Minnesota Mining and Manufacturing Company

3m Innovative Properties Company

Richard E Fayling

Gregory F Jacobs

Bernard A Gonzalez

Thomas J Dahlin

David M Hopstock

Robert L Keech

Richard G Newell

Gary W Clark

Claud M Lacey

Magnetic, conformable articles for use with traffic bearing surfaces are disclosed which comprise an organic binder having magnetic particles distributed therein. The articles may be employed in intelligent vehicle guidance systems, and in systems to guide other mobile objects such as farm animals, pets, or visually impaired pedestrians. Methods of making the articles and methods of using the systems to control and/or guide a mobile object using the magnetic field generated from the articles are also described.

Conformable magnetic articles for use with traffic bearing surfaces methods of making same systems including same and methods of use

A conformable magnetic article for underlayment beneath a traffic-bearing surface which sends a magnetic signal to a sensor traveling over the traffic-bearing structure. The magnetic article comprises at least one conformable magnetic layer comprising a binder and a sufficient amount of magnetic particles dispersed within the binder to provide a magnetic signal through the traffic-bearing structure to a sensor.

Conformable magnetic articles underlaid beneath traffic-bearing surfaces

Some prior magnetic recording tapes have a backside layer of electrically conductive particles and friction-imparting nonmagnetic particles in a nonmagnetic binder. The novel tape differs in that the nonmagnetic particles are replaced by high-H.sub.c ferromagnetic particles, onto which may be recorded a distinctive magnetic pattern. This provides a 'magnetic watermark' that should protect recordings from being counterfeited, because if one were to copy a recording onto ordinary magnetic recording tape, the copy would lack the 'watermark'. This should inhibit unauthorized copying of video recordings such as motion pictures.

Counterfeit-resistant magnetic recording tape

A system for contact duplication is disclosed wherein anhysteretic magnetization of a copy medium occurs using an anisotropic master medium wherein the two media are held in surface contact and an AC bias magnetic field is applied along the hard axis of the master media.

Contact duplication system using anisotropic magnetic recording media

An electromagnetic sensor and memory device for employment with a reader for magnetically encoded cards has a plurality of bit indicators that detect magnetized data bits in such cards. Each bit indicator is formed from a ferromagnetic core magnetizable to either of two opposite stable magnetized states that switch from one stable state to the other upon application of an appropriate magnetizing field. A control element disposed through the core serves to provide the magnetizing field for switching the stable state of the core and also serves as a sensing means for detecting each switch between stable states. In a modified embodiment, bias magnetizing field sources are employed with the bit indicators to provide a variety of bit sensing operations.

Electromagnetic sensor and memory device

A magnetizable layer having an H.sub.c of at least 3000 oersteds pre-encoded with digital data is permanently bonded to the face of a document and has a permanent protective overlayer which, if magnetizable, has relatively low H.sub.c and can be used for recording transaction data.

Tamperproof magnetically readable label

A system using a recording medium for accumulating data to be fed to electronic data processing equipment. The system includes homogeneous permanent magnet material master source documents capable of being magnetized throughout in discrete patterns providing external magnetic fields representative of encoded data. The permanent magnet material has a coercivity of not less than 1000 oersteds and a maximum energy product of not less than 5 .times. 10.sup.5 gauss-oersteds. The data is recorded onto a recording medium momentarily positioned adjacent the documents. The data is subsequently sensed from the recording medium to produce electrical signals to be processed in data processing equipment. In one embodiment customer and transaction data are magnetically recorded onto the recording medium.

Data accumulation system

A magnetic recording medium having at least two particle populations that may be either contained in a single layer of magnetic medium or a dual layer of magnetic medium. In a first embodiment one of the particle populations of the medium is formed of conventional magnetic recording particles and the other population is highly anisotropic. In a second embodiment both particle populations are highly anisotropic but they are aligned so that the easy axes of magnetization of the populations are at an angle to one another. Also disclosed is a machine readable magnetic recording document that employs the magnetic recording medium of the present invention, and an apparatus for reading such document and validating the same.

Dual particle population magnetic recording medium

A magnetic recording medium having uniaxially highly anisotropic particles with an easy axis intrinsic coercive force of less than 1900 oersteds. Also disclosed is a machine readable magnetically encoded document employing the medium of the present invention and an apparatus for reading such document and validating the same.

Growing community of inventors

White Bear Lake, MN, United States of America

Richard E Fayling