MXPA00001243A - Constituting security elements with optical diffraction effect, and device for controlling such elements - Google Patents

Abstract

The invention concerns the constitution of security elements with optical diffraction effect, and a device for controlling such elements. The use of holograms and other security elements with optical diffraction effect for protecting documents and other valuable papers, as well as bank notesagainst forgery is becoming more and more frequent presently. The element with optical diffraction effect comprises a discontinuous metal coating and/or partial metal coats and/or metal coat zones in different planes, representing an electric data coding, corresponding to the objective. The device comprises a scanner with capacitive functioning. Said scanner consists of a plurality of emitting electrodes placed side by side and a receiving electrode extending parallel to said emitting electrodes arrangement.

Description

CONSTRUCTION OF EFFECTIVE OPTICAL SECURITY ELEMENTS AND A DEVICE TO PROVE SUCH ELEMENTS DESCRIPTION OF THE INVENTION This invention relates to the construction of respective optical diffraction safety elements and to a device for testing such elements. To date, documents with effective optical diffraction security elements, in particular holograms, have been tested with expensive optical test equipment. In these procedures, the objective to be tested must be placed accurately. All the test processes are so long that these test procedures can not be used in high-speed processing machines. The test, for example, of documents with so-called optically variable devices (OVD) in a document processing machine is impossible, because they run at high speed. U.S. Patent 4,255,652, for example, discloses a device for detecting and identifying features in documents with electrically conductive regions. By means of a first capacitive element which extends over the width of the document to be tested and which is placed above this document, a load is transferred to one of the regions electrically conductive When the document to be tested is transferred, the electrically conductive charged region is placed under a second capacitive element that extends over the width of the document to be tested and the load is dissipated through this second element. A decoding evaluation circuit generates a typical signal function. This device, and the working principle used, are based on relatively large electrically conductive regions that extend over the width of the document to be tested, as the amount of load transferred decreases sharply in smaller areas. It is not possible a simultaneous test of several conductive regions nor the determination of their geometric shapes and sizes, in particular of a fine design. In addition, EP 0 097 570 proposes a device for the verification of the dielectric properties of sheet-like materials in which the material to be tested is passed through pairs of plates of a row of capacitors having a defined configuration. A change in the dielectric properties results in a change in the voltage of the receiving electrodes. The signals are amplified and processed separately. In this device, which is based on the test of the dielectric properties of the sheet material, in particular watermarks, all the capacitors are supplied simultaneously with the oscillating frequency which can cause a coupling between adjacent channels. If a larger distance between the capacitors is selected to avoid this disadvantage, the affordable geometric resolution is reduced. Therefore, only coarse structures can be detected. To eliminate transient problems on the receiver plates of the capacitors, only a relatively low frequency change is allowed, limiting the test at low speeds. Such a device can not be used in high-speed processing machines for construction reasons either. EP 0 338 378 discloses a combined process for printing and shaping a hologram, the reflective material being applied either to the hologram only or both to the hologram and to the surrounding material. The material outside the hologram is removed by etching or damage to the substrate is avoided, and it is left on the substrate. DE 27 47 156 describes a method and device for testing falsification of holographically protected identity cards. The OVD is produced and a visual verification is carried out. This method is not suitable for high-speed and efficient tests, independent of the person. A device to generate scanning patterns which are tested by means of a common mirror laser or a* giÉá¡gg ^? ^ lens system as well as a photodetector, is described in EP 0 042 946. The economic cost in this case too is very high. This is further increased if these objects are going to be tested without prior classification. To avoid pre-classification, the counterfeit test system must be tested several times. Furthermore, it is known that the demetalisations of the effective optical diffraction safety elements which until now have been tested only by means of optical methods. As is known from documents US 5,248544 and US 5,388,862, optically variable security elements for documents in the form of what are called holograms and security chains have metal films, metal films in holograms serve to generate reflections and establish a security chain that seems opaque when viewed by transmitted light. The superposition of metallized and demetallized regions in a beam and a meander pattern make the observer differentiable by the light transmitted outside the base of brightness patterns. An object of the invention is to eliminate the disadvantages of the prior art and to propose a construction of optically effective security elements by diffraction, in particular OVD, holograms or cinegrams, which can be tested quickly, independently of people and which are cheap. Another object of the invention is to propose a device for testing documents containing such elements of security. The device is designed for use in document processing machines as well as manual test units for testing documents with optically effective security elements by diffraction. 5 This problem is solved by the following description of the invention. The holograms and other security elements optically effective by diffraction for the protection of certificates and other security documents as well as checks of bank to prevent counterfeiting, now they are used more and more widely. Such documents are, for example, the DEM bank checks issued in 1997 which have an optically effective security element by diffraction in the form of a cinegram in addition to the security strip electrically driver. The rapid test capability is another stage of safety in the evaluation of optically effective safety elements by diffraction as a feature of authenticity. The optically effective safety elements by diffraction are constituted by a metallic layer, between other things. This metallization layer is electrically conductive. Changes in electrical conductivity with the thickness of the layer. According to the invention, the optically effective diffraction safety elements have a discontinuous metallization layer and / or layers and / or partially areas. metallic, metallic layers in different planes with the which represent coding of desired electrical information. The coding form recalls geometric figures, in particular lines, grid grids, arcs and / or circles, which are placed both regularly and irregularly. A partially metallic layer 5 placed on the top of a substrate includes several demetallized segments. A discontinuous metallization layer includes segments of different electrical conductivity. The device comprises an explorer that works capacitive way. This scanner is made up of a large number of transmitting electrodes placed side by side and a receiving electrode that runs parallel to this side-by-side arrangement. The scanner is placed in a document processing machine in such a way that the optical or mechanical sensors provided in the usual document processing machines activate the test device according to the invention. To avoid detection and measurement errors, preferably a sensor carrier is used. This sensor carrier accommodates all the sensors required for the test.

This allows the distances between the sensors to be minimized and the sensors always to be placed in defined positions. The activation of the individual transmitting electrodes by electrical energy is alternated by means of an electronic activation system with a change on the frequency in the range of kHz. In addition to the unit energy supply, the electronic activation system comprises as main components a multiplexer, an oscillator for the supply of energy to the transmitting electrodes and an oscillator for the activation of the multiplexer. The energy of the respective activated transmitting electrodes is capacitively overlapped if there is electrical conductivity at the transmitting electrode and the receiver. If there is no electrically conductive feature, no energy will be transferred between the activated transmitting electrode and the receiving electrode. The signal response at the receiving electrode is converted to a relevant signal image. The signal image depends on the structure of the metallized layer of the optically effective element by diffraction. If the optically effective elements by diffraction have a discontinuous metallization layer, several segments of the metallization layer have different electrical conductivities. An electronic evaluation system downstream for the receiving electrode compares the image of the test object signal with the relevant reference signals. The electronic evaluation system consists mainly of a power supply unit, an amplifier, a demodulator, a comparator, a microprocessor with memory as well as filters for the suppression of external and interference signals.

- MUlStttßM &lWW * • "• ^^ - ^^ - y ~ ^ j In addition to the software for the microprocessor, the reference signal images for comparison with the sampled signal image of the test document are stored in a memory. As the scanner exceeds the total width of the document, the device according to the invention detects each electrically conductive characteristic.The comparison with the reference signal images provides a classification signal for reprocessing.Therefore, a document detected as falsified , for example, it can be separated by classification when stopping the test device. To reduce the effects of interference, the sensor carrier is firmly connected to the mounting plate that supports the electronic activation and evaluation systems. The entire test device is placed inside the document processing machine so that the space required is relatively small. The transmitter and receiver electrodes are placed above or below the documents in the document processing machine in such a way that a scan is ensured reliable. This is done, for example, by means of tapes or in the area of reversing devices so that the document during transport is pressed against the transmitting and receiving electrodes. In a modified arrangement of the electrodes without altering the scope of the invention, an electrode is placed stretched transmitter long parallel to a side-by-side arrangement of a large number of receiving electrodes. In this case, the received signals are processed by means of a multiplexer. The rest of the electronic evaluation system is the same as described above. In another embodiment of the transmitting and receiving electrodes, a large number of transmitting and receiving electrodes are placed side by side and / or in a row. For both signals, both activation and reception, the multiplexing or demultiplexing. If the test device is to be used in manual units, the manual units comprise two devices suitable for transporting the document or the scanner which works similar to the transport devices in copiers., optical image feed scanners or fax machines. As a modification, a device can be provided which defines the position of a working scanner capacitively of the test device, according to the invention to the document by means of stop elements. In this case, the document is tested only in the area of the transmission and reception electrodes. The characteristics of the invention will appear from the descriptions and the drawings in addition to the claims, the individual characteristics as well as the ^^ £ át¿¿A f < - »^^ t- 'individual aspects or several aspects in the form of sub-combinations representing advantageous patentable modalities for which protection is requested here. The invention will be explained in more detail below, with reference to the modalities