| 摘要 |
PURPOSE:To eliminate a complicated work and to mark a manufacturer's serial number, etc., of an optical disk by forming the mark by allowing a refractive index of a mark part to be different from a refractive index of other part without deforming the disk on its appearance. CONSTITUTION:As for a part in which a mark 2 of an optical disk 1 is put its, appearance is the same as that of other part of the disk, but its refractive index is different. Accordingly, when a monochromatic light is irradiated to the disk 1, an image of the mark 2 is formed on a screen 5 and the mark is discriminated. As for a forming method for the mark, a marking base 11 of a stamper 7 made of nickel is pressed by an elastic limit or below of nickel, a movement of a crystal defect occurs, a residual strain of the stamper is generated, and a mark part is formed. When the optical disk is brought to injection molding by using this stamper, the residual strain of the stamper appears as a difference of the refractive indexes on the disk, and the mark whose external appearance is not varied can be formed on the optical disk 1. |
