WIDE-ANGLE LENS Russian patent published in 2012 - IPC G02B9/62 

FIELD: physics.

SUBSTANCE: lens has a plane-convex lens whose plane side faces the object, a plane-concave lens whose plane side faces the object, a single biconvex lens, a biconcave lens glued with a biconvex lens, a single biconvex lens, a single divergent-meniscus lens whose concave side faces the image. The following relationships are satisfied in the lens: 1.63<n₁=n₂<1.68; 1.73<n₅<2.1; 1.57<n₆<1.64; 1.6<n₈<1.675, where: n₁ n₂ n₅, n₆, n₈ denote refraction indices of the material of the first and second lenses of the first component, the biconcave and biconvex lenses of the third component and the meniscus lens of the fourth component for line d, respectively. There is an aperture diaphragm in front of the biconcave lens. A plane-parallel plate or a light filter can be placed in front of the biconcave lens.

EFFECT: high aperture ratio and field angle in the object space with high image quality.

2 cl, 1 dwg, 2 tbl