Afocal optical device for use in front of e.g. night vision binocular body, has lens assembly forming image from another image at infinity, where former image is in same direction as luminous object, exit pupil and input pupil image

摘要

The device has a lens assembly (M1) e.g. Mangin mirror, operating by reflection and equivalent to a concave mirror, and another lens assembly (M2) operating by reflection and equivalent to another mirror. The assembly (M1) forms a real image from a luminous object to infinity at its focus, and the assembly (M2) forms an inversed real image from the former image. A third lens assembly (E3) i.e. eye-piece, forms a third image from the latter image at infinity, where the third image is in a same direction as that of luminous object, exit pupil of system and an input pupil image of a device.