EP4624185A1

EP4624185A1 - Data carrier and method of producing it

Info

Publication number: EP4624185A1
Application number: EP24305462.4A
Authority: EP
Inventors: Jukka Möksy; Manu Nurminen
Original assignee: Thales DIS France SAS
Current assignee: Thales DIS France SAS
Priority date: 2024-03-27
Filing date: 2024-03-27
Publication date: 2025-10-01
Also published as: WO2025202167A1

Abstract

A data carrier (1) for a secure article comprises a carrier body (2), and at least one security element (3) being provided on the carrier body (2). The security element (3) comprises at least one image (4) and at least one surface structure (5). The image (4) comprises at least one primary image (6) and at least one secondary image (7) being encoded in the primary image (6). The surface structure (5) comprises at least primary surface structure elements (8) and secondary surface structure elements (9). The image (4) is at least partially printed onto the primary surface structure elements (8). At least the secondary surface structure elements (9) are configured to decode the secondary image (7) when the data carrier (1) is viewed under different viewing angles (α) and/or illuminated under different illumination angles (β), whereby the secondary image (7) becomes observable.

Description

TECHNICAL FIELD

The present invention relates to a data carrier according to claim 1, to a secure article comprising or consisting of such a data carrier according to claim 14, and to a method of producing such a data carrier according to claim 15.

PRIOR ART

Data carriers for secure articles such as passports generally comprise security elements such as an image of the document holder or other holder data such as a name, date of birth, etc. These security elements are often provided as a print such as an inkjet print on a surface of the data carrier. In such a case, the security element may easily be tampered by removing and replacing it by fraudulent data or by partially altering it. In order to improve a counterfeit protection, the data carrier can comprise a security element in the form of a surface structure with a print comprising encoded data hidden in the print, and wherein the surface structure can decode the hidden data. The design of the decoding surface structure is one of the key points of such security elements. It strongly affects the functionality of the security element, in particular the quality of the decoding, and thus the counterfeit protection.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a data carrier comprising a security element that provides an increased security against forgery.
This object is achieved with a data carrier according to claim 1. That is, a data carrier for a secure article such as a passport is provided, wherein the data carrier comprises a carrier body, and at least one security element being provided on the carrier body. The security element comprises at least one image and at least one surface structure. The image comprises at least one primary image and at least one secondary image being encoded in the primary image. The surface structure comprises at least primary surface structure elements and secondary surface structure elements. The image is at least partially printed onto the primary surface structure elements. At least the secondary surface structure elements are configured to decode the secondary image when the data carrier is viewed under different viewing angles and/or illuminated under different illumination angles, whereby the secondary image becomes observable.
That is, the security element is formed by an image being printed on the surface structure, i.e. the image is a print. To this end it is particularly preferred that the print comprises or consists of ink and/or is an inkjet print being printed onto the surface structure with an inkjet printer.
There are two main aspects to consider with such security elements. Firstly, a visual look of the print when the data carrier is viewed under the normal viewing angle, i.e. at 90° with respect to a surface plane of the data carrier, and the decoding effectiveness of the encoded secondary image while tilting the data carrier, i.e. while viewing the data carrier under different viewing angles, and/or while illuminating the data carrier under different illumination angles. Preferably, the visual look of the image under a normal viewing angle is as natural as possible under normal lighting conditions, i.e. in the absence of an illumination with light from a light source such as a lamp, flashlight, laser or the like, wherein the encoded secondary image is essentially unobservable. At the same time, it is furthermore preferred that the viewing angle required for the decoding to happen is reasonably large. If the viewing angle required to decode the secondary image is small such as close to 0° with respect to the surface plane of the data carrier or, in other words, essentially along the surface plane of the data carrier, the functionality of the security element is not very good, since it requires a lot of effort from the user to get the desired effect visible. That is, the lower a height of the surface structure is, e.g. the less the surface structure extends from the carrier body, the smaller the viewing angle being required for the decoding of the secondary image. In other words, the user needs to tilt the data carrier more in order to see the encoded secondary image. A bigger height of the surface structure in this regard is therefore beneficial for the effect. However, when the height of the surface structure increases, a printing surface of the surface structure, i.e. a surface of the surface structure on which the image is printed, becomes very steep such that the print, e.g. the ink constituting the print, flows down the surface structure resulting in a poor image quality.
The present invention is based on the insight that the quality of the image as well as the decoding capabilities can be improved by a surface structure comprising at least primary surface structure elements and secondary surface structure elements, wherein the image is at least partially printed onto the primary surface structure elements, and wherein at least the secondary surface structure elements are configured to decode the secondary image. The viewing angle under which the data carrier is viewed refers to the angle being enclosed between a viewer of the data carrier and a (fictitious) surface plane of the carrier body that extends along a surface of the carrier body on which the security element is provided.
Said surface of the carrier body preferably is a top surface of the carrier body that preferably furthermore corresponds to a top surface of the data carrier.
Hence, a viewing angle of 90° corresponds to a normal viewing angle or, in the event of the top surface of the carrier body providing the top surface of the data carrier, a top view of the data carrier.
The Illumination angles under which the data carrier is illuminated is likewise understood as the angle being enclosed between a source of illumination of the data carrier and said (fictitious) surface plane of the carrier body. Various sources of illumination are conceivable, for instance a lamp, a flashlight, a laser, etc. Thus, ain illumination angle of 90° corresponds to an illumination of the data carrier from the top, i.e. perpendicular to the top surface of the carrier body or the top surface of the data carrier, respectively. An illumination angle of 0° can be seen as an illumination of the data carrier in sidelight.
The primary surface structure elements are preferably configured to reflect light such, that the secondary image is decoded when the data carrier is viewed under different viewing angles and illuminated under different illumination angles.
Additionally or alternatively, the primary surface structure elements are preferably configured to at least partially block impinging light such, that the primary surface structure elements participate in the decoding of the secondary image when the data carrier is illuminated under different illumination angles, preferably under one or more illumination angles being smaller than 25°.
Hence, the present invention provides different decoding mechanisms that enable a decoding of the secondary image or making the secondary image observable, respectively.
Namely, a decoding can take place based on a viewing of the data carrier under different viewing angles such as tilting the data carrier. In this case secondary surface structure elements and, depending on their configuration, also the primary surface structure elements enable a decoding by i) hiding or visually blocking and thus keeping encoded and ii) unravelling or visually unblocking und thus making observable the secondary image. In other words, the primary surface structure elements are preferably configured to at least partially block impinging light such, that the primary surface structure elements participate in the decoding of the secondary image when the data carrier is illuminated under different illumination angles, preferably under small illumination angle such as under one or more illumination angles being smaller than 25°. Again in other words, the surface structure is preferably configured such, that an illumination from a small angle such that at least the secondary surface structure elements perform as light blocker and possibly additionally with a participation of the primary surface structure elements in said light blocking result in a decoding of the secondary image. For instance, the slopes of the primary surface structure elements could add to the blocking effect provided by the secondary surface structure elements. That is, also the primary surface structure elements can be configured to participate in the decoding of the secondary image. For instance, the data carrier can be configured such that the secondary surface structure elements perform as light blocker, and wherein the slopes of the primary surface structure elements can add to this effect.
Additionally or alternatively, an illumination of the data carrier under different illumination angles may enable a decoding by illuminating or keeping encoded by keeping in shade the secondary image. For example, an illumination of the data carrier with sidelight, i.e. an illumination along a small illumination angle such as an illumination angle of 0° to 10°, could unravel the secondary image in light versus keeping it in shade. Hence, in a sense, this type of decoding the secondary image can be seen as generating an illumination effect between the secondary image being kept in shade and in light.
Additionally or alternatively, an illumination of the data carrier under different illumination angles as well as a viewing of the data carrier under different viewing angles may enable a decoding by generating reflected light being reflected from the secondary surface structure elements and possibly additionally also from the primary surface structure elements, and wherein said reflected light determines what is seen/hidden as a contrast difference among the secondary surface structure elements and possibly also among the primary surface structure elements. Hence, this type of decoding the secondary image can be seen because of a contrast effect. In other words, the primary surface structure elements are preferably configured to reflect light such, that the secondary image is decoded when the data carrier is viewed under different viewing angles and illuminated under different illumination angles. Again in other words, the surface structure is preferably configured such, that a combination of lighting and viewing angles result in a specular reflection from the primary surface structure elements,
This shall be exemplified with a surface structure comprising primary surface structure elements being saw-tooth-like or having a zig-zag shape, respectively, that is provided by ridges that alternatingly extend away from the surface of the carrier body and towards the surface of the carrier body. In this example, the secondary surface structure elements are protrusions that protrude from the tips of the saw-tooth-like or zig-zag shape. Hence, said surface structure enables a decoding of the secondary image via a contrast effect, wherein light reflected from the surface structure determines what is seen/hidden as a contrast difference between two slopes of the saw shape or zig-zag shape, which depends mainly on the illumination angles and the viewing angles. In addition, the secondary surface structure elements enable a decoding via hiding or visually blocking and thus keeping encoded and unravelling or visually unblocking the secondary image. In a sense, the primary surface structure elements and the secondary surface structure elements can be said to perform in this example two different roles in the decoding, with the primary surface structure elements being more relevant for decoding based on an illumination of the data carrier from different illumination angles, and the secondary surface structure elements being more relevant for a decoding based on different viewing angles such as tilting the data carrier.
Thus, the surface structure according to the invention can decode the secondary image not only via one of the described effects, but via two or more of the described effects. To this end not only the secondary surface structure elements serve the purpose of decoding, but also the secondary surface structure elements can participate in the decoding.
In any case it is preferred that the primary image is observable when the data carrier is viewed under at least a first viewing angle and a second viewing angle and/or when the data carrier is illuminated under at least a first illumination angle and a second illumination angle, and wherein the secondary image is preferably hidden when the data carrier is viewed under the first viewing angle and/or when the data carrier is illuminated under the first illumination angle but observable when the data carrier is viewed under the second viewing angle and/or when the data carrier is illuminated under the second illumination angle.
The secondary surface structure elements are preferably configured to decode the secondary image when the data carrier is viewed under viewing angles being 20° or more, preferably 35° or more such as about 45°.
The primary image and the secondary image are preferably observable to an un-aided eye, and/or the security element preferably is self-verifying.
The security element, in particular the primary image and/or the secondary image, is preferably configured to exhibit different appearances when the data carrier is viewed under different viewing angles and/or illumination angles, and wherein the different appearances are preferably at least one of a different luminescence, different colour, different intensity, different brightness, or different reflectance.
The primary image and/or the secondary image preferably are at least one of:

a picture and/or an alphanumeric character such as a name, date of birth, country of residence, coat of arms or the like, and/or
machine readable.

The image, in particular the primary image and the secondary image, is preferably essentially entirely printed onto the primary surface structure elements. Additionally or alternatively, the secondary surface structure elements are preferably essentially free from the print.
That is, the surface structure preferably comprises the image only on certain regions, namely on the primary surface structure elements, whereas the secondary surface structure elements are preferably free from the print, i.e. from the image.
The image being essentially entirely printed onto the primary surface structure elements means that the entire image is printed onto the primary surface structure elements apart from some part of the print and/or pixels that do not participate in the decoding effect, i.e. a 'passive part' of the print, can happen to be on the secondary surface structure elements.
The surface structure can extend from a top surface of the carrier body. Alternatively, the surface structure can at least partially be arranged offset inwards with respect to a top surface of the carrier body in the direction of an interior of the carrier body.
That is, the surface structure, in particular the primary surface structure elements and the secondary surface structure elements, can extend from a top surface of the carrier body away from said top surface and project towards an outside of the carrier body and thus of the data carrier. A (fictitious) surface plane running along the surface structure is preferably congruent with a (fictitious) surface plane running along the top surface of the carrier body.
However, it is likewise conceivable that the surface structure is at least partially arranged offset inwards with respect to the top surface of the carrier body in the direction of an interior of the carrier body. In other words, the surface structure can be arranged at least partially below the top surface of the carrier body.
In particular, the surface structure can be entirely arranged offset inwards, wherein the primary surface structure elements and the secondary surface structure elements are arranged offset inwards with respect to the top surface of the carrier body. Alternatively, the surface structure can be only partially arranged offset inwards, wherein part of the surface structure still projects from the top surface of the carrier body. For example, the primary surface structure elements can be arranged offset inwards whereas the secondary surface structure elements can be projecting outwards.
In other words, the surface structure can be arranged completely above, partially above (or partially below), or completely below the top surface of the carrier body.
A maximal height of the secondary surface structure elements with respect to a reference plane running parallel to a surface plane of the carrier body is preferably larger than a maximal height of the primary surface structure elements with respect to said reference plane of the carrier body. Additionally or alternatively, the secondary surface structure elements are preferably configured to protect the primary surface structure elements and/or the image from wear.
That is, a maximal height of the secondary surface structure elements with respect to a reference plane running parallel to a surface plane of the carrier body is larger than a maximal height of the primary surface structure elements with respect to said reference plane of the carrier body. In other words, an absolute maximal height of the secondary surface structure elements with respect to a reference plane is preferably larger than an absolute maximal height of the primary surface structure elements with respect to said reference plane. The surface plane of the carrier body preferably runs parallel to the top surface of the carrier body.
With reference to an x,y,z-coordination system a three-dimensional extension of the surface structure can be expressed as follows: x and y horizontal and vertical coordinates of the surface structure that span a plane being parallel to the surface plane of the carrier body, and z is the direction perpendicular to the surface plane. As mentioned above, the surface structure could entirely extend or project from the top surface of the carrier body or be entirely embedded into the carrier body, i.e. being arranged offset inwardly or anything in between. In any of these cases, an extension of the surface structure, in particular of the secondary surface structure elements, along the z-direction preferably is in the range of 10 micrometer to 100 micrometer.
For instance, in the event of a partially embedded surface structure such as the primary surface structure elements being arranged offset inwardly and only the secondary surface structure elements projecting from the top surface of the carrier body, a maximal height of the secondary structure compared to the top surface of the carrier could be about 20 micrometer. In this case the primary structure elements could be arranged offset inwardly by about 45 micrometer with respect to the top surface of the carrier body.
In any case, the secondary surface structure elements are preferably configured to protect the primary surface structure elements and/or the image from wear. That is, the secondary surface structure elements preferably increase a wear resistance of the security element. In fact, the secondary surface structure elements having a larger absolute maximal height than the primary surface structure elements can be seen as a protective buffer for the primary surface structure elements and/or the print, e.g. when the surface structure is rubbed against a table, wallet etc., it's the secondary surface structure elements being in contact with the table, wallet, etc., but not the primary surface structure elements or the print itself.
An angle of inclination between a reference plane of the carrier body and a reference plane of the primary surface structure elements is preferably 45° or less, the angle of inclination particularly preferably being about 25° or particularly preferably being 10° or less such as about 0°. Additionally or alternatively, an angle of inclination between a reference plane of the carrier body and a reference plane of the secondary surface structure elements preferably is 45° or more, particularly preferably 80° or more such as about 90°.
The reference planes of the primary surface structure elements preferably extend along surfaces of the primary surface elements. Likewise, the reference planes of the secondary surface structure elements preferably extend along surfaces of the secondary surface elements.
According to a first aspect, the angle of inclination between the reference plane, in particular the surface plane of the carrier body, and the reference plane of the primary surface structure elements preferably is about 25°. For instance, the primary surface structure elements can have a saw-tooth-like or zig-zag shape being provided by ridges that alternatingly extend away from the surface of the carrier body and towards the surface of the carrier body.
However, according to a second aspect it is preferred that the angle of inclination between the reference plane, in particular the surface plane, of the carrier body and the reference plane of the primary surface structure elements is 10° or less such as 5 ° or less, preferably about 0°. In other words, the primary surface structure elements are preferably essentially flat or flat. Again in other words, the primary surface structure elements preferably extend essentially parallel or parallel to the surface of the carrier body.
The primary surface structure elements are preferably provided by the surface of the carrier body and are particularly preferably an integral part of the carrier body.
That is, according to this second aspect the surface structure is preferably configured such that the printing surface is essentially flat and thus being optimal for printing the image, while the decoding capabilities are still provided because of the provision of the secondary surface structure elements.
According to the first and second aspect, the angle of inclination between the reference plane or surface plane of the carrier body and the reference plane of the secondary surface structure elements is 45° or more, for instance 55° or more such as about 60°.
For example, the secondary surface structure elements can extend essentially at right angles with respect to the surface of the data carrier.
According to the first and second aspect, it is preferred that an angle of inclination between the surface planes of the secondary surface structure elements and the surface plane of the data carrier is preferably larger than the angle of inclination between the surface planes of the primary surface structure elements and the surface plane of the data carrier, such as two times larger or more.
According to the first and second aspect, the secondary surface structure elements preferably have an elongated shape such as an essentially rectangular, conical, elongated trapezoidal or cylindrical shape.
According to the first aspect, at least one secondary surface structure element preferably protrudes from a primary surface structure element.
To this end it is conceivable that one secondary surface structure element is provided per primary surface structure element, wherein said secondary surface structure element is preferably provided at a location of maximal height of the primary surface structure elements.
As mentioned earlier, the primary surface structure elements can have a saw-tooth-like or zig-zag shape, and wherein the secondary surface structure elements can protrude from the tips of the saw-tooth-like or zig-zag shape. Said tips are at locations of maximal height of the primary surface structure elements. Phenomenologically speaking, the secondary surface structure elements can be arranged on top of each primary surface structure element having a saw-tooth like or zig-zag shape.
However, it is likewise conceivable that two or more secondary surface structure elements are provided per primary surface structure element. For example, one of the surface structure elements can still be provided at a location of maximal height of the primary surface structure element such as at the tip of the saw-tooth or the zig-zag, wherein one or more other secondary surface structure elements are arranged before and/or after said primary surface structure element when seen along the extension direction of the surface structure, for example on each slope of the saw-tooth shape or zig-zag shape.
