WO1995016574A1

WO1995016574A1 - Visually identifiable, optical security element for security papers

Info

Publication number: WO1995016574A1
Application number: PCT/DE1994/001426
Authority: WO
Inventors: Jürgen Herrmann; Werner Reinhart
Original assignee: Leonhard Kurz Gmbh & Co.
Priority date: 1993-12-18
Filing date: 1994-12-02
Publication date: 1995-06-22
Also published as: AU1105195A; DE4343387A1; TW383108U

Abstract

Visually identifiable, optical security elements (2, 20) for security papers or other objects to be safeguarded has at least two partial areas (2a to 2e, 20a to 20d) identifiable with the naked eye and apparently differently structured when exposed to light. The structure of at least some of the partial areas is such that when the lighting or observation direction is changed the visible optical image also changes. The essential aspect of the security elements (2, 20) is that their partial areas (2a to 2e, 20a to 20d) are structured in such a way that adjacent partial areas (2a to 2e, 20a to 20d) have a clearly contrasted appearance for an observer, independently from the observation angle, whereas each partial area has a uniform structure in itself.

Description

Visually identifiable, optical security element for documents of value

The invention relates to visually identifiable, optical security elements for documents of value, e.g. Banknotes, official credit cards, ID cards or check documents, or other objects to be secured, which include at least two neighboring sub-areas that appear differently structured when illuminated and that can be identified by the unarmed eye.

Such optical security elements, which change their appearance depending on the viewing angle or the lighting conditions, are known primarily for credit cards, but also for other areas of application. So far, the aim has been to use as many different optical effects as possible in a security element, e.g. Color changes, movement effects, holographic effects, three-dimensional manifestations etc., summarized in one motif to counterfeit the

To make the security element as difficult as possible. this has However, the disadvantage that such a security element due to its unspecific appearance, especially for the layperson and under the conditions of, for example, payment transactions, where there are unfavorable lighting conditions and only a very short inspection time

Is available, can not be checked for authenticity. In the case of such known optical security elements (so-called OVDs), the forgery of the security elements can in fact be made more difficult; However, a reliable check for authenticity is only possible with appropriate devices or a large visual inspection effort, but not easily and quickly by a layperson. Another disadvantage is that the non-specific appearance of those with different effects concentrated in one motif and therefore from

OVDs overloaded with information are reproduced in a deceptive manner even under reproductions with color copiers or printing technology methods for the layperson under the aforementioned conditions. The security effect actually achieved is therefore comparatively low despite the considerable effort involved in the production of the OVDs.

The invention is therefore based on the object of being visually identifiable, optical and in terms of

To design the variable security element in such a way that it can be easily and in particular quickly and under unfavorable by a layperson

Lighting conditions can be checked for authenticity, with the use of special instruments or

Devices for authenticity testing should not be necessary, which also means that no special observation or illumination angles have to be observed for authenticity testing. In addition, an impressive re-enactment the OVD's can be prevented by printing and copying technology.

To solve these tasks, it is proposed according to the invention in a security element of the type mentioned at the outset that the partial areas of the security element are structured in such a way that, for an observer, adjacent partial areas appear to be clearly contrasting with one another, or areas that appear homogeneous are reproduced in a counterfeit manner in the case of counterfeiting, whereby in addition, each sub-area is structured in a uniform manner. In the simplest case, the security element comprises only two correspondingly clearly distinguishable, in each case uniform partial areas, so that it would be sufficient for the user if he noted the optical effects occurring in two partial areas.

The invention is therefore based on the basic consideration that, for the purpose of the invention aimed for simple and rapid identification, even under unfavorable lighting conditions and without observing special test conditions, it is essential to be limited to a comparatively small number of different and clear optical effects, whereby the individual optical effects are each provided in certain sub-areas of the security element, which are sufficiently large and, if possible, have a certain shape so that the viewer can recognize and distinguish them quickly and easily. Identification is further facilitated by the fact that only one uniform structure is provided in each of the partial areas that clearly contrast with one another or contrast with reproduction. One becomes expediently so proceed that at least individual sub-areas are designed in such a way that the optical effect sought in these sub-areas can still be clearly recognized even under unfavorable lighting conditions, for example diffuse or low light. Such easily recognizable effects are, for example, color changes, clearly defined movements or changes in shape in the area of the light visible to the viewer or clearly visible changes between structured and high-gloss areas.

Within the scope of the invention it is possible, for example, that at least a partial area of the security element has a light-diffractive and / or refractive structure (diffraction structure), e.g. a hologram,

Interference pattern, diffraction grating or the like. Has, depending on the type of diffraction structure used, the most diverse effects can be achieved. The diffraction structure can expediently be designed such that when the illumination or

Viewing angle a defined, as clear as possible color change is generated. Another possibility according to the invention is that the diffraction structure causes movement effects, for example color changes or changes in geometric structures, when the illumination or viewing angle changes. Finally, it is also possible for the diffraction structure to be composed of such structural elements which, for example in a partial area, each have two or more different geometric figures, depending on a defined viewing angle, for example two different letters or a change between a letter or a number on the one hand and the Representation of a head etc. on the other hand. What is important in this Context, however, that the changes dependent on the illumination or viewing angle are such that, regardless of the actual viewing angle, there is always the contrast impression between adjacent partial areas.

Clear and easily perceptible optical effects can also be achieved if the different sub-areas of the security element have a different degree of reflection.

It is also possible within the scope of the invention that at least one partial area has a matt structure, whereby both chromatic and achromatic matt structures can be provided.

A further design option for the partial areas is that at least one partial area is not visibly structured, the at least one partial area expediently being glossy, preferably highly reflective metallic. It is precisely the contrast between a highly reflective and thus apparently the same at different viewing or lighting angles on the one hand and an optically contrasting changing its appearance depending on the lighting or viewing angle is a characteristic feature that the user of the document of value can easily memorize .

Another possibility for the different design of partial areas, which are very easy for the viewer to identify, is that adjacent partial areas have different colors, the different colors are expediently formed by a transparent colored lacquer which also serves as a protective lacquer, ie covers the structure in such a way that scratching or changing of the structure, whether intentionally or unintentionally, for example through use, is prevented, at least in some areas is provided with a diffraction or matt structure.

The correct identification of the individual partial areas is reliably ensured if, as provided according to the invention, each partial area has a minimum diameter or minimum dimensions in each direction of at least 0.3 mm, preferably of at least 2 mm.

The recognizability or identification of a security element according to the invention is further facilitated if a first partial area surrounds at least one further partial area in a frame-like manner, advantageously the _. frame-like first partial area surrounds at least two further partial areas spaced apart from one another. In this embodiment, the procedure is advantageously such that the frame-like first partial area is glossy and the further partial area (s) has (have) a diffraction or matt structure. The reflective or glossy frame draws the viewer's attention particularly to the partial areas arranged within the frame. Even with reproductions, for example with color copying machines, such an arrangement creates a good contrast effect, which is clearly perceptible to the viewer, in that the more or less chromatic, low optical density reproduction of the diffraction-optically effective structural areas differs from that in FIG high density values reproducible high-gloss sub-areas clearly stands out, regardless of the respective viewing angle.

In connection with the invention, it is also possible for at least one partial area to be formed by a thin-film element, whereby thin-film element is to be understood to mean that a transparent, generally colorless layer is provided in this area, the thickness of which is so small that interference phenomena occur . For this purpose, the layer must in any case be thinner than a quarter of the wavelength of the light used for viewing.

If, as is also possible according to the invention, at least a partial area of the security element is transparent, there is also a special optical effect which is easily perceptible to the viewer. In addition, in this case, one has the advantage that the area within the security element

The surface of the document of value to be secured, for example a correspondingly printed paper, shines through, a design that is very difficult to achieve in an attempt to counterfeit.

It is also possible for at least one partial area to be designed differently from the adjacent partial area (s) by removing a metallization covering several partial areas in certain areas. The path of demetalization will then be followed if either transparent partial areas are aimed for or a diffraction structure provided over the entire surface of the security element is divided into different partial areas and for this purpose the diffraction structure is to be made invisible in some areas.

According to the invention, the document of value can be further secured if the

Security element is provided with at least one additional security indicator. As an additional security identifier, a print or a corresponding embossment that at least partially encompasses all partial areas can expediently be provided, this pressure usually after the application of the

Security element will be attached to the value document.

To form the additional security identifier in the form of a special print, special colors are advantageously used, for example mineral or metallic effect colors, liquid crystal colors or coatings, IR and / or UV-active colors, daylight fluorescent colors or iridescent colors.

Another possibility for generating an additional security identifier is to provide a special, difficult to falsify design of the diffraction structure of at least a partial area of the security element.

