| 摘要 |
PURPOSE:To realize high density recording, erasing and rewriting by forming two layers of thin film materials which show changes in the optical constants with irradiation of laser light on a substrate, and detecting the change in the total reflectance or transmittance due to the phase change of the reflected or transmitted light before and after the optical properties of the thin film layers change. CONSTITUTION:On a substrate 1, there formed are a first transparent layer 2 having different refractive index to the substrate 1, the first recording thin film layer 3, second transparent layer 4, second recording thin film layer 5, third transparent layer 6, and further a reflecting layer 7. Thickness of the first transparent layer 2, first recording thin film layer 3, second transparent layer 4, second recording thin film layer 5, third transparent layer 6, and reflecting layer 7 are determined so as to change the phase of transmitted or reflected light when the medium is irradiated with light after the optical properties of the medium change. Thus, the medium has high recording density although it is a phase-transition recording type and is rewritable for such a recording method using phase changes of light which enable erasing and rewriting. |
