OCULAR Russian patent published in 1997 - IPC

FIELD: optical instruments. SUBSTANCE: device has two members one of which is designed as negative meniscus which is glued from negative and positive lenses. Second meniscus is designed as single positive convexo-convex lens. Positive lenses of first and second members have identical curvature radius. Thickness ratio of negative and positive lenses in glued member is 1.5 : 1.0. Positive lenses are made from glass which refraction index is not greater than 1.62 and average dispersion index is 60.3. Negative lens is made from glass which refraction index is 1.75 and average dispersion index is 28. EFFECT: increased functional capabilities. 4 cl, 1 tbl, 2 dwg