TWO-LENS OBJECTIVE Russian patent published in 2008 - IPC G02B9/10 

FIELD: optical instrument engineering.

SUBSTANCE: two-lens objective can be used in different optical systems as in visual and in IR-systems. Objective has first lens made in form of biconvex one, and second lens made in form of negative meniscus turned with its convexity to image. Lenses are made of optical glass being transparent in visible and near IR spectrum range. Radiuses of biconvex lens are equal in absolute value. Relation of first radius being disposed on path of beams of menisci lens to its second radius is shorter than 0,8. Relations are met as 1,46<n₁<1,63; 1,66<n₂<1,78 where n₁ and n₂ rare refractivity factors of material of first and second lenses along beam paths. Lenses can be single ones or glued ones.

EFFECT: simplified design; improved manufacturability; increased focal length; higher quality of image.