Digital disk player

A digital disk player for reproducing a record formed on a disk, the digital disk player comprising:

• an optical pickup having an objective lens and a focus actuator for moving the position of the objective lens such that a focal point of the objective lens is adjusted relative to the disk;
• an error signal generation section for generating a focus error signal which is proportional to a signal output from said optical pickup;
• a focus search signal generation section for generating a focus search signal;
• an error signal level detection section for detecting a peak level of the focus error signal when the objective lens passes an in-focus position relative to a signal recording layer of the disk in response to the focus search signal during focus search control;
• a comparison section for comparing the peak level of the focus error signal output from said error signal generation section with a preset level during focus search control, and for outputting a signal when the level of the focus error signal is higher than the preset level;
• a counter for counting the number of signals output from said comparison section;
• and
• a system controller for identifying the disk as a single layer disk or a dual layer disk on the basis of a count value transmitted from said counter, and for executing focus servo control and servo gain control in response to the identification of the disk.

A digital disk player for reproducing a record formed on a disk, the digital disk player comprising:

• an optical pickup having an objective lens and a focus actuator for moving the position of the objective lens such that a focal point of the objective lens is adjusted relative to the disk;
• an error signal generation section for generating a focus error signal which is proportional to a signal output from said optical pickup;
• a focus search signal generation section for generating a focus search signal;
• an error signal level detection section for detecting a peak level of the focus error signal when the objective lens passes an in-focus position relative to a signal recording layer of the disk in response to the focus search signal during focus search control;
• a single/dual discrimination section for identifying the disk as either a single layer disk or a dual layer disk on the basis of a peak value of the focus error signal;
• and
• a system controller for executing focus servo control and servo gain control with respect to the disk on the basis of a disk identification result generated by said single/dual discrimination section.

A servo gain control method for a digital disk player which reads and reproduces recording data from a dual layer disk having first and second signal recording layers, said method comprising the steps of:

• determining a servo gain coefficient for reproduction from each of the first and second signal recording layers on the basis of a signal amplitude read from the signal recording layer after the dual layer disk is loaded in the digital disk player;
• storing the determined servo gain coefficient for each of the first and second signal recording layers in a memory;
• and
• controlling a servo gain at the time of reproduction using the stored servo gain coefficient corresponding to a selected one of the first and second signal recording layers from which recording data is to be reproduced.

A digital disk player for reproducing a record formed on a dual layer disk having first and second signal recording layers, said digital disk player comprising:

• an optical pickup having an objective lens and a focus actuator for moving the position of the objective lens such that a focal point of the objective lens is adjusted relative to the disk;
• an error signal generation section for generating a focus error signal which is proportional to a signal output from said optical pickup;
• a focus search signal generation section for generating a focus search signal;
• an error signal level detection section for detecting a level of the focus error signal when the objective lens passes an in-focus position relative to a signal recording layer of the disk in response to the focus search signal during focus search control;
• an actuator driver for controlling a distance between the objective lens and a recording surface of the dual layer disk by driving the focus actuator in response to a selected one of the focus search signal and the focus error signal;
• a system controller for determining a servo gain coefficient with respect to each of the first and second recording layers on the basis of the level of the focus error signal detected by said error signal level detection section;
• and
• a gain control section for controlling a servo gain on the basis of the servo gain coefficient determined by said system controller.