| 摘要 |
PROBLEM TO BE SOLVED: To obtain a large-capacity optical memory medium, more particularly a magneto-optical recording medium. SOLUTION: This optical recording medium for executing recording or reproducing by irradiation with a laser beam from a substrate side and has concentric or spiral tracking lands and grooves disposed as recording regions. The group depth Dg and the groove width Wg satisfy the following relations: The equations are; Wg/ϕ>=0.454, Wg/ϕ>=2.38Dg/(λ/n)+0.068, Wg/ϕ<=1.20Dg/(λ/n)+0.363, Wg/ϕ<=-1.53Dg/(λ/n)+0.797, Dg/(λ/n)>=0.125, Wg/ϕ<=0.539, Wg/ϕ<=2.76Dg/(λ/ n)+0.148. In the formulas, λ denotes the wavelength (in the air) of reproducing light; n denotes the refractive index of the substrate and ϕ denotes the spot diameter of the reproducing light. |
