公开(公告)号：EP0858070A4

公开(公告)日：2004-04-14

申请号：EP97935862

申请日：1997-08-22

申请人： SONY CORP ,  NIPPON ZEON CO

发明人： OYANAGI EIKI ,  SASA TAKESHI ,  IMAI YASUYUKI ,  TAKINO HIROSHI ,  KOHARA TEIJI ,  OSHIMA MASAYOSHI

IPC分类号： B29C70/64 ,  C08F32/04 ,  G11B5/596 ,  G11B5/60 ,  G11B5/73 ,  G11B5/82 ,  G11B5/84 ,  G11B21/21 ,  G11B23/00 ,  G11B5/64

CPC分类号： G11B23/0021 ,  B29C70/64 ,  C08F32/04 ,  G11B5/59633 ,  G11B5/6011 ,  G11B5/7315 ,  G11B5/82 ,  G11B5/8404 ,  G11B21/21 ,  Y10S428/913 ,  Y10T428/21

摘要： A disc medium substrate which is made of resin and used for a disc, for instance a magnetic disc, on/from which information is recorded/reproduced with a floating head. Protrusions higher than 50 nm are not formed on the surface of the substrate which is scanned by the floating head. The substrate is so molded that the number of particles in the molding material whose particle diameters are larger than 5 mu m is not more than 10000/g. The molding can be injection molding. Thermoplastic norvolnene system resin can be employed as the molding material. Projections and recesses corresponding to recording tracks may be provided on the substrate.