DUAL-SPECTRUM LENS WITH DISCRETELY VARIABLE FOCAL DISTANCE Russian patent published in 2013 - IPC G02B15/02 G02B9/62 G02B13/14 

FIELD: physics.

SUBSTANCE: lens consists of a fixed component having a first positive convex-concave lens, a second convex-concave lens and a third negative convex-concave lens, and a movable component having a first lens, a second convex-concave lens and an additional third positive convex-concave lens. The focal distance is changed by moving the fixed component between the second and third lenses of the fixed component into and out of the optical channel. In the fixed component, the second lens is positive and in the movable component, the first lens is convex-concave and negative, and the second lens is positive.

EFFECT: high energy capacity of the lens.

7 cl, 1 dwg