Process and apparatus for producing a substrate sheet for an information recording medium, and an information recording medium using the same

摘要

A process for producing a substrate sheet for an information recording medium having a preformat on the surface of the substrate sheet comprises the steps of: providing a roll stamper (2) having a pattern corresponding to the preformat on the surface of the roll stamper; providing a roll (1) disposed opposingly to the roll stamper; providing a means for defining a gap between the roll stamper and the roll; melt-extruding a resin to form a molten substrate sheet (4) having a predetermined width; and introducing the molten resin sheet into the gap to transfer the preformat pattern to the molten resin sheet, wherein a pair of grooves are provided around the surface of the roll stamper and/or the roll, the molten resin sheet is introduced so that the edges of the molten resin sheet are introduced between each of the grooves and the surface of the roll or roll stamper which is disposed opposite to the roll or roll stamper of which the grooves are provided. An apparatus for producing the substrate sheet comprises the roll stamper, the roll and the means for defining a gap between the roll stamper and the roll, and means (5,6) for the extruding step. An information recording medium comprises a substrate and a recording layer on the substrate, wherein the substrate is formed by the process.