| 摘要 |
PURPOSE:To improve water resistance and mechanical strength of a substrate by providing silica glass films on both sides of the substrate or on the surface where laser light irradiates. CONSTITUTION:On a plastic substrate 1, there are successively formed a protective film 3, recording film 4, and protective film 5. The both sides of the substrate 1 or one surface where laser light irradiates is covered with a thin film 6 comprising silica glass. This thin film 6 is formed by silica sol method or LPD method. Thereby, quality of the disk is maintained for a long period. |
