Objective lens system and optical pickup including the same

Abstract

The present invention provides an objective lens system for forming a spot of a laser beam of λ wavelength on a first information recording surface through a disc protective layer having a first thickness and a second information recording surface through a disc protective layer having a second thickness greater than the first thickness, the objective lens system including: an objective lens having at least one diffraction structure for deflecting incident light by diffraction and at least two refractive surfaces for deflecting the incident light by refraction, wherein the diffraction structure divides the incident light into m1th order diffracted light (m1 is an integer) corresponding to the first information recording surface and m2th order diffracted light (m2 is an integer different from m1) corresponding to the second information recording surface and has negative power to diverge the m2th order diffracted light.

Dependencies are inferred from the claim text.