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:
Feb. 06, 2001
Filed:
Jun. 30, 1998
Akihiro Arai, Souraku-gun, JP;
Takao Hayashi, Toyonaka, JP;
Tohru Nakamura, Katano, JP;
Takayuki Nagata, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical head is composed of an objective,a composite diffraction element,having six areas divided by three parting lines,to,and a substrate,on which a light-emitting element and a plurality of light-receiving elements are arranged. A focus and a tracking error signals are generated based on signals from the light-receiving elements that receive those of a plurality of luminous fluxes divided by the composite diffraction element,which result from passage through the portion between the parting lines,and,In generating the tracking error signal, signals from the light-receiving elements that receive luminous fluxes resulting from passage through the outside of the parting lines,and,are used to correct an offset in the tracking error signal caused by the movement of the objective.