Patent ID: 6676791
Filing Date: 2004-01-13
Classification: G11B,Y10T

Abstract:
A process for the manufacture of an optical information-recording medium that has at least two or more information-recording surfaces in the thickness direction of a substrate composed of a resin material that allows reading of the information recorded on each information-recording surface of the two or more information-recording surfaces by varying the focal position of a playback laser beam incident thereon comprising:a first step for forming a first information-recording surface on said substrate by using a first stamper having a crenulated pattern formed thereon corresponding to pits or guide grooves; a second step for forming a first light reflecting material on said substrate; a third step for mounting said substrate formed with said first light reflecting material on a first mold: a fourth step for mounting a second stamper having a crenulated pattern formed thereon corresponding to pits or guide grooves on a second mold; a fifth step for positioning a thermoplastic resin sheet having uniform thickness between said substrate formed with said first light reflecting material and said second stamper; a sixth step for adhering said thermoplastic resin sheet on said substrate in conjunction with transferring the crenulated pattern formed on said second stamper to the surface of said thermoplastic resin sheet by closing said first and second molds in order to add pressure to said thermoplastic resin sheet sandwiched between said substrate and said second stamper, wherein at least one of said substrate formed with said light reflecting material and said second stamper and said thermoplastic resin sheet is heated; a seventh step of forming a second information-recording surface on a surface of said thermoplastic resin sheet other than the surface adhered to said first light reflecting material by solidifying said thermoplastic resin sheet through a cooling down process when said first and second molds are closed and with said thermoplastic resin sheet in a sandwiched position between said substrate and said second stamper; and an eighth step of peeling said second stamper from said thermoplastic resin sheet.