| 摘要 |
An optical disc drive for reading or writing information on a multilayer optical disc having a plurality of recording layers by irradiating the disc with a light beam includes an optical pickup for irradiating the disc with the light beam, a focus error signal generator for generating a focus error signal that indicates a state of displacement of a focal point of the light beam from a recording layer based on reflection from the disc, a recording state detector for detecting a data recording state at a landing point of the focal point in a focus jump, a threshold setting unit for setting a threshold to be compared with the focus error signal based on the data recording state at the landing point, and a focus jump controller for controlling the focus jump based on a result of comparison of the focus error signal with the threshold.
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