Objective lens, and optical pickup device using the objective lens

摘要

An objective lens unit used for an optical pickup device is made up of a plurality of lenses and has a numerical aperture (NA) not less than 0.7. The lenses ( 1 ) and ( 2 ) are secured within a cylindrically-shaped lens holder ( 3 ). The position of the lens(es) ( 2 ) other than one of the lenses secured within the lens holder is set with the position of the one lens ( 1 ) as reference.