| 摘要 |
PURPOSE:To decrease the effect of the repetitive tension by a volumetric change arising from a phase change of a recording layer by forming protective films in such a manner as to come into contact with a recording layer while pressure stresses are held applied thereon. CONSTITUTION:Grooves for tracking are formed on the surface of a polycarbonate substrate 1. A 1st protective film 2a consisting of ZnS, the recording layer 3, a 2nd protective film 2b, and a reflecting and cooling layer 4 are successively formed by a sputtering method thereon and finally, a UV curing resin 5 for protective the respective layers is formed. The values of the internal stresses of these films can be changed by changing sputtering power at the time of formation of the films 2a, 2b. The values of the internal compressive pressures are controlled by changing the sputtering conditions of the films 2a, 2b in such a manner, by which the number of the rewriting times of the optical disk is increased with an increase in the value of the initial compressive stresses. |
