Apparatus for automatically controlling focus and method thereof

Details Apparatus for automatically controlling focus and method thereof Apparatus for automatically controlling focus and method thereof

1997-09-10

2000-02-22

Tran, Thang V.

Dynamic information storage or retrieval

With servo positioning of transducer assembly over track...

Optical servo system

369 4425, 369 4432, 369 4435, G11B 709

Patent

active

060288256

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.

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