AU2010335588A1

AU2010335588A1 - Security element and method for the manufacture thereof

Info

Publication number: AU2010335588A1
Application number: AU2010335588A
Authority: AU
Inventors: Peter Franz
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient GmbH
Priority date: 2009-12-23
Filing date: 2010-12-15
Publication date: 2012-08-02
Anticipated expiration: 2030-12-15
Also published as: EP2516175A1; AU2010335588B2; EP2516175B1; DE102009060506A1; WO2011076361A1

Abstract

The invention relates to a security element for security papers, value documents or the like, comprising a substrate (2), which is at least partially transparent or translucent, a first printed image applied to the substrate (2), a second printed image applied to the substrate (2) and arranged beneath the first printed image at a predetermined distance therefrom, wherein the first printed image and the second printed image are each formed by means of line grids (5, 6), wherein at least one of the two line grids (5, 6) is modified on one side, the two line grids (5, 6) are aligned parallel with each other and the printed images and the line grids (5, 6) thereof are matched to each other in such a way that, when viewed in transmitted light, the line grids (5, 6) complement each other differently in dependence on the viewing angle.

Description

Security element and method for the production thereof [0001] The invention relates to a security element for security papers, value documents and the like, having a carrier that is at least partly transparent or translucent, a first printed image placed on the carrier and a second printed image placed on the carrier, the second printed image being arranged below the first printed image. [0002] The invention further relates to a value document having such a security element. [0003] The invention relates to a manufacturing method for a security element for security papers, value documents or the like, wherein a carrier is equipped with a first printed image and with a second printed imaged that lies below the first printed image. [0004] Objects to be protected are frequently fitted with a security element which permits verification of the authenticity of the object and at the same time serves as protection from unauthorized reproduction. [0005] Objects to be protected are for example security papers, identity documents and value documents (such as e.g. banknotes, chip cards, passports, identification cards, identity cards, shares, bonds, deeds, vouchers, checks, admission tickets, credit cards, health cards, ...) as well as product securing elements, such as e.g. labels, seals, packages. [0006] The forgery resistance of a security element is particularly high when the security element shows motifs which are perceivable in transmission and are positioned in a certain relation to each other and/or are hard to imitate or reproduce. [0007] In the state of the art there are many different approaches and means to make a security element forgery-resistant. From WO 2007/115656 A2 a security element is known which has a light-transmissive carrier material having on one side with a first periodical printed dot or line pattern and on a second side a second periodical printed dot or line pattern 2 which is substantially inverse thereto. WO 2008/098739 A2 describes a security element wherein the information items on the front side and on the back side complement each other. [0008] In the state of the art it is further known to print images through a line screen. WO 2004/020217 Al further develops this line screening so that the modulation is provided only at one edge of the lines. The opposite edge is smooth. Such a modulation is called a one-sided modulation of a line screen or a line screen modulated on one side. [0009] It is the object of the invention to create a security element that shows in good quality different motifs on the front side and on the back side, and a further motif upon viewing in transmitted light. [0010] This object is achieved by a security element for security papers, value documents or the like, having a carrier that is at least partly transparent or translucent, a first printed image placed onto the carrier, a second printed image placed onto the carrier, said second image lying in a different plane than the first printed image, whereby the first printed image and the second printed image are respectively formed by line screens, whereby at least one of the two line screens is modulated on one side, the two line screens are aligned parallel to each other, and the printed images and their line screens are coordinated with each other so that in transmission the line screens complement each other differently in dependence on the viewing angle. [0011] The object is further achieved by a value document having such a security element. [0012] The object is finally also achieved by a manufacturing method according to claim 8, wherein the line screens are coordinated with each other so that in transmission the line screens complement each other at a certain viewing angle so that a motif formed by one of the line screens is canceled out. [0013] The security element according to the invention achieves a tilt-effect with the aid of line screen structures which can be produced with a relatively simple print. Due to the one- 3 sided structuring of a line screen according to WO 2004/020217 Al, whose disclosure in this regard is hereby included in its entirety in this application, a shadowing or hiding of the motif that is structured with the one-sided line screening can be achieved in a simple fashion by tilting. It is therefore provided in a further development that the line screens are coordinated with each other so that in transmission the line screens complement each other at a certain viewing angle in such a fashion that a motif formed by the line screen structured on one side is canceled out. [0014] Of course also both line screens can be modulated on one side and configured so that in transmission they complement each other in dependence on the viewing angle to form at least two different motifs. Typographically it is preferred when both line screens have the one-sided modulation on the same side of their lines. [0015] The two line screens are aligned parallel to each other, so as to achieve the complementing of the line screens in dependence on the viewing angle according to the invention. Preferably the line screens also have the same spatial frequency transversally to the line direction. The viewing angle then changes the phase of the line screens in relation to each other and thus achieves the complementing that can also be a shadowing. The printed images lie in different planes. This can be achieved e.g. in that they are arranged on the upper side or the lower side of the carrier. [0016] Of course the screen structures can be placed or printed at a slight offset from each other; the function is guaranteed nevertheless. However, a preferably exact register (upper side/ lower side) is desirable. [0017] In practice it has turned out that a preferably great distance (e.g. through material strength) between the printed images is advantageous. However, effects can be achieved already starting at a distance of 20 pm. The best results were achieved with a distance of at least 70 pm.

4 [0018] A further possibility is the printing of two carrier layers which can be joined in the process step (e.g. card manufacture according to the "sandwich procedure"). [0019] A further possibility is to preprint one side conventionally and to apply images to the other side with a laser procedure, ink jet procedure, laser printing procedure. This permits a personalization. [0020] The implementation of the printed images can generally take place as a number, digit, ornamentation, pictorial representation, also portrait, and a combination thereof. [0021] The invention makes it possible to recognize two motifs in alternation by tilting the carrier. [0022] The manufacturing method can also be executed in several stages, so as to achieve an individualization of a security element. For this purpose it is possible to perform the one sided modulation of at least one line screen only after the print, for example by action of suitable laser radiation. The manufacturing method thus first produces a precursor of the security element, on which, to conclude the manufacturing process, there is executed a one sided modulation of at least one line screen to individualize the security element. [0023] The sequence of the application of the line screen and of the production of the half sided modulation can consequently be adjusted to the respective framework conditions, in particular the modulation does not have to take place upon printing the line screen, but can also be configured subsequently. [0024] The printed images can have different colors, in particular the print can be executed in color, with different colors, whereby the first and the second printed image can be varied differently. [0025] In addition to the printed images further elements representing patterns or images can be provided, which can be executed areally or so that they are adjusted to the line screens. In 5 this fashion for example the attention of a viewer can be diverted, upon viewing in plan view, from the tilting information itself, which is then perceived only upon tilting. [0026] The security element further has the advantage that its characterizing structure is recognizable for a viewer without any aids. [0027] The modulated line screens can preferably be realized with a line strength of between 20 pm and 200 pm, particularly preferably between 50 pm and 150 pm. [0028] The security element can be configured in particular as a security thread, tear thread, security band, security strip, patch or as a label for application to a security paper, value document or the like. In particular, the security element can span transparent regions or recesses. [0029] The term security paper is understood here to be in particular the not yet circulable precursor to a value document, which can have besides the security element of the invention for example also further authentication features (such as e.g. luminescent substances provided within the volume). Value documents are understood here to be, on the one hand, documents manufactured from security papers. On the other hand, value documents can also be other documents and objects that can be equipped with the security feature of the invention in order for the value documents to have uncopiable authentication features, thereby making it possible to verify authenticity and at the same time preventing unwanted copies. [0030] Translucence or translucent is understood in this description as the partial light transmission of a body, thus the characteristic of letting light pass without being transparent. Consequently, translucence has to be seen delimited from transparency (= image permeability or visual permeability). The reciprocal property of translucence is opacity. In the sense of this description a body is translucent or transparent when the transmittance in the range of visible optical radiation (= light) amounts to at least 90%. In the case of transmittances between 10% and 90% the body is partly transparent or translucent and in the case of a transmittance of less than 10% opaque.

6 [0031] An at least partly transparent or translucent body according to the invention consists for example of paper of cotton fibers or other natural fibers or of synthetic fibers, i.e. a blend of natural and synthetic fibers. Further, the body can consist of a foil or plastic foil or a foil composite or of a composite of at least a paper layer covered on both its surfaces by at least a foil or plastic foil and/or at least a lacquer layer. It can also be a card body. [0032] The manufacturing method according to the invention can be developed in such a fashion that the described preferred variants and embodiments of the security element are manufactured. [0033] It is evident that the features mentioned above and those to be explained hereinafter are usable not only in the stated combinations, but also in other combinations or in isolation, without going beyond the scope of the present invention. [0034] In the following the invention is explained in more detail by way of example with reference to the accompanying figures that also disclose essential features of the invention. The figures are described as follows: [0035] Fig. 1 a schematic perspective view of a security element, [0036] Fig. 2 a representation similar to Fig. I to illustrate the effect of the security element of Fig. 1, [0037] Fig. 3 in three partial figures different views at different viewing angles of the security element of Fig. 1, [0038] Fig. 4 two partial figures to explain the function of a further embodiment of the security element, 7 [0039] Fig. 5 and Fig. 6 show figures to illustrate an individualization of a security element, similar to that of Fig. 1. [0040] For the sake of improved representability, the figures are all represented not true to scale, in particular with reference to thicknesses. Moreover, elements that are functionally and/or structurally equal or consistent bear the same respective reference numeral in all figures so as to prevent repetitions of the description. In the subsequent description of section positions the side that lies on top in the representation of Fig. I is referred to as front side or upper side of the security element. The back side is correspondingly the side lying on the bottom. This convention merely serves to simplify the description and is not meant as a limitation regarding the structure and/or application of the security element. [0041] Fig. I shows a simplified perspective view of a security element 1. The basis for the security element I is a carrier 2, which can be realized for example by a plastic foil. This plastic foil is configured transparent or even only translucent, as will be explained below. The security element 1 can be provided for example for a banknote. In particular it can be arranged partly above a window provided in the banknote. [0042] On the upper side 3 of the security element 1 a printed layer is disposed. The same is valid for the lower side 4. The printed layer on the upper side 3 represents e.g. a first motif obtained by line screening. Thus on the upper side 3 a first line screen 5 is disposed. On the lower side 4 there is also printed a second line-screened motif which is formed by a second line screen 6. Both line screens are configured as line screens modulated on one side, i.e. the information modulation of all lines is present only at one edge, whereas the other edge is not modulated. In the simplified representation of Fig. 1 the modulation is achieved by graduated structures. Other structurings are possible likewise, such as for example waves, curves or circular structures. [0043] Fig. 2 shows that the two line screens complement each other differently in dependence on the respective viewing angle of a viewer 7. The line screens 5 and 6, which extend parallel, shift perpendicularly to the longitudinal direction of the lines through tilting 8 the carrier 2 or through a corresponding change of the viewing angle. In Fig. 2 different viewing directions A, B and C are entered exemplarily. Each viewing directions effects a different phase of the parallel extending line patterns. The result of this phase shift is shown in Fig. 3 in three partial images which are allocated to the corresponding viewing angles of Fig. 2. When viewed from the viewing direction A the line screens complement each other so that the modulation is determined exclusively by the line screen 5, since only the modulated edge of said line screen is visible. The other edge of the line screen 6 is covered. For the sake of better recognizability Fig. 3 shows views of the security element 2 from the lower side. [0044] In the case of viewing direction B the modulated edge of the line screen 5 is almost completely covered, and in the case of viewing direction C the line screens are shifted against each other in such a fashion that merely the modulated edge of the line screen 6 is recognizable. In contrast, the modulated edge of the line screen 5 is covered. [0045] Fig. 3 shows clearly that the use of a line screen modulated on one side is essential for the tilt effect. In the case of a two-sided modulation, which is actually usual in the state of the art, and which would also be desirable in terms of contrast, there would be no such state as viewing angle A or at the viewing angle B, in which the modulated information of one line screen is completely visible, although its other edge is covered. Due to the one-sided modulation of the line screens, wherein one edge of the lines is always executed smoothly, i.e. not modulated, the covering of individual line edges is not harmful. [0046] Fig. 4 shows that the described concept can also be used for shadowing. When a line screen, in the example the line screen 5, is not modulated, there results, in dependence on the viewing angle, a complete covering of the modulated edge of the other line screen. This state is represented in the left partial figure of Fig. 4. From a different viewing direction, which can be seen in the right partial figure, in contrast the unmodulated line screen 5 is shifted in relation to the modulated line screen 6 in such a fashion that the modulated edge of the line screen 6 is visible. The motif coded thereby is thus recognizable. As a result one obtains a shadow image that is easy to manufacture and visible only at a certain viewing angle.

9 [0047] Figures 5 and 6 illustrate that the manufacture of the described security element can also take place in two stages. This permits an individualization of the security element. For this purpose at least one of the two line screens is executed without modulation. The other line screen can optionally be equipped with a modulation. This state is represented in Fig. 5, in which the line screen 6 is for example modulated so that the printed image represents the portrait of the owner of an identification card. The line screen on the other side of the carrier is not modulated, however. The right partial figure of Fig. 5 shows an unstructured line screen 5a for this reason. This line screen 5a, as illustrated by Fig. 6, can now be structured in a processing step 8 so as to provide a further information item in the form of an individualization. As a result a structured line screen 5b is obtained. Expediently the motifs of the line screen 6 and of the individualized line screen 5b complement each other, for example the line screen 5b can code an identification card number, and the line screen 6 shows the image of the holder of the identification card. [0048] For the manufacturing process of the described security element a good registration between the line screens 5 and 6 is desirable. All printing methods suitable for this purpose come into question for the manufacture, in particular offset printing method, super simultaneous printing method, ink-jet printing method, laser printing method, etc. [0049] Of course the printing of the line screens can be executed in color, in particular for the line screens 5 and 6 different colors can be used. [0050] Alternatively or additionally at least one of the line screens 5, 6 can also be produced completely by lasering, in that a laser acts on the corresponding side of the carrier 2 and changes it in such a fashion that the line screen becomes visually recognizable. This can be employed preferably in the case of passports or identification cards, wherein an individual information item, for example a signature or an image, is incorporated in or on certain layers, which are preferably equipped with materials absorbing the laser beams. In this fashion e.g. the two sides of a card body acting as carrier can be lasered accordingly.

10 [0051] Also the removal of a printed layer that was applied as preprint absorbing the laser radiation, or a doping changed by means of laser radiation is possible. [0052] The carrier 2 merely has to fulfill the requirement that it shows a certain degree of transparency or translucence. When a transparent carrier 2 is used, the motif appears particularly clearly upon viewing in transmitted light, however also a translucent carrier can be sufficient. [0053] The substrate used can in particular consist of one or several layers and can also have suitable coatings. Printing, bonding, lining, laminating or other surface treatments are possible. The printed documents can at least partly also lie within one substrate. It is essential only that they lie in spaced-apart planes. [0054] Of course the security element according to the invention can also be combined with other security features, so as to achieve a better protection from imitation or copying.

11 List of reference signs I security element 2 carrier 3 upper side 4 lower side 5, 5a, 5b first line screen 6 second line screen 7 viewing 8 processing step

Claims

1. A security element for security papers, value documents or the like, having - a carrier (2) that is at least partly transparent or translucent, - a first printed image placed onto the carrier (2), - a second printed image that is placed onto the carrier (2) and arranged at a predetermined distance below the first printed image, characterized in that - the first printed image is formed by a line screen (5) and the second printed image is formed by a line screen (6), whereby at least one of the two line screens (5, 6) is modulated on one side, - the two line screens (5, 6) are aligned parallel to each other and - the printed images and their line screens (5, 6) are coordinated with each other so that in transmission the line screens (5, 6) complement each other differently in dependence on the viewing angle.

2. The security element according to claim 1, wherein the line screens (5, 6) are coordinated with each other so that in transmission the line screens (5, 6) complement each other at a certain viewing angle (A, B, C) so that a motif formed by one of the line screens (5, 6) is canceled out.

3. The security element according to claim 1, wherein the two line screens (5, 6) are modulated on one side and in transmission complement each other to form at least two different motifs in dependence on the viewing angle, whereby both line screens (5, 6) have the one-sided modulation preferably on the same side.

4. The security element according to claim 1, 2 or 3, wherein the two line screens (5, 6) have different colors. 13

5. The security element according to any of the preceding claims, whereby the carrier (2) is at least 20 pm thick, preferably at least 70 pm thick.

6. The security element according to any of the preceding claims, whereby the first printed image is placed onto an upper side (3) and the second printed image is placed onto a lower side (4) of the carrier (2).

7. A value document or card body having a security element (1) according to any of the claims I to 5.

8. A manufacturing method for a security element for security papers, value documents or the like, wherein - a carrier (2) is equipped with a first printed image and a second printed image, whereby the second printed image is arranged at a predetermined distance below the first printed image, characterized in that - the first printed image is formed by a line screen (5) and the second printed image is formed by a line screen (6), whereby at least one of the line screens (5, 6) is modulated on one side, - the two line screens (5, 6) are aligned parallel to each other and - the printed images and their line screens (5, 6) are coordinated with each other so that in transmission the line screens (5, 6) complement each other differently in dependence on the viewing angle.

9. The manufacturing method according to claim 8, wherein the line screens (5, 6) are coordinated with each other so that in transmission the line screens (5, 6) complement each other at a certain viewing angle so that a motif formed by one of the line screens (5, 6) is canceled out.

10. The manufacturing method according to claim 9, wherein both line screens (5, 6) are modulated on one side and in transmission complement each other in dependence on the 14 viewing angle to form at least two different motifs, whereby both line screens (5, 6) have the one-sided modulation preferably on the same side.

11. The manufacturing method according to any of the claims 8 to 10, wherein both line screens (5, 6) have different colors.

12. The manufacturing method according to any of the claims 8 to 11, whereby the first printed image is applied to a first carrier layer and the second printed image is applied to a second carrier layer and the two carrier layers are subsequently joined to form the carrier (2).

13. The manufacturing method according to any of the claims 8 to 11, whereby the first printed image is placed onto an upper side (3) and the second printed image is placed onto a lower side (4) of the carrier (2).