DUAL BAND INFRARED LENS Russian patent published in 2013 - IPC G02B9/60 G02B13/14 

FIELD: physics.

SUBSTANCE: lens has four components. The first and fourth components are in form of positive menisci made of the same material, the concave surfaces of which face the image plane. The first component has relative optical power of 0.6-0.8. The second component is in form of a biconcave lens. The third component is in form of two positive menisci whose concave surfaces face the image plane. The second component and the second meniscus of the third component are made of materials different from the material of the first and fourth components and have in spectral ranges 3-5 mcm and 8-12 mcm, average dispersion coefficients which differ by more than fivefold, with quasi-equal partial dispersion coefficients. Components of the lens have the following relative optical power values in accordance arrangement thereof on the beam path: (0.6-0.8); -(0.5-0.6); (0.6-0.7);-(0.2-0.3); (0.9-1.0).

EFFECT: recording a thermal image in the 3-5 mcm and 8-12 mcm ranges with a fixed position of the image plane and smaller diameter of components.

2 cl, 6 dwg, 1 tbl