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:
Jun. 07, 2011
Filed:
Nov. 13, 2008
Applicants:
Ryutaro Futakuchi, Osaka, JP;
Masahiro Birukawa, Osaka, JP;
Inventors:
Ryutaro Futakuchi, Osaka, JP;
Masahiro Birukawa, Osaka, JP;
Assignee:
Panasonic Corporation, Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 7/004 (2006.01);
U.S. Cl.
CPC ...
Abstract
A gap controller according to the present invention can set a reference level reasonably for a gap control that needs to be done to keep the gap between a solid immersion lens (SIL) and an optical disc constant. With the gap varied at a substantially regular step, gap detection signal levels are logged to find an extreme value of its second-order difference. And the gap control reference level is determined by the gap detection signal level that results in that extreme value.