OBJECTIVE LENS Russian patent published in 2012 - IPC G02B9/34 

FIELD: physics.

SUBSTANCE: objective lens has two components and an aperture diaphragm in between. The first component comprises a biconvex and a diverging lens and is augmented with a converging meniscus whose concave surface faces the image space and the diverging lens lying after it. The second component is a diverging meniscus whose concave surface faces the image space, made from a biconvex lens and a biconcave lens glued together and having thickness on the optical axis which is not less than 0.07 times the focal distance of the objective lens. The converging lens of the first component is made from glass with refraction index of not more than 1.5 and Abbe number of not less than 80. The distance between the components is not less than 0.13 times the focal distance of the objective lens.

EFFECT: high image quality owing to higher modulation transfer constants on the entire field of vision and keeping the length of the objective lens short.

6 dwg, 1 tbl