| 摘要 |
PURPOSE:To eliminate the need to increase the gear ratio of a power transmission system and to eliminate the influence of variation, as well in power source voltage by providing a motor which drives a photographic optical system in the direction of the optical axis, a motor driving circuit, etc. CONSTITUTION:When the motor driving circuit 103 supplies a DC driving signal to the motor 102, the photographic optical system 101 is driven at high speed toward a specific position. Further, when a pulse driving signal is supplied to the motor 102 in the vicinity of the specific position, the optical system 101 is driven or stopped repeatedly in response to each pulse and thus driven intermittently toward the specific position. Further, when the optical system 101 reaches the specific position, the supply of the pulse driving signal is interrupted and the optical system 101 stops at the specific position. At this time, the optical system 101 stops at every interval of a puls, so the gear ratio of the power transmission system need not be increased and an overrun quantity is reduced while maintaining the moving speed of the optical system 101 based upon the DC driving signal in high speed. |
