Patent ID: 6168207
Filing Date: 2001-01-02
Classification: G11B,Y10S

Abstract:
An optical disc having a watermark formed by a source of irradiation, said disc comprising: a first transparent substrate having an information signal recording surface; a reflective layer formed on the information signal recording surface of said first transparent substrate; an adhesive layer formed on said reflective layer; a dummy transparent substrate formed on said first transparent substrate sandwiching said reflective layer and said adhesive layer; and a mask pattern arranged between the source of irradiation and said first transparent substrate, wherein the mask pattern has a specific shape for partially shielding said first transparent substrate from the source of irradiation, and wherein a position of said reflective layer is microscopically and partially displaced corresponding to said specific shape of said mask pattern from an original position of the reflective layer and the thus displacement of the reflective layer visually exhibits said watermark having said specific shape after said mask pattern has been irradiated by said irradiation source.