| 摘要 |
PROBLEM TO BE SOLVED: To decrease reading errors and to improve vibration resistance by specifying the variation in the thickness of the substrate of an information recording medium constituted by laminating a dye recording layer, reflection layer consisting of a metal and a protective layer consisting of a resin in this order on the substrate and the offcentering of the substrate. SOLUTION: The variation in the thickness of a stamper at the time of forming the substrate by an injection molding machine is confined to <=20 μm, by which the substrate having the variation in the thickness within 30 μm is obtd. The variation in the thickness of the stamper mainly occurs in the variation at the time of a plating treatment and, therefore, the variation in the thickness of the stamper is confined to <=20 μm by sufficiently circulating the plating liquid in a bath at the time of the plating treatment or rotating the stamper. The substrate having the eccentricity of <=60 μm is obtd. by confining the eccentricity of the stamper to <=50 μm. Since the offcentering of the stamper occurs in the positional accuracy at the time of forming a center hole, the offcentering of the stamper is confined to <=50 μm by enhancing the positional accuracy. |
