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:
Oct. 11, 2005
Filed:
Apr. 01, 2002
Applicants:
Hajime Nishimura, Hitachinaka, JP;
Yoshihiro Fukagawa, Yokohama, JP;
Seiji Inaba, Hitachinaka, JP;
Inventors:
Assignee:
Hitachi-LG Data Storage, Inc., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B009/00 ;
U.S. Cl.
CPC ...
Abstract
A drive current or a drive voltage is controlled corresponding to change of load by sampling the drive current or drive voltage of a motor to move an optical pickup and then detecting change of the sampling signal as change of the optical pickup when it is moved. Moreover, change of the sampling signal is obtained from a difference of the sampling signals by comparing these sampling signals at the first and second points. Comparison of these sampling signals is conducted in unit of drive pulse.