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:
Mar. 21, 2006
Filed:
Mar. 27, 2002
Applicant:
Osamu Hamaoka, Yamatotakada, JP;
Inventor:
Osamu Hamaoka, Yamatotakada, JP;
Assignee:
Sharp Kabushiki Kaisha, Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/13 (2006.01);
U.S. Cl.
CPC ...
Abstract
An optical pickup comprises a light source, a three-way split light diffracting section for dividing light emitted from a light source into one main beam and two subbeams, a hologram for dividing each of the main beam and the subbeams reflected from a recording medium into two predetermined directions, and a light receiving section for receiving the beams divided by the hologram. The hologram includes two regions having a small-pitch grating for diffracting each beam to a predetermined direction, the small-pitch gratings have substantially the same pitch and are symmetrical about a split line separating the two regions.