HIGH-APERTURE LENS FOR INFRARED SPECTRUM REGION Russian patent published in 2017 - IPC G02B13/14 G02B9/06 G02B11/02 

FIELD: physics.

SUBSTANCE: lens contains two single positive menisci facing the plane of objects with convexity. The second surface of the first meniscus is aspheric. Menisci are made from germanium. The ratios are performed: R₁=(1.04÷1.26)F; R₂=(1.03÷1.62)F; R₃=(0.5÷0.79)F; R₄=(0.59÷0.98)F, where R₁, R₂ - the radii of curvature, respectively of the first and the second surfaces of the first meniscus, R₃, R₄ - the radii of curvature, respectively, of the first and the second surfaces of the second meniscus, F - the lens focal length. To focus the lens at a finite distance and to compensate for the displacement of the image plane in the temperature range from minus 40°C to 50°C, the second meniscus or the entire lens is made movable along the optical axis.

EFFECT: increasing the view field of the lens while maintaining high image quality.

3 cl, 4 dwg, 2 tbl