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:
Dec. 20, 2011
Filed:
Jan. 27, 2009
Koji Mishima, Tokyo, JP;
Hiroyasu Inoue, Tokyo, JP;
Takashi Kikukawa, Tokyo, JP;
Tetsuya Nishiyama, Tokyo, JP;
Koji Mishima, Tokyo, JP;
Hiroyasu Inoue, Tokyo, JP;
Takashi Kikukawa, Tokyo, JP;
Tetsuya Nishiyama, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
A multilayer optical recording medium having three or more information recording layers is irradiated with a laser beam, and a first signal obtained from the reflected laser beam is subjected to a frequency filter. A second signal obtained by filtration through a high-pass filter is used to evaluate the characteristics of the multilayer optical recording medium. In this manner, even in a multilayer optical recording medium having three or more information recording layers, the influence of the variation of the thickness and material of the information recording layers and the influence of the variation of the thickness of a spacer layer can be clearly determined and evaluated.