| 摘要 |
<p>PURPOSE:To prevent unauthorized use by forming a discontinuous pattern by a required system in a thin magnetic layer disposed on a magnetic recording layer and using this pattern as unauthorized use preventing information. CONSTITUTION:A magnetic layer 2 of a magnetic substance having 200-5,000 Oe coercive force, an adhesion assisting layer 3, a thin magnetic layer 4 and a protective layer 5 are laminated on a nonmagnetic substrate 1. The layers 4, 5 are then destructed by irradiation at a high temp. of >=300 deg.C to form a discontinuous pattern 7 of ID information. This ID information is made difficult to erase or rewrite and the objective magnetic recording medium capable of easily and satisfactorily preventing unauthorized use is produced.</p> |
