US3778562A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic loudspeaker having acoustic wavefront modifying device
Assignee: DAYTON WRIGHT GROUP Ltd
•
Filing: 1973-10-21
•
Granted: 1973-12-11
•
Expires: 1993-10-21
Abstract
Abstract An Acoustic Wavefront Modifying Device can be used with acoustic waves having audio frequencies within the range of human hearing as a lens or prism. The device comprises an enclosure having at least a portion of its surface space acoustically transparent and having therein a gas in which the speed of sound differs from the speed of sound in the ambient gas. The device is most particularly embodied in an electrostatic loudspeaker having one or a plurality of electrostatic transducer units within a gas enclosure and having acoustically transparent front and back surfaces. The gas is usually sulphurhexafluoride or perfluoropropane or a mixture of them or either of them with air.
Inventors
- 👤 W Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:05
CPC Classifications
H; H04; H04R; H04R19/00; H04R19/02; H04R1/00; H04R1/42
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
173 words
An acoustic wavefront modifying device comprising: an enclosure having at least one substantially planar and acoustically transparent portion of the surface thereof; electrostatic acoustic transducer means within said enclosure and adapted to propagate acoustic waves and to transmit them to one side of said planar and acoustically transparent portion of said enclosure; said electrostatic acoustic transducer means having at least two substantially planar working areas arranged in said enclosure each at an angle to said substantially planar and acoustically transparent surface portion of said enclosure and at an angle to each other; said enclosure having a gas therein in which the speed of sound differs from the speed of sound in the gas external to said enclosure; so that said acoustic waves transmitted to the one side of said planar and acoustically transparent portion of said enclosure and past the substantially acoustically transparent material thereof, are subject to wavefront refraction in accordance with the refractive index determined by the ratio of speeds of sound in said gases within and external to said enclosure.
Claim 2
Dependent Claim
173 words
An acoustic wavefront modifying device comprising: an enclosure having at least one substantially planar and acoustically transparent portion of the surface thereof; electrostatic acoustic transducer means within said enclosure and adapted to propagate acoustic waves and to transmit them to one side of said planar and acoustically transparent portion of said enclosure; said electrostatic acoustic transducer means having at least two substantially planar working areas arranged in said enclosure each at an angle to said substantially planar and acoustically transparent surface portion of said enclosure and at an angle to each other; said enclosure having a gas therein in which the speed of sound differs from the speed of sound in the gas external to said enclosure; so that said acoustic waves transmitted to the one side of said planar and acoustically transparent portion of said enclosure and past the substantially acoustically transparent material thereof, are subject to wavefront refraction in accordance with the refractive index determined by the ratio of speeds of sound in said gases within and external to said enclosure.
Claim 3
Dependent Claim
56 words
The acoustic wavefront modifying device of claim 1, wherein said enclosure is hermetically sealed, and the gas external of said enclosure is air; and where the gas within said enclosure has a lower speed of sound than that of air, is more dense than air, and has a higher electrical breakdown voltage than that of air.
Claim 4
Dependent Claim
28 words
The acoustic wavefront modifying device of claim 1, wherein said enclosure is hermetically sealed and is connected for gas flow with a further enclosure having said gas therein.
Claim 5
Dependent Claim
23 words
The acoustic wavefront modifying device of claim 3, further including pressure and gas flow regulating means between said enclosure and said further enclosure.
Claim 6
Dependent Claim
31 words
The acoustic wavefront modifying device of Claim 2, where said at least one substantially planar and acoustically transparent portion of the surface of said enclosure comprises a membrane of plastic material.
Claim 7
Dependent Claim
30 words
The acoustic wavefront modifying device of claim 2, comprising two opposed substantially acoustically transparent portions of the surface of said enclosure, each said portion comprising a membrane of plastic material.
Claim 8
Dependent Claim
38 words
The acoustic wavefront modifying device of claim 6, where one of said membranes of plastic material is curved so as to give a lens effect with respect to the acoustic waves being transmitted thereto and past said material.
Claim 9
Dependent Claim
33 words
The acoustic wavefront modifying device of claim 1 where said gas is chosen from the group consisting of sulphur hexafluoride, perfluoropropane, perfluoropropane/sulphur hexafluoride mixture, air/sulphur hexafluoride mixture, air/perfluoropropane mixture and air/perfluoropropane/sulphur hexafluoride mixture.
Claim 10
Dependent Claim
163 words
An electrostatic loudspeaker comprising at least two push-pull electrostatic acoustic transducer units and an hermetically sealed, gas filled enclosure, wherein: each of said at least two push-pull electrostatic acoustic transducer units comprises a substantially planar diaphragm having a high-resistivity coating over at least a major portion thereof, situated between a pair of substantially rigid, electrically conductive electrodes, each said electrostatic transducer unit being electrically connected to a direct current high voltage source and to an audio frequency voltage source; said enclosUre having at least one substantially planar and acoustically transparent diaphragm means in a portion of the surface thereof, and being filled with a gas having a speed of sound transmission characteristic, at least in the audio range, different than that of air; said substantially planar diaphragms of said at least two push-pull electrostatic acoustic transducers are arranged each at an angle to said substantially planar and acoustically transparent portion of the surface of said enclosure and at an angle to each other.
Claim 11
Dependent Claim
163 words
An electrostatic loudspeaker comprising at least two push-pull electrostatic acoustic transducer units and an hermetically sealed, gas filled enclosure, wherein: each of said at least two push-pull electrostatic acoustic transducer units comprises a substantially planar diaphragm having a high-resistivity coating over at least a major portion thereof, situated between a pair of substantially rigid, electrically conductive electrodes, each said electrostatic transducer unit being electrically connected to a direct current high voltage source and to an audio frequency voltage source; said enclosUre having at least one substantially planar and acoustically transparent diaphragm means in a portion of the surface thereof, and being filled with a gas having a speed of sound transmission characteristic, at least in the audio range, different than that of air; said substantially planar diaphragms of said at least two push-pull electrostatic acoustic transducers are arranged each at an angle to said substantially planar and acoustically transparent portion of the surface of said enclosure and at an angle to each other.
Claim 12
Dependent Claim
79 words
The electrostatic loudspeaker of claim 9 where said enclosure comprises a pair of opposed diaphragms of substantially acoustically transparent plastic material, and said at least two electrostatic transducer units are secured within an hermetically sealed enclosure at least partially defined by said pair of opposed diaphragms; and where the gas within said enclosure has a lower speed of sound than that of air, is more dense than air, and has a higher electrical breakdown voltage than that of air.
Claim 13
Dependent Claim
47 words
The electrostatic loudspeaker of claim 9, where not less than one of the at least two electrostatic transducer units are electrically connected to said audio frequency voltage source so as to have impressed thereon the total frequency range of the output of said audio frequency voltage source.
Claim 14
Dependent Claim
43 words
The electrostatic loudspeaker of claim 11, where at least one of said electrostatic transducer units is electrically connected to said audio frequency voltage source so as to have impressed thereon a limited frequency range of the output of said audio frequency voltage source.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |