OPTICAL SYSTEM Russian patent published in 2014 - IPC G02B23/00 F41G1/38 

FIELD: physics.

SUBSTANCE: optical system comprises a lens, a glaring element with a reflecting surface situated in the vicinity of the focal surface of the lens, and an aperture mask, having a region which transmits optical radiation without distortion of the wave front and made in form of a segment larger than a half-circle and a region which does not transmit radiation. The boundary of said region in form of a chord which closes the segment lies at a distance d from the centre of the lens aperture, selected such that d=αF, where F is the focal length of the system lens, m; α is the maximum angle of inclination of a parallel light beam incident on the lens aperture to a plane passing through the optical axis of the system parallel to the chord, rad; wherein all rays of said beam reflected from the glaring element independent of the inclination side thereof fall on the region of the mask which does not transmit radiation.

EFFECT: wider field of vision in which a radiation source can be located without causing considerable light reflection towards the side of the plane passing through the optical axis of the system parallel to the edge of the region of the aperture mask which does not transmit optical radiation, where the region of the mask which does not transmit radiation is situated.

5 cl, 4 dwg