INFRARED OBJECTIVE LENS WITH SMOOTHLY ALTERING FIELD OF VISION Russian patent published in 2012 - IPC G02B13/14 G02B15/16 G02B9/62 

FIELD: optics.

SUBSTANCE: objective lens can be applied for thermal imagery devices with smoothly altering field of vision; the objective lens contains the first consistently located fixed element in the form of a collecting convex-concave lens, the second movable element consisting of the first defocusing convex-concave lens and the second concavo-concave lens, the third movable component in the form of the convexo-convex lens and the last immovable component containing the first collective convex-concave lens and the second defocusing concave-convex lens; the focal distance f₁ of the first component is selected in accordance with the dependency: f₁=(from 0,545 to 0,8)f_t, wherein f₁ is the focal distance of the first component, f_t - the maximum focal distance of the objective lens.

EFFECT: demagnification of the length of the infrared objective lens regarding maximum focal distance upon the retention of sufficiently high image quality.

1 dwg, 3 tbl.