| 摘要 |
PURPOSE:To enable rewriting by about one million times without causing deterioration of the substrate on rewriting of record by forming a heat-resistant protective film between the substrate and a dielectric protective film of the optical recording medium. CONSTITUTION:On the substrate 1, a dielectric protective film 2, phase transition-type recording film 3, second dielectric protective film 4, reflecting and cooling film 6, and surface protective film 5 are successively formed in the order listed. Information is recorded, reproduced or erased by irradiating the medium with laser light entering from the substrate side to cause reversible phase transition in the phase transition type recording film 3. A heat-resistant protective film 8 is provided between the substrate 1 and the first dielectric protective film 2 of the medium. By providing the heat-resistant protective film 8 between the substrate 1 and the first dielectric protective film 2 to constitute the medium, transfer of heat of laser light to the tracking grooves in the substrate 1 is suppressed. This heat is required for the phase transition-type recording film 3 and is given by the laser light entering from the substrate side. Thus, the defectless state of the medium is maintained for about one million times of rewriting of record. |
