US3703331A
Expired / Lapsed
US
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Liquid crystal display element having storage
Assignee: RCA Corp
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Filing: 1971-11-26
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Granted: 1972-11-21
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Expires: 1991-11-26
Abstract
Abstract A liquid crystal element exhibiting storage of its light scattering state after removal of the electric current initiating the state comprises a mixture of cholesterol, a cholesterol derivative or a cholesteric liquid crystal compound with a nematic liquid crystal of the type that exhibits non-destructive turbulent motion when an electrical current of sufficient magnitude is passed therethrough.
Inventors
- 👤 Joel E Goldmacher
- 👤 George H Heilmeier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:37
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/13718; C; C09; C09K; C09K19/00; C09K19/04; C09K19/06; C09K19/08; C09K19/10; C09K19/22; C09K19/42; C09K19/50
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
21 words
A liquid crystal element according to claim 1 including AC voltage means coupled thereto for erasing images formed on said element.
Claim 2
Dependent Claim
131 words
A light scattering device comprising a substantially transparent layer of a liquid crystal mixture of at least one nematic liquid crystal compound having the formula wherein X and Y are selected from the group consisting of alkoxy radicals and acyloxy radicals, said alkoxy radicals having from one to nine carbon atoms and said acyloxy radicals having from two to five carbon atoms, with the proviso that X and Y are different and when said acyloxy radical has only two carbon atoms, said alkoxy radical has at least three carbon atoms, with at least one member of the group consisting of cholesterol derivatives, said liquid crystal mixture being supported between support plates at least one of which is transparent, and electrode means for applying an exciting voltage to said liquid crystal layer.
Claim 3
Dependent Claim
23 words
A light scattering device according to claim 3 wherein said mixture contains from 50-95 percent by weight for said nematic liquid crystal component.
Claim 4
Dependent Claim
23 words
A light scattering device according to claim 3 wherein said mixture contains from 75-95 percent by weight of said nematic liquid crystal component.
Claim 5
Dependent Claim
31 words
The light scattering device recited in claim 3 wherein the nematic liquid crystal component of said mixture comprises at least one member of the group consisting of anisylidene-p-aminophenylacetate, p-butoxy-benzylidene-p''-aminophenylacetate and anisylidene-p-aminophenyl-butyrate.
Claim 6
Dependent Claim
42 words
The light scattering device recited in claim 6 wherein the nematic liquid crystals anisylidene-p-aminophenyl-acetate, p-butoxybenzylidene-p''-aminophenylacetate and anisylidene-p-aminophenylbutyrate are present in equal proportions by weight and wherein these nematic materials comprise between 80 to 90 percent of the total weight of the mixture.
Claim 7
Dependent Claim
31 words
The light scattering device recited in claim 3 wherein said cholesterol derivative comprises cholesteryl chloride and cholesteryl oleate in a weight ratio of cholesteryl chloride to cholesteryl oleate of approximately 1:3.
Claim 8
Independent Claim
168 words
A method of operating a liquid crystal device containing a mixture of at least one nematic liquid crystal compound of The formula wherein X and Y are selected from the group consisting of alkoxy radicals and acyloxy radicals, said alkoxy radicals having from one to nine carbon atoms and said acyloxy radicals having from two to five carbon atoms, with the proviso that X and Y are different and when said acyloxy radical has only two carbon atoms, said alkoxy radical has at least three carbon atoms, and at least one member of the group consisting of cholesterol derivatives, which comprises a. causing light-scattering in the mixture by passing an exciting electric current through the liquid crystal mixture, said electric current being DC or a first frequency AC; b. removing said exciting electric current; and c. erasing the scattering and returning the mixture to its original state by applying a second frequency AC electric field to said mixture, said second frequency being substantially higher than said first frequency.
References Cited (Backward Citations)
US3540796A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-21 | 1976-05-22 | 1976-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-21 | 1980-05-22 | 1980-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-21 | 1984-05-22 | 1984-11-21 | $7700.00 | Window Closed / Lapsed |