| 摘要 |
PROBLEM TO BE SOLVED: To obtain a light quantity adjusting device maintaining optical performance and improving the degree of freedom in terms of optical design. SOLUTION: The light quantity adjusting device includes: a rotating member; a driving part for driving the rotating member; a plurality of diaphragm blades arranged to be superposed on each other so as to form an aperture part and engaged with the rotating member; and a cam member for actuating the plurality of diaphragm blades so that the aperture part may be set to a predetermined opening by the rotation of the rotating member. An abutting part is formed on the diaphragm blade, and also a slope part abutting on the abutting part is formed on the cam member or the rotating member, and the abutting part moves along the slope part with the actuation of the diaphragm blade. The slope part is formed so that the pushing-up of the aperture part of the diaphragm blade in the optical axis direction may be smaller by pressing the abutting part in an opposite direction to the optical system in an optical axis direction as the plurality of diaphragm blades are actuated from an open side to a small diaphragm side. COPYRIGHT: (C)2009,JPO&INPIT
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