Patent US3574681A successfully refreshed from Google Patents.
US3574681A
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Aluminum oxide humidity sensor
Assignee: Texas Instruments Inc
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Filing: 1968-10-09
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Granted: 1971-04-13
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Expires: 1988-10-09
Abstract
Abstract AN ALUMINUM OXIDE HUMIDITY SENSOR IS FABRICATED BY A SEQUENCE OF STEPS BEGINNING WITH THE ANODIZATION OF AN ALUMINUM BODY TO FORM A SURFACE LAYER OF DENSE ALUMINUM OXIDE ON THE ALUMINUM BODY AND A LAYER OF POROUS ALUMINUM OXIDE ON THE DENSE LAYER. THE POROUS ALUMINUM OXIDE IS THEN SEPARATED FROM THE DENSE ALUMINUM OXIDE, AND AN ELECTRODE IS FORMED ON EACH OF THE OPPOSITE FACES OF THE ALUMINUM OXIDE, AT LEAST ONE OF THE ELECTRODES BEING PERVIOUS TO WATER VAPOR.
Inventors
- 👤 Olin B Cecil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:41
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/121; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |