Abstract: A method of determining a disk type of an optical disk is provided to comprise steps of: using a first light path for forming an incident beam; moving an objective lens system corresponding to the first light path from a start position towards the optical disk; receiving a sensor output signal during the movement of the objective lens system, wherein the sensor output signal includes a central aperture signal; determining the disk type of the optical disk according to the central aperture signal.

Abstract: An optical disk drive for determining a disk type associated with a substrate thickness of an optical disk comprising a substrate is provided to comprise a source to generate a beam, an optical arrangement arranged to direct the beam to the optical disk for forming an incident beam, a sensor arranged to sense a reflected beam and to produce a sensor output signal, a focus system comprising an objective lens system and a focus controller, wherein the objective lens system is arranged to focus the incident beam into a spot, and the focus controller is arranged to generate a focus control signal to drive and position the objective lens system; and a controller arranged to cooperate with the focus controller for moving the objective lens system, to receive the central aperture signal during the movement of the objective lens system, to analyze the central aperture signal for determining the focus actuator position, and to determine the disk type associated with the substrate thickness.

Abstract: An optical disk drive for determining a disk characteristic of an optical disk comprising an information layer comprising a substantially circular track is described. The optical disk drive has an optical pickup unit arranged to generate a beam, direct the beam to the optical disk for forming an incident beam, sense a reflected beam produced by the optical disk with a sensor upon receiving the incident beam with the sensor, produce a sensor output signal from sensing the reflected beam; a disk receiving device arranged to receive the optical disk; a motor arranged to provide a transition of the disk receiving device from a first mode to a second mode in at least one transition phase; and a controller arranged to receive the sensor output signal during at least one part of the at least one transition phase and perform at least part of determining the disk characteristic from at least the sensor output signal received during the at least one part of the at least one transition phase.