| 摘要 |
PURPOSE:To prevent a bimetal phenomenon and to evade curvature by providing a waterproof layer on a read side. CONSTITUTION:On a substrate 1 of acrylic resin, etc., a reflecting film 2 made of metal such as aluminum and a protecting film 3 made of acrylic lacquer, etc., are laminated. On the surface of this substrate, the waterproof film 4 whose moisture permeability is <=5g/m<2>.24hrs, preferably, <=1g/m<2>.24hrs expressed in terms of 0.1mm. thickness at 40 deg.C on the basis of JIS(Japanese Industrial Standard)-Z208 is formed. This optical disk includes not only a one-sided disk, but also a disk to which the protecting film is stuck together with an adhesive. This optical disk has less deformation even after being left in a thermohygrostat. |
