| US 7,507,523 B2 | ||
| Optical information recording medium, method of manufacturing the optical information recording medium, and method of and apparatus for recording/reproducing optical information | ||
| Katsuyuki Yamada, Kanagawa (Japan); Shinya Narumi, Kanagawa (Japan); Makoto Harigaya, Kanagawa (Japan); Katsuhiko Tani, Tokyo (Japan); Noriyuki Iwata, Kanagawa (Japan); Nobuaki Onagi, Kanagawa (Japan); Kazunori Ito, Kanagawa (Japan); Takashi Shibaguchi, Kanagawa (Japan); Eiko Hibino, Kanagawa (Japan); Hajime Yuzurihara, Kanagawa (Japan); Hiroko Ohkura, Kanagawa (Japan); Akira Shimofuku, Kanagawa (Japan); and Yuki Nakamura, Kanagawa (Japan) | ||
| Assigned to Ricoh Company, Ltd, Tokyo (Japan) | ||
| Filed on Sep. 28, 2001, as Appl. No. 9/966,171. | ||
| Claims priority of application No. 2000-297364 (JP), filed on Sep. 28, 2000; application No. 2000-310536 (JP), filed on Oct. 11, 2000; application No. 2000-367361 (JP), filed on Dec. 01, 2000; and application No. 2001-088516 (JP), filed on Mar. 26, 2001. | ||
| Prior Publication US 2002/0110063 A1, Aug. 15, 2002 | ||
| Int. Cl. G11B 7/24 (2006.01) | ||
| U.S. Cl. 430—270.13 [430/945; 428/64.8; 369/275.2; 369/275.4] | 33 Claims |

| 1. An optical information recording medium comprising:
a transparent substrate having a concentric circular guide groove or a spiral guide groove, said guide groove having land
portions and groove portions formed thereon; and
a phase change type recording layer on said transparent substrate;
wherein information that indicates a standard recording linear velocity Vr and/or a maximum recording linear velocity Vh is
stored on the medium, said stored information being recorded onto said substrate;
wherein, while irradiating on land portions or groove portions formed on said guide groove energy enabled to melt the material
of said phase change type recording layer and while increasing a linear velocity of said medium and scanning, the linear velocity
at which the reflectivity of said optical information recording medium decreases, in comparison to that before the energy
is radiated, is defined as uppermost recrystallization linear velocity V;
wherein the uppermost recrystallization linear velocity V at the time when a focused semiconductor beam irradiates said groove
portions or land portions of said guide groove satisfies a relation, the focused semiconductor beam being used for recording
or reproducing,
V≧Vr×0.85
or
V≧Vh×0.85; and
wherein a track pitch of said guide groove is between 0.2 and 1.4 μm, and the uppermost recrystallization linear velocity
V is between 16 and 24 m/s.
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