INFRARED LENS WITH SMOOTHLY VARYING FOCAL DISTANCE Russian patent published in 2016 - IPC G02B13/14 G02B15/16 G02B9/64 

FIELD: optics.

SUBSTANCE: lens comprises five components. First component comprises a convex-concave meniscus made from silicon and a biconcave lens from fluorite. Second component is biconcave lens made of silicon. Third component comprises a convex-concave positive meniscus made from silicon and negative convex-concave meniscus made from fluorite. Fourth - a positive convex-concave meniscus from silicon. Fifth component includes doubly-concave lens from fluorite and doubly-convex lens from silicon. First surface of the lens of the second component, the first surface of the first lens of the third component and the second surface of the second lens of the fifth component are tapered. Second and fourth components and the second lens of the fifth component are movable. Fourth component at changing the focal distance of the lens in the whole range of its values moves at first in one direction with movement of the second component, and then in reverse. Relative optical power of the second and fourth components satisfy conditions given in the patent claim.

EFFECT: wider range of changing the focal distance lens with simultaneous reduction of relative length of the lens and longitudinal movements of movable elements, high spectral transmission and thermal stability of the lens.

1 cl, 6 dwg, 2 tbl