| 摘要 |
PURPOSE: To enable quantity of record used to be discriminated by visual observation by providing an area for recording the quantity of used data in which data corresponding to the quantity of an used information storing area and recorded in the recording area except an information recording area in an information recording medium in which reflectance changes when irradiated with a light. CONSTITUTION: An optical disk 1 is provided with a hub 1a, a label 1b and an information recording area 1c and is also provided with an area 1e for displaying quantity of information inside the area 1c and at an inner peripheral part between the label 1b and the area 1c. The label 1b is provided with 0, 10,...90% graduation based on 0 sector position 1d. The area 1e is constituted of plural tracks and a specific datum corresponding to the quantity of recorded information is recorded therein. Namely, record length (recording time from 0 sector) of the specific datum corresponding to the quantity of information recorded in the area 1e is used as a displaying datum 1f of the quantity of recorded information. Since the same data are recorded in plural tracks, the displaying datum 1f is visual as the change of reflectance shown by a hatching in the state of taking out the optical disk 1 from an optical disk device. |
