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Patent US4142073A successfully refreshed from Google Patents.
US4142073A
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US
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Temperature-stable electret microphone with embossed, small area, electret
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1978-03-06
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Granted: 1979-02-27
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Expires: 1998-03-06
Abstract
Abstract Temperature-stable electret microphone with a metallized plastic film stretched over a polarized plastic film and fastened to an underlying fixed electrode, the polarized plastic film being on at least one side embossed with a relief pattern, having a smaller area than the underlying fixed electrode and being concentrically fixed to this by the metallized plastic film.
Inventors
- 👤 Nils-Erik Agneus
- 👤 Hans-Eric Mansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:00
CPC Classifications
H; H04; H04R; H04R19/00; H04R19/01; H04R19/016
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
56 words
Temperature-stable electret microphone with a metallized plastic film stretched over a polarized plastic film and fastened to an underlying fixed electrode, the polarized plastic film being on at least one side embossed with a relief pattern, having a smaller area than the underlying fixed electrode and being concentrically fixed to this by the metallized plastic film.
Claim 2
Dependent Claim
56 words
Temperature-stable electret microphone with a metallized plastic film stretched over a polarized plastic film and fastened to an underlying fixed electrode, the polarized plastic film being on at least one side embossed with a relief pattern, having a smaller area than the underlying fixed electrode and being concentrically fixed to this by the metallized plastic film.
References Cited (Backward Citations)
SU293280A1
Cited
US3328653A
Cited
USRE28420E
Cited
US3821490A
Cited
US4070741A
Cited
US4063050A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-26 | 1982-08-28 | 1983-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-26 | 1986-08-28 | 1987-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-26 | 1990-08-28 | 1991-02-27 | $7700.00 | Window Closed / Lapsed |