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:
Jun. 02, 2009
Filed:
Dec. 03, 2003
Junichiro Tonami, Yokohama, JP;
Junichiro Tonami, Yokohama, JP;
Victor Company of Japan, Limited, Yokohama, Kanagawa-ken, JP;
Abstract
An optical disk unit capable of correcting a spherical aberration without using special patterns is provided. Also provided is an aberration correcting method used for such an optical disk unit. An objective lensis moved along an optical axis by a predetermined distance from an in-focus position in a first direction, and then, is moved by the predetermined distance from the in-focus position in a second direction that is opposite to the first direction. In each of the objective lens moved states, a random signal having a plurality of amplitudes and periods is reproduced from an optional area of an information recording layerof an optical diskA servo circuitextracts a specific portion having a specific amplitude or period from the reproduced random signal in each of the objective lens moved states, finds a first amplitude value and second amplitude value in the specific portions, and controls an aberration correctorso that the difference between the first amplitude value and the second amplitude value approaches zero.