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:
Dec. 01, 2009
Filed:
Sep. 20, 2004
Takeshi Tanimoto, Saitama, JP;
Takeshi Tanimoto, Saitama, JP;
Sony Corporation, Tokyo, JP;
Abstract
In an optical pickup for irradiating a laser beam emitted from a photoemission element on a disk-like recording medium through an objective lens, there is provided a diffraction element including a first region for splitting the laser beam emitted from the photoemission element into a main beam and a pair of first sub-beams and a second region for splitting the laser into a main beam and a pair of second sub-beams, wherein a following relation hold or approximately hold: (2n−1)×P/2, where D is a distance between a spot center of the first sub-beam and a spot center of the second sub-beam, the spots being formed on a recording surface of the disk-like recording medium spaced in a substantially radial direction of the disk-like recording medium, n is a natural number, and P is a track pitch of the disk-like recording medium.