EP1567364B1 - Safety element and method for producing said element - Google Patents

Abstract

The security element (2), for protection against forgery e.g. of a card (1) with a chip (11), has a refraction pattern (3) which is visible in zones as a holograph effect. The security element has a carrier and a substrate with a surface structure towards the carrier which has at least a partial optical refraction effect. An adhesive layer bonds the carrier and substrate. The security element (2), for protection against forgery e.g. of a card (1) with a chip (11), has a refraction pattern (3) which is visible in zones as a holograph effect. The security element has a carrier and a substrate with a surface structure towards the carrier which has at least a partial optical refraction effect. An adhesive layer between the carrier and substrate fills the space between them at least partially, coated indirectly with a reflection layer at the surface structures.

Description

The invention relates to a security element and a security paper and a document of value with such a security element, which has partially filled with adhesive, diffraction-optically effective surface structures. Furthermore, the invention relates to a method for producing the security element.

For the purposes of the present invention, value documents are in particular banknotes, check forms, shares, passports, passports, credit cards, air tickets and other documents and documents as well as labels, seals, packaging and other elements for product assurance. For example, unprinted security paper and other unprinted value document substrates come into consideration as semifinished products for the production of the aforementioned value documents.

In the manufacture of such value documents and security papers, it is particularly important to take precautions against falsification and / or measures to establish the authenticity. In addition to the features that can be recognized or used in particular in the examination by machine, there are also features that can be recognized by anyone without technical aids and without special expertise as an authenticity feature.

In order to increase the optical conspicuity of a security element, the security elements are often equipped with diffraction structures, such as conventional holograms, kinegrams, pixelgrams, etc.

The protection against counterfeiting of these elements is based on the viewing angle-dependent color play, which these elements show. Such security films are often applied in the form of strips or labels on the surface of valuables.

The diffraction structures are usually produced by converting the diffraction structures into a relief structure which is subsequently used as an embossing stamp. The embossing is usually carried out in a thermoplastic layer or a curable during the embossing lacquer or resin layer. In order to recognize the diffraction structures in the finished product in reflection, these layers are provided before or usually after the embossing process with a reflective layer. In the case of opaque security elements, this is a thin metal layer, with transparent security elements a layer of dielectric, such as, for example, in US Pat DE 41 30 896 A1 described.

All these known security elements have in common that the embossed structures are visually perceptible to a viewer only when using one or even several additional reflection layers. The more layers that have to be processed, the more costly and time-consuming the production is.

The stamp can also be used only for the respective job. In particular, in the case of mass-produced articles, such as holograms, variable or even individualized diffraction structures can therefore only be provided if a correspondingly high number of stamping dies is produced, so that the additional costs are distributed among as many final products as possible. For small runs or productions that are to be provided with different diffraction structures, the production costs are therefore too high.

From the U.S. Patent 4,921,319 Further, a relief hologram with a non-metallic transparent surface is known, which is fixed to a substrate. The surface structures are facing the substrate. In order to keep the surface structures spaced from the substrate and thereby provide an air layer between the hologram and the substrate, spacers are provided. The covered by the spacer surface should be kept as small as possible. The spacers should be transparent.

The US patent US 5,591,527 relates to optical security elements and methods for their production. The security elements comprise a first layer having a structured surface, which has a multiplicity of geometric depressions, a transparent adhesive layer adjoining it in regions and filling the recesses, a second layer adjoining the adhesive layer, and a release layer. The release layer only contacts the tips of the structured surface and is intended to keep the wells of the structured surface spaced from the second layer.

The invention is therefore based on the object to provide a security element, transfer element, security paper, value document and a method for their preparation. The method is intended to enable low-cost production in an economical manner, in particular even for small runs or varying information, without the forgery-proof security of the security element, transfer element, security paper and value document according to the invention being reduced.

The solution to these problems arises from the independent claims. Further developments are the subject of dependent claims.

