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:
Sep. 30, 1997
Filed:
Jun. 07, 1996
Applicant:
Inventors:
Sakashi Ootaki, Tsurugashima, JP;
Ryo Sato, Tsurugashima, JP;
Assignee:
Pioneer Electronic Corporation, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369112 ; 369 4423 ; 369 4432 ;
Abstract
An optical pickup device which makes a numerical aperture of an object lens in a radial direction of an optical disk smaller than that in a tangential direction to a track on the optical disk. With this feature, a spot diameter in the tangential direction to the track becomes smaller than that in the radial disk in the data recorded surface thereof, and it is possible to prevent degradation of a MTF as well as to accurately read data recorded in the high-density optical disk.