MXPA00010257A - Substrate which is made from paper and is provided with an integrated circuit - Google Patents

Abstract

The invention relates to a substrate (1) which is made from paper and is provided with at least one integrated circuit (3) which is produced from a semiconductive organic polymer. A semiconductive organic polymer of this nature, when used as the base material for the integrated circuit (3), leads to the possibility of directly producing the substrate (1) in the required thickness, to the need for support layers and/or protective layers being eliminated, and to the possibility of reducing the cost price of the substrate (1) compared to substrates which comprise an integrated circuit (3) of the silicon type.

Description

SUBSTRATE MADE OF PAPER AND PROVIDED WITH AN INTEGRATED CIRCUIT DESCRIPTIVE MEMORY The invention relates to a substrate made of paper and provided with at least one integrated circuit. A substrate of this nature is known from the German patent application DE-196 01 358, and is used in security documents and banknotes to protect against forgery and fraud. This known substrate comprises an integrated circuit that is incorporated in the substrate and contains predetermined data. The Cl is readable without the need for contact and binds to the substrate in a non-releasable manner. The Cl used in this substrate is a conventional Cl, that is, the well-known type of silicon. The dimensions of the originally produced chip are reduced by engraving or burnishing, so that the chip acquires the thickness that is desired to be incorporated into the paper mass. In order to avoid damage to the crystalline circuits, the Cl is reinforced with the help of a support layer, which also serves to place the Cl. In addition, the Cl is covered with a protective layer, chemically resistant. The lack of flexibility of this known silicon chip is a disadvantage when a substrate of this nature is used as security paper, for example in banknotes and identity documents. In addition, the extra layers to be included, as well as the additional processing step to produce the appropriate dimensions, lead to an additional increase in the cost price of a substrate of this nature. The object of the present invention is to provide a paper-based substrate for use in security documents, banknotes and the like, in which an integrated circuit is incorporated, whose substrate does not have the disadvantages mentioned above. According to the present invention, this object is achieved with a substrate of the aforementioned type in which the integrated circuit comprises a semiconductive organic polymer. This means an electronic circuit that is arranged in the polymer material and the contents of which are programmed in order to assign it a specific function. Polymer chips of this nature are highly flexible and therefore eminently suitable for use in security documents such as banknotes. Even the sharp ridges on the chip manufactured from an organic semiconductor polymer do not impede chip operation. In addition, polymeric Cls can be produced directly in the desired dimensions, in particular considering the thickness, and the costs of a chip of this nature are lower by about a factor of 10 than the current lower price for a chip of the type silicon. In the polymer chip, the non-conductive support on which the semiconductive polymer material is deposited substantially determines the thickness of the total integrated circuit. It is preferable to use a mechanically strong isolator: plastics with strong intramolecular and intermolecular interactions are preferably suitable for this purpose. By using a CI of this nature as a security mark on security paper and similar items, new and powerful means of protection are provided, because the production of those Cls is much more complicated for counterfeiters and generally exceeds by far their knowledge. and capabilities. In the context of this application, paper is understood to mean paper that is made from natural or synthetic fibers, as well as "paper" that can currently be produced from plastic films, whose paper is used for the production of paper. security, bank notes and the like. The integrated circuits can be in number one or more and can be adjusted as a function of the requirements. For example, in order to certify an operation, it is possible to incorporate two or more identical polymer chips, so that in the event that one of those chips fails the substrate and / or the final product that has been produced therefrom. It can still be used. Preferably, the organic polymer is selected from conjugated polymers, in particular from oligonumeric pentacene, poly (thienylene vinylene) or poly-3-alkylthiophene. A Cl that is produced from one of these materials is described by Brown et al. in Science, 270, pp. 972-974, 1995.

As will be understood by the skill person, the plastic Cl, used in the invention, comprises additional layers of different polymers apart from the semiconductive polymer layer. For example, the substrate can be produced from polyimide, on which polyaniline blocks are formed, which function as a source and drain. Above it, the semiconductive polymer layer is present, for example, comprising poly (thienylene vinylene). This layer is covered by an insulating layer, for example of polyvinylphenol, while a top layer of polyaniline is the uppermost layer, which is the gate. In one embodiment of the substrate according to the invention, the integrated circuit is readable without the need for contact, the data transmission being brought by an inductive or capacitive route, as is known in the prior art. In case of inductive reading, a coil is needed for the current supply, which must be connected in a conductive manner to the Cl, thus making it possible to read from a distance. In order to be able to read at a small distance it is necessary that the Cl contacts a conductor, in which this conductor together with the measuring device creates a capacity, with which the supply of current and reading become possible. According to another preferred embodiment of the substrate according to the invention, the substrate comprises a conductive safety fiber which is connected to the integrated circuit, whose conductive fiber serves as a direct contact or indirect contact for the emission and for supplying the current. In a preferred embodiment thereof, the security filament is metallized in order to provide the required electrical conductivity, except at the polymeric Cl position, where the metal deposition is interrupted. In the case of direct current supply, the metal must be accessible. Possible ways to provide this accessibility include a security filament that is incorporated into the substrate, as well as a security filament that is incorporated into the substrate and the metal parts of which are accessible through the so-called windows. Advantageously, one or more integrated circuits are part of the security fiber itself. The thickness of this security fiber can be adapted to the designed use of the substrate, for example in banknotes. For banknote paper, the thickness of the paper substrate normally lies on the scale of up to 100 μm. In this case, the thickness of the security fiber lies preferably in the range of 15-60% of the thickness of this substrate. If the paper substrate has a different thickness, such as for a cover of an identity document such as a passport, a minimum thickness of the security fiber of approximately 10 μm is applied. A thickness greater than 100 μm is relatively pointless for use in security paper. The preferred embodiment of a polymer Cl in the form of a security fiber provides an additional security feature that can be easily recognized by the public. The fiber comprising an integrated circuit may additionally comprise a number of other characteristics, such as an ink, fluorescent or phosphorescent material, luminescent material and printed indices. Conductive, organic polymers can also be used to supply the current to the chip, although in the case of direct contact the mechanical contact properties of these polymers currently still leave something to be desired. A single security fiber consisting of conductive polymers is proposed in European patent application EP-A-0,753,623. However, a fiber of this nature has only conductive properties. There are no semiconductor properties, and therefore it is not possible to apply and store a code in a manner that is comparable to a conductive polymer fiber in which an integrated circuit is incorporated. The security fiber comprising an integrated circuit according to the invention can be arranged in the usual way, for example being incorporated completely or integrated in the paper mass, in a window or being adhered to the surface of a document. If protection against attack of chemical materials is required, a chemically resistant, electrically non-conductive protective layer can be applied to the organic conductive polymers of the chip. The polymer chip does not have to be completely incorporated into the paper per se, as is the case for the silicon chip in the German patent application mentioned above. As an alternative, the polymeric Cl can also be disposed on the surface of the substrate, using customary techniques for adhering sheets, holograms, other optically active elements and the like. The integrated circuit can also advantageously be part of all types of optically active elements, such as plates, patches, holograms or quinegrams, which are arranged on or in the substrate as additional security features. As already described above in relation to a security fiber, according to a further preferred embodiment it is also possible to form optically active elements of this nature in such a way that two separate electrically conductive parts of said elements operate for emission and supply of current , both directly and capacitively. The conductive parts may consist of metal, conductive polymer or a combination thereof. For protection purposes, the integrated circuit may comprise a pre-programmed code, whose code is applied before the chip is incorporated into the substrate. Advantageously, the integrated circuit comprises a code of an intrinsic property of the substrate in which the circuit is incorporated. In the current state of the art, polymer Cl can be used only in one direction, that is, it can be written or programmed once. A preferred way to store a code in the Cl is to use techniques that are derived from cryptology. The authentic code is then stored in the Cl in an encrypted way, and it is impossible to decipher it without knowing the secret key. In this way, even if unwritten chips can be obtained legally, the secret key forms a powerful and virtually impenetrable barrier that prevents the counterfeiter from applying a message to security documents and issuing this message. The protection can be further improved if the optional partial programming of the chip is carried out after the Cl has become part of the security document, as will be explained in more detail below. The shape of the polymer chip is not critical. Currently, a dimension of approximately 1 mm for a rectangular shape represents the lower limit of a surface dimension if a reasonable number of bits is going to be stored in the Cl. A rectangular 4 mm by 6 mm Cl currently contains