| 摘要 |
PURPOSE:To enlarge variations in the optical axis direction and minute tiltings of a focus lens and improve detecting precision by composing a lens position detector of a focus lens driving motor, a rack member, a focus lens frame, a first guide ball, and a second guide ball, and providing a transmitting type light detecting member on a light shielding member which is an extension of the focus lens frame. CONSTITUTION:When a detector is connected to a power source, a focus motor 28 is driven and the driving force is transmitted to a fourth group movable frame 27 through a lead screw 28a and a rack 31 of the focus motor 28, while the fourth group movable frame 27 motions itself toward an original position by the guidance of a guide ball and sets its original position by means of a focus encoder 29. When the fourth group movable frame 27 is driven by virtue of the focus motor 28, variations of the optical direction of the fourth group movable frame 27 and minute tiltings of the fourth group movable frame 27 caused by the clearance between a first guide ball 30b and the fourth group frame 27 are enlarged by a long light shielding member whereby improves the detecting precision at a light detecting portion. |
