Imaging lens

Abstract

Successively from an object side, a stop, a biconvex lens, a biconcave lens, a biconvex lens, and a meniscus lens having a convex surface directed onto the image side are disposed, while the image-side surfaces of the second and third lenses are set to have a predetermined range of power, thereby favorably correcting various kinds of aberration, such as distortion in particular, while reducing the size of the whole lens system. Disposed successively from the object side are a stop i, a first lens L.sub.1 made of a biconvex lens, a second lens L.sub.2 made of a biconcave lens, a third lens L.sub.3 made of a biconvex lens, and a fourth lens L.sub.4 made of a meniscus lens having a convex surface directed onto the image side. These lenses satisfy the following conditional expressions : 0.4<R.sub.5/ f<2.0 0.4<.vertline.R.sub.7 .vertline./f<2.2 wherein R.sub.5 is a radius of curvature of the surface of the second lens on the image side; R.sub.7 is a radius of curvature of the surface of the third lens on the image side; and f is a composite focal length of the whole system.

Dependencies are inferred from the claim text.