In any case it is preferred that the secondary surface structure elements are preferably thinner than the primary surface structure elements. That is, an area expansion of the secondary surface structure elements is preferably smaller than an area expansion of the primary surface structure elements when the surface structure is seen in cross-section.
Moreover, a height with which the secondary surface structure elements extend from the primary surface structure elements is preferably 25 % or less, more preferably 15 % or less such as 5 % or less of a maximal height of the primary surface structure elements.
Hence, according to the first aspect the primary surface structure elements can be kept at a reasonably low height that minimizes or even prevents a flowing of the image or of the ink constituting the image. In other words, a printing surface can be kept relatively flat. At the same time, the decoding capabilities are enhanced because of the provision of the secondary surface structure elements.
According to the second aspect, when seen along the extension direction of the surface structure, successive primary surface structure elements are preferably separated from one another via a secondary surface structure element. Additionally or alternatively, when seen along the extension direction of the surface structure, primary surface structure elements and secondary surface structure elements are preferably arranged in an alternating manner.
That is, in the second aspect it is preferred that no secondary surface structure elements are arranged on the primary surface structure elements.
According to the first and second aspect,
when seen along an extension direction of the surface structure, the primary surface structure elements are preferably arranged at a distance from one another and/or the secondary surface structure elements are preferably arranged at a distance from one another.
That is, when seen along the extension direction of the surface structure, the primary surface structure elements are preferably not immediately adjacent to each other, i.e. they are preferably not touching each other, and/or the secondary surface structure elements are preferably not immediately adjacent to each other, i.e. they are preferably not touching each other.
According to the first aspect and in the event of one secondary surface structure element being arranged per primary surface structure element, a distance between successive primary surface structure elements preferably is in the range of 100 micrometer to 500 micrometer, for instance in the range of 150 micrometer to 250 micrometer, such as about 200 micrometer, when seen along the extension direction of the surface structure. A distance between successive secondary surface structure elements preferably is in the range of 100 micrometer to 500 micrometer, for instance in the range of 150 micrometer to 250 micrometer, such as about 200 micrometer, when seen along the extension direction of the surface structure.
According to the first aspect and in the event of two or more secondary surface structure elements per primary surface structure element, a distance between successive primary surface structure elements preferably is in the range of 100 micrometer to 500 micrometer, for instance in the range of 150 micrometer to 250 micrometer, such as about 200 micrometer when seen along the extension direction of the surface structure. A distance between successive secondary surface structure elements preferably is in the range of 10 micrometer to 200 micrometer such as in the range of 25 micrometer to 100 micrometer, for instance about 45 micrometer when seen along the extension direction of the surface structure.
According to the second aspect, that is, no secondary surface structure elements are arranged on the primary surface structure elements, a distance between successive primary surface structure elements preferably is in the range of 100 micrometer to 500 micrometer, for instance in the range of 150 micrometer to 250 micrometer, such as about 200 micrometer when seen along the extension direction of the surface structure. A distance between successive secondary surface structure elements preferably is in the range of 100 micrometer to 500 micrometer, for instance in the range of 150 micrometer to 250 micrometer, such as about 200 micrometer when seen along the extension direction of the surface structure.
Said distance between successive primary surface structure elements when seen along the extension direction of the surface structure is referred to as primary-surface-structure pitch and said distance between successive secondary surface structure elements when seen along the extension direction is referred to as secondary-surface-structure pitch.
In any case, i.e. according to both aspects, a shape of the primary surface structure elements can be the same or different from a shape of the secondary surface structure elements.
For instance, and as mentioned earlier, the primary surface structure elements can have a saw-tooth-like or zig-zag shape or can be flat while the secondary surface structure elements can have an elongated shape such as an essentially rectangular, conical, elongated trapezoidal or cylindrical shape. However, it is likewise conceivable that the secondary surface structure elements have a saw-tooth-like or zig-zag shape as well. For example, the primary surface structure elements and the secondary surface structure elements could both have a saw-tooth-like shape, with that of the secondary surface structure elements being narrower. Other shapes of the primary surface structure elements and the secondary surface structure elements are of course likewise conceivable.
In any case, among the primary surface structure elements, a shape of the primary surface structure elements can be the same or different from one another. In any case, among the secondary surface structure elements, a shape of the secondary surface structure elements can be the same or different from one another. For example, a surface area of and/or a slope of the primary surface structure elements and/or of the secondary surface structure elements can remain constant or can change with respect to the extension direction of the surface structure.
In any case, the primary surface structure elements can be arranged in a regular or irregular manner with respect to the extension direction of the surface structure. In any case, the secondary surface structure elements can be arranged in a regular or irregular manner with respect to the extension direction of the surface structure. Being arranged in a regular manner with respect to the extension direction is understood as being arranged equidistantly, i.e. a distance between successive primary surface structure elements or between successive secondary surface structure elements remains constant when seen along the extension direction of the surface structure. Consequently, being arranged in an irregular manner with respect to the extension direction is understood as being irregularly spaced from one another when seen along the extension direction of the surface structure.
In any case, the primary surface structure elements and the secondary surface structure elements can be a single-piece element, i.e. formed from one piece and/or being an integral part.
Moreover, the primary surface structure elements when seen along an extension direction of the surface structure are preferably associated with a primary-surface-structure pitch and the secondary surface structure elements when seen along the extension direction of the surface structure are associated with a secondary-surface-structure pitch. At least in regions, a primary pitch being associated with the primary image when seen along the extension direction of the surface structure preferably matches or mismatches the primary-surface-structure pitch and/or the secondary-surface-structure pitch. At least in regions, a secondary pitch being associated with the secondary image when seen along the extension direction of the surface structure preferably matches or mismatches the primary-surface-structure pitch and/or the secondary-surface-structure pitch.
As mentioned earlier, the distance between successive primary surface structure elements when seen along the extension direction of the surface structure is referred to as primary-surface-structure pitch and the distance between successive secondary surface structure elements when seen along the extension direction is referred to as secondary-surface-structure pitch.
Said primary-surface structure pitch and/or secondary-surface-structure pitch is preferably, at least in regions, aligned or misaligned with the primary pitch of the primary image and/or with the secondary pitch of the secondary image.
To this end it is therefore preferred that a primary pattern is present in the primary image, and wherein said primary pattern defines the primary pitch. Likewise, it is preferred that a secondary pattern is present in the secondary image, and wherein said secondary pattern defines the secondary pitch. For instance, the primary image can comprise a primary pattern that has, for instance, the form of a screen such as a round screen, line screen, elliptical screen or the like. In this case the primary pitch can be seen as the distance between successive screen lines with respect to the extension direction of the surface structure. Likewise, the secondary image can comprise a secondary pattern that has, for instance, the form of a screen such as a round screen, line screen, elliptical screen or the like, wherein the secondary pitch can be seen as the distance between successive screen lines with respect to the extension direction of the surface structure.
Moreover, it is preferred that the secondary pattern of the secondary image corresponds to the primary pattern of the primary image, but at least in regions being shifted with respect to the extension direction, for instance by a half-period of the modulation pattern and/or a half pitch of the primary surface structure elements and/or of the secondary surface structure elements. Hence, in a sense, the primary pattern can be seen as a modulation pattern, and wherein the secondary pattern corresponds to said modulation pattern that is however shifted. Again in other words, the primary image can be seen as being modulated according to at least one modulation pattern, and wherein the secondary image is preferably modulated according to the at least one modulation pattern but shifted, for instance by a half-period of the modulation pattern and/or a half pitch of the primary surface structure elements and/or of the secondary surface structure elements. That is, the modulation pattern is particularly preferably associated with the primary-surface-structure pitch and/or the secondary-surface-structure pitch. In other words, the primary image, in the region of the secondary image, is preferably distorted, reformed or modified according to the secondary image. For instance, the primary image can be formed by dark and bright lines, and wherein said dark lines and bright lines are alternatingly arranged along the surface structure and the extension direction. The secondary image can be formed by shifting the order of the dark and bright lines along the extension direction, whereby the secondary image is encoded into the primary image. In a sense, the shifted dark and bright lines of the secondary image can be seen as deviations in the dark and bright lines of the primary image with respect to the extension direction. In this way the secondary image is made unobservable, i.e. hidden or encoded, with respect to the primary image unless the data carrier is observed under particular viewing angle(s) and/or illuminated under particular illumination angle(s).
By aligning and/or misaligning the pitches of the primary image and/or of the secondary image with the pitches of the primary surface structure elements and/or the secondary surface structure elements, different appearances of the image can be generated.
For instance, if there is a mismatch between i) the primary-surface-structure pitch and/or the secondary-surface structure pitch and ii) the primary pitch of the primary image and/or the secondary pitch of the secondary image, optical effects of the security element such as a Moiré-effect can be generated. In the event of matching pitches, other optical effects such as flip effects can be generated, etc. Hence, the security element can be configured to exhibit different appearances based on optical effects when being observed under different viewing angles and/or when being illuminated under different illumination angles.
For example, at least part of the primary image can comprise primary colour pixels and the secondary image can comprise secondary colour pixels, wherein the primary image is modulated according to at least one modulation pattern and the secondary image is modulated according to the at least one modulation pattern but shifted preferably by a half-period of the modulation pattern, whereby a difference in appearance between the primary colour pixels and the secondary colour pixels is created when the data carrier is viewed under different viewing angles while an average appearance of the security element remains unchanged.
In any case, the data carrier can further comprise at least one marking material being configured to interact with impinging laser radiation, and wherein the surface structure preferably corresponds to a laser marking being generated in the marking material. Additionally or alternatively, the surface structure can correspond to an embossing. Additionally or alternatively, the carrier body and/or the surface structure can comprise or consist of one or more paper-based compounds and/or one or more cardboard-based compounds and/or one or more plastics and/or one or more polymers. Additionally or alternatively, the surface structure can correspond to a print, preferably an inkjet print.
The above explanations refer to the surface structure. It should be noted that explanations regarding the generation of the surface structure apply to the generation of the primary surface structure and the secondary surface structure unless stated otherwise.
that is, the data carrier can further comprise at least one marking material being configured to interact with impinging laser radiation, and wherein the surface structure corresponds to a laser marking being generated in the marking material. That is, the surface structure can be generated by irradiating laser radiation onto the data carrier, in particular onto the marking material. However, it is likewise conceivable that the surface structure corresponds to an embossing. It is furthermore conceivable that the surface structure corresponds to a print, preferably an inkjet print.
The carrier body and/or the surface structure can comprise or consists of one or more paper-based compounds and/or one or more cardboard-based compounds and/or one or more plastics and/or one or more polymers.
The polymers preferably are thermoplastics and/or amorphous polymers, particularly preferably polycarbonate and/or polycarbonate blends and/or polycarbonate co-extrudates.
The carrier body preferably comprises one or more layers of at least one of a paper-based compound, a cardboard-based compound, a plastics or a polymer. Two or more layers are preferably connected to one another by means commonly known in the state of the art. For instance, if the carrier body comprises two or more layers comprising or consisting of polymers and/or plastics, these layers could be connected to one another via lamination. In this case, the carrier body preferably corresponds to a so-called card body as it is commonly known in the card industry. However, other types of layers and/or connection means are likewise conceivable. For instance, layers of a paper-based compound could be glued to one another.
In the event that the data carrier comprises the marking material, it is preferred to provide the marking material after the carrier body is generated on a surface of the carrier body, in particular on a top surface of the carrier body. To this end it is preferred that the marking material is provided as one or more layers as well. The marking material particularly preferably corresponds to polycarbonate or another plastic that preferably comprises laser sensitive additives. Once that the marking material is provided on the carrier body, it is preferred to generate the surface structure in the marking material by irradiating laser radiation onto the marking material. In regions of impingement of the laser radiation, the marking material is preferably colour-changed around the laser sensitive additives, and wherein a strong reaction can result in a foam like structure that extends up from a surface of the data carrier. Such marking is typically black and is generally known as tactile laser marking. With some lasers and/or laser settings it is possible to achieve also whitish tactile marking.
However, it is likewise conceivable that no such marking material is present. In this case, it is preferred that the surface structure is produced in the carrier body itself, preferably by embossing a structure into the carrier body, particularly preferably into the top surface of the carrier body. For instance, said structure could be provided on a lamination plate that is used to laminate the layers of the card body, wherein the structure is embossed into the carrier body and the surface structure in the form of an embossing is generated. As such, it is preferred that the surface structure is an integral component, i.e. formed into, the top surface of the carrier body.
In the event of the surface structure being a print such as an inkjet print said print is preferably printed on a surface of the carrier body as just mentioned.
The surface structure being a print preferably corresponds to a three-dimensional profile being printed. Said surface structure particularly preferably is inkjet printed according to known inkjet techniques. That is, the surface structure can be generated in different ways such as by intaglio printing or lamination, tactile laser marking or printing.
In the event of a plastic product it is preferred that a plastic surface is embossed for instance by heat and that pressure using a structured lamination plate surface against the substrate surface is applied. In the event of a paper product, it is preferred to use a specific printing process that similarly uses structured plates and high pressure (not heat), which is also known as Intaglio printing. However, it is likewise conceivable to use plates only and no ink, wherein an embossing in the paper surface being similar to the lamination of the plastic surface is achieved.
The data carrier preferably defines a top side, and wherein the security element is provided on the top side the data carrier.
The security element is particularly preferably provided on a top surface, i.e. the outermost surface, of the data carrier. As such, it is preferred that the security element is arranged on the data carrier so as to face towards an outside of the data carrier.
Said top surface of the data carrier preferably corresponds to the top surface of the carrier body or to the marking material. Consequently, in the former case, it is preferred that the surface structure is an integral component of the top surface of the data carrier. In the latter case, it is preferred that the marking component and thus the surface structure is arranged on the top surface of the data carrier.
In another aspect a secure article comprising or consisting of at least one data carrier as described above is provided. The secure article preferably is an identity card, a passport, a credit card, a smart card, a driving licence, a data page or the like.
It should be understood that the data carrier per se can correspond to a secure article. This is the case if the data carrier is provided in the form of an identity card, for example. However, it is likewise conceivable to introduce or incorporate the data carrier into a secure article. In the case of a passport for example the data carrier could correspond to or could be incorporated in a page of the passport.
Any explanations provided with regard to the data carrier per se preferably likewise apply to the secure article and vice versa.
In another aspect, a method of producing a data carrier for a secure article such as a passport is provided. The data carrier preferably is the data carrier as described above. The method comprises the steps of i) providing a carrier body, and ii) providing at least one security element on the carrier body. The security element comprises at least one image and at least one surface structure. The image comprises at least one primary image and at least one secondary image being encoded in the primary image. The surface structure comprises primary surface structure elements and secondary surface structure elements. The image is at least partially printed onto the primary surface structure elements. At least the secondary surface structure elements are configured to decode the secondary image when the data carrier is viewed under different viewing angles and/or illuminated under different illumination angles, whereby the secondary image becomes observable.
Any statements made with regard to the data carrier per se preferably likewise apply to the method of producing the data carrier and vice versa.
The security element is preferably provided by:

Providing an original image;
Selecting at least a first area of the original image to be assigned to the primary image and selecting at least a secondary area of the original image to be assigned to the secondary image, wherein the secondary area is preferably arranged inside the primary area;
Modulating the primary area according to at least one modulation pattern, whereby the primary image is formed;
Modulating the secondary area according to the at least one modulation pattern and shifting said modulated secondary area, whereby the secondary image is formed;
Recombining the primary image and the secondary image, whereby the image is formed; and
Printing said image onto the surface structure preferably with an inkjet printer.

The modulation pattern preferably corresponds to a screen such as a round screen, line screen or elliptical screen.
The primary area and the secondary area are preferably modulated by changing at least one of a luminance, intensity, brightness or colour of the primary area and the secondary area, preferably of colour pixels to be assigned to primary colour pixels of the primary image and of colour pixels to be assigned to secondary colour pixels of the secondary image.
The modulated secondary area is preferably shifted along at least one spatial direction and/or along the extension direction of the surface structure.
The modulated secondary area is preferably shifted in accordance with the primary-surface-structure pitch of the primary surface structure elements and/or the secondary-surface-structure pitch of the secondary surface structure elements, the modulated secondary area preferably being shifted by half of the primary-surface-structure pitch and/or by half of the secondary-surface-structure pitch.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,

Fig. 1: shows a sectional view of surface structure element of a surface structure according to the invention being compared with a surface structure element of a surface structure of the prior art;
Fig. 2: shows a sectional view of surface structure according to the invention;
Fig. 3: shows a sectional view of another surface structure according to the invention;
Fig. 4: shows a sectional view of another surface structure according to the invention;
Fig. 5: shows a perspective view of a surface structure comprising an image according to the invention;
Fig. 6: shows another perspective view of the surface structure comprising the image according to figure 5;
Fig. 7: shows a top view of the surface structure comprising the image according to figure 5;
Fig. 8: shows a sectional view of another surface structure according to the invention;
Fig. 9: shows a perspective view of another surface structure comprising an image according to the invention;
Fig. 10: shows another perspective view of the surface structure comprising the image according to figure 9;
Fig. 11: shows a top view of the surface structure comprising the image according to figure 9;
Fig. 12: shows a sectional view of another surface structure according to the invention;
Fig. 13: shows a perspective view of another surface structure comprising an image according to the invention;
Fig. 14: shows another perspective view of the surface structure comprising the image according to figure 13;
Fig. 15: shows a top view of the surface structure comprising the image according to figure 13, wherein the letters A to C are annotations describing different parts of the surface structure and the image;
Fig. 16a-16c: show partial views of a data carrier comprising a security element that comprises an image in the form of a primary image and an encoded secondary image on a surface structure, wherein the data carrier is viewed under different viewing angles and illuminated under different illumination angles, whereby the secondary image being becomes observable;
Fig. 17: shows an enlarged partial view of a security element according to figures 16a to 16c being provided as a digitally processed image;
Fig. 18: shows an enlarged partial view of the security element according to figures 16a to 16c being provided on a substrate.

DESCRIPTION OF PREFERRED EMBODIMENTS

Various aspects of a data carrier 1 for a secure article according to the invention will now be discussed in greater detail with respect to the figures.
That is and as follows from figures 5 to 18, the present invention concerns a data carrier 1 for a secure article that comprises a carrier body 2, and at least one security element 3 being provided on the carrier body 2. The security element 3 comprises at least one image 4 and at least one surface structure 5. The image 4 comprises at least one primary image 6 and at least one secondary image 7 being encoded in the primary image 6. The surface structure 5 comprises at least primary surface structure elements 8 and secondary surface structure elements 9. The image 4 is at least partially printed onto the primary surface structure elements 8. At least the secondary surface structure elements 9 are configured to decode the secondary image 7 when the data carrier 1 is viewed under different viewing angles α and/or illuminated under different illumination angles β, whereby the secondary image 7 becomes observable.
Hence, the surface structure 5 according to the invention comprises at least primary and secondary surface structure elements 8, 9.
For illustrative purposes, figure 1 depicts a comparison between a surface structure 5 according to the invention, which comprises in the depicted case a secondary surface structure element 9 protruding from a primary surface structure element 6, with a surface structure 100 of the prior art that can be said to comprise a primary surface structure element 1001 only. As can be deduced from figure 1, the lower a height of the surface structure is, the smaller viewing angle is required for a decoding of the secondary image. In other words, a user needs to tilt the data carrier more to unravel the encoded data. A such, a larger height of the surface structure is therefore beneficial for the effect. However, when the height of the surface structure is increased, a printing surface provided by the surface structure becomes very steep, which is not optimal for the printing process as the ink could flow to a bottom of surface structure resulting in a poor image quality. A better approach is thus to keep a printing surface of the surface structure relatively flat while enhancing an encoding/decoding effect of the surface structure. The surface structure according to the invention and depicted in figure 1 achieves this by comprising a primary surface structure element that will receive the print at a reasonably low height and an added secondary surface structure element that is here in the form of a thin embossed line on top of the primary surface structure element. In the depicted example, the secondary surface structure element by means of the embossing line changes an illumination angle β and/or a viewing angle α required to decode the secondary image from 22,6° to 36,7°.
Figures 2 to 4 depicts different surface structures 5 according to the invention, wherein the surface structure 5 extends from a top surface 10 of the carrier body 2 (figure 2), wherein the surface structure 5 is entirely arranged offset inwards with respect to a top surface 10 of the carrier body 2 in the direction of an interior of the carrier body 2 (figure 3), and wherein the surface structure 5 is partially arranged offset inwards with respect to a top surface 10 of the carrier body 2 in the direction of an interior of the carrier body 2 (figure 4), respectively.
Figures 5 to 7 depict the surface structure 5 according to figure 2, i.e. protruding from the top surface 10 of the carrier body 2, and wherein an image 4 comprising a primary image 6 (indicated in white) and an encoded secondary image 7 (indicated in grey) has been printed on the surface structure 5.
All of these surface structures 5 have in common that the secondary surface structure elements 9 protrude from the primary surface structure elements 8 at a location of maximal height hp of the primary surface structure elements 8. When seen along an extension direction E of the surface structure 5, the primary surface structure elements 8 are arranged at a distance from one another and the secondary surface structure elements 9 are arranged at a distance from one another. In these figures, the primary surface structure elements 8 when seen along an extension direction E of the surface structure 5 are associated with a primary-surface-structure pitch and the secondary surface structure elements 9 when seen along the extension direction of the surface structure 5 are associated with a secondary-surface-structure pitch. Furthermore, a primary pitch being associated with the primary image 6 when seen along the extension direction E of the surface structure 5 matches the primary-surface-structure pitch and the secondary-surface-structure pitch.
The distance between successive primary surface structure elements 8 when seen along the extension direction E of the surface structure 5 is referred to as primary-surface-structure pitch and the distance between successive secondary surface structure elements 9 when seen along the extension direction E is referred to as secondary-surface-structure pitch. The primary pitch corresponds to the distance between successive screen lines associated with the primary image 6 and with respect to the extension direction E of the surface structure 5 and the secondary pitch corresponds to the distance between successive screen lines associated with the secondary image 7 and with respect to the extension direction E of the surface structure 5.
As follows from figures 5 to 7, depending on a viewing angle α under which the data carrier 1 is viewed, one side of the surface structure 5 becomes more visible resulting in a dominating appearance of the primary image 6 (figure 5) or the secondary image 7 (figure 6).
Furthermore, in these examples an angle of inclination γ between a reference plane pc of the carrier body 2 and a reference plane pp of the primary surface structure elements 8 is about 25°, and an angle of inclination δ between a reference plane pc of the carrier body 2 and a reference plane ps of the secondary surface structure elements 9 is about 80°, see corresponding indications in figures 1 and 2.
Figures 8 to 11 depict another surface structure 5 according to the invention, wherein said surface structure 5 essentially differs from the surface structures 5 of figures 2 to 7 in that a plurality of secondary surface structure elements 9 are arranged per primary surface structure element 8, and wherein said plurality of secondary surface structure elements 9 protrude from the primary surface structure elements 8 among various locations of the primary surface structure elements 8, i.e. not only at a location of maximal height.
Figures 12 to 15 depict another surface structure 5 according to the invention that again differs from the surface structures 5 depicted in figures 2 to 11. In fact, a major difference lies in the angle of inclination γ between a reference plane pc of the carrier body 2 and a reference plane pp of the primary surface structure elements 8 that is about 0°. That is, the primary surface structure 8 elements are essentially flat. An angle of inclination δ between a reference plane pc of the carrier body 2 and a reference plane ps of the secondary surface structure elements 9 however is again about 80°. Furthermore, when seen along the extension direction E of the surface structure 5, successive primary surface structure elements 8 are separated from one another via a secondary surface structure element 9. In other words, when seen along the extension direction of the surface structure 5, primary surface structure elements 8 and secondary surface structure elements 9 are arranged in an alternating manner.
For illustrative purposes, annotations describing different areas of the surface structure 5 and the image 4 are indicated in figure 15. Th letter "A" denotes the secondary surface structure elements 9, i.e. the tall embossed lines. The letter "B" denotes the primary image 6 such as an inkjet print being printed on the primary surface structure elements 8. The letter "C" denotes the secondary image 7 such as an inkjet print being printed on the primary surface structure elements 8. Hence, also in this case a decoding of the secondary image 7 is achieved upon viewing or illuminating the data carrier 1 under different viewing angles or illumination angles, respectively.
All surface structures 5 of figures 2 to 15 have in common that a maximal height hs of the secondary surface structure elements 9 with respect to a reference plane pc running parallel to a surface plane 11 of the carrier body 2 is larger than a maximal height hp of the primary surface structure elements 8 with respect to said reference plane of the carrier body 2.
Figures 16a to 16c show partial views of a security element 3 comprising an image 4 being printed on a surface structure 5 as described in figures 5 to 7, wherein the image 4 comprises a primary image 6 in the form of a portrait that has been modulated according to a modulation pattern in the form of alternating light and dark grey lines and wherein part of this modulation has been shifted so as to generate an encoded secondary image 7. In fact, and as best visible in figures 17 and 18, the shifting corresponds to the order of the alternating lines being changed locally at positions inside the primary image 6 in the form of the portrait so as to form the secondary image 7 in the form of alphanumerical text. Depending on a viewing angle or an illumination angle the observer sees the primary image or portrait 6 without the secondary image or alphanumerical text 7, i.e. the alphanumeric text or secondary image 7 being encoded in the primary image 6 or being revealed.
In particular, figure 16a depicts the security element 3 upon an illumination with side light, wherein the image 4 appears with a strong light/shadow effect. In this case, the secondary surface structure elements 9, being higher than the primary surface structure elements 8, dominate the shadow creation, whereas the primary surface structure elements 8 may participate to the effect. Figure 16b depicts the security element 3 upon tilting the data carrier 1, i.e. under a different viewing angle, wherein the secondary surface structure elements 8, again being higher than the primary surface structure elements 8, dominate in hiding/revealing the print 4. Figure 16 c again depicts the security element 3 upon tilting the data carrier 1, wherein the data carrier 1 is viewed under an acute viewing angle.

