BINOCULAR MICROSCOPE OBJECTIVE WITH SLIT LAMP Russian patent published in 2016 - IPC G02B9/12 G02B21/02 G02B13/18 

FIELD: physics.

SUBSTANCE: objective has series-arranged along optical axis first and second aspherical negative menisci and aspherical biconvex lens. First meniscus has first aspherical concave surface, facing object plane, and second convex spherical surface. Second meniscus has first aspherical convex surface, facing object plane, and second aspherical concave surface. And biconvex lens has first aspherical and second spherical surfaces. All lenses are made of different types of glass. Dispersion coefficient ν_(C) of first and second lenses is 25<ν_C<35, which is 2÷2.5 times less than dispersion coefficient of material of third lens. Ratios are met: f'₁=-(1.3÷1.5)f', f'₂=-(29.6÷30.0)f', f'₃=(0.5÷0.55)f', where f', f'_1, f'₂, f'₃ are focal distance of objective, first, second and third lenses. Light diameter D_L1 of first objective lens and total length of objective L_tot are in ratio 0.85<L_tot/D_L1<0.9.

EFFECT: increased level of aberration correction under condition of invariance of main objective parameters.

1 cl, 1 tbl, 1 dwg