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:
Jul. 03, 2001
Filed:
Mar. 10, 1999
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
When a disc is driven at a low speed, the number of tracks crossed by a beam spot of an optical pickup (3) is determined as the number of crossing tracks corresponding to an amount of mass eccentricity of the disc. If this number of crossing tracks exceeds a first threshold value, the disc is rejected as a non-conforming disc. When the disc is driven at a high speed, the number of tracks crossed by the beam spot is determined, a value remaining by subtracting the number of crossing tracks at the low speed from the number of crossing tracks at the high speed is determined as an amount of vibration produced owing to a mass eccentricity of the disc. Thus, a disc drive which can make an extremely precise detection of a magnitude of vibration resulting from the mass eccentricity of the disc without using a sensor component for detecting the vibration can be provided.