EP0604293A1 - Doppelstatus-Dünnfilmmarkierung für elektronische Artikelüberwachung - Google Patents

Doppelstatus-Dünnfilmmarkierung für elektronische Artikelüberwachung Download PDF

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Publication number
EP0604293A1
EP0604293A1 EP93403099A EP93403099A EP0604293A1 EP 0604293 A1 EP0604293 A1 EP 0604293A1 EP 93403099 A EP93403099 A EP 93403099A EP 93403099 A EP93403099 A EP 93403099A EP 0604293 A1 EP0604293 A1 EP 0604293A1
Authority
EP
European Patent Office
Prior art keywords
thin
film
signal
magnetic
marker
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.)
Granted
Application number
EP93403099A
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English (en)
French (fr)
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EP0604293B1 (de
Inventor
Ching-Long C/O Minnesota Mining And Tsai
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.)
3M Co
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Minnesota Mining and Manufacturing Co
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Filing date
Publication date
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Publication of EP0604293A1 publication Critical patent/EP0604293A1/de
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Publication of EP0604293B1 publication Critical patent/EP0604293B1/de
Anticipated expiration legal-status Critical
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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
    • G08B13/2411—Tag deactivation
    • 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
    • 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

Definitions

  • the invention relates to reversibly reactivatable dual status markers useful in magnetic-type electronic article surveillance (EAS) systems.
  • EAS electronic article surveillance
  • an article bearing one of those markers is passed through an interrogation zone of alternating magnetic fields, the magnetization state of the marker is periodically reversed, and a remotely detectable characteristic response (here sometimes called "an alarm signal") is produced.
  • the invention also relates to the manufacture of such markers and to a product that can be used as a control element to afford dual status to a marker of the prior art.
  • Magnetic-type EAS systems are widely used to inhibit the theft of merchandise such as clothing, books, and cassettes.
  • Markers used in such systems typically have comprised elongated ribbons of metal foil that exhibit high permeability and low coercive force to enable their state of magnetization to reverse in the relatively low intensity alternating magnetic fields typically associated with magnetic-type EAS systems.
  • Those fields have average peak intensities of a few Oersteds, typically ranging from about one Oersted at the center to about 20 Oersteds at the edges of the interrogation zone of an EAS system.
  • a remanently magnetizable layer is laminated to such a ribbon and acts as a control element to afford dual status to the marker. It has a passive status when the remanently magnetizable layer is magnetized to prevent the marker from producing an alarm signal when an article to which it is attached is carried through an interrogation zone of an EAS system. It has a sensitized status when the remanently magnetizable layer is demagnetized, thus enabling the marker to produce an alarm signal.
  • the Elder patent also suggests that a disc-shaped marker, which is sufficiently thin, can have a useful demagnetization factor.
  • the marker of Montean '908 also can be bidirectional. It has a specially shaped foil which bears a remanently magnetizable layer that, when magnetized in a predetermined pattern, permits the marker to produce an alarm signal in an interrogation zone. When the remanently magnetizable layer is demagnetized, the marker will not produce an alarm signal.
  • U.S. Patent No. 4,960,651 points out that a marker, when sensitized, should have low demagnetization factors to permit low intensity interrogation fields to be used, and that metal ribbons such as ribbons of permalloy foil must be quite long to achieve low demagnetization factors.
