Laminated piezoelectric element

A laminated piezoelectric element comprising:

• a laminated piezoelectric element comprising piezoelectric layers composed of a ceramic capable of expanding and contracting upon application of a voltage, and internal electrode layers that supply voltage to the piezoelectric layers, the internal electrode layers and piezoelectric layers being alternately provided;
• a first external electrode layer provided on a side of the laminated piezoelectric element and electrically connected with the internal electrode layers;
• a second external electrode layer provided on a side of the laminated piezoelectric element and electrically connected with the internal electrode layers via the first external electrode layer;
• and,
• a third external electrode layer provided on a side of the laminated piezoelectric element and provided between the first external electrode layer and the second external electrode layer;
• wherein,
• when the maximum width of the laminated piezoelectric element in the direction perpendicular to the direction of lamination is taken to be W0, the width of the first external electrode layer is taken to be W1, the width of the second external electrode layer is taken to be W2, the width of the third external electrode layer is taken to be W3, the thickness (after curing) of the second electrode layer is taken to be T2, and the thickness (after curing) of the third external electrode layer is taken to be T3, a relationship exists in which W1>W3>W2, 2.5≦(W2/W0)×100≦60, and 0.05≦(T2/T3)≦300;
• and,
• the laminated piezoelectric element has a piezoelectric active section that expands and contracts when a voltage is applied, and the second external electrode layer is provided continuously in the direction of lamination of the piezoelectric layers in the piezoelectric active section.

A laminated piezoelectric element comprising:

• a laminated piezoelectric element comprising piezoelectric layers composed of a ceramic capable of expanding and contracting upon application of a voltage, and internal electrode layers that supply voltage to the piezoelectric layers, the internal electrode layers and piezoelectric layers being alternately provided;
• and,
• a first external electrode layer provided on a side of the laminated piezoelectric element and electrically connected with the internal electrode layers;
• wherein,
• when the maximum width of the laminated piezoelectric element in the direction perpendicular to the direction of lamination is taken to be W0, and the width of the first external electrode layer is taken to be W1, the relationship exists in which 2.5≦(W2/W0)×100≦60;
• and,
• the laminated piezoelectric element has a piezoelectric active section that expands and contracts when a voltage is applied, and the first external electrode layer is provided continuously in the direction of lamination of the piezoelectric layers in the piezoelectric active section.