OPTICAL PICKUP APPARATUS, OBJECTIVE OPTICAL ELEMENT, AND OPTICAL INFORMATION RECORDING AND REPRODUCING APPARATUS

摘要

Provided are an optical pickup apparatus, an objective optical element, and an optical information recording and reproducing apparatus, capable of recording and/or reproducing information in a compatible way to different types of optical discs. The optical pickup apparatus comprises a first light source that emits a first light flux, a second light source that emits a second light flux, a third light source that emits a third light flux, and an objective optical element. The optical surface of the objective optical element has at least two areas of a central area and a peripheral area surrounding the central area, wherein the central area has a first optical path difference giving structure and the peripheral area has a second optical path difference giving structure. The objective optical element focuses the light fluxes passing through its central and peripheral areas on the information recording surfaces of respective prescribed optical discs so that the information can be recorded and/or reproduced. The first optical path difference giving structure is formed by superimposing a first basic structure and a second basic structure having respective predetermined structures on each other.