The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 20, 1984
Filed:
Dec. 03, 1980
Applicant:
Inventors:
Eberhard Koester, Frankenthal, DE;
Joachim Hack, Ludwigshafen, DE;
Manfred Steuerwald, Frankenthal, DE;
Assignee:
BASF Aktiengesellschaft, Ludwigshafen, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
360-2 ; 235493 ;
Abstract
A process for authenticating recording media which are to be safeguarded against falsification and which possess a layer of exchange-anisotropic magnetic material, by determining the residual recording which is left over, because of the exchange anisotropy of the magnetic material, from a recording of a sequence of signals after exposure of the material to a specific temperature cycle and, subsequently, to a magnetic AC field which decreases to zero, and an apparatus for carrying out the said process.