US4068925A
Expired / Lapsed
US
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Liquid crystal display device
Assignee: NEC Corp
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Filing: 1974-12-16
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Granted: 1978-01-17
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Expires: 1994-12-16
Abstract
Abstract A liquid crystal cell includes a nematic liquid crystal of negative dielectric anisotropy is disposed between a pair of transparent electrode substrates. The electrode substrates have on their inner surfaces small grooves formed parallel to each other, the grooves on one surface being perpendicular to those on the other surface. In the absence of a voltage applied between the substrates, the long axes of the liquid crystal molecules are perpendicular to the inner surfaces of the electrode substrates. The addition of a small amount of a cholesteric liquid crystal material markedly improves the contrast of the display.
Inventors
- 👤 Chizuka Tani
- 👤 Fumihiro Ogawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:05
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1337; G02F1/137; G02F1/1335; G02F1/133528; G02F1/133533
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
90 words
A liquid crystal cell including a nematic liquid crystal of negative dielectric anisotropy disposed between a pair of transparent electrode substrates, said electrode substrates having small parallel grooves formed on their inner surfaces, said grooves on one substrate surface being perpendicular to those on the other substrate surface, an active surface agent disposed on the inner surface of at least one substrate for rendering the long axes of the liquid crystal molecules perpendicular to said inner surfaces of said substrates in the absence of a voltage applied between said substrates.
Claim 2
Dependent Claim
90 words
A liquid crystal cell including a nematic liquid crystal of negative dielectric anisotropy disposed between a pair of transparent electrode substrates, said electrode substrates having small parallel grooves formed on their inner surfaces, said grooves on one substrate surface being perpendicular to those on the other substrate surface, an active surface agent disposed on the inner surface of at least one substrate for rendering the long axes of the liquid crystal molecules perpendicular to said inner surfaces of said substrates in the absence of a voltage applied between said substrates.
Claim 3
Dependent Claim
24 words
A liquid crystal cell as claimed in claim 1, wherein a small amount of cholesteric crystal material is included with said nematic liquid crystal.
Claim 4
Dependent Claim
32 words
A combination as in claim 2, wherein said cholesteric material is selected from the group consisting of cholesteryl erucate, cholesteryl nonanoate, cholesteryl benzoate, cholesteryl cinnamate, dicholesteryl phthalate, cholesteryl oleylcarbonate, and cholesteryl chloride.
Claim 5
Dependent Claim
24 words
A combination as in claim 2, wherein said cholesteric crystal material comprises 0.01 to less than 1.0% by weight of said nematic liquid crystal.
Claim 6
Dependent Claim
13 words
A combination as in claim 1, further comprising electrodes included on said substrates.
Claim 7
Dependent Claim
20 words
A combination as in claim 5, further comprising a voltage source connected to said electrodes for selectively energizing said electrodes.
Claim 8
Dependent Claim
19 words
A combination as in claim 1, further comprising two optically polarized plates disposed on opposite sides of said substrates.
Claim 9
Dependent Claim
14 words
A combination as in claim 7, further comprising a screen and a light source.
Claim 10
Dependent Claim
28 words
A combination as in claim 1 wherein said inner surface of each substrate is coated with said active surface agent, and wherein said active surface agent comprises lecithin.
Claim 11
Dependent Claim
105 words
A liquid crystal device comprising: a polarizer for polarizing light entering said device; an analyzer for analyzing light after passage through said device; a first boundary substrate; a second boundary substrate, parallel to and spaced from said first substrate; said first and second substrates each having transparent electrodes on the interior surfaces thereof; a negative dielectric anisotropy, nematic liquid crystal material filling the volume defined by said first and second substrates; and said device being constructed such that said liquid crystal material is characterized by a quasihomeotropic boundary condition in the quiescent state, and a homogeneous twisted nematic bulk molecular arrangement in the active state.
Claim 12
Dependent Claim
105 words
A liquid crystal device comprising: a polarizer for polarizing light entering said device; an analyzer for analyzing light after passage through said device; a first boundary substrate; a second boundary substrate, parallel to and spaced from said first substrate; said first and second substrates each having transparent electrodes on the interior surfaces thereof; a negative dielectric anisotropy, nematic liquid crystal material filling the volume defined by said first and second substrates; and said device being constructed such that said liquid crystal material is characterized by a quasihomeotropic boundary condition in the quiescent state, and a homogeneous twisted nematic bulk molecular arrangement in the active state.
Claim 13
Dependent Claim
26 words
The device as set forth in claim 10 and further comprising: said polarizer and said analyzer are first and second polarizers positioned one adjacent each substrate.
Claim 14
Dependent Claim
18 words
The device as set forth in claim 11 wherein the planes of polarization of said polarizers are orthogonal.
Claim 15
Dependent Claim
23 words
The device as set forth in claim 10 wherein said liquid crystal has a molecular twist of approximately 90° in the active state.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |