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:
Apr. 15, 1980
Filed:
Jun. 26, 1978
Applicant:
Inventor:
Ralph R Pearce, West Drayton, GB;
Assignee:
EMI Limited, Hayes, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06K / ; G06K / ;
U.S. Cl.
CPC ...
235493 ; 360-2 ; 360 40 ; 360134 ;
Abstract
Magnetic recording media including permanent structures of aligned acicular particles have been proposed as a means of identifying and authenticating a medium. A structure which has an improved remanence difference signal is described. A method of making and examining such a structure is described. Arrangements of such media and record/read-out apparatus by which information can be recorded and read-out without interference from the structural remanence differences are described. The use of the media for security documents such as credit cards is described.