Patent ID: 7294281
Filing Date: 2007-11-13
Classification: G11B

Abstract:
1. A manufacturing method of an original disc optical information recording medium for transferring and producing a substrate for an optical information recording medium including both a land and a groove as a recording track, comprising: producing shapes of the land and the groove on an original disc material surface; performing a plasma etching process on the original disc material surface, on which the shapes of the land and the groove are formed, setting an inclination angle of the original disc surface corresponding to said groove side to 25° or more and 40° or less during the manufacturing of the original disc surface to produce the shapes of the land and groove, and setting both of arithmetic average roughness (Ra) on the original disc surface corresponding to said land surface and said groove surface to 0.2 to 0.7 nm, during the manufacturing of the original disc surface to perform the plasma etching on which the surface roughness (RA) is formed, wherein a difference between the arithmetic average roughness (Ra) on the original disc surfaces corresponding to said land surface and said groove surface is 0.2 nm or less.