Patent attributes
An optical element position control mechanism includes an optical element holding member, a lead screw rotatable on a rotational axis parallel to movement direction of the optical element holding member, a linearly moving nut screw-engaged with the lead screw and engaged with the optical element holding member, and a rotation prevention device preventing the linearly moving nut from rotating about the lead screw. Rotations of the lead screw cause the linearly moving nut to move along the lead screw, a position of the optical element holding member being determined by the linearly moving nut. A biasing device is positioned between the linearly moving nut and the optical element holding member and is resiliently deformable in a plane substantially parallel to a plane which includes the rotational axis of the lead screw, and applies a biasing force against the linearly moving nut so as to be prevented from rotating.
