| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk for copying prevention by providing a signal recording surface having signals recorded by a pit string in one surface, forming a metallic layer contacted with the signal recording surface for covering the same and setting the thickness of this metallic layer to be larger than the depth of a pit depth. SOLUTION: A signal recording surface 2 having a signal recorded by a pit 5 is formed on one surface of a light-transmissive substrate 1, and a metallic layer 4 and a protective layer 4 which are made of Al are sequentially formed to be in contact with the signal recording surface 2. When the thickness of the metallic layer 3 is set nearly equal to the depth of the pit 5, the surface 6 of the metallic layer 3 opposite the side contacted with the pit 5 is very small compared with the pit 5 even if rectangular recessed and projecting parts are formed, and thus no recessed and projecting parts are formed over the full region of a recording medium. Therefore, even if the protective film 4 is eliminated to make a stamper for a copy disk, the information of the pit 5 formed on one surface of the light-transmissive substrate 1 is not reflected thereby preventing copying. |
