OBJECTIVE LENS FOR CLOSER IR-SPECTRUM Russian patent published in 2017 - IPC G02B13/14 G02B9/34 

FIELD: physics.

SUBSTANCE: objective lens contains an aperture diaphragm and four components. The first component is a positive meniscus inverted with a bulge to the object, glued from a biconvex and biconcave lens. The second one is a positive meniscus, which is turned by convexity to the object and is glued from a biconvex and biconcave lens. The third one is a negative meniscus turned by a bulge to the image, glued together from the negative and positive menisci. The fourth one is a negative meniscus, which is turned by convexity to the image. The focal lengths of the components satisfy the conditions: F₀/F₁=0.1÷1.0; F₂/F₀=0.5÷0.9; F₀/|F₃|=0.1÷1.0; |F₄|/F₀=0.5÷0.9, where F₁, F₂, F₃, F₄, F₀ - focal lengths of the first, the second, the third, the fourth components and the lens, respectively.

EFFECT: increasing the image quality, reducing the length and increasing the working length of the lens.

7 cl, 6 dwg, 4 tbl