thereof which are represented in the accompanying drawings, in which: Figure 1 is a schematic diagram of a document with an OVD with demetallised layers similar to meanders; Figure 2 is a schematic diagram of a document 10 with an OVD, with demetallised layers similar to strips; Figure 3 is a schematic diagram of a document with an OVD with strip-like demetallised layers; Figure 4 is a schematic diagram of a document with an OVD with demetalized grid-like layers; Figure 5 is a schematic diagram of a document with an OVD with various security elements; Figure 6 is a block diagram of a test device; Figure 7 is a schematic diagram of a scanner with a large amount of transmitting electrodes and a receiving electrode; Figure 8 is a schematic diagram of the scanner with a transmission electrode and a large number of receiving electrodes; - Figure 9 is a schematic diagram of the scanner with a large number of transmitting and receiving electrodes; Figure 10 is a schematic diagram in a side view of the scanner and a document to be tested. Figure 11 is a schematic section through a OVD with demetallized segments; Figure 12 is a voltage-time diagram of the evaluation signal; Figure 13 is a schematic section through an OVD with a discontinuous metallization layer; Figure 14 is a voltage-time diagram of the evaluation signal. Each of the embodiments shown in figures 1 to 5 presents a document with security elements according to the invention each of which contains a proposed electrical coding. In the coding process, any information is not simply coded but electrically conductive structures are placed towards or between each other, separated by non-conductive structures, to obtain electrically conductive test characteristics whose electrical coding occurs through the test device of the invention a predetermined signal response which is compared to an existing stored reference signal response. By this procedure, a high test speed is obtained, which is desired. The browser The work capacitively of the device according to the invention is also represented schematically. Figure 1 shows the schematic structure of an OVD 1 with a metallization layer 2. The metallization layer 2 has a demetallised zone 3. Viewed from the top, demetallised zone 3 has the shape of a meander. The width of the demetallized zone 3 in the shape of a meander is larger than the smallest distance between two electrodes. The capacitively operating scanner 4 is constituted by a large number of transmitting electrodes 5 placed side by side and a receiving electrode 6 placed parallel to this side-by-side arrangement. Figure 2 shows the schematic structure of an OVD with strip-like zones 7, metallized, and strip-like, demetallized zones 8 which are placed alternately parallel to each other. The zones 7, 8 are in the form of strips when viewed from the top that runs parallel or perpendicular to the transport direction of the document. The latter case is shown in figure 3. The distance between two zones of equal electrical conductivity varies from 0.2 to 1.0 mm. The width of the electric conductivity zones varies. Figure 4 shows a combination of the characteristics of modes 2 and 3. Parallel to the direction of document transport, zones 7 similar to The metallic strips and the zones 8 similar to demetallised strips are placed alternately. The metallized zones 7 are interrupted by a demetallised zone 9, similar to strip running perpendicular to them. Figure 5 shows a document with several OVDs. The desired combination of optically effective security elements by diffraction produces another coding. This increases the reliability of the test. Figures 6 to 9 show in block diagram as well as different modalities of the explorer 4 working capacitively. Figure 6 shows the block diagram of the test device according to the invention, which comprises an electronic activation system, a working explorer 4 capacitively and an electronic evaluation system. In addition to the power supply unit, the electronic activation system is mainly composed of a demultiplexer 10, an oscillator 11 for supplying power to the transmitting electrodes, and an oscillator 12 for activating the demultiplexer. The electronic evaluation system consists mainly of a power supply unit, an amplifier 13, a demodulator 14, a comparator 15, a microprocessor 16 with memory as well as filters for the suppression of external and interference signals.

The transmitter and receiver electrodes are embedded in a sensor carrier. The electrodes form an explorer 4 working capacitively over the entire width of the document feed. The strip-like receiving electrode 5 runs transversely to the feeding direction of the document. The transmitting electrodes are placed parallel to the receiving electrode. The distance between the transmitting electrode and the receiving electrode is determined by the electrically conductive test characteristics, specific of the document. The provision side by side of several transmitting electrodes allows several electrically conductive characteristics to be detected simultaneously along the longitudinal axis of the explorer 4 which works capacitively, the resolution that can be obtained with this arrangement depends of the number of transmitting electrodes used. In this modality, the resolution is a point explorable by millimeter in both longitudinal and transverse directions. The minimum distance between adjacent transmitting electrodes is limited by the capacitive interference coupling between yes. To avoid this and reduce the interference effects of adjacent transmitter-electrodes, the transmitting electrodes are activated successively by a multiplexer 10. The arrangement of the transmitting electrodes over the entire width of the document feed allows the documents to be try regardless of your position. This means that already ; ^ »4t¿tf ... -». »V. - « "« < * 3 > .a j, - »..: ^,«,., .f ^^. V.B », ... -» - «a. no more prequalification of several documents is required for a document processing machine. Figure 7 shows the schematic diagram of the scanner 4 with a large number of transmitting electrodes 5 and a receiving electrode 6. The activation and evaluation are in accordance with the block diagram shown in Figure 6. Figure 8 shows a schematic diagram of a mode of the working scanner 4 operating capacitively with a transmitting electrode 17 and a large number of electrodes 18 receivers. As a modification of the block diagram of Figure 6, the transmitting electrode 17 is activated by means of an oscillator. The signals of the receiver electrodes 18 are processed by means of a multiplexer. The rest of the electronic evaluation system comprises a power supply unit, an amplifier, a demodulator, a comparator, a microprocessor with memory as well as filters for the suppression of external and interface signals reminiscent of those of the block diagram shows in figure 6. Figure 9 shows the schematic diagram of another mode of the explorer working capacitively with a large number of transmitting electrodes 19 and a large number of receiving electrodes 20. These are placed alternately in a row. Thus, both the activation signals of the transmitting electrodes 19 and the evaluation signals of the receiving electrodes 20 are processed by the multiplexing or demultiplexing method. Figure 10 shows a side view of a schematic diagram of the explorer 4 working capacitively and a document to be tested. The OVD includes partial metallizations 21 as well as a film 22 that carries electrically insulating. Figure 11 shows a schematic section through an OVD with a substrate 23 and a layer 24 partially metal. The partially metallic layer 24 includes several demetallised segments. The relevant evaluation signal is shown in a voltage-time diagram in Figure 12. Figure 13 shows a schematic section through an OVD with a substrate 26 and a discontinuous metallization layer 27. The discontinuous metallization layer 27 includes segments 28, 29, 30, 31, 32 with different electrical conductivity. The relevant evaluation signal is shown in a voltage-time diagram in Figure 14. In the present invention, the construction of optically effective safety elements 20 by diffraction and a device for testing such elements is explained with reference to the embodiments of the invention. same. It should be understood, however, that the present invention is not limited to the details of the description in the embodiments, since the alterations and modifications as claimed are within of the scope of the patent claims. In addition to the optically effective safety element by diffraction, other electrically conductive characteristics are detected with the device according to the invention. The proposed combination of optically effective security elements by diffraction, with other electrically conductive characteristics results in another coding. In addition, other electrically conductive test characteristics, such as electrically conductive electrically conductive paint strips or encodings, can be classified by means of the test device according to the invention.

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Claims (23)

1. A construction of optically effective security elements by diffraction in documents in which the optically effective diffraction security element is provided with a directed electrical coding of information comprising a discontinuous metallization layer and / or partially conductive metallic layers.

2. The construction as described in claim 1, wherein the optically effective diffraction safety element is provided with directed electrical coding of information comprising a discontinuous metallization layer and / or partially conductive metal layers and metal layer zones in different blueprints.

3. The construction as described in claim 1 or 2, wherein the coding form recalls geometric figures, in particular lines, mesh lines, arcs and / or circles.

4. The construction as described in claim 1 or 2, in which the coding form recalls the regularity of irregularly arranged geometric figures, in particular lines, mesh lines, arcs and / or circles.

5. The construction as described in claim 1 or 2, wherein the demetallized zone has the shape of a meander when viewed from the top.

6. The construction as described in claim 1 or 2, wherein the zones similar to metallized strips and zones similar to demetallized strips are placed alternately parallel to each other, the strip-like zones run parallel or perpendicular to the transport direction of the document when it is observed from the top.

7. The construction as described in claim 1 or 2, wherein the distance between the two zones of equal or different electrical conductivity corresponds to the shortest distance between the two electrodes.

8. The construction as described in claim 7, wherein the distance between two zones of equal or different electrical conductivity is at least 0.1 mm.

9. The construction as described in one or more of the preceding claims, in which the metallized zones are interrupted by one or more demetallised zones running perpendicular to the zones 5 metallized.

10. The construction as described in one or more of the preceding claims, wherein the optically effective diffraction safety element is a device 10 optically variable.

11. The construction as described in one or more of the preceding claims, wherein the element is optically effective by diffraction is a hologram.

12. The construction as described in one or more of the preceding claims, wherein the optically effective diffraction safety element is a cinegram.

13. A device for testing documents with optically effective security elements by diffraction with a metallic reflection layer, as described in claims 1 to 12, comprising a capacitively working scanner whose width exceeds the largest width of the 25 document, which includes a side-by-side provision of a large number of electrodes, an electronic activation system and an electronic evaluation system for comparing the signal response of the document to be tested with the relevant reference signal responses.

14. The device as described in claim 13, in which a large number of electrodes are connected side by side and / or in several rows, a receiving electrode or a transmitting electrode extends parallel to a 10 large number of transmitting electrodes placed side by side or a large number of receiving electrodes placed side by side.

15. The device as described in claim 13, wherein the electronic activation system comprises a power supply unit, a multiplexer, an oscillator for supplying power to the transmitting electrodes and an oscillator for activating the multiplexer.

16. The device as described in claim 13, wherein the electronic evaluation system comprises a power supply unit, an amplifier, a demodulator, a comparator, a microprocessor with memory as well as filters for the suppression of external signals and interference.

17. The device as described in one or more of claims 13 to 16, wherein the smallest distance between the electrodes is less than 0.5 mm.

18. The device as described in one or more of claims 13 to 17, wherein the distance between a 10 transmitting electrode and the receiving electrode is at least 0.5 mm.

19. The device as described in one or more of claims 13 to 18, wherein the device is 15 placed in high-speed document processing machines.

20. The device as described in one or more of claims 13 to 19, wherein the device is 20 placed in manual units.

21. The device as described in one or more of claims 13 to 20, wherein the device is placed in document reading units. 25

22. The device as described in one or more of claims 13 to 21, wherein the scanner is placed over the entire width of the document in such a way that the optically effective security elements by diffraction in one and in the same document which They are different in appearance but having the same electrical properties are compared by means of a microprocessor.

23. The device as described in one or more of claims 13 to 23, wherein the scanner is placed over the entire width of the document in such a way that the optically effective security elements by diffraction in one and the same document which has the same appearance but different electrical properties are compared by means of a microprocessor. ^ - aai & ^ - ^ É ^ = ^ .. ^. ^ * ^ .¿ssfc ^ *. _? SUMMARY OF THE INVENTION The invention relates to the construction of optically effective security elements by diffraction and a device for testing such elements. Holograms and other optically effective security elements by diffraction for the protection of certificates and other security documents as well as banknotes against counterfeiting are now used more and more widely. According to the invention, The optically effective element by diffraction has a discontinuous metallization layer and / or partially metallic layers and / or areas of different flat metal layers which provide a desired electrical information coding. The device includes an explorer that works 15 capacitively. The scanner comprises a large number of transmitting electrodes placed side by side and a receiving electrode running parallel to this side-by-side arrangement. The scanner is placed in a document processing machine in such a way that the optical and mechanical sensors 20 which are provided in the usual document-processing machines activate the test device according to the invention. The energy of the respective activated transmitting electrode is capacitively over-coupled if there is electrical conductivity between this transmitting electrode and the 25 receiving electrode. If there is no characteristic electrically conductive, the energy will be transferred between the activated transmitter electrode and the receiving electrode. The signal response at the receiving electrode becomes a relevant signal image. The signal image depends on the structure of the metallized layer of the optically effective element by diffraction. An electronic evaluation system downstream of the receiving electrode compares the signal image of the test object with the relevant reference signals.