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US 6,618,346 B1Granted
Optical pickup device having aperture restriction arrangement
AssigneePioneer Corporation
InventorsTakanori Maeda, Takayuki Nomoto
Life of this patent
Estimating the term…
Abstract
An optical pickup device has one or a plurality of aperture restriction devices that are disposed in the optical path of a light beam that is emitted from a light source and illuminated onto an optical disk. The aperture restriction device restricts the cross-sectional shape of the light beam corresponding to the aperture in the time axis direction in comparison to that corresponding to the aperture in the radial direction and restricts the light beam in the radial direction of the optical disk by a pair of first partial arcs.
Claims3
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.
1 more element
Dependencies are inferred from the claim text.