OPTICAL INFORMATION REPRODUCTION DEVICE, OPTICAL INFORMATION RECORDING DEVICE, OPTICAL INFORMATION REPRODUCTION METHOD, AND OPTICAL INFORMATION RECORDING METHOD

摘要

In order to accurately operate tilt servo even when gap servo is operated with the gap being set small, a light focusing unit (102) generates near-field light and focuses laser light onto an optical disk (1), a light amount detection unit (104) detects the light amount of feedback light from a region in which the near-field light is generated, a gap control unit (105) controls the gap between the light focusing unit (102) and the optical disk (1) on the basis of the light amount of the feedback light, a tilt calculation unit (106) calculates the amount of tilt between the light focusing unit (102) and the optical disk (1) on the basis of the light amount of the feedback light while the gap is being controlled, a tilt error signal generation unit (107) generates a tilt error signal that is a signal obtained by removing a fluctuation component of the feedback light due to the decentering of the optical disk (1) from the amount of tilt, and a tilt control unit (108) controls the tilt between the light focusing unit (102) and the optical disk (1) on the basis of the tilt error signal.