US4932758A
Expired / Lapsed
US
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Ferroelectric smectic liquid crystal device having a bistable alignment state providing two stable orientation states
Assignee: Canon Inc
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Filing: 1988-09-16
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Granted: 1990-06-12
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Expires: 2008-09-16
Abstract
Abstract A ferroelectric smectic liquid crystal device having an improved impact resistance and an improved contrast is provided by using a pair of substrates provided with uniaxial alignment axes which are parallel and identical in direction with each other. A ferroelectric smectic liquid crystal is disposed between the pair of substrates so as to assume a higher-temperature alignment state and a lower-temperature alignment state on temperature decrease in its ferroelectric smectic phase placed in a bistable alignment state. The ferroelectric smectic liquid crystal is further placed in the lower-temperature alignment state which is characterized by having an inclination of forming a connected pair of a lightning defect and a hair pin defect coming after the lightning defect.
Inventors
- 👤 Yukio Hanyu
- 👤 Junichiro Kanbe
- 👤 Hideyuki Kawagishi
- 👤 Yutaka Inaba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:18
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141; G02F1/1416
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
84 words
A ferroelectric smectic liquid crystal device, comprising: (a) a pair of substrates each provided with a uniaxial alignment axis; (b) a ferroelectric smectic liquid crystal disposed between the pair of substrates and capable of forming a higher-temperature alignment state and a lower-temperature alignment state in its ferroelectric smectic phase placed in a bistable alignment state providing two stable orientation states, said ferroelectric smectic liquid crystal being further placed in the lower-temperature alignment state; and (c) means for optically discriminating the two stable orientation states.
Claim 2
Dependent Claim
84 words
A ferroelectric smectic liquid crystal device, comprising: (a) a pair of substrates each provided with a uniaxial alignment axis; (b) a ferroelectric smectic liquid crystal disposed between the pair of substrates and capable of forming a higher-temperature alignment state and a lower-temperature alignment state in its ferroelectric smectic phase placed in a bistable alignment state providing two stable orientation states, said ferroelectric smectic liquid crystal being further placed in the lower-temperature alignment state; and (c) means for optically discriminating the two stable orientation states.
Claim 3
Dependent Claim
27 words
A device according to claim 1, wherein said lower-temperature alignment state is developed at a temperature of 30° C. or above in the course of temperature decrease.
Claim 4
Dependent Claim
27 words
A device according to claim 1, wherein said lower-temperature alignment state is developed at a temperature of 40° C. or above in the course of temperature decrease.
Claim 5
Dependent Claim
16 words
A device according to claim 1, wherein said ferroelectric smectic phase is chiral smectic C phase.
Claim 6
Dependent Claim
114 words
A ferroelectric smectic liquid crystal device, comprising: (a) a pair of substrates each provided with a uniaxial alignment axis, the alignment axes on the pair of substrates being substantially parallel with each other and having an identical axis direction; (b) a ferroelectric smectic liquid crystal disposed between the pair of substrates in a bistable alignment state providing two stable orientation states having an inclination of forming a connected pair of a hair pin defect and a lightning defect and further in such a first alignment state that the hair pin defect is formed after the lightning defect in the uniaxial alignment axis direction; and (c) means for optically discriminating the two stable orientation states.
Claim 7
Dependent Claim
114 words
A ferroelectric smectic liquid crystal device, comprising: (a) a pair of substrates each provided with a uniaxial alignment axis, the alignment axes on the pair of substrates being substantially parallel with each other and having an identical axis direction; (b) a ferroelectric smectic liquid crystal disposed between the pair of substrates in a bistable alignment state providing two stable orientation states having an inclination of forming a connected pair of a hair pin defect and a lightning defect and further in such a first alignment state that the hair pin defect is formed after the lightning defect in the uniaxial alignment axis direction; and (c) means for optically discriminating the two stable orientation states.
Claim 8
Dependent Claim
35 words
A device according to claim 5, wherein a domain in said first alignment state occupies a major proportion to have a domain in another alignment state occupying a minor proportion in the entire device area.
Claim 9
Dependent Claim
38 words
A device according to claim 6, wherein said domain in said first alignment state has been grown to occupy a major portion on temperature decrease until the domain in said another alignment state occupy only a minor proportion.
Claim 10
Dependent Claim
51 words
A device according to claim 7, wherein a temperature range where the domain in said another alignment state occupies not a minor proportion is 1/5 or less of a temperature range where the domain in said another alignment state occupies a minor proportion, respectively in the course of the temperature decrease.
