Apparatus for reproducing record information of multiple-layered optical disc
US5903530A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1997 |
| Grant date | May 11, 1999 |
| Priority date | — |
| Expiry date | Nov 4, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for reproducing record information of a multiple-layered optical disc is provided with: an optical pickup having a light source for emitting a reading light, an objective lens for condensing the emitted reading light onto one of the information record layers, a focus actuator for moving the objective lens in a focus direction, and a light-detection device for detecting the reflected reading light and outputting a light detection signal; a focus error generation device for generating a focus error signal; an acceleration/deceleration signal generator for generating and outputting to the focus actuator an acceleration signal to accelerate the objective lens in the focus direction and a deceleration signal to decelerate the objective lens in the focus direction; an inter-layer distance measurement device for measuring an interlayer distance between the information record layers of the multiple-layered optical disc; and a controller for measuring a time duration since the acceleration signal is generated until the focus error signal reaches a predetermined threshold level, and for controlling the acceleration/deceleration signal generator to set a magnitude of the decelera…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.