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. 07, 2012
Filed:
Apr. 16, 2008
Koji Mishima, Tokyo, JP;
Tsutomu Aoyama, Tokyo, JP;
Takashi Kikukawa, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
An optical recording medium which includes three or more information layers and has a higher stack density of information layers than before in the direction of thickness while reducing crosstalk during reproduction, and a method for reading the optical recording medium are provided. The optical recording medium has a three-layer structure which includes a substrate, a first information layer, a first spacer layer, a second information layer, a second spacer layer, a third information layer, and a cover layer thinner than the substrate, with these layers being stacked in that order over the substrate, wherein the following Equation (I) is satisfied:()/≦0.0032  Equation (I)where Ris the reflectivity of the first information layer, Ris the reflectivity of the second information layer, and Ris the reflectivity of the third information layer, and the first spacer layer and the second spacer layer are equal to each other in thickness.