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:
Apr. 17, 2012

Filed:

Oct. 17, 2003
Applicants:

Soo-han Park, Yongin-si, KR;

Jong-uk Kim, Yongin-si, KR;

Inventors:

Soo-han Park, Yongin-si, KR;

Jong-uk Kim, Yongin-si, KR;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/095 (2006.01);
U.S. Cl.
CPC ...
Abstract

A photodetector detecting reflected light components from an optical medium, the photodetector including a first detector divided into eight sections detecting the reflected light components and converting the light components into electrical signals, a first calculating portion calculating a first tracking error signal from the electrical signals by a differential push-pull method, a second calculating portion calculating a first focusing error signal by an astigmatism method and calculating a second tracking error signal by a differential phase detection method from the electrical signals converted by the first detector; a second detector divided into four sections detecting the reflected light components reflected by the optical recording medium to convert the light components into electrical signals; and a third calculating portion calculating a second focusing error signal by the astigmatism method and calculating a third tracking error signal by the differential phase detection method from the electrical signals converted by the second detector.


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