| 摘要 |
PURPOSE:To open shutter blades at a constant speed without reference to the stop position of a lens driving ring by stopping the operation of a stepping motor temporarily after the focusing operation of a lens and then starting opening the shutter blades. CONSTITUTION:The rotation of the shaft wheel 3 of the stepping motor is transmitted to a gear surface 1a through gears 4 and 5. A blade driving ring 1 is so constituted as to open the shutter blades by clockwise rotation. A lens driving ring 6 is energized clockwise by a spring 26, but a step 6a abuts on a lock member 1b implanted in the blade driving ring 1 to restrict the rotation. Here, the operation of the stepping motor is stopped after the focusing operation of the lens, and then the opening operation of the shutter blades is started. Consequently, the influence of the force of the spring 26 energizing the lens driving ring 6 upon the stepping motor is cut off without reference to the position of the stopping operation, and the shutter blades are opened stably. |
