OBJECTIVE Russian patent published in 2007 - IPC G02B9/18 G02B13/14 

FIELD: optics.

SUBSTANCE: objective has two serial components disposed in the direction of paths of beams. First component has to be positive one made of two glued lenses; one lens is biconvex and the other one is negative concave flat lens. Second component is made of two singular lenses, namely, negative meniscus which is turned with its concavity to object and convex flat lens disposed behind negative meniscus. There can be prism or prisms either flat parallel plate or plates between singular lenses of second component. Relations among width of second air gap, focal length of whole objective, radiuses of second, fourth and fifth optical surfaces, thickness of third lens and refractivity factors and dispersion coefficients for line d of materials of lenses are given in description of invention. Air gap between third and fourth lenses in increased to give ability of installing additional optical members.

EFFECT: increased relative aperture; higher adaptability to manufacture; higher quality of image.

5 cl, 2 dwg