Ultrasonic motor and electronic apparatus equipped with ultrasonic motor

Abstract

An ultrasonic motor comprises a piezoelectric element having first and second surfaces. Electric patterns are disposed on the first surface of the piezoelectric element at nearly equal intervals in a multiple of four, with each pair of two neighboring electrode pattern corresponding to a region of the piezoelectric element which has an alternately reversed direction of polarization. First and second circuit devices short-circuit every other one of the electrode patterns to form two electrode pattern groups. A vibrating member is disposed on the second surface of and electrically connected to the piezoelectric element. Projections are disposed on the surface of the vibrating member near every other one of the boundaries of the electrode patterns. An oscillation driving circuit detects oscillation data from one of the electrode patterns short-circuited by the first circuit device, performs phase adjustment and amplification of the vibrating wave generated by the piezoelectric element, and inputs a driving signal to one of the electrode patterns short-circuited by the second circuit device. A moving member is movably disposed on the vibrating member, and a pressure-regulating member urges the moving member into pressure contact with the vibrating member.