Optical system for averted vision and averted vision

摘要

The present invention relates to an optical system (60, 70) for a side-viewing endoscope, the optical system having a lateral viewing angle θ. The optics comprises a distal optic assembly having a group of prisms. The prism group is configured to convert incident light from a field of view defined around a lateral viewing angle in the direction of the longitudinal axis of the endoscope with a first reflecting surface (65, 77) and a second reflecting surface (66, 78). And two or more prisms (62, 63, 72, 73, 74), whose adjacent border surfaces are paired parallel to each other. It is arranged and comprises two or more prisms, each separated by a gap (64, 75, 76). Total internal reflection of some of the incident light from outside the field of view occurs at the interface between the prism and the subsequent gap. The prism group has a cylindrical tube (85) having a diameter D. The first prism on the entrance side of the prism group is designed in a wedge shape having a wedge angle β and a length a of the optical path of the central beam path. The entrance surface of the first prism has a length L defined as the intersection line between the entrance surface and the plane covered by the central beam path. Further, the present invention relates to a side-viewing endoscope. According to the present invention, the first prism satisfies the following conditions: a