| 摘要 |
PURPOSE: To obtain a phase change-type optical disk having excellent characteristics for repeated use which enables high sensitivity recording. CONSTITUTION: This medium consists of a substrate has guide grooves and at least a dielectric protective layer, phase transition type optical recording layer, dielectric protective layer and reflecting layer are formed in this order on the substrate. Recording and reproducing is performed by irradiating grooves with laser light. The guide grooves of the substrate are formed to have the width ranging from 0.15×(λ/NA) to 0.35×(λ/NA) and 40 to 80nm groove depth, wherein λ is the wavelength of the laser light for recording and NA is the numerical aperture of the lens. |
