Patent ID: 8477417
Filing Date: 2013-07-02
Classification: G02B

Abstract:
1. An imaging optical system that forms an image through an objective lens and an observation optical system and that is configured to be able to change the magnification of the image, wherein the observation optical system comprises a plurality of optical paths and ejects light from the objective lens from each of the plurality of optical paths, and each of the optical paths comprises a plurality of lens groups, in at least one of the plurality of optical paths, each of at least two lens groups among the plurality of lens groups moves in a direction including a component perpendicular to a reference optical axis of the observation optical system at at least part of a section where the magnification is changed from a high-power end state to a low-power end state, at least one of the lens groups that move in the direction including the component perpendicular to the reference optical axis of the observation optical system is a first correction lens group that moves so that a position of light passing outermost from an optical axis of the objective lens moves toward the optical axis of the objective lens compared with a case of moving in a direction including only a component substantially parallel to the reference optical axis, when the magnification is changed from the high-power end state to the low-power end state, and remaining lens groups of the lens groups that move in the direction including the component perpendicular to the reference optical axis of the observation optical system is a second correction lens group that corrects the optical paths changed by the first correction lens group.