WIDE-ANGLE LENS Russian patent published in 2017 - IPC G02B9/64 

FIELD: physics.

SUBSTANCE: lens has four components. The first component consists of a negative meniscus, which convex side faces the object, and a biconcave lens. The second component is a single negative meniscus, which convex side faces the object, and which is able to move along the optical axis. The third is a biconvex lens. The fourth component contains two positive meniscus, which convex side faces the object, between which a single negative meniscus is located, which concave side faces the image. Between the third and the fourth components there is a plane-parallel plate or light filter. The following ratio is fulfilled: Δl₂≤0.1⋅ƒ'_lens, where Δl₂ is amount of movement of the second component along the optical axis; ƒ'_lens is focal distance of the lens.

EFFECT: increasing relative aperture and field of view while maintaining image quality in a narrow spectral range and in an extended temperature range.

1 dwg, 1 tbl