Optical disk device which performs auto gain control process on servo signals which perform illuminating control of a light beam on the disk's recording surface

An optical disk device comprising:

• a recording signal output unit to output a signal to be recorded on an optical disk;
• an illuminating device to illuminate a recording surface of the optical disk with a light beam;
• a light generation control unit to control the intensity of the light beam according to the signal to be recorded;
• a calculating unit to calculate and output a value according to the level of the signal to be recorded;
• a light detector to receive the reflected light from the optical disk and to convert the reflected light to an electrical signal;
• a gain adjustment unit to adjust the level of the output signal from the light detector, based on the gain according to the output value from the calculating unit;
• and
• a control unit to control the illuminating device according to the output signal from the gain adjustment unit,
• wherein the gain adjustment unit includes an A/D converter to convert the output signal from the light detector and the output signal from the gain adjustment unit into digital signals, and performs digital calculations using the digital signals which are output from the A/D converter.

An optical disk device, comprising:

• an illuminating device to illuminate a recording surface of an optical disk with a light beam;
• a light generation control unit to control intensity of the light beam according to a signal to be recorded;
• a calculating unit to calculate a value according to a level of the signal to be recorded;
• a gain adjustment unit to adjust the level of the light beam output by the illuminating device, based on the gain according to the output value from the calculating unit;
• an auto gain control unit to find a gain based on a level found by the calculating unit and based on an output from said gain adjustment unit;
• and
• a control unit to control the illuminating device according to the output signal from the gain adjustment unit.

An optical disk device comprising:

• an input unit to illuminate a recording surface of the optical disk with a light beam carrying an input signal;
• a calculating unit to calculate and output a value according to the level of the signal to be recorded;
• a light detector to receive the reflected light from the optical disk and to convert the reflected light to an electrical signal;
• a gain adjustment unit to adjust the level of the output signal from the light detector, based on the gain according to the output value from the calculating unit;
• an auto gain control unit to find a gain based on the value found by the calculating circuit and based on an output signal from said gain adjustment unit;
• and
• a control unit to control the illuminating device according to the output signal from the gain adjustment unit and the gain from the auto gain control unit.

A method for controlling an optical disk device comprising:

• illuminating a recording surface of the optical disk with a light beam;
• controlling the intensity of the light beam according to a signal to be recorded;
• calculating and outputting a value according to a level of the signal to be recorded;
• detecting a reflected light from the optical disk and converting the reflected light to an output signal;
• adjusting the level of the output signal, based on a gain according to the output value from said calculating;
• finding a second gain based on a level found from said calculating and based on an output from said adjusting;
• and
• controlling the illuminating device according to an output signal from said finding.