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:
Jan. 21, 2014
Filed:
Mar. 02, 2012
Seiji Imagawa, Yokohama, JP;
Seiji Imagawa, Yokohama, JP;
Hitachi-LG Data Storage, Inc., Tokyo, JP;
Hitachi Consumer Electronics Co., Ltd., Tokyo, JP;
Abstract
The operability of an optical disc device for reading or writing data from/to a disc having a data layer and a servo layer is improved by increasing the resistance to control disturbances. An optical disc device in accordance with the present invention includes an objective lens, a relay lens, a blue-violet laser detector, a red laser detector, an objective lens focus actuator, an objective lens tracking actuator, a relay lens actuator, a pair of focus error signal generating units, a pair of focus control signal generating units, a switching unit for selecting a focus control signal, a pair of tracking error signal generating units, a pair of tracking control signal generating units, a switching unit for selecting a tracking control signal, a focus error conversion unit and a tracking error conversion unit.