US3712709A
Expired / Lapsed
US
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Variable light transmission device
Assignee: Imperial Chemical Industries Ltd
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Filing: 1971-11-22
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Granted: 1973-01-23
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Expires: 1991-11-22
Abstract
Abstract Device for light transmission control in response to electrical signals. A N-substituted p-cyanophenyl derivative of, for example, a bipyridyl is reversibly transformed between the cationic form (colorless) and radical (usually green) by application of potential between a transparent conducting electrode and a counter electrode.
Inventors
- 👤 J Kenworthy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:10
CPC Classifications
C; C09; C09K; C09K9/00; C09K9/02; G; G02; G02F; G02F1/00; G02F1/01; G02F1/15; G02F1/1503
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
24 words
A device according to claim 1 in which the counter electrode obstructs not more than 10 percent of the working area of the device.
Claim 2
Dependent Claim
17 words
A device according to claim 1 in which thE working electrode is a tin oxide coated glass.
Claim 3
Dependent Claim
15 words
A device according to claim 1 in which the active material is a N,N''-di(p-cyanophenyl)-4,4''-bipyridyl salt.
Claim 4
Dependent Claim
26 words
A device according to claim 1 in which the active material is a copolymer of polyvinyl alcohol and polyvinyl chloracetate quaternized with a 4-(4-pyridyl)N-p-cyanophenyl pyridinium salt.
Claim 5
Dependent Claim
19 words
A device according to claim 1 in which the counter electrode is a silver wire coated with silver chloride.
Claim 6
Dependent Claim
19 words
A device according to claim 1 in which a water soluble ferrocyanide salt is added to the active material.
References Cited (Backward Citations)
US3652149A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-23 | 1976-07-24 | 1977-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-23 | 1980-07-24 | 1981-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-23 | 1984-07-24 | 1985-01-23 | $7700.00 | Window Closed / Lapsed |