| 摘要 |
PURPOSE:To prevent writing of error signals and increase of access time by extending both ends of tracks from the optical recording area, forming these extended areas which are out of the optical recording area by using such a material that gives reflectance in the wavelength region of laser used for writing but is not writable. CONSTITUTION:The optical card 1 which is optically writable has an optical recording area 2. Recording track lines 7 in the optical recording area 2 are extended from the area 2 to form the area 3 which is not writable. The track area of this area 3 which is not writable consists of such a material that gives reflectance in the wavelength region of laser used for writing but is not writable. The optical recording area 2 and the area 3 where writing is impossible are formed on a transparent substrate 4, on which a back substrate 6 is provided with an adhesive 5 to constitute the optical card 1. By this method, writing of error signals or deterioration of the recording material due to laser beams in nonoperating time during recording or reproducing, and moreover, increase of access time is prevented. |
