| 摘要 |
An optical pickup and an optical data processing device using the same are provided to correct inter-layer confusion without influence about the spot concentrated on the recording side of an optical recording medium when an optical axis difference occurs according to the driving of the objective lens. An optical pickup comprises a light source, a light collecting unit, a diffraction element(2), a branch optical element, a 1/4 wave plate(8), a light receiving unit, and a correcting element. The correcting element is divided into at least two areas in the vertical plane of the optical axis. The area of the correcting element includes a sub-wavelength concavo-convex structure having a shorter period than the wavelength of incident light. In the sub-wavelength concavo-convex structure, groove directions of the adjacent areas intersect at right angle. The filling of the sub-wavelength concavo-convex structure is determined so that for the phase difference between the adjacent areas is pi to the polarization direction perpendicular to the polarization direction of the light emitted from the light source.
|
