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:
Apr. 25, 1995
Filed:
Mar. 01, 1993
Applicant:
Inventors:
Yukio Kurata, Tenri, JP;
Yukinori Nishitani, Neyagawa, JP;
Yoshio Yoshida, Tenri, JP;
Takahiro Miyake, Tenri, JP;
Assignee:
Sharp Kabushiki Kaisha, Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369109 ; 369116 ;
Abstract
An optical pickup apparatus for reading out information from an optical disk. The optical pickup includes a light source; and an optical device having a grating pattern for splitting a light beam from said the source into a zero-order diffracted beam and plus and minus first-order diffracted beams. The grating pattern has the center portion and one or more side portions. The efficiency of the center portion for the zero-order diffracted beam is greater than the efficiency of the side portions for the zero-order diffracted beam.