OPTICAL AXIS SHIFTING OPTICAL SYSTEM AND OPTICAL AXIS BRANCHING ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide an optical axis shifting optical system which can optionally set the ratio of reflected light and transmitted light by coating. SOLUTION: A second type Porr prism 28 is used together with an objective optical system. This second type Porr prism 28 has two pairs of reflecting surfaces 28a to 28d which invert the light transmitted through the objective optical system and emitted from a subject in two directions intersecting orthogonally with the optical axis Ax of the objective optical system and intersecting orthogonally with each other. These reflecting surfaces 28a to 28d respectively perpendicularly bend the optical axis of the objective optical system. The first reflecting surface 28a disposed right behind the objective optical system is subjected to partial reflection coating and the refractive index of the medium on the rear side thereof is greater than the refractive index of the medium on the front side.