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. 01, 2002
Filed:
Aug. 31, 1999
Shin-ichi Yamada, Osaka, JP;
Masayoshi Abe, Osaka, JP;
Hiroyuki Yamaguchi, Hyogo, JP;
Kouichi Takamine, Hyogo, JP;
Seiji Nishiwaki, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical disc apparatus corrects the tilting of the optical disc with a high accuracy using first and second tracking error signals. A first tracking error signal, which is an output of subtractor ( ), obtained by the push-pull method is corrected by detecting a second tracking error signal. The second tracking error signal is obtained by using the difference of amplitude of first and second signals, which are outputs of adder ( ). The first signal is obtained when the light beam passes over a first pit sequence formed in a position offset in one direction orthogonal to the track of disc ( ). The second signal is obtained when the light beam passes over a second pit sequence formed in a position offset in the other direction orthogonal to the track.