| 摘要 |
PURPOSE:To improve reliability by using a light metal as a substrate material and forming a rewritable recording layer on the substrate then coating the entire surface of the substrate with a transparent plastic material by cast polymn. CONSTITUTION:A transparent protective layer consisting of a plastic material is provided by enclosing the front and rear thereof by a cast polymn. method. The substrate 6 provided with the recording media 5 on the front and rear is positioned in a vessel for polymn. and a prepolymer of polymethyl methacrylate is poured therein by which the polymer is cast and molded. The molding formed in such a manner is subjected to the sizing of the inside diameter and outside diameter by a lathe, etc. by which the optical disk coated with the resin layer 7 to a specified thickness is obtd. The resin such as epoxy resin which is transparent to and less absorbent of the wavelength of the laser to be used and is highly resistant to moisture is also used as the resin to be used. The moisture resistance and oxidation resistance are thus made thorough and the reliability of the optical disk memory is improved. |
