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. 21, 2008
Filed:
Nov. 26, 2003
Katsuya Watanabe, Nara, JP;
Shin-ichi Yamada, Katano, JP;
Kenji Fujiune, Takatsuki, JP;
Yuuichi Kuze, Settsu, JP;
Katsuya Watanabe, Nara, JP;
Shin-ichi Yamada, Katano, JP;
Kenji Fujiune, Takatsuki, JP;
Yuuichi Kuze, Settsu, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical disc drive includes: a light source; a focusing section; a focus shifting section for shifting the focal point of light by changing the position of the focusing section perpendicularly to a data storage layer of a given optical disc in accordance with a control signal; a light receiving section for receiving, at multiple areas, the light reflected from the data storage layer and generating light quantity signals; a signal generating section for generating a focus error signal based on the light quantity signals; and a control section for generating the control signal responsive to the focus error signal such that the focal point is transferred to a focus controllable range. The control section generates the control signal such that the focal point is decelerated at a first acceleration and then at a second acceleration. The absolute value of the second acceleration is smaller than that of the first acceleration.