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:
Oct. 14, 1980
Filed:
May. 31, 1979
Applicant:
Inventor:
Cyril A Lee, Littlewick Green, GB;
Assignee:
E M I Limited, Hayes, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06K / ; G06K / ; G11B / ; G11B / ;
U.S. Cl.
CPC ...
235449 ; 235493 ; 360-2 ; 360 18 ; 360 25 ; 360 57 ;
Abstract
A magnetizable anisotropic material layer having a pattern of regions of differently aligned material has an initial pattern of remanent magnetization, when manufactured by applying directional magnetic fields. This pattern is not easily restored, and is generally impossible to restore, after demagnetization or remagnetization. By preserving the residual pattern and selectively removing it in use by the application of a magnetic field, a security feature is provided. A secure document system using such a feature is provided.