| 摘要 |
A tracking servo device for use with an optical disc apparatus includes a photodetector unit having a plurality of photodetectors (PD1,PD2) each of which is split in association with the direction of tracks formed on an optical disc, and a tracking error generating unit for finding the difference in outputs from at least two of the photodetectors of the photodetector unit for generating a tracking error signal (TE). The tracking servo device includes a first correction unit (100) for removing an offset produced in the tracking error signal when the tracking servo is on, and a second correction unit (200) for removing an offset produced in the tracking error signal when the tracking servo is off. The tracking servo device also includes a switching unit (300) for selecting the first correction unit (100) or the second correction unit (200) when the tracking servo is on or off, respectively, for producing a tracking error signal freed of the offset component extracted by the second correction unit (200). The tracking servo device further includes a control unit for controlling the holding time of the offset component in the offset holding unit. <IMAGE> |
