US3961301A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Humidity sensor
Assignee: Plessey Inc
•
Filing: 1973-12-13
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Granted: 1976-06-01
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Expires: 1993-12-13
Abstract
Abstract The operation of relative humidity sensors made from cobalt oxide on a non-conductive ceramic substrate is improved by (1) providing a porous, sputtered overcoat of polytetrafluoroethylene which renders the sensor surface non-wettable without affecting other properties, and (2) providing a printed heating element on the back surface of the sensor, enabling in situ degassing of chemisorbed or adsorbed impurities and regeneration of a nascent sensor surface.
Inventors
- 👤 Anthony V. Fraioli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:44
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/121
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
44 words
A humidity sensor comprising: a high-temperature resistant dielectric substrate; a fired layer of cobalt oxide on a major surface of said substrate; a pair of electrodes in contact with said cobalt oxide; and a porous, non-wettable coating covering at least said cobalt oxide layer.
Claim 2
Dependent Claim
44 words
A humidity sensor comprising: a high-temperature resistant dielectric substrate; a fired layer of cobalt oxide on a major surface of said substrate; a pair of electrodes in contact with said cobalt oxide; and a porous, non-wettable coating covering at least said cobalt oxide layer.
Claim 3
Dependent Claim
14 words
The humidity sensor as claimed in claim 1, wherein said coating is sputtered polytetrafluoroethylene.
Claim 4
Dependent Claim
15 words
The humidity sensor as claimed in claim 1, wherein said substrate is a high-alumina ceramic.
Claim 5
Dependent Claim
43 words
The humidity sensor as claimed in claim 1, wherein said substrate has first and second major surfaces, said oxide layer, electrodes and coating are on said first major surface, and additionally comprising a fired, thick film heating element on said second major surface.
Claim 6
Dependent Claim
58 words
A humidity sensor comprising: a high-temperature resistant dielectric substrate; a fired layer of cobalt oxide on a major surface of said substrate; a porous, non-wetting coating of sputtered polytetrafluoroethylene over said fired layer; a pair of electrodes in contact with said cobalt oxide; and a fired, thick film heating element on the other major surface of said substrate.
Claim 7
Dependent Claim
58 words
A humidity sensor comprising: a high-temperature resistant dielectric substrate; a fired layer of cobalt oxide on a major surface of said substrate; a porous, non-wetting coating of sputtered polytetrafluoroethylene over said fired layer; a pair of electrodes in contact with said cobalt oxide; and a fired, thick film heating element on the other major surface of said substrate.
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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) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |