Optical information reproduction device, optical information recording device, optical information reproduction method, and optical information recording method

Abstract

The present invention accurately operates a tilt servo even if a gap servo is operated with a small gap. A condensing unit () generates a near-field light and condenses a laser beam on an optical disk (), a light quantity detection unit () detects light quantity of return light from an area where the near-field light is generated, a gap control unit () controls a gap between the condensing unit () and the optical disk () based on the light quantity of the return light, a tilt calculation unit () calculates, in a state of controlling the gap, an inclination amount between the condensing unit () and the optical disk () based on the light quantity of the return light, a tilt error signal generation unit () generates from the inclination amount a tilt error signal, which is a signal from which a fluctuation component of the return light generated due to decentering of the optical disk () is removed, and a tilt control unit () controls the inclination between the condensing unit () and the optical disk () based on the tilt error signal.