WIDE APERTURE LENS IN EXTENDED ENTRANCE PUPIL Russian patent published in 1999 - IPC

FIELD: optical instruments, in particular, design of black-and-white CCD matrix cameras. SUBSTANCE: device has two members, first of which is designed as positive meniscus which concave surface is directed to objects. Second member is designed as positive lens, which is glued from biconvex lens and negative meniscus. Ratio of sum of meniscus width and distance from entrance pupil to absolute values of first and second radiuses is respectively in range of 0.80 to 0.78. Focal length of second glued member is equal to absolute value of focal length of negative meniscus. In addition first meniscus may be produced from two menisci which radiuses are of same sign or from two lenses, one of which is biconvex and another is biconcave. Second member may be produced from glued triplet in which two biconcave lenses are located at edges and biconvex lens is in center. EFFECT: increased aperture while keeping high resolution and relative aperture, increased aberration correction capacity. 21 cl, 10 dwg