approximately 48 bits , that is 2 bits / mm2. The ratio of the surface dimensions for a polymer chip (ie, length to width) should preferably not exceed 10: 1, due to the undesirable resultant accumulation of the chip with given larger ratios. The small dimensions of a Cl offer the possibility of covering the chip with additional features that are commonly used in the prior art. The dimensions of such additional features are generally large compared to the dimensions of polymeric Cl. In this way even large Cls, with enough memory capacity to store large amounts of data, can be used without affecting the appearance of security paper. If a combination of a chip with another security mark is placed on the security paper, it is necessary to ensure that the reading and current supply to the chip are not adversely affected by an additional security feature of this nature. The substrate comprising a polymer Cl according to the invention is used as a security paper in, for example, banknotes, passports, identity cards and other security documents, such as titles. The development of a cheap integrated circuit of this nature offers a number of new possibilities to avoid falsification of security documents, starting with a completely new type of electronic (electronic bar codes) on security paper. Examples of the use of a CI as a security feature in a document that will be described are the various possibilities for a banknote, but similar possibilities exist for other types of security documents, such as passports, identity cards and the like. A first possibility refers to the use of a Cl completely preprogrammed in the substrate made of paper. The CI contains one or more codes, if desired in an encrypted form, in relation to the banknote. This information may include the value, the country, the place and / or production time, number and the like. For a specific value of the banknote, the information on each chip is substantially identical, ie value, country and normally the manufacturer and / or paper printer, and partially different, ie, production time, production numbers and some Sometimes manufacturer and / or paper printer. More specific protection is obtained with a chip that is partially programmed with a unique code (first code) and a second additional code. This second code is an encrypted translation of the first code. The encryption is carried out using a first key. In the case of verification, the second code is read and the encrypted relation to the first code is verified using a second key. The second code can be applied to the chip before or after the chip has been arranged on the substrate. An encryption system of this nature is described, by way of example, in WO-A-97/24699. In this known system, an intrinsic property of the object is encoded, encrypted and encrypted. For bank notes, the surface properties are taken in a special location, encoded, encrypted and stored as a printed pattern on the banknote. In the case of verification, the printed pattern and the surface property are compared to one another using a second key. Many other properties, as well as properties arbitrarily distributed in the substrate, are used in the prior art for the protection of security documents, cf., inter alia, WO-A-91/19614 (fiber address), GB- A-230,407 (reflective flakes), US-A-4,218,764 (particles or magnetic fibers) and WO-A-87/01845 (conductive fibers). In all these cases, arbitrary and therefore unique properties of a document are used for verification. Hence, there has not been a suitable chip available for use on paper substrates in order to store the code (encrypted) and consequently a coded property was always stored in another way, for example on the outside of the document itself, or it was printed in or on the document or it was registered in a magnetic way in it. The polymeric chip that is used in the substrate according to the invention makes it technically possible to use and store those protection features within the document. The fluorescence properties of fluorescent fibers arbitrarily distributed in a predetermined area of the banknote can be a suitable property. However, any other property that can be measured and that is arbitrarily distributed on or on paper can also be used. One condition is that the property used must be stable throughout the life cycle of the document, which means that any property that depends a lot on the consequences of use, such as soiling, contamination, wrinkles and the like, is in principle inadequate . The coordinates of the relevant part of the bank note where the arbitrary property is determined and, if necessary, the orientation in which the surface should be examined, can also be stored on the chip. In this way, when the banknote is verified, a specific parameter is measured along a predetermined path, or an image of the entire banknote is taken, but the evaluation is carried out only using the data that is they find in the precoded coordinates. The result of this measurement is compared to the stored code, which also refers to the same property in the same location. Based on this comparison, which can be optionally encrypted, a rejection or acceptance signal is generated. The substrate with a polymeric Cl according to the invention can also comprise usual security features, such as watermarks, security fibers, optically active elements and special chemicals, microprints, etc., using standard techniques to determine those characteristics. The invention also relates to a security fiber or optically active element comprising an integrated circuit manufactured from a semiconductive organic polymer. The following example illustrates the invention. In this case, specific fluorescent properties are used in a specific part of the document as an example. Many banknotes are supplied with a number of highly fluorescent fibers that emit different colors of light. These fibers are distributed arbitrarily throughout the document. The local fluorescence of various types of fibers at a predetermined location can be digitally encoded and stored on the chip, optionally in encrypted form, at the time the document is produced, i.e. during the papermaking phase or during the printing phase of the document. In the case of verification, the area in question is read again using the coordinates and orientation that are stored on the chip, and the results are compared with each other, followed by rejection or acceptance. The coordinates and orientation will generally differ for each separate banknote, with the result that the verification is completely unique to the document, because the property and arbitrary coordinates are unique to that document. In this way, the chip of each separate banknote contains a unique code which, as it were, represents a fingerprint of a specific part of the banknote in question. The intrinsic property code can be stored either in encrypted or unencrypted form. As already mentioned above, the use of the substrate according to the invention is not limited to banknotes. For other uses, such as passports and identity documents, part of a biometric property of the legal owner can be used to generate a digital code that is then stored in the CI of the document. One such example could be an encoded part of a digitized photograph of the legal owner, the part to be digitized being determined by encoded parameters that are unique to each document. Completely as for the example given above, verification of the document requires that the stored code of the photograph and the code currently read coincide with each other. Other biometric parameters may also be used, such as fingerprints or parts thereof, which are then stored in encoded form on the polymer chip. Here, too, it is necessary that the coded, stored characteristic be stable. To further illustrate the invention, reference is made to the appended drawings, in which: Figure 1 shows a plan diagram view of a modality of a banknote according to the invention. Figure 2 shows a cross section through the banknote illustrated in Figure 1, along the line l-l. Figure 3 shows a plan diagram view of another embodiment of a banknote according to the invention. Figure 4 shows an enlarged illustration of an optically active element that is used in the banknote according to Figure 3. Figure 5 shows a cross section through the optically active element illustrated in Figure 4. Figure 6 shows a cross section through yet another embodiment of a banknote according to the invention. Figure 7 shows a further embodiment of a security fiber with polymeric chip. Figure 8 shows another embodiment of an optically active element with a polymeric chip. Figure 9 shows a combination of a safety fiber and an optically active element; and Figure 10 shows still another embodiment of a security fiber according to the invention, in cross section. It should be noted that, in the figures discussed below, identical components are denoted by identical reference numbers. Figure 1 shows a banknote 1 made of paper. The banknote 1 comprises a security fiber 2 containing a chip 3 made fa semiconductive organic polymer and conductive parts 4, for example, metallized. In addition, the banknote 1 comprises a second chip 3 ', which is likewise manufactured fa semiconductive organic polymer. As can be seen fthe cross section according to Figure 2, the security fiber 2 is disposed on the paper 5, while the second polymer chip 3 'is embedded in the paper mass 5. The chip 3' embedded makes contact with a conductor or coil as to provide the required current and emission. Figure 3 shows another embodiment of a banknote 1, in which the security fiber 2, again containing a polymeric chip and conductive parts 4, is incorporated in the paper mass. Sections of the conductive parts 4 are accessible through windows 6 in order to make direct electrical contact, if desired. The banknote 1 illustrated in Figure 3 also comprises a second chip 3 ', which in this case is located under an optically active element 7. The optically active element 7 comprises conductive parts 8 which are separated by a strip 9 which it is insulating, that is, not conductive. The 3 'chip can be read and supplied with energy through the conductive parts 8, either directly or fa distance through capacitive coupling. The conductive part may be covered by a chemically inert layer, if the emission is done capacitively. If direct contact is required, a part of the conduit and the entire part 9 can be covered in such a way that the Cl and the conductor are protected (with a non-conductive material) while other parts of the conductor are still accessible for direct contact. Figure 4 shows an enlarged view of the optical element 7 with the chip 3 ', while Figure 5 is a cross section through an optical element 7 of this nature. Figure 6 shows a further embodiment of a security fiber 2 with a chip made fsemiconductive organic polymer 3 and conductive parts 4, which are applied to the paper 5. In this embodiment, the polymer chip and the sections of the Conductive parts 4 of the security fiber 2 are protected by a layer 10 of an electrically non-conductive, chemically resistant material. The protective layer 10 can cover the entire fiber, if the capacitive coupling is used. Figure 7 shows yet another embodiment of a security fiber according to the invention, in which the chip 3 is not part of the security fiber itself, but rather is placed next to it. The conductive parts 4 of the security fiber 2 are electrically isolated fone another by means of the insulating block 4. The chip 3 is connected to the relevant conductive parts 4 of the security fiber through electrical conductors 12. One embodiment thereof The type for an optically active element is illustrated in Figure 8. The electrical conductors 12 provide the electrical contact between the conductive parts 8 of the optically active element and the polymeric chip 3 '. Figure 9 shows a combination of a security fiber 2 with optically active element 7, the metal parts 4 of the security fiber 2 make electrical contact with the metal parts 8 of the optically active element 7. A chip manufactured forganic semiconductive material 3 'is situated below the optically active element 7. Figure 10 illustrates yet another embodiment of a security fiber according to the invention. In this modality, the security fiber is composed of a chip 3 and conductive parts 13, which are manufactured from a conductive polymer. The security fiber is disposed on the paper 5. The polymer chip 13 is protected with a layer 10 of chemically resistant material, which also covers (sections of) the conductive polymer 13. In order to ensure a very good energy supply and emission, metal blocks 14 are arranged adjacent to the layer 10 of insulating material, whose metal blocks 14 are electrically connected to the organic conductive polymers 13. In case of a system using capacitive coupling an additional protective layer can be applied on the metal parts 14 and the chemically resistant layer 10. ^^ * g * ^^

