Patent ID: 6034825
Filing Date: 2000-03-07
Classification: G02B

Abstract:
An objective lens system comprising:a first lens unit comprising a cemented lens component which comprises a plurality of radial type gradient index lens elements having refractive indices varying dependently on distances as measured from an optical axis as expressed by the formula (a) shown below,wherein one of the radial type gradient index lens elements is disposed on the object most side beyond which there is no lens element of said objective lens system, and the radial type gradient index lens disposed on the object most side has a concave surface on the object side, andN(r)=N.sub.00 +N.sub.10 r.sup.2 +N.sub.20 r.sup.4 + (a)wherein said objective lens system emits parallel rays, andwherein the reference symbol r represents a distance as measured from the optical axis in a radial direction, the reference symbol N.sub.00 designates a refractive index on the optical axis, and the reference symbols N.sub.10, N.sub.20, . . . denote coefficients of the second, fourth, . . . orders, respectively.