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Browse Prior Art Database

Magnetic Storage by Particle Reorientation

IP.com Disclosure Number: IPCOM000112196D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+5]

Abstract

The magnetic information encoded on bank cards is not very secure or reliable. The fraudulent user can easily erase the magnetic information with a simple a.c. magnetic tape eraser. A means of encoding is needed which makes the stored information difficult or impossible to erase. It is important, however, that the medium still be readable with the existing magnetic point-of-sale readers and that it is possible to encode the magnetic stripe at the same time the bank embosses the card. Another desirable feature is the use of readily available particulate magnetic media in an organic binder that can be applied to the card by low cost methods.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 77% of the total text.

Magnetic Storage by Particle Reorientation

      The magnetic information encoded on bank cards is not very
secure or reliable.  The fraudulent user can easily erase the
magnetic information with a simple a.c.  magnetic tape eraser.  A
means of encoding is needed which makes the stored information
difficult or impossible to erase.  It is important, however, that the
medium still be readable with the existing magnetic point-of-sale
readers and that it is possible to encode the magnetic stripe at the
same time the bank embosses the card.  Another desirable feature is
the use of readily available particulate magnetic media in an organic
binder that can be applied to the card by low cost methods.

      Disclosed is an encoding system which makes use of thermal
means, for example laser irradiation, to locally heat a previously
oriented magnetic medium in a strong magnetic field so as to locally
reorient the anisotropic magnetic particles in the medium.  The
region with the particles oriented perpendicular to the plane of the
medium produces a magnetic flux transition by changing the "magnitude
of the magnetic flux component normal to the surface of the magnetic
stripe [*].  Prior art methods of encoding the information with a
magnetic recording head have successive regions of the stripe
magnetized in the plane of the stripe in alternating directions.  The
transitions are produced by regions where the magnetic domains are
opposing so that some magnetic flux is di...