Apparatus for controlling bias amount of focus error signal
US5751674A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1996 |
| Grant date | May 12, 1998 |
| Priority date | — |
| Expiry date | Dec 23, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0941
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical information reproducing and/or recording system is provided with an optical system for irradiating a light beam to an information record surface of an information record medium and detecting the light beam reflected from the information record surface to output a light detection signal, an amplifying device for amplifying the light detection signal and generating a focus error signal which indicates an error of a focus point of the light beam with respect to the information record surface, and a feed back device for feeding back the focus error signal in the focus servo loop to change the focus point in accordance with a level of the focus error signal. An apparatus for controlling a bias amount of the focus error signal is provided with: a superimposing device for superimposing a disturbance signal to flutter the focus point with respect to the information record surface, onto the focus error signal; an error amount detecting device for detecting a focus error amount of the focus point, on the basis of the light detection signal outputted when the disturbance signal is superimposed; a parameter calculating device for calculating a gain parameter corresponding to an ampl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.