| 摘要 |
PURPOSE:To prevent unnecessary power consumption of a stepping motor for aperture control by releasing the stepping motor from being powered on detecting an open aperture state, and also locking the stepping motor mechanically. CONSTITUTION:An aperture ring 9 is rotated through a stepping motor SM for aperture control and when a diaphragm is opened, that is detected by the notch 6A of a disk 6 rotated by the motor SM and the projection 4A of a lever 4. Then, the projection 4A is fitted in the notch 6A to turn on a switch 9 through a lever 3, and while the motor SM is released from being powered off, the motor SM is locked mechanically by the notch 6A and projection 4A without reference to external oscillation, etc. Consequently, unnecessary power consumption of the stepping motor for aperture control is prevented. Further, the motor is unlocked through a magnet 2, etc. |
