| 摘要 |
PURPOSE:To obtain a mold having high adhering force and capable of forming long-life recording discs by roughening a non-recording area on a surface on which an irregular pattern indicating information signals is formed. CONSTITUTION:The mold for sound discs or recording discs is constituted of an area 11 on which a fine irregular pattern indicating information signals is recorded and a non-recording area 12. A part 13 of the outer periphery part and inner periphery part of the non-recording area 12 is roughened. When a plastic is molded by using such kind of a mole, the roughened area is transferred to a sound disc or a recording disc, so that the adhering force is increased at the time of adhesion or the formation of a sandwitch structure, the penetration of noxious gas or steam is prevented and highly sensitive and long-life sound discs or recording discs can be obtained. |
