| 摘要 |
According to one embodiment, a focus position control method includes irradiating a beam to an optical disc via an objective lens, receiving reflected light and outputting a signal, generating a focus error signal, detecting an amplitude of a signal high-pass-filtering the signal, detecting an intensity of a signal low-pass-filtering the signal, supplying a driving voltage corresponding to the focus error signal to a drive coil configured to move the objective lens to an optical axis direction of the beam when the amplitude is larger than the first value, or when the amplitude is not larger than the first value and the intensity is smaller than the second value, and supplying a driving voltage having a constant voltage value to the drive coil when the amplitude is not larger than the first value and the intensity is not smaller than the second value.
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