Communications – electrical: acoustic wave systems and devices – Signal transducers – Underwater type
Reexamination Certificate
1999-05-10
2001-02-13
Lobo, Ian J. (Department: 3662)
Communications, electrical: acoustic wave systems and devices
Signal transducers
Underwater type
Reexamination Certificate
active
06188644
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates generally to transducers used to convert an acoustic signal to an electrical signal, and more particularly to a transducer using scattered laser light reflections from a pressure release boundary between two mediums of different acoustic characteristic impedance.
(2) Description of the Prior Art
Traditional transducers rely on piezoelectric materials to convert acoustic signals in the form of pressure waves into electrical signals. More recently, research and development has been undertaken in the area of laser optic transducers, or hydrophones. As an example of such a device, U.S. Pat. No. 5,504,719 to Jacobs recites a laser beam which is focused upon a small volume of water in which natural light scattering matter is suspended and which matter vibrates in synchronism with any sonic waves present. The vibration produces a phase modulation of the scattered light which may be recovered by optical heterodyne and sensitive phase detection techniques. These laser transducers suffer in that the particles scatter the laser light in all directions, thus significantly reducing the amount of scattered light reflected back to the transducer and making detection of an acoustic signal more difficult. When the flow around the transducer is increased, additional noise components are introduced further complicating signal detection.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a laser based technique for detecting acoustic signals in a fluid such as in an underwater environment.
Another object of the present invention is to provide a laser based technique for detecting acoustic signals in a dynamic underwater environment.
Still another object of the present invention is to provide a laser based technique for detecting acoustic signals in an underwater environment which increases the amount of reflected light.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, a laser-based Doppler interferometer system, or photon transducer system, is provided which interrogates a pressure release surface with a beam of coherent laser radiation. The pressure release surface is formed by generating a gas pocket in the fluid, creating a boundary layer between the laser light source, which is located within the gas pocket, and the surrounding fluid. Laser light is reflected from the boundary and is detected by the interferometer to obtain the Doppler velocity of the pressure release surface. The pressure incident on the boundary can be determined from the measured velocity, providing information on the incident acoustic pressure.
REFERENCES:
patent: 4446543 (1984-05-01), McLandrich et al.
patent: 5249163 (1993-09-01), Erikson
patent: 5311485 (1994-05-01), Kuzmenko et al.
patent: 5373487 (1994-12-01), Crawford et al.
patent: 5504719 (1996-04-01), Jacobs
Antonelli Lynn T.
Walsh Kenneth M.
Gauthier Robert W.
Lall Prithvi C.
Lobo Ian J.
McGowan Michael J.
The United States of America as represented by the Secretary of
LandOfFree
Photon transducer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photon transducer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photon transducer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2574149