The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 21, 2002
Filed:
Dec. 13, 1999
Nobuhiko Ando, Tokyo, JP;
Kazuhiko Fujiie, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical pickup device that is able to record/reproduce information signals for first and second optical discs with different recording capacities. The optical pickup device includes an objective lens for converging first and second light beams of different wavelengths on the signal recording layers of first and second optical discs having different substrate thicknesses, a beam splitter having the same transmittance to the first and second light beams and configured for separating the first and second light beams radiated by first and second light sources to fall on the beam splitter via a first objective lens or a second objective lens, and a hologram element arranged between the objective lens and the beam splitter for limiting the aperture of one of the first light beam and the second light beam and for correcting the spherical aberration caused by difference in the disc substrate thickness of the first and second optical discs. This configuration enables various optical elements, such as objective lens or beam splitter, to be used in common for the optical disc of different recording capacities.