Piezoelectric transducer
First Claim
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1. A piezoelectric transducer comprising:
- a single material piezoelectric base molded as a curved plate, wherein an entire4ty of said piezoelectric base is formed of a material having an electromechanical coupling factor Kp ≦
0.3 for vibration diffusing in a planar direction;
a first electrode formed on one surface of said piezoelectric base and in contact with said material having an electromechanical coupling factor Kp ≦
0.3, and second electrodes formed on an other surface of said piezoelectric base in contact with said material having an electromechanical coupling factor Kp 0.3, said second electrodes being divided concentrically in such a way that divided sections are insulated from one another, wherein no otehr materials than said material with said electromechanical coupling factor Kp ≦
0.3 are between said first and second electrodes.
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Abstract
A piezoelectric transducer having electrodes formed on both surfaces has a piezoelectric base molded as a curved plate which can converge sound fields of acoustic waves at an arbitrary point and which can reduce noise or reverberation in a lateral direction which otherwise occur due to unnecessary vibration. At least one of the electrodes is divided concentrically. A material having a small electromechanical coupling factor Kp in the lateral direction is used for the piezoelectric material, preferably porous PZT.
109 Citations
20 Claims
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1. A piezoelectric transducer comprising:
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a single material piezoelectric base molded as a curved plate, wherein an entire4ty of said piezoelectric base is formed of a material having an electromechanical coupling factor Kp ≦
0.3 for vibration diffusing in a planar direction;a first electrode formed on one surface of said piezoelectric base and in contact with said material having an electromechanical coupling factor Kp ≦
0.3, and second electrodes formed on an other surface of said piezoelectric base in contact with said material having an electromechanical coupling factor Kp 0.3, said second electrodes being divided concentrically in such a way that divided sections are insulated from one another, wherein no otehr materials than said material with said electromechanical coupling factor Kp ≦
0.3 are between said first and second electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 17, 18)
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13. A piezoelectric transducer comprising:
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a single material piezoelectric base formed entirely of a porous material of a porosity of at least 30 vol%; at least one first electrode formed on one surface of the base and in contact with said porous material; a plurality of second electrodes formed on an other surface of said base and in contact with said porous material; wherein said second electrodes are formed to be separated sections which are arranged concentrically and electrically and mechanically insulated from each other and wherein only said porous material, and no other materials, are between said first and second electrodes. - View Dependent Claims (14, 15, 16, 19, 20)
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Specification