US3611277A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensitive hydrophone
Assignee: United States Department of the Navy
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Filing: 1969-04-30
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Granted: 1971-10-05
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Expires: 1989-04-30
Abstract
Abstract An optically interrogated acoustic ASW surveillance system is disclosed in which a laser beam is used to illuminate floating acoustic transducers. These transducers have beam-splitting optics and a submerged monocrystalline diaphragm which modulates one portion of the split beam in response to acoustic signals arriving through the water. When this portion of the beam is colinearly recombined with the unmodulated portion of the split beam, an amplitude-modulated light signal is produced which is directed back to and detected at the laser source.
Inventors
- 👤 Max N Yoder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:25
CPC Classifications
G; G01; G01H; G01H9/00; G01S; G01S1/00; G01S1/72
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
167 words
Apparatus for detecting acoustic signals propagating beneath the surface of a fluid medium comprising: a housing adapted to float at the surface of said fluid mediUm; an acoustic signal detector positioned in said housing with its sensing element in communication with said fluid medium; an optical system accommodated within said housing and adapted to be illuminated with a laser beam, said optical system including means for directing a portion of said laser beam over a first optical path of fixed length and thereafter redirecting said portion back along the path of said laser beam and for directing another portion of said beam over a second optical path whose length varies in response to the amplitude of any acoustic signal detected by said sensing element and thereafter redirecting said last-mentioned portion back along the path of said laser beam such that both redirected portions of said beam interact because of their colinear orientation to produce a modulated return beam whenever acoustic energy is detected by said sensing element.
Claim 2
Dependent Claim
167 words
Apparatus for detecting acoustic signals propagating beneath the surface of a fluid medium comprising: a housing adapted to float at the surface of said fluid mediUm; an acoustic signal detector positioned in said housing with its sensing element in communication with said fluid medium; an optical system accommodated within said housing and adapted to be illuminated with a laser beam, said optical system including means for directing a portion of said laser beam over a first optical path of fixed length and thereafter redirecting said portion back along the path of said laser beam and for directing another portion of said beam over a second optical path whose length varies in response to the amplitude of any acoustic signal detected by said sensing element and thereafter redirecting said last-mentioned portion back along the path of said laser beam such that both redirected portions of said beam interact because of their colinear orientation to produce a modulated return beam whenever acoustic energy is detected by said sensing element.
Claim 3
Dependent Claim
184 words
Apparatus for detecting acoustic signals present in a fluid medium comprising, in combination, a housing adapted to float at the free surface of said fluid medium; an acoustic signal detector accommodated within said housing with its sensing element adapted to receive acoustic signals present in the surrounding fluid medium, said sensing element having one surface thereof which is light reflecting and which is displaced in accordance with the amplitude of said received acoustic signals; a wide-angle lens supported by said housing at a location which is above the free surface of said fluid medium, said wide-angle lens when illuminated with a monochromatic beam of light originating at a remote laser focusing said beam on said light reflective surface; and optical means accommodated within said housing for directing a portion of said beam over a path of a predetermined fixed length and for thereafter combining said portion with the light beam reflected from said reflecting surface, the resulting beam having an amplitude which varies in accordance with the detected acoustic signals, this resulting beam thereafter proceeding through said wide-angle lens toward a remote detecting location.
Claim 4
Dependent Claim
184 words
Apparatus for detecting acoustic signals present in a fluid medium comprising, in combination, a housing adapted to float at the free surface of said fluid medium; an acoustic signal detector accommodated within said housing with its sensing element adapted to receive acoustic signals present in the surrounding fluid medium, said sensing element having one surface thereof which is light reflecting and which is displaced in accordance with the amplitude of said received acoustic signals; a wide-angle lens supported by said housing at a location which is above the free surface of said fluid medium, said wide-angle lens when illuminated with a monochromatic beam of light originating at a remote laser focusing said beam on said light reflective surface; and optical means accommodated within said housing for directing a portion of said beam over a path of a predetermined fixed length and for thereafter combining said portion with the light beam reflected from said reflecting surface, the resulting beam having an amplitude which varies in accordance with the detected acoustic signals, this resulting beam thereafter proceeding through said wide-angle lens toward a remote detecting location.
Claim 5
Independent Claim
195 words
A system for detecting at a remote location acoustic signals propagating beneath the surface of a fluid medium comprising, in combination, a housing floating on the surface of said fluid medium; an acoustic signal detector accommodated within said floating housing with its sensing element adapted to receive acoustic signals present in the surrounding fluid medium; a laser located at said remote location and adapted to illuminate an exposed area of said housing with a monochromatic beam of light; means within said housing for splitting said monochromatic beam of light and for directing one portion thereof over a first optical path which is of a fixed length and for directing another portion thereof over a second path whose length varies in accordance with the magnitude of any acoustic signals detected by said signal acoustic detector, said last-mentioned means also operating to thereafter recombine said portions of said split beam and to redirect the beam resulting therefrom back towards said remote location; and means at said remote location for detecting any amplitude modulation of the returning beam thereby to ascertain the nature of any acoustic signals propagating in said fluid medium in the vicinity of said housing.
Claim 6
Independent Claim
195 words
A system for detecting at a remote location acoustic signals propagating beneath the surface of a fluid medium comprising, in combination, a housing floating on the surface of said fluid medium; an acoustic signal detector accommodated within said floating housing with its sensing element adapted to receive acoustic signals present in the surrounding fluid medium; a laser located at said remote location and adapted to illuminate an exposed area of said housing with a monochromatic beam of light; means within said housing for splitting said monochromatic beam of light and for directing one portion thereof over a first optical path which is of a fixed length and for directing another portion thereof over a second path whose length varies in accordance with the magnitude of any acoustic signals detected by said signal acoustic detector, said last-mentioned means also operating to thereafter recombine said portions of said split beam and to redirect the beam resulting therefrom back towards said remote location; and means at said remote location for detecting any amplitude modulation of the returning beam thereby to ascertain the nature of any acoustic signals propagating in said fluid medium in the vicinity of said housing.
Claim 7
Dependent Claim
26 words
In an arrangement as defined in claim 3 wherein said acoustic signal detector includes a thin, monocrystalline diaphragm with one planar surface thereof reflective to light.
Claim 8
Dependent Claim
34 words
In an arrangement as defined in claim 3 wherein a wide-angle lens is mounted on an exposed surface of said housing so as to focus any incoming light into the interior of said housing.
References Cited (Backward Citations)
US3175088A
Cited
US3373401A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |