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.

Date of Patent:
May. 20, 2003

Filed:

Jan. 19, 2000
Applicant:
Inventors:

Wataru Kubo, Saitama-ken, JP;

Hiroshi Nishikawa, Saitama-ken, JP;

Masato Noguchi, Saitama-ken, JP;

Assignee:

Pentax Corporation, Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/135 ; G11B 7/095 ;
U.S. Cl.
CPC ...
G11B 7/135 ; G11B 7/095 ;
Abstract

An optical head is provided with a beam splitting element which divides a beam reflected by a data recording surface of an optical disc into two beams with generating opposite defocus therebetween, and a pair of light receiving elements which receive the two beams divided by the beam splitting element, respectively, the pair of light receiving elements being arranged substantially on a same plane. A light receiving surface of each of the pair of light receiving elements is divided, by two lines extending in a direction corresponding to a tracking direction on the optical disc, into at least three light receiving areas. A focusing error signal is generated in accordance with outputs of the at least three light receiving areas.


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