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:
Sep. 04, 2012
Filed:
Sep. 20, 2011
Yoshiaki Komma, Osaka, JP;
Joji Anzai, Osaka, JP;
Yoshiaki Komma, Osaka, JP;
Joji Anzai, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An optical recording medium (disk) capable of preventing a back focus at a face thereof and reducing the interference between beams reflected by each recording surface, thereby improving a quality of a servo signal and a reproductive signal. In a disk having (N−1) layers, if N is a natural number (more than three), and if a cover-layer thickness and intermediate-layer thicknesses are d, d, . . . dN, then a difference of 1 μm or above is set between the sum of di to dj and the sum of dk to dm for arbitrary natural numbers i, j, k, m (i≦j≦k≦m≦N). If refractive indexes are different from a standard value or different for each layer, then the thickness of each layer is converted based on a spread width of light according to the thickness.