FOCUS POSITION CHANGING DEVICE AND CONFOCAL OPTICAL DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a focus position changing device capable of suppressing reflected light from a rotary body and a confocal optical device using the same.SOLUTION: A focus position changing device is provided on an optical path of a confocal optical device including a light source and an objective lens, to change a focus position of an objective lens in an optical axis direction and includes: a plurality of optical path changing pieces 31 which are respectively made of parallel tabular transparent materials and are different from one another in at least one of refractive index and thickness; a rotary plate 32 which has the plurality of optical path changing pieces 31 arranged thereon along a rotation direction thereof so that they cross the optical axis of the objective lens, and has an anti-reflection layer 51 in a prescribed region of a surface 36 on the light source side; and a driving unit which rotationally drives the rotary plate 32.