Patent EP0048902A2 successfully refreshed from Google Patents.
EP0048902A2
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EP
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Method for manufacturing electret device and condenser type electro-acoustic transducer having electrets
Assignee: Toshiba Corp
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Filing: 1981-09-18
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Granted: —
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Expires: 2001-09-18
Abstract
Abstract The invention discloses a method for manufacturing an electret device having the steps of preparing a dielectric material film (11) having metal layers (12, 12 min ) on both surfaces; applying, by a power applying circuit, a DC voltage across said metal layers (12, 12 min ); and opening the power applying circuit while the DC voltage is being applied to stop applying the DC votlage, thereby obtaining an electret. Also disclosed is a condenser type electro-acoustic transducer having electrets as the stationary electrodes (21, 21 min ) which are provided by this method.
Inventors
- 👤 Sakae Tamura
- 👤 Shigeru Fujiwara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 16:16
CPC Classifications
H; H04; H04R; H04R19/00; H04R19/01; H01; H01G; H01G7/00; H01G7/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
63 words
A method for manufacturing an electret device comprising the steps of preparing a dielectric material film (11) having metal layers (12, 12') on both surfaces; applying, by a power applying circuit, a DC voltage across said metal layers (12, 12'); and opening the power applying circuit while the DC voltage is being applied to stop applying the DC voltage, thereby obtaining an electret.
Claim 2
Independent Claim
63 words
A method for manufacturing an electret device comprising the steps of preparing a dielectric material film (11) having metal layers (12, 12') on both surfaces; applying, by a power applying circuit, a DC voltage across said metal layers (12, 12'); and opening the power applying circuit while the DC voltage is being applied to stop applying the DC voltage, thereby obtaining an electret.
Claim 3
Dependent Claim
19 words
A method for manufacturing an electret according to claim 1, wherein the DC voltage is applied at room temperature.
Claim 4
Dependent Claim
11 words
An electret device manufactured by a method according to claim 1.
Claim 5
Dependent Claim
52 words
A condenser type electro-acoustic transducer comprising a vibration electrode (23) and stationary electrodes (21, 21') which consist of electret devices and which are formed at both sides of said vibration electrode (23) at a distance therefrom, said electret devices comprising electret films (24, 24') having metal layers (25, 25', 26, 26') thereon.
Claim 6
Dependent Claim
52 words
A condenser type electro-acoustic transducer comprising a vibration electrode (23) and stationary electrodes (21, 21') which consist of electret devices and which are formed at both sides of said vibration electrode (23) at a distance therefrom, said electret devices comprising electret films (24, 24') having metal layers (25, 25', 26, 26') thereon.
Claim 7
Dependent Claim
42 words
A condenser type clectro-acoustic transducer according to claim 4, wherein said electret device is obtained by forming into an electret a laminated body of a dielectric material film (24, 24') having metal layers (25, 25', 26, 26') formed on both surfaces thereof.
Claim 8
Dependent Claim
28 words
A consenser type electro-acoustic transducer according to claim 4, wherein said metal layers (25, 25') opposing said vibration electrode (23) have terminals (27, 27') for applying the voltage.
References Cited (Backward Citations)
No citation records indexed.
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