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:
Sep. 01, 2009
Filed:
Jun. 20, 2005
Hiroaki Yukawa, Kanagawa, JP;
Midori Kanaya, Tokyo, JP;
Hiroaki Yukawa, Kanagawa, JP;
Midori Kanaya, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical pickup includes a diffracting element having a plurality of regions for dividing the laser light emitted from the light-emitting element into a main beam and pairs of first, second, third, and fourth sub-beams. When the first to fourth sub-beams form first to fourth sub-spots, respectively, in that order along a radial direction on a recording surface of an arbitrary kind of disc-shaped recording medium which does not have the largest track pitch, n is a natural number, and the track pitch is Pa, the distance Dabetween the first and second sub-spots is approximately (2n−1)×Pa/2, the distance Dabetween the third and fourth sub-spots is approximately (2n−1)×Pa/2, the distance Dabetween the first and third sub-spots is approximately (2n−1)×Pa, and the distance Dabetween the second and fourth sub-spots is approximately (2n−1)×Pa.