Patent US4192977A successfully refreshed from Google Patents.
US4192977A
Expired / Lapsed
US
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Highly directional ultrasonic electret transducer
Assignee: AKG Acoustics GmbH
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Filing: 1977-12-16
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Granted: 1980-03-11
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Expires: 1997-12-16
Abstract
Abstract An ultrasonic converter having a single side, focused, substantially secondary radiation free directional characteristic, comprises an exponential horn-like directional element and a capacitative transducer with an electret diaphragm. A pre-staged resonator aids in controlling the directional characteristic. The capacitive transducer has an approximately bell-shaped curvature-like diaphragm velocity distribution which tapers off toward the diaphragm edge to improve the focusing which is achieved by employing a non-uniform charge across the surface of the electret diaphragm tapering off toward its edge and a backplate arrangement which supports the diaphragm at a plurality of selected points with a selected dimensioning of singular volumes behind the counter-electrode bores.
Inventors
- 👤 Kurt Stamm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:46
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/32; G; G01; G01H; G01H11/00; G01H11/06; G10; G10K; G10K11/00; G10K11/18; G10K11/26; G10K11/28; H04R19/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
131 words
An ultrasonic converter having single side, focused, substantially secondary radiation free directional characterstic, comprising a horn-like directional element with an inner end and an outer opened end and walls extending outwardly toward the outer opened end preferably according to an exponential function, a capacitive transducer located in said horn-like directional element adjacent to and closing off its inner end and having an electret diaphragm facing toward the outer end of said horn-like element with a diaphragm edge, said diaphragm including means for producing an approximately bell curved velocity distribution thereon tapering off toward the diaphragm edge, said means for producing an approximately bell-curved velocity distribution comprising a distribution of the electret charge on said diaphragm corresonding to an approximately bell-curved diaphragm velocity distribution tapering off toward the edge of the diaphragm.
Claim 2
Dependent Claim
131 words
An ultrasonic converter having single side, focused, substantially secondary radiation free directional characterstic, comprising a horn-like directional element with an inner end and an outer opened end and walls extending outwardly toward the outer opened end preferably according to an exponential function, a capacitive transducer located in said horn-like directional element adjacent to and closing off its inner end and having an electret diaphragm facing toward the outer end of said horn-like element with a diaphragm edge, said diaphragm including means for producing an approximately bell curved velocity distribution thereon tapering off toward the diaphragm edge, said means for producing an approximately bell-curved velocity distribution comprising a distribution of the electret charge on said diaphragm corresonding to an approximately bell-curved diaphragm velocity distribution tapering off toward the edge of the diaphragm.
Claim 3
Dependent Claim
36 words
An ultrasonic converter, as claimed in claim 1, wherein said electret diaphragm includes a housing having a periphery substantially filling the inner end of said horn-like directional element to close this end of the directional element.
Claim 4
Dependent Claim
33 words
An ultrasonic converter, as claimed in claim 2, including a resonator arrangement arranged between said converter diaphragm and the open end of said horn-like directional element to increase directional characteristic of the converter.
Claim 5
Dependent Claim
18 words
An ultrasonic converter, as claimed in claim 3, wherein said resonator arrangement comprises a perforated slightly curved disc.
Claim 6
Dependent Claim
135 words
An ultrasonic converter having a single side, focused, substantially directional characteristic free from secondary maxima, comprising a tubular horn-like element having a tubular wall with an inner end and an outer open end and a wall between said outer and inner ends tapering outwardly to said outer end in a curve according to an exponential function, an electret converter in said horn-like element adjacent said inner end and having a housing with a diaphragm on a side of said housing facing toward said outer end, a diaphragm support member in said housing behind said diaphragm with a support face having projecting portions and hollow portions between the projecting portions, a counterelectrode disc having an inner face engaged on said support projecting portions and having an outer face with electrode disc projections urged against said diaphragm.
Claim 7
Dependent Claim
135 words
An ultrasonic converter having a single side, focused, substantially directional characteristic free from secondary maxima, comprising a tubular horn-like element having a tubular wall with an inner end and an outer open end and a wall between said outer and inner ends tapering outwardly to said outer end in a curve according to an exponential function, an electret converter in said horn-like element adjacent said inner end and having a housing with a diaphragm on a side of said housing facing toward said outer end, a diaphragm support member in said housing behind said diaphragm with a support face having projecting portions and hollow portions between the projecting portions, a counterelectrode disc having an inner face engaged on said support projecting portions and having an outer face with electrode disc projections urged against said diaphragm.
Claim 8
Dependent Claim
38 words
A ultrasonic converter, as claimed in claim 5, including a resonator disc disposed between said diaphragm and the open end of said horn-like element and having a curved perforated surface to increase the directional characteristic of the converter.
Claim 9
Dependent Claim
24 words
An ultrasonic converter according to claim 5 wherein said diaphragm has a charged distribution following a bell shaped curve decreasing toward the diaphragm edge.
References Cited (Backward Citations)
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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) | 1983-03-11 | 1983-09-10 | 1984-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-11 | 1987-09-10 | 1988-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-11 | 1991-09-10 | 1992-03-11 | $7700.00 | Window Closed / Lapsed |