Patent ID: 8186812

Claim:
A piezoelectric actuator comprising: a first piezoelectric layer; a second piezoelectric layer which is stacked on the first piezoelectric layer; a first electrode which is arranged on the first piezoelectric layer, on a side opposite to the second piezoelectric layer; a second electrode which is arranged between the first piezoelectric layer and the second piezoelectric layer; and a third electrode which is arranged on the second piezoelectric layer, on a side opposite to the first piezoelectric layer, wherein a portion of the third electrode faces the second electrode and another portion, of the third electrode, not facing the second electrode faces the first electrode, the first electrode is arranged not to face at least a portion of the second electrode, a portion of the second piezoelectric layer, sandwiched between the second electrode and the third electrode is polarized in a first direction in a thickness direction of the second piezoelectric layer, and a portion of the first piezoelectric layer and a portion of the second piezoelectric layer, which are sandwiched between the first electrode and the third electrode and between which the second electrode is not arranged, are polarized in a direction opposite to the first direction, and an area of the first piezoelectric layer and the second piezoelectric layer, sandwiched between the first electrode and the third electrode and between which the second electrode is not arranged, is larger than an area of the first piezoelectric layer, sandwiched between the first electrode and the second electrode.