| 摘要 |
PROBLEM TO BE SOLVED: To prevent the upsizing on one side in an optical axis direction which occurs when a magnet and yoke are arranged on one side in the optical axis direction bordering a plate and further a coupling yoke is arranged above the magnet and the consequent hindrance for the downsizing of the optical apparatus. SOLUTION: This light quantity adjusting device is constituted by disposing the magnet 104 on one side in the optical axis direction of the device plate 101 and a plurality of yokes 106, 107, 109 and 110 facing the magnet and adjusts the light quantity by driving the magnet by energization to coils 108 and 111 wound around these yokes and opening and closing light shielding vanes 102 and 103 connected to the magnet. A planar member (a retaining plate) 112 formed by a magnetic material is arranged on the other side in the optical axis direction of the device plate along the device plate and the plate member and the plurality of yokes are brought into contact with each other to form a closed magnetic circuit by these yokes, the magnet and the planar member.
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