DOUBLE-SPECTRUM INFRARED LENS HAVING APERTURE DIAPHRAGM IN IMAGE SPACE Russian patent published in 2011 - IPC G02B13/14 G02B9/64 

FIELD: physics, optics.

SUBSTANCE: lens can be used in thermal imaging devices based on cooled matrix receivers which are sensitive in ranges 3-5 mcm and 8-12 mcm. The first positive component consists of a negative meniscus whose concave surface faces the plane of the aperture diaphragm, a biconvex and a biconcave lens. The positive second component consists of five lenses. Between the first and second components there is a third component which is a positive meniscus whose concave surface faces the plane of the aperture diaphragm and lies at distance of not more than 0.15 times the focal distance of the first component in front of the plane of the intermediate image formed by the first and third components. Optical power of the components and optical properties of their materials satisfy relationships given in the claim.

EFFECT: shorter distance from the aperture diaphragm to the image plane, reduction of the diameter of the lenses of the first component to the diameter of the entrance pupil of the lens, reduced weight, exclusion of aspherical surfaces with high image quality in the middle and far infrared ranges with fixed position of the image plane.

6 dwg, 2 tbl