OBJECTIVE LENS Russian patent published in 1998 - IPC

FIELD: telescope systems, such as night-vision telescopes. SUBSTANCE: objective lens has two components; first one has convex-convex lens and negative meniscus lens both glued together; second component has negative meniscus facing pattern with its concave side. The following relationships are satisfied here: , where is focal length of first component; is focal length of second lens of first component; f′ is focal length of objective lens; d₃ is air gap between first and second components; r₄, r₅ are curvature radii of second component spherical surfaces; n₃ is refractive index of second-component lens. The latter may be made of polymeric material. EFFECT: improved design. 2 cl, 3 dwg