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:
Nov. 09, 2010
Filed:
Feb. 08, 2008
Isao Matsuda, Gunma, JP;
Fumi Hara, Gunma, JP;
Takeshi Otsu, Gunma, JP;
Motomitsu Hagiwara, Gunma, JP;
Akimasa Miyata, Gunma, JP;
Isao Matsuda, Gunma, JP;
Fumi Hara, Gunma, JP;
Takeshi Otsu, Gunma, JP;
Motomitsu Hagiwara, Gunma, JP;
Akimasa Miyata, Gunma, JP;
Taiyo Yuden Co., Ltd., Tokyo, JP;
Abstract
An optical information recording medium having a disk-shaped substrate formed with spiral grooves on one main surface, and having an optical reflection layer formed with grooves at the surface corresponding to the grooves of the substrate for reflecting a laser beam, an optical recording layer, a protective layer, and an optical transparency layer in this order on the main surface thereof. The optical information recording medium has a main information area and a sub-information area to the inner circumferential side thereof, in which the track pitch TrB of the grooves in the sub-information area is about 0.32 μm or less, and the depth D of the grooves and the half-band width W of the grooves satisfy a relation represented by: W≧2D+70, whereby the difference between the reflectivity at the land surface and the reflectivity at the groove surface in the sub-information area can be restricted to less than 30%, thereby preventing occurrence of mis-decipherment for BCA marks.