Abstract: An optical disc drive scans selected tracks on a record carrier via a beam of radiation (24) from a head (22). The head is positioned on the track by a tracking system. The tracking system includes a main servo loop, constituted by a motor (40) for moving the head along a rail (46) transverse to the tracks, position means (41) for generating a position signal in dependence of an actual position of the head, and an amplifier (44) generating a driving signal coupled to the motor. The amplifier has an adjustable gain that is set in dependence on a friction profile. The device has a memory (34) for storing the friction profile as determined during a calibration process. By compensating friction of the rail a reliable response of the tracking system to jump commands is achieved. Power dissipation is reduced because the driving signal as generated is just strong enough to move the head along the rail.

Abstract: A record carrier has pattern of substantially parallel tracks constituting a data area, and a first and second boundary mark on predefined transverse positions bordering the data area. An optical disc drive scans the record carrier via a beam of radiation (24) from a head (22). The device has a control unit for determining a position of a selected track, and a tracking system for positioning the head on the selected track via a jump by a motor (40) that moves the head transverse to the tracks. The device has a head range unit (32) for detecting the boundary marks via the beam and controlling the motor for limiting said transverse movement of the head to a head range corresponding to the data area bordered by the boundary marks. Hence the motor is stopped (48) to prevent the head from exceeding head range corresponding to the data area without position sensors or mechanical elements.

Abstract: An optical disc drive scans tracks on a record carrier via a beam of radiation (24) from a head (22). The head is positioned on a selected track by a tracking system. A motor (40) moves the head transverse to the tracks in dependence on a position signal, which is generated in dependence on a number of revolutions of the motor A control unit (20) determines a distance of moving the head based on the position of the selected track and a current position of the head. An accurate track pitch ratio is retrieved from the record carrier to calculate the distance to be moved. A memory (34) stores a motor transfer rate as determined during a calibration process, which motor transfer rate indicates a number of revolutions of the motor for a predefined moving distance. The motor transfer rate enables translating the positions as determined and a distance to move the head into in revolutions of the motor.

Abstract: The invention relates to a pickup unit (1) for reading and/or writing data on a disk (2). The pickup unit comprises a base (5), a lens (3) in a lens holder (4) which is suspended from the base (5) and which is movable in at least a focusing direction of the lens (3), a pullback arrangement (9), and/or a locking arrangement (12, 12?). The pullback arrangement (9) and the locking arrangement (12, 12?) are adapted to act on the lens holder in order to prevent collisions between the lens (holder) and the disk, the pullback arrangement (9) is adapted to pull the lens holder (4) into an inoperative position remote from the disk, while the locking arrangement (12, 12?) is adapted to subsequently lock the lens holder in the inoperative position. In this manner collisions due to strong external mechanical forces or pulses exerted on the pick up unit can be effectively prevented.

Abstract: The invention relates to a system for reading data stored on an information carrier (201), said system comprising: an optical element (202) for generating an array of light spots (203) from an input light beam (204), said array of light spots (203) being intended to scan said information carrier (201), a detector (205) for detecting said data from an array of output light beams generated by said information carrier (201) in response of said array of light spots (203).

Abstract: Device for reading of and/or writing on a disc. The device is provided with at least one shaft (2, 3) and a carrier (10) movable along said shaft. The carrier is provided with at least one actuator (14) which is electrically connected to a control device (16). The actuator is electrically connected to said control device by means of said shaft.