| 摘要 |
PURPOSE:To obtain a recording film of high accuracy such as a magnetic film on a cylindrical substrate even if the surface of the substrate is not finished to high accuracy, by bringing a plastic tube shrinkable by heating into contact with the outside of the substrate and by forming a signal recording film such as a magnetic film on the surface of the tube. CONSTITUTION:A plastic tube 3 of polyethylene terephthalate or the like shrinkable by heating is brought into contact with a cylindrical substrate 1 of metal or synthetic resin to obtain a surface having about 0.1 S surface roughness even if the surface of the substrate is not finished to high accuracy. When the obtd. surface is not sufficiently smooth, it can be simply finished to about 0.1 S surface roughness by buffing or other methods. A magnetic film 4 or a recording film 4 for optical recording and reproduction is then formed on the surface. The resulting cylindrical recording medium is put in a holding case 13 in a freely rotatable state so as to protect the film 4, and a recording and reproducing element is set in a slit 14 cut in the case 3 to enable high-density recording and reproduction. |
