| 摘要 |
A focus offset correction method for optical information read/write device, the device comprising: a first amplitude detection circuit for detecting amplitude of a tracking error signal obtained from a record medium; a second amplitude detection circuit for detecting amplitude of an information reading signal; a tracking servo circuit for moving a laser beam to follow fluctuation of a track on the record medium; a focus servo circuit for controlling the laser beam so that a beam waist thereof is positioned on the record medium; and an offset adder for applying an offset to the focus servo circuit. The focus offset correction method comprises a first process for determining a range of the offset in which range an output from the first amplitude detection circuit always exceeds a predetermined value; and a second process for determining the offset which makes an output from the second amplitude detection circuit almost maximum.
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