Patent ID: 7439659

Claim:
A piezoelectric actuator, comprising: a plate-shaped piezoelectric body which has a first portion polarized in a thickness direction of the piezoelectric body and a second portion polarized in a direction oblique to the thickness direction; and a pair of electrodes for polarizing the piezoelectric body and inducing strain in the piezoelectric body, the electrodes disposed on opposite surfaces of the piezoelectric body facing each other in the thickness direction across the piezoelectric body, wherein symmetry portions of one electrode of the pair of electrodes are plane-symmetrical with respect to symmetry portions of the other electrode of the pair of electrodes, and asymmetry portions of the one electrode are plane-asymmetrical with respect to corresponding asymmetry portions of the other electrode in relation to a plane of symmetry that bisects a plane of the piezoelectric body, the pair of electrodes polarizes the first portion of the piezoelectric body in the thickness direction and polarizes the second portion of the piezoelectric body in the direction oblique to the thickness direction, and the pair of electrodes induces strain in the first and second portions of the piezoelectric body.