| 摘要 |
A laminated piezoelectric element ( 1 ) comprises a laminated piezoelectric element ( 1 ) piezoelectric layers ( 11 ) composed of a ceramic capable of expanding and contracting upon application of a voltage, and internal electrode layers ( 21 a and 21 b) that supply voltage to the piezoelectric layers, the internal electrode layers and piezoelectric layers being alternately provided, a first external electrode layer ( 31 ) provided on a side of the laminated piezoelectric element ( 1 ) and electrically connected with the internal electrode layers ( 21 a and 21 b), and a second external electrode layer ( 32 ) provided on a side of the laminated piezoelectric element ( 1 ) and electrically connected with the internal electrode layers ( 21 a and 21 b) via the first external electrode layer ( 31 ); wherein, when the maximum width of the laminated piezoelectric element ( 1 ) in the direction perpendicular to the direction of lamination is taken to be W 0, the width of the first external electrode layer ( 31 ) is taken to be W 1, and the width of the second external electrode layer ( 32 ) is taken to be W 2, a relationship exists in which W 1 >W 2 and 2.5<=(W 2/ W 0 )x100<=60, and the laminated piezoelectric element ( 1 ) has a piezoelectric active section ( 1 a) that expands and contracts when a voltage is applied, and the second external electrode layer ( 32 ) is provided continuously in the direction of lamination of the piezoelectric layers ( 11 ) in the piezoelectric active section ( 1 a).
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