  • the Pettigrew patent concerns a marker that has low demagnetization factors and is made by depositing onto a substrate a magnetic thin-film of low coercive force and high permeability that preferably is from 1 to 5 ⁇ m in thickness.
  • the Pettigrew thin-film marker can be quite thin and more mechanically flexible and hence more robust. By being thin, it can be less conspicuous. Also, it can have a more convenient shape such as the dimension and shape of a price label and can be square or circular.
  • the Pettigrew marker can be made to have dual status by applying a deactivation layer of semi-hard magnetic material to change the effective magnetic properties of the magnetic thin-film of low coercive force so that it is not recognized in an interrogation zone.
  • the deactivation layer employed a thin sheet (col. 15, line 9) or a foil, slurry, needles, or steel wool or mesh (col. 16, lines 15-24).
  • the Pettigrew patent does suggest: "The deactivating material may be fabricated by thin film processes" (col. 6, lines 62-64) but includes no enabling disclosure, instead referring to disclosure for fabricating the magnetic thin-films of low coercivity.
  • an elongated marker may be formed of a strip of alternating sputtered layers of ferromagnetic materials. In that construction, each layer is separated by an evaporated coating of, for example, aluminum oxide. Fearon still emphasizes the necessity of an elongated shape and the subsequent need for appropriate orientation in an interrogation field. See also U.S. Pat. No. 4,682,154 (Fearon).
  • the marker of coassigned U.S. Patent No. 5,083,112 (Piotrowski et al.) comprises a laminate of a plurality of magnetic thin-films deposited on a flexible substrate with an ultrathin nonmagnetic thin-film interposed between adjacent magnetic thin-films.
  • Each of the magnetic thin-films exhibits high permeability and a coercive force sufficiently low so as not to retain any given magnetization state and less than the average intensity of magnetic fields encountered in an interrogation zone, such that upon exposure to such fields, the magnetization state of the marker is periodically reversed and an alarm signal is produced.
  • the easy axis of one of the magnetic thin-films extends in a direction different from that of another (as in Fig. 3) or a magnetic thin-film has more than one easy axis, the marker is bi-directional.
  • the Piotrowski patent demonstrates that a plurality of magnetic thin-films permit the markers to be smaller and yet produce sharper, more intense signals than was possible in the prior art. Its five examples employ from 7 to 15 pairs of magnetic thin-films (e.g., Ni-Fe) and nonmagnetic thin-films (e.g., SiO x ).
  • the Piotrowski marker can include a layer of remanently magnetizable material such as a thin foil of magnetic stainless steel or vicalloy or a dispersion of gamma iron oxide particles.
  • the invention provides a reversibly reactivatable dual status marker for use with a magnetic-type EAS system that produces, in an interrogation zone, alternating magnetic fields having average peak intensities of a few Oersteds.
  • the dual status marker of the invention should be as economical to manufacture as any prior marker, and should be at least as small in area and thinner, more flexible, and more durable than any above-discussed marker without any reduction in performance.
  • the novel marker should function well at thicknesses that are so thin that it can be virtually undetectable when hidden between layers of some garments. As was pointed out in the Montean Patent No.
  • the dual status marker of the invention has a substrate and, supported by the substrate, a signal-producing layer and a signal-blocking layer.
  • the signal-producing layer includes at least one magnetic thin-film having high permeability and a coercive force less than the minimum peak intensity encountered in said zone, such that upon exposure to fields of an interrogation zone, the magnetization state of said at least one magnetic thin-film is periodically reversed and a remotely detectable characteristic response (i.e., an alarm signal) is produced.
