Unitika Ltd.

Kazuki Oka

Shinji Furukawa

Nobuyoshi Yano

Isamu Ogasawara

Akira Tanimura

Toshiyuki Hirano

A magnetic marker which comprises a flexible organic polymer substrate having an anisotropic thermal shrinking property and a soft magnetic thin film having uniaxial magnetic anisotropy. The angle formed between the direction in which the organic polymer substrate has the highest degree of thermal shrinkage and the direction of magnetic easy axis in the soft magnetic thin film is in the range from 50.degree. to 90.degree.. The marker is a thin film of a simple structure, yet exhibits satisfactory magnetic characteristics. A roll having a plurality of magnetic markers, each comprising an organic polymer substrate and a soft magnetic thin film formed transversely on the surface, can be manufactured by a process relying upon the combination of (i) a roll coater method and (ii) a sputtering technique. In the process, the organic polymer substrate is set and continuously transported such that the direction in which the organic polymer substrate experiences the highest degree of thermal shrinkage is not greater than 40.degree. with respect to the direction of its travel. Furthermore, the thickness of the soft magnetic thin film that is deposited per unit of the cathode as the result of a single pass of the organic polymer substrate over the cathode does not exceed 0.4 .mu.m. The process is capable of continuous production of magnetic markers having satisfactory magnetic characteristics and advantageously enables easy manufacture of a roll having a plurality of such magnetic markers arranged transversely thereon.

Magnetic marker and process for manufacturing a roll having a plurality

A compact and superior magnetic marker for an electronics apparatus for surveillance of article comprises at one or more wire members and a plane member contacting substantially directly to each other. An angle of the magnetic easy axis of the plane member relative to the longitudinal direction of the wire member is between 40.degree. and 90.degree. to show large Barkhausen reversal. An influence of demagnetizing field can be reduced by using the simple structure. The magnetic marker can be produced continuously at a low cost.

Magnetic marker and manufacturing method therefor

A thin-film magnetic material is formed on a polymer substrate. The material exhibits large Barkhausen discontinuity without intentional application of external tensile or torsional stress. The thin-film material may be produced by a sputtering technique wherein the normal to the substrate is directed obliquely to a target member. A biasing magnetic field in proximity to the substrate may also be used during film formation, and the substrate may be supported by a curved holder or a cylindrical roll-to-roll apparatus. The thin-film thus produced may be used as a marker in an article surveillance system or as a magnetic sensor.

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Kyoto, Japan

Kazuki Oka