| 摘要 |
PROBLEM TO BE SOLVED: To stably drive an ultrasonic motor at a low speed by providing a differentiation circuit that generates a sine-wave voltage which is applied across another electrode on a piezoelectric body by differentiating another sine-wave voltage and has a temporal phase difference of a specific angle. SOLUTION: A frequency dividing circuit 12 divides the frequency of a signal oscillated from an oscillation circuit 11 and a low-pass filter 13 generates a sine wave. A differentiation circuit 14 generates another sine-wave voltage which is applied across another electrode on a piezoelectric body and has a temporal phase difference of 90 deg.. An amplifier circuit 15 amplifies the power of the signals of different phases and drives an ultrasonic motor 14 by applying a driving voltage across a driving electrode on the piezoelectric body which is the driving source of the motor 16. Therefore, the motor 16 can be stably driven at a low speed and the noise of the motor 16 and adverse influences on the contacting surface which are generated when the motor 16 is driven at a low speed can be reduced. |
