PIEZOELECTRIC ELEMENT, STATOR FOR OSCILLATORY WAVE MOTOR, OSCILLATORY WAVE MOTOR, DRIVING CONTROL SYSTEM, OPTICAL APPARATUS, AND METHOD FOR MAKING STATOR FOR OSCILLATORY WAVE MOTOR

摘要

The present invention provides a piezoelectric element that includes a piezoelectric material having first and second surfaces; a common electrode disposed on the first surface; and a plurality of drive phase electrodes, a detection phase electrode, and a non-drive phase electrode disposed on the second surface, the piezoelectric material being sandwiched between the common electrode and the electrodes on the second surface. An absolute value d(1) of a piezoelectric constant of the piezoelectric material (1) in portions sandwiched between the drive phase electrodes and the common electrode, an absolute value d(2) of a piezoelectric constant of the piezoelectric material (2) in a portion sandwiched between the detection phase electrode and the common electrode, and an absolute value d(3) of the piezoelectric material (3) in a portion sandwiched between the non-drive phase electrode and the common electrode satisfy d(2)<0.95d(1), d(3)<0.95d(1), and 0.9≦̸d(3)/d(2)≦̸1.1.