EP0341702A2
Expired / Lapsed
EP
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Liquid-crystal display apparatus
Assignee: Toshiba Corp
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Filing: 1989-05-10
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Granted: —
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Expires: 2009-05-10
Abstract
Abstract A liquid-crystal display apparatus comprising two substrates (1, 2) opposing each other and having electrodes (3, 4) formed on the opposing surfaces (1a, 2a), at least one of the electrodes (3, 4) being transparent, a nematic liquid crystal layer (8) interposed between the substrates (1, 2) and having pre-tilt angle ϑ of greater than 1° with respect to the surfaces (1a, 2a) of the substrates (1, 2), and having a twisting angle of 180 to 360° from the first substrate (1) to the second substrate (2), a first polarizer (9) arranged on that side of the first substrate (1) which faces away from the electrode (3) formed thereon, a second polarizer (11) arranged on that side of the second substrate (2) which faces away from the electrode (4) formed thereon, and an optical retardation member (10) or a combination of an optical retardation member (10a) and a quarter-wave plate (10b), each located between the polarizers (9, 11). The value of R = Δn·d·cos⁺ϑ ranges from 0.4 to 0.8, where Δn is the optical anisotropy of the nematic liquid crystal material (8), d (µm) is the thickness of the liquid crystal layer (8), and ϑ is the pre-tilt angle of the liquid crystal material (8). The value of R′ = Δn′·d′ ranges from 0.22+0.55m to 0.42+0.65m, or from 0.47+0.55m to 0.67+0.65m (m = 0, 1, or 2), where Δn′ is the optical anisotropy of the optical retardation member (10) and d′ (µm) is the thickness of the optical retardation member (10). Owing to the optical retardation member (10) located between the polarizers (9, 11), and also to the specific values of R and R′, the apparatus can perform high-quality monochrome display with great background whiteness and high image contrast.
Inventors
- 👤 Kazuo C/O Intellectual Property Division Kawasaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 21:43
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/13363; G02F1/137; G02F1/139; G02F1/1396; G02F1/1397; G02F1/133638; G02F2413/00; G02F2413/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
224 words
A liquid-crystal display apparatus comprising: first and second substrates opposing each other and having electrodes formed on the opposing surfaces, at least one of the electrodes being transparent; a nematic liquid crystal layer interposed between said first and second substrates and having pre-tilt angle ϑ of greater than 1° with respect to the surfaces of said first and second substrates, and having a twisting angle of 180 to 360° from said first substrate to said second substrate; a first polarizer arranged on that side of said first substrate which faces away from the electrode formed thereon; a second polarizer arranged on that side of said second substrate which faces away from the electrode formed thereon; and an optical retardation member located between said first and second polarizers, characterized in that the value of R = Δn·d·cos²ϑ ranges from 0.4 to 0.8, where Δn is the optical anisotropy of said nematic liquid crystal material (8), d (µm) is the thickness of said liquid crystal layer (8), and ϑ is the pre-tilt angle of said liquid crystal material (8), and the value of R′ = Δn′·d′ ranges from 0.22+0.55m to 0.42+0.65m, or from 0.47+0.55m to 0.67+0.65m (m = 0, 1, or 2), where Δn′ is the optical anisotropy of said optical retardation member (10) and d′ (µm) is the thickness of said optical retardation member (10).
Claim 2
Dependent Claim
224 words
A liquid-crystal display apparatus comprising: first and second substrates opposing each other and having electrodes formed on the opposing surfaces, at least one of the electrodes being transparent; a nematic liquid crystal layer interposed between said first and second substrates and having pre-tilt angle ϑ of greater than 1° with respect to the surfaces of said first and second substrates, and having a twisting angle of 180 to 360° from said first substrate to said second substrate; a first polarizer arranged on that side of said first substrate which faces away from the electrode formed thereon; a second polarizer arranged on that side of said second substrate which faces away from the electrode formed thereon; and an optical retardation member located between said first and second polarizers, characterized in that the value of R = Δn·d·cos²ϑ ranges from 0.4 to 0.8, where Δn is the optical anisotropy of said nematic liquid crystal material (8), d (µm) is the thickness of said liquid crystal layer (8), and ϑ is the pre-tilt angle of said liquid crystal material (8), and the value of R′ = Δn′·d′ ranges from 0.22+0.55m to 0.42+0.65m, or from 0.47+0.55m to 0.67+0.65m (m = 0, 1, or 2), where Δn′ is the optical anisotropy of said optical retardation member (10) and d′ (µm) is the thickness of said optical retardation member (10).
Claim 3
Dependent Claim
22 words
An apparatus according to claim 1, characterized in that said optical retardation member (10) performs the function of an optical retardation plate.