  • Said at least one magnetic thin-film should have a total thickness of from 200 to 1000 nm. At total thicknesses substantially below 200 nm, a marker might fail to produce an alarm signal in some magnetic-type EAS systems, while total thicknesses substantially above 1000 nm would increase the cost of the marker without significant benefit.
  • the signal-blocking layer of the novel marker includes at least one remanently magnetizable thin-film having a total thickness at least equal to the total thickness of said at least one magnetic thin-film of the signal-producing layer.
  • the signal-blocking layer should be in substantial contact with and extend over an area of the signal-producing layer and should have a size and coercivity sufficient to prevent the signal-producing layer from producing an alarm signal in the interrogation zone when the signal-blocking layer is magnetized.
  • the novel marker can be produced at reasonable cost.
  • the coercivity of the signal-blocking layer does not exceed 100 oersteds so that it can be demagnetized by a magnetic field that is weak enough not to damage any article to which a marker may be attached, e.g., not to erase any data on the magnetic tape of a cassette.
  • the coercivity of the signal-blocking layer is at least 25 Oersteds to guard against accidental demagnetization or remagnetization.
  • the signal-blocking layer of the novel marker should have adequate thickness to provide enough magnetic flux, when magnetized, to saturate adjacent portions of the signal-producing layer.
  • the total thickness of said at least one remanently magnetizable thin-film preferably is from two to five times the total thickness of said at least one magnetic thin-film of the signal-producing layer.
  • said at least one magnetic thin-film preferably has a total thickness of from 200 to 500 nm, and said at least one remanently magnetizable thin-film is from 800 to 1200 nm in total thickness.
  • electrically conductive, remanently magnetizable thin-films could propagate eddy currents when subjected to interrogating fields of high frequency, and so might have an undesirable shielding effect when demagnetized. Interrogating fields of higher frequency enable a signal-producing layer of the novel marker to produce alarm signals of greater amplitude.
  • the signal-blocking layer has from 3 to 11 pairs of remanently magnetizable thin-films and interposed nonmagnetic thin-films.
  • the novel marker When its signal-producing layer comprises a single magnetic thin-film, the novel marker can produce a signal that is sufficiently sharp and intense to produce alarm signals in most magnetic-type EAS systems now on the market.
  • the signal-producing layer comprises a plurality of magnetic thin-films and interposed nonmagnetic thin-films, the novel marker can produce a sharper, more intense and hence more reliable signal.
  • Preferred magnetic thin-film materials for the signal-producing layer include permalloy, "Sendust,” and amorphous magnetic alloys such as are listed in Re. 32,427 (Gregor et al.) at col. 6, lines 11-18.
  • the signal-blocking layer is in intimate contact with the signal-producing layer so that when the signal blocking layer is magnetized, its magnetic flux is efficiently shunted through the signal-producing layer.
  • an ultrathin nonmagnetic thin-film layer it may be desirable to interpose an ultrathin nonmagnetic thin-film layer. Any such ultrathin nonmagnetic thin-film that is either interposed between the signal-producing and signal-blocking layers, or is interposed between a plurality of magnetic thin-films of the signal-producing layer, should be thinner than the thin-films it is separating and should be as thin as possible, such as from 5 to 20 nm.
  • Remanently magnetizable materials that have been most effective for the signal-blocking layer are Fe-Cr alloys having a Cr content up to about 20 atomic percent. Preferably, the Cr content is from 1 to 15 atomic percent to afford a coercivity of from 25 to 100 Oersteds.
  • Other useful remanently magnetizable materials include Fe-Co-Cr, Fe-Ni-Cr, and Ni-Co alloys and partially oxidized Ni-Fe alloys.
  • Ultrathin nonmagnetic thin-films may be readily formed from an oxide of silicon, aluminum, or the like.
  • Each of the nonmagnetic thin-films, magnetic thin-films of the signal-producing layer, and remanently magnetizable thin-films of the signal-blocking layer can be formed by evaporation, sputtering, sublimation, etc.
  • the signal-blocking layer of the thin-film of the novel dual status marker preferably is discontinuous or, if continuous, is magnetized in an alternating pole pattern by a device such as that of Fig. 23 of Montean Pat. No. 4,746,908, thus better ensuring deactivation of said at least one magnetic thin-film.
  • a discontinuous signal-blocking layer allows the novel marker to be magnetized in any magnetic-type EAS system now on the market, whereas a continuous signal-blocking layer might not become sufficiently demagnetized in apparatus of an EAS system that deactivates a marker by translating it across a unidirectional magnetic field.
  • a continuous signal-blocking layer can be made discontinuous by scoring, or a discontinuous thin-film or thin-films can be applied through masks.
  • Suitable discontinuous patterns are those of the magnetizable material 86 of Fig. 5 of the Piotrowski patent and the magnetizing elements 44 of Fig. 4 of the Gregor patent.
  • the segments of a discontinuous pattern are of substantially uniform size and shape and each has a area of from 1 to 100 mm2.
  • the substrate of the novel marker preferably is flexible, e.g., a polyimide or high-temperature-resistant polyester web from 25 to 50 ⁇ m thick. While polyimide has superb mechanical properties, including stability at elevated temperatures, it is highly hygroscopic, retaining about 1 percent by weight of water. It is necessary to outgas such films prior to deposition. Such outgassing has been obtained by passing the substrate films within a vacuum chamber three times at a rate of approximately 60 cm per minute over a roller heated to 315°C. For some applications, thin metallic foils of nonmagnetic stainless steel, aluminum, and copper can also be used.
  • the substrate can either become a permanent part of the novel marker, or the thin-films can be transferred from substrates to articles which are to be protected against theft, e.g., to the shell of a cassette. Upon doing so, it may be desirable to apply an opaque coating to make the marker invisible.
  • the novel marker can have a variety of shapes, such as the size and shape of a price label, and it can be square or circular.
  • its area preferably is at least 1 cm2, more preferably from 2 to 10 cm2.
  • said at least one magnetic thin-film preferably has a maximum differential permeability of at least 5,000 and a coercive force no greater that 5 Oersteds.
  • FIGS. 1-3 are schematic.
  • FIGS. 1-3 are schematic.
  • a dual status EAS marker 10 has a flexible substrate 12 bearing a magnetic thin-film 14 that has high permeability and low coercive force, e.g., permalloy, and serves as a signal-producing layer.
  • a remanently magnetizable thin-film 16 In contact and coterminous with the magnetic thin-film 14 is a remanently magnetizable thin-film 16 that serves as a signal-blocking layer.
  • the remanently magnetizable thin-film 16 has a discontinuous pattern of squares 18.
  • FIG. 3 shows a second dual status EAS marker 20 that has a flexible substrate 22 on which is deposited a signal-producing layer 23 including a plurality of magnetic thin-films 24, such as permalloy, and ultrathin nonmagnetic thin-films 25, such as SiO x , with an ultrathin nonmagnetic thin-film 25 interposed between adjacent magnetic thin-films 24.
  • a signal-producing layer 23 including a plurality of magnetic thin-films 24, such as permalloy, and ultrathin nonmagnetic thin-films 25, such as SiO x , with an ultrathin nonmagnetic thin-film 25 interposed between adjacent magnetic thin-films 24.
  • a nonmagnetic thin-film 26 In contact and coterminous with the outermost magnetic thin-film 24 is a nonmagnetic thin-film 26 which is covered by a continuous remanently magnetizable thin-film 27 that serves as a signal-blocking layer.
  • a line 30 indicates approximate coercivities of Fe-Cr alloys based on test values 32 on thin-films.
  • a dual status marker as shown in FIG. 3 was prepared using an ion beam sputtering/deposition unit and a glass substrate. Onto the glass substrate was deposited a coterminous thin-film of amorphous Co-based alloy to a thickness of 350 nm. This was then annealed at 350°C for 30 minutes in a unidirectional magnetic field having an intensity of 5 Oe along the plane of the thin-film. In an alternating magnetic field of 10 kHz and an amplitude of 2 Oe, a sample 2.5 cm square had B m 7647 G B r /B m 0.74 H c 0.21 Oe dB
  • an ultrathin Si thin-film over which a signal-blocking layer was applied by depositing five thin-films of an Fe90-Cr10 alloy interposed with four nonmagnetic Si thin-films, all of which were coterminous with the substrate.
  • the remanently magnetizable Fe-Cr thin films afforded dual status to the resulting marker.
  • Each of the Fe-Cr thin-films was 70 nm in thickness, and each of the ultrathin Si thin-films was 10 nm in thickness.
  • the signal-blocking layer was then magnetized to have 12 rows per inch (4.7 rows/cm) of oppositely-directed magnetized regions, thus preventing the marker from producing an alarm signal when exposed to the aforementioned magnetic field. In that field, the hysteresis curve of the signal-producing layer became a minor loop, resulting in a signal too low in harmonic content to be recognized as an alarm.
  • the dual status marker was tested in 3M's Model 3300B magnetic-type EAS system. When its signal-blocking layer was magnetized, the marker was passive and did not produce an alarm signal in the interrogation zone of the EAS system. When the signal-blocking layer was demagnetized, the magnetization state of the signal-producing layer was periodically reversed to produce an alarm signal.
  • a single remanently magnetizable thin-film of Fe88-Cr12 alloy having a thickness of 2 ⁇ m was deposited by e-beam evaporation onto a polyimide ("Kapton") film 50 ⁇ m in thickness.
  • the resulting laminate was cut into squares, each 4.2 mm on a side.
  • a pressure-sensitive adhesive transfer film 25 ⁇ m in thickness the exposed faces of the squares were bonded to the outermost Ni-Fe thin-film of the signal-producing layer in the pattern of FIG. 2 of the drawing with a spacing of 2.1 mm between adjacent squares.
  • the segmented Fe-Cr signal-blocking layer of the resulting dual-status marker was magnetized by translating it across a unidirectional magnetic field.
  • the marker When tested in an EAS system as in Example 1 while its signal-blocking layer was magnetized, the marker was passive and did not produce an alarm signal in the interrogation zone.
  • the signal-blocking layer When the signal-blocking layer was demagnetized, the magnetization state of the signal-producing layer was periodically reversed to produce an alarm signal.
  • a dual status marker was prepared as disclosed in Example 2 except as indicated.
  • a polyimide (“Kapton”) film were sequentially deposited eleven layer pairs of magnetic thin-films of Ni-Fe alloy (each 35 nm in thickness) and nonmagnetic thin-films of SiO x (each 10 nm in thickness).
  • a sample 2.5 cm square had B m 9899 G B r /B m 0.89 H c 0.55 Oe dB
  • Ni-Fe thin-film layer Onto the exposed Ni-Fe thin-film layer were deposited four layer pairs of remanently magnetizable thin-films of Fe90Cr10 (each 100 nm in thickness) and nonmagnetic thin-films of CrO x (each 10 nm in thickness applied by reactive sputtering).
  • the continuous signal-blocking layer of the resulting dual-status marker was then magnetized as in Example 1, thus preventing the marker from producing an alarm signal when exposed to the aforementioned magnetic field.
  • the dual status marker was tested in 3M's Model 3300B magnetic-type EAS system. When its signal-blocking layer was magnetized, the marker was passive and did not produce an alarm signal in the interrogation zone of the EAS system. When the signal-blocking layer was demagnetized, the magnetization state of the signal-producing layer was periodically reversed to produce an alarm signal.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)
  • Thin Magnetic Films (AREA)
EP19930403099 1992-12-23 1993-12-20 Doppelstatus-Dünnfilmmarkierung für elektronische Artikelüberwachung Expired - Lifetime EP0604293B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US99618292A 1992-12-23 1992-12-23
US996182 2001-11-28

Publications (2)

Publication Number Publication Date
EP0604293A1 true EP0604293A1 (de) 1994-06-29
EP0604293B1 EP0604293B1 (de) 2000-06-07

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EP19930403099 Expired - Lifetime EP0604293B1 (de) 1992-12-23 1993-12-20 Doppelstatus-Dünnfilmmarkierung für elektronische Artikelüberwachung

Country Status (6)

Country Link
EP (1) EP0604293B1 (de)
JP (1) JPH06231376A (de)
AU (1) AU669014B2 (de)
CA (1) CA2109643C (de)
DE (1) DE69328819T2 (de)
ES (1) ES2148211T3 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997026564A1 (en) * 1996-01-19 1997-07-24 Minnesota Mining And Manufacturing Company Electronic article surveillance markers for direct application to optically recorded media
EP0793242A1 (de) * 1996-02-28 1997-09-03 Unitika Ltd. Magnetisches Element und dessen Herstellungsverfahren
EP0782013A3 (de) * 1995-12-27 1998-08-12 Unitika Ltd. Magnetisches Markierungselement
EP0782014A3 (de) * 1995-12-27 1998-08-12 Unitika Ltd. Magnetisches Element
WO2002093523A1 (fr) * 2001-05-08 2002-11-21 Nhk Spring Co., Ltd. Produit moule en resine synthetique

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0295028A1 (de) * 1987-06-08 1988-12-14 Esselte Meto International GmbH Magnetische Vorrichtungen
WO1990007784A1 (en) * 1989-01-09 1990-07-12 Scientific Generics Limited Magnetic materials for security applications
EP0459722A1 (de) * 1990-06-01 1991-12-04 Minnesota Mining And Manufacturing Company Dünnfilm-Vielschicht-Markierungsetikett für die Warenüberwachung

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5368948A (en) * 1989-01-09 1994-11-29 Esselte Meto International Produktions Magnetic materials for security applications
US5015993A (en) * 1989-06-29 1991-05-14 Pitney Bowes Inc. Ferromagnetic alloys with high nickel content and high permeability

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0295028A1 (de) * 1987-06-08 1988-12-14 Esselte Meto International GmbH Magnetische Vorrichtungen
WO1990007784A1 (en) * 1989-01-09 1990-07-12 Scientific Generics Limited Magnetic materials for security applications
EP0459722A1 (de) * 1990-06-01 1991-12-04 Minnesota Mining And Manufacturing Company Dünnfilm-Vielschicht-Markierungsetikett für die Warenüberwachung

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0782013A3 (de) * 1995-12-27 1998-08-12 Unitika Ltd. Magnetisches Markierungselement
EP0782014A3 (de) * 1995-12-27 1998-08-12 Unitika Ltd. Magnetisches Element
WO1997026564A1 (en) * 1996-01-19 1997-07-24 Minnesota Mining And Manufacturing Company Electronic article surveillance markers for direct application to optically recorded media
US5699047A (en) * 1996-01-19 1997-12-16 Minnesota Mining And Manufacturing Co. Electronic article surveillance markers for direct application to optically recorded media
US5825292A (en) * 1996-01-19 1998-10-20 Minnesota Mining And Manufacturing Company Electronic article surveillance markers for direct application to optically recorded media
US5939985A (en) * 1996-01-19 1999-08-17 Innovative Properties Company Electronic article surveillance markers for direct application to optically recorded media
AU709228B2 (en) * 1996-01-19 1999-08-26 3M Company Electronic article surveillance markers for direct application to optically recorded media
US6097291A (en) * 1996-01-19 2000-08-01 3M Innovative Properties Company Electronic article surveillance markers for direct application to optically recorded media
EP1186911A1 (de) * 1996-01-19 2002-03-13 Minnesota Mining And Manufacturing Company Elektronische Artikelüberwachungsetiketten für optisch aufgezeichnete Medien
EP0793242A1 (de) * 1996-02-28 1997-09-03 Unitika Ltd. Magnetisches Element und dessen Herstellungsverfahren
US5932310A (en) * 1996-02-28 1999-08-03 Unitika Ltd. Magnetic element and process for producing the same
WO2002093523A1 (fr) * 2001-05-08 2002-11-21 Nhk Spring Co., Ltd. Produit moule en resine synthetique

Also Published As

Publication number Publication date
DE69328819T2 (de) 2000-12-28
EP0604293B1 (de) 2000-06-07
CA2109643C (en) 2002-03-26
CA2109643A1 (en) 1994-06-24
JPH06231376A (ja) 1994-08-19
DE69328819D1 (de) 2000-07-13
AU5180793A (en) 1994-07-07
ES2148211T3 (es) 2000-10-16
AU669014B2 (en) 1996-05-23

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