LIST OF REFERENCE SIGNS

1: data carrier
2: carrier body
3: security element
4: image
5: surface structure
6: primary image
7: secondary image
8: primary surface structure element
9: secondary surface structure element
10: top surface of carrier body
11: surface plane of carrier body

100: surface structure of prior art
101: surface structure element of prior art

α: viewing angle
β: illumination angle
γ: inclination angle
δ: inclination angle
hs: maximal height of secondary surface structure element
hp: maximal height of primary surface structure element
pc: reference plane of carrier body
pp: reference plane of primary surface structure element
ps: reference plane of secondary surface structure element
E: extension direction of surface structure

Claims

A data carrier (1) for a secure article such as a passport comprising:
- a carrier body (2), and

- at least one security element (3) being provided on the carrier body (2);
wherein the security element (3) comprises at least one image (4) and at least one surface structure (5),

wherein the image (4) comprises at least one primary image (6) and at least one secondary image (7) being encoded in the primary image (6),

characterized in that the surface structure (5) comprises at least primary surface structure elements (8) and secondary surface structure elements (9),

wherein the image (4) is at least partially printed onto the primary surface structure elements (8), and

wherein at least the secondary surface structure elements (9) are configured to decode the secondary image (7) when the data carrier (1) is viewed under different viewing angles (α) and/or illuminated under different illumination angles (β), whereby the secondary image (7) becomes observable.
The data carrier (1) according to claim 1, wherein the primary surface structure elements (8) are configured to reflect light such, that the secondary image (7) is decoded when the data carrier (1) is viewed under different viewing angles α and illuminated under different illumination angles (β), and/or
wherein the primary surface structure elements (8) are configured to at least partially block impinging light such, that the primary surface structure elements (8) participate in the decoding of the secondary image (7) when the data carrier (1) is illuminated under different illumination angles (β), preferably under one or more illumination angles (β) being smaller than 25°.
The data carrier (1) according to any one of the preceding claims, wherein the secondary surface structure elements (9) are configured to decode the secondary image (7) when the data carrier (1) is viewed under viewing angles (α) being 20° or more, preferably 35° or more such as about 45°.
The data carrier (1) according to any one of the preceding claims, wherein the image (4), in particular the primary image (6) and the secondary image (7), is essentially entirely printed onto the primary surface structure elements (8), and/or
wherein the secondary surface structure elements (9) are essentially free from the print.
The data carrier (1) according to any one of the preceding claims, wherein the surface structure (5) extends from a top surface (10) of the carrier body (2), or
wherein the surface structure (5) is at least partially arranged offset inwards with respect to a top surface (10) of the carrier body (2) in the direction of an interior of the carrier body (2).
The data carrier (1) according to any one of the preceding claims, wherein a maximal height (hs) of the secondary surface structure elements (9) with respect to a reference plane (pc) running parallel to a surface plane (11) of the carrier body (2) is larger than a maximal height (hp) of the primary surface structure elements (8) with respect to said reference plane of the carrier body (2), and/or
wherein the secondary surface structure elements (9) are configured to protect the primary surface structure elements (8) and/or the image (4) from wear.
The data carrier (1) according to any one of the preceding claims, wherein an angle of inclination between a reference plane (pc) of the carrier body (2) and a reference plane (pp) of the primary surface structure elements (8) is 45° or less, the angle of inclination preferably being about 25° or preferably being 10° or less such as about 0°, and/or
wherein an angle of inclination between a reference plane pc of the carrier body (2) and a reference plane (ps) of the secondary surface structure elements (9) is 45° or more, preferably 80° or more such as about 90°.
The data carrier (1) according to any one of the preceding claims, wherein the secondary surface structure elements (9) protrude from the primary surface structure elements (8), preferably at a location of maximal height of the primary surface structure elements (8).
The data carrier (1) according to any one of the preceding claims, wherein two or more secondary surface structure elements (9) are arranged per primary surface structure element (8), and
wherein the secondary surface structure elements (9) preferably protrude from the primary surface structure elements (8).
The data carrier (1) according to any one of claims 1 to 7, wherein, when seen along the extension direction (E) of the surface structure (5), successive primary surface structure elements (8) are separated from one another via a secondary surface structure element (9), and/or
wherein, when seen along the extension direction of the surface structure (5), primary surface structure elements (8) and secondary surface structure elements (9) are arranged in an alternating manner.
The data carrier (1) according to any one of the preceding claims, wherein, when seen along an extension direction (E) of the surface structure (5), the primary surface structure elements (8) are arranged at a distance from one another and/or the secondary surface structure elements (9) are arranged at a distance from one another.
The data carrier (1) according to any one of the preceding claims, wherein the primary surface structure elements (8) when seen along an extension direction (E) of the surface structure (5) are associated with a primary-surface-structure pitch and the secondary surface structure elements (9) when seen along the extension direction of the surface structure (5) are associated with a secondary-surface-structure pitch, and
wherein, at least in regions, a primary pitch being associated with the primary image (6) when seen along the extension direction (E) of the surface structure (5) matches or mismatches the primary-surface-structure pitch and/or the secondary-surface-structure pitch, and/or
wherein, at least in regions, a secondary pitch being associated with the secondary image (7) when seen along the extension direction (E) of the surface structure (5) matches or mismatches the primary-surface-structure pitch and/or the secondary-surface-structure pitch.
The data carrier (1) according to any one of the preceding claims, wherein at least one of:
- the data carrier (1) further comprises at least one marking material being configured to interact with impinging laser radiation, and wherein the surface structure (5) corresponds to a laser marking being generated in the marking material,

- the surface structure (5) corresponds to an embossing,

- the carrier body (2) and/or the surface structure (5) comprises or consists of one or more paper-based compounds and/or one or more cardboard-based compounds and/or one or more plastics and/or one or more polymers, or

- the surface structure (5) corresponds to a print, preferably an inkjet print.
A secure article comprising or consisting of at least one data carrier (1) as claimed in any one of the preceding claims, the secure article preferably being an identity card, a passport, a credit card, a smart card, a driving licence, a data page or the like.
A method of producing a data carrier (1) for a secure article such as a passport, the data carrier (1) preferably being the data carrier (1) as claimed in any one of claims 1 to 13, wherein the method comprises the steps of:
- Providing a carrier body (2), and

- Providing at least one security element (3) on the carrier body (2);
wherein the security element (3) comprises at least one image (4) and at least one surface structure (5),

wherein the image (4) comprises at least one primary image (6) and at least one secondary image (7) being encoded in the primary image (6),

characterized in that the surface structure (5) comprises primary surface structure elements (8) and secondary surface structure elements (9),

wherein the image (4) is at least partially printed onto the primary surface structure elements (8), and

wherein at least the secondary surface structure elements (9) are configured to decode the secondary image (7) when the data carrier (1) is viewed under different viewing angles (α) and/or illuminated under different illumination angles (β), whereby the secondary image (7) becomes observable.