As can be seen from the above explanations, the aim of the security element according to the invention is to use essentially only a few, for example only two, selected effects with a high level of attention. These effects, which are as clear as possible with regard to their optical effect, are applied to the security elements according to the invention in such a way that at least individual elements even under unfavorable lighting conditions and with any

Viewing angles are still clearly visible and effective. The effects themselves are appropriately in a cognitively favorable external form, e.g. Present as a concrete symbol or image from the design of a banknote, particularly good results can be achieved primarily through a correlation between highly reflective, non-diffractive areas on the one hand and diffractive areas on the other. The use of highly reflective sub-areas has the additional advantage that if a counterfeit is attempted by copying or color printing, the highly reflective surfaces are black, while diffraction-optically effective structures are preferably reproduced diffusely and in non-specific colors, differences that are easy to perceive even under the unfavorable conditions of payment transactions should.

In principle, it is possible to manufacture the security element according to the invention in a wide variety of ways and in particular to form it on a value document. With regard to handling and attachment to the document of value, however, it is particularly expedient if, according to the invention, the security element is part of an embossing or laminating film which has an adhesive layer for fixing the security element to the document of value or object. Manufacturing processes for such embossing or laminating films are generally known and are therefore not to be explained in more detail here. It is also readily clear to the person skilled in the art how, for example, hot stamping foils have to be constructed if certain optical effects are to be achieved highly reflective surfaces or surfaces with a diffraction structure should be present.

Further features, details and advantages of the invention result from the following description of preferred exemplary embodiments of value documents with security elements according to the invention with reference to the drawing, in which each shows schematically:

Figure 1 shows a part of a security with a first

Embodiment of a security element;

Figure 2 shows a section along line II-II in Figure 1 and Figure 3 shows part of a security with a second

Embodiment of a security element according to the invention.

FIG. 1 shows a part of a document of value 1, for example a security such as a bank note etc., on which a security element, denoted overall by 2, is attached in accordance with the invention.

In the exemplary embodiment in FIG. 1, the visually identifiable, optical security element 2 essentially comprises three partial areas 2a, 2b and 2c, these partial areas being dimensioned such that they have minimum dimensions in each direction or a minimum diameter of at least 0.3 mm, but preferably of have at least 2 mm. This means that the frame-like partial area 2a has a frame width a of at least 0.3 mm, but expediently of at least 2 mm has. The subregions 2b and 2c are correspondingly at least 0.3 mm, but preferably at least 2 mm wide and high.

As indicated by the illustration in FIG. 1, the frame-like first partial region 2a in the exemplary embodiment in FIG. 1 is reflective, for example a high-gloss metallization.

The subregions 2b and 2c have different surfaces, each having a diffractive or refractive optical effect. For example, the surface of the sub-area 2b can be formed by a diffraction structure that produces a color change, while the surface of the sub-area 2c can be structured in such a way that when the illumination or viewing angle changes, a color change occurs, for example in the sense of a beam rotation, as is particularly the case of decorative films has been known for a long time.

In the exemplary embodiment in FIG. 1, additional structures 2d and 2e in the form of the letters "A" and "X" are arranged within the partial areas 2b and 2c, these structures 2d and 2e differing in surface quality from the rest of the partial areas 2b and 2b, respectively. 2c differentiate. For example, as is assumed in the exemplary embodiment in FIGS. 1 and 2, the surfaces of the letters “X” and “A” can have a matt structure. The attachment of letters or the like. is particularly useful if the document of value is a banknote. In this case, the respective short designation of the relevant currency can be used instead of the letters "A" and "X" are, for example for Deutsche Mark the letter combination "DM".

As can be clearly seen from FIG. 1, the frame-like partial area 2a surrounds the partial areas 2b and 2c such that there is a small distance 3 between the partial area 2a and the partial areas 2b and 2c. In the same way, the partial areas 2b and 2c are separated from one another by a small distance 4, the security element having no surface structure in the distance areas 3 and 4. Rather, in the exemplary embodiment shown, it is transparent in the partial areas 3 and 4, so that the surface 5 of the value document 1 shines through in the area of the distances 3 and 4 within the security element 2, a circumstance which helps to improve the security effect of the security element .

The security element 2 of the exemplary embodiment in FIGS. 1 and 2 is, as is particularly clear from FIG. 2, part of a hot stamping foil and is applied using a corresponding technique, i.e. transferred to the surface 5 of the document of value 1 by means of a stamp under the action of heat and pressure from a carrier 6 shown in broken lines in FIG.

The structure of the security element 2 can also be seen in greater detail from FIG.

Starting from the carrier film 6, this comprises a transparent, deformable protective lacquer layer 7, a lacquer layer 8 and an adhesive layer 9 for fixing on the surface 5 of the security 1. The corresponding diffraction or matt structures are formed at the interface 10 between the transparent, deformable protective lacquer layer 7 and the lacquer layer 8, these structures being produced by appropriately embossing the protective lacquer layer 7 as long as it is still deformable.

FIG. 2 clearly shows that there are diffraction structures 11 in the region 2b in the form of essentially parallel lines of a certain line frequency and depth. In contrast, in the area 2d of the letter "A" a matt structure 12 is produced, which ensures a diffuse reflection of light. Outside sub-area 2b, i.e. especially in the area of the distances 3 and the glossy frame 2a, the surface 10 between the lacquer layers 7 and 8 is smooth.

In order to make the diffraction and matt structures clearly visible and to produce the high-gloss surface of the frame 2a, a metallization 13 is provided between the two lacquer layers 7 and 8, the metallization where the distance 3 between the frame 2a and the partial areas 2b and 2c is to be generated.

Finally, FIG. 2 also indicates that the protective lacquer layer 7 can be colored in the section 14 corresponding to the partial area 2b, although the coloring must take place in such a way that the protective lacquer layer 7 remains transparent, in order to prevent the security element 2 applied to the document of value 1 to be able to recognize the individual partial areas 2a, 2b and 2c perfectly. The transparent coloring of the protective lacquer layer 7 in the area 14 offers the possibility of the two partial areas 2b and 2c contrast in color to each other or to the frame 2a, but also to the surface 5 of the document of value 1.

The hot stamping foil, which is used to produce the security element 2 on the value document 1 according to FIGS. 1 and 2, is produced in a manner known per se. A transparent protective lacquer layer 7 is first applied to a suitable carrier 6 in a customary, preferably printing process, the

Application of a printing process allows the application of differently colored areas without difficulty. As long as the protective lacquer 7 has not yet fully hardened or - when using a thermoplastic lacquer for the protective lacquer layer 7 - under the action of heat, the structure 11, 12 is then introduced in a corresponding replication process. Subsequently, a soluble, expediently water-soluble lacquer is printed on, for example, where the non-metallized spacing 3, 4 is to be provided. ^'Reference is now provided the pointing away from the carrier 6, partially restructure surface of the protective lacquer layer 7 with a metallization 13, for example vapor-deposited in a vacuum to a corresponding aluminum layer. After the metal layer 13 has been applied, it is then removed in the region of the distances 3 and 4, for example by washing out the water-soluble lacquer layer and correspondingly detaching the metal layer in these regions. Now the additional lacquer layer 8 and, if necessary, the adhesive layer 9 is applied to complete the hot stamping foil.

In the embodiment of FIG. 3, a document of value 1, for example part of a banknote, is again shown, but here the security element 20 consists of four substantially identical partial areas 20a, 20b, 20c and 20d, which each have only different surface structures, which is to be indicated by the different hatching. "Surface structures" is not only to be understood as a spatial design as shown in FIG. 2. The “surface structures” of the partial areas 20a to 20d can also be produced, for example, only by different coloring, by using correspondingly thin lacquer layers, by different reflectivities, etc. However, it is particularly favorable in the case of an arrangement according to FIG. 3 if the partial areas 20a to 20d show, for example, targeted color changes, for example in the sense of a color shift from left to right and in the opposite direction from right to left when the viewing angle changes.

In the exemplary embodiment in FIG. 3, an additional security identifier is now provided in the form of a pressure 21 that overlaps all sub-areas 20a to 20d of the security element 20, the expedient procedure being such that the pressure 21 is formed by self-contained and uninterrupted lines, which in turn is a Counterfeiting is difficult, since continuous printing makes it practically impossible to cut out parts of the document of value and replace them with others.

Furthermore, you will usually use 21 special colors for printing, eg mineral or metallic effect colors, liquid crystal colors or coatings, IR or UV active colors, daylight fluorescent colors or iridescent colors. If such special colors are used, a further security check can then be carried out by using special light for lighting done, whereby the print, if the correct wavelength is used for lighting, lights up accordingly or takes on a specific color.

