HIGH-APERTURE LENS Russian patent published in 2017 - IPC G02B9/60 

FIELD: photography.

SUBSTANCE: lens can be used as a photographic lens. High-aperture lens consists of two optical components, separated by an air gap. First component consists on beam path of three positive menisci and one negative meniscus, whose convex surfaces face object plane, third positive and fourth negative menisci glued together. Second component consists of a meniscus which is glued from a biconcave and biconvex lenses with radii equal in magnitude, whose convex surface faces image plane. Following ratios are met: 1.59<n₁=n₂<1.64, 1.72<n₄=n₇<1.77, 1.5<n₅<1.6, where n₁, n₂, n₄, n₅ and n₇ – refraction indices of material of first, second, fourth, fifth and seventh lenses, respectively, for spectral line D.

EFFECT: technical result is high aperture ratio, larger angular field in object space and improved manufacturability.

1 cl, 2 dwg, 2 tbl