| 摘要 |
<p>The invention relates to a multilayer optical disc reading and/or writing apparatus comprising means for performing accurate jumps between layers of a multilayer optical disc. To perform a jump, the objective lens is moved, relative to a static reference, along a focusing direction (Z) from a first layer towards a second layer of the disc according to a set of kinetic parameters. According to the invention, a focus error signal (FE) correlated with the shift (Deltaz) between the focus point (P) and the first layer is monitored during the motion of the lens. The time period (Deltat) elapsed between a first characteristic value and a second characteristic value of said focus error signal is determined, and the set of kinetic parameters is adjusted, when said second characteristic value is reached, depending on said time period, to overcome the effects of the disc motion relative to said static reference.</p> |
