Patent ID: 6181667
Filing Date: 2001-01-30
Classification: G11B

Abstract:
An optical pickup apparatus comprising:a light source for emitting a beam;a first diffraction element having a diffraction surface for diffracting said beam emitted form said light source at least in first and second directions; andan objective lens for irradiating an optical recording medium with beams diffracted by said first diffraction element in said first and second directions;wherein the width of said diffraction surface of said first diffraction element in a plane including the optical axis of said beam emitted from said light source and axes of said beams diffracted in said first and second directions is set to be smaller than the width of region including a first light spot and a second light spot,said first light spot being a light spot on said first diffraction element corresponding to a part of said beam, diffracted by said first diffraction element in said first direction, entering said objective lens in said beam emitted from said light source, andsaid second light spot being a light spot on said first diffraction element corresponding to a part of said beam, diffracted by said first diffraction element in said second direction, entering said objective lens in said beam emitted from said light source,wherein said diffraction surface of said first diffraction element is formed on a position passing the optical axis of said beam emitted from said light source there through.