| 摘要 |
PURPOSE: A disk discriminating method is provided to make an accurate disk discriminating by using only a focus error detected from a disk reflection face by compensating an actuator gain deviation of an optical pick-up or a gain deviation of a focus servo circuit. CONSTITUTION: An actuator lowered down an objective lens for a 'td' time when a focus actuator drive voltage is applied to a downward slope Vd1(S1). The actuator raises the objective lens toward a disk for a 'tu' time when the actuator driver voltage is applied to an upward slope Vd2, and a controller sets a counter and counts for the 'tu' time(S2). The focus error signal detected for the upward time 'tu' is zero-crossed and it is discriminated whether the upward time is the same as 'tu'(S3, S4). Assuming that an intermediate value between 't1' and 't2' is 'T', if the time from the upward time point of the objective lens to the disk recording face is smaller than the reference value 'T', it is discriminated as DVD, while if the upward time point is greater than the reference value, it is discriminated as CD(S5,S6).
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