Patent US4922471A successfully refreshed from Google Patents.
US4922471A
Expired / Lapsed
US
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Capacitive sound transducer
Assignee: Sennheiser Electronic GmbH and Co KG
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Filing: 1989-03-06
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Granted: 1990-05-01
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Expires: 2009-03-06
Abstract
Abstract Capacitive sound transducer of a very small construction, in particular a microphone has at least two joint semiconductor chips, which embody a membrane unit and a fixed counter-electrode structure. The acoustic active portion of the membrane unit 1 with at least one counter-electrode structure 3, which is separated from the membrane unit by means of an air gap, forms a system which is comparable to a field effect transistor. The membrane unit which is formed of a semiconducting ground material encompasses an acoustically active membrane surface (2), one side 5 of which confronts the counter-electrode structure is electrically conductive. The counter-electrode structure 3 has a semiconductive base material out of which there is machined a channel length which has been limited by a source-drain arrangement, the geometric width measurrement of which is on the order of magnitude of a tenth of the lateral measurement of the active membrane surface.
Inventors
- 👤 Wolfgang Kuehnel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:01
CPC Classifications
H; H04; H04R; H04R19/00; H04R19/005; Y; Y10; Y10T; Y10T29/00; Y10T29/43; Y10T29/435
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
164 words
Capacitive sound transducer comprising a first and a second semiconductor chip, the first semiconductor chip comprising a membrane unit and the second semiconductor chip comprising a counter-electrode structure, the first semiconductor chip being affixed to the second semiconductor chip; an acoustic active portion of the membrane unit being separated from the counter-electrode structure by means of an air gap; said membrane unit comprising semiconductive ground material and said acoustic active portion of said membrane unit having an electrically conductive surface confronting said counter-electrode structure; said counter-electrode structure comprising a channel defining a source-drain arrangement operating according to field effect principle, whereby said acoustic active portion of the membrane unit and said counter-electrode structure form a sound transducer system; said channel having a geometric width measurement and said acoustic active portion of said membrane unit having a geometric width, the width of the channel being on the order of magnitude of a tenth of the width of the acoustic active portion of the membrane unit.
Claim 2
Dependent Claim
164 words
Capacitive sound transducer comprising a first and a second semiconductor chip, the first semiconductor chip comprising a membrane unit and the second semiconductor chip comprising a counter-electrode structure, the first semiconductor chip being affixed to the second semiconductor chip; an acoustic active portion of the membrane unit being separated from the counter-electrode structure by means of an air gap; said membrane unit comprising semiconductive ground material and said acoustic active portion of said membrane unit having an electrically conductive surface confronting said counter-electrode structure; said counter-electrode structure comprising a channel defining a source-drain arrangement operating according to field effect principle, whereby said acoustic active portion of the membrane unit and said counter-electrode structure form a sound transducer system; said channel having a geometric width measurement and said acoustic active portion of said membrane unit having a geometric width, the width of the channel being on the order of magnitude of a tenth of the width of the acoustic active portion of the membrane unit.
Claim 3
Dependent Claim
50 words
Capacitive sound transducer as claimed in claim 1, wherein ground material for the membrane unit and the counter-electrode structure comprises silicon; and the active surface of the membrane unit consists of a silicon nitrate-layer, which is vaporized with aluminum and a mechanical tension of which is determined by ion implantation.
Claim 4
Dependent Claim
22 words
Capacitive sound transducer as claimed in claim 1 wherein said channel of said counter-electrode structure operates accorting to FET channel enriching principle.
Claim 5
Dependent Claim
22 words
Capacitive sound transducer as claimed in claim 1 wherein said channel of said counter-electrode structure operates accorting to FET channel depletion principle.
Claim 6
Dependent Claim
22 words
Capacitive sound transducer as claimed in claim 1 wherein said counter-electrode structure contains an enclosed volume thereby effecting a pressure transducer characteristic.
Claim 7
Dependent Claim
22 words
Capacitive transducer as claimed in claim 1 wherein said counter-electrode contains a substantially enclosed volume with openings effecting a pressure gradient characteristic.
References Cited (Backward Citations)
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US4558184A
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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) | 1993-04-30 | 1993-10-30 | 1994-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-30 | 1997-10-30 | 1998-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-30 | 2001-10-30 | 2002-05-01 | $7700.00 | Window Closed / Lapsed |