| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress a noise in a slight motion mode in a drive device. <P>SOLUTION: A vibration actuator has a piezoelectric element, a driver provided on the piezoelectric element, and a movable body supported by the driver. A controller supplies first and second voltages having the same frequency to the piezoelectric element. The controller supplies the first voltage and the second voltage having a phase different by 90° from the first voltage to the piezoelectric element, thereby vibrating the piezoelectric element so that expansion/shrinkage vibration is combined with torsional vibration of a secondary mode, and the vibration moves the driver in a substantial elliptic circular manner to move the movable body. In the slight motion mode, the phase difference of the first and second voltages is switched between 90° and a prescribed angle which is larger than 0° and less than 90° by the controller. <P>COPYRIGHT: (C)2012,JPO&INPIT |
