US5099344A
Expired / Lapsed
US
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Ferroelectric liquid crystal device
Assignee: Canon Inc
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Filing: 1991-05-16
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Granted: 1992-03-24
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Expires: 2011-05-16
Abstract
Abstract A ferroelectric liquid crystal device comprises a pair of opposite electrodes and a ferroelectric liquid crystal disposed between the electrodes. At least one of the opposite electrodes is coated with an insulating film having a thickness of 200 Å or larger. The ferroelectric liquid crystal has a capacitance C LC measured in (nF/cm 2 ) and a spontaneous polarization PS measured in (nC/cm 2 ) and the insulating film has a capacitance Ci measured in (nF/cm 2 ) wherein the magnitudes of C LC , Ps, and Ci satisfy the relationship of Ci≧7·Ps-C.sub.LC.
Inventors
- 👤 Akira Tsuboyama
- 👤 Yutaka Inaba
- 👤 Akio Yoshida
- 👤 Yukio Hanyu
- 👤 Toshiharu Uchimi
- 👤 Masataka Yamashita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:01
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/08; C09K19/10; C09K19/22; C09K19/12; C09K19/126; C09K19/20; C09K19/2007; C09K19/2021; C09K19/28; C09K19/30; C09K19/3001; C09K19/32; C09K19/322; C09K19/34; C09K19/3441; C09K19/42; C09K19/46; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/133345; G02F1/137; G02F1/139; G02F1/141
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
92 words
A chiral smectic liquid crystal device, comprising: a pair of opposite electrodes of which at least one is coated with an insulating film having a thickness of at least 200 Å and a chiral smectic liquid crystal disposed therebetween; the improvement wherein said chiral smectic liquid crystal has a capacitance C LC measured in (nF/cm 2 ) and a spontaneous polarization Ps measured in (nC/cm 2 ) of at least 10, and said insulating film has a capacitance of C LC , Ps and Ci satisfy the relationship of [Ci(nF/cm.sup.2)≧7·Ps(nC/cm.sup.2 -C.sub.LC (nF/cm.sup.2)]Ci≧7·Ps-C.sub.LC.
Claim 2
Dependent Claim
92 words
A chiral smectic liquid crystal device, comprising: a pair of opposite electrodes of which at least one is coated with an insulating film having a thickness of at least 200 Å and a chiral smectic liquid crystal disposed therebetween; the improvement wherein said chiral smectic liquid crystal has a capacitance C LC measured in (nF/cm 2 ) and a spontaneous polarization Ps measured in (nC/cm 2 ) of at least 10, and said insulating film has a capacitance of C LC , Ps and Ci satisfy the relationship of [Ci(nF/cm.sup.2)≧7·Ps(nC/cm.sup.2 -C.sub.LC (nF/cm.sup.2)]Ci≧7·Ps-C.sub.LC.
Claim 3
Dependent Claim
35 words
A device according to claim 1, wherein said insulating film comprises a first film for preventing short circuit between the opposite electrodes and a second film for controlling alignment of the chiral smectic liquid crystal.
Claim 4
Dependent Claim
17 words
A device according to claim 2, wherein said first film is formed on both the opposite electrodes.
Claim 5
Dependent Claim
19 words
A device according to claim 2, wherein said first film is formed on only one of the opposite electrodes.
Claim 6
Dependent Claim
17 words
A device according to claim 2, wherein said second film is formed on both the opposite electrodes.
Claim 7
Dependent Claim
19 words
A device according to claim 2, wherein said second film is formed on only one of the opposite electrodes.
Claim 8
Dependent Claim
51 words
A device according to claim 1, wherein said insulating film comprises a film which includes at least one insulating material selected from the group consisting of BaTiO 3 , SiO, SiO 2 , TiO, SnO 2 , Si 3 N 4 , polyimide, polyamide-imide, polyester-imide, polyamide, polyvinyl alcohol, polyester and polyethylene.
Claim 9
Dependent Claim
44 words
A device according to claim 2, wherein said first film comprises a film which includes at least one insulating material selected from the group consisting of BaTiO 3 , SiO, SiO 2 , TiO 2 , SnO 2 and Si 3 N 4 .
Claim 10
Dependent Claim
45 words
A device according to claim 2, wherein said second film comprises a film which includes at least one insulating material selected from the group consisting of polyimide, polyamide-imide, polyester-imide, polyamide, polyvinyl alcohol, polyester and polyethylene, and which is also provided with a uniaxial orientation axis.
Claim 11
Dependent Claim
18 words
A device according to claim 2, wherein said second film has a thickness of 500 Å or smaller.
Claim 12
Dependent Claim
17 words
A device according to claim 2, wherein said first film has a thickness of 100 Å-5000 Å.
Claim 13
Dependent Claim
31 words
A device according to claim 1, wherein said chiral smectic liquid crystal is disposed in a layer thin enough to release its helical structure in the absence of an electric field.
Claim 14
Dependent Claim
23 words
A device according to claim 1, wherein said insulating film has a thickness in the range of from 500 Å to 2000 Å.
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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) | 1995-03-24 | 1995-09-23 | 1996-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-24 | 1999-09-23 | 2000-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-24 | 2003-09-23 | 2004-03-24 | $7700.00 | Window Closed / Lapsed |