Multiple focal lens, multiple focal optical pickup and optical information reproducing apparatus

摘要

A multiple focal lens (10) is provided with: a diffraction element (H) having a light incident surface (HI) and a light outgoing surface for diffracting a light beam (L) incident from the external to the light incident surface and generating a plurality of diffraction light beams (L0, L+1, L-1) from the light outgoing surface; a light condense element (R) for condensing the generated diffraction light beams respectively onto a plurality of focal points different in position from each other; and a main body (10a) for holding said diffraction element and said light condense element. A central axis (CH) of said diffraction element and a central axis (CR) of said light condense element are offset to each other such that one optical path of one reflection light (L0), which is used for reproducing information, among a plurality of reflection lights of the condensed diffraction light beams reflected from an information record medium (1, DVD) on which the information to be reproduced is recorded, and the other optical paths of the other reflection lights (L+1, L-1) among the plurality of reflection lights are offset to each other. IMAGE