| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: it is necessary to install a diaphragm mechanism using a liquid crystal cell in addition to a mechanical control type diaphragm mechanism in a conventional light quantity adjusting device, so that the number of components is increased and the mechanical constitution becomes complicated, and also, the constitution of a diaphragm drive circuit is complicated to upsize the whole device. SOLUTION: The light quantity adjusting device includes: a rotating member; a driving part for driving the rotating member; a plurality of aperture blades arranged while overlapping one another so as to form an aperture part, and engaging with the rotating member; and a cam member for operating the plurality of aperture blades so that the aperture part may have a prescribed aperture diameter with the rotation of the rotating member. In an engaging part between the rotating member and the driving member, the engaging surface of at least one of the members is formed to an inclined surface; and a clearance in a direction perpendicular to the optical axis in the engagement part between the rotating member and the driving part is changed based on the aperture diameter formed by the plurality of aperture blades. COPYRIGHT: (C)2009,JPO&INPIT
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