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.:

US 8040779 B1

PDF
Full Text
Expired
Date of Patent:
Oct. 18, 2011

Filed:

Jul. 27, 2010
Applicants:

Kenji Nagatomi, Kaizu, JP;

Katsutoshi Hibino, Kaizu, JP;

Inventors:

Kenji Nagatomi, Kaizu, JP;

Katsutoshi Hibino, Kaizu, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/135 (2006.01);
U.S. Cl.
CPC ...
Abstract

An optical pickup device includes an astigmatism element which sets focal line positions to be defined by convergence of laser light away from each other, a diffraction element which diffracts four light fluxes obtained by a light flux of the laser light to disperse the four light fluxes from each other, and a photodetector having a first sensing section and a second sensing section which respectively receive m-th order diffraction light and n-th order diffraction light of the four light fluxes. In this arrangement, the first sensing section receives eight light fluxes obtained by dividing the four light fluxes of the m-th order diffraction light by two straight lines to output detection signals of the number less than eight.


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Nagatomi, Kenji. (2011). Optical pickup device and optical disc device (U.S. Patent No. 8040779). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/8040779

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