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US3567373A
Expired / Lapsed
US
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Low donor concentration zinc oxide and devices utilizing same
Assignee: AT&T Inc
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Filing: 1967-11-29
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Granted: 1971-03-02
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Expires: 1987-11-29
Abstract
Abstract EFFECTIVE OPERATION OF ACOUSTOELECTRIC DEVICES SUCH AS AMPLIFIERS, OSCILLATORS, CIRCULATORS, ISOLATORS AND SWITCHES REQUIRES HIGH RESISTIVITY SUBSTANTIALLY UNCOMPENSATED MATERIAL. UNCOMPENSATED ZINC OXIDE, OTHERWISE CONSIDERED THE BEST MATERIAL FOR SUCH DEVICES, HAS BEEN UNSUITABLE BY REASON OF ITS LARGE DONOR CONCENTRATION. SUBSTANTIALLY UNCOMPENSATED MATERIAL MAY NOW BE PREPARED BY A TECHNIQUE INVOLVING INTRODUCTION OF (1) LITHIUM DURING HYDROTHERMAL GROWTH, (2) REPLACEMENT OF LITHIUM BY ZINC BY HEATING IN ZINC VAPOR; AND (3) OUT-DIFFUSION OF INTERSTITIAL ZINC BY BAKING IN OXYGEN.
Inventors
- 👤 Andrew R Hutson
- 👤 Robert A Laudise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:02
CPC Classifications
G; G05; G05G; G05G9/00; G05G9/02; G05G9/04; C; C30; C30B; C30B1/00; C30B1/02; H; H10; H10P; H10P95/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |