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WO1997039429A1 - Procede et dispositif d'authentification d'une feuille dans laquelle on a incorpore un fil de securite - Google Patents

Procede et dispositif d'authentification d'une feuille dans laquelle on a incorpore un fil de securite Download PDF

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Publication number
WO1997039429A1
WO1997039429A1 PCT/NO1997/000104 NO9700104W WO9739429A1 WO 1997039429 A1 WO1997039429 A1 WO 1997039429A1 NO 9700104 W NO9700104 W NO 9700104W WO 9739429 A1 WO9739429 A1 WO 9739429A1
Authority
WO
WIPO (PCT)
Prior art keywords
sheet
sensor
security thread
electrode
electrodes
Prior art date
Application number
PCT/NO1997/000104
Other languages
English (en)
Inventor
Einar Gotaas
Original Assignee
Einar Gotaas
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Einar Gotaas filed Critical Einar Gotaas
Publication of WO1997039429A1 publication Critical patent/WO1997039429A1/fr

Links

Classifications

    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/02—Testing electrical properties of the materials thereof
    • G07D7/026—Testing electrical properties of the materials thereof using capacitive sensors

Definitions

  • the invention relates to recognition and approval or disapproval of a security thread in a dielectric sheet, particularly a bank note or a document.
  • the security thread used today in bank notes and security paper is most often a metal thread or a metallized thread of plastics.
  • the plain plastics threads used as security threads are no longer in use in European bank notes and documents.
  • a metal thread or a metallized plastics thread will, such as described in this invention, exhibit quite special electrical properties.
  • the invention can easily distinguish a "genuine" security thread from copies made by means of printing methods, as well as copies/forgeries made by means of tape, plastics etc.
  • In the market today there are numerous different methods for rapidly, cheaply and simply providing a good indication as to whether a bank note is genuine or counterfeit. However, most methods turn out to be too time- consuming, require training, have a large uncertainty, or to be too costly.
  • the invention is based upon the fact that in most genuine bank notes, there is a metal thread or a metallized thread. This thread is very difficult to "insert" in the paper before a counterfeit bank note is printed.
  • the security thread lies embedded, partly in the center of the note paper. Further, it is difficult to find a suitable material for use in such forgeries.
  • the genuineness detector will distinguish between various thread types. This can of course in itself be used as a security criterium.
  • counterfeiter manages to embed a genuine security thread, he will also probably use better printing techniques than a copying machine. In reality, one is then facing a professional, skilled and qualified counterfeiter. Such a person must be stopped with the aid of quite different methods.
  • the present invention substantially uses the same measurement principle as mentioned regarding DE 43 39 417, but utilizes a technique which provides better defined signals, thereby providing an increased possibility for being able to distinguish rapidly between genuine and false bank notes.
  • a genuineness sensor is achieved which is quite useful in practice, can be manufactured at a correct price, and not least has a reliability which is very good.
  • a method and an apparatus are provided for authentication of a dielectric sheet having a security thread embedded therein, the method and the apparatus including the features disclosed in the appended independent patent claims 1 and 4.
  • Advantageous embodiments of the invention appear from the dependent patent claims 2, 3 and 4-7 attached to the indepen ⁇ dent claims.
  • fig. 1 shows part of a paper note having a genuine security thread
  • fig. 2 shows the upper part of a sensor
  • fig. 3 shows the lower part of a sensor
  • fig. 3b shows a bank note passing the sensor
  • fig. 4 shows the upper and lower parts of the sensor mounted together
  • fig. 5 shows an example of a simple electrical signal processing circuit
  • fig. 6 shows a form of the output signal from part of the signal processing circuit of fig. 4
  • fig. 7 shows a bank note having two security threads, as well as one side of a sensor
  • fig. 7b shows a bank note having a double thread, as well as one side of the sensor.
  • Fig. 1 shows part of a paper note 1 having a security thread 2.
  • Fig. 2 shows one side of the sensor through which the paper note is to be passed.
  • 3 is an insulating material
  • 4 is a metal contact, about 2 x 2 mm
  • 5 is a metal contact about 5 x 5 mm.
  • Fig. 3 shows the other side of the sensor though which the paper note is to be guided.
  • 7 is a metal contact, about 2 x 2 mm, provided in alignment with the corresponding contact 4 in fig. 2.
  • 8 is a metal contact, about 5 x 5 mm, provided in alignment with the opposite and corresponding contact 5 in fig. 2.
  • Fig. 4 shows the sensor in an assembled state.
  • the two sides of the sensor (3 and 6) are placed at a distance d from each other, (d will typically be about 0,2 - 0,5 mm).
  • the metal electrodes 7 and 8 are spring-loaded, via the device 11a and 11b, so that the metal electrodes 7 and 4 "are pressed together" via 11a. Similarly for electrodes 8 and 5, via the device 11b.
  • the paper note to be tested is guided in between plates 3 and 6 as indicated in fig. 3b.
  • the bank notes must be pulled through the sensor, so that during a short moment the security thread will pass the small electrode pair 7 and 4, at the same time as the thread is also covered by the somewhat larger electrode pair 5 and 8.
  • the electrode 4 has a connecting lead 9a
  • the electrode 5 has a connecting lead 10a
  • the electrode 7 has a connecting lead 9b
  • electrode 8 has a connecting lead 10b.
  • 9a and 9b are connected together, and 10a and 10b are connected together.
  • Fig. 3b shows a bank note, including a security thread, which is placed in the sensor, a small section of the security thread being covered by electrode pair 7 and 4, and at the same time the thread is also covered by the somewhat larger electrode pair 5 and 8.
  • Fig. 5 shows a simple electrical circuit for demonstrating a genuine thread.
  • An oscillator O generates an AC voltage, designated U (0,1-1 MHz). This voltage is connected, via 9a, 9b, to one electrode pair, in the drawing figure denoted E.
  • the other electrode pair, denoted D is connected, via 10a, 10b, to amplifier A.
  • the output signal from A is designated U s ⁇ .
  • the security thread in the bank note is most often completely covered by bulk paper. From the electrode pair in E, there will be a capacitive coupling of the AC voltage into the security thread. This connecting capacitance is drawn in the figure as C1.
  • the size of the electrodes can in principle be selected relatively freely.
  • the inventive idea is that a genuine security thread will conduct an electrical signal across the bank note. (There are genuine security threads made merely from plastics material. Such a thread will not be easily detected in this invention.) However, per se previously known techniques with shape-adapted electrodes, will also be able to increase the quality of the genuineness detection somewhat in this invention.
  • the electrode pair D has a size about the same as the width of the security thread (2 x 2 mm).
  • the electrode may well be given a rectangular shape, so that the coupling capacitance from the thread into the electrodes is as large as possible.
  • the electrodes may be "thread shaped" , for instance 1 x 20 mm. This would result in a large coupling signal, but the geometry would also be very sensitive to how the bank note is guided through the sensor. If the electrodes are long and narrow, and the note thread is not passed through the sensor with such an angle that optimum adaptation occurs, the sensor will give a reduced performance.
  • one electrode is prepared to "match" the thread, being long and narrow, e.g. 1 x 20 mm, it is important that the other electrode, E, should be significantly larger. This in order to ensure that the electrodes cover the thread in an optimum manner.
  • Fig. 6 shows a signal observed in an oscilloscope
  • U is the voltage from the oscillator
  • Ust is the signal when a thread is located "correctly" in the sensor
  • Uo is the signal when there is no security thread in the paper.
  • the ratio of Ust to Uo is quite large for most types of security thread, e.g.
  • curve Ust provides good information regarding the properties of the thread that is tested.
  • Electrode 7 (electrode pair 7 and 4) is now prepared as two somewhat elongate electrodes. Each one of the electrodes has the same width as the bank note thread. The distance between the electrodes is made equal to the distance between the threads. This double electrode may very well be connected together to provide one common electrode.
  • Fig. 7b shows the position of the bank note which results in the maximum coupling in position D (fig. 5), and thereby the largest signal output from the electrical signal processing circuit.
  • the material of which the bank note is made in principle may be any non-conductive material.
  • the invention may very well be used to detect electrically conductive materials inside e.g. a plastic foil.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Inspection Of Paper Currency And Valuable Securities (AREA)
  • Credit Cards Or The Like (AREA)

Abstract

On décrit un capteur destiné à authentifier un billet de banque en fonction de la détection d'un fil métallique de sécurité, incorporé dans ce billet. Des paires d'électrodes assurent un couplage d'entrée et, éventuellement, un couplage de sortie d'un signal électrique en courant alternatif, transmis entre les paires d'électrodes, pendant la courte durée du passage, devant celles-ci, d'un fil de sécurité inséré dans un billet de banque. L'agencement des électrodes en paires, c'est-à-dire une électrode d'une paire placée de chaque côté de la fente à travers laquelle on fait passer le billet de banque, assure un bon couplage d'entrée et de sortie du signal électrique.
PCT/NO1997/000104 1996-04-18 1997-04-18 Procede et dispositif d'authentification d'une feuille dans laquelle on a incorpore un fil de securite WO1997039429A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO961527A NO961527L (no) 1996-04-18 1996-04-18 Fremgangsmåte og apparat for autentisering av et ark med innleiret sikkerhetstråd
NO961527 1996-04-18

Publications (1)

Publication Number Publication Date
WO1997039429A1 true WO1997039429A1 (fr) 1997-10-23

Family

ID=19899270

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO1997/000104 WO1997039429A1 (fr) 1996-04-18 1997-04-18 Procede et dispositif d'authentification d'une feuille dans laquelle on a incorpore un fil de securite

Country Status (2)

Country Link
NO (1) NO961527L (fr)
WO (1) WO1997039429A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4355300A (en) * 1980-02-14 1982-10-19 Coulter Systems Corporation Indicia recognition apparatus
US5394969A (en) * 1991-12-31 1995-03-07 Authentication Technologies, Inc. Capacitance-based verification device for a security thread embedded within currency paper
US5417316A (en) * 1993-03-18 1995-05-23 Authentication Technologies, Inc. Capacitive verification device for a security thread embedded within currency paper
DE4339417A1 (de) * 1993-11-18 1995-05-24 Optima Buerotechnik Gmbh Banknoten - Prüfgerät
US5419424A (en) * 1994-04-28 1995-05-30 Authentication Technologies, Inc. Currency paper security thread verification device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4355300A (en) * 1980-02-14 1982-10-19 Coulter Systems Corporation Indicia recognition apparatus
US5394969A (en) * 1991-12-31 1995-03-07 Authentication Technologies, Inc. Capacitance-based verification device for a security thread embedded within currency paper
US5417316A (en) * 1993-03-18 1995-05-23 Authentication Technologies, Inc. Capacitive verification device for a security thread embedded within currency paper
DE4339417A1 (de) * 1993-11-18 1995-05-24 Optima Buerotechnik Gmbh Banknoten - Prüfgerät
US5419424A (en) * 1994-04-28 1995-05-30 Authentication Technologies, Inc. Currency paper security thread verification device

Also Published As

Publication number Publication date
NO961527L (no) 1997-10-20
NO961527D0 (no) 1996-04-18

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