US4641377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoacoustic speaker and method
Assignee: Gas Technology Institute
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Filing: 1984-04-06
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Granted: 1987-02-03
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Expires: 2004-04-06
Abstract
Abstract A photoacoustic speaker and method for producing photoacoustic sound by utilizing a laser beam, modulating the intensity of the laser beam in response to audio signal inputs and passing the modulated laser beam into a gas absorption chamber wherein gas capable of absorption of the modulated laser beam upon such absorption produces photothermic pressure waves corresponding to the audio signal inputs and which produce sound upon impingement on walls of the absorption chamber. The photoacoustic speaker achieves high fidelity sound reproduction and is capable of projecting a column of sound thereby providing an acoustic dimension effect.
Inventors
- 👤 William F. Rush
- 👤 James E. Huebler
- 👤 Peter Lysenko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:23
CPC Classifications
H; H04; H04R; H04R23/00; H04R23/008
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
116 words
A photoacoustic speaker comprising a laser beam source means, a modulating means capable of modulating the intensity of said laser beam in response to audio signal inputs producing a corresponding modulated laser beam, and an elongated sealed gas absorption chamber having a laser transparent window in one end in the path of said laser beam, a rigid end opposite to said window, said gas absorption chamber having elongated thin flexible side walls, said two ends and said flexible side walls confining gas capable of absorption of said modulated laser beam thereby producing pressure waves which impinge on said elongated flexible side walls of said chamber to produce sound and transmit said sound exterior to said chamber.
Claim 2
Dependent Claim
116 words
A photoacoustic speaker comprising a laser beam source means, a modulating means capable of modulating the intensity of said laser beam in response to audio signal inputs producing a corresponding modulated laser beam, and an elongated sealed gas absorption chamber having a laser transparent window in one end in the path of said laser beam, a rigid end opposite to said window, said gas absorption chamber having elongated thin flexible side walls, said two ends and said flexible side walls confining gas capable of absorption of said modulated laser beam thereby producing pressure waves which impinge on said elongated flexible side walls of said chamber to produce sound and transmit said sound exterior to said chamber.
Claim 3
Dependent Claim
19 words
A photoacoustic speaker according to claim 1 wherein said laser beam modulating means is a laser cavity length transducer.
Claim 4
Dependent Claim
18 words
A photoacoustic speaker according to claim 1 wherein said laser beam modulating means is an electrooptical beam modulator.
Claim 5
Dependent Claim
18 words
A photoacoustic speaker according to claim 1 wherein said laser beam modulating means is a mechanical beam chopper.
Claim 6
Dependent Claim
35 words
A photoacoustic speaker according to claim 1 wherein said laser beam passes through a beam expander before entering said gas absorption chamber, said beam expander capable of sizing the expanded beam to said absorption chamber.
Claim 7
Dependent Claim
21 words
A photoacoustic speaker according to claim 5 wherein said laser beam passes through said beam expander prior to said modulating means.
Claim 8
Dependent Claim
35 words
A photoacoustic speaker according to claim 1 wherein said laser beam passes through a beam contractor before entering said gas absorption chamber, said beam contractor capable of sizing the contracted beam to said absorption chamber.
Claim 9
Dependent Claim
21 words
A photoacoustic speaker according to claim 7 wherein said laser beam passes through said beam contractor prior to said modulating means.
Claim 10
Dependent Claim
13 words
A photoacoustic speaker according to claim 1 wherein said absorbing gas comprises air.
Claim 11
Dependent Claim
23 words
A photoacoustic speaker according to claim 1 wherein said absorbing gas comprises a gas having high absorption capability for said modulated laser beam.
Claim 12
Dependent Claim
31 words
A photoacoustic speaker according to claim 1 wherein said absorption chamber length is about one-half to three-quarters the distance required for substantially complete absorption of energy of said modulated laser beam.
Claim 13
Dependent Claim
27 words
A photoacoustic speaker according to claim 1 wherein the length of said elongated absorption chamber is more than five times greater than the diameter of said chamber.
Claim 14
Dependent Claim
29 words
A photoacoustic speaker according to claim 1 wherein said length of said elongated absorption chamber is about 10 to about 20 times greater than said diameter of said chamber.
Claim 15
Dependent Claim
27 words
A photoacoustic speaker according to claim 1 wherein said gas is maintained in said gas absorption chamber at a pressure of about 0.6 to about 1.4 atmospheres.
Claim 16
Dependent Claim
141 words
A photoacoustic speaker comprising: a laser beam source means, a modulating means capable of modulating the intensity of said laser beam in response to audio signal inputs producing a corresponding modulated laser beam, and an elongated sealed gas containment chamber serving as a gas absorption chamber in the path of said laser beam, said gas absorption chamber comprising a laser transparent window at one end which permits said laser beam to enter said gas absorption chamber, a rigid end at the opposite end fixed parallel to said window, and thin walls of a flexible material gastightly joined to said window and said rigid end, said gas absorption chamber confining gas capable of absorption of said modulated laser beam thereby producing pressure waves which impinge on said walls of said chamber to produce sound and transmit said sound exterior to said chamber.
Claim 17
Dependent Claim
141 words
A photoacoustic speaker comprising: a laser beam source means, a modulating means capable of modulating the intensity of said laser beam in response to audio signal inputs producing a corresponding modulated laser beam, and an elongated sealed gas containment chamber serving as a gas absorption chamber in the path of said laser beam, said gas absorption chamber comprising a laser transparent window at one end which permits said laser beam to enter said gas absorption chamber, a rigid end at the opposite end fixed parallel to said window, and thin walls of a flexible material gastightly joined to said window and said rigid end, said gas absorption chamber confining gas capable of absorption of said modulated laser beam thereby producing pressure waves which impinge on said walls of said chamber to produce sound and transmit said sound exterior to said chamber.
Claim 18
Dependent Claim
23 words
A photoacoustic speaker according to claim 15 wherein said rigid end of said gas absorption chamber is coated with a laser reflective material.
Claim 19
Dependent Claim
24 words
A photoacoustic speaker according to claim 15 wherein said flexible material is selected from a group of membranes consisting of elastic latex and aluminum.
Claim 20
Independent Claim
111 words
A method for producing photoacoustic sound comprising: producing a laser beam, modulating the intensity of said laser beam in proportion to audio signal inputs; passing the modulated laser beam through a laser transparent window in one end of an elongated sealed gas absorption chamber having thin flexible side walls and through the length of said elongated chamber to an opposite rigid end, said laser beam not striking said flexible side walls; absorbing radiation of said modulated laser beam by gas confined in said elongated chamber thereby producing photothermic pressure waves which produce sound and transmit said sound exterior of said chamber upon impingement on said side walls of said absorption chamber.
Claim 21
Independent Claim
111 words
A method for producing photoacoustic sound comprising: producing a laser beam, modulating the intensity of said laser beam in proportion to audio signal inputs; passing the modulated laser beam through a laser transparent window in one end of an elongated sealed gas absorption chamber having thin flexible side walls and through the length of said elongated chamber to an opposite rigid end, said laser beam not striking said flexible side walls; absorbing radiation of said modulated laser beam by gas confined in said elongated chamber thereby producing photothermic pressure waves which produce sound and transmit said sound exterior of said chamber upon impingement on said side walls of said absorption chamber.
Claim 22
Independent Claim
129 words
A method for producing photoacoustic sound comprising: producing a laser beam, and modulating the intensity of said laser beam in proportion to audio signal inputs; passing the modulated laser beam through a laser transparent window into an elongated sealed gas containment chamber serving as a gas absorption chamber having thin, flexible side walls and confining gas capable of absorption of said modulated laser beam, and passing a portion of said modulated laser beam to the opposite end of said absorption chamber, said modulated laser beam striking a laser reflective material reflecting said laser in reverse direction through said elongated chamber for further absorption, and thereby producing photothermic pressure waves which produce sound and transmit said sound exterior to said chamber upon impingement on said walls of said absorption chamber.
Claim 23
Independent Claim
129 words
A method for producing photoacoustic sound comprising: producing a laser beam, and modulating the intensity of said laser beam in proportion to audio signal inputs; passing the modulated laser beam through a laser transparent window into an elongated sealed gas containment chamber serving as a gas absorption chamber having thin, flexible side walls and confining gas capable of absorption of said modulated laser beam, and passing a portion of said modulated laser beam to the opposite end of said absorption chamber, said modulated laser beam striking a laser reflective material reflecting said laser in reverse direction through said elongated chamber for further absorption, and thereby producing photothermic pressure waves which produce sound and transmit said sound exterior to said chamber upon impingement on said walls of said absorption chamber.
Claim 24
Dependent Claim
16 words
The method of claim 19 comprising the step of expanding laser beam prior to said modulating.
Claim 25
Independent Claim
100 words
A method for producing photoacoustic sound comprising: producing a laser beam, and modulating the intensity of said laser beam in proportion to audio signal inputs; passing the modulated laser beam through a laser transparent window into an elongated sealed gas containment chamber serving as a gas absorption chamber having thin, flexible side walls and confining gas capable of absorption of said modulated laser beam, thereby producing photothermic pressure waves which produce sound and transmit said sound exterior to said chamber upon impingement on said walls of said absorption chamber to project a column of sound providing an acoustic dimension effect.
Claim 26
Independent Claim
100 words
A method for producing photoacoustic sound comprising: producing a laser beam, and modulating the intensity of said laser beam in proportion to audio signal inputs; passing the modulated laser beam through a laser transparent window into an elongated sealed gas containment chamber serving as a gas absorption chamber having thin, flexible side walls and confining gas capable of absorption of said modulated laser beam, thereby producing photothermic pressure waves which produce sound and transmit said sound exterior to said chamber upon impingement on said walls of said absorption chamber to project a column of sound providing an acoustic dimension effect.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-02-02 | 1990-08-04 | 1991-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-02 | 1994-08-04 | 1995-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-02 | 1998-08-04 | 1999-02-03 | $7700.00 | Window Closed / Lapsed |