US3474197A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electret microphone
Assignee: Tesla AS
•
Filing: 1965-10-13
•
Granted: 1969-10-21
•
Expires: 1985-10-13
Abstract
No abstract record available.
Inventors
- 👤 Vlastimil Koukal
- 👤 Otokar Krakora
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:51
CPC Classifications
H; H04; H04R; H04R19/00; H04R19/005; C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682; C04B35/4684; H01; H01G; H01G7/00; H01G7/02; H01G7/025; H01G7/026; H04R19/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3118022A
Cited
US3301786A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-10-20 | 1973-04-21 | 1973-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-10-20 | 1977-04-21 | 1977-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-10-20 | 1981-04-21 | 1981-10-21 | $7700.00 | Window Closed / Lapsed |