Wide-view telescopic optical system

Abstract

A lightweight and small-sized high-power monocular, or binoculars, including a wide-view telescopic optical system to have a wide view and a bright field of view is provided. The wide-view telescopic optical system includes a reverse reflection optical system interposed between an objective lens system and an eye lens system. The reverse reflection optical system includes a first reflector arranged at an angle of 45 degrees to an incident optical axis. The reverse reflection optical system also includes a right-angled isosceles triangle prism having roof surfaces whose ridge line is laid on an axis parallel with the incident optical axis so as to receive a reflected light from the first reflector at a part of an oblique side surface of the prism. The reverse reflection optical system further includes a second reflector arranged to oppose another part of the oblique side surface of the right-angled isosceles triangle prism from which light reflected by the prism is emitted. The second reflector is placed at an angle of 45 degrees with respect to the optical axis of reflected light emitted from the prism. The wide-view telescopic optical system also includes a relay lens located between the objective lens system and the eye lens system at a position adjacent the second reflector.