An objective lens system for optical pickups reading and/or writing information
by condensing a luminous flux from a light source onto an optical information recording
medium, consists of, a single lens having, from a light source side, a first surface
convex to the light source side and a second surface convex to an image side. A
medium of the single lens is a homogeneous medium. At least one of the two surfaces
is aspherical. The system satisfies the predetermined conditions.
