INFRARED LENS WITH TWO FIELDS OF VISION AND A DISTANT APERTURE DIAPHRAGM Russian patent published in 2020 - IPC G02B13/14 G02B15/14 

FIELD: physics.

SUBSTANCE: infrared lens consists of four components, the first of which is a single fixed positive meniscus whose convex surface faces the object space, second is a movable negative biconcave lens, the third is a fixed positive, including a positive meniscus whose convex surface faces the object plane, and a negative meniscus whose convex side faces the image space and a biconvex lens, and a fourth is a fixed positive component including a single positive convex-concave lens facing the object plane with its convexity, the second surface of which is asphero-diffracted. All surfaces of the lenses of the first, second and third components are spherical.

EFFECT: reduced number of aspherical surfaces while preserving the number of optical elements, as well as maintaining the magnification of the field of vision and high image quality.

1 cl, 8 dwg, 1 tbl