US4783148A
Expired / Lapsed
US
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Ferroelectric liquid crystal device
Assignee: Canon Inc
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Filing: 1987-09-18
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Granted: 1988-11-08
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Expires: 2007-09-18
Abstract
Abstract A ferroelectric liquid crystal device is by disposing between a pair of substrates a ferroelectric liquid crystal composition showing a phase transition series of isotropic→chiral nematic phase (N * )→chiral smectic C phase on temperature decrease. The alignment state of the liquid crystal is improved by forming alignment control films of mutually different materials on the pair of substrates. The alignment state is improved especially when the liquid crystal composition is formulated to show a helical pitch in N * phase which exceeds three times the spacing between the pair of substrates.
Inventors
- 👤 Akira Tsuboyama
- 👤 Toshiharu Uchimi
- 👤 Kenji Shinjo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:23
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/42; C09K19/46; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1337; G02F1/133711; G02F1/137; G02F1/139; G02F1/141
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
66 words
A ferroelectric liquid crystal device, comprising a pair of substrates, and a ferroelectric liquid crystal composition sandwiched between the substrates and showing a phase transition from isotropic phase through chiral nematic phase to chiral smectic C phase in the course of temperature decrease; the pair of substrates having, on the surfaces thereof contacting the ferroelectric liquid crystal composition, alignment control films which comprise mutually different materials.
Claim 2
Dependent Claim
66 words
A ferroelectric liquid crystal device, comprising a pair of substrates, and a ferroelectric liquid crystal composition sandwiched between the substrates and showing a phase transition from isotropic phase through chiral nematic phase to chiral smectic C phase in the course of temperature decrease; the pair of substrates having, on the surfaces thereof contacting the ferroelectric liquid crystal composition, alignment control films which comprise mutually different materials.
Claim 3
Dependent Claim
23 words
A device according to claim 1, wherein at least one of the alignment control films has been subjected to a uniaxial orientation treatment.
Claim 4
Dependent Claim
13 words
A device according to claim 2, wherein said uniaxial orientation treatment is rubbing.
Claim 5
Dependent Claim
24 words
A device according to claim 1, wherein said ferroelectric liquid crystal shows at least two stable states in the absence of an electric field.
Claim 6
Dependent Claim
39 words
A device according to claim 1, wherein said liquid crystal composition provides a helical pitch (p) in the chiral nematic phase and the pair of substrates are disposed to have a spacing (d) therebetween satisfying the relation of p/d≧3.
Claim 7
Dependent Claim
39 words
A device according to claim 1, wherein at least one of the alignment control films comprises a film of a resin selected from the group consisting of polyimide, a silane coupling agent, polyvinyl alcohol, polyethylene, polyamide, and cellulose resin.
Claim 8
Dependent Claim
23 words
A device according to claim 1, wherein one of the alignment control films comprises polyimide and the other comprises a silane coupling agent.
Claim 9
Dependent Claim
24 words
A device according to claim 1, wherein one of the alignment control films comprises polyvinyl alcohol and the other comprises a silane coupling agent.
Claim 10
Dependent Claim
20 words
A device according to claim 1, wherein one of the alignment control films comprises polyimide and the other comprises polyethylene.
Claim 11
Dependent Claim
22 words
A device according to claim 1, wherein one of the alignment control films comprises polyvinyl alcohol and the other comprises polyvinyl alcohol.
Claim 12
Dependent Claim
21 words
A device according to claim 1, wherein one of the alignment control films comprises polyamide and the other comprises cellulose resin.
References Cited (Backward Citations)
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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) | 1991-11-08 | 1992-05-09 | 1992-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-08 | 1996-05-09 | 1996-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-08 | 2000-05-09 | 2000-11-08 | $7700.00 | Window Closed / Lapsed |