Reading lens system

Abstract

A reading lens system comprises, in order from the object side, a positive meniscus first lens element having a convex surface directed toward the object, a positive meniscus second lens element having a convex surface directed toward the object, a negative meniscus third lens element having a convex surface directed toward the object, a negative meniscus fourth lens element having a concave surface directed toward the object, a positive meniscus fifth lens element having a concave surface directed toward the object, and a positive sixth lens element. The second and third lens elements are cemented and the fourth and fifth lens elements are also cemented to provide an overall system of four-unit-six-element composition, with the lens system satisfying a number of conditions to obtain a lens having an F number of about 1:4.0 and a half viewing angle of not greater than 20.degree. and which is capable of efficient compensation for aberrations, in particular astigmatism and chromatic aberrations.

Dependencies are inferred from the claim text.