Patent ID: 6618346
Filing Date: 2003-09-09
Classification: G11B

Abstract:
An optical pickup device having a light source and an objective lens comprising:at least one of aperture restriction means that is disposed in an optical path of a light beam emitted from the light source and illuminated through the objective lens onto an optical disk, wherein the aperture restriction means has an aperture part defined by a pair of first partial arcs restricting the light beam in a radial direction of the optical disk and a pair of lines restricting the light beam in a time axis direction of the optical disk so as to make a numerical aperture of the objective lens in the time axis direction of the optical disk smaller than a numerical aperture of the objective lens in the radial direction, wherein the pair of lines of the aperture restriction means has notched parts which reduce the restriction of the cross-sectional shape of the light beam in the time axis direction of the optical disk.