Browse Prior Art Database

Higher Density Magnetic Stripe Card

IP.com Disclosure Number: IPCOM000038469D
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Double, GP: AUTHOR

Abstract

This article describes an identification or credit-type card having a magnetic stripe with orthogonally oriented layers of magnetic material. This arrangement permits a substantial increase in stored data within the same stripe area while still allowing the standard 3-track format to be utilized as before. A standard magnetic stripe typically is fabricated by depositing a thin layer of iron oxide particles in a binder onto a MYLAR*-type substrate. The particles are oriented along the direction of the tape length by a magnetic field, while the binder is still fluid. To fabricate a stripe according to this disclosure, the first layer of iron oxide particles is deposited onto a substrate using, for example, a polyurethane solvent type of binder.

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Higher Density Magnetic Stripe Card

This article describes an identification or credit-type card having a magnetic stripe with orthogonally oriented layers of magnetic material. This arrangement permits a substantial increase in stored data within the same stripe area while still allowing the standard 3-track format to be utilized as before. A standard magnetic stripe typically is fabricated by depositing a thin layer of iron oxide particles in a binder onto a MYLAR*-type substrate. The particles are oriented along the direction of the tape length by a magnetic field, while the binder is still fluid. To fabricate a stripe according to this disclosure, the first layer of iron oxide particles is deposited onto a substrate using, for example, a polyurethane solvent type of binder. The particles in this first layer are oriented with a magnetic field at right angles to the length of the stripe and fixed into position by the binder. The magnetic particles have a high anisotropy and a coercivity of at least 300 Oersteds. A second thin (about 200-microinch) magnetic layer is added to the stripe in the conventional manner with the iron oxide particles oriented along the length of the stripe. The binder of the second layer is chosen so as not to disturb the binder of the first layer. A second binder of the thermoplastic type is effective for this purpose. The double layer stripe is now encoded, by standard magnetic writing techniques, along the length of the stripe using an inductive or other suitably shielded write head. Because of the orientation of the magnetic particles, the longitudinal encoding of a standard write head aligns magnetic domains primarily in the top layer. The stripe then may be encoded a second time using a suitably shielded bank of write heads oriented tran...