EP1509402B1 - Security document with an optical security area - Google Patents

Abstract

A security document such as a banknote, comprising an optical security area (3) which consists of a first periodic optical structure, e.g. parallel grid-type lines, a parallel line grid or point grid (1), and which contains a security sign (5) whose contours encompass a second, periodic optical structure, e.g. parallel grid-type lines, a parallel line grid or point grid (2) which is arranged in an offset manner in relation to the first. The recognizibility of the security sign (5) is increased by observation with the aid of a see-through element (4), said element (4) being applied to an area of the security area (4) in such a way that the area of the security sign contained in the area covered by the see-through element (4) can be recognized by the naked eye.

Description

The invention relates to a document of value, e.g. Banknote having an optical security area which has a first periodic optical structure, e.g. parallel bar grating lines, a parallel line grid or dot screen, and which contains a safety sign whose contours have a second periodic optical structure, e.g. parallel grating lines, a parallel line grid or dot screen, which are arranged offset to the first, and with a see-through element, wherein the recognizability of the security sign is increased by viewing with a see-through element. Safety signs of the type mentioned at the outset are also referred to as "hidden images" whose existence within the security area of a value document is difficult to detect with the naked eye. These can be hidden lettering, pictures or geometric figures and these stand out clearly when viewed with a see-through element from the ground. The see-through element may be formed of a grating, a lenticular lens or similar ancillary devices that clearly visualize the offset between the first and second periodic optical structures. It is only with the help of the see-through element that a clearly recognizable contrast arises on the security area of the value document, as a result of which the hidden image becomes visible to the naked eye.

Such safety signs are eg from the US 6,317,226 B known. This deals with a moiré pattern, which is characterized by the overlap of two identical patterns, of which the upper pattern is formed by transparent and opaque areas, and is called a decoding film. This expediently has a binary line pattern. In this case, a shift of the pattern is given between the lower coding pattern and the decoding pattern.

The WO 02 00446 A discloses a security device comprising a substrate and provided with a surface relief which determines an optically variable effect generating structure. In this case, the optically varying effect against a background can be considered, which is determined by a reflection-increasing material. In this case, a bar pattern is provided with sections at an angle to the other lines having dashes.

A disadvantage of such solutions is that such patterns are easy to counterfeit. Since such security areas are printed directly on the document of value in many cases, they can be falsified with the help of high-resolution copiers in a relatively simple manner, or even by professional counterfeiters in a relatively simple manner be integrated into the document of value by means of scanning and subsequent image processing.

DE 197 29 918 A1 discloses a value document with a see-through element 3 and a security area 2 which are not firmly connected to each other.

The object of the invention is therefore to provide a document of value of the type mentioned, which has an increased security against counterfeiting.

According to the invention, this is achieved in that in order to increase the visibility of the security mark on a region of the security area, a see-through element is firmly connected to the value document, and that the part of the security sign contained in the area covered by the see-through element is constantly visible to the naked eye ,

After forming the security area with the security mark contained therein, the separately produced see-through element is applied to the value document according to the invention, so that it is firmly connected to it. For this purpose, various technologies can be used, ranging from gluing to hot stamping. It is also conceivable

Continue on page 2 of the original description layer by layer structure of the see-through element on the value document. The transparent element applied to the surface of the document of value makes a part of the security mark on the document of value permanently recognizable, while the remaining part remains hidden to the naked eye. In this way, the finding of the security mark on the value document is facilitated, whereby the test times can be shortened. This application makes a part of the "hidden images" visible. This is itself a difficult to imitate security feature, because - due to the moiree effect - results in a characteristic effect that can not be imitated by simple color copy. The test for authenticity is carried out with an additional see-through element, for example by means of transparent film or card with a line grid or grating, lenticular lens, od. The like. Through which the security area is considered. The criterion for the security against counterfeiting is the high dimensional accuracy required of the transparent element applied to the value document and its positional accuracy relative to the security area. If there is a discontinuity in the course of the contours of the security mark when viewing with the additional see-through element at the transition point between the area covered by the applied see-through element and the rest of the security area, then there is a forged value document, because a true value document makes more visible and invisible part of the security mark when viewed through an additional, for example, placed on the document of value transparent element the completely and undisturbed contours of the security sign.

In a further embodiment of the invention, half of the area occupied by the security area can be covered by the see-through element. With this selected division, the location of the safety sign can be seen at a glance.

A further feature of the invention may be that the see-through element has a similar or identical optical structuring as the first or second periodic optical structure.

Thus, the required for the first and second periodic optical structure two-dimensional design can also be applied to the applied see-through element, whereby the thickness of the see-through element can be kept very low. It therefore stands out only imperceptibly on the value document and thereby unfolds no disturbing when using the value document effect. However, the security area can also be formed in a recess of the value document surface and the see-through element embedded in this recess.

According to a further embodiment of the invention, the first periodic optical structure and the second periodic optical structure may each consist of parallel grating lines, parallel line grids or dot patterns, the spacing between adjacent grating lines, parallel line grids or dot patterns preferably being 1.5 times the line width of the graticule lines, parallel line grids or dot screens.

