DIOPTER ADJUSTMENT MECHANISM AND OPTICAL INSTRUMENT INCLUDING DIOPTER ADJUSTMENT MECHANISM

摘要

A diopter adjustment mechanism (20) comprising a shaft body (29) that is integrally rotated in response to an operation of the diopter adjustment dial (5), a driving unit (17-18) that moves a lens in an optical axis direction by rotation of the shaft body, bearing portions (31-32) that rotatably hold the shaft body in the vicinity of both ends of the shaft body, and a dustproof portion (30) that is arranged between the bearing portions of the shaft body, and blocks a first space continuous with an arrangement space of the diopter adjustment dial from a second space continuous with an arrangement space of the lens in a space around the shaft body, wherein the dustproof portion is circumferentially rotatable with respect to an outer peripheral surface of the shaft body, and is slidable in an axial direction of the shaft body.