Claim 4
Dependent Claim
19 words
An apparatus according to claim 1, characterized in that said optical retardation member (10) is an optical retardation plate.
Claim 5
Dependent Claim
25 words
An apparatus according to claim 1, characterized in that said optical retardation member (10) comprises an optical retardation plate (10a) and a half-wave plate (10b).
Claim 6
Dependent Claim
37 words
An apparatus according to claim 1, characterized in that said optical retardation member (10) is arranged either between said first electrodes (3) and said first polarizer, or between said second electrodes (4) and said second polarizer (11).
Claim 7
Dependent Claim
15 words
An apparatus according to claim 1, characterized in that R ranges from 0.6 to 0.8.
Claim 8
Dependent Claim
20 words
An apparatus according to claim 1, characterized in that R′ ranges from 0.22 to 0.42, or from 0.47 to 0.67.
Claim 9
Dependent Claim
23 words
An apparatus according to claim 1, characterized in that the twist angle of said nematic liquid crystal (8) ranges from 210 to 270°.
Claim 10
Dependent Claim
229 words
A liquid-crystal display apparatus comprising: first and second substrates opposing each other and having electrodes formed on the opposing surfaces, at least one of the electrodes being transparent; a nematic liquid crystal layer interposed between said first and second substrates and having pre-tilt angle ϑ of greater than 1°, with respect to the surfaces of said first and second substrates, and having a twisting angle of 180 to 360° from said first substrate to said second substrate; a first polarizer arranged on that side of said first substrate which faces away from the electrode formed thereon; a second polarizer arranged on that side of said second substrate which faces away from the electrode formed thereon; and an optical retardation member and a quarter-wave plate, each located between said first and second polarizers, characterized in that the value of R = Δn·d·cos²ϑ ranges from 0.4 to 0.8, where Δn is the optical anisotropy of said nematic liquid crystal material (8), d (µm) is the thickness of said liquid crystal layer (8), and ϑ is the pre-tilt angle of said liquid crystal material (8), and the value of R′ = Δn′·d′ ranges from 0.22+0.55m to 0.42+0.65m, or from 0.47+0.55m to 0.67+0.65m (m = 0, 1, or 2), where Δn′ is the optical anisotropy of said optical retardation member (10) and d′ (µm) is the thickness of said optical retardation member (10).
Claim 11
Dependent Claim
229 words
A liquid-crystal display apparatus comprising: first and second substrates opposing each other and having electrodes formed on the opposing surfaces, at least one of the electrodes being transparent; a nematic liquid crystal layer interposed between said first and second substrates and having pre-tilt angle ϑ of greater than 1°, with respect to the surfaces of said first and second substrates, and having a twisting angle of 180 to 360° from said first substrate to said second substrate; a first polarizer arranged on that side of said first substrate which faces away from the electrode formed thereon; a second polarizer arranged on that side of said second substrate which faces away from the electrode formed thereon; and an optical retardation member and a quarter-wave plate, each located between said first and second polarizers, characterized in that the value of R = Δn·d·cos²ϑ ranges from 0.4 to 0.8, where Δn is the optical anisotropy of said nematic liquid crystal material (8), d (µm) is the thickness of said liquid crystal layer (8), and ϑ is the pre-tilt angle of said liquid crystal material (8), and the value of R′ = Δn′·d′ ranges from 0.22+0.55m to 0.42+0.65m, or from 0.47+0.55m to 0.67+0.65m (m = 0, 1, or 2), where Δn′ is the optical anisotropy of said optical retardation member (10) and d′ (µm) is the thickness of said optical retardation member (10).
Claim 12
Dependent Claim
22 words
An apparatus according to claim 9, characterized in that said optical retardation member (10) performs the function of an optical retardation plate.
Claim 13
Dependent Claim
19 words
An apparatus according to claim 9, characterized in that said optical retardation member (10) is an optical retardation plate.
Claim 14
Dependent Claim
37 words
An apparatus according to claim 9, characterized in that said optical retardation member (10) is arranged either between said first electrodes (3) and said first polarizer (9), or between said second electrodes (4) and said second polarizer.
Claim 15
Dependent Claim
15 words
An apparatus according to claim 9, characterized in that R ranges from 0.6 to 0.8.
Claim 16
Dependent Claim
20 words
An apparatus according to claim 9, characterized in that R′ ranges from 0.22 to 0.42, or from 0.47 to 0.67.
Claim 17
Dependent Claim
23 words
An apparatus according to claim 9, characterized in that the twist angle of said nematic liquid crystal (8) ranges from 210 to 270.
References Cited (Backward Citations)
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