Claims (17)

NOVELTY OF THE INVENTION CLAIMS

1. - A substrate that is made of paper and is provided with at least one integrated circuit, characterized in that the integrated circuit is flexible and comprises a semiconductive organic polymer.

2. The substrate according to claim 1, further characterized in that the organic polymer is selected from conjugated polymers.

3. The substrate according to claim 1 or 2, further characterized in that the organic polymer is selected from oligomeric pentacene, poly (thienylene vinylene) or poly-3-alkylthiophene.

4. The substrate according to one of the preceding claims, further characterized in that the integrated circuit is a non-contactable read that can be read in an inductive and capacitive manner.

5. The substrate according to one of the preceding claims 1-3, further characterized in that the substrate comprises a conductive safety fiber (2) that is connected to the circuit or integrated circuits (3), whose safety fiber (2) It serves as a contact for emission operations and for power supply.

6. The substrate according to claim 5, further characterized in that the integrated circuit (3) is part of the security fiber (2).

7. The substrate according to claim 4 or 5, further characterized in that the security fiber (2) has a thickness that lies on the scale of 5-60% of the thickness of the substrate.

8. The substrate according to one of the preceding claims 1-4, further characterized in that the integrated circuit (3 ') is part of an optically active element (7), such as a sheet, hologram or quinegram.

9. The substrate according to one of the preceding claims, further characterized in that the integrated circuit comprises a pre-programmed code that is applied before incorporating the circuit in the substrate.

10. The substrate according to one of the preceding claims, further characterized in that the integrated circuit comprises a code of an intrinsic property of the substrate, whose code, after the substrate has been produced, is arranged in the integrated circuit.

11. A substrate according to claim 9 or 10, further characterized in that the code is an encrypted code.

12. The substrate according to one of the preceding claims, further characterized in that the substrate comprises additional security features.

13. The substrate according to claim 12, further characterized in that an additional security feature is selected from an ink, fluorescent material, luminescent material or phosphorescent material.

14. A security paper comprising a substrate according to one of the preceding claims.

15. A security document comprising a substrate according to one of the preceding claims 1-13.

16. A security fiber (2) comprising an insulating support (5) carrying a flexible integrated circuit (3) comprising a semiconductive organic polymer, provided with electrical contacts for the integrated circuit.

17. An optically active element (7) comprising a flexible integrated circuit (3 ') comprising a semiconductive organic polymer, provided with electrical contacts (8) for the integrated circuit. z & -fc-,? i.