| 摘要 |
PURPOSE:To easily obtain an optical disk provided with a guide groove, by forming a thermoplastic substance layer on the lower surface of a metallic layer of an optical disk, so that the guide groove having prescribed depth can be formed easily by irradiation of a laser beam. CONSTITUTION:On a transparent substrate 12 such as glass or acrylic resin, of an optical disk 12, a transparent thermoplastic resin layer 14 such as acrylic resin, and a low melting point metallic layer 15 such as Te and Bi are provided. The optical disk 12 is rotated by a spindle 12, and a light beam from a laser 16 is irradiated through a lens 17, a galvano-mirror 19 and a lens 18. Intensity of a laser beam is controlled so that a groove 21 having depth of 1/8 wavelength is formed on the thermoplastic resin layer 14, without evaporating the metallic layer 15. In case information is recorded, a bit 23 is formed by irradiating the guide groove 21 with a recording laser beam 22. In this way, the optical disk 12 provided with the guide groove 21 is obtained easily. |
