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:
Aug. 04, 2009
Filed:
Oct. 26, 2007
Akihiro Asada, Chigasaki, JP;
Masaaki Kurebayashi, Ebina, JP;
Akihiro Asada, Chigasaki, JP;
Masaaki Kurebayashi, Ebina, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi-LG Data Storage, Inc., Tokyo, JP;
Abstract
An optical disk drive includes drive current generation unit for supplying a mark forming semiconductor laser drive current and a space forming semiconductor laser drive current; first high-frequency superimposition unit for superimposing a high-frequency component on the space forming semiconductor laser drive current; and high-frequency superimposition control unit for controlling the first high-frequency superimposition unit to stop the superimposition of the high-frequency component for a predetermined duration prior to a timing at which to switch from the space forming semiconductor laser drive current to the mark forming semiconductor laser drive current, eliminating positional variations on the disk of the mark leading and trailing edges due to the high frequency superimposition.