| 摘要 |
PROBLEM TO BE SOLVED: To provide a light quantity adjusting device which secures the balance of a disk having an aperture when turning and also achieves the improvement of responsiveness when starting up the disk and the reduction of manufacture cost by making the disk light in weight and decreasing moment of inertia. SOLUTION: The light quantity adjusting device is equipped with: substrates 10 and 20 having aperture parts for exposure 11 and 21; the disk 30 supported to freely turn on the substrates 10 and 20 and equipped with an aperture 32 for opening/closing the aperture parts 11 and 21; and a driving source for turning the disk 30. The disk 30 is provided with a chipped part 34 on an opposite side to the aperture 32 while putting the turning center of the disk 30 in between and the center of gravity is aligned with the turning center of the disk 30, whereby the disk 30 is balanced. Thus, the balance of the disk 30 when turning is secured, and also the disk 30 is made light in weight, responsiveness when starting up the disk during the opening/closing actuation of the aperture parts 11 and 21 is improved and the manufacture cost of the disk is reduced. COPYRIGHT: (C)2007,JPO&INPIT
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