US5050434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitive humidity sensor
Assignee: Testoterm Messtechnik GmbH and Co
•
Filing: 1990-06-13
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Granted: 1991-09-24
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Expires: 2010-06-13
Abstract
Abstract A capacitive humidity sensor includes a capacitor with two metallic electrodes 12, 15, with electrode 15 formed of a moisture-permeable metallic layer. A moisture-sensitive polymer film 14 situated between the electrodes serves as a dielectric. The film 14 is advantageously chosen to be polyether imide.
Inventors
- 👤 Ullrich Demisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:18
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/22; G01N27/223; G01N27/225
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
46 words
A capacitive humidity sensor, comprising: a) a capacitor with at least two metallic layers forming electrodes, at least one of which is permeable to water vapor; and b) a humidity-sensitive polyimide film disposed between the electrodes as a dielectric, the polyimide film consisting of polyether imide.
Claim 2
Dependent Claim
46 words
A capacitive humidity sensor, comprising: a) a capacitor with at least two metallic layers forming electrodes, at least one of which is permeable to water vapor; and b) a humidity-sensitive polyimide film disposed between the electrodes as a dielectric, the polyimide film consisting of polyether imide.
Claim 3
Dependent Claim
24 words
The capacitive humidity sensor of claim 1, further comprising: a substrate having high electrical insulation properties, on which is disposed a said metallic layer.
Claim 4
Dependent Claim
38 words
The capacitive humidity sensor of claim 1, wherein one of the electrodes is selected from the group consisting of tantalum, tantalum/tantalum oxide, gold, gold/nickel, or silver/palladium; and another of the electrodes is of gold and is water permeable.
Claim 5
Dependent Claim
22 words
The capacitive humidity sensor of claim 3, further comprising a substrate of glass or ceramic, a said electrode being on said substrate.
Claim 6
Dependent Claim
91 words
The capacitive humidity sensor of claim 1, wherein: a first said electrode is provided on a substrate and includes tantalum or tantalum/tantalum oxide; the polyether imide film completely covers the first electrode, the film having a side which is engaged by a second electrode; the second electrode is of gold and is water-vapor permeable and has a laterally projecting edge; and a third electrode is provided on the substrate electrically insulated from the first said electrode, includes tantalum or tantalum/tantalum oxide, and contacts the laterally projecting edge of the second electrode.
Claim 7
Dependent Claim
17 words
The capacitive humidity sensor of claim 1, wherein the polyimide film is set from liquid polyether imide.
Claim 8
Dependent Claim
17 words
The capacitive humidity sensor of claim 1, wherein the polyether imide film is a self-supporting foil film.
Claim 9
Dependent Claim
19 words
The capacitive humidity sensor of claim 1, wherein at least one electrode is evaporated onto the polyether imide film.
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Cited
US4672506A
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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) | 1994-09-23 | 1995-03-25 | 1995-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-23 | 1999-03-25 | 1999-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-23 | 2003-03-25 | 2003-09-24 | $7700.00 | Window Closed / Lapsed |