OPTICAL PICKUP DEVICE AND OBJECTIVE OPTICAL ELEMENT

摘要

An optical pickup device which can satisfactorily record and/or reproduce information on different kinds of optical information recording mediums in spite of compactness, and an objective optical element used for the optical pickup device. The optical function surface of the objective optical element has at least two areas of a central area including an optical axis and a surrounding area surrounding the central area. An optical path difference impartation structure in the central area is a structure obtained by superimposing a first central fundamental structure and a second central fundamental structure which are orbicular and zonal structures separated from each other by a level difference on each other. The optical path difference impartation structure in the surrounding area is a structure obtained by superimposing a first surrounding fundamental structure and a second surrounding fundamental structure which are orbicular and zonal structures separated from each other by a level difference on each other.