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:
Nov. 04, 2003
Filed:
Mar. 06, 2002
Applicant:
Inventors:
Hitoshi Furuhata, Tokorozawa, JP;
Tomotaka Nishimura, Tokorozawa, JP;
Assignee:
Pioneer Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/00 ;
U.S. Cl.
CPC ...
G11B 7/00 ;
Abstract
An optical pickup apparatus which, assuming that a distance from a first light source to a first grating is a, a distance from a second light source to a second grating is b, a first predetermined grating pitch is I, a second predetermined grating pitch is J, the wavelength of a first laser beam is &lgr; , and the wavelength of a second laser beam is &lgr; , satisfies &lgr; >(I·b)/(J·a), and which is capable of preventing a drop in the level of a tracking error signal resulting from decentering of an optical recording medium, even in the case of using either of optical recording media of different recording densities.