Membrane hydrophone having inner and outer membranes
First Claim
1. An acoustic device comprising:
- a support structure having an interior;
an outer suspension membrane fixed to said support structure and extending from said support structure to said interior, said outer suspension membrane having an opening therethrough;
an inner transducer membrane suspended within said interior in spaced relation to the support structure by said outer suspension membrane, said inner transducer membrane having a piezoelectrically active area aligned with said opening through said outer suspension membrane;
means for attaching said outer suspension membrane to said inner transducer membrane; and
electrode means for conducting electrical charge from said piezoelectrically active area.
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Accused Products
Abstract
An acoustic device, such as a membrane hydrophone, includes a support structure and an outer membrane that suspends a transducer membrane within the interior of the support structure. The transducer membrane is selected for its acoustic and piezoelectric properties and is preferably a polymer such as P(VDF-TrFE). The outer suspension membrane is selected primarily for its mechanical properties. Portions of the suspension membrane may be removed in order to reduce mechanical drag encountered during movement of the device in a liquid. The transducer membrane includes at least one active area that is poled to provide a piezoelectrically strong region. Electrical charge generated at the active area is amplified at a preamp for transmission to remote equipment.
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Citations
20 Claims
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1. An acoustic device comprising:
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a support structure having an interior; an outer suspension membrane fixed to said support structure and extending from said support structure to said interior, said outer suspension membrane having an opening therethrough; an inner transducer membrane suspended within said interior in spaced relation to the support structure by said outer suspension membrane, said inner transducer membrane having a piezoelectrically active area aligned with said opening through said outer suspension membrane; means for attaching said outer suspension membrane to said inner transducer membrane; and electrode means for conducting electrical charge from said piezoelectrically active area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A hydrophone comprising:
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a support membrane; a planar first membrane having an inside edge and an outside edge, said first membrane coupled at said outside edge to said support member; a piezoelectric polymer membrane connected to said first membrane proximate to said inside edge, said piezoelectric polymer membrane having a poled active area having an acoustic propagation axis, said first membrane and said piezoelectric polymer membrane being generally parallel and being offset in the direction of said acoustic propagation axis; and means electrically connected to said poled active area for conducting electrical charge therefrom. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A hydrophone comprising:
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a support structure having an interior; an annular outer suspension membrane fixed to said support structure and extending from said support structure to said interior; an inner transducer membrane suspended within said interior in spaced relation to the support structure by said outer suspension membrane, said inner transducer membrane having a piezoelectrically active region, the area of said active region being smaller than the entire area of said inner membrane; and electrode means for conducting electrical charge from said piezoelectrically active region.
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Specification