EP0680411B2 - Document with doped optical safety mark, stratified composite paper for producing the same and device for checking the authenticity of the document - Google Patents

Abstract

PCT No. PCT/AT93/00176 Sec. 371 Date Jul. 13, 1995 Sec. 102(e) Date Jul. 13, 1995 PCT Filed Nov. 17, 1993 PCT Pub. No. WO94/11203 PCT Pub. Date May 26, 1994A document, for example a bank note, a check, a credit card, an identification document or a ticket, bears an optical safety mark in the form of a light-reflecting and light-diffracting and/or refracting layer, for example a hologram, an interference layer, a (computer-generated) refracting structure, located on at least parts of the document. The optical safety mark is arranged in a sandwich structure which is fixed to the document by means of an adhesive layer and if required has one or several transparent layers arranged in the sandwich structure. The adhesive layer and/or transparent layer in the sandwich structure is doped with at least one luminescent substance.

Description

The invention relates to a document, e.g. Banknote, check, credit card, ID card or ticket, which is an optical Security feature in the form of a light reflecting and diffractive provided at least in some areas and / or refractive layer, e.g. a hologram, an interference layer, a (computer-generated) Diffraction structure or the like has, wherein the optical security feature is provided with doping material and in a film structure is present, which is attached to the document by means of an adhesive layer and, if appropriate has at least one transparent layer in the film structure.

Furthermore, the invention is concerned with a film structure, for the production of such documents, with a carrier film and a transfer layer which can be detached therefrom and which is at least the embossed optical security feature forming, light reflecting as well as diffractive and / or refractive layer, in particular as an embossing film, is preferably formed as a hot stamping film, and on the side of the reflective side facing away from the carrier film Layer has an adhesive layer, at least one transparent layer being arranged in the film structure can.

Documents of the type mentioned are known for example from CH-PS 661 602. To make such Embossing foils serving as documents of value, in particular hot embossing foils, are e.g. described in DE 34 22 910 C1.

The known documents or embossing foils have an optical diffraction effect as a security feature all against color copy structure, such diffraction optically effective, i.e. Light reflecting, Diffractive and / or refractive structures have the basic advantage that they are with the unarmed eye recognized, but can also be read by machine. Typical structures applied in particular to banknotes include Kinegrams and pixelgrams. The falsification of such structures is very difficult, but is still in preparation all feasible if it is possible to expose the correspondingly structured surface and galvanically to take impressions or to copy phototechnically.

In order to make documents tamper-proof, the use of luminescent layers in the documents proposed. For example, DE-OS 37 41 179 discloses the use of two security features, namely firstly, a relief embossed in paper and thus already palpable, and secondly a luminescent relief as a second security feature Substances on the peaks or in the valleys of the relief. In the subject of DE-OS 37 41 179 can a transfer belt can be used, the layers of which are applied to the document by means of an adhesive layer can be, the transfer ribbon, however, a color layer of a luminescent substance in addition to this luminescent layer can contain a color pigment layer.

DE-OS 39 06 695 shows the embedding of a tape serving as a security element in a document. The Band consists of a translucent plastic film, which with characters or patterns in the form of recesses is provided, with additionally luminescent substances in areas that are identical to the recesses are arranged. There are therefore two security elements here too, namely one the signs and patterns and also the luminescent substances.

Finally, according to DE-PS 27 54 267 two security features are available for documents, from which has a luminescent properties. In contrast to the brilliant, superficial optical features however, threads, sheets and fibers are incorporated into the paper.

The known state of the art can thus be summarized in that it is known luminescent substances on the one hand in the area of application of the non-optical features by (partial) printing, To apply coating, embossing or also with transfer ribbon transfer and on the other hand in the area of application optical characteristics (e.g. reflective grid structure with a number of lines of about 1000 / mm and line depth of about 100 nm) to be used to secure documents with protective coatings that cover the surface.

