| 摘要 |
PROBLEM TO BE SOLVED: To surely and stably open/close an optical path in a collapsible lens which has a small retreat space so as to be miniaturized and has a long aperture diameter so as to achieve a high magnification and a wide angle.SOLUTION: Barrier blades 123 and 124 supported on a barrier base 130 and a barrier opening/closing ring 140 supported on the barrier base 130 so as to be rotatable around an optical axis are connected, and a torsion spring 151 having one end fixed to the barrier blades 123 and 124 has the other end 151b pressed to the barrier opening/closing ring 140. The barrier opening/closing ring 140 includes: a positioning part 140a which is brought into contact with the other end 151b of the torsion spring 151 to hold a barrier blade 120 in an opening position; and a sliding part 140b which is brought into contact with the other end 151b of the torsion spring 151 and slides to hold the barrier blade 120 in a closing position. |
