Composite transducer
First Claim
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1. A composite transducer for operation in the less than 100 kilocycle range comprising:
- a longitudinal vibrator-type transmitter transducer having a transmitting head mass and face;
a rear mass;
a stack of piezoelectric ceramic elements between said head and rear masses for electrically producing vibration of said head face;
a piezoelectric polymer layer receiver hydrophone which is acoustically transparent at the frequency of operation of said transducer attached to and covering a substantial portion of said head face;
means for detecting the electrical potential produced in said polymer hydrophone; and
means terminating said pizeoelectric ceramic elements in an electrical impedance that improves said receiver hydrophone response and reduces said transmitter transducer self-noise.
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Abstract
The composite transducer of this invention comprises a prior art longitudinal vibrator-type transducer for transmission of energy and a piezoelectric polymer hydrophone attached to the radiating face of the transducer for the receiving function. During transmission the receiver transducer is short-circuited, and during reception the transmitter transducer is terminated in an electrical impedance that optimizes receiver response and minimizes transducer self-noise. The frequency response of the polymer hydrophone is relatively flat and extends over a much greater frequency range than the transducer.
20 Citations
9 Claims
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1. A composite transducer for operation in the less than 100 kilocycle range comprising:
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a longitudinal vibrator-type transmitter transducer having a transmitting head mass and face; a rear mass; a stack of piezoelectric ceramic elements between said head and rear masses for electrically producing vibration of said head face; a piezoelectric polymer layer receiver hydrophone which is acoustically transparent at the frequency of operation of said transducer attached to and covering a substantial portion of said head face; means for detecting the electrical potential produced in said polymer hydrophone; and means terminating said pizeoelectric ceramic elements in an electrical impedance that improves said receiver hydrophone response and reduces said transmitter transducer self-noise. - View Dependent Claims (2, 3)
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4. A composite transducer for operation in the less than 100 kilocycle range comprising:
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a longitudinal vibrator-type transmitter transducer having a head mass, said head mass having an exterior face; a rear mass; a stack of piezoelectric ceramic elements between said head and rear masses for electrically producing vibration of said head mass; a piezoelectric polymer layer having two sides, both of which are metallized, one of said sides being bonded to said face; said polymer layer being acoustically transparent at a frequency of operation of said transducer; means for making electrical connection to said metallized sides of said layer; means for covering said polymer layer and said transducer to electrically insulate and waterproof said layer and said transducer; and means terminating said piezoelectric ceramic elements in an electrical impedance that improves said polymer layer response and reduces said transmitter transducer self-noise. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification