Patent ID: 6600313
Filing Date: 2003-07-29
Classification: G06K,G07D,G11B

Abstract:
In a system for reading an elongate magnetic data carrier attached to or embedded in an article, including a read head and a data carrier, the read head being adapted to have a track width having a lateral extent perpendicular to the direction of movement of the data carrier greater than the width of the said data carrier perpendicular to the direction of movement of the data carrier, the improvement comprising the read head being constituted by an active read head having means for providing an a/c energising magnetic field and a detection circuit arranged so that the active read head including the means for providing the a/c energising magnetic field and the detection circuit can be located on the same side of the data carrier, the lateral extent of the active read head being at least twice the lateral width of the data carrier, thereby producing a magnetic field which results in use in a signal, detected by said read head from said data carrier, having an amplitude which varies by less than 50% for head to data carrier spacings of from 0 to 60 microns.