MOBILE EQUIPMENT FOR A VIDEO DISC RECORDING SCANNER AND VIDEO DISC RECORDING SCANNER COMPRISING SUCH EQUIPMENT

摘要

The track of a videodisk is followed by a reading light beam produced by a device comprising a reading head fixed on a carriage which forms part of the moving system of a videodisk reader-recorder and is capable of radial displacement along the disk. An objective support frame is capable of displacement in a vertical direction with respect to the carriage in order to maintain focusing of the reading beam and of rotational displacement with respect to the carriage about a transverse axis at right angles to the radial and vertical axes in order to maintain the light beam on the track-following path. Flat coils located vertically in a plane parallel to the carriage path and placed within air-gaps of magnetic circuits serve to develop vertical forces which lift the reading head and initiate the vertical and rotational displacements by means of a differential supply circuit.