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US 4,070,741 AGranted
Method of making an electret acoustic transducer
AssigneeGenRad, Inc.
InventorSvetislav V. Djuric
Life of this patent
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Abstract
In the method of construction disclosed herein, posts for supporting the condenser transducer diaphragm in relation to a backplate are formed on the diaphragm film itself by selectively etching away a photoresist material laminated to the film. The electret material is then supported on the backplate rather than being carried by the diaphragm.
Claims7
The method of making an electret acoustic transducer comprising:
- laminating an elastic diaphragmatic plastic film with a layer of material of predetermined thickness;
- selectively removing undesired portions of said layer of material, leaving a desired post pattern on the film;
- metalizing the post side of said film to render it conductive;
- securing said film to a supporting ring;
- providing a conductive backplate carrying on one face thereof a layer of polarized electret material which is itself insulating;
- mounting said backplate and said ring in juxtaposition in a transducer assembly with said post pattern contacting the electret layer, the diaphragmatic film being deformed and spaced from the backplate thereby.
3 more elements
The method of making an electret acoustic transducer comprising:
- laminating an elastic diaphragmatic plastic film with a photoresist material;
- exposing said material in a pattern corresponding to a desired post pattern for supporting a diaphragm in the transducer;
- removing the undesired portion of said material, leaving the desired post pattern on the film;
- metalizing the post side of said film to render it conductive;
- securing said film to a supporting ring;
- providing a conductive backplate carrying on one face thereof a layer of polarized electret material which is itself insulating;
- mounting said backplate and said ring in juxtaposition in a transducer assembly with said post pattern contacting the electret layer, the diaphragmatic film being deformed and spaced from the backplate thereby.
4 more elements
The method of making an electret acoustic transducer comprising:
- vacuum depositing a thin copper layer over a plastic film and laminating it with a photosensitive polymer resist;
- exposing said resist in a pattern corresponding to a desired post pattern for supporting a diaphragm in the transducer;
- removing the undesired portion of said resist, leaving resist in the desired post pattern on the film;
- metalizing the post side of said film to render it conductive;
- securing said film to a supporting ring;
- providing a conductive backplate carrying on one face thereof a layer of polarized Teflon electret material;
- mounting said backplate and said ring in juxtaposition in a transducer assembly with said post pattern contacting the electret layer, the diaphragmatic film being spaced from the backplate thereby.
4 more elements
Dependencies are inferred from the claim text.