| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve such the problem that in a rewritable optical disk, there is a risk of erasing recorded data depending on energy density, since energy densities on recording planes by high frequency wave superposed by laser spot diameter formed on the recording film plane are different from one another, when a plurality of kinds of optical disks each having a different distance from the optical disk surface to a recording film plane are reproduced using a laser of the same wavelength, in high frequency wave superposition (for reduction of laser noise and light path interference) during reproduction of information in an optical disk device. <P>SOLUTION: In discrimination of an optical disk in initial adjustment after insertion of the optical disk and layer switching of a multi-layer optical disk, amplitude and the frequency of a high frequency wave superposed on reproducing laser beam are switched correspondingly to reproduced spot diameter on the recording film plane. Also, in discrimination of the optical disk and layer switching of the multi-layer optical disk, high frequency wave superposition for reproducing laser beam is stopped until finish of discrimination and completion of confirmation of pull-in to a target layer. <P>COPYRIGHT: (C)2010,JPO&INPIT |
