A data carrier, a secure article and a method of producing a data carrier

Abstract

A data carrier (1) for a secure article (1000) comprises a carrier body (2) and at least one security element (3). The security element (3) comprises at least one primary security element (4) and at least one secondary security element (5) being encoded in the primary security element (4). The secondary security element (5) is configured to be decoded via at least one decoding device (6) and is configured such that, when being decoded with the decoding device (6), an appearance of the secondary security element (5) changes depending on a viewing angle under which the data carrier (1) is viewed. The primary security element (4) is modulated according to at least one modulation pattern, and wherein at a location of the secondary security element (5) the modulation pattern comprises at least one modification, whereby the secondary security element (5) is encoded in the primary security element (4). The modulation pattern is associated with a modulation pitch (MP) and a modulation orientation (MO). The modulation pitch (MP) mismatches a decoding pitch (DP) associated with the decoding device (6) and / or the modulation orientation (MO) mismatches a decoding orientation (DO) of the decoding device (6).

Description

TECHNICAL FIELD

[0001] 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

[0002] 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.SUMMARY OF THE INVENTION

[0003] It is an object of the present invention to provide a data carrier having an increased security against forgery.

[0004] This object is achieved with a data carrier according to claim 1.

[0005] That is, a data carrier for a secure article 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 primary security element and at least one secondary security element being encoded in the primary security element. The secondary security element is configured to be decoded via at least one decoding device. The secondary security element is configured such that, when being decoded with the decoding device, an appearance of the secondary security element changes depending on a viewing angle under which the data carrier is viewed. The primary security element is modulated according to at least one modulation pattern, and wherein at a location of the secondary security element the modulation pattern comprises at least one modification, whereby the secondary security element is encoded in the primary security element. The modulation pattern is associated with a modulation pitch and a modulation orientation. The modulation pitch mismatches a decoding pitch associated with the decoding device and / or the modulation orientation mismatches a decoding orientation of the decoding device.

[0006] The modulation pattern preferably corresponds to a two-dimensional function being associated with at least one of: a type of function, an amplitude of the function, a pitch of the function, or a phase of the function.

[0007] Various types of functions are conceivable, for instance a sinusoidal function or a non-sinusoidal function such as a sawtooth function.

[0008] The pitch of the function can be seen as the period of the function.

[0009] The function preferably is a periodic function.

[0010] Hence, the secondary security element is preferably encoded into the primary security element by a modification in the modulation pattern, i.e. by perturbing the primary security element by said two-dimensional function.

[0011] The modulation pitch of the modulation pattern is preferably defined by the pitch or the period of the two-dimensional function that modulates the primary security element.

[0012] The modulation orientation of the modulation pattern is preferably defined by the orientation of the modulation pattern on the carrier body.

[0013] The decoding pitch and the decoding orientation of the decoding device can be provided in many ways. For example, and as will be explained in greater detail below, the decoding device can be a lenticular decoding device comprising an array of lenses. In this case, an extension direction of the array defines the decoding orientation of the decoding device. Moreover, a distance between successive lenses in the array defines the decoding pitch of the decoding device.

[0014] Another conceivable decoding device is grid-like decoding device comprising a plurality of for instance opaque lines on an otherwise transparent or translucent area. In this case, an extension direction of the lines defines the decoding orientation and a line frequency of a number of lines per inch or a distance between two consecutive lines defines the decoding pitch.

[0015] Matching pitches preferably means that the pitches concerned equal one another or are integer multiples of one another. For instance, in the event of the modulation pattern and the decoding device comprising lines, a line frequency or a distance between two successive lines of the modulation pattern and of the decoding device equals one another or is an integer multiple of one another.

[0016] Mismatching pitches preferably means that the pitches concerned differ from one another and are non-integer multiplies from one another. For instance, the decoding pitch of the decoding device could be shifted by half of the modulation pitch. For instance, a line frequency or a distance between two successive lines of the decoding could differ from the modulation pitch or is a non-integer multiple thereof.

[0017] Hence, the present invention is based on the insight that mismatching pitches and / or mismatching orientations between the security element and the decoding device result in a so-called dynamic Moiré-effect.

[0018] Said dynamic Moire effect exhibits a Moire band moving across the security element upon viewing angle change. The Moire band makes a change of appearances such as a bright / dark reversal taking place in a varying location in dependence of the viewing angle, and this location moves as a band across the security element. Depending on the amount of mismatch one can influence the width of the Moire band and its angle.

[0019] In particular, the modulation and decoding orientations and pitches are well defined as generic quantities only for periodic modulation and decoding device (pitch is constant) and for rectilinear configurations of each (orientation is constant). However, it is naturally possible to conceive non-periodic modulation and non-linear shapes of the modulating function and decoding device (e.g. non-periodic and / or curved lenticular structures). The same principle of small mismatch of the orientation and / or pitch leading to the Moire effect holds true. To realize this the present invention considers the orientation and pitch as local variables, function of x and y dimensions in two dimensions. This leads to the possible implementation where the global geometry of the modulating function and that of the decoding device are very similar, and an accurate overlapping of the decoding device on top of the encoded secondary security element enables decoding of the encoded secondary security element and leads to the Moire effect depending on the local differences of the modulation and decoding geometries.

[0020] In any case, the secondary security element being encoded in the primary security element preferably means that it is hidden or non-observable in the absence of a decoding with the decoding device. In other words, without the decoding device, only the primary security element is observable.

[0021] In the event of two or more different encodings of the secondary security element in different spatial areas of the carrier body, see further below, these can be defined separately and differently for the different spatial areas, such as different angles, different Moire bandwidths, etc. In particular, depending on a relative angle between the decoding orientation of the decoding device and the modulation orientation of the modulation pattern as well as on an amount of mismatch between the decoding pitch and the modulation pitch, a movement direction of the Moire band can be selected. Furthermore, a movement speed of the Moire band can be selected depending on the modulation pitch and the amount of mismatch between the decoding pitch and the modulation pitch. The larger said amount of mismatch between the pitches is, the slower the Moire bands are moving.

[0022] To this end it is conceivable that the security element is associated with a modulation pattern comprising a single modulation pitch and a single modulation orientation. Likewise, it is conceivable that the decoding device is associated with a single decoding pitch and a single decoding orientation. However, and as will be outlined further below, it is likewise conceivable that the security element is associated with two or more modulation patterns comprising two or more different modulation pitches and / or two or more different modulation orientations. Likewise, the decoding device can be associated with two or more different decoding pitches and / or two or more different decoding orientations.

[0023] An extension direction and / or an orientation of the secondary security element on the carrier body equals or differs from the modulation orientation of the modulation pattern. Additionally or alternatively, a spatial expansion of the secondary security element along a width direction extending perpendicularly to the extension direction of the secondary security element equals or differs from the decoding pitch of the decoding device and / or the modulation pitch.

[0024] That is, any extension and / or orientation between the secondary security element such as a text direction and the modulation orientation of the modulation pattern is conceivable.

[0025] Moreover, a spatial expansion of the secondary security element along a width direction of the secondary security element such as a height of an image or a font size of a text and the decoding pitch of the decoding device as well as the modulation pitch of the modulation pattern are conceivable. To this end it is preferred that a font size correlates with the Moire bandwidth, for instance with half-bandwidth. And also the Moire bandwidth preferably depends on the size of the security element where it is being implemented such that one or at most a few Moire bandwidths are preferably generated across the security element.

[0026] The change of the appearance of the secondary security element upon changing the viewing angle under which the data carrier is viewed is preferably at least one of: a change in luminescence, a change in colour, a change in intensity, a change in brightness, or a change in reflectance.

[0027] That is, the secondary security element is preferably configured to exhibit a change in contrast upon changing the viewing angle under which the data carrier is viewed.

[0028] For instance, depending on a viewing angle under which the data carrier is viewed, the appearance of the secondary security element could change from bright to dark and vice versa.

[0029] The primary security element is associated with pixel values, and wherein said pixel values in the region of the secondary security element are modulated according to the modulation pattern such, that a difference in appearance of the pixel values of the primary security element and of the secondary security element is created when the data carrier is viewed under different viewing angles while an average appearance of the security element remains unchanged.

[0030] That is, the security element can comprise or consist of a modulated primary security element, wherein the modulation encodes the secondary security element into the primary security element by altering its pixel values.

[0031] To this end the secondary security element can be encoded in luminance and / or in colour space. That is, the secondary security element can be encoded by modulating pixel values associated with the primary security element up and down. For instance, the secondary security element can be encoded in luminance by changing adjacent pixel values into slightly darker and slightly brighter pixel values such, that an average appearance of these pixel values is original, i.e. unmodulated. Additionally or alternatively, the secondary security element can be encoded in colour space by using opposite colours of adjacent pixels such that the changes in the pixel values average to zero. For instance, the secondary security element can be encoded in colour space by changing adjacent pixel values into slightly more magenta pixel values and slightly more greenish pixel values such, that an average appearance of these pixel values is original, i.e. unmodulated.

[0032] The secondary security element preferably comprises at least a first secondary-security-element-part and a second secondary-security-element-part that are not fully rotationally symmetric and that have a different orientation on the carrier body.

[0033] For instance, a first part of the secondary security element, i.e. the first secondary-security-element-part, can be an alphanumeric character such as the text "Specimen" that is oriented along a first spatial direction the carrier body and the second part of the secondary security element, i.e. the second secondary-security-element-part, can be the same alphanumeric character "Specimen" that is oriented along a second spatial direction being at an angle to the first spatial direction. Other orientations are of course likewise conceivable such as curves discontinues lines and / or non-parallel lines, etc.

[0034] The secondary security element is preferably encoded according to a first encoding in a first spatial area of the carrier body being generated by the modulation pattern associated with the modulation pitch and the modulation orientation. The secondary security element is preferably furthermore encoded according to at least one second encoding in a second spatial area of the carrier body by a second modulation pattern modulating the primary security element and being associated with a second modulation pitch and a second modulation orientation.

[0035] That is, and as mentioned earlier, the secondary security element can be encoded into the primary security element according to at least two different encodings on at least two different spatial areas of the carrier body.

[0036] The first encoding is associated or generated by the primary security element being modulated by the modulation pattern mentioned initially, wherein said modulation is present in a first spatial area of the carrier body. For a better distinction said modulation pattern can also be referred to as first modulation pattern being associated with a first modulation pitch and a first modulation orientation, etc. Now, in addition to this (first) modulation pattern, it is conceivable that the primary security element is modulated in at least one second location according to a second modulation pattern, whereby the secondary security element is furthermore encoded into the primary security element according to a second encoding.

[0037] The first encoding preferably differs from the second encoding such that, when being decoded with the decoding device, an appearance of the secondary security element in the first spatial area differs from an appearance of the secondary security element in the second spatial area. The appearances of the secondary security element in the first spatial area and the second spatial area preferably change depending on a viewing angle under which the data carrier is viewed.

[0038] The second encoding or the second modulation pattern preferably differs from the first modulation pattern or the first encoding, respectively. Hence, in a sense, the secondary security element can be seen as comprising at least a first spatial-element-part and a second spatial-element-part, wherein the first spatial-element-part is encoded into the primary security element according to the first encoding and the second spatial-element-part is encoded into the primary security element according to a different second encoding. In other words, it is particularly preferred that the first modulation pattern encoding the secondary security element in the first spatial area, i.e. encoding the first spatial-element-part, differs from the second modulation pattern encoding the secondary security element in the second spatial area, i.e. encoding the second spatial-element-part. Said difference is preferably one or more different parameters of their two-dimensional functions modulating the primary security element, see above. In other words, different encoding parameters or modulation parameters are preferably present in the different spatial areas on the carrier body. For instance, a type of the functions and / or an amplitude of the functions and / or a pitch of the functions and / or a phase of the functions could be different from one another. However, and as noted above, the first and second modulation patterns can likewise be the same. Hence, in the former case, the security element comprises two or more spatial areas exhibiting different Moiré-dynamics. In the latter case, the security element comprises two or more spatial areas exhibiting a single or common Moiré dynamics.

[0039] As a consequence, when being decoded, an appearance of the secondary security element in these different spatial areas differs from one another. For instance, the appearance in the first spatial area could be bright under a first viewing angle and change into a dark appearance under the second viewing angle, and the appearance in the second spatial area could be dark under the first viewing angle and change into a bright appearance under the second viewing angle. It should be noted that the secondary security element can be encoded according to two or more different encodings on two or more spatial areas. Explanations regarding two different encodings likewise apply to more than two different encodings and vice versa.

[0040] The decoding pitch and the decoding orientation of the decoding device is preferably associated with the first encoding of the secondary security element. The decoding device is preferably furthermore associated with a second decoding pitch and a second decoding orientation. The second modulation pitch preferably matches or mismatches the second decoding pitch. Additionally or alternatively, the second modulation orientation preferably matches or mismatches the second decoding orientation.

[0041] That is, in addition to the decoding pitch and decoding orientation of the decoding device mentioned so far, which again for better distinction can be referred to as first decoding pitch and first decoding orientation, it is conceivable that the decoding device is associated with at least one second decoding pitch and second decoding orientation. Whereas the first decoding orientation and decoding pitch is preferably associated with the first encoding of the security element, the second decoding pitch and decoding orientation is preferably associated with the second encoding of the secondary security element.

[0042] To this end it is conceivable that second modulation pitch matches or mismatches the second decoding pitch and / or that the second modulation orientation matches or mismatches the second decoding orientation.

[0043] However, it should be noted that the decoding device can be associated with a single or uniform decoding pitch and decoding orientation that is associated with both encodings, i.e. the first and the second encoding of the secondary security element.

[0044] The first spatial area and the second spatial area are preferably arranged adjacent to one another or spaced apart from one another on the carrier body. Additionally or alternatively, a spatial expansion of the first spatial area and a spatial expansion of the second spatial area are preferably the same or different from one another. Additionally or alternatively, a shape of the secondary security element in the first spatial area and a shape of the secondary security element in the second spatial area are preferably the same or different from one another.

[0045] That is, the secondary security element in the first and second spatial areas can be provided in the form of shapes, such as geometric shapes or random shapes.

[0046] These shapes can be arranged adjacent or spaced apart from one another on the carrier body.

[0047] Moreover, these shapes can have the same or a different spatial expansion, i.e. they can have a same size or a different size.

[0048] For instance, the before-mentioned first spatial-element-part of the secondary security element of bright appearance under the first viewing angle could be arranged immediately next to the second spatial-element-part of the secondary security element of dark appearance under the first viewing angle, and wherein the bright first spatial-element-part could have a circular shape and the dark second spatial-element-part could have a rectangular shape, and wherein said bright first spatial-element-part is smaller than the dark coloured second spatial-element-part. Of course, a variety of other shapes and sizes and appearances are likewise conceivable.

[0049] At least part of the secondary security element being encoded according to the first encoding preferably extends on the carrier body along a first extension direction and / or has a first orientation and at least part of the secondary security element being encoded according to the second encoding preferably extends on the carrier body along a second extension direction being different from the first extension direction and / or has a second orientation different from the first orientation.

[0050] In the event of the secondary security element comprising the at least two-secondary-security-element-parts mentioned earlier that are not fully rotationally symmetric and that have different orientations, these two parts may have a same appearance under the first viewing angle and a different but again same appearance under the second viewing angle. In other words, the different parts of the secondary security element could be encoded into the primary security element according to an invariant or a same encoding. However, it is just as conceivable that these two or more secondary-security-element-parts are also encoded in two or more spatial areas of the carrier body according to two or more different encodings. In other words, the secondary security element can be provided according to both aspects, i.e. it can comprise two or more parts being oriented differently on the carrier body and being not fully rotationally symmetric and that are also encoded according to two or more encodings in the primary security element. Statements regarding the secondary security element, which is encoded according to at least two encodings, thus preferably also apply to the secondary security element comprising two or more parts that have different orientations and are not fully rotationally symmetric and vice versa.

[0051] For the sake of completeness, it should be noted here that the data carrier can have one or more security elements which comprise a secondary security element encoded according to at least two encodings, as well as one or more security elements which comprise a secondary security element comprising at least two secondary-security-element-parts that are not fully rotationally symmetