US5126867A
Expired / Lapsed
US
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Liquid crystal device having insulating and alignment films wherein three ≧-CR[-2.3+ln(C/Ps)]
Assignee: Canon Inc
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Filing: 1990-09-28
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Granted: 1992-06-30
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Expires: 2010-09-28
Abstract
Abstract A liquid crystal device is formed by disposing a chiral smectic liquid crystal between two groups of electrodes which are disposed opposite to each other and so as to intersect each other. At least one of the two groups of electrodes is covered by an insulating film and an alignment film which are selected and disposed to provide a combined electrostatic capacitance C (nF) and a combined resistance R (Ω) satisfying a relationship with the spontaneous polarization Ps of the chiral smectic liquid crystal represented by the following formula: 3≧-CR[-2.3+ln(C/Ps)]. As a result, there is provided a chiral smectic liquid crystal device which suppress the persistence to a tolerable level while retaining a good switching characteristic.
Inventors
- 👤 Kazuya Ishiwata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:53
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/133345; G02F1/1337; G02F1/137; G02F1/139; G02F1/141
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
105 words
A liquid crystal device, comprising: two groups of electrodes disposed opposite to each other so as to intersect each other, a chiral smectic liquid crystal disposed between the two groups of electrodes, an insulating film comprising tantalum oxide disposed on at least one group of the electrodes, and an alignment film disposed on the insulating film; wherein the insulating film and the alignment film are selected and disposed to provide a combined electrostatic capacitance C(nF) and a combined resistance R (Ω) satisfying a relationship according to the following formula: 3≧--CR(-2.3+1n(C/Ps)), wherein Ps denotes the spontaneous polarization (nc/cm 2 ) of the chiral smectic liquid crystal.
Claim 2
Dependent Claim
105 words
A liquid crystal device, comprising: two groups of electrodes disposed opposite to each other so as to intersect each other, a chiral smectic liquid crystal disposed between the two groups of electrodes, an insulating film comprising tantalum oxide disposed on at least one group of the electrodes, and an alignment film disposed on the insulating film; wherein the insulating film and the alignment film are selected and disposed to provide a combined electrostatic capacitance C(nF) and a combined resistance R (Ω) satisfying a relationship according to the following formula: 3≧--CR(-2.3+1n(C/Ps)), wherein Ps denotes the spontaneous polarization (nc/cm 2 ) of the chiral smectic liquid crystal.
Claim 3
Dependent Claim
20 words
A liquid crystal device according to claim 1, wherein said insulating film has a thickness of 400 Å or larger.
Claim 4
Dependent Claim
25 words
A liquid crystal device according to claim 1, wherein said alignment film comprises a film of polyimide having a thickness of 100 Å or smaller.
Claim 5
Dependent Claim
25 words
A liquid crystal device according to claim 1, where said alignment film comprises a film of polyimide having a thickness of 50 Å or smaller.
Claim 6
Dependent Claim
24 words
A liquid crystal device according to claim 1, wherein said chiral smectic liquid crystal has a spontaneous polarization Ps of 8.5 nC/cm 2 .
Claim 7
Dependent Claim
25 words
A liquid crystal device according to claim 1, wherein said alignment film comprises a film of polyimide having a thickness of 50 Å or smaller.
Claim 8
Dependent Claim
120 words
A liquid crystal device comprising: two groups of electrodes disposed opposite to each other so as to intersect each other, a chiral smectic liquid crystal disposed between the two groups of electrodes, an insulating film disposed on at least one group of the electrodes, and an alignment film disposed on the insulating film; wherein the insulating film and the alignment film are selected and disposed to provide a combined electrostatic capacitance C(nF) and a combined resistance R (Ω) satisfying a relationship according to the following formula: 3>--CR(-2.3+1n(C/Ps)), wherein Ps denotes the spontaneous polarization (nC/cm 2 ) of the chiral smectic liquid crystal and said insulating film and alignment film provide a combined electrostatic capacitance C of 96 nF or larger.
Claim 9
Dependent Claim
120 words
A liquid crystal device comprising: two groups of electrodes disposed opposite to each other so as to intersect each other, a chiral smectic liquid crystal disposed between the two groups of electrodes, an insulating film disposed on at least one group of the electrodes, and an alignment film disposed on the insulating film; wherein the insulating film and the alignment film are selected and disposed to provide a combined electrostatic capacitance C(nF) and a combined resistance R (Ω) satisfying a relationship according to the following formula: 3>--CR(-2.3+1n(C/Ps)), wherein Ps denotes the spontaneous polarization (nC/cm 2 ) of the chiral smectic liquid crystal and said insulating film and alignment film provide a combined electrostatic capacitance C of 96 nF or larger.
Claim 10
Dependent Claim
25 words
A liquid crystal device according to claim 7, wherein said alignment film comprises a film of polyimide having a thickness of 100 Å or smaller.
Claim 11
Dependent Claim
24 words
A liquid crystal device according to claim 7, wherein said chiral smectic liquid crystal has a spontaneous polarization Ps of 8.5 nC/cm 2 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-06-30 | 1995-12-30 | 1996-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-30 | 1999-12-30 | 2000-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-30 | 2003-12-30 | 2004-06-30 | $7700.00 | Window Closed / Lapsed |