Patent US3772133A successfully refreshed from Google Patents.
US3772133A
Expired / Lapsed
US
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Backplate construction for electret transducer
Assignee: Industrial Research Products Inc
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Filing: 1971-11-08
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Granted: 1973-11-13
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Expires: 1991-11-08
Abstract
Abstract An electret transducer having a perforate backplate wherein the side of the perforations or holes are coated with a dielectric material.
Inventors
- 👤 T Schmitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:37
CPC Classifications
H; H04; H04R; H04R19/00; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1052; Y10T156/1056; Y10T156/1057; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/24322; Y10T428/24479; Y10T428/24521
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
51 words
A backplate assembly for an electret transducer comprising a backplate having perforations passing from a first to a second surface, a dielectric material film formed on the first surface of the backplate, on the interior surfaces of said perforations, and extending over the edge of said perforations on the second surface.
Claim 2
Dependent Claim
51 words
A backplate assembly for an electret transducer comprising a backplate having perforations passing from a first to a second surface, a dielectric material film formed on the first surface of the backplate, on the interior surfaces of said perforations, and extending over the edge of said perforations on the second surface.
Claim 3
Dependent Claim
33 words
A backplate assembly as in claim 1 wherein the film extending over the edge of said perforations on the second surface provides stable anchoring tabs to securely anchor the film on the backplate.
Claim 4
Dependent Claim
28 words
A backplate assembly as in claim 1 wherein the film tends to covEr any irregularities on the surfaces of said plate and on the surfaces of said perforations.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |