SIGHT WITH VARIABLE MAGNIFICATION Russian patent published in 2000 - IPC

FIELD: optics. SUBSTANCE: sight includes lens, inversion optical system made of two components, collective lens and eye-piece. Components of inversion optical system have same optical force, mobile field component is inserted behind image plane of lens. Focal distance of field component amounts to 1.0-1.3 of focal distance of component of inversion system. Field component can be manufactured in the form of negative and positive lenses glued together. Focal distances of field component, negative and positive lenses making this component and their dispersion coefficients are interrelated by given relations. Each component of inversion optical system can include negative and positive lenses. Focal distances of glued component of inversion system, negative and positive lenses making this component are interrelated by means of given relations. Eye-piece can be composed of three lenses, one negative and two positive, produced from same material whose dispersion coefficient ν_D corresponds to condition 50,0 ≤ ν_D≤ 70,0. EFFECT: not more than five brands of glass are used, resolution limit is improved with magnification ratio not less than three. 4 cl, 1 dwg, 1 tbl