06-17
Abstract
Abstract A polarizer (2) is arranged on the incident side of a TN type liquid crystal cell (1) in which the arrangement of liquid crystal molecules is twist-aligned through substantially 90° in a direction from one substrate (8) to the opposite substrate (11) and the value of a product Δn c ·d c of a refractive index anisotropy Δn c and a gap d c is set within a range of 300 to 600 nm, and an analyzer (3) is arranged on the exit side of the liquid crystal cell. A twist-aligned retardation plate (4), in which the arrangement of polymer molecules is twist-aligned through 90° in a direction opposite to the twist direction of the twist orientation of the liquid crystal molecules and the value of Δn·d ranges between 100 and 600 nm, is arranged between the liquid crystal cell and the analyzer.
Inventors
- 👤 Takashi c/o Hamura R & D Center Miyashita
- 👤 Yoshinaga c/o Hamura R & D Center Miyazawa
- 👤 Zenta C/O Hamura R & D Center Kikuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 02:32
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; G02F1/133636; G02F1/137; G02F1/139; G02F1/1396
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
161 words
A liquid crystal display device characterized by comprising: a pair of substrates (8, 11, 24, 27) having surfaces which oppose each other and on which electrodes (5, 9, 22, 25) crossing each other and orientation films (7, 10, 23, 26) covering said electrodes and having undergone orientation processing in predetermined directions are formed; a nematic liquid crystal layer (13, 29) which is present between said orientation films and in which the arrangement of liquid crystal molecules is twist-aligned within a predetermined range of angles in a direction from one substrate to the other; a pair of polarizing plates (2, 3, 30, 32) arranged outside said pair of substrates to sandwich said substrates; and at least one twist-aligned retardation plate (4, 14, 15, 16, 17, 19, 30, 33) which is arranged between said pair of polarizing plates and in which the arrangement of polymer molecules is twist-aligned over a predetermined range of angles in a direction from one surface to the other.
Claim 2
Dependent Claim
59 words
A liquid crystal display device according to claim 1, characterized in that said nematic liquid crystal layer has the arrangement of the molecules, a twist angle of which is 80° to 100°, and a refractive index anisotropy Δn c and a layer thickness d c , a product Δn c ·d c of which is 300 to 600 nm.
Claim 3
Dependent Claim
35 words
A liquid crystal display device according to claim 1 or 2, characterized in that a product Δn·d of a refractive index anisotropy Δn and a plate thickness d of said twist-aligned retardation plate is positive.
Claim 4
Dependent Claim
47 words
A liquid crystal display device according to claim 1, 2, or 3, characterized in that the polymer molecules constituting said twist-aligned retardation plate are arranged parallel to each surface and the arrangement of the polymer molecules is twist-aligned in a direction from one surface to the other.
Claim 5
Dependent Claim
55 words
A liquid crystal display device according to any one of claims 1 to 4, characterized in that one of said twist-aligned retardation plate is arranged, and the arrangement of molecules of said twist-aligned retardation plate is twist-aligned through 80° to 120° in a direction opposite to the twist direction of said nematic liquid crystal layer.
Claim 6
Dependent Claim
90 words
A liquid crystal display device according to any one of claims 1 to 4, characterized in that two of said twist-aligned retardation plates are arranged, the arrangement of molecules of one of said twist-aligned retardation plates is twist-aligned through 80° to 120° in a direction opposite to the twist direction of said nematic liquid crystal layer, and the arrangement of molecules of the other one of said twist-aligned retardation plates is twist-aligned through 80° to 120° in the same direction as the twist direction of said nematic liquid crystal layer.
Claim 7
Dependent Claim
37 words
A liquid crystal display device according to claim 1 or 2, characterized in that said twist-aligned retardation plate has a refractive index anisotropy Δn and a plate thickness d , a product Δn·d of which is negative.
Claim 8
Dependent Claim
100 words
A liquid crystal display device according to claim 1, 2, or 7, characterized in that the polymer molecules constituting said twist-aligned retardation plate are arranged parallel to one surface and the arrangement of the polymer molecules is twist-aligned in a direction from one surface to the other, and in said twist-aligned retardation plate, a product ΔN·d of an effective refractive index anisotropy ΔN given by: ΔN = n o - √ {(n e ² + n o ²)/2 ¯ } and a plate thickness d is -30 to -600 nm, and the molecules are twisted not less than five turns.
Claim 9
Dependent Claim
65 words
A liquid crystal display device according to claim 1, 2, or 7, characterized in that the polymer molecules constituting said twist-aligned retardation plate are tilted with respect to the surface of said plate and the arrangement of the polymer molecules is twist-aligned in a direction from one surface to the other, and the product Δn·d of said twist-aligned retardation plate is -300 to -600 nm.
Claim 10
Dependent Claim
59 words
A liquid crystal display device according to claim 1, characterized in that said nematic liquid crystal layer has the arrangement of the molecules, a twist angle of which is 220° to 260° and a refractive index anisotropy Δn c and a layer thickness d c , a product Δn c ·d c of which is 700 to 800 nm.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.