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. 08, 2013
Filed:
Mar. 15, 2012
Takashi Usui, Saitama, JP;
Kazuo Watabe, Yokohama, JP;
Hideaki Okano, Yokohama, JP;
Chikara Tanioka, Yokohama, JP;
Akihito Ogawa, Fujisawa, JP;
Kazuaki Doi, Kawasaki, JP;
Takashi Usui, Saitama, JP;
Kazuo Watabe, Yokohama, JP;
Hideaki Okano, Yokohama, JP;
Chikara Tanioka, Yokohama, JP;
Akihito Ogawa, Fujisawa, JP;
Kazuaki Doi, Kawasaki, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A focus servo control device includes a first detector, first controller, second detector, and second controller. The first detector detects a first focus error signal. The first controller controls the objective lens based on the first focus error signal, so that a focal point of the first laser agrees with the guide layer. The second detector detects a second focus error signal. The second controller changes a relative distance between the focal point of the second laser and the focal point of the first laser, so that the focal point of the second laser agrees with a target recording/reproducing layer.