EP1030786B1 - Security feature for a security document or document of value with a fractal laminate system - Google Patents

Abstract

A security feature for security documents or documents of value, comprising a transparent body (2) provided with devices for representing graphical information according to an angle (18, 19, 20) between the direction of illumination and the direction of observation. Said devices consist of almost overlapping laminae (7, 8) arranged in the form of steps in said body (2). Preferably, the lamellae (7, 8) are fractally embodied and arranged in the body (2) in ascending order.

Description

The invention relates to a security feature for value and security documents according to the preamble of claim 1 and a method for its Production.

State of the art in the arrangement of security features for value and Security documents are so-called multiplex holograms. It is about a hologram, which shows different images from different perspectives created for the viewer. Furthermore, so-called interference layers are in foils or generally known in transparent bodies. With such interference layers are thin optical layers, the angle-dependent graphic or create colored effects - depending on the viewing angle.

So-called variable displays are also known, these are lens arrays, which about printing or security features on one Security document can be arranged and depending on the viewing direction of this Lens produce a different image depending on the viewing angle.

The disadvantages of the techniques mentioned are that holograms and Inference layers only poor under a variety of lighting conditions show. There are also holograms and interference layers wavelength dispersive, d. H. it comes to the consideration here different color fringes in white light, depending on the viewing angle.

The lens arrays mentioned above require complex manufacturing technologies and a certain finite substrate thickness.

US 3,887,742 shows a security feature for a document of value, namely one Copy protection, which consists of a transparent film and within it Foil slanted slats are provided. These slats are black or reflective and cause that in an observation direction Information located below the security feature is readable and in the other direction this information is not visible to the observer. In this in the other direction, the observer then receives the graphic information of the Slats, namely black or reflective transmitted.

DE 25 40 846 A1 shows a protective cover for documents against copying in Form of a transparent film in which black slats are arranged at an angle.

The invention is therefore based on the object of a security feature to further develop the type mentioned at the beginning, from different perspectives different graphical information in a simpler and cheaper way can be generated.

To achieve the object, the invention is through the technical teaching of Claim 1 marked.

An essential feature of the invention is that in a transparent body almost mutually overlapping slats are arranged, the cross section of the Fill in the body in a step-like manner. Fractals, rising slats used.

The invention is therefore based on the finding that a transparent substrate is divided by a non-transparent lamella system, in such a way that that the substrate is transparent when looking at the substrate in a certain direction appears, meanwhile, when the viewing direction is changed, the non-transparent slat system is visible and a look through the Prevents substrate.

If the substrate is rotated under the eye with the same direction of view, Depending on the rotation, the substrate appears transparent or black, because in the case of Blackening the non-transparent slat system with its non-transparent Slats prevented a look through the substrate.

Depending on the rotation of the substrate, a light-dark effect is generated.

In a development of the invention it is provided that not every lamella on their Side edge forms a straight line, but that each slat is in a variety of Partial slats rising one after the other in steps, so that fractal lamellae are created, covering the cross section of the substrate to complete.

The division of the lamella system into fractal lamellae results in the advantage that the cover of the light-dark principle (see through. /. black) suddenly, d. H. the slats with a correspondingly high iteration level resolved, it is ensured that a rotation of this substrate sudden envelope of light-dark, d. H. from a graphic element to a other, is done. So in the ideal state there are no intermediate stages if there is one sufficiently high iteration level for the resolution of individual lamellae into fractals Bottom slats are made.

Above it was stated that with the arrangement of fractal lamellae such a transparent substrate can be such that it is during a total observation value of a certain observation angle of z. B. 90 ° appears completely transparent, and then there is a sudden change and from this angle of change the substrate no longer rotates with further rotation appears transparent.

So there are z. B. ideally an angle of 0 - 90 °, where the substrate is transparent appears, while at an angle from 91 ° to 180 ° the substrate only appears dark.

According to the present invention it is provided that not only a single one in such a transparent substrate Slat system is available, which ensures this light-dark envelope and is therefore able to provide light-dark information, but that in several lamella systems are present on this substrate, which interact.

As stated earlier, there is a range of 0 - 90 degrees where the first Slat system is transparent. If you now assign a second slat system the substrate so that in this area - where the first lamella system is open and appears transparent - the second slat system appears opaque, see above can use this viewing angle from 0 - 90 ° a total of two different graphic information is shown, namely the graphic information of the first slat system (which is bright) and in this bright state the graphic information of the second slat system appears dark when one through the substrate with a constant viewing angle of 0 - 90 ° through looks.

These lamella systems can be arranged side by side and / or one above the other his. They can overlap or exist in separate areas.

Above it was only stated that light-dark graphics are generated can, if it succeeds, subdivide a linear lamella into individual fractals To divide individual slats. It is obvious that with the present Invention not only light-dark information can be conveyed, but it can be provided that instead of dividing a single linear Line (single lamella) also a letter consisting of individual Lines can be divided fractally. This now leads to the fact that one first point of view through the transparent substrate z. B. the letter A in Interior of this substrate is visible and that with increasing rotation of the In a different viewing angle, the letter A suddenly disappears and the letter B appears.

This is only due to the overlap and the integration of two different lamella systems in the transparent substrate.

The lamella system according to the invention is suitable for use in transmitted light and / or incident light.

In the following, the invention will be explained using only one embodiment illustrative drawings explained in more detail. Here go from the drawings and their description further features and advantages of the Invention.

Figur 1:

schematisiert ein Substrat mit einer einfachen Lamellenanordnung bei nichtfraktaler Unterteilung;

Figur 2:

ein gegenüber Figur 1 abgewandeltes Substrat mit einer fraktalen Unterteilung von Lamellen;

Figur 3a:

die Darstellung eines durchgehenden Liniensegmentes, welches die Seitenkante einer Lamelle nach Figur 1 bildet;

Figur 3b:

die Unterteilung dieses Liniensegmentes der Lamelle nach Figur 3a unter einem ersten Winkel;

Figur 3c:

die Unterteilung der Linienzüge nach Figur 3b unter Verdoppelung dieses Winkels;

Figur 3d:

die Unterteilung des Linienzuges nach Figur 3c unter Verdreifachung des Winkels;

Figur 4:

schematisiert eine Darstellung des Hell-Dunkelumschlags bei Wechsel der Beobachtungsrichtung.

Show it:

Figure 1:

schematizes a substrate with a simple lamella arrangement with non-fractal subdivision;

Figure 2:

a modified substrate compared to Figure 1 with a fractal division of lamellae;

Figure 3a:

the representation of a continuous line segment, which forms the side edge of a lamella according to Figure 1;

Figure 3b:

the subdivision of this line segment of the lamella according to FIG. 3a at a first angle;

Figure 3c:

the subdivision of the lines according to FIG. 3b by doubling this angle;

Figure 3d:

the subdivision of the line according to FIG. 3c by tripling the angle;

Figure 4:

schematically shows the light-dark envelope when changing the direction of observation.

Figure 1 shows a substrate, i. H. thus a transparent body 2, the a total of three slats 6, 7, 8 (roughly spaced apart) shows. The body has two spaced-apart longitudinal sides 3 and In this case, the narrow sides 26 are arranged at a 90 ° angle. The body is further defined by an upper cover surface 4 and a lower cover surface 5 it is an approximately plate-shaped body 2, which should be transparent.

In the interior of the body there are now lamellae 6, 7, 8 which are parallel to one another arranged, which form gaps 12, 13 between them.

Each lamella is defined by a longitudinal edge 9 which is approximately parallel to the Longitudinal edge of the narrow sides 26 runs, and the rest of the surface of each runs Lamella 6-8 also parallel to the narrow sides 26 of this plate-shaped body. The narrow sides of each slat are each defined by a line segment 1, which runs approximately parallel to the narrow sides of the body.

If you now look through this transparent body in the direction of arrow 10, then can be seen through the spaces 12 between the slats 6, 7, 8 because the slats themselves are not visible in this direction and the body appears transparent.

However, if you look in the direction of arrow 11 (or in the opposite direction) to the Body 2, then the non-transparent slats 6, 7, 8 prevent a view through the body; the body appears black.

Depending on the viewing direction, light-dark information can be conveyed which depends on the position of the slats and their number, etc.

If one now divides a line segment 1 according to FIG. 3a into several line segments 1b according to FIG. 3b, this line segment 1 is then transformed.

The invention is based on the knowledge that (fractal) Let slat systems realize surprising projection properties. On fractal lamella system arises from the repeated application of a Transformation to a line segment 1 in Figure 3a. As an example shows 3d illustration of a slat system made by repeated division of a Line segment 1 in N-parts and rotation through an angle Θ arises. 3b to 3d show different iteration levels of the construction. Despite the ever finer Subdivision of the slats takes for the slat system required depth (D) not significantly. The slat system from Figure 3d is almost opaque for all angles between 0 ° and + 90 ° and for everyone Angles between 0 ° and -90 ° almost translucent (see Fig. 4). For one small angle Θ and a large N go the deviations from "opaque" and "translucent" with increasing iteration against Zero. Such fractal lamellae can be used to construct images that are in focus defined angles appear and disappear. It is mathematically proven that fractal lamella systems can be constructed, their parallel projection from every solid angle gives a desired image for this solid angle.

The lamella systems can be exposed, written, embossed in a substrate, extruded, mechanically generated (drilled) or realized in similar processes become. They can be viewed through or under supervision (Back lighting or reflection). By appropriate choice of The security feature can be colored in the colors of substrate and slats his.

• Verblüffender, klar verifizierbarer Effekt.
• Das ""Auslesen" der Struktur des Lamellensystems ist sehr schwierig.
• Das Nachstellen des Lamellensystems ist noch schwieriger.

Advantages of the invention over the prior art:

• Amazing, clearly verifiable effect.
• "" Reading "the structure of the lamella system is very difficult.
• Adjusting the slat system is even more difficult.

In a development of the present invention it is provided that several Layers of such lamella systems in layers of different depths of the substrate are and it is also provided that the angle-dependent graphic effect in the Transmitted light is visible.

It can also be provided in another embodiment that the angle-dependent graphic effect is visible in reflected light.

FIG. 2 now shows the application of the fractals shown in FIG. 3d Slats 14, 15, 16, 17 in a substrate according to Figure 2.

It can be seen there that the lamellae 14-17 form intermediate spaces 12, 13 are lined up closely and step-like and stair-like, with the Gaps 12, 13 allow a view through these fractal lamellae, when the body 2 in the area between the arrow directions 21-22 from above is looked at. In contrast, appears in the area between the arrow directions 11-22 the body 2 dark.

FIG. 3b also explains that the angle theta is provided with reference number 18 3c and the angle 19 is doubled compared to the angle 18, where however, the angle 20 in FIG. 3d is tripled compared to the angle 18.

In Figure 4 is shown schematically that depending on the Observation direction 23 there is a bright area 24 in the angular range from + 90 ° to 0 ° there and also a dark area 25 in the angular range from 0 ° to + 90 °.

With the given technical teaching you can very well Security features manufactured counterfeit-proof, because such Security features can very easily be found in value and security documents to get integrated. Such a transparent body can be in a window Section of such a value and security document can be arranged and can be viewed either in transmitted light or in reflected light.

drawing Legend

1.

Line segment 16

Second

body

Third

long side

4th

cover surface

5th

cover surface

6th

lamella

7th

lamella

8th.

lamella

9th

longitudinal edge

10th

Direction of arrow (direction of illumination)

11th

Arrow direction (dark area)

12th

gap

13th

gap

14th

fractal lamella

15th

fractal lamella

16th

fractal lamella

17th

fractal lamella

18th

angle

19th

angle

20th

angle

21st

Direction of arrow (bright area)

22nd

Direction of arrow (cover area)

23rd

direction of observation

24th

light area

25th

dark area

26th

narrow side

Claims (6)

1. Security feature for documents of value or security documents, comprising a transparent body (2) which is provided with devices which display graphical information according to the angle (18, 19, 20) between direction of illumination and direction of observation, these devices consisting of almost overlapping laminae (6-8; 14-17) which are arranged approximately in step formation in the body (2), characterised in that each of the laminae (6-8; 14-17) is further fractally divided into a plurality of stepped part-laminae or sub-laminae.
2. Security feature according to claim 1, characterised in that the laminae (14-17) and/or part-laminae or sub-laminae are arranged one behind the other in ascending order over the thickness (D) of the body (2).
3. Security feature according to one of claims 1 and 2 characterised in that a plurality of layers of laminae (14-17) are arranged one above the other in the body (2).
4. Security feature according to claim 3, characterised in that the layers of laminae (14-16) are at an angle to one another.
5. Method of making a security feature according to one of the preceding claims, with the following steps:

   preparation of a transparent body (2);

   imprinting a lamina structure in the body (2) along a line by light, embossing, coating or a mechanical treatment, an individual lamina being fractally divided into further part- or sub-laminae.
6. Method according to claim 5, characterised in that laser light is used.

Images