Focusing controller for focus jump control between recording layers of multilayer disk
US6777657B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 2002 |
| Grant date | Aug 17, 2004 |
| Priority date | — |
| Expiry date | Apr 3, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A focusing controller executes an appropriate focus jump even in a multilayer disk having layers of characteristics greatly different from each other. The focusing controller has an optical pickup including an objective lens for converging the light beam and a detector for receiving reflected light from the multilayer recording medium; an error signal generator for generating a focus error signal of the irradiated light beam from a detecting signal of the detector; an actuator for operating the objective lens; and a controller for controlling a focusing position of the light beam by operating the actuator based on the focus error signal. The controller calculates intensities of the reflected lights of two layers based on the detecting signal of the detector, and thus controls the timings of acceleration and deceleration signals of a focus jump between these two layers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.