Patent ID: 6577456
Filing Date: 2003-06-10
Classification: G02B

Abstract:
A single focus lens formed of only two lens groups, in order from the object side, as follows:a first lens group formed of only a single lens of positive refractive power, with at least one of its surfaces aspherical; and a second lens group formed of only a single lens element of positive refractive power, with at least one of its surfaces aspherical and having a convex surface on the object side; wherein the following Conditions are satisfied: &ugr;d2>50 |f/f1|<0.75 â€ƒwhere &ugr;d2 is the Abbe number, at the d line, of the lens element that forms the second lens group, f is the focal length of the single focus lens, and f1 is the focal length of the lens that forms the first lens group.