| 摘要 |
PURPOSE:To maintain information for a long period by detaching an outer periphery pressure ring after information is written and separating two optical disks, and fixing them together by using the outer periphery pressure ring after forming a moisture-resisting protective film on a recording layer. CONSTITUTION:The recording layer 5 provided on an optical disk substrate is coated with silicon oxide, silicon nitride, etc., to hundreds of Angstrom to form the moisture-resisting protective film 7, so that oxidation is prevented. Thus, an upper optical disk 8 and a lower optical disk substrate 9 are constituted separably, joined together across an 0 ring 10, and compressed fixedly by using the outer periphery pressure ring 11. The ring 11 is made of synthetic resin and clamped with a screw 12. Thus, the substrates 8 and 9 are easily separated from each other and jointed together, and information is maintained for a long period because of the protective film 7. |
