US3924324A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making electret
Assignee: Sony Corp
•
Filing: 1974-07-02
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Granted: 1975-12-09
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Expires: 1994-07-02
Abstract
Abstract A method of making an electret by annealing a corona charged dielectric film on a metal plate is disclosed.
Inventors
- 👤 Yoichi Kodera
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 01:24
CPC Classifications
H; H01; H01G; H01G7/00; H01G7/02; H01G7/021; H01G7/023; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
53 words
A method of making a mono-charge electret, comprising the steps of charging a dielectric film which is mounted on a metal electrode by subjecting said film to a corona discharge; and then, after said corona discharge is completed and while said film is still mounted on said electrode, heating said charged dielectric film.
Claim 2
Independent Claim
53 words
A method of making a mono-charge electret, comprising the steps of charging a dielectric film which is mounted on a metal electrode by subjecting said film to a corona discharge; and then, after said corona discharge is completed and while said film is still mounted on said electrode, heating said charged dielectric film.
Claim 3
Dependent Claim
34 words
A method of making a mono-charge electret as claimed in claim 1 in which said step of heating is carried out at a temperature higher than the glass transition temperature of said dielectric film.
Claim 4
Dependent Claim
21 words
A method of making a mono-charge electret as claimed in claim 1 in which said dielectric film is made of fluoride.
Claim 5
Dependent Claim
22 words
A method of making a mono-charge electret as claimed in claim 1 in which dielectret is charged by a negative corona discharge.
Claim 6
Independent Claim
88 words
A method of making a mono-charge electret, comprising the steps of charging a dielectric film which is mounted on a metal electrode by subjecting said film to a corona discharge to thereby charge one surface of said film with the polarity of said corona discharge; peeling off said charged dielectric film from said electrode; placing said dielectric film on a metal backing with the other surface of said film in contact with said metal backing; and, while said film is on said metal backing, heating said dielectric film.
Claim 7
Independent Claim
88 words
A method of making a mono-charge electret, comprising the steps of charging a dielectric film which is mounted on a metal electrode by subjecting said film to a corona discharge to thereby charge one surface of said film with the polarity of said corona discharge; peeling off said charged dielectric film from said electrode; placing said dielectric film on a metal backing with the other surface of said film in contact with said metal backing; and, while said film is on said metal backing, heating said dielectric film.
Claim 8
Dependent Claim
34 words
A method of making a mono-charge electret as claimed in claim 5, in which said step of heating is carried out at a temperature higher than the glass transition temperature of said dielectric film.
Claim 9
Dependent Claim
21 words
A method of making a mono-charge electret as claimed in claim 5 in which said dielectric film is made of fluoride.
Claim 10
Dependent Claim
23 words
A method of making a mono-charge electret as claimed in claim 5 in which said dielectret is charged by a negative corona discharge.
References Cited (Backward Citations)
US3660736A
Cited
US3794986A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |