TELEPHOTO LENS Russian patent published in 2017 - IPC G02B13/02 G02B9/10 

FIELD: physics.

SUBSTANCE: telephoto lens consists of two components, the first of which consists of two glued lenses - biconvex and biconcave, and the second component is a single negative meniscus, which concave side faces the object. In a telephoto lens, the proportions between the amount of the air gap between the first and second components, the focal distance of the lens, the radii of the first and second optical surfaces, the refractive indices and the dispersion coefficients for the D line of the material of the first, second and third lens are met in the formula of the invention.

EFFECT: decrease in the ratio of the lens length to the focal distance, increase in the ratio of the back focal distance to the focal distance and increase in the angular field in the space of objects.

2 cl, 1 dwg, 3 tbl