Samsung Electronics Co., Ltd.

Min Hwangbo

Sung-ro Go

Byeong-Ho Park

A magnetooptical disk focus servo and tracking servo which remain stable and which make various servo control gains uniform even when the amount of light detected in a photodetecting portion changes. An operator outputs a sum signal by adding signals corresponding to an amount of light detected in at least two photodiodes among a plurality of photodiodes of the photodetecting portion. A first divider divides a focus error signal by the sum signal. A second divider divides a tracking error signal by the sum signal. A focus servo portion controls a focus actuator using the output of the first divider, and a tracking servo portion for controlling a track actuator with the output of the second divider.

Magnetooptical disk focus and tracking servo for a magnetooptical disk

A servo controlling apparatus of an optical disk drive and a control method thereof are provided for achieving precise control by automatically controlling the gain of error signals caused by the difference in the amount of light irradiated during recording and reproducing, and then using the automatically gain-controlled signal. In a first control step, a focus error signal and a tracking error signal generated from a photodetecting portion via an operator are multiplied by a predetermined value in different multipliers, and then each obtained value is divided by an RF sum signal to control the value of error to within a predetermined target value. In a second control step, each multiplied focus error signal and tracking error signal are divided by a DC signal corresponding to the average level of the RF sum signal when the error value reaches the target value.

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Anyang, South Korea

Min Hwangbo