OBJECTIVE LENS, OPTICAL PICKUP APPARATUS AND OPTICAL INFORMATION RECORDING AND/OR REPRODUCING APPARATUS

摘要

An objective lens according to the present invention is an objective lens used for an optical pickup apparatus, and the objective lens includes a superimposed structure on a surface of a lens with a power in which a first optical path difference providing structure changing spherical aberration in under-corrected direction when a wavelength of an incident light flux becomes longer, and a second optical path difference providing structure changing spherical aberration in over-corrected direction when a wavelength of an incident light flux becomes longer are superimposed.