| 摘要 |
PURPOSE: To impart pattern information to an optical disk by irradiating the non-information area of a read only optical disk with a pulselike laser beam and forming a hole on a reflection metallic layer. CONSTITUTION: A read only optical disk 1 is formed with a resin plate 11 like polycarbonate, reflection metallic layer 13 like Al, and a protective layer 15 like nitrocellulose. On the optical disk 1 completed with information marked in the information area 3 of the disk 1, a lot number, bar code, etc., are imparted in the following method. A pulselike YAG laser beam with a proper power level for example is emitted from the side of the protective layer 15. The irradiation area used is an annular disk area 5, 5a and a clamp area 7, which are non-information areas. As a result, the reflection metallic layer 13 is formed with a hole 17, with a necessary pattern imparted. |