Claim 11
Dependent Claim
51 words
A device according to claim 7, wherein a temperature range where the domain in said another alignment state occupies not a minor proportion is 1/10 or less of a temperature range where the domain in said another alignment state occupies a minor proportion, respectively in the course of the temperature decrease.
Claim 12
Dependent Claim
51 words
A device according to claim 7, wherein a temperature range where the domain in said another alignment state occupies not a minor proportion is 1/20 or less of a temperature range where the domain in said another alignment state occupies a minor proportion, respectively in the course of the temperature decrease.
Claim 13
Dependent Claim
39 words
A device according to claim 7, wherein the lower limit of a temperature range where the domain in said another alignment state occupies not a minor proportion in 30° C. or above in the course of the temperature decrease.
Claim 14
Dependent Claim
39 words
A device according to claim 7, wherein the lower limit of a temperature range where the domain in said another alignment state occupies not a minor proportion in 40° C. or above in the course of the temperature decrease.
Claim 15
Dependent Claim
41 words
A device according to claim 6, wherein the domain in said another alignment state is present in the neighborhood region of a sealing member in a cell, and the domain in said first alignment state is present inside the neighborhood region.
Claim 16
Dependent Claim
39 words
A device according to claim 6, wherein said another alignment state has an inclination of forming a connected pair of a hair pin defect and a lightning defect wherein the lightning defect is formed after the hair pin defect.
Claim 17
Dependent Claim
28 words
A device according to claim 5, wherein the two stable orientation states in the domain in said first alignment state are optically equivalent respectively in the extinction position.
Claim 18
Dependent Claim
23 words
A device according to claim 5, wherein said uniaxial alignment axis has been imparted to an alignment control film formed on a substrate.
Claim 19
Dependent Claim
22 words
A device according to claim 16, wherein said alignment control film comprises a polyimide film, a polyamide film or a polyester film.
Claim 20
Dependent Claim
15 words
A device according to claim 16, wherein said alignment control film comprises a polyimide film.
Claim 21
Dependent Claim
23 words
A device according to claim 16, wherein said alignment control film is formed on the substrate by the medium of an insulating film.
Claim 22
Dependent Claim
15 words
A device according to claim 5, wherein said uniaxial alignment axis is a rubbing axis.
Claim 23
Dependent Claim
18 words
A device according to claim 5, wherein said ferroelectric smectic liquid crystal is in chiral smectic C phase.
Claim 24
Dependent Claim
119 words
A ferroelectric smectic liquid crystal device, comprising: (a) a pair of substrates each provided with a uniaxial alignment axis; (b) a ferroelectric smectic liquid crystal disposed between the pair of substrates in a bistable alignment state providing two stable orientation states, said ferroelectric smectic liquid crystal yielding smectic C phase on a higher temperature side than its ferroelectric smectic phase and the liquid crystal molecules being aligned to form a pre-tilt angle of 2 degrees or larger with respect to a substrate face in the temperature range of the smectic C phase, said ferroelectric smectic liquid crystal having been formed through the smectic A phase on temperature decrease; and (c) means for optically discriminating the two stable orientation states.
Claim 25
Dependent Claim
119 words
A ferroelectric smectic liquid crystal device, comprising: (a) a pair of substrates each provided with a uniaxial alignment axis; (b) a ferroelectric smectic liquid crystal disposed between the pair of substrates in a bistable alignment state providing two stable orientation states, said ferroelectric smectic liquid crystal yielding smectic C phase on a higher temperature side than its ferroelectric smectic phase and the liquid crystal molecules being aligned to form a pre-tilt angle of 2 degrees or larger with respect to a substrate face in the temperature range of the smectic C phase, said ferroelectric smectic liquid crystal having been formed through the smectic A phase on temperature decrease; and (c) means for optically discriminating the two stable orientation states.
Claim 26
Dependent Claim
15 words
A device according to claim 22, wherein said pre-tilt angle is 3 degrees or larger.
Claim 27
Dependent Claim
23 words
A device according to claim 22, wherein said uniaxial alignment axis has been imparted to an alignment control film formed on a substrate.
Claim 28
Dependent Claim
15 words
A device according to claim 24, wherein said alignment control film comprises a polyimide film.
Claim 29
Dependent Claim
23 words
A device according to claim 24, wherein said alignment control film is formed on the substrate by the medium of an insulating film.
Claim 30
Dependent Claim
15 words
A device according to claim 22, wherein said uniaxial alignment axis is a rubbing axis.
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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) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |