US4891843A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electret microphone
Assignee: AT&T Inc
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Filing: 1983-02-24
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Granted: 1990-01-02
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Expires: 2003-02-24
Abstract
Abstract An electret microphone (10) comprises an electret diaphragm (11) having a thin metallic layer (13) deposited on one of its major surfaces. A ring-shaped metal washer (20) bonded to the metallic layer (13) of the diaphragm (11) by means of a lightly metal-filled adhesive (21).
Inventors
- 👤 Frank S. Paulus, Jr.
- 👤 Isaac Tuah-Poku
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:12
CPC Classifications
H; H04; H04R; H04R19/00; H04R19/01
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
64 words
An electret transducer comprising: an electret diaphragm having a thin metal layer deposited on one of its major surfaces; a ring-shaped metal washer made of nickel-plated brass material; and a layer of lightly filled metal-filled adhesive for bonding the electet diaphragm to the metal washer so that the electret diaphragm is uniformly radially tensioned thereby wherein the lightly filled adhesive comprises approximately 4% nickel.
Claim 2
Dependent Claim
64 words
An electret transducer comprising: an electret diaphragm having a thin metal layer deposited on one of its major surfaces; a ring-shaped metal washer made of nickel-plated brass material; and a layer of lightly filled metal-filled adhesive for bonding the electet diaphragm to the metal washer so that the electret diaphragm is uniformly radially tensioned thereby wherein the lightly filled adhesive comprises approximately 4% nickel.
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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) | 1993-01-01 | 1993-07-03 | 1994-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-01 | 1997-07-03 | 1998-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-01 | 2001-07-03 | 2002-01-02 | $7700.00 | Window Closed / Lapsed |