Patent ID: 8514680
Filing Date: 2013-08-20
Classification: G11B

Abstract:
1. A recording device comprising: a light irradiating and light receiving unit configured, in regard to an optical recording medium comprising a reference surface and a recording layer formed at a depth position different from the reference surface, wherein a pit row where intervals of pit formable positions in one circumference are limited to a first interval is formed in a spiral shape or a concentric shape in the reference surface, and which has a plurality of pit row phases by intervals of the pit formable positions in a pit row formation direction being set in a position which is each deviated by a predetermined second interval in the pit row which are arranged in the radial direction, to irradiate via a common object lens a first light as recording light with regard to the recording layer and a second light for obtaining reflected light from the reference surface and configured to receive reflected light of the second light from the reference surface; a tracking mechanism unit configured to change a position of the object lens in a the radial direction; a clock generating unit configured to generate a clock in accordance with the interval of the pit formable positions based at least in part on a light reception signal obtained by the light irradiating and light receiving unit receiving reflected light of the second light; a timing selection signal generating unit configured to generate a plurality of timing selection signals, which respectively represent timings of the pit formable positions in regard to the pit rows of each phase formed in the optical recording medium, based at least in part on the clock generated by the clock generating unit; a tracking error signal generating unit configured, when a pit row selected to be a target of a tracking servo out of the pit rows of each phase formed in the reference surface is a target pit row, and an intermediate position selected to be a target of a tracking servo out of the respective intermediate positions of the pit rows of each phase formed in the reference surface is a target intermediate position, to execute: generation of a first tracking error signal, which represents a positional error in the radial direction with regard to the target pit row in the irradiation spot position of the second light, by: generation of a second tracking error signal, which represents a positional error in the radial direction with regard to the target intermediate position in the irradiation spot position of the second light, by: a tracking servo control unit configured to perform tracking servo control with regard to the object lens by controlling the tracking mechanism unit based at least in part on the tracking error signal output by the tracking error signal generating unit; an offset applying unit configured to perform application of an offset using a saw-tooth wave with regard to a tracking servo loop which includes the tracking servo control unit; and a control unit configured to control output using the tracking error signal generating unit to alternately switch between the first tracking error signal and the second tracking error signal at a timing in accordance with a polarity reversion timing of the offset using the saw-tooth wave.