Apparatus for automatically adjusting focus offset and method thereof in a disc player
US6252835A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 5, 1999 |
| Grant date | Jun 26, 2001 |
| Priority date | — |
| Expiry date | Aug 5, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/094
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for automatically controlling the focusing of a compact disc player (CDP) 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; and 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.