| 摘要 |
PROBLEM TO BE SOLVED: To reduce driving resistance with a simple constitution and to shift a lens while keeping perpendicularity to an optical axis without backlash by supporting a movable member for holding the lens through a ball rotatable with respect to a reference plane surface perpendicular to the optical axis thereby preventing the turning around the optical axis of the movable member with an elastic member and pressing the movable member in an optical axial direction. SOLUTION: A movable frame 4 is supported in parallel with the reference plane surface 1b provided in a supporting frame 1 and being perpendicular to the optical axis, with three balls (steel balls) 2, without backlash in the optical axial direction, to attain shifting in a plane perpendicular to the optical axis 13. Therefore, optical performance is never degraded because of falling, the backlash, etc. The rolling friction of the balls 2 whose resistance is low is used to reduce shift driving force by electromagnetic drive. Further, the turning around the optical axis of the movable frame 4 is prevented by a pair of tension springs 6 facing each other and the pressing force of the movable frame 4 on the balls 2 is generated to prevent the backlash in the optical axial direction at the shifting time. |
