Patent ID: 7141319

Claim:
A substrate for a recording medium comprising: a base substrate made from a material selected from the group consisting amorphous polyolefin (APO), polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and acrylic resin; a non-recording surface-modified layer on said base substrate which is modified in surface properties by ion implantation wherein ion species comprising at least one atom selected from the group consisting of C, W, Ta, Mo, Pt, Ti, Mn, Cu and Sm from the ion implantation are implanted in the surface-modified layer; and a non-recording electrically conductive thin film metal layer made of titanium nitride on said surface-modified layer, wherein said non-recording electrically conductive thin film metal layer is formed on said surface-modified layer prior to said ion implantation so that said recording medium substrate is characterized by a hardiness against layer separation that is greater than if said ion implantation is performed prior to forming said non-recording electrically conductive thin film metal layer.