In previous approaches to machine detection of optical features, the focus was on the itself obvious optical reading of the lattice structures or information or image content concentrated, but with that not only is there a considerable amount of technical effort involved in reading the multidimensional information, but also the effects of damage, such as occurs in banknotes in circulation and Destruction of the structures and thus lead to the disadvantageous illegibility of the feature authenticity, accepted. Corresponding falsifications of the impression of the optical feature would not be recognized with such a detection can be.

The object of the invention is now the authenticity detection of the optical feature applied to a document by verifying the authenticity independent of an existing (forged) hologram lattice structure, for example to be able to perform and thereby design the optical feature so that a reliable machine detection guaranteed in the high-speed range (10 m / sec) without incorrect readings and resulting rejections can be. Documents should therefore only be rejected as suspicious if an imitation of the optical feature is present or this is missing entirely. In contrast, documents with damaged optical Features in the sorting process are controlled in a storage compartment for unusable documents and therefore none considerable effort in the form of manual processing, like this for Rejection is necessary.

This problem is solved with a document of the type mentioned in Surprisingly simple way if, according to the invention, the adhesive layer at least one luminescent substance is doped. It is also possible that different luminescent substances are contained in the adhesive layer.

The inventive design of the document, on the one hand enables a simple and therefore extremely inexpensive authenticity measurement arrangement and on the other hand a completely negligible rejection rate at the machine processing of the documents achieved. In addition, there is Advantage that a high-quality professional made with the intention of deception Falsification of the structure of the optical feature is nevertheless machine-recognizable and in the case of counterfeiting, this during the sorting process or by one trained cashier can be eliminated or recognized.

The incorporation of the luminescent substances into the adhesive layer (Doping of the adhesive layer) has the advantage that in the case of a Attempted manipulation of the optical security feature, e.g. trying one Lifting or peeling, still parts of the adhesive layer and thus the Doping material stuck to the document. Furthermore, the adhesive layer. with its thickness of about 6 µm, it is the thickest layer in the film structure. Many Luminescent materials, such as rare earths, are more inorganic Natural and must be milled, with their particle sizes below 5 µm Significantly lose or lose lighting properties. Many of the for circulating Banknotes suitable luminescent pigments with sufficient aging, UV and Chemical resistance can only be produced with particle sizes above about 5 µm. Would you now such materials in a (retrofitted) on Include document surface protective layer, this would be among others Disadvantages also to reduce the brilliance and to a production technology disadvantageous selective thickening of the document or the stack of paper occasion give. Due to the technologically related process control of the Adhesive coating can ensure that the luminescent material in constant layer thickness or concentration is incorporated in the optical feature. The doping material is underneath the metallic reflection layer Protected against UV radiation. Luminescent substances which are preferred normal daylight, not using a UV lamp or other electromagnetic radiation corresponding energy can be determined. The addition of luminescent substances in the adhesive layer has an opposite for example, structures which have a purely optical diffraction effect have the advantage that Security feature can still be determined when the document or Foil structure, e.g. mechanical, badly damaged. Unless it's a forger the diffractive optical structure should succeed on a fake one To transfer the document of value would still be the forgery because of the missing luminescent properties on the fake, but with the original diffractive structure provided document.

The admixture of luminescent substances provided according to the invention to the adhesive layer in the film structure can practically without additional effort in the usual production of the documents or the film structure can be realized and thus offers a very significant increase in the security effect without noticeable additional costs. If necessary, from security or production engineering considerations the application of the doped adhesive layer also either retrospectively on the prefabricated optical present on carrier film Security feature or in advance on the carrier material, especially paper, at Paper or document manufacturers take place.

If, as is possible according to the invention, the luminescent Substances only partially in the adhesive layer, preferably in one certain, preferably machine-readable patterns are provided additional securing options, because then not just a general admixture of the luminescent substances to the adhesive layer is sufficient, but additionally that luminescent substances have to be introduced in a very specific way, which is only possible using special machines.

Luminescent substances are expediently fluorescent or phosphorescent, the decision to use fluorescent or phosphorescent substances of the respective purpose depends, but possibly there is also the possibility of fluorescent and use phosphorescent substances together, optionally each of the To provide substances in a certain pattern.

As a particularly suitable luminescent for the purposes of the invention Substances have narrow-band fluorescent substances, e.g. from the Group of rare earths proven. Also fluorescent substances are very closely adjacent emission compared to the excitation wavelength and those with same emission wavelength can be used advantageously. The presence or The absence of substances of this type can be known from those known per se Determine measuring devices with great accuracy, already using luminescent substances that differ in terms of their luminescent properties Deviate slightly from original fabrics, can be safely determined, above all because the radiation devices used in checking the value documents etc. can be adapted exactly to the substances to be tested.

In a film structure according to the invention, it is advantageous if the Adhesive layer is formed by a hot melt adhesive, which is then the usual Application method for hot stamping foils easily a reliable adhesion generated.

The transparent layer in the film structure consists of a film structure expediently according to the invention from one of the known Transparent coatings.

To ensure that the light forming the optical security feature reflective layer also reliably reflects the light, is according to the invention provided that the reflective layer of one, preferably by Evaporating in a thin metal layer, e.g. one Aluminum layer is formed.

In a film structure according to the invention it is finally provided that between the carrier film and the transfer layer, a release layer, e.g. a Wax layer, is arranged.

Further features, details and advantages of the invention result from the following description of preferred exemplary embodiments with reference to the Drawing.

Fig. 1 schematisch ein Wertdokument in Form einer modifizierten österreichischen Banknote im Wert von ATS 5000,--, die erfindungsgemäße Merkmale besitzt,

Fig. 2 einen Schnitt nach Linie II-II durch das Wertdokument gemäß Fig. 1, in vergrößertem Maßstab, die

Fig. 3 schematisch im Schnitt eine Ausführungsform einer Prägefolie,

Show it:

1 schematically shows a document of value in the form of a modified Austrian banknote worth ATS 5000, - which has the features according to the invention,

Fig. 2 shows a section along line II-II through the value document of FIG. 1, on an enlarged scale, the

3 shows schematically in section an embodiment of an embossing film,

1 has banknote paper as the carrier 1, however In the case of differently designed value documents, the carrier can also use a synthetic one Paper, a plastic film or, in the case of a credit card, a plastic card his. A plastic card can be embossed on its front, for example Letters bear the name of the owner and an identification number. The Value document 1 has a local security feature, which in a film structure, which can be a layer composite 4 is present, which is shown in FIGS. 3 and 4 is shown where it is formed as an embossing film.

There is an optical security feature in the layer composite 4, namely a light reflective and diffractive and / or refractive structure present, the For example, is formed by a thin metal layer 5, which in the Embodiment of FIGS. 1 and 2 between one drawn as the top one transparent layer 6 embedded in the layer composite 4 and an adhesive layer 7 is. The adhesive layer 7 serves to fix the layer composite 4 on the Surface of the document 1. The transparent layer 6 in the layer composite 4, the is drawn as the top layer in the exemplary embodiment (FIG. 2), which covers that of the Metal layer 5 formed, diffraction-optical structure and difficult thus a decrease in the structure attempted forgery.

The peculiarity of the document of value according to the invention is now too see that luminescent substances are present in the adhesive layer 7. Such substances can also be known in the transparent layer 6 be provided. You can, as in the embodiment of FIG. 1, only in areas, namely in area 8, where in the exemplary embodiment Head representation is located. A preparation can be used as a substance narrow band fluorescent rare earths are used.

The security feature in the document of value according to FIG. 1 thus exists not only from the diffraction optically effective, possibly specially shaped structure in the metal layer 5, but additionally in the layer composite 4 of the Areas with luminescent properties are present, these properties are also determined mechanically by readers and can be checked.

Basically, the attachment of the optical security feature with luminescent properties according to the invention on documents of value in take place in any way, for example also in that the layers of Layer composite 4 are applied in succession.

However, it is much more expedient if the layer composite 4, as in Fig. 3 schematically shown, is applied to a carrier film 9 and as Stamping foil, advantageously as a hot stamping foil, is used. Such Hot stamping foils can, for example, as described in DE 34 22 910 C1, be constructed. They have a carrier film 9 on which with the interposition a release layer 10 made of wax which is designated as a whole by 11 Transfer position is arranged. When applying the layer composite 4 on the Document 1 will be the transfer layer 11 with its backing away from the carrier film 9 Surface pressed on the document 1, under the action of heat, on which it then adheres by means of the adhesive layer 12. The carrier film 9 becomes immediate then removed, which is facilitated by the wax release layer 10.

In the stamping foils shown in FIG. 3, the transfer layer 11 consists of an adhesive layer 12 and a transparent layer 13, in the layer composite. There is a reflective layer between the adhesive layer and the transparent layer Layer 15 made of metal arranged, at least in some areas, an optical diffraction effective, i.e. Has light refractive or diffractive structure 14. In the Production of the layer composite 4 (the embossing foils) is in turn according to DE 34 22 910 C1, first the release layer 10 on the carrier film 9 0 and then the transparent layer 13 applied in the layer composite. The ones from Backing film 9 facing surface of the transparent layer 13 is with the desired refractive or diffractive structure 14 introduced. thereto the structured surface of the transparent layer then becomes Generation of the reflective layer 15 metallized, for example by Evaporation of aluminum in a vacuum. The layer composite 4 is then through Application of the adhesive layer 12 completed.

A simplified embodiment for subordinate ones would also be conceivable Applications in which the transfer layer 11 consists of only one layer, which fulfills both the optical and the adhesive function.

3, the adhesive layer is in areas 16 12 luminescent substances available. The reflective layer 15 made of metal may be interrupted in these areas. However, they are also embodiments possible, in which the carrier 1 is transparent in order to test for Presence of the luminescent substances from the underside of the carrier to be able to make, especially if the carrier 1 is a plastic card. For example, in the embodiment of FIG. 1, the luminescent ones Regions 16 may also be present outside the metal layer 5.

Of course, the luminescent substances can also be used in the entire adhesive layer 12 may be present, which is for certain security purposes is quite sufficient. It should also be noted that as a luminescent Substances a wide variety of substances, for example fluorescent and phosphorescent substances, also used in different mixtures can be.

The group of organic luminous pigments includes an almost colorless, typical at 545 nm fluorescent benzoxazine derivative from the company Riedel-de Haen is sold under the name Lumilux CD 304.

The range of fluorescent substances in the form of solutions is one of them heterocyclic thioxanthene dye available from Bayer under the Trade name Macrolexfluorescence Red GG is sold.

Rare earths are phosphorescent and have very typical absorption and Emission spectra with narrow-band emission lines. As examples are Scandium, yttrium and the lanthanides to call the europium.

By appropriate mixture of luminescent substances or mixture With absorbent materials, doping materials are available that are visible Do not luminesce the area. Different fabrics are used for this absorption lines of one with the emission lines of the other in the cover visible area.

Also fluorescent substances with very closely adjacent emission known to the excitation wavelength. The represents a special case Resonance fluorescence, in which the absorption is equal to the emission line.

There are also luminescent materials in the form of organic semiconductors The basis of conjugated polymers (carbon chains in which double and Alternate single bonds) known as poly-p-phenylene-vinylene, whereby by Applying an electrical voltage stimulating electroluminescence which is used especially for static or quasi-static tests can be.

Adhesives that contain luminescent substances can have the following formulations, for example: Example 1 (numerical values in parts by weight) methyl ethyl ketone 250 toluene 395 ethyl alcohol 150 Vinyl chloride-vinyl acetate copolymer (mp:> 65 ° C) 110 Unsaturated polyester resin (mp: 100 ° C) 30 Wetting agent (40% in butyl acetate) (high molecular polymer) 10 Filler (SiO ₂ ) 5 Luminous pigment (type: Lumilux C, <5 µ; Riedel-de Haen) 50 Example 2 (figures in parts by weight) acetone 180 toluene 70 ethyl alcohol 380 Methyl butyl methacrylate (Tg = 80 ° C) 60 Ethyl methacrylate (Tg = 63 ° C) 50 Butyl / methyl methacrylate copolymer (40% in xylene) (Tg = 78 ° C) 180 Wetting agent (40% in butyl acetate) (high molecular polymer) 10 Filler (SiO ₂ ) 10 Luminous pigment (type: Lumilux C, <5 µ; Riedel-de Haen) 60

