US4464020A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Smectic liquid crystal display device without a nematic phase
Assignee: Thales SA
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Filing: 1982-08-20
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Granted: 1984-08-07
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Expires: 2002-08-20
Abstract
Abstract The invention relates to matrix access display devices using a mixed thermal and electric effect and provides a display device with mixed thermal-electric drive using a smectic liquid crystal deprived of a nematic phase by addition of appropriate dopes.
Inventors
- 👤 Serge Le Berre
- 👤 Michel Hareng
- 👤 Annie Beguin
- 👤 Lydie Thirant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:43
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/132; C; C09; C09K; C09K19/00; C09K19/52; C09K19/58
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
54 words
In a display device comprising a liquid crystal layer having a smectic phase, an isotropic phase, and a smectic-isotropic phase transition, said layer being subjected to a mixed thermal and electric writing effect through heating means and electric field addressing means, said smectic-isotropic phase transition consisting of a smectic phase and an isotropic phase.
Claim 2
Dependent Claim
54 words
In a display device comprising a liquid crystal layer having a smectic phase, an isotropic phase, and a smectic-isotropic phase transition, said layer being subjected to a mixed thermal and electric writing effect through heating means and electric field addressing means, said smectic-isotropic phase transition consisting of a smectic phase and an isotropic phase.
Claim 3
Dependent Claim
68 words
The display device as claimed in claim 1, wherein said heating means are formed of heating strips which have successively flowing therethrough a heating current and the means for addressing the electric field are formed, on the one hand, by the heating strips and, on the other hand, by an electrode array of further strips, the liquid crystal layer being disposed between said strips and said electrode array.
Claim 4
Dependent Claim
35 words
The display device as claimed in claim 1, wherein said heating means are formed by a laser beam scanning said layer and the electric field addressing means are formed by two electrodes enclosing said layer.
Claim 5
Dependent Claim
21 words
The display device as claimed in claim 1, wherein said layer is a mixture of liquid crystals, said mixture being doped.
Claim 6
Dependent Claim
31 words
The display device as claimed in claim 4, wherein said mixture comprises a smectic liquid crystal having the composition: ##STR7## said doping agent being bicyclootene-2 in a proportion more than 10%.
References Cited (Backward Citations)
US3114836A
Cited
US3410999A
Cited
US3796999A
Cited
US4150396A
Cited
US3988056A
Cited
US3999838A
Cited
FR2373076A1
Cited
US4402855A
Cited
US4391492A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-07 | 1988-02-06 | 1988-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-07 | 1992-02-06 | 1992-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-07 | 1996-02-06 | 1996-08-07 | $7700.00 | Window Closed / Lapsed |