| 摘要 |
PURPOSE: To obtain an optical disk on which land and groove recordings are possible by recording the preformat signal to land parts while making the signal phsical recesses and recording the preformat signal to groove parts while changing the physical properties of the irradiated parts in groove parts by an irradiating with a laser beam. CONSTITUTION: The preformat signal to land parts 11 is recorded while making the signal same physical recesses 14 as conventional one and the preformat signal in groove parts 12 is recorded while changing the physical properties of the irradiated parts 15 by the irradiating with the laser beam so as to have compatibility with a conventional optical disk in which only land parts are made to be a recording and reproducing area. In reproducings of preformat signals, the preformat signal of land parts 11 is reproduced by the change of the reflected light quantity of a laser beam and the preformat signal of the groove parts 12 is reproduced by the change of the polarization direction of the reflected light of the laser beam. |
