Driving method of piezoelectric actuator, piezoelectric actuator, and disk recording and reproducing apparatus using the same

Abstract

In a disclosed method, a piezoelectric elementhas an asymmetrical hysteresis characteristic of polarization-electric field different in absolute values between a coercive field of positive electric side and a coercive field of negative electric field side, and is polarized in the film thickness direction of the piezoelectric elementand in a direction of smaller absolute value of the coercive field, and as a position control voltage Qfor position control by ditorting the piezoelectric elementin a direction orthogonal to the film thickness direction of the piezoelectric elementa voltage equivalent to an electric field of 0.4 or less of the coercive field value is applied in the film thickness direction of the piezoelectric elementin a direction of larger absolute value of the coercive field. Further, a position control voltage Qfor recovering from deterioration of polarization of the piezoelectric elementis applied by superposing on the position control voltage Q, or changing over with the position control voltage Q, or while the position control voltage Qis not applied, and therefore recovering from deterioration of polarization characteristic, the displacement characteristic is stabilized for a long period of time.