| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized focusing device by which a diaphragm plate can be moved freely forwards and backwards in a photographing luminous flux with a single driving motor and the position of a pupil aperture can be changed. SOLUTION: This focusing device is provided with a driving motor 48 rotatable in the normal and reverse directions, a sun gear 45 turned by the driving force of the driving motor 48, the diaphragm plate 41 which is meshed with the sun gear 45 by a peripheral gear part and where plural pupil aperture parts 41b and 41c and a sensing hole 41d are formed, a connecting plate 42 for connecting the rotary shaft 41a of the plate 41 to the rotary shaft 45 of the sun gear 45 and a position detector 43 arranged at the connecting plate 42 and detecting the sensing hole 41d, and an entering position and a retracting position to/from a photo-graphing luminous flux passing range P are moved because the plate 41 is revolved in accordance with the rotating direction of the driving motor 48, and the driving motor 48 is rotated in one rotation more when the it is at the entering position, so that the positions of the pupil apertures 41b and 41c are changed because of the self-rotation of the plate 41. |
