| US 7,540,006 B2 | ||
| Optical information recording medium and manufacture method thereof | ||
| Ken'ichi Nagata, Nishinomiya (Japan); Kenichi Nishiuchi, Hirakata (Japan); Hideki Kitaura, Souraku-gun (Japan); Hideo Kusada, Osaka (Japan); Noboru Yamada, Hirakata (Japan); and Shinya Abe, Kadoma (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Appl. No. 10/567,356 PCT Filed Aug. 05, 2004, PCT No. PCT/JP2004/011239 § 371(c)(1), (2), (4) Date Mar. 06, 2006, PCT Pub. No. WO2005/015555, PCT Pub. Date Feb. 17, 2005. |
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| Claims priority of application No. 2003-288787 (JP), filed on Aug. 07, 2003. | ||
| Prior Publication US 2006/0146685 A1, Jul. 06, 2006 | ||
| Int. Cl. G11B 7/24 (2006.01) | ||
| U.S. Cl. 720—718 [369/275.4; 369/277; 369/278; 369/279] | 8 Claims |
| 1. An optical information recording medium comprising:
one or more information layers including a recording layer for recording/reproducing an information signal by irradiation
with a laser light; and
a separating layer or a protective substrate on which a first information layer of the information layer on the irradiation
face side is formed,
the separating layer or the protective substrate having a guide groove spirally or concentrically formed on a surface thereof,
respective inclined planes on the inner perimeter side and the outer perimeter side of the guide groove having inclined angles
α and β with respect to a bottom face of the guide groove,
the guide groove having two or more dissymmetric regions in the radius direction where the inclined angles α and β are different,
wherein the dissymmetric regions comprise first and second dissymmetric regions having the following relations: α-β≤10 degrees
in the first dissymmetric region, and α-β≧20 degrees in the second dissymmetric region.
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