EP0961301B1 - A magnetic marker - Google Patents

A magnetic marker Download PDF

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Publication number
EP0961301B1
EP0961301B1 EP98953009A EP98953009A EP0961301B1 EP 0961301 B1 EP0961301 B1 EP 0961301B1 EP 98953009 A EP98953009 A EP 98953009A EP 98953009 A EP98953009 A EP 98953009A EP 0961301 B1 EP0961301 B1 EP 0961301B1
Authority
EP
European Patent Office
Prior art keywords
magnetic
magnetic material
soft magnetic
marker
soft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP98953009A
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German (de)
English (en)
French (fr)
Other versions
EP0961301A1 (en
EP0961301A4 (en
Inventor
Shinji 203 Majorikahausu FURUKAWA
Shuji 13-403 Kangetsukyodanchi UENO
Kenji Amiya
Toshiyuki Hirano
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Unitika Ltd
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Unitika Ltd
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Filing date
Publication date
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Publication of EP0961301A1 publication Critical patent/EP0961301A1/en
Publication of EP0961301A4 publication Critical patent/EP0961301A4/en
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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
    • G08B13/2408—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using ferromagnetic tags
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428—Tag details
    • G08B13/2434—Tag housing and attachment details
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428—Tag details
    • G08B13/2437—Tag layered structure, processes for making layered tags
    • G08B13/2442—Tag materials and material properties thereof, e.g. magnetic material details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/0302—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions
    • H01F1/0304—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions adapted for large Barkhausen jumps or domain wall rotations, e.g. WIEGAND or MATTEUCCI effect
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H01F1/153—Amorphous metallic alloys, e.g. glassy metals
    • H01F1/15391—Elongated structures, e.g. wires

Definitions

  • the present invention relates to a magnetic marker to be used in an electronic apparatus for monitoring articles.
  • a special marker is attached to a target article, and such a monitor discriminates the existence of the article according to a signal generated due to the marker.
  • the magnetic system has been used recently widely because a marker can be supplied at a low price.
  • the magnetic system is roughly classified into a type utilizing magnetostrictive vibrations and a type utilizing hysteresis characteristic.
  • a material including an Fe-based amorphous metallic wire is used as a magnetic marker.
  • a detection system is installed in an area where articles are monitored, and an ac magnetic field of 73 Hz, for example, is generated as an inquiry signal from an exciting coil.
  • an ac magnetic field of 73 Hz for example, is generated as an inquiry signal from an exciting coil.
  • the above-mentioned material of the metallic wire is characterized in that its magnetization is very stable in a longitudinal direction, and the magnetization is reversed simultaneously just as the magnetic field reaches a critical value and the flux reversal is completed in a moment.
  • This characteristic is bistable and is often called as large Barkhausen reversal. Since when such a material is excited by a great amplitude, a discontinuous and extremely abrupt step of the magnetization is observed in a hysteresis loop, and it can be discriminated. When the magnetization is abruptly reversed in the marker, a very high pulse voltage is induced in the detection coil.
  • the induced voltage waveform is extremely unique, in comparison with other general magnetic materials, such as an iron plate used for a shopping basket, it can be discriminated easily.
  • frequency analysis of the induced voltage waveform is performed, and according to amplitudes and generating timing of higher harmonics it is decided whether or not the marker exists and it is also decided whether or not generation of a warning is necessary.
  • a magnetic marker including a Co-based amorphous metallic ribbon and the like is used. They are known as so-called high permeability materials, and since their magnetostriction and magnetocrystalline anisotropy are small and a coercive force is low, they are magnetized very easily. When these materials are magnetized by magnetic field of a great amplitude, a hysteresis loop is observed to have a very narrow width and to change continuously.
  • an AC magnetic field is generated by an exciting coil in a monitor area, and a voltage induced to a detection coil is captured as a signal.
  • the AC magnetic field applied in this system has a combination of a plurality of frequencies of, for example, 25 Hz, 1.5 kHz and 2.5 kHz.
  • a pulse voltage which includes a frequency component of the sum of or the difference between 1.5 kHz and 2.5 kHz is induced in the detection coil. Therefore, if the magnitude of a voltage signal having a frequency of 4 kHz obtained by adding 1.5 and 2.5 kHz is not less than a predetermined value, for example, it is judged that the magnetic marker exists. Further, in this system, a low-frequency magnetic field of 25 Hz is superposed. Since this magnetic field magnetically saturates the marker at 25 Hz, the above mixed frequency signal of the sum or difference is generated only at a zero-crossing point in the magnetic field of 25 Hz. Therefore, sensitivity of the system can be guaranteed by checking the generation of the mixed frequency signal and a phase of the magnetic field of 25 Hz.
  • magnetic markers exclusive for respective types have been used. Namely, in a system represented by the system disclosed in Japanese Patent Publication No. 3-27958 (1991), an Fe-based amorphous metallic wire showing the large Barkhausen reversal was used, and a Co-based amorphous metallic thin ribbon which is a high permeability material was used in such a system as disclosed in Japanese Patent Publication No. 3-55878 (1991).
  • a magnetic marker can be sensitively used particularly both in a so-called large Barkhausen type system as disclosed in Japanese Patent Publication No. 3-27958 (1991) and in a so-called high permeability type system as disclosed in Japanese Patent Publication No. 3-55878 (1991).
  • An object of the present invention is to provide a small-size magnetic marker which can be sensitively used particularly both in a so-called large Barkhausen type system and in a so-called high permeability type system.
  • the inventors of the present invention find that the above problem can be solved by using a magnetic marker made of a soft magnetic material whose magnetic characteristic is limited carefully, to attain to the present invention.
  • a magnetic marker of the present invention comprises a soft magnetic material capable of generating abrupt magnetization reversal, and its length is not longer than 70 mm.
  • the soft magnetic material When an external alternating magnetic field of amplitude not larger than 0.2 Oe is applied, the soft magnetic material generates abrupt magnetization reversal with a magnetic flux change of not less than 8.0 x 10 -9 Wb.
  • the soft magnetic material generates the abrupt magnetization reversal when the magnetic field amplitude is fluctuated by an amount equal to or lower than 0.1 Oe.
  • an amount of magnetic flux radiated around the soft magnetic material accompanying the abrupt magnetization reversal is not less than 8.0 x 10 -9 Wb.
  • the soft magnetic material has a difference between signal amplitudes at 1.5 kHz and at 3.5 kHz smaller than -3 dBm when the sinusoidal magnetic field of amplitude of 1.5 Oe is applied at frequency of 73 Hz.
  • the soft magnetic material is, for example, a wire.
  • the soft magnetic material is, for example, a ribbon.
  • the soft magnetic material is for example, a thin film.
  • the magnetic marker for example, two kinds of the soft magnetic material are arranged close to each other.
  • a hard magnetic material having coercive force larger than the soft magnetic material is arranged near the soft magnetic material.
  • the magnetic marker of the present invention is a small-sized magnetic marker whose length is not longer than 70 mm.
  • the magnetic marker includes the soft magnetic material, and the soft magnetic material has a characteristic such that when an external alternating magnetic field is applied and its magnetic field amplitude exceeds a certain critical value, the abrupt magnetization reversal occurs.
  • the magnetic field amplitude where the magnetization of the soft magnetic material is reversed is not higher than 0.2 Oe, and the fluctuation in the critical magnetic field is not higher than 0.1 Oe, and a change of the magnetic flux radiated externally according to the abrupt magnetization reversal is not less than 8.0 x 10 -9 Wb.
  • the magnetic marker of the present invention includes the soft magnetic material which can show abrupt magnetization reversal by applying a weak magnetic field
  • the magnetic marker can be utilized suitably in a plurality of electronic anti-theft systems such as a system utilizing a large Barkhausen effect element and a system utilizing a high permeability element.
  • a magnetic marker of the present invention is small, namely, its length is not longer than 70 mm so that it is applicable to factory sticking.
  • the length is preferably not longer than 50 mm, and more preferably not longer than 25 mm. Its lower limit is not particularly restricted, but since a demagnetizing field of a magnetic material becomes strong, it is not actually preferable that the length is not longer than 10 mm.
  • the magnetic marker of the invention includes the soft magnetic material which can reverse the magnetization abruptly when the amplitude of an ac magnetic field applied to the magnetic marker exceeds a critical value.
  • the abrupt magnetization reversal means that the direction of the magnetization of the soft magnetic material is changed in a very short time or in a very small change in magnetic field.
  • a step-like change region is observed.
  • Such step-like magnetization reversal has a feature that it is affected by the largest amplitude of the magnetic field applied to the material.
  • materials which are called as large Barkhausen reversal materials generally cause abrupt magnetization reversal at a particular critical magnetic field, and the hysteresis curve shows a step-like change.
  • the magnetization is not reversed at a magnetic field smaller than the critical one, and no hysteresis is observed.
  • a material shows magnetization reversal at a relatively small magnetic field but the change is smooth and the hysteresis curve is continuous.
  • abrupt magnetization reversal appears, and the hysteresis curve has a step-like change.
  • a material of both cases can be used as the magnetic marker of the invention because abrupt magnetization change appears at a magnetic field equal to or larger than the critical value.
  • the abruptness can be evaluated, for example, by frequency analysis of the magnetic pulses radiated to the surrounding accompanied by the abrupt magnetization reversal.
  • the magnetization of a magnetic material When the magnetization of a magnetic material is reversed, the magnetic field is radiated secondarily to the surrounding.
  • the magnetization reversal When the magnetization reversal is abrupt, the radiating magnetic field is changed instantaneously.
  • a coil When a coil is put near the magnetic material, an electric voltage pulse is induced in the coil.
  • the frequency analysis of the electric voltage pulse signal is performed, and signal amplitude at various frequencies and ratios thereof are compared in order to evaluate the abruptness of the magnetization reversal. That is, the magnetization reversal is evaluated to be more abrupt as the amplitude at a higher frequency is stronger.
  • the amplitude is evaluated in a generalized way by normalization with use of a ratio of signal amplitudes at various frequencies relative to the that at the same frequency as that of the magnetic field to be applied, where influence of the specifications of the measurement apparatus, the size of the magnetic materials and the like are decreased.
  • An approach which uses a ratio of signal amplitudes at two frequencies sufficiently higher than the exciting basic frequency is a simply evaluation method. For example, when a sinusoidal magnetic field of amplitude of 1.5 Oe at frequency of 73Hz is applied to a magnetic material, the abruptness of magnetization reversal can be evaluated with a difference between signal amplitudes at 1.5 kHz and at 3.5 kHz.
  • the difference is smaller than -3 dBm, it is decided that very abrupt magnetization reversal happens, and the material is suitable for the invention. As the difference becomes smaller, the magnetic material is more suitable, and it is more preferable that the difference is equal to or smaller than -2 dBm.
  • the coercive force generally has a tendency to depend on amplitude of an exciting field, and the above-mentioned value approximately corresponds to the coercive force when the magnetic marker is excited by the amplitude of 1 Oe.
  • the dependence of the coercive force on the exciting field strength is small. For example, a difference in coercive force when the marker is excited by 1 Oe and by 5 Oe falls within 50 % of the coercive force when the magnetic marker is excited by 5 Oe.
  • the coercive force depends on an exciting frequency, and it is preferable that a difference in the coercive forces when the marker is excited, for example, by 73 Hz and by 1 kHz falls within 50 % of the coercive force when excited by 1 kHz.
  • a critical magnetic field necessary for the magnetization reversal exists in the soft magnetic material to be used for the magnetic marker of the present invention, and discontinuous magnetization reversal behavior is shown around the critical magnetic field.
  • the critical magnetic field amplitude is preferably not larger than 0.15 Oe, and more preferably not larger than 0.1 Oe.
  • a change in the magnetic flux radiated by the soft magnetic material included in the marker due to the abrupt magnetization reversal should be not less than 8.0 x 10 -9 Wb.
  • the magnetic flux change is preferable not smaller than 9.0 x 10 -9 Wb, and more preferably not smaller than 10.0 x 10 -9 Wb.
  • the magnetic flux change is measured in the following manner.
  • the change in the reversal magnetic field in this case means that when an alternating field with uniform amplitude is applied to the same magnetic marker repeatedly, the magnetic field strength for the magnetization reversal of the soft magnetic material in the magnetic marker changes in each cycle. Its value is evaluated in the following manner in the present invention.
  • the magnetization reversal field strength is measured continuously in 20 cycles, and an average of the magnetization reversal field strength in positive and negative cycles is calculated.
  • absolute values of differences between average magnetization reversal field strength in positive and negative cycles and the actual magnetization reversal field strength are calculated, and a sum of the results is divided by 40.
  • the obtained value is defined as the fluctuation in the reversal magnetic field.
  • the fluctuation in the reversal magnetic field exceeds 0.1 Oe, the detection sensitivity is lowered extremely in the so-called large Barkhausen type system disclosed in Japanese Patent Publication No. 3-27958 (1991), so this is not preferable.
  • the magnetic marker of the present invention composed of the soft magnetic material having the above magnetic characteristic can be realized by various structures, so it is not particularly limited in the present invention.
  • the soft magnetic materials suitable for the magnetic marker of the present invention are as follows.
  • an amorphous metallic wire is prepared by an in-rotating-liquid melt spinning method disclosed in Japanese Patent laid open Publication No. 56-165016 (1981), or an amorphous metallic ribbon is prepared by a single roll apparatus disclosed in Japanese Patent Publication No. 3-27958 (1991), and the wire or ribbon is used suitably as the soft magnetic material of the magnetic marker of the present invention.
  • the critical magnetic field of the magnetization reversal and its magnetic flux change can be adjusted arbitrarily.
  • the wire or ribbon is subject to a wire drawing process, rolling process, slit process or the like before the heat treatment, it can be formed into a desired form, and thus such processes are effective because a demagnetizing field can be adjusted.
  • a thin film of magnetic material can be used suitably as the soft magnetic material of the present invention.
  • Such a magnetic thin film material is disclosed, for example, in Japanese Patent Laid-Open Publication No. 4-218905 (1992). According to such a document, a soft magnetic thin film having an abrupt magnetization reversal behavior with a critical value can be provided, so it is suitable for the object of the present invention.
  • Figs. 1A to 1F show various magnetic markers schematically.
  • Fig. 1A shows a magnetic marker comprising a soft magnetic wire 12 adhered to a polyethylene terephthalate (PET) film
  • Fig. 1B shows a magnetic marker comprising a soft magnetic thin ribbon 14 adhered to a PET film
  • Fig. 1C shows a magnetic marker comprising a soft magnetic thin film 18 adhered to a PET film 10.
  • PET polyethylene terephthalate
  • the magnetic marker of the invention can be constructed by combining two kinds of magnetic materials, and this can be expected to improve the performance.
  • two pieces of soft magnetic material 16 are arranged at two ends of a linear soft magnetic material 12 in contact with each other. Then, the marker has a higher sensitivity for an anti-theft system than a marker comprising only the single long magnetic material, and a more compact magnetic marker can be provided. It is considered that the two pieces of soft magnetic material 16 function as a magnetic yoke which concentrates the adjacent magnetic field to guide to the linear magnetic material.
  • a similar advantage is also observed when a linear magnetic material 12 is combined with a magnetic thin film 18 on a PET film 10, as shown in Fig. 1E.
  • the linear magnetic material is put on a sheet of magnetic thin film.
  • the advantage is remarkable when the magnetic thin film has magnetic anisotropy wherein the longitudinal direction of the linear magnetic material is along to the magnetically hard axis of the thin film, and good performance can be obtained on the marker.
  • a length of the above soft magnetic material is not particularly limited. However, it is desirable that because the above magnetic material cannot become longer than the magnetic marker, its length is desired at least not longer than 70 mm, preferably 10 to 70 mm, and more preferably 20 to 60 mm.
  • a demagnetizing field influences the soft magnetic material Since a demagnetizing field influences the soft magnetic material, a relationship between a cross section and a length thereof is important.
  • a wire material for example, a material whose diameter is 30 ⁇ m and length is 10 mm can be utilized suitably.
  • the diameter is 100 ⁇ m, if the length is not longer, the characteristic of the material has a tendency to be deteriorated.
  • the length is preferably equal to or longer than 20 mm, for example.
  • a ribbon and a thin film have the same tendency in this case.
  • the intensity of a signal generated from the magnetic marker has a tendency to depend strongly on a volume, particularly, on a cross section of the soft magnetic material. Namely, it is desired that the size of the soft magnetic material is determined by taking a level of required signal intensity into consideration.
  • the marker does not react or it is deactivated. Since the marker can be deactivated or activated by a simple device, a user can apply the electronic article monitor system to various uses widely.
  • a metallic ribbon such as available from Arnochrome (Arnold) or Semivac (Vacuum Schmelze ) are suitably used.
  • a paint including magnetic powders, a hard magnetic foil such as Ni and the like can also be utilized.
  • the magnetic marker of the present invention is used normally in forms of a label, a tag and the like with an adhesive layer, but the present invention is not limited to these forms.
  • a magnetic marker of a label will be described as an example.
  • the soft magnetic material which will generate a signal in the monitor area is contained between two sheets of paper or plastic film.
  • An adhesive layer is applied to an inner surface of the paper or film so that the soft magnetic material is held thereto.
  • the hard magnetic material for the deactivating function is included further, it is arranged so as to closely contact with the soft magnetic material, and it is arranged between the two sheets of paper or plastic film.
  • Metallic ribbons having characteristics shown in Table 1 are prepared by using a single roll apparatus.
  • the preparation conditions of the single roll method are as follows. A mother alloy of about 200 g is inserted into the quartz nozzle, and it is melted with a high frequency in argon atmosphere. The argon gas pressure is increased to about 2 kg/cm 2 , and liquid metal is ejected from the nozzle hole of a diameter of about 300 ⁇ m. The liquid metal is ejected onto an outer peripheral surface of a copper roll of a diameter of 200 mm rotating at about 1200 rpm so as to be rapidly cooled to become solid, and it is wound around a reel by a winding mechanism.
  • Structures of the above samples are measured by X-ray diffraction, and only a halo pattern is observed on all the samples. Then, the structures are identified as an amorphous phase. Moreover, as for the sample shape, cross sections in ten points of the samples are observed by an OPTIPHOT optical microscope of Nikon, and an average value of the cross sections is measured. A magnetic hysteresis characteristic of each sample is measured by an AC magnetic hysteresis measurement apparatus ACBH-100K of Riken Electron Co. Ltd.
  • a magnetic field strength and a magnetic flux change when the magnetization is reversed are measured.
  • frequency analysis is performed on the magnetic signals generated by a sample.
  • a function generator 3341A of Hewlett Packard and a high speed power amplifier 4025 of NF Electronics Instrument are connected to a Helmholtz coil of 400 mm of diameter to generate a sinusoidal magnetic field of 73 Hz of frequency and 1.5 Oe of amplitude at the center position.
  • a detection coil of 200 turns is put in the center positions, and a sample is inserted into the detection coil. An output of the detection coil is subjected to frequency analysis with a dynamic signal analyzer 35665A of Hewlett Packard.
  • Examples 1 through 5 as the magnetic markers of the present invention where discontinuous and abrupt magnetization reversal occurs in a magnetic field smaller than 0.2 Oe and the magnetic flux changes at the reversal is larger than 8.0 x 10 -9 Wb, shows sufficient sensitivity in both systems of Sensormatic and of Esselte Meto .
  • Example 3 where the magnetization reversal field changes by more than 0.1 Oe, its sensitivity is lower in the system of Sensormatic than the other examples.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Burglar Alarm Systems (AREA)
  • Thin Magnetic Films (AREA)
EP98953009A 1997-11-17 1998-11-11 A magnetic marker Expired - Lifetime EP0961301B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP31498397 1997-11-17
JP31498397 1997-11-17
PCT/JP1998/005069 WO1999026257A1 (fr) 1997-11-17 1998-11-11 Marqueur magnetique

Publications (3)

Publication Number Publication Date
EP0961301A1 EP0961301A1 (en) 1999-12-01
EP0961301A4 EP0961301A4 (en) 2001-07-18
EP0961301B1 true EP0961301B1 (en) 2007-04-11

Family

ID=18060017

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98953009A Expired - Lifetime EP0961301B1 (en) 1997-11-17 1998-11-11 A magnetic marker

Country Status (4)

Country Link
EP (1) EP0961301B1 (es)
DE (1) DE69837528T2 (es)
ES (1) ES2284215T3 (es)
WO (1) WO1999026257A1 (es)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2847065B1 (fr) * 2002-11-13 2005-04-15 C P C Packaging Etiquette pour la protection d'un article contre le vol
FR2847064B1 (fr) * 2002-11-13 2005-02-11 C P C Packaging Etiquette pour la protection d'un article contre le vol
AT511332B1 (de) * 2011-08-11 2012-11-15 Suess Dieter Dr Methode und vorrichtung zur diskriminierenden detektion von behältern für die zubereitung von nahrungsmitteln in extraktionsmaschinen mittels magnetisierbarer materialien
JP2014171044A (ja) * 2013-03-01 2014-09-18 Yokohama National Univ 電気パルス発生装置、及び電気パルス発生装方法
EP3451309A4 (en) * 2016-04-28 2019-07-03 Aichi Steel Corporation MAGNETIC MARKER AND FAHRASSISTENZSYSTEM
GB2585034A (en) * 2019-06-25 2020-12-30 Endomagnetics Ltd Hyperthermia implants and a method and system for heating the implant
US11166782B1 (en) 2020-07-19 2021-11-09 Sirius Medical Systems B.V. Implantable marker and a method of implanting markers

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4660025A (en) * 1984-11-26 1987-04-21 Sensormatic Electronics Corporation Article surveillance magnetic marker having an hysteresis loop with large Barkhausen discontinuities
DE3545647A1 (de) * 1985-12-21 1987-06-25 Vacuumschmelze Gmbh Deaktivierbares sicherungsetikett fuer diebstahlsicherungssysteme
US5015993A (en) * 1989-06-29 1991-05-14 Pitney Bowes Inc. Ferromagnetic alloys with high nickel content and high permeability
US5304983A (en) * 1991-12-04 1994-04-19 Knogo Corporation Multiple pulse responder and detection system and method of making and using same
JPH09134817A (ja) * 1995-11-08 1997-05-20 Unitika Ltd 磁気マーカ

Also Published As

Publication number Publication date
EP0961301A1 (en) 1999-12-01
DE69837528T2 (de) 2007-08-09
DE69837528D1 (de) 2007-05-24
ES2284215T3 (es) 2007-11-01
EP0961301A4 (en) 2001-07-18
WO1999026257A1 (fr) 1999-05-27

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