| 摘要 |
PROBLEM TO BE SOLVED: To make a recorder and/or a reproducer capable with plural kinds of optical disks with the same system by bringing only reflectance of a medium identification area of plural different kinds of optical disks mutually does to make kinds of the optical disks discriminatable with a laser beam having prescribed same intensity and to perform a recording and reproduction in accordance with the kind of the optical disk. SOLUTION: The reflectance of the medium identification area 12 of an optical disk 1 having weaker reflectance is set higher than that of the signal recording area 11 of the disk 1 by changing optical constants while heating a recording film by irradiating the area 12 with a laser beam having prescribed intensity to perform the reading of information inherent to the disk 1 with the weak laser beam. Thus, the disk information are read out with the same weak laser beam as that in an optical disk having higher reflectance without writing unwanted information in the medium identification area 12 and after respective parameters of the intensity of a laser beam or the like are set to values in accordance with the optical disk whilst an optical head scans a transition are 13, the recording or reproducing of the signal recording area 11 is performed. Moreover, reflectance of both areas 11, 12 can be made to be different by making constitution of the films in the areas differ with each other. |
