Electret assembly
First Claim
1. An electret assembly for an electroacoustic transducer comprising:
- a thin, flexible, planar diaphragm comprising a first electrode of an electret assembly;
a planar backplate comprising a second electrode of the electret assembly;
one of the first and second electrodes of the assembly being charged to a given differential voltage relative to the other electrode;
and diaphragm mounting means for mounting the diaphragm in fixed, spaced, substantially parallel relation to the backplate, the differential voltage tending to pull a central portion of the diaphragm toward the backplate, thereby tensioning and stiffening the central portion of the diaphragm;
the diaphragm mounting means permitting limited radial movement of the rim of the diaphragm in the plane of the diaphragm but precluding movement of the rim of the diaphragm perpendicular to the plane of the diaphragm.
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Accused Products
Abstract
A tiny electret assembly for an electroacoustic hearing aid transducer, either a microphone or a sound reproducer, includes a thin, flexible, planar diaphragm and a planar backplate, the diaphragm and the backplate constituting the electret electrodes. One of the two electrodes is permanently charged to a given differential voltage relative to the other and the two electrodes are mounted, in the transducer, in fixed, spaced, substantially parallel relation to each other; the differential voltage between the electrodes pulls a central portion of the diaphragm toward the backplate, tensioning and stiffening the diaphragm. The mount for the diaphragm permits movement of the diaphragm rim in the plane of the diaphragm but precludes movement of the rim of the diaphragm perpendicular to the plane of the diaphragm (and the backplate) so that the diaphragm cannot buckle. Different rim mounts for the diaphragm are described.
65 Citations
11 Claims
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1. An electret assembly for an electroacoustic transducer comprising:
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a thin, flexible, planar diaphragm comprising a first electrode of an electret assembly; a planar backplate comprising a second electrode of the electret assembly; one of the first and second electrodes of the assembly being charged to a given differential voltage relative to the other electrode; and diaphragm mounting means for mounting the diaphragm in fixed, spaced, substantially parallel relation to the backplate, the differential voltage tending to pull a central portion of the diaphragm toward the backplate, thereby tensioning and stiffening the central portion of the diaphragm; the diaphragm mounting means permitting limited radial movement of the rim of the diaphragm in the plane of the diaphragm but precluding movement of the rim of the diaphragm perpendicular to the plane of the diaphragm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification