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. 06, 2011
Filed:
Oct. 30, 2008
Atsushi Nakamura, Osaka, JP;
Kenji Fujiune, Osaka, JP;
Yasumori Hino, Nara, JP;
Panasonic Corporation, Osaka, JP;
Abstract
A method for inspecting an optical information storage medium includes irradiating the medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.