| 摘要 |
PURPOSE: To remove the uncomfortableness for a photographer by the nonconformity at the time of driving a plurality of ultrasonic actuators at the same time for drive of equipment, in short, beat phenomenon. CONSTITUTION: At least first and second ultrasonic actuators 10 and 12 being driven with specified frequency for drive of equipment are installed inside equipment such as a camera, or the like. These first and second ultrasonic actuators are driven and controlled with substantially the same frequency by the first and second ultrasonic drivers 11 and 13 controlled with an equipment controller 14. For example, when defined that the drive frequency of the first actuator and that of the second actuator are f1(Hz) and f2(Hz), respectively, they are constituted so that these may fulfill the relation of |f1-f2|<1000. |
