| 摘要 |
There is provided a recording/playback device able to differentiate the type of an optical disc or another such optical recording medium with a high degree of precision while correcting wavefront aberrations. The recording/playback device has a detection part for sequentially detecting the surface of a cover layer and one or a plurality of signal recording surfaces of an object to be detected on the basis of an output signal of a photodetector, a medium differentiation part for differentiating the type of the detected object on the basis of the detection results, an aberration correction element, and an aberration control part for controlling the aberration correction state of the aberration correction element. When the focal point of the light beam moves toward the signal recording surface, the aberration control part sets the aberration correction state of the aberration correction element to a state between a first aberration correction state in which the wavefront aberrations are appropriately corrected in accordance with a surface of a cover layer of a predetermined optical recording medium, and a second aberration correction state in which the wavefront aberrations are appropriately corrected in accordance with a signal recording surface of the predetermined optical recording medium.
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