| 摘要 |
PROBLEM TO BE SOLVED: To suppress inclination of the blade by a simple structure while opening/closing a front of a lens system by a rotationally operated barrier blade having a plurality of blades, and prevent occurence of a blade level step difference or an operation failure.SOLUTION: A rotary shaft 21 provided in a state of protruding from a barrier cover 11 has three-step level difference different in an outer diameter. A part of the largest outer diameter of the rotary shaft 21 is a rotary shaft part where each of two blades 14 and 15 arranged on an object side is operated. A part of an intermediate outer diameter having the second largest outer diameter of the rotary shaft 21 is a rotary shaft part where only a blade 13 serving as an overlapping barrier blade is rotated. A part of the smallest outer diameter smaller in a small diameter than the intermediate outer diameter is formed at a top end part of the rotary shaft 21. On a barrier board 12, a recess part is formed that can insert the part of the smallest outer diameter, and a plane part of a level difference step formed by a difference between the smallest outer diameter and the intermediate outer diameter on the rotary shaft 21 comes into contact with the barrier board 12 to thereby determine a distance between the barrier cover 11 and the barrier board 12. |
