| 摘要 |
PURPOSE:To make it unnecessary to stick a label, and to prevent the contamination caused by a protrusion of a adhesive agent, by recording the level information to part other than an information recording part of an information recording medium, so that it can be discriminated visually by irradiating a light. CONSTITUTION:A disk 1 is rotated in the direction as indicated with an arrow B, a laser beam 9 which is modulated by a level signal is irradiated to a recording film of a level information recording part 2-b, also a disk 11 is moved relatively in the direction as indicated with an arrow C, and level information is recorded so as to be visible. In such a way, a process for sticking a label becomes unnecessary, and the process can be simplified. Also, since the level information is protected by a protective plate, etc., therefore, it is scarcely damaged and also it is not contaminated, therefore, its quality is improved. |