Line grids and rasters of this type can be produced very simply by printing technology and produce a clearly recognizable contrast.

Furthermore, in another embodiment of the invention, it may be provided that the grating lines, the parallel line grating or the dot pattern of the first periodic optical structure are displaced by an offset distance (L) from the grating lines, the parallel line grating or the dot matrix from the second periodic optical line Structure are offset in parallel.

Due to the parallel displacement of the first and the second periodic, optical structure, when viewed through a see-through element a very well recognizable contrast, especially if according to an embodiment of the invention, the displacement distance (L) is approximately equal to half the distance (a) between the grating lines, the parallel line grid or dot pattern of the first or second periodic optical structure. A variant of the invention may further consist in that the see-through element is formed by a transparent film with parallel grating lines, parallel lines or dot patterns, which are e.g. is glued to the document of value.

Another variant of the invention may be formed in that the see-through element is formed by a provided with parallel, elongated slots film, preferably metallized plastic film.

This type of see-through element can be impressed in a simple manner hot on the surface of the value document according to the invention. Furthermore, the film may be part of a hologram film, which is impressed on the document of value. As a result, the hologram and the see-through element can be applied to the value document in one operation.

• Fig.1 eine Draufsicht auf ein Detail eines Wertdokuments gemäß Stand der Technik;
• Fig.2 und Fig.4 jeweils eine Draufsicht bzw. teilweise Draufsicht auf Ausfiihrungsformen eines Durchsicht-Elements für ein erfindungsgemäßes Wertdokument;
• Fig.3 eine Draufsicht auf eine Ausführungsform des erfindungsgemäßen Wertdokuments;
• Fig. 5 eine Draufsicht auf eine andere Ausführungsform des Sicherheitsbereiches eines erfindungsgemäßen Wertdokumentes;
• Fig. 6 eine Draufsicht auf den Sicherheitsbereich gemäß Fig. 5 mit appliziertem Durchsicht-Element;
• Fig. 7 eine Draufsicht auf den Sicherheitsbereich gemäß Fig. 6 mit einem zusätzlichen Durchsichtelement; und
• Fig. 8 bis 10 eine Draufsicht einer weiteren Ausführungsform des Sicherheitsbereiches eines erfindungsgemäßen Wertdokumentes, entsprechend den Fig. 5 bis 7.

The invention will be explained in detail with reference to the exemplary embodiments illustrated in the drawings. It shows

• Fig.1 a plan view of a detail of a value document according to the prior art;
• Fig.2 and Figure 4 in each case a plan view or partial plan view of embodiments of a see-through element for a value document according to the invention;
• Figure 3 a plan view of an embodiment of the value document according to the invention;
• Fig. 5 a plan view of another embodiment of the security area of a value document according to the invention;
• Fig. 6 a plan view of the security area according to Fig. 5 with applied see-through element;
• Fig. 7 a plan view of the security area according to Fig. 6 with an additional see-through element; and
• Fig. 8 to 10 a plan view of another embodiment of the security area of a value document according to the invention, according to the Fig. 5 to 7 ,

Fig.1 shows a section of an optical security area 3 of a value document in magnification, as is known from the prior art. The security area 3 is traversed by white curved lines 8 and black curved lines 7, which are part of a higher-level graphic design of the value document, which are of no significance for the invention.

In the context of the invention, securities are banknotes, checks, traveler's checks, shares, identity cards, check cards or the like, which have a printable surface and are to be protected against unauthorized duplication. For this purpose, the security area 3 has a first periodic optical structure in the form of printed, parallel grating lines 1, which in FIG Fig.1 held in black on a white background. The periodicity consists in the same spacing of the grating lines 1, the distance (a) between adjacent grating lines 1 preferably being 1.5 times the line width of the grating lines 1.

In the security area 3, a security mark 5 is included, the contours of which enclose a second optical structure, which in Fig.1 are realized in the form of printed, parallel grating lines 2 in black on a white background having the same mutual distance a as the grating lines 1 of the first periodic optical structure, but by the offset distance L against the grating lines 2 of second periodic, optical structure are offset in parallel. The offset distance L is approximately (a / 2). The color contrast between grating lines 1 or grating lines 2 and the background can be chosen arbitrarily within the scope of the invention.

However, the first and the second periodic optical structure can also be in the form of dot grids, for example, as in FIG Figure 3 be implemented parallel line grids or in other optical periodic form, wherein the second optical periodic structure is each delimited by the contours of the security mark with respect to the first optical periodic structure.

Due to the in Fig.1 selected magnification, the safety sign 5 is relatively easy to recognize. With a suitable choice of the line spacing and the line thickness but the safety sign 5 disappears almost completely in the security area 3 and is not visible to the naked eye.

The recognizability of the security sign 5 is determined by viewing with a see-through element 4, as shown in FIG Fig.2 and Figure 4 is shown, wherein the see-through element 4 has a similar or identical optical structuring as the first or second optical structure. However, other suitable see-through elements, for example lenticular lenses, can also be used.

In the embodiment according to Fig.2 the see-through element is formed by a transparent film 4 with parallel grating lines 9, which are arranged parallel to each other at a distance (a). If the film 4 placed on the security area 3 and the grating lines 9 brought in parallel position to the grating lines 1, 2, then depending on the displacement of the grating lines 9 and the grating lines 1 and 2, the safety sign 5 either dünkler or brighter to see against the white background and thus significantly increased the visibility of the same.

The film 4 may also have another optically periodic shape, e.g. Dot matrix od. Like. Have.

According to the invention, it is now provided that the see-through element 4 is applied to a region of the security area 3 in such a way that the part of the security sign 5 contained in the area covered by the see-through element 4 can be seen with the naked eye ( Figure 3 ).

Thus, the see-through element 4 made separately from the value document is applied to the security area 3 in partial coverage thereof, the method of application being not subject to any restrictions.

In Figure 3 the first and the second optical, periodic structure 1, 2 are formed by mutually offset dot patterns. As in Figure 3 recognizable, covers the see-through element. 4 the lower half of the hidden in the security area 3 security sign 5, which is composed of the letter sequence "oebs".

Such a designed security area 3 has a high security against counterfeiting, since the application of a see-through element 4 must be made with a very high accuracy and the durability can be reliably ensured on the document of value only with high equipment complexity.

If, on the other hand, a forgery of the value document attempts to achieve that a film 4 provided with a prefabricated lettering, which forms the see-through element, is applied to the security area 3, then the uncovered part of the lettering of security sign 5 does not exactly coincide the course of the lettering on the slide 4 match. The coincidence in the transition from the film 4 to the printed security area 3 can be easily detected e.g. be detected by viewing by means of a lenticular lens. Even small deviations result in a strongly distorted contrast in the transition region.

The whole arrangement as in Figure 3 Also, it can not be copied for the purpose of forgery as a whole, because the bitmap can be increased beyond the resolution limit of a copier.

Figure 4 shows another variant of a see-through element 4, which is formed by a provided with parallel, elongated slots 10 film 4, preferably a metallized plastic film. Such a structure can be produced very precisely even for small distances, for example by etching or selective demetalization, and can be hot-stamped onto a value document, for example. It is possible to integrate the provided with slots 10 or demetallisierten areas film 4 in a hologram, so that it is part of the same.

In Fig. 5 the security area 3 of another value document according to the invention is shown. According to Fig. 6 can be applied to this the see-through element 1, so that a part of the safety sign 5 is constantly visible to the naked eye. During the test, the security area is determined according to Fig. 7 viewed through the additional see-through element 6, whereby the entire safety sign 5 can be seen.

In the Fig. 8 to 10 is a further embodiment of the security area 3 of a value document according to the invention analogous to Fig. 5 to 7 shown. To facilitate a quick and accurate placement of the additional see-through element 6, the additional see-through element 6 markings 61 which can be brought in accordance with marks 31 on the value document according to the invention.

The security area 3, in particular the see-through element 4 and / or the dash or dot screen, can additionally be provided with further security features, such as e.g. Fluorescent or effect colors are provided to further increase safety.

Claims (9)

1. A security document such as a banknote, comprising a see-through element (4) and an optical security area which comprises a first periodic optical structure such as parallel grid-type lines, a parallel line grid or point grid and comprises a security sign whose contours encompass a second periodic optical structure such as parallel grid-type lines, a parallel line grid or point grid which is arranged in an offset manner in relation to the first one, characterized in that for the purpose of increasing the recognizability of the security sign (5) in a region of the security area (3) the see-through element (4) is fixedly connected with the security document and that the part of the security sign (5) contained in the area covered by the see-through element (4) can continually be recognized by the naked eye.
2. A security document according to claim 1, characterized in that half the area covered by the security area (3) is covered by the see-through element (4).
3. A security document according to claim 1 or 2, characterized in that the see-through element (4) has an optical structuring similar or identical to the first or second periodic optical structure.
4. A security document according to claim 1, 2 or 3, characterized in that the first periodic optical structure and the second periodic optical structure each consist of parallel grid-type lines, parallel line grids or point grids (1, 2), with the distance between the adjacent grid-type lines, parallel line grids or point grids (1, 2) being preferably 1.5 times the line thickness of the grid-type lines, parallel line grids or point grids (1, 2).
5. A security document according to claim 4, characterized in that the grid-type lines, parallel line grids or point grids (1) of the first periodic optical structure are offset in parallel by an offset distance (L) relative to the grid-type lines, parallel line grids or point grids (2) of the second periodic optical structure.
6. A security document according to claim 5, characterized in that the offset distance (L) is approximately equal to half the distance (a) between the grid-type lines, the parallel line grids or point grids (1, 2) of the first or second periodic optical structure.
7. A security document according to one of the preceding claims, characterized in that the see-through element is formed by a transparent film (4) with parallel grid-type lines, parallel line grids or point grids (9).
8. A security document according to one of the claims 1 to 6, characterized in that the see-through element is formed by a film (4), preferably a metalized plastic film, which is provided with parallel, oblong slots (10).
9. A security document according to claim 8, characterized in that the film is a component of a hologram film which is hot-stamped onto the security document.

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