Patent ID: 7277373

Claim:
An optical disc apparatus comprising a motor for rotating a turn table on which an optical disc is mounted, an optical pickup for irradiating a light beam to the optical disc and receiving reflected light from the optical disc for reading and/or writing data with respect to the optical disc, and a motor controller for controlling the rotation of the motor, wherein the motor controller executes the following processes: obtaining a first widest pattern signal corresponding to a pulse width of a signal having the widest pattern among RF signals outputted from the optical pickup, when rotation speed of the optical disc reaches to a predetermined speed by driving the motor; memorizing the first widest pattern signal in a memory; supplying a braking voltage to the motor in a predetermined period; further obtaining a second widest pattern signal corresponding to a pulse width of a signal having the widest pattern among RF signals outputted from the optical pickup after supplying the braking voltage to the motor; and judging the size of the optical disc mounted on the turn table with reference to inverse numbers of the first widest pattern signal and the second widest pattern signal.