| 摘要 |
PURPOSE:To obtain a disk which has reduced variation with time such as warp, distortion, etc. and has high strength under high temperature and high humidity, by having a symmetrical structure for the hydroscopic state, physical characteristics, etc. of two disk resin substrates. CONSTITUTION:An additional layer 6 of photosetting resin is provided to the 1st disk substrate 5 made of a synthetic resin. Furthermore, an optical recording layer 7 is vapor-deposited on the substrate 5. Then an additional layer 6a of photosetting resin is provided to the 2nd substrate 5a of the same material as the substrate 5. Both substrates 5 and 5a are joined together by means of a photosetting adhesive 8. The substrates 5 and 5a are preserved for a long period of time under a constant temperature and a constant humidity to obtain an equal hydroscopic state between both substrates. Then both substrates are joined together when each of these substrate is set under a balanced state with respect to the humidity. |
