Indian Patents. 226510:SECURITY PAPER FOR PRODUCING DOCUMENTS OF VALUE, AND METHOD OF ITS PRODUCTION

Title of Invention	SECURITY PAPER FOR PRODUCING DOCUMENTS OF VALUE, AND METHOD OF ITS PRODUCTION
Abstract	The invention relates to a security paper for producing documents of value (1), such as bank notes, certificates, etc., with at least one multilayer security element (2). The security element is disposed at least partly on the surface of the security paper and has at least one visually checkable optical effect (7) and at least one integrated circuit (8).

Full Text	"SECURITY PAPER FOR PRODUCING DOCUMENTS OF VALUE, AND METHOD OF ITS PRODUCTION" This invention relates to a security paper for producing documents of value, such as bank notes, certificates, etc., with at least one multilayer security element having at least one visually checkable optical effect, the security element being disposed at least partly on the surface of the security paper. The invention further relates to a multilayer security element and to a document of value with such a security element. A transfer material for applying a multilayer security element to a document of value and a method for producing the transfer material and the document of value are also the sub- ject matter of the invention. There is a constant interest in protecting papers of value against forgery and un- authorized reproduction. It is becoming ever more difficult, particularly in view of to- day's copying and printing techniques, to find effective security features that at least make unauthorized reproduction or forgery clearly recognizable, if they do not actually prevent it. EP 0019 191 B1 proposes for example providing a paper of value with an inte- grated circuit in which a checkable coding is written, the communication with the inte- grated circuit preferably being effected contactlessly via antennas. The integrated cir- cuit is set in the gap of an at least partly metalized carrier foil. This foil is then lami- nated between two paper webs. Since the carrier foil is only laminated in between the two paper webs, however, there is the danger that the layers can be separated from each other relatively easily so that the plastic inlay provided with the chip can be used for possible forgeries. Further, this security element is a strictly machine-checkable security element that can only be checked by means of special detectors. Frequently used authenticity features that are very easily visually checked and very striking are optically variable security elements, for example holograms, that show different visual impressions, such as color effects or information, from different viewing angles. A paper of value with such a security element is known from EP 0 440 045 A2. A bank note is described here that is provided with a label-like hologram. Since the optically variable effect of the hologram cannot be rendered by a color cop- ier, these security elements offer very good protection against color copying. However, However, these security elements have the disadvantage that they are very poorly checkable by machine, since the radiation reflected by the diffraction structures of the hologram must be detected at certain solid angles and the influence of stray radiation largely excluded to permit reliable ascertainment of the presence of a certain hologram. A further problem is the fluctuating signal intensity, since the latter is greatly dependent on the illumination source of the hologram. For reliable measure- ment, defined lighting conditions must therefore be ensured. To avoid this problem, it was therefore also proposed to superimpose a visually readily visible hologram with a strictly machine-readable laser transmission hologram (DE 38 40 037 C2). Readout of the machine-readable hologram can be effected only by means of a laser, the information hidden in this laser transmission hologram being projected onto a certain space coordinate in front of the document of value that is al- ready defined when the hologram is recorded. The detector must be located at this place to permit this hidden information to be recognized. However, this type of visual and machine protection for a document of value is very elaborate both to produce and to check. The invention is therefore based on the problem of proposing a document of value and a security paper with a security element having a visually checkable optical effect and also being checkable by machine, the security paper and document of value being preferably easy and cost-effective to produce. This problem is solved by the features of the independent claims. Developments are the subject matter of the subclaims. According to the invention, "security paper" designates the unprinted paper that can have not only the inventive security element but also further authenticity features, such as luminescent substances provided in the volume, a security thread or the like. It is usually present in quasi endless form and is processed further at a later time. "Document of value" refers to a document that is finished for its intended use. It may be for example a printed paper of value, such as a bank note, certificate or the like, an ID card, a passport or another document requiring protection. The invention will be described hereinafter with reference to the security paper. However, the advantages and embodiments apply analogously to documents of value. According to the invention, the security paper is provided with at least one multi- layer security element having an optical effect that can be easily checked visually and not rendered by copying technology, or only in falsified form. This security element is disposed at least partly on the surface of the security paper and contains at least one integrated circuit in one of its inside layers. This integrated circuit is for example a strict memory chip (ROM), a rewritable chip (EPROM, EEPROM) or a microproces- sor chip. The chips used have a thickness of 5 microns to 50 microns, preferably 10 mi- crons, and an edge length of about 0.1 millimeters to 3 millimeters, preferably 0.6 mil- limeters. On the chip there are preferably two to four contact surfaces. The optical effect of the security element can be produced by a layer containing optically variable pigments, in particular interference-layer or liquid-crystal pigments. This layer can be present all over or in the form of information. Alternatively, the se- curity element can also have a hologram, kinegram or other diffraction structure. Pref- erably, the diffraction structures are embossed into a plastic layer in the form of a re- lief structure. If the diffraction structures are to be observable in reflected light, they are combined with a reflecting layer, in particular a metal layer or a dielectric layer with a high refractive index. The reflecting layer need not be provided all over, how- ever, but can be applied in the form of a screen or any other information. In particular, it can have gaps in the form of patterns or characters. A further possibility for produc- ing a visually checkable optical effect is to use thin-film structures wherein metallic and/or dielectric layers with different refractive indexes are disposed one above the other, the layers cooperating so that different visual impressions arise at different viewing angles at least when viewed in reflected light. These different visual impres- sions are preferably different color effects. Alternatively, the optical effect can also be produced by any printed image or a metallic layer with gaps in the form of patterns, characters or the like. The metal layer itself can likewise be present in the form of characters or patterns. The use of special printing inks, such as luminescent inks, is also possible. Of course, a plurality of secu- rity features producing an optical effect can also be used. When a layer producing an optical effect is spoken of below, this also refers to cooperating multilayer structures, such as the abovementioned dielectric thin-film elements or combinations of a plural- ity of layers that produce different optical effects. The term "hologram" is likewise intended to stand for any diffraction structures. The inventive integrated circuit is preferably disposed between this layer having the optical effect and the security paper. It is thus protected outwardly from environ- mental influences and practically does not appear visually. It is advantageous to use integrated circuits with which communication is effected contactlessly via a coupling element. The coupling element can already be an integrated part of the integrated cir- cuit or be disposed in a layer of the security element. Integration of the coupling ele- ment into the layer structure of the security element involves the advantage that in case of attempted manipulation or forgery the circuit cannot be separated operably from an original security element or a security paper equipped therewith, for example to be incorporated into a counterfeit reproduction. The coupling element can be a folded dipole, a coil or an open dipole. To increase the effectiveness of the system, the folded dipole or the coil can also have a metalized core zone. If the coupling element is formed on the layer producing the optical effect, the filled core zone also causes the visual impression of the layer to be less disturbingly influenced by the coupling ele- ment. The read range is between about 0.1 millimeters and a few centimeters depend- ing on the type of coupling element and the selected read/write frequency, for example 13.56 megahertz and 2 gigahertz. The inventive security element is preferably applied to the security paper after papermaking and is so connected with the security paper that it cannot be removed without destroying the security paper or the security element. The invention thus has the advantage that the security element does not have to be integrated into the paper- making process and is nevertheless connected with the paper of value in forgery-proof fashion. A further advantage is that the security element is protected against attempts at forgery in several respects. The optical effect of the layers facing the viewer cannot be rendered true to the original with copying machines or other reproduction tech- reproduction techniques, so that such attempts at forgery can already be visually recognized easily and fast. If an attempt to reproduce or imitate the optical impression of the security element should succeed, however, the forgery can nevertheless be recognized upon the machine check of the integrated circuit. Since the circuit is disposed inside the security element and covered by the layers producing the optical effect, a potential forger will not notice this additional authenticity feature and therefore not attempt to imitate it. The inventive security element is preferably formed as a multilayer self-support- ing label or as a transfer element that is connected with the security paper after its pro- duction. The contour form of the security element is freely selectable. Alternatively, the secuirity element can also be formed as a security thread. In this case, the integrated circuit and the layer producing the optical effect are disposed on a thread-shaped plas- tic substrate that is so incorporated into the paper web during papermaking that the thread passes directly to the surface of the security paper in partial areas. According to a preferred embodiment, the security thread consists of two plastic substrates between which the integrated circuit and the layer producing the optical effect are disposed. A "transfer element" refers according to the invention to a security element that is prepared on a separate carrier layer, for example a plastic foil, in the reverse order as it later comes to lie on the security paper, and then transferred to the security paper by means of an adhesive or lacquer layer in the desired contour forms. The carrier layer can be removed from the layer structure of the security element after transfer, or re- main a firm part of the security element on the layer structure as a protective layer. The individual transfer elements can be prepared on the carrier layer as separate individual elements in the contour forms to be transferred. Alternatively, the layer se- quence of the transfer elements is provided on the carrier layer in continuous form. Such carrier layers with spaced-apart individual transfer elements or a continuously extending layer structure will hereinafter be referred to as "transfer material," and the layer sequence of the security element disposed on the carrier layer as the "transfer layer." In the case of the continuous transfer layer, the transfer material is then con- nected with the security paper via an adhesive layer, and the adhesive layer activated via suitable embossing tools so that the transfer layer adheres to the security paper only in the activated areas. All other areas are then removed with the carrier layer. Al- ternatively, the adhesive layer can also be executed in the form of the security element to be transferred. Adhesives preferably used are hot-melt adhesives. However, any other adhesives, such as reaction lacquers, can also be used. The security element can alternatively be applied to the document of value. The embodiments and fastening possibilities described in connection with the security pa- per apply analogously in this case. Hereinafter, some preferred layer sequences of the inventive security element will be explained in more detail by the example of the transfer material. The analogous layer sequence, only in the accordingly reverse order of layers, can of course also be used for labels and security threads. In the simplest form, the transfer material consists of a carrier layer, in particular a transparent plastic foil, at least one layer producing the optical effect and at least one integrated circuit. In this embodiment the integrated circuit also contains the coupling element for communication with a read/write device. If an integrated circuit not having an integrated coupling element is used, a suit- able coupling element must be provided in the layer structure of the transfer layer of the transfer material. The transfer layer with the integrated coupling element is then preferably formed as a thin, non-self-supporting foil. This thwarts attempts at forgery that aim at detaching the original security element from a security paper, since the non-self-supporting security element is not removable without being damaged. This coupling element can be an open dipole, a folded dipole or a coil. This cou- pling element is preferably produced by suitable demetalizings in a metal layer. For this purpose the carrier layer of the transfer material, which is optionally provided with a separation layer, is provided with the layer producing the optical effect. On this layer layer a water-soluble or other layer soluble by means of a solvent is then printed in the form of the areas to be demetalized. In the next step, the carrier layer is metalized com- pletely on the printed side. In a last step, the soluble ink and the metalization present in these areas are removed. The integrated circuit is fastened to this layer by means of a conductive adhesive layer, for example conductive silver or an anisotropic conductive adhesive. Finally, the carrier layer is provided with an adhesive layer at least in certain areas. Alternatively, the structuring of the metal layer can also be effected by means of known etching techniques. In this connection, the carrier layer is provided directly with the all-over metalization after application of the layer producing the optical ef- fect. The metal layer is then printed with a protective lacquer layer in the form of the desired coupling element. The non-covered areas are then removed with suitable sol- vents. The protective layer can also be produced by photographic means by coating the metal layer all over with a photoresist that is then exposed and developed. According to a variant, the metallic layer forming the coupling element can be separated from the layer producing the optical effect by an insulating layer. This is necessary in particular when the layer producing the optical effect likewise has a con- ductive layer. According to a further embodiment of the invention, however, it is also possible that the metallic layer is at the same time required for the visually optical effect. If a reflection hologram is used for example, the layer producing the optical effect usually consists of an embossed lacquer layer in which the diffraction structures of the holo- gram are embossed in the form of a relief structure, and a metal layer. The carrier layer of the transfer material is first provided with the embossed lacquer layer in which the diffraction structures are embossed. This lacquer layer is then provided with a metal layer. Before the metal layer is preferably vapor-deposited, however, a soluble ink is printed on for producing the coupling element, as explained above. After metalization, the soluble ink is removed and the integrated circuit applied, as likewise described above. Here, too, the abovementioned etching techniques can alternatively be used for structuring the metal layer. In this embodiment, the coupling element is to be recognized visually if the em- bossed lacquer layer, which forms the outermost layer facing the viewer in the finished security element, is transparent. If this effect is undesirable, the embossed lacquer layer can be colored. Preferably, metallic pigments are used for this purpose. Alterna- tively, the security element or security paper is laminated with a foil or provided with a print that hides the optical impression of the coupling element. This variant has the additional advantage that the layers of the security element ensuring the optical effect are undetachably connected with the machine-checkable integrated circuit. Manipulations of the layers producing the optical effect thus simul- taneously influence the machine-readable module. However, the coupling element need not necessarily consist of an accordingly formed metal layer. It can also be formed by a conductive polymer layer that is accord- ingly printed for example. The connection between coupling element and chip is effected in all embodi- ments either by electrically conductive connecting elements, such as conductive adhe- sives, tin-lead solder, etc., or contactlessly, e.g. capacitively. To make sure that manipulation by punching out a circuit together with the cou- pling element from a security element or a security paper provided therewith is no- ticed, the coupling element is preferably designed to cover a large area. The resulting punched holes would already be very striking visually even to a layman as of an area assumed by the coupling element of 20 square millimeters or more. The security paper provided with the inventive security elements can then be processed into any documents of value. If bank notes are produced from the security paper for example, the security paper is usually cut into sheets with a plurality of cop- ies that can then be processed in suitable printing machines. Each copy has at least one inventive security element. In a preferred embodiment, the security element is formed as a strip extending parallel to one of the edges of a copy. This has the advantage that the security element can be transferred to the security paper in a continuous process. During printing, the area of the security element can also be overprinted at least partially, thereby further increasing the forgery-proofness of the document of value, in particular if a tactile steel intaglio print is used for overprinting. However, the inven- tive security paper can also be used for producing other documents of value, such as passports, shares, visas, ID cards, certificates, admission tickets, accompanying docu- ments for transportation, security labels or checks, etc. The documents of value can in turn be fastened as antiforgery elements to any products, such as CDs, perfumes, pharmaceutical products, packages of all types. The forgery-proofness of the inventive document of value can be increased even further by storing certain data relevant to the document of value in the integrated cir- cuit in checkable fashion. For example, the history of use of the document of value can be stored in the integrated circuit. With bank notes for example, information about their issue and further life can be stored, thus permitting a hitherto hardly possible evaluation of the circulation behavior of the notes. It is equally possible to store infor- mation about fitness or unfitness for circulation of bank notes. Further, it is possible to mark or block documents of value for certain applica- tions. Such marking could open up especially advantageous possibilities in dealing with blackmailing money. In a special embodiment, the integrated circuit of the security element can be ad- ditionally equipped or connected with a photosensitive sensor that is likewise con- tained in the security paper or the security element and recognizes for example inci- dent light, heat, magnetism and other properties. The measured values of such sensors are transmitted to the integrated circuit and stored there. This makes it possible for ex- ample to record each copying operation of a document as incident light and to store the number of copying operations in the integrated circuit. This offers the advantage of making it possible to distinguish between legal and illegal copies. When a legal copy is made, the user is aware that there is a corresponding sensor in the security paper so that he can then erase the information about his legal duplication using a device avail- able only to him. Illegal duplication is not erased, however. If a check is done before each copying operation of whether the corresponding memory of the integrated circuit the integrated circuit has an entry, further copies can be prevented. This procedure is suitable in particular for documents that are usually stored sealed from light. Alternatively, identification numbers of the individual copying machines can also be stored in the integrated circuit. This opens up the possibility that all machines used for producing copies can be identified at a later time. This can be useful when tracing forgers. Finally, copying machines can also be equipped with corresponding readers that prevent a copying operation of the document of value when reading a correspond- ing marking from the integrated circuit. The integrated circuit can further be used for storing a type of electronic stamp of an issuing authority. This is of advantage in particular with visas or passports. For this purpose it is expedient to provide each document of value with individual information. This may be simple random numbers or more complex information which can include features peculiar to the document, such as special printing tolerances, transmission properties of the paper or the like. This information can further be encoded crypto- graphically. However, the integrated circuit can also be used for protecting the legible infor- mation applied to the document of value. For example, if identification information such as a number and an indication of the issuer is entered on a document of value, the corresponding information can also be stored in the integrated circuit. Storage of this information is preferably effected in encrypted form that can only be identified with the matching counter key. Upon a check of the document of value, the information contained in the integrated circuit is compared with the information actually present legibly on the document. If communication with the integrated circuit is effected contactlessly, the han- dling of such documents is relatively simple. They can then be used for example to perform a virtually complete check in connection with goods deliveries, border cross- ings and other operations by which flows of goods are handled together with docu- ments. The invention can be used for example to check smuggling operations. If a microprocessor is used as an integrated circuit, information encrypted by suitable cryptographic methods can moreover be produced in the integrated circuit of the security paper or document of value and transferred to a read/write device. Any other programs or multifunctional structures can also be used. Techniques known from data processing or from the field of smart-card technology can be used here. Further examples and advantages of the invention will be explained with refer- ence to the figures of the accompanying drawings. It is pointed out that the figures are only for illustration and do not show the invention true to scale. Fig. 1 shows an inventive document of value, Figs. 2 to 5 show different embodiments of the inventive transfer material in cross section, Figs. 6a) to 6e) show different examples of the inventive coupling element. Fig. 1 shows a variant of the inventive document of value in a top view. The ex- ample shown involves bank note 1 produced from the inventive security paper. The bank note bears inventive security element 2 executed as a transfer element and ap- plied using the transfer material explained in more detail hereinafter. Bank note 1 can have additional security elements, for example security thread 3. Security thread 3 is quasi woven into the paper as a so-called "window security thread" so that it passes to the surface of the bank note in certain areas 4. Figs. 2 to 5 show different embodiments of inventive transfer material 10. Trans- fer material 10 consists fundamentally of carrier layer 5 and transfer layer 6 that is transferred to the inventive document of value at least in certain areas. In the case of security element 2 shown in Fig. 1, transfer layer 6 is detached from carrier layer 5 in the form of a square for example. Carrier layer 5 can be provided with a separation layer to guarantee defined detachment of the transfer layer. This separation layer is not shown in the figures. Any other contour forms are of course also possible, including filigree structures such as guilloches, etc. Security elements 2 frequently also have the form of strips disposed parallel to security thread 3. Transfer layer 6 shown in Fig. 2 consists of layer 7 producing the optical effect, integrated circuit 8 and adhesive layer 9. Since integrated circuit 8 already has an inte- grated coupling element, no further layers for communication with the integrated cir- cuit are to be provided in the layer structure of transfer layer 6. Layer 7 producing the optical effect is therefore freely selectable. However, it is preferably opaque at least in the area of integrated circuit 8 so that integrated circuit 8 is not recognizable visually. Layer 7 producing the optical effect is shown all over here and can in turn be composed of a plurality of layers. This is the case for example if it is a thin-film ele- ment, which can be composed of a plurality of dielectric layers with different refrac- tive indexes and thin metal layers. Such a layer structure produces an angle-dependent interplay of colors. Layer 7 can also be any other layer producing an optical effect, for example a printed layer containing special pigments producing an optically variable effect. For this purpose liquid-crystal pigments or other pigments exploiting interference effects are preferably used, for example IRIODINE® from the Merck company. Adhesive layer 9 serves to fasten security element 2 to the document of value. It is preferably a hot-melt adhesive layer that is activated with the aid of suitably formed hot-stamping dies. However, adhesive layer 9 can also be provided only in certain ar- eas to already define the contour form of the transfer elements to be transferred on the transfer material. According to a further embodiment, it can also be completely absent. In this case the adhesive layer is applied in the desired form to the substrate that is to be provided with a transfer element. The transfer material shown in Fig. 3 is provided with an integrated circuit not having an integrated coupling element. Transfer layer 6 therefore contains not only all- over layer 7 producing an optical effect but also metal layer 11. Metal layer 11 is ap- plied in the form of a folded dipole, as shown in Fig. 6a), and forms the coupling ele- ment for integrated circuit 8. The connection between the terminals of folded dipole 11 and the contact areas of the integrated circuit is effected via conductive adhesive layer 12. Transfer layer 6 shown in Fig. 4 has a hologram consisting of embossed layer 13 and metal layer 14. Metal layer 14 ensures that the relief-like diffraction structures of the hologram can be observed in reflected light. However, metal layer 14 has spaces 19. Spaces 19 are formed so as to result in coupling element 11 for integrated circuit 8. As in Fig. 3, the coupling element is formed by a folded dipole insulated from the rest of metal layer 14 by spaces 19. In this example, metal layer 14 is simultaneously part of layer 7 producing the optical effect and of integrated circuit 8. However, coupling element 11 is to be clearly recognized in a top view if embossed layer 13 is of transparent design. If this effect is not desired, embossed layer 13 can be colored with translucent colors. It is also possi- ble to use nonconductive, metallic-looking pigments that blur the optical impression of coupling element 12. Transfer layer 6 shown in Fig. 5 likewise shows a hologram combined with an integrated circuit. In the present case, reflecting layer 14 of the diffraction structure does not serve simultaneously as a communication layer for integrated circuit 8. Rather, metal layer 14 is separated from metal layer 1 7 having coupling element 11 by insulating layer 15. Nevertheless, metal layer 14 has gaps 16 in the form of characters or patterns that are well readable at least in transmitted light. These gaps form a further visual authenticity feature. Metal layer 17 containing coupling element 11 is constructed analogously to re- flecting layer 14 shown in Fig. 4. That is, it has spaces 19 that insulate coupling ele- ment 11 from the rest of the metal layer. Gaps 16 and spaces 19 in metal layers 14 and 17 can be produced in different ways. For example, the metal layers can be vapor-deposited by means of correspond- ing masks in the desired form directly on particular layer 13, 15. Alternatively, the metal layers can also be produced in a first step as all-over metal layers, which are then covered with a protective layer in the desired areas. The non-covered free areas are then removed with the aid of suitable solvents. These removed areas correspond to gaps 16 or spaces 19. However, the method preferably used is to print layer 13, 15 in a first step with a preferably water-soluble ink in areas 16, 19. An all-over metalization is then applied by vapor deposition. In a last step, the soluble ink and the metal layer disposed there- above are removed with a corresponding solvent so that gaps 16 or spaces 19 arise. It is likewise possible to produce gaps 16 using a different method from that for produc- ing spaces 19. The same methods can of course also be used for producing coupling element 11 as shown in Fig. 3. Fig. 6 shows different embodiments of the coupling element. What is shown in each case is solely the coupling element as used for example in Fig. 3. Any further metallic surroundings possibly present, as shown in Fig. 4 and 5, have been omitted for clarity's sake,. Fig. 6a) shows a folded dipole, which can additionally be provided with a metal- lic core to increase the power of the system, as shown in Fig. 6b). Alternatively, the coupling element can also be executed as a coil with a corresponding number of turns or with a metallic core, as shown in Figs. 6c) and 6d). A further capacitively operable variant is shown in Fig. 6e). The two metallic bars act as an open dipole here. These forms of coupling elements can of course be used in all examples shown and de- scribed. As explained above, these coupling elements are preferably produced by a corre- sponding metalization or demetalizing. However, they can alternatively be produced by printing technology with the aid of conductive polymers. The layer structures of transfer material 10 shown in Figs. 2 to 5 can be trans- ferred analogously to a security thread. In this case, carrier layer 5 is replaced with a plastic foil undetachably connected with the layer structure disposed thereon. The layer structure here corresponds to transfer layers 6 shown. This security thread can be woven into the security paper analogously to security thread 3 shown in Fig. 1. How- ever, the security thread can alternatively be disposed completely on the surface of the security paper or document of value. For this purpose the surface of the plastic carrier carrier opposite the layer structure is coated with a suitable adhesive. Analogously, it is possible to produce the security element as a self-supporting adhesive label with any contour form. CLAIMS : 1. A security paper for producing documents of value, such as bank notes, certifi- cates, etc., with at least one multilayer security element having at least one visu- ally checkable optical effect, the security element being disposed at least partly on the surface of the security paper, characterized in that the security element has at least one integrated circuit. 2. A security paper according to claim 1, wherein the security element shows an optically variable effect whereby the security element produces differ- ent visual impressions at different viewing angles. 3. A security paper according to claim 1 or 2, wherein the security ele- ment has at least one layer containing optically variable pigments, in particular interference-layer or liquid-crystal pigments. 4. A security paper according to at least one of claims 1 to 3, wherein the security element has at least one layer in which diffraction structures in the form of a relief structure are present. 5. A security paper according to claim 4, wherein the diffraction struc- tures are combined at least in certain areas with a reflecting layer, in particular a metal layer or a dielectric layer with a high refractive index. 6. A security paper according to at least one of claims 1 to 5, wherein the security element has at least a metallic and a dielectric layer or at least two dielectric layers with different refractive indexes, the layers cooperating so that different visual impressions arise when viewed in reflected light at different viewing angles. 7. A security paper according to at least one of claims 1 to 6, wherein the integrated circuit is disposed between the layers having the optical effect and the security paper. 8. A security paper according to at least one of claims 1 to 7, wherein the energy supply for the integrated circuit is effected contactlessly via a cou- pling element. 9. A security paper according to claim 8, wherein the coupling element is part of the integrated circuit. 10. A security paper according to claim 8, wherein the coupling element is disposed in a layer of the security element. 11. A security paper according to claim 10, c wherein the integrated circuit is connected with the coupling element. 12. A security paper according to claim 10 or 11, wherein the security ele- ment has at least one metallic layer in which the coupling element is formed. 13. A security paper according to claim 12, wherein the metallic layer is separated from the layers producing the optical effect by an insulating layer. 14. A security paper according to claim 12, wherein the metallic layer is at the same time one of the layers producing the optical effect. 15. A security paper according to at least one of claims 8 to 14, wherein the coupling element is a folded dipole, a coil or an open dipole. 16. A security paper according to claim 15, wherein the folded dipole or the coil has a metalized core zone. 17. A security paper according to at least one of claims 1 to 16, wherein the integrated circuit is a memory chip or a microprocessor chip. 18. A security paper according to at least one of claims 1 to 17, wherein the security element is a transfer element or a label disposed completely on the surface of the security paper. 19. A security paper according to claim 18, wherein the security element has the form of a strip. 20. A security paper according to at least one of claims 1 to 17, wherein the security element is a security thread. 21. A security paper according to at least one of claims 8 to 19, wherein the coupling element occupies an area of at least 20 square millimeters. 22. A security paper according to at least one of claims 1 to 21, wherein the security element is so connected with the security paper that they cannot be separated nondestructively. A document of value with at least one multilayer security element having at least one visually checkable optical effect, the security element being disposed com- pletely on the surface of the document of value, characterized in that the security element has at least one integrated circuit. 24. A document of value according to claim 23, wherein the document of value is a passport, a bank note or a credit card. 25. A document of value according to claim 23 or 24, wherein the docu- ment of value has a security paper according to at least one of claims 1 to 22. 26. A document of value according to at least one of claims 23 to 25, wherein the document of value has a print, in particular an intaglio print, at least overlapping with the security element. 27. A multilayer security element for application to a document of value, the security element having at least one visually checkable optical effect, characterized in that the security element has at least one integrated circuit. 28. A transfer material for applying a multilayer security element to a document of value, the transfer material having a carrier layer on which the layer structure of the security element is detachably prepared, and the security element having at least one visually checkable optical effect, characterized in that the layer struc- ture of the security element has at least one integrated circuit. 29. A transfer material according to claim 28, wherein the transfer mate- rial has the following layer structure: a carrier layer, at least one layer producing the optical effect, and at least one integrated circuit. 30. A transfer material according to claim 29, wherein the layer produc- ing the optical effect is a printed layer containing optically variable pigments, in particular interference-layer or liquid-crystal pigments. 31. A transfer material according to at least one of claims 28 to 30, wherein the transfer material has the following layer structure: a carrier layer, a layer in which diffraction structures in the form of a relief structure are present, a metal layer in which a coupling element is formed, an integrated circuit, and a hot-melt adhesive layer. 32. A transfer material according to at least one of claims 28 to 30, wherein the transfer material has the following layer structure: a carrier layer, a layer in which diffraction structures in the form of a relief structure are present, a reflecting layer permitting the diffraction structures to be observed in re- flected light, an insulating layer. a metal layer in which a coupling element is formed, an integrated circuit, and a hot-melt adhesive layer. 33. A transfer material according to claim 31 or 32, wherein the inte- grated circuit is connected with the coupling element via a conductive adhesive layer. 34. A transfer material according to claim 33, wherein the conductive adhesive layer is a conductive silver layer or an anisotropic conductive adhesive layer. 35. A transfer material according to at least one of claims 28 to 34, wherein the coupling element is a folded dipole, a coil or an open dipole. 36. A transfer material according to at least one of claims 28 to 35, wherein the integrated circuit is a memory chip or a microprocessor chip. 37. A transfer material according to at least one of claims 29 to 34, wherein the transfer layer of the transfer material is formed as a non-self-supporting foil. 38. A method for producing a transfer material for applying a multilayer security element to a document of value, the transfer material having a carrier layer on which the layer structure of the security element is detachably prepared, and the security element having at least one visually checkable optical effect, character- ized in that at least one integrated circuit is incorporated into the layer structure of the security element. 39. A method according to claim 38, wherein the following steps are carried out: a) providing a carrier layer, b) applying at least one layer producing an optical effect, c) vapor-depositing a metallic layer, a coupling element being formed in the metallic layer, d) applying an integrated circuit. 40. A method according to claim 39, wherein before step c) a soluble ink is printed on in the form of the coupling element and any further patterns or char- acters, and that after step c) said ink is removed together with the metallic layer. 41. A method according to claim 39 or 40, wherein the integrated circuit and the coupling element are interconnected via a conductive silver layer or an anisotropic conductive adhesive layer. 42. A method according to at least one of claims 39 to 41, wherein in step b) a layer is applied into which diffraction structures in the form of a relief structure are then embossed. 43. A method according to claim 42, wherein in step c) a UV-curable lac- quer layer is applied that is cured during the embossing operation. 44. A method according to claim 42 or 43, wherein in step b) a reflecting layer is applied to the embossed layer at least in certain areas. 45. A method according to at least one of claims 39 to 41, wherein in step b) at least a metallic and a dielectric layer or at least two dielectric layers with different refractive indexes are applied, the layers cooperating so that differ- ent visual impressions arise when viewed in reflected light at different viewing an- gles. 46. A method according to at least one of claims 39 to 45, wherein an insulating layer is disposed between the layers producing the optical effect and the metal layer to be applied in step c). 47 A method according to at least one of claims 39 to 45, wherein - in a step e) an adhesive layer, preferably a hot-melt adhesive layer, is applied. 48. A method for producing a document of value with a security element, character- ized in that the layer structure of the transfer material according to at least one of least one of claims 28 to 37 is transferred to the document of value in certain ar- eas and the carrier layer is then removed. The invention relates to a security paper for producing documents of value (1), such as bank notes, certificates, etc., with at least one multilayer security element (2). The security element is disposed at least partly on the surface of the security paper and has at least one visually checkable optical effect (7) and at least one integrated circuit (8).

Full Text

"SECURITY PAPER FOR PRODUCING DOCUMENTS OF VALUE,
AND METHOD OF ITS PRODUCTION"
This invention relates to a security paper for producing documents of value, such
as bank notes, certificates, etc., with at least one multilayer security element having at
least one visually checkable optical effect, the security element being disposed at least
partly on the surface of the security paper. The invention further relates to a multilayer
security element and to a document of value with such a security element. A transfer
material for applying a multilayer security element to a document of value and a
method for producing the transfer material and the document of value are also the sub-
ject matter of the invention.
There is a constant interest in protecting papers of value against forgery and un-
authorized reproduction. It is becoming ever more difficult, particularly in view of to-
day's copying and printing techniques, to find effective security features that at least
make unauthorized reproduction or forgery clearly recognizable, if they do not actually
prevent it.
EP 0019 191 B1 proposes for example providing a paper of value with an inte-
grated circuit in which a checkable coding is written, the communication with the inte-
grated circuit preferably being effected contactlessly via antennas. The integrated cir-
cuit is set in the gap of an at least partly metalized carrier foil. This foil is then lami-
nated between two paper webs. Since the carrier foil is only laminated in between the
two paper webs, however, there is the danger that the layers can be separated from
each other relatively easily so that the plastic inlay provided with the chip can be used
for possible forgeries. Further, this security element is a strictly machine-checkable
security element that can only be checked by means of special detectors.
Frequently used authenticity features that are very easily visually checked and
very striking are optically variable security elements, for example holograms, that
show different visual impressions, such as color effects or information, from different
viewing angles. A paper of value with such a security element is known from EP 0 440
045 A2. A bank note is described here that is provided with a label-like hologram.
Since the optically variable effect of the hologram cannot be rendered by a color cop-
ier, these security elements offer very good protection against color copying. However,

However, these security elements have the disadvantage that they are very poorly
checkable by machine, since the radiation reflected by the diffraction structures of the
hologram must be detected at certain solid angles and the influence of stray radiation
largely excluded to permit reliable ascertainment of the presence of a certain
hologram. A further problem is the fluctuating signal intensity, since the latter is
greatly dependent on the illumination source of the hologram. For reliable measure-
ment, defined lighting conditions must therefore be ensured.
To avoid this problem, it was therefore also proposed to superimpose a visually
readily visible hologram with a strictly machine-readable laser transmission hologram
(DE 38 40 037 C2). Readout of the machine-readable hologram can be effected only
by means of a laser, the information hidden in this laser transmission hologram being
projected onto a certain space coordinate in front of the document of value that is al-
ready defined when the hologram is recorded. The detector must be located at this
place to permit this hidden information to be recognized. However, this type of visual
and machine protection for a document of value is very elaborate both to produce and
to check.
The invention is therefore based on the problem of proposing a document of
value and a security paper with a security element having a visually checkable optical
effect and also being checkable by machine, the security paper and document of value
being preferably easy and cost-effective to produce.
This problem is solved by the features of the independent claims. Developments
are the subject matter of the subclaims.
According to the invention, "security paper" designates the unprinted paper that
can have not only the inventive security element but also further authenticity features,
such as luminescent substances provided in the volume, a security thread or the like. It
is usually present in quasi endless form and is processed further at a later time.
"Document of value" refers to a document that is finished for its intended use. It
may be for example a printed paper of value, such as a bank note, certificate or the
like, an ID card, a passport or another document requiring protection.

The invention will be described hereinafter with reference to the security paper.
However, the advantages and embodiments apply analogously to documents of value.
According to the invention, the security paper is provided with at least one multi-
layer security element having an optical effect that can be easily checked visually and
not rendered by copying technology, or only in falsified form. This security element is
disposed at least partly on the surface of the security paper and contains at least one
integrated circuit in one of its inside layers. This integrated circuit is for example a
strict memory chip (ROM), a rewritable chip (EPROM, EEPROM) or a microproces-
sor chip. The chips used have a thickness of 5 microns to 50 microns, preferably 10 mi-
crons, and an edge length of about 0.1 millimeters to 3 millimeters, preferably 0.6 mil-
limeters. On the chip there are preferably two to four contact surfaces.
The optical effect of the security element can be produced by a layer containing
optically variable pigments, in particular interference-layer or liquid-crystal pigments.
This layer can be present all over or in the form of information. Alternatively, the se-
curity element can also have a hologram, kinegram or other diffraction structure. Pref-
erably, the diffraction structures are embossed into a plastic layer in the form of a re-
lief structure. If the diffraction structures are to be observable in reflected light, they
are combined with a reflecting layer, in particular a metal layer or a dielectric layer
with a high refractive index. The reflecting layer need not be provided all over, how-
ever, but can be applied in the form of a screen or any other information. In particular,
it can have gaps in the form of patterns or characters. A further possibility for produc-
ing a visually checkable optical effect is to use thin-film structures wherein metallic
and/or dielectric layers with different refractive indexes are disposed one above the
other, the layers cooperating so that different visual impressions arise at different
viewing angles at least when viewed in reflected light. These different visual impres-
sions are preferably different color effects.
Alternatively, the optical effect can also be produced by any printed image or a
metallic layer with gaps in the form of patterns, characters or the like. The metal layer
itself can likewise be present in the form of characters or patterns. The use of special

printing inks, such as luminescent inks, is also possible. Of course, a plurality of secu-
rity features producing an optical effect can also be used. When a layer producing an
optical effect is spoken of below, this also refers to cooperating multilayer structures,
such as the abovementioned dielectric thin-film elements or combinations of a plural-
ity of layers that produce different optical effects. The term "hologram" is likewise
intended to stand for any diffraction structures.
The inventive integrated circuit is preferably disposed between this layer having
the optical effect and the security paper. It is thus protected outwardly from environ-
mental influences and practically does not appear visually. It is advantageous to use
integrated circuits with which communication is effected contactlessly via a coupling
element. The coupling element can already be an integrated part of the integrated cir-
cuit or be disposed in a layer of the security element. Integration of the coupling ele-
ment into the layer structure of the security element involves the advantage that in case
of attempted manipulation or forgery the circuit cannot be separated operably from an
original security element or a security paper equipped therewith, for example to be
incorporated into a counterfeit reproduction. The coupling element can be a folded
dipole, a coil or an open dipole. To increase the effectiveness of the system, the folded
dipole or the coil can also have a metalized core zone. If the coupling element is
formed on the layer producing the optical effect, the filled core zone also causes the
visual impression of the layer to be less disturbingly influenced by the coupling ele-
ment. The read range is between about 0.1 millimeters and a few centimeters depend-
ing on the type of coupling element and the selected read/write frequency, for example
13.56 megahertz and 2 gigahertz.
The inventive security element is preferably applied to the security paper after
papermaking and is so connected with the security paper that it cannot be removed
without destroying the security paper or the security element. The invention thus has
the advantage that the security element does not have to be integrated into the paper-
making process and is nevertheless connected with the paper of value in forgery-proof
fashion. A further advantage is that the security element is protected against attempts
at forgery in several respects. The optical effect of the layers facing the viewer cannot
be rendered true to the original with copying machines or other reproduction tech-

reproduction techniques, so that such attempts at forgery can already be visually
recognized easily and fast. If an attempt to reproduce or imitate the optical impression
of the security element should succeed, however, the forgery can nevertheless be
recognized upon the machine check of the integrated circuit. Since the circuit is
disposed inside the security element and covered by the layers producing the optical
effect, a potential forger will not notice this additional authenticity feature and
therefore not attempt to imitate it.
The inventive security element is preferably formed as a multilayer self-support-
ing label or as a transfer element that is connected with the security paper after its pro-
duction. The contour form of the security element is freely selectable. Alternatively,
the secuirity element can also be formed as a security thread. In this case, the integrated
circuit and the layer producing the optical effect are disposed on a thread-shaped plas-
tic substrate that is so incorporated into the paper web during papermaking that the
thread passes directly to the surface of the security paper in partial areas. According to
a preferred embodiment, the security thread consists of two plastic substrates between
which the integrated circuit and the layer producing the optical effect are disposed.
A "transfer element" refers according to the invention to a security element that
is prepared on a separate carrier layer, for example a plastic foil, in the reverse order as
it later comes to lie on the security paper, and then transferred to the security paper by
means of an adhesive or lacquer layer in the desired contour forms. The carrier layer
can be removed from the layer structure of the security element after transfer, or re-
main a firm part of the security element on the layer structure as a protective layer.
The individual transfer elements can be prepared on the carrier layer as separate
individual elements in the contour forms to be transferred. Alternatively, the layer se-
quence of the transfer elements is provided on the carrier layer in continuous form.
Such carrier layers with spaced-apart individual transfer elements or a continuously
extending layer structure will hereinafter be referred to as "transfer material," and the
layer sequence of the security element disposed on the carrier layer as the "transfer
layer."

In the case of the continuous transfer layer, the transfer material is then con-
nected with the security paper via an adhesive layer, and the adhesive layer activated
via suitable embossing tools so that the transfer layer adheres to the security paper
only in the activated areas. All other areas are then removed with the carrier layer. Al-
ternatively, the adhesive layer can also be executed in the form of the security element
to be transferred. Adhesives preferably used are hot-melt adhesives. However, any
other adhesives, such as reaction lacquers, can also be used.
The security element can alternatively be applied to the document of value. The
embodiments and fastening possibilities described in connection with the security pa-
per apply analogously in this case.
Hereinafter, some preferred layer sequences of the inventive security element
will be explained in more detail by the example of the transfer material.
The analogous layer sequence, only in the accordingly reverse order of layers,
can of course also be used for labels and security threads.
In the simplest form, the transfer material consists of a carrier layer, in particular
a transparent plastic foil, at least one layer producing the optical effect and at least one
integrated circuit. In this embodiment the integrated circuit also contains the coupling
element for communication with a read/write device.
If an integrated circuit not having an integrated coupling element is used, a suit-
able coupling element must be provided in the layer structure of the transfer layer of
the transfer material. The transfer layer with the integrated coupling element is then
preferably formed as a thin, non-self-supporting foil. This thwarts attempts at forgery
that aim at detaching the original security element from a security paper, since the
non-self-supporting security element is not removable without being damaged.
This coupling element can be an open dipole, a folded dipole or a coil. This cou-
pling element is preferably produced by suitable demetalizings in a metal layer. For
this purpose the carrier layer of the transfer material, which is optionally provided with
a separation layer, is provided with the layer producing the optical effect. On this layer

layer a water-soluble or other layer soluble by means of a solvent is then printed in the
form of the areas to be demetalized. In the next step, the carrier layer is metalized com-
pletely on the printed side. In a last step, the soluble ink and the metalization present in
these areas are removed. The integrated circuit is fastened to this layer by means of a
conductive adhesive layer, for example conductive silver or an anisotropic conductive
adhesive. Finally, the carrier layer is provided with an adhesive layer at least in certain
areas.
Alternatively, the structuring of the metal layer can also be effected by means of
known etching techniques. In this connection, the carrier layer is provided directly
with the all-over metalization after application of the layer producing the optical ef-
fect. The metal layer is then printed with a protective lacquer layer in the form of the
desired coupling element. The non-covered areas are then removed with suitable sol-
vents. The protective layer can also be produced by photographic means by coating the
metal layer all over with a photoresist that is then exposed and developed.
According to a variant, the metallic layer forming the coupling element can be
separated from the layer producing the optical effect by an insulating layer. This is
necessary in particular when the layer producing the optical effect likewise has a con-
ductive layer.
According to a further embodiment of the invention, however, it is also possible
that the metallic layer is at the same time required for the visually optical effect. If a
reflection hologram is used for example, the layer producing the optical effect usually
consists of an embossed lacquer layer in which the diffraction structures of the holo-
gram are embossed in the form of a relief structure, and a metal layer. The carrier layer
of the transfer material is first provided with the embossed lacquer layer in which the
diffraction structures are embossed. This lacquer layer is then provided with a metal
layer. Before the metal layer is preferably vapor-deposited, however, a soluble ink is
printed on for producing the coupling element, as explained above. After metalization,
the soluble ink is removed and the integrated circuit applied, as likewise described
above. Here, too, the abovementioned etching techniques can alternatively be used for
structuring the metal layer.

In this embodiment, the coupling element is to be recognized visually if the em-
bossed lacquer layer, which forms the outermost layer facing the viewer in the finished
security element, is transparent. If this effect is undesirable, the embossed lacquer
layer can be colored. Preferably, metallic pigments are used for this purpose. Alterna-
tively, the security element or security paper is laminated with a foil or provided with a
print that hides the optical impression of the coupling element.
This variant has the additional advantage that the layers of the security element
ensuring the optical effect are undetachably connected with the machine-checkable
integrated circuit. Manipulations of the layers producing the optical effect thus simul-
taneously influence the machine-readable module.
However, the coupling element need not necessarily consist of an accordingly
formed metal layer. It can also be formed by a conductive polymer layer that is accord-
ingly printed for example.
The connection between coupling element and chip is effected in all embodi-
ments either by electrically conductive connecting elements, such as conductive adhe-
sives, tin-lead solder, etc., or contactlessly, e.g. capacitively.
To make sure that manipulation by punching out a circuit together with the cou-
pling element from a security element or a security paper provided therewith is no-
ticed, the coupling element is preferably designed to cover a large area. The resulting
punched holes would already be very striking visually even to a layman as of an area
assumed by the coupling element of 20 square millimeters or more.
The security paper provided with the inventive security elements can then be
processed into any documents of value. If bank notes are produced from the security
paper for example, the security paper is usually cut into sheets with a plurality of cop-
ies that can then be processed in suitable printing machines. Each copy has at least one
inventive security element. In a preferred embodiment, the security element is formed
as a strip extending parallel to one of the edges of a copy. This has the advantage that
the security element can be transferred to the security paper in a continuous process.

During printing, the area of the security element can also be overprinted at least
partially, thereby further increasing the forgery-proofness of the document of value, in
particular if a tactile steel intaglio print is used for overprinting. However, the inven-
tive security paper can also be used for producing other documents of value, such as
passports, shares, visas, ID cards, certificates, admission tickets, accompanying docu-
ments for transportation, security labels or checks, etc. The documents of value can in
turn be fastened as antiforgery elements to any products, such as CDs, perfumes,
pharmaceutical products, packages of all types.
The forgery-proofness of the inventive document of value can be increased even
further by storing certain data relevant to the document of value in the integrated cir-
cuit in checkable fashion. For example, the history of use of the document of value can
be stored in the integrated circuit. With bank notes for example, information about
their issue and further life can be stored, thus permitting a hitherto hardly possible
evaluation of the circulation behavior of the notes. It is equally possible to store infor-
mation about fitness or unfitness for circulation of bank notes.
Further, it is possible to mark or block documents of value for certain applica-
tions. Such marking could open up especially advantageous possibilities in dealing
with blackmailing money.
In a special embodiment, the integrated circuit of the security element can be ad-
ditionally equipped or connected with a photosensitive sensor that is likewise con-
tained in the security paper or the security element and recognizes for example inci-
dent light, heat, magnetism and other properties. The measured values of such sensors
are transmitted to the integrated circuit and stored there. This makes it possible for ex-
ample to record each copying operation of a document as incident light and to store the
number of copying operations in the integrated circuit. This offers the advantage of
making it possible to distinguish between legal and illegal copies. When a legal copy
is made, the user is aware that there is a corresponding sensor in the security paper so
that he can then erase the information about his legal duplication using a device avail-
able only to him. Illegal duplication is not erased, however. If a check is done before
each copying operation of whether the corresponding memory of the integrated circuit

the integrated circuit has an entry, further copies can be prevented. This procedure is
suitable in particular for documents that are usually stored sealed from light.
Alternatively, identification numbers of the individual copying machines can also
be stored in the integrated circuit. This opens up the possibility that all machines used
for producing copies can be identified at a later time. This can be useful when tracing
forgers. Finally, copying machines can also be equipped with corresponding readers
that prevent a copying operation of the document of value when reading a correspond-
ing marking from the integrated circuit.
The integrated circuit can further be used for storing a type of electronic stamp of
an issuing authority. This is of advantage in particular with visas or passports. For this
purpose it is expedient to provide each document of value with individual information.
This may be simple random numbers or more complex information which can include
features peculiar to the document, such as special printing tolerances, transmission
properties of the paper or the like. This information can further be encoded crypto-
graphically.
However, the integrated circuit can also be used for protecting the legible infor-
mation applied to the document of value. For example, if identification information
such as a number and an indication of the issuer is entered on a document of value, the
corresponding information can also be stored in the integrated circuit. Storage of this
information is preferably effected in encrypted form that can only be identified with
the matching counter key. Upon a check of the document of value, the information
contained in the integrated circuit is compared with the information actually present
legibly on the document.
If communication with the integrated circuit is effected contactlessly, the han-
dling of such documents is relatively simple. They can then be used for example to
perform a virtually complete check in connection with goods deliveries, border cross-
ings and other operations by which flows of goods are handled together with docu-
ments. The invention can be used for example to check smuggling operations.

If a microprocessor is used as an integrated circuit, information encrypted by
suitable cryptographic methods can moreover be produced in the integrated circuit of
the security paper or document of value and transferred to a read/write device. Any
other programs or multifunctional structures can also be used. Techniques known from
data processing or from the field of smart-card technology can be used here.
Further examples and advantages of the invention will be explained with refer-
ence to the figures of the accompanying drawings. It is pointed out that the figures are only for illustration and do not
show the invention true to scale.
Fig. 1 shows an inventive document of value,
Figs. 2 to 5 show different embodiments of the inventive transfer material in
cross section,
Figs. 6a) to 6e) show different examples of the inventive coupling element.
Fig. 1 shows a variant of the inventive document of value in a top view. The ex-
ample shown involves bank note 1 produced from the inventive security paper. The
bank note bears inventive security element 2 executed as a transfer element and ap-
plied using the transfer material explained in more detail hereinafter. Bank note 1 can
have additional security elements, for example security thread 3. Security thread 3 is
quasi woven into the paper as a so-called "window security thread" so that it passes to
the surface of the bank note in certain areas 4.
Figs. 2 to 5 show different embodiments of inventive transfer material 10. Trans-
fer material 10 consists fundamentally of carrier layer 5 and transfer layer 6 that is
transferred to the inventive document of value at least in certain areas. In the case of
security element 2 shown in Fig. 1, transfer layer 6 is detached from carrier layer 5 in
the form of a square for example. Carrier layer 5 can be provided with a separation
layer to guarantee defined detachment of the transfer layer. This separation layer is not
shown in the figures. Any other contour forms are of course also possible, including
filigree structures such as guilloches, etc. Security elements 2 frequently also have the
form of strips disposed parallel to security thread 3.

Transfer layer 6 shown in Fig. 2 consists of layer 7 producing the optical effect,
integrated circuit 8 and adhesive layer 9. Since integrated circuit 8 already has an inte-
grated coupling element, no further layers for communication with the integrated cir-
cuit are to be provided in the layer structure of transfer layer 6. Layer 7 producing the
optical effect is therefore freely selectable. However, it is preferably opaque at least in
the area of integrated circuit 8 so that integrated circuit 8 is not recognizable visually.
Layer 7 producing the optical effect is shown all over here and can in turn be
composed of a plurality of layers. This is the case for example if it is a thin-film ele-
ment, which can be composed of a plurality of dielectric layers with different refrac-
tive indexes and thin metal layers. Such a layer structure produces an angle-dependent
interplay of colors.
Layer 7 can also be any other layer producing an optical effect, for example a
printed layer containing special pigments producing an optically variable effect. For
this purpose liquid-crystal pigments or other pigments exploiting interference effects
are preferably used, for example IRIODINE® from the Merck company.
Adhesive layer 9 serves to fasten security element 2 to the document of value. It
is preferably a hot-melt adhesive layer that is activated with the aid of suitably formed
hot-stamping dies. However, adhesive layer 9 can also be provided only in certain ar-
eas to already define the contour form of the transfer elements to be transferred on the
transfer material. According to a further embodiment, it can also be completely absent.
In this case the adhesive layer is applied in the desired form to the substrate that is to
be provided with a transfer element.
The transfer material shown in Fig. 3 is provided with an integrated circuit not
having an integrated coupling element. Transfer layer 6 therefore contains not only all-
over layer 7 producing an optical effect but also metal layer 11. Metal layer 11 is ap-
plied in the form of a folded dipole, as shown in Fig. 6a), and forms the coupling ele-
ment for integrated circuit 8. The connection between the terminals of folded dipole 11
and the contact areas of the integrated circuit is effected via conductive adhesive layer
12.

Transfer layer 6 shown in Fig. 4 has a hologram consisting of embossed layer 13
and metal layer 14. Metal layer 14 ensures that the relief-like diffraction structures of
the hologram can be observed in reflected light. However, metal layer 14 has spaces
19. Spaces 19 are formed so as to result in coupling element 11 for integrated circuit 8.
As in Fig. 3, the coupling element is formed by a folded dipole insulated from the rest
of metal layer 14 by spaces 19.
In this example, metal layer 14 is simultaneously part of layer 7 producing the
optical effect and of integrated circuit 8. However, coupling element 11 is to be clearly
recognized in a top view if embossed layer 13 is of transparent design. If this effect is
not desired, embossed layer 13 can be colored with translucent colors. It is also possi-
ble to use nonconductive, metallic-looking pigments that blur the optical impression of
coupling element 12.
Transfer layer 6 shown in Fig. 5 likewise shows a hologram combined with an
integrated circuit. In the present case, reflecting layer 14 of the diffraction structure
does not serve simultaneously as a communication layer for integrated circuit 8.
Rather, metal layer 14 is separated from metal layer 1 7 having coupling element 11 by
insulating layer 15. Nevertheless, metal layer 14 has gaps 16 in the form of characters
or patterns that are well readable at least in transmitted light. These gaps form a further
visual authenticity feature.
Metal layer 17 containing coupling element 11 is constructed analogously to re-
flecting layer 14 shown in Fig. 4. That is, it has spaces 19 that insulate coupling ele-
ment 11 from the rest of the metal layer.
Gaps 16 and spaces 19 in metal layers 14 and 17 can be produced in different
ways. For example, the metal layers can be vapor-deposited by means of correspond-
ing masks in the desired form directly on particular layer 13, 15. Alternatively, the
metal layers can also be produced in a first step as all-over metal layers, which are
then covered with a protective layer in the desired areas. The non-covered free areas
are then removed with the aid of suitable solvents. These removed areas correspond to
gaps 16 or spaces 19.

However, the method preferably used is to print layer 13, 15 in a first step with a
preferably water-soluble ink in areas 16, 19. An all-over metalization is then applied
by vapor deposition. In a last step, the soluble ink and the metal layer disposed there-
above are removed with a corresponding solvent so that gaps 16 or spaces 19 arise. It
is likewise possible to produce gaps 16 using a different method from that for produc-
ing spaces 19.
The same methods can of course also be used for producing coupling element 11
as shown in Fig. 3.
Fig. 6 shows different embodiments of the coupling element. What is shown in
each case is solely the coupling element as used for example in Fig. 3. Any further
metallic surroundings possibly present, as shown in Fig. 4 and 5, have been omitted
for clarity's sake,.
Fig. 6a) shows a folded dipole, which can additionally be provided with a metal-
lic core to increase the power of the system, as shown in Fig. 6b). Alternatively, the
coupling element can also be executed as a coil with a corresponding number of turns
or with a metallic core, as shown in Figs. 6c) and 6d). A further capacitively operable
variant is shown in Fig. 6e). The two metallic bars act as an open dipole here. These
forms of coupling elements can of course be used in all examples shown and de-
scribed.
As explained above, these coupling elements are preferably produced by a corre-
sponding metalization or demetalizing. However, they can alternatively be produced
by printing technology with the aid of conductive polymers.
The layer structures of transfer material 10 shown in Figs. 2 to 5 can be trans-
ferred analogously to a security thread. In this case, carrier layer 5 is replaced with a
plastic foil undetachably connected with the layer structure disposed thereon. The
layer structure here corresponds to transfer layers 6 shown. This security thread can be
woven into the security paper analogously to security thread 3 shown in Fig. 1. How-
ever, the security thread can alternatively be disposed completely on the surface of the
security paper or document of value. For this purpose the surface of the plastic carrier

carrier opposite the layer structure is coated with a suitable adhesive. Analogously, it
is possible to produce the security element as a self-supporting adhesive label with any
contour form.

CLAIMS :
1. A security paper for producing documents of value, such as bank notes, certifi-
cates, etc., with at least one multilayer security element having at least one visu-
ally checkable optical effect, the security element being disposed at least partly
on the surface of the security paper, characterized in that the security element has
at least one integrated circuit.
2. A security paper according to claim 1, wherein the security element
shows an optically variable effect whereby the security element produces differ-
ent visual impressions at different viewing angles.
3. A security paper according to claim 1 or 2, wherein the security ele-
ment has at least one layer containing optically variable pigments, in particular
interference-layer or liquid-crystal pigments.
4. A security paper according to at least one of claims 1 to 3, wherein
the security element has at least one layer in which diffraction structures in the
form of a relief structure are present.
5. A security paper according to claim 4, wherein the diffraction struc-
tures are combined at least in certain areas with a reflecting layer, in particular a
metal layer or a dielectric layer with a high refractive index.
6. A security paper according to at least one of claims 1 to 5, wherein
the security element has at least a metallic and a dielectric layer or at least two
dielectric layers with different refractive indexes, the layers cooperating so that
different visual impressions arise when viewed in reflected light at different
viewing angles.
7. A security paper according to at least one of claims 1 to 6, wherein
the integrated circuit is disposed between the layers having the optical effect and
the security paper.

8. A security paper according to at least one of claims 1 to 7, wherein
the energy supply for the integrated circuit is effected contactlessly via a cou-
pling element.
9. A security paper according to claim 8, wherein the coupling element
is part of the integrated circuit.
10. A security paper according to claim 8, wherein the coupling element
is disposed in a layer of the security element.
11. A security paper according to claim 10, c wherein the integrated circuit
is connected with the coupling element.
12. A security paper according to claim 10 or 11, wherein the security ele-
ment has at least one metallic layer in which the coupling element is formed.
13. A security paper according to claim 12, wherein the metallic layer is
separated from the layers producing the optical effect by an insulating layer.
14. A security paper according to claim 12, wherein the metallic layer is
at the same time one of the layers producing the optical effect.
15. A security paper according to at least one of claims 8 to 14, wherein
the coupling element is a folded dipole, a coil or an open dipole.
16. A security paper according to claim 15, wherein the folded dipole or
the coil has a metalized core zone.
17. A security paper according to at least one of claims 1 to 16, wherein
the integrated circuit is a memory chip or a microprocessor chip.
18. A security paper according to at least one of claims 1 to 17, wherein
the security element is a transfer element or a label disposed completely on the
surface of the security paper.

19. A security paper according to claim 18, wherein the security element
has the form of a strip.
20. A security paper according to at least one of claims 1 to 17, wherein
the security element is a security thread.
21. A security paper according to at least one of claims 8 to 19, wherein
the coupling element occupies an area of at least 20 square millimeters.
22. A security paper according to at least one of claims 1 to 21, wherein
the security element is so connected with the security paper that they cannot be
separated nondestructively.
A document of value with at least one multilayer security element having at least
one visually checkable optical effect, the security element being disposed com-
pletely on the surface of the document of value, characterized in that the security
element has at least one integrated circuit.
24. A document of value according to claim 23, wherein the document
of value is a passport, a bank note or a credit card.
25. A document of value according to claim 23 or 24, wherein the docu-
ment of value has a security paper according to at least one of claims 1 to 22.
26. A document of value according to at least one of claims 23 to 25, wherein
the document of value has a print, in particular an intaglio print, at least
overlapping with the security element.
27. A multilayer security element for application to a document of value, the security
element having at least one visually checkable optical effect, characterized in that
the security element has at least one integrated circuit.
28. A transfer material for applying a multilayer security element to a document of
value, the transfer material having a carrier layer on which the layer structure of

the security element is detachably prepared, and the security element having at
least one visually checkable optical effect, characterized in that the layer struc-
ture of the security element has at least one integrated circuit.
29. A transfer material according to claim 28, wherein the transfer mate-
rial has the following layer structure:
a carrier layer,
at least one layer producing the optical effect, and
at least one integrated circuit.
30. A transfer material according to claim 29, wherein the layer produc-
ing the optical effect is a printed layer containing optically variable pigments, in
particular interference-layer or liquid-crystal pigments.
31. A transfer material according to at least one of claims 28 to 30, wherein
the transfer material has the following layer structure:
a carrier layer,
a layer in which diffraction structures in the form of a relief structure are
present,
a metal layer in which a coupling element is formed,
an integrated circuit, and
a hot-melt adhesive layer.
32. A transfer material according to at least one of claims 28 to 30, wherein
the transfer material has the following layer structure:
a carrier layer,
a layer in which diffraction structures in the form of a relief structure are
present,
a reflecting layer permitting the diffraction structures to be observed in re-
flected light,
an insulating layer.
a metal layer in which a coupling element is formed,
an integrated circuit, and

a hot-melt adhesive layer.
33. A transfer material according to claim 31 or 32, wherein the inte-
grated circuit is connected with the coupling element via a conductive adhesive
layer.
34. A transfer material according to claim 33, wherein the conductive
adhesive layer is a conductive silver layer or an anisotropic conductive adhesive
layer.
35. A transfer material according to at least one of claims 28 to 34, wherein
the coupling element is a folded dipole, a coil or an open dipole.
36. A transfer material according to at least one of claims 28 to 35, wherein
the integrated circuit is a memory chip or a microprocessor chip.
37. A transfer material according to at least one of claims 29 to 34, wherein
the transfer layer of the transfer material is formed as a non-self-supporting
foil.
38. A method for producing a transfer material for applying a multilayer security
element to a document of value, the transfer material having a carrier layer on
which the layer structure of the security element is detachably prepared, and the
security element having at least one visually checkable optical effect, character-
ized in that at least one integrated circuit is incorporated into the layer structure
of the security element.
39. A method according to claim 38, wherein the following steps are carried out:
a) providing a carrier layer,
b) applying at least one layer producing an optical effect,
c) vapor-depositing a metallic layer, a coupling element being formed in the
metallic layer,
d) applying an integrated circuit.

40. A method according to claim 39, wherein before step c) a soluble ink
is printed on in the form of the coupling element and any further patterns or char-
acters, and that after step c) said ink is removed together with the metallic layer.
41. A method according to claim 39 or 40, wherein the integrated circuit
and the coupling element are interconnected via a conductive silver layer or an
anisotropic conductive adhesive layer.
42. A method according to at least one of claims 39 to 41, wherein in
step b) a layer is applied into which diffraction structures in the form of a relief
structure are then embossed.
43. A method according to claim 42, wherein in step c) a UV-curable lac-
quer layer is applied that is cured during the embossing operation.
44. A method according to claim 42 or 43, wherein in step b) a reflecting
layer is applied to the embossed layer at least in certain areas.
45. A method according to at least one of claims 39 to 41, wherein in
step b) at least a metallic and a dielectric layer or at least two dielectric layers
with different refractive indexes are applied, the layers cooperating so that differ-
ent visual impressions arise when viewed in reflected light at different viewing an-
gles.
46. A method according to at least one of claims 39 to 45, wherein an
insulating layer is disposed between the layers producing the optical effect and
the metal layer to be applied in step c).
47 A method according to at least one of claims 39 to 45, wherein - in a
step e) an adhesive layer, preferably a hot-melt adhesive layer, is applied.
48. A method for producing a document of value with a security element, character-
ized in that the layer structure of the transfer material according to at least one of
least one of claims 28 to 37 is transferred to the document of value in certain ar-
eas and the carrier layer is then removed.
The invention relates to a security paper for producing documents of value (1),
such as bank notes, certificates, etc., with at least one multilayer security element (2).
The security element is disposed at least partly on the surface of the security paper and
has at least one visually checkable optical effect (7) and at least one integrated circuit (8).

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Patent Number

226510

Indian Patent Application Number

IN/PCT/2002/01578/KOL

PG Journal Number

51/2008

Publication Date

19-Dec-2008

Grant Date

17-Dec-2008

Date of Filing

24-Dec-2002

Name of Patentee

GIESECKE & DEVRIENT GMBH

Applicant Address

PRINZREGENTENSTRASSE 159, 81677 MUNCHEN

Inventors:

#	Inventor's Name	Inventor's Address
1	HOFMAN LARS	ALOIS-STEINECKERSTRASSE 7, 85334 FREISING
2	LOESSL ZAHEDI MARTIN	WILHELM-DIEB-WEG 3, 81927 MUNCHEN
3	SCHNEIDER WALTER	STADLBERG 11, 83714 MIESBACH

PCT International Classification Number

B42D 15/00

PCT International Application Number

PCT/EP01/07652

PCT International Filing date

2001-07-04

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	100 32 128.3	2000-07-05	Germany