Abstract: An apparatus having a frame (1) carrying a turntable (3) for supporting the information carrier, which turntable is rotatable about an axis of rotation (3A), a slide (9), which is movable between two end positions, with a scanning unit, guide spindles (5, 7) and a linear motor unit (17, 19) for the slide, and an electrically energizable clamping unit (21). In the non-energized condition the clamping unit clamps the slide in any arbitrary stationary position of the slide along its path and in the energized condition it does not clamp the slide. During operation of the device a control unit at least substantially simultaneously turns on a first energizing current to the motor drive unit and a second energizing current to the clamping unit at the beginning of a displacement of the slide and at least substantially simultaneously turns off the first energizing current and the second energizing current at the end of the displacement.

Abstract: An electromagnetic drive unit comprises a stator (2) and an armature (4) which is pivotable about a pivotal axis (5) and which cooperates with the stator via an air gap. In order to minimize the volume and to obtain a maximum efficiency, the armature is arranged coaxially around the stator, the stator comprising at least two polepieces (6A) which are interconnected by a stator member (6B) carrying a coil (8). The armature comprises a plurality of radially magnetized poles (28A, 28B) which correspond in number to at least the number of polepieces, which poles are tangentially juxtaposed with alternately opposite polarities.

Abstract: An optical scanning unit for scanning recording tracks of a record carrier with a radiation beam. The beam is emitted by a radiation source arranged at one end of a tubular member and is concentrated to a radiation spot by a lens system arranged at the other end of the tubular member. A double prism disposed between the source and lens system splits-off a reflected secondary radiation beam and directs it laterally towards an electronic output device through a lateral aperture in the tubular member. The output device converts the modulated reflected radiation into an electrical signal. The radiation source and the double prism are radially and axially aligned within the required tolerances on a metal prism support which, within an adjustment range, can be moved axially relative to the tubular member and which can be rotated to a limited extent.

Abstract: A swing-arm device (5) for an optical disk player comprises a swing arm (16), which near one end (17) carries an optical scanning unit (6) and which is electromagnetically pivoted by means of coils (27, 28) and a permanent magnetic stator (29, 30, 49-52, 54) arranged on the swing arm. The center of mass (Z) of the pivotal assembly, inter alia comprising the swing arm and the optical scanning unit, is disposed on the pivotal axis and the two coils are disposed diametrically on both sides of the pivotal axis and exert equal pivotal forces which act in one plane which is perpendicular to the pivotal axis and which extends through the center of mass. The center of mass is disposed midway between two ball-bearings (20, 21).

Abstract: An optical scanning device scans recording tracks on a record carrier with the aid of a beam of radiation, while an objective, which concentrates the beam of radiation to a scanning spot, performs automatic electrically controlled movements in a direction perpendicular to the plane of the record carrier with the aid of a focussing bearing arrangement, so as to ensure a continuous focussing of the scanning spot on the recording tracks. Moreover, in order to follow the oscillations of the recording track, the objective also performs electrically controlled movements which are such that the scanning spot moves at least substantially parallel to the plane of the record carrier.