| 摘要 |
PROBLEM TO BE SOLVED: To record rewrite needless control data on a ROM surface and to record rewrite needed data on a RAM surface based on the control data by providing both the ROM surface and the RAM surface on a sheet of a disk. SOLUTION: A ROM surface embossing an aluminum layer on a transparent substrate and having data beforehand recorded is stuck to a postscript type or rewrite type RAM surface capable of recording and erasing the data by causing a recording layer an optical change accompanying an atomic arrangement by light beam irradiation. That is, an optical disk 1 is a disk sticking a large capacity data recording medium DVD-ROM and a DVD-RAM on its both sides. Thus, on the lower surface side ROM surface of the optical disk 1, information is reduced by irradiating laser light with a lower side optical head 4 and detecting pit length from reflected light change of pits with different lengths embossed on the recording surface and on the upper surface side RAM surface information is recorded/erased by irradiating the laser light and a thermal phase change on the recording layer and is reproduced by detecting an optical characteristic change from reflected light. |
