| 摘要 |
PROBLEM TO BE SOLVED: To provide a bonding type optical disk which is substantially free of the deterioration in the changes in the properties of a substrate, recording layer and reflection layer and the deterioration in the adhesiveness and mechanical strength of the disk in spite of long-term use or the use under the environment of a high temp. and high humidity. SOLUTION: This optical disk is constituted by forming the recording layer or the reflection layer on the great part of the surface of at least one substrate of two sheets of light transparent substrates 2A, 2B and bonding these substrates to each other via an adhesive layer in such a manner that the recording layer and the reflection layer exist on the inner side. The solvent extraction rate of the adhesive layer is set at <=8%, by which the amt. of the unreacted matter remaining in the adhesive layer of the optical disk is drastically decreased and the optical disk having the high reliability is provided. |
