Method for manufacturing low noise piezoelectric transducer
First Claim
1. A method for producing a piezoelectric element, comprising the steps of:
- providing a pair of electrodes,disposing between said electrodes a piezoelectric layer containing first and second inorganic piezoelectric materials having different coercive forces;
impressing a first direct current voltage between said pair of electrodes to polarize said first and second inorganic piezoelectric materials in one direction; and
then impressing a second, direct current voltage between said pair of electrodes to polarize the one of said first and second inorganic piezoelectric material whose coercive force is smaller than that of the other, in a direction opposite to said one direction so that one of the d31, d33 and dh properties of said element is made substantially zero.
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Abstract
A high unidirectivity piezoelectric element whose d31, d33 or dh is substantially zero. The element may be in the form of a sheet or a cable and includes a pair of electrodes, and a piezoelectric layer interposed between the pair of electrodes and containing two, first and second inorganic piezoelectric materials which have different coercive forces from each other and which are polarized in opposite directions. The element may be obtained by first applying a direct current voltage to a layer containing the first and second piezoelectric materials to polarize the both piezoelectric materials in one direction, and then applying a reverse direct current voltage thereto so that one of the piezoelectric materials having a smaller coercive force is selectively polarized in the other direction.
42 Citations
15 Claims
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1. A method for producing a piezoelectric element, comprising the steps of:
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providing a pair of electrodes, disposing between said electrodes a piezoelectric layer containing first and second inorganic piezoelectric materials having different coercive forces; impressing a first direct current voltage between said pair of electrodes to polarize said first and second inorganic piezoelectric materials in one direction; and then impressing a second, direct current voltage between said pair of electrodes to polarize the one of said first and second inorganic piezoelectric material whose coercive force is smaller than that of the other, in a direction opposite to said one direction so that one of the d31, d33 and dh properties of said element is made substantially zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification