CATOPTRIC, ZERO-POWER, WIDE-FIELD-OF-VIEW OPTICAL SYSTEM WITH A POSTERIOR APERTURE STOP AND A LONG BACK FOCAL LENGTH

摘要

A catoptric, wide-angle optical system includes at least three mirrors. Only the last mirror on the beam path (22) has a positive optical power and all other mirrors have negative optical power. The sum of the optical powers of the mirrors is zero. An external posterior aperture stop (35) is located on the beam path (22) between the last mirror and the image plane (24). The back focal length of the optical system (20) is equal to or greater than an effective focal length of the optical system (20). The field of view is large, and typically at least 30-40 degrees in one plane.