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. 16, 2012
Filed:
Mar. 18, 2011
Hiromitsu Mori, Fujisawa, JP;
Hiromitsu Mori, Fujisawa, JP;
Hitachi Media Electronics Co., Ltd., Iwate, JP;
Abstract
The relation between the cover layer thickness of a data recording surface and ratio α of SCO to SCD is previously calculated and stored in a storage unit, where SCD denotes coma aberration which occurs when the data recording medium is tilted by unit angle and SCO denotes coma aberration which occurs when the objective lens is tilted by unit angle. When αdenotes ratio α for a data recording surface corresponding to the smallest cover layer thickness, tilting angle θof the objective lens is determined based on the αand a tilt adjustment of the objective lens is made. Also, when αdenotes ratio α for a target data recording surface, tilting angle θof the objective lens is estimated based on the ratio of αto αand a tilt correction of the objective lens is made.