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. 09, 2008
Filed:
Feb. 06, 2006
Michiaki Shinotsuka, Hiratsuka, JP;
Hiroyuki Iwasa, Yokohama, JP;
Masaru Shinkai, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
The present invention is to provide a practically usable, recordable or rewritable optical information recording medium having a pair of recording layers and a recording and reproducing apparatus for the medium. The recording medium has a pair of recording layer structures on a substrate so as to sandwich a resin intermediate layer, and a recording beam and a reproducing beam are irradiated to two recording layer structures. The pair of recording layer structures respectively have a different track pitch, and the ratio of difference in the track pitch defined by Expression 1 is +0.03 to +0.15,(T2−T1)/T1   Expression 1 Trepresents a track pitch of the recording layer structure disposed on the laser beam irradiation side, and Trepresents a track pitch of the recording layer structure disposed on the inner side.