| 摘要 |
PURPOSE:To obtain the DRAW type optical disk having good playability by providing a specific relation between the potentials of land parts, groove parts and specular surface parts. CONSTITUTION:A light absorption layer 12 and a light reflection layer 13 are provided on a substrate 11. The annular specular parts 31, 35 are formed in the parts where the reflection layer 13 and the substrate 11 come into direct contact. Since pregrooves 70 are formed on the substrate 11, the groove parts 41 and the land parts 51 exist according to the presence or absence thereof. The optical disk constituted in such a manner is so designed that the value defined by an RMI value=(Il-Ig)/Io attains >=0.22 when the potentials of the land parts 51, the groove parts 41 and the specular mirror parts 31, 35 are respectively designated as Ii, Ig Io. This RMI value is regulated by the depth, width and shape of the grooves, the thickness and optical constant of the absorption layer 12, the shape of the boundary between the absorption layer 12 and the reflection layer 13 and the material quality of the substrate 11, etc. |
