Drive circuit for surface-wave driven motor utilizing ultrasonic vibration

摘要

A surface-wave driven motor comprises a moving member for being displaced, a resilient member having a surface urged against the moving member, a piezo-electric member provided in contact with the resilient member to impart vibration to the resilient member and create an elastic wave in the surface, means having electrode means provided on the piezo-electric member and applying an AC voltage to the piezo-electric member through the electrode means, means for detecting an electrical output produced in the piezo-electric member from an area on the piezo-electric member which is electrically insulated from the electrode means, and means for determining the frequency of the AC voltage on the basis of the detected electrical output.