Claims (17)

1. A document, e.g. bank note, cheque, credit card, identity card or ticket, which has an optical security feature in the form of a layer, e.g. a hologram, an interference layer, a (computer generated) diffraction structure or the like, which deflects and diffracts and/or splits light and which is provided at least in certain regions , the optical security feature being present in a film structure which is secured to the document by means of an adhesive layer and optionally has one or more transparent layers in the film structure, characterised in that the adhesive layer (7, 12) is endowed with at least one luminescent substance.
2. The document according to Claim 1, characterised in that different luminescent substances are contained in the adhesive layer (7, 12).
3. The document according to Claim 1 or 2, characterised in that the luminescent substances are provided only in certain regions in the adhesive layer (7, 12).
4. The document according to Claim 3, characterised in that the luminescent substances are provided in the adhesive layer (7, 12) in a predetermined, preferable machine-readable pattern (8, 16').
5. The document according to one of the preceding claims, characterised in that the luminescent substances are fluorescent or phosphorescent substances or mixtures of such substances, the fluorescent substances being optionally arranged in a pattern which is different to the pattern in which the phosphorescent substances are arranged.
6. The document according to Claim 5, characterised in that narrow-band fluorescent rare earths are used as luminescent substances.
7. A film structure for manufacturing a valuable document as claimed in one of Claims 1 to 6, including a carrier film and a transfer film which may be separated therefrom and which at least has the layer which constitutes the optical security feature and reflects and refracts and/or splits light and which is constructed in particular as an embossed film, preferably a hot embossed film, and an adhesive layer on the side of the reflective layer directed away from the carrier film, whereby a transparent layer can be arranged in the film structure, preferably between the reflective layer and carrier film, characterised in that luminescent substances are contained in the adhesive layer (12).
8. The film structure according to Claim 7, characterised in that different luminescent substances are contained in the adhesive layer (12).
9. The film structure according to Claim 7 or 8, characterised in that the luminescent substances are provided only in certain regions in the adhesive layer (12).
10. The film structure according to Claim 9, characterised in that the luminescent substances are provided in the adhesive layer (12) in a predetermined, preferably machine-readable pattern.
11. The film structure according to one of Claims 7 to 10, characterised in that the luminescent substances in the adhesive layer (12) are fluorescent or phosphorescent substances or mixtures of such substances, the fluorescent substances optionally being arranged in a pattern which is different to the pattern in which the phosphorescent substances are arranged.
12. The film structure according to Claim 11, characterised in that narrow-band fluorescent rare earths are used as luminescent substances.
13. The film structure according to one of Claims 7 to 12, characterised in that the adhesive layer (12) is constituted by a melt adhesive.
14. The film structure according to one of Claims 7 to 13, characterised in that the transparent layer (13) is a layer of transparent lacquer.
15. The film structure according to one of Claims 7 to 14, characterised in that the reflective layer (15) is constituted by a thin metal layer, preferably formed by vacuum coating.
16. The film structure according to one of Claims 7 to 15, characterised in that a release layer (10), e.g. a wax layer, is arranged between the carrier film (9) and the transfer film (11).
17. A method of checking a document in accordance with one of Claims 1 to 6, characterised in that the luminescent substances present on the document are excited from at least one source and the emission of the excited luminescent substances is measured in at least one receiver, whereby, for instance, photodiodes, photomultipliers, CCD arrays are used as the receiver and, for instance, a laser tube, laser diodes, light-emitting diodes, fluorescent tubes, halogen lamps, X-ray tubes, electron radiation tubes and radioactive emitters are used as the source.

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