| 摘要 |
An optical disc apparatus includes an amplitude obtaining portion receiving S shaped waveform information of focus error signal from a focus error signal processing portion to obtain amplitude of the S shaped waveform and a discriminating portion discriminating kind of objective lens disposed in a light path of an optical pickup device. The discriminating portion changes controlled variable of a spherical aberration compensating element into a plurality of prescribed control values, and obtains the amplitude of S shaped waveform from an amplitude obtaining portion for each of the control values. Then the discriminating portion performs discrimination of kind of the objective lens disposed in the light path based on that a rate of change of the amplitude of S shaped waveform to change of controlled variable of the spherical aberration compensating element is different in response to kind of the objective lens.
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