Patent ID: 7348529
Filing Date: 2008-03-25
Classification: G02B,G11B

Abstract:
1. An optical device for an optical pickup apparatus for recording or reproducing information with respect to an information recording medium, comprising: a hologram element divided into first and second regions having different diffraction axes and configured to diffract incident light of first and second wavelengths that are different from each other; and a light receiving element configured to receive the diffracted incident beams from the hologram element, the light receiving element comprising: diffracted beams from the first region of the hologram element originating from incident light of the first wavelength being detected by the second light receiving regions and combined into a common output, diffracted beams from the second region of the hologram element originating from the incident light of the first wavelength being detected by the second light receiving regions and combined into a common output, diffracted beams from the first and second regions of the hologram element originating from the first sub-beam of the second wavelength being detected by the second light receiving regions and combined into a common output, diffracted beams from the first and second regions of the hologram element originating from the second sub-beam of the second wavelength being detected by the second light receiving regions and combined into a common output.