Objective lens, reproducing apparatus and reproducing method

摘要

An objective lens, a reproducing apparatus and a reproducing method using a single objective lens for a DVD which can also read a CD without adding any peripheral member can be obtained. In an objective lens which is arranged so that a light beam emitted from a common light source (11) may be focused through a common objective lens (8) on respective signal recorded surfaces (la), (2a) of a DVD (2) and a CD (1) having light transmitting layers (1c), (2c) of different thicknesses, an area of the objective lens (8) for the DVD (2) in a range of a numerical aperture NA from 0 to 0.3-0.4 from the light axis is worked to form correcting lens surface (8a) for correcting the aberration caused when reading the CD (1) through the objective lens for the DVD (2), thereby allowing the CD to be read through the objective lens for the DVD. <IMAGE>