An additional security label cannot only be achieved by overprinting or overprinting. For example, it would also be conceivable to provide at least one of the partial areas 20a to 20d of the security element 20 with a particularly difficult-to-counterfeit optical structure, the precise configuration of which can also only be identified using special instruments, at least using a magnifying glass.

The application of the security element according to the invention was essentially explained above only for securities. Of course, however, the security element according to the invention can also be applied to other substrates, in particular plastic cards, surfaces of objects, etc., the desired advantages also being obtained in these cases.

Claims

Patent claims

1. Visually identifiable, optical

Security element for documents of value, e.g. Banknotes, official credit cards, ID cards or check documents, or other items to be secured

Objects which comprise at least two adjacent, differently structured sub-areas that can be identified with the unarmed eye, characterized in that the sub-areas (2a to 2e, 20a to 20d) of the security element (2, 20) are structured such that for a viewer regardless of the viewing angle neighboring sub-areas appear clearly contrasting with each other and / or, in the case of counterfeiting, homogeneously appearing areas are reproduced in a contrasting manner by copying or by means of printing technology, and that each sub-area is structured in a uniform manner.

2. Security element according to claim 1, d a d u r c h g e k e n n z e i c h n e t that at least a partial area (2a to 2e, 20a to 20d) a light diffractive and / or refractive structure (diffraction structure) (11), e.g. a hologram,

Interference pattern, diffraction grating or the like. having.

3. Security element according to claim 1 and 2, so that the diffraction structure (11) generates a defined color change when the illumination or viewing angle changes.

4. Security element according to claim 1 and 2, so that the diffraction structure (11) changes motion effects, e.g. when changing the illumination or viewing angle, e.g. Color changes or changes in geometric structures.

5. Security element according to one of the preceding claims, that the sub-areas (2a to 2e, 20a to 20d) of the security element (2, 20) have a different degree of reflection.

6. Security element according to one of the preceding claims, characterized in that at least one partial area (2d, 2e) has a matt structure (12).

7. The security element as claimed in one of the preceding claims, that at least one partial area (2a) is not visibly structured.

8. The security element as claimed in claim 7, so that the at least one partial area (2a) appears shiny.

9. The security element as claimed in claim 7 and 8, so that the at least one partial region (2a) is highly reflective in metal.

10. Security element according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that mutually adjacent sub-areas (2a; 2b, 2c) have different colors.

11. Security element according to claim 10, characterized in that the different color is formed by a transparent colored lacquer (7) which simultaneously serves as a protective lacquer and at least in partial areas (2b, 2c) with a diffraction (11) or matt structure (12) is.

12. Security element according to one of the preceding claims, characterized in that each sub-area (2a to 2e, 20a to 20d) one Has minimum diameter or minimum dimensions (a) in each direction of at least 0.3 mm, preferably of at least 2 mm.

13. The security element as claimed in one of the preceding claims, that a first partial area (2a) surrounds at least one further partial area (2b, 2c) in a frame-like manner.

14. The security element as claimed in claim 13, so that the frame-like first partial region (2a) surrounds at least two further partial regions (2b, 2c) arranged at a distance (4) from one another.

15. Security element according to claim 13 or 14, characterized in that the frame-like, first partial region (2a) is glossy and the further partial region (s) (2b, 2c) has a diffraction (11) or matt structure (12) ( exhibit).

16. Security element according to one of the preceding claims, that a at least one partial area (2a to 2e, 20a to 20d) is formed by a thin-film element.

17. Security element according to one of the preceding claims, characterized in that at least one partial area (3, 4) is transparent.

18. Security element according to one of the preceding claims, characterized in that at least one partial region (3, 4) by region-by-region removal of a plurality of partial regions (2a to 2e) covering metallization (13) relative to the or the adjacent partial region (s) (2a to 2c ) is designed differently.

19. The security element as claimed in one of the preceding claims, that it is provided with at least one additional security indicator (21).

20. The security element as claimed in claim 19, so that an additional security indicator (21) is provided with a print or a corresponding embossment that at least partially encompasses all sub-areas (20a to 20d).

21. The security element as claimed in claim 19 or 20, so that special colors are provided to form the additional security indicator (21).

22. Security element according to one of claims 19 to 21, characterized in that the additional security identifier is formed by a special, difficult to forge design of the diffraction structure of at least one partial area (20a to 20d).

23. Security element according to one of the preceding claims, characterized in that the security element (2, 20) is part of an embossing or laminating film (6, 7, 8, 9) which has an adhesive layer (9) for fixing the security element (2) the document of value (1) or object.