US4458161A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electret device
Assignee: Toshiba Corp
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Filing: 1982-05-13
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Granted: 1984-07-03
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Expires: 2002-05-13
Abstract
Abstract An electret device having improved uniformity and lifetime of surface charge distribution, wherein a polarized dielectric body is secured at its one flat surface to a conductive electrode and attached to a plurality of discrete cover bodies at its other flat surface opposite to the conductive electrode. The plurality of cover bodies may be comprised of any conductive, semi-conductive or non-conductive material.
Inventors
- 👤 Hiroto Wada
- 👤 Shigeru Fujiwara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:15
CPC Classifications
H; H01; H01G; H01G7/00; H01G7/02; H01G7/021; H01G7/023
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
134 words
An electret device comprising: a dielectric body provided with a surface electric charge and adapted to retain said charge when the electret device is not in operation, said body having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; and a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart and being electrically isolated from each other during operation of the device, and said cover bodies forming an integral part of the electret device, whereby the electret device possesses a substantially uniform surface charge distribution.
Claim 2
Dependent Claim
134 words
An electret device comprising: a dielectric body provided with a surface electric charge and adapted to retain said charge when the electret device is not in operation, said body having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; and a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart and being electrically isolated from each other during operation of the device, and said cover bodies forming an integral part of the electret device, whereby the electret device possesses a substantially uniform surface charge distribution.
Claim 3
Dependent Claim
19 words
An electret device according to claim 1, wherein said plurality of cover bodies are comprised of a conductive material.
Claim 4
Dependent Claim
23 words
An electret device according to claim 2 further comprising a non-conductive cover attached on the top of said plurality of conductive cover bodies.
Claim 5
Dependent Claim
94 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; and a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a non-conductive material.
Claim 6
Dependent Claim
94 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; and a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a non-conductive material.
Claim 7
Dependent Claim
20 words
An electret device according to claim 4, wherein said plurality of non-conductive cover bodies are formed from an organic substance.
Claim 8
Dependent Claim
20 words
An electret device according to claim 4, wherein said plurality of non-conductive cover bodies are formed from an inorganic substance.
Claim 9
Dependent Claim
94 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; and a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a semi-conductive material.
Claim 10
Dependent Claim
94 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; and a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a semi-conductive material.
Claim 11
Dependent Claim
108 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a conductive material; and a semi-conductive cover attached on the top of said plurality of conductive cover bodies.
Claim 12
Dependent Claim
108 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a conductive material; and a semi-conductive cover attached on the top of said plurality of conductive cover bodies.
Claim 13
Dependent Claim
117 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a conductive material; and a non-conductive cover attached on the top of said plurality of conductive cover bodies, said non-conductive cover being formed from an inorganic substance.
Claim 14
Dependent Claim
117 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a conductive material; and a non-conductive cover attached on the top of said plurality of conductive cover bodies, said non-conductive cover being formed from an inorganic substance.
Claim 15
Dependent Claim
117 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a conductive material; and a non-conductive cover attached on the top of said plurality of conductive cover bodies, said non-conductive cover being formed from an organic substance.
Claim 16
Dependent Claim
117 words
An electret device comprising: a dielectric body provided with a surface electric charge and having two substantially flat and generally parallel surfaces; a conductive electrode having a substantially flat surface which is rigidly secured on one of said flat surfaces of the dielectric body, said conductive electrode forming an integral part of the electret device; a plurality of cover bodies rigidly attached on the opposite one of said flat surfaces of the dielectric body, said plurality of cover bodies being laterally spaced apart from each other and being comprised of a conductive material; and a non-conductive cover attached on the top of said plurality of conductive cover bodies, said non-conductive cover being formed from an organic substance.
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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) | 1987-07-03 | 1988-01-02 | 1988-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-03 | 1992-01-02 | 1992-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-03 | 1996-01-02 | 1996-07-03 | $7700.00 | Window Closed / Lapsed |