| 摘要 |
PROBLEM TO BE SOLVED: To reduce an biasing force to bias a retreating lens frame toward a photographing optical axis, and also, to improve operational stability when moving the retreating lens frame along the optical axis direction. SOLUTION: A third-group sub-guide shaft 33 is magnetized, and the sub guide shaft contact part 31b of the third lens holding frame (retreating lens frame) 31 is formed to a columnar shape of a ferromagnetic body, and rotatably disposed in the third lens holding frame 31 while using a sub guide shaft contact part stopper 31c as a bearing. As a third-group female screw member releases a force against the rotating biasing force of a compression torsion spring applied to the third lens holding frame 31, the third lens holding frame 31 located at the retreat position finally comes into contact with the third-group sub-guide shaft 33, then, the third lens group in the third lens holding frame 31 is stably held on the optical axis. When the third lens holding frame 31 moves along the photographing optical axis in the state where the third lens group is on the optical axis, the sub guide shaft contact part 31b is rotated in contact with the third-group sub-guide shaft 33. COPYRIGHT: (C)2010,JPO&INPIT
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