| 摘要 |
PURPOSE: To improve the control property in repeat start by changing a traveling wave oscillation generated on the surface of an oscillator over to a stationary wave oscillation when the quantity of residual drive of an oscillatory wave motor has become smaller than a specified value, and retaining its stationary wave oscillation in case the next drive is anticipated subsequent to a stop of drive. CONSTITUTION: In an embodiment applied to a single-lens reflex camera, a controller is equipped with a microcomputer 1 on the side of a lens, photointerpreters 2 and 3, which measure the amount of shifting of a focus lens and the amount of shifting of a variable-power lens, and oscillatory wave motor drive circuits 4 and 5. And, this controls the drive of an oscillatory wave motor for focus consisting of a stator 35 and a rotor 36 and the drive of an oscillatory wave motor for variable power consisting of a stator 24 and a rotor 25. Here, the start response property in case of starting the oscillatory wave motor continuously is improved by controlling each oscillatory wave motor so that it may maintain stationary wave mode during the specified time after stoppage of drive by the soft processing of the microcomputer 1. |
