Patent ID: 7391692

Claim:
A disk apparatus adapted to record and read data on and from a recordable optical disk, and to read data from a read-only optical disk, the disk apparatus comprising: a spindle motor adapted to rotate an optical disk; a light emitter configured to emit a light beam to be reflected on the optical disk; a lens through which the light beam is focused on the optical disk; a light detector configured to detect a reflected light beam that is reflected from the optical disk, the light detector being further configured to output a detection signal based on an amount of the reflected light beam detected; and a controller operatively coupled to the light detector and the lens, and configured to determine whether the optical disk is a recordable optical disk based on the detection signal outputted from the light detector, the controller being further configured to adjust the lens to shift a spot on the light detector at which the reflected light beam is incident by shifting a focus point of the light beam on the optical disk in a radial direction of the optical disk at least the first time the controller determines that the optical disk is not a recordable optical disk, the light detector having first and second portions, which respectively output first and second detection signals, and the controller being configured to determine that the optical disk is a recordable disk if a differential signal indicating a difference between first and second detection signals of the first and second portions has a frequency within a frequency range of a wobble signal.