Patent US4196974A successfully refreshed from Google Patents.
US4196974A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Smectic liquid crystal display cell
Assignee: Thales SA
•
Filing: 1977-11-29
•
Granted: 1980-04-08
•
Expires: 1997-11-29
Abstract
Abstract The invention provides a liquid crystal display cell in which particles having a preferential light absorption direction, particles which may be the molecules of a dichroic pigment, are inserted in the body of a layer of a mesomorphic material in a smectic state. The write-in can be made by a thermo-optical process. The molecular orientation of the smectic material controls the particles orientation, so that the variation in the light scattering coefficient commonly used with smectic layers are replaced by variations in the absorption coefficient, easier to use and provide a better contrast.
Inventors
- 👤 Michel Hareng
- 👤 Serge Le Berre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:40
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/132; C; C09; C09K; C09K19/00; C09K19/02; C09K19/52; C09K19/60; C09K19/601; G02F1/137; G02F1/13725; C09K19/04; C09K19/06; C09K19/08; C09K19/10; C09K19/12; C09K2019/121; C09K2019/122
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
89 words
A liquid crystal cell comprising: two plates, at least one of them being transparent; a layer of a material having a smectic mesomorphic state; said layer being inserted between said plates and containing in dispersion particles exhibiting a preferential light absorption direction; means for providing heat pulses to at least a selected part of said layer; said layer being in said smectic state at least in the absence of said heat pulses and the molecular orientation of said material in said smectic state controlling the orientation of said particles.
Claim 2
Dependent Claim
89 words
A liquid crystal cell comprising: two plates, at least one of them being transparent; a layer of a material having a smectic mesomorphic state; said layer being inserted between said plates and containing in dispersion particles exhibiting a preferential light absorption direction; means for providing heat pulses to at least a selected part of said layer; said layer being in said smectic state at least in the absence of said heat pulses and the molecular orientation of said material in said smectic state controlling the orientation of said particles.
Claim 3
Dependent Claim
17 words
A cell as claimed in claim 1, wherein said particles are the molecules of a dichroic pigment.
Claim 4
Dependent Claim
38 words
A cell as claimed in claim 1, which further comprises a treatment of at least one surface arranged on at least one said plate in contact with said layer for promoting a preferential molecular orientation of said material.
Claim 5
Dependent Claim
23 words
A cell as claimed in claim 1, which further comprises a substance dissolved in said material for promoting a preferential molecular orientation thereof.
Claim 6
Dependent Claim
22 words
A cell as claimed in claim 1, which further comprises at least two electrodes for subjecting said layer to an electrical field.
Claim 7
Dependent Claim
28 words
A cell as claimed in claim 5, wherein each of said plates supports at least one of said electrodes, the electrode supported by said transparent plate being transparent.
References Cited (Backward Citations)
US3800050A
Cited
US3796999A
Cited
US3864022A
Cited
US4040047A
Cited
US4032219A
Cited
US4059340A
Cited
US4099857A
Cited
DE2627215A1
Cited
US4139273A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-08 | 1983-10-08 | 1984-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-08 | 1987-10-08 | 1988-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-08 | 1991-10-08 | 1992-04-08 | $7700.00 | Window Closed / Lapsed |