US4405209A
Expired / Lapsed
US
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Matrix liquid-crystal display devices
Assignee: Sharp Corp
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Filing: 1981-02-10
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Granted: 1983-09-20
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Expires: 2001-02-10
Abstract
Abstract There discloses a matrix liquid-crystal display device which is effective for the display of images particularly in a TV set and in which the liquid-crystal layer contains a dopant in a specific range of quantity which is far greater than a quantity of dopant employed in any known device.
Inventors
- 👤 Fumiaki Funada
- 👤 Toshiaki Takamatsu
- 👤 Ishii Yutaka
- 👤 Tomio Wada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:40
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/13743; G02F1/1375; C; C09; C09K; C09K19/00; C09K19/52; C09K19/58; C09K19/582
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
213 words
A matrix liquid-crystal display device for video image using DTN mode comprising a pair of transparent substrates defining a pair of mutually facing surfaces, transparent electrodes provided on each of said surfaces, an insulating layer with orienting property formed on said electrodes on each of said surfaces, a liquid-crystal layer formed by depolarization in a twisted-nematic layer, said liquid crystal being nematic with a negative dielectric anisotropy, and sandwiched between said mutually facing insulating layers, and a polarizer provided on the opposite surface of each of said substrates from said liquid-crystal layer, and the liquid-crystal layer contains an ionic dopant such that the cut-off frequency Fc(Hz) of said liquid-crystal layer satisfies the following relationship within a range of ambient temperatures: ##EQU11## in which N stands for the number of multiplex driving, F stands for the frame frequency of an image signal, C stands for the capacitance per unit area of said insulating layers, and C o stands for the capacitance per unit area of said insulating layers when they have a specific dielectric constant ε of about 4 and a thickness of about 100 A, where the f c value of the device is at least about 29 kHz, and such that the reproduction of a video image with a half-tone is achieved.
Claim 2
Dependent Claim
213 words
A matrix liquid-crystal display device for video image using DTN mode comprising a pair of transparent substrates defining a pair of mutually facing surfaces, transparent electrodes provided on each of said surfaces, an insulating layer with orienting property formed on said electrodes on each of said surfaces, a liquid-crystal layer formed by depolarization in a twisted-nematic layer, said liquid crystal being nematic with a negative dielectric anisotropy, and sandwiched between said mutually facing insulating layers, and a polarizer provided on the opposite surface of each of said substrates from said liquid-crystal layer, and the liquid-crystal layer contains an ionic dopant such that the cut-off frequency Fc(Hz) of said liquid-crystal layer satisfies the following relationship within a range of ambient temperatures: ##EQU11## in which N stands for the number of multiplex driving, F stands for the frame frequency of an image signal, C stands for the capacitance per unit area of said insulating layers, and C o stands for the capacitance per unit area of said insulating layers when they have a specific dielectric constant ε of about 4 and a thickness of about 100 A, where the f c value of the device is at least about 29 kHz, and such that the reproduction of a video image with a half-tone is achieved.
Claim 3
Dependent Claim
43 words
A device as set forth in claim 1, wherein said frame frequency F is 60 Hz, so that said device may be used for the display of a TV picture by commercial TV broadcasting at a frame frequency F TV of 30 Hz.
Claim 4
Dependent Claim
84 words
A device as set forth in claim 2, wherein said insulating layers have a thickness of about 100 A and a specific dielectric constant ε of about 4, said frame frequency F is 60 Hz, and said liquid-crystal layer contains said dopant to the extent that said cut-off frequency f c satisfies the following relationship: 960N≧f.sub.c ≧480N so that said device may be used for the display of a TV picture by commercial TV broadcasting at a frame frequency F TV of 30 Hz.
Claim 5
Dependent Claim
19 words
A device as set forth in claim 3, wherein said liquid-crystal composition is composed of Schiff's base liquid-crystal materials.
Claim 6
Dependent Claim
19 words
A device as set forth in claim 1, 3, or 4, wherein said dopant comprises a quaternary ammonium compound.
Claim 7
Dependent Claim
15 words
A device as set forth in claim 1 or 5, wherein said dopant comprises tetrabutylammonium-3,5-dinitrobenzoate.
Claim 8
Dependent Claim
17 words
A device as set forth in claim 3, wherein said liquid-crystal layer has a thickness of 7μ±1μ.
Claim 9
Dependent Claim
23 words
A device as set forth in claim 1, wherein f c is in the range of from about 29 to about 58 kHz.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-19 | 1987-03-21 | 1987-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-19 | 1991-03-21 | 1991-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-19 | 1995-03-21 | 1995-09-20 | $7700.00 | Window Closed / Lapsed |