| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disk of a land-and-groove recording system capable of narrowizing a track pitch while suppressing the drop of an S/N ratio of reproduction signals. <P>SOLUTION: In the optical disk which includes guide groove portions G and space portions L between the groove portions and is loaded to an optical disk recording/reproduction apparatus having a mechanism for removing or reducing leakage signals from adjacent tracks by using three or more light beam spots and wherein signals are recorded to the groove portions G and the space portions L between the groove portions, depth d of the groove portions G is specified to be ≥λ/12n and <λ/6n, when a wavelength of reproduction light emitted from the optical disk recording/reproduction apparatus and a refractive index of a cover layer 16 on an incidence side of reproduction light or a substrate 11 are defined as λ and n, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
