| 摘要 |
PURPOSE:To prevent the vibration and the step-out of a stepping motor by changing the driving frequency of the stepping motor in accordance with transformation magnification and driving the motor. CONSTITUTION:A driving device 50 drives a pulse motor PM to move a lens unit 3 and a 3rd mirror 4 in parallel with an optical axis and position them at positions which are optically decided, the the magnification of an optical system is transformed. The driving device 50 drives the pulse motor PM, especially, by changing the driving frequency of the motor PM in accordance with the transformation magnification. Thus, the vibration and the step-out of the stepping motor are prevented even when the stepping motor is driven to move the lens unit 3 and any mirror 4 simultaneously in order to transform the magnification. |
