US3873185A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable light-filtering device
Assignee: Polaroid Corp
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Filing: 1973-06-27
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Granted: 1975-03-25
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Expires: 1993-06-27
Abstract
Abstract This invention relates to light filters employing redox compounds that are substantially light-transmitting in their oxidized state and capable of forming a stable colored free radical upon the addition of electrons. The colored free radical formed in response to the flow of electric current renders the device light-absorbing. To restore the original lighttransmitting properties, the colored free radical may be readily reoxidized, for example, by reversing the direction of current flow.
Inventors
- 👤 Howard G Rogers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:10
CPC Classifications
C; C09; C09K; C09K9/00; C09K9/02; F; F21; F21S; F21S41/00; F21S41/10; F21S41/12; F21S41/135; G; G02; G02F; G02F1/00; G02F1/01; G02F1/15; G02F1/1503; G03; G03C; G03C1/00; G03C1/705; G03G; G03G17/00; G03G17/02
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
73 words
In a vehicle having at least one headlamp and a windshield, the improvement which comprises positioning in coextensive relationship with said windshield a variable light-filtering device comprising a pair of spaced, parallel, coextensive lighttransmitting electrodes, a layer of a light-transmitting redox compound capable of forming a stable colored free radical upon the addition of electrons confined between said electrodes and means for flowing an electric current in a predetermined direction through said device.
Claim 2
Dependent Claim
73 words
In a vehicle having at least one headlamp and a windshield, the improvement which comprises positioning in coextensive relationship with said windshield a variable light-filtering device comprising a pair of spaced, parallel, coextensive lighttransmitting electrodes, a layer of a light-transmitting redox compound capable of forming a stable colored free radical upon the addition of electrons confined between said electrodes and means for flowing an electric current in a predetermined direction through said device.
Claim 3
Dependent Claim
22 words
A vehicle as defined in claim 1 wherein said redox compound is a 4,4''-dipyridylium compound, a diazapyrenium compound or a pyrazidinium compound.
Claim 4
Dependent Claim
83 words
In a vehicle having at least one headlamp including a light bulb and a protective transparent cover and a windshield, the improvement which comprises positioning in coextensive relationship with said transparent cover a variable light-filtering device comprising a pair of spaced, parallel, coextensive light-transmitting electrodes, a layer of a light-transmitting redox compound capable of forming a stable colored free radical upon the addition of electrons confined between said electrodes and means for flowing an electric current in a predetermined direction through said device.
Claim 5
Dependent Claim
83 words
In a vehicle having at least one headlamp including a light bulb and a protective transparent cover and a windshield, the improvement which comprises positioning in coextensive relationship with said transparent cover a variable light-filtering device comprising a pair of spaced, parallel, coextensive light-transmitting electrodes, a layer of a light-transmitting redox compound capable of forming a stable colored free radical upon the addition of electrons confined between said electrodes and means for flowing an electric current in a predetermined direction through said device.
Claim 6
Dependent Claim
70 words
A vehicle as defined in claim 3 which additionally includes a light-filtering device positioned in coextensive relationship with said windshield, said light-filtering device comprising a pair of spaced, parallel, coextensive light-transmitting electrodes, a layer of a light-transmitting redox compound capable of forming a stable colored free radical upon the addition of electrons confined between said electrodes, and means for flowing an electric current in a predetermined direction through said device.
Claim 7
Dependent Claim
22 words
A vehicle as defined in claim 4 wherein said redox compound is a 4,4''-dipyridylium compound, a diazapyrenium compound or a pyrazidinium compound.
Claim 8
Dependent Claim
14 words
A vehicle as defined in claim 1 wherein said redox compound is a polymer.
Claim 9
Dependent Claim
15 words
A device according to claim 1 including means for reversing the direction of current flow.
Claim 10
Dependent Claim
16 words
A device according to claim 7 including means for automatically predetermining said direction of current flow.
Claim 11
Dependent Claim
23 words
A vehicle as defined in claim 6 wherein said headlamp contains light-polarizing means and said redox compound is a molecularly oriented redox polymer.
Claim 12
Dependent Claim
66 words
A vehicle as defined in claim 9 wherein said headlamp light-polarizing means comprises a variable light-filtering device comprising a pair of spaced, parallel, coextensive light-transmitting electrodes, a layer of a light-transmitting molecularly oriented redox polymer capable of forming a stable colored free radical upon the addition of electrons confined between said electrodes, and means for flowing an electric current in a predetermined direction through said device.
Claim 13
Dependent Claim
40 words
A vehicle as defined in claim 9 wherein said variable light-filtering device in coextensive relationship with said windshield includes a light-polarizing sheet substantially coextensive with and having one surface in juxtaposition with the outer surface of one of said electrodes.
Claim 14
Dependent Claim
15 words
A vehicle as defined in claim 9 wherein said polymer is a 4, 4''-dipyridylium polymer.
Claim 15
Dependent Claim
14 words
A vehicle as defined in claim 12 wherein said polymer is poly-N,n-butylene-4,4'' -dipyridylium dibromide.
Claim 16
Dependent Claim
19 words
A vehicle as defined in claim 1 wherein said redox compound is capable of functioning as its own electrolyte.
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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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |