WIDE-APERTURE LENS Russian patent published in 2002 - IPC

FIELD: optical engineering. SUBSTANCE: device has four lenses of which the first one is positive. It has three individual lenses the first of which is meniscus turned towards the image with its con. The second one is planoconvex and turned towards the image with its plane side. The third lens is planoconcave and turned towards the object with its plane side. The fourth one is positive meniscus turned towards the object with its convex side. High quality of image is achieved when relative opening is equal to 1:1.65 with 18 deg vision field when operating in 8 to 12.5 mcm spectral bandwidth. EFFECT: high resolution of images in wide spectral range. 1 dwg