| 摘要 |
<p>PURPOSE:To obtain a magnetic card with magnetic bar codes having extremely high safety by providing the surface of a recording layer with magnetic patterns consisting of a soft magnetic material which is magnetically satd. by the magnetic field intensity higher than the magnetic field intensity at which a high permeability magnetic layer is magnetically satd. CONSTITUTION:This magnetic card 1 is formed by successively providing the surface of a nonmagnetic substrate 2 with a magnetic layer 3 and the high permeability magnetic layer 4 and providing the surface of the high permeability magnetic layer 4 with the magnetic patterns 5. The soft magnetic material having the saturation magnetic field intensity higher than the saturation magnetic field intensity of the magnetic material used for the high permeability magnetic layer 4 is used for the magnetic patterns 5. Namely, the magnetic patterns 5 have the high magnetic field intensity at which the magnetic material is magnetically satd. and, therefore, if the bias current is increased, the output voltage increases successively in proportion to this increased. On the other hand, the magnetic layer 4 is lower in the magnetic field intensity at which the magnetic material is magnetically satd. than the patterns 5 and, therefore, the generated noise voltage is satd. at the low bias current value. Then, the magnetic patterns are readable in the state of good SN.</p> |
