Patent ID: 7796476

Claim:
An optical disk device comprising: an optical pickup head which emits a laser beam to an optical disk and detects light reflected from the optical disk; a signal output unit configured to output at least a servo signal and an RF signal in accordance with the light detected by the optical pickup head; a determination unit configured to determine whether the optical disk is an H-to-L disk in which a light reflectance is lower in a data recorded region than in a data unrecorded region or an L-to-H disk in which the light reflectance is higher in the data recorded region than in the data unrecorded region from identification information recorded on the optical disk; a gain adjustment value memory which stores a gain adjustment value; a gain control unit which is configured to: set a first gain adjustment value Na in accordance with the H-to-L disk and the data recorded region of the gain adjustment value memory when it is determined by the determination unit that the optical disk is the H-to-L disk, arid the region to-be-read of the RF signal at the time of executing automatic servo gain adjustment is the data recorded region; set a second gain adjustment value Nb (Nb<Na) in accordance with the H-to-L disk and the data unrecorded region of the gain adjustment value memory when it is determined by the determination unit that the optical disk is the H-to-L disk, and the region to-be-read of the RF signal at the time of executing the automatic servo gain adjustment is the data unrecorded region; set a third gain adjustment value Nc in accordance with the H-to-L disk and the data recorded region of the gain adjustment value memory when it is determined by the determination unit that the optical disk is the L-to-H disk, and the region to-be-read of the RF signal at the time of executing the automatic servo gain adjustment is the data recorded region; and set a fourth gain adjustment value Nd (Nd>Nc) in accordance with the L-to-H disk and the data unrecorded region of the gain adjustment value memory when it is determined by the determination unit that the optical disk is the L-to-H disk, and the region to-be-read of the RF signal at the time of executing the automatic servo gain adjustment is the data unrecorded region; and a gain adjustment unit configured to execute automatic servo gain adjustment of the servo signal by using the first, second, third, or fourth adjusted gains set in the servo gain adjustment memory, according to the type of the optical disk and whether the region is the data recorded region or the data unrecorded region in reproducing the optical disk.