Apparatus for automatically controlling focus and method thereof in a disc player
US6028825A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 10, 1997 |
| Grant date | Feb 22, 2000 |
| Priority date | — |
| Expiry date | Sep 10, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0948
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for automatically controlling the focusing of a CDP (compact disc player) performs more reliable automatic control operation upon abnormal conditions of a disc such as a scratch and dust. The automatic focus controlling apparatus includes a pickup assembly for reading recorded data from a disc; an RF signal converter for converting the output signal read by the pickup assembly into an RF signal; a signal separator for separating a signal corresponding to a 3T component from the RF signal; a phase comparator for comparing the separated 3T signal with a predetermined frequency to provide a phase difference value; and a controller for controlling a focusing operation of an objective lens based on the phase difference value to provide a focus control signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.