According to the invention, the security element has a carrier and a substrate with diffractive optical surface structures, wherein the surface structures of the substrate surface facing the carrier. Between the carrier and the substrate is a partially present adhesive layer which fills the surface structures at least completely. At least some of the surface structures not filled with the adhesive layer are not directly coated with a reflective layer or another liquid or solid layer, as is absolutely necessary in contrast to the prior art. "Immediately coated" in the sense of the invention means that, for example, the reflection layer and the surface structures are not spaced apart from each other and the reflection layer comes to rest directly on the surface structures. Contrary to the usual expectations, the surface structures not filled with adhesive are clearly visible as patterns that can be perceived as diffraction-optical, without having to use an additional reflection layer. Without being bound by this explanation, the surface structures not filled with adhesive are presumably at a distance from the carrier, so that air is trapped here. The difference in refractive indices Thus, air and the material containing the surface structures already seems to be sufficient to produce a structure having a diffraction-optical effect.

The visual impression of such a security element can be imitated, if at all, only with great effort.

As an optical diffraction effect surface structures are refraction patterns, holograms, as well as grid structures (eg Kinegram ^®, pixels grams) or the like into consideration. They are preferably relief-like diffraction structures, in particular embossed diffraction structures. The diffraction structures can be introduced directly into the substrate. However, they can also be introduced into an additional lacquer layer applied to the substrate, preferably embossed. The diffraction patterns visually visible on the basis of the diffraction structures can be designed as desired. Thus, depending on the desired application or security level on the one hand simplest geometrical patterns, on the other hand, but also complicated image subjects conceivable.

The substrate is preferably a plastic film, preferably PET (polyethylene terephthalate), POP (polyphenylene oxide), PEN (polyethylene naphthalate) or PC (polycarbonate). The film thickness can be between 6 and 100 μm, preferably between 12 and 23 μm.

The substrate is preferably transparent or at least translucent and may also be colored in particular embodiments.

The support may, like the substrate, be a plastic film, but paper, in particular banknote paper based on cotton fibers, may as well be used. Plastic cards or composite materials are used. The support preferably has a black or silvery inherent color or is coated on the side facing the substrate, preferably printed, in order to make the diffraction structures appear optically more brilliant by increased reflection on the support. Just as well, with transparent support, the substrate can be designed accordingly.

Substrate such as carriers may additionally be provided with mechanically and / or visually perceptible feature substances, e.g. Luminescent substances, magnetic materials etc.

The adhesive used in the adhesive layer is, for. For example, commercially available adhesives for bonding supports and substrate materials, e.g. Glue from Morton. According to the invention, the adhesive at least completely fills up the surface structures present in the substrate in certain areas. The thickness of the adhesive layer should therefore be at least as large as the depth of the diffractive optical surface structure. The composition of the adhesive is to be chosen so that at the applied to the surface structures bodies, the surface structures are no longer effective diffraction optically, i. a e.g. holographic effect can no longer be perceived at these points. This can be achieved by making the difference between the refractive indices of the surface structure-containing layer and the adhesive layer small enough. Usually, the refractive indices differ by 0.3 or less, preferably by 0.1 or less.

"Area-wise" in the sense of the invention means that the adhesive fills a portion of the surface structure. The glue can basically exist in any patterns. Simple geometric patterns up to complicated, if necessary also finely structured forms are conceivable. For example, the adhesive is applied over the entire surface, wherein recesses are incorporated in the adhesive surface. Just as well, the adhesive may be grid-shaped, such as in the form of a point grid, be applied. The latter variant has the further advantage that additional information can be incorporated into the surface pattern appearing to the viewer by controlling the size and number of raster elements. Thus, a halftone motif can be converted by means of the raster, whereby the tone values of a template are reproduced by the number and size of the raster elements. By suitable screening of the adhesive even spatial representations are possible.

If simple surface structures are present, the adhesive is preferably processed in complicated patterns. If complicated, complex surface structures are present, it may already be sufficient to secure the adhesive in simple geometrical patterns.

It proves to be particularly advantageous to color the adhesive layer individually. It is also possible to use an adhesive layer containing colored pigments. Due to the colored design of the areas filled with adhesive, they are clearly visible in relation to the regions having the diffraction-optically effective surface structures. The application of the adhesive layers can also take the form of a specific pattern, which is composed of differently colored adhesives.

In particularly preferred embodiments, the information present by means of adhesive and surface structures can be determined by background information, be supplemented for example by a print, in the carrier and / or substrate.

The security element can be generated directly on the value document or security paper or integrated as a separately producible element in the structure or subsequently applied. It can be e.g. to act a security thread, which consists of a self-supporting plastic film. This security thread can be at least partially incorporated into a security paper or security document. However, it is also conceivable to form the security element band or label-like and to attach to the surface of the security paper or value document.

Alternatively, the security element can also be designed as a transfer element. This variant is particularly advantageous if the security element is arranged completely on the surface of the security paper or value document. A "transfer element" in the sense of the invention is a security element which is prepared on a separate layer, for example a plastic film, in the reverse order as it later comes to lie on the security paper and then by means of an adhesive or lacquer layer in a hot embossing process is transferred in the desired outline contours on the security paper or document of value. The separate layer can be removed after the transfer of the security element or remain as a protective layer as an integral part of the security element on the layer structure.

If the security element is arranged on the surface of the security paper or value document, then it can have any outline structures, such as round, oval, star-shaped, rectangular, trapezoidal or strip-shaped outline contours. However, the use of the security element according to the invention is not restricted to the field of the value document. The security element according to the invention can also be used advantageously in the field of product security for securing counterfeiting of any goods. For this purpose, the security element additionally anti-theft elements, such as a coil or a chip have. The same applies to the security paper or security document provided with such a security element.

In the production of the security element, the desired diffraction-optically effective surface structures are first introduced, preferably embossed, into the substrate or a coating layer additionally applied to the substrate. Following this, the adhesive is applied in regions to the surface of the substrate carrying the surface structures. Preferably, the adhesive is printed, e.g. in roll intaglio, bow screen printing. Likewise, the adhesive may also be masked e.g. be sprayed on. The adhesive fills in the surface structures, so that in the areas coated with adhesive, the surface structure is probably no longer seen as a diffraction pattern due to the lack of refraction. The adhesive-equipped substrate is then applied to the substrate.

Alternatively, the carrier may first be provided with adhesive in regions, and then the substrate provided with surface structures may be transferred to the carrier.

Using a single embossing stamp, infinite variations in the visible diffraction patterns can thus be produced solely by the adhesive applied in different patterns. This diversity can be further increased by the use of colored or pigmented adhesives.

The coating method according to the invention offers the advantage that it can be used in an extremely economical manner, i. Save costs and time, individual security elements can be produced even in small quantities.

Due to the lack of an additional reflective layer of e.g. Metal or dielectric, material costs but also cost-intensive vapor deposition processes can be saved.

Due to the visually striking design, the security elements and documents of value produced according to the invention, despite cost-effective manufacturing process on a high security against forgery, since they are easily recognizable without further aids due to the visually striking surface structures and can be very difficult to reproduce.

In addition, the visible diffraction patterns can be precisely positioned by the simple handling of the adhesive and thus appear exactly at the desired location in the final product at any point.

Fig.1

ein erfindungsgemäßes Wertdokument,

Fig. 2

Querschnitt durch das erfindungsgemäße Wertdokument entlang der Linie A - A,

Fig. 3

Querschnitt durch ein erfindungsgemäßes Transferelement.

Further advantages and embodiments will be explained in more detail with reference to FIGS. It should be noted that the figures represent only schematically the layer structure. The proportions shown in the figures do not necessarily correspond to the conditions existing in reality and serve primarily to improve the clarity. It shows

Fig.1

a value document according to the invention,

Fig. 2

Cross section through the value document according to the invention along the line A - A,

Fig. 3

Cross section through a transfer element according to the invention.

Fig.1 shows an inventive document of value in supervision. In the example shown, it is a card 1 with chip 11, which has a region in the cover, which is designed as a security element 2 according to the invention. The security element 2 is shaped like a strip and extends over the entire width of the card 1. The surface of the security element 2 facing the viewer has, according to the invention, partially diffraction patterns 3 that are visible. Of course, the card 1 may have further security elements such as a security thread (not shown).

Fig. 2 shows a cross section along the line A - A in Fig.1 , The card body, in this case made of plastic 6, acts as a support for the adhesive layer 5 present in regions. The cover film 12 can be seen above the adhesive layer 5, which is composed of a plastic substrate 9 and a lacquer layer 4 into which the diffraction structure 7 is embossed. The diffraction structure appears to the viewer as already intricately structured pattern and can contain, for example, the company logo in microfilm as an endless pattern. The upper half of the security element 2 in Fig. 1 , the left part of the Fig. 2 corresponds to this diffractive optical conspicuous pattern with the outline of a rectangle, which, as in Fig.2 was realized by the fact that the entire surface in the lacquer layer 4 diffraction structures 7 were filled to a rectangle with adhesive. The lower half of the security element 2 in Fig.1 that the right part of the Fig. 2 corresponds, shows the same diffraction structures as the upper half, but not with the outline of a rectangle, but in outline of the Letters "PL". This was achieved by applying the adhesive to the substrate with recesses in the form of the letters "PL". Of course, a reverse application of the adhesive would be conceivable, ie the adhesive could with the outline of a rectangle or in the form of the letters "PL." be applied. Furthermore, the adhesive may for example be colored so that the region of the security element 2 surrounding the diffraction structures 3 emerges in color.

Fig. 3 shows that in Fig. 2 This transfer element 8 consists of a separate layer 10, which is optionally provided with a release layer to ensure a defined detachment of the separate layer of the layers to be transferred. In Fig. 3 the separation layer is not shown. The separate layer is followed by a plastic layer 9 and a lacquer layer 4, in which diffraction structures 7 are embossed. Finally, the transfer element 8 also has a partially applied adhesive layer 5, which is activated on transfer to the corresponding security paper or document of value by means of heat and pressure in the areas to be transferred to the cover film 12 on the security paper or document of value. The adhesive layer 5 can be colored in order to achieve special optical effects. However, it is not absolutely necessary that the applied adhesive layer in all areas consists of a colored in the same color glue. Rather, it would also be possible to assemble the adhesive layer 5 in the form of a specific pattern of differently colored adhesives. In a last step, the separate layer 10 is peeled off.

Claims (13)

1. A security element comprising

   - a carrier (6), and

   - a substrate (12) having at least partly optically-diffractively active surface structures (7) at least on the surface facing the carrier (6), and

   - an adhesive layer (5) present between substrate (12) and carrier (6) and at least completely filling the surface structures (7) in certain areas, whereby at least a portion of the areas of the surface structures (7) not filled with the adhesive layer (5) is not directly coated with a reflecting layer, and the areas filled with the adhesive layer (5) are present in the form of a pattern which forms information, characterized in that the adhesive layer (5) is colored with a dye or a color additive.
2. The security element according to claim 1, wherein at least a portion of the surface structure areas not filled with the adhesive layer is not directly coated with a further solid or liquid layer.
3. The security element according to at least one of the preceding claims, wherein the surface structures are embossed diffraction structures.
4. The security element according to at least one of the preceding claims, wherein the diffraction structures are embossed into an additional lacquer layer.
5. The security element according to at least one of the preceding claims, wherein the surface structures are no longer optically-diffractively active in the area of the surface structures filled with the adhesive layer.
6. The security element according to at least one of the preceding claims, wherein the substrate is a plastic film.
7. The security element according to at least one of the preceding claims, wherein the carrier consists of paper or plastic.
8. The security element according to at least one of the preceding claims, wherein the adhesive layer contains color pigments.
9. The security element according to at least one of the preceding claims, wherein the carrier is printed on the side facing the substrate.
10. A value document comprising a security element according to at least one of claims 1 to 9.
11. A security paper for producing a value document according to claim 10, comprising a security element according to at least one of claims 1 to 9.
12. A transfer element comprising a separate layer (10) and a substrate (9, 4) which has at least partly optically-diffractively active surface structures (7) at least on the surface facing away from the separate layer, and an adhesive layer (5) at least completely filling the surface structures (7) in certain areas, whereby at least a portion of the areas of the surface structures (7) not filled with the adhesive layer (5) is not directly coated with a reflecting layer, and the areas filled with the adhesive layer (5) are present in the form of a pattern which forms information, characterized in that the adhesive layer (5) is colored with a dye or a color additive.
13. A method for producing the security element according to at least one of claims 1 to 9, wherein

    - a carrier is supplied,

    - adhesive is applied to the carrier in certain areas, and

    - a substrate with optically-diffractively active surface structures is applied over the adhesive, with the surface structures coming to lie on the adhesive, or

    - a substrate with surface structures is supplied,

    - adhesive is applied to the surface structures in certain areas, and

    - the substrate with the adhesive layer is applied to a carrier, whereby at least a portion of the surface structures not coming to lie on the adhesive is not directly coated with a reflecting layer, and the adhesive is so applied that the areas provided with the adhesive are present in the form of a pattern which forms information, characterized in that the adhesive layer is colored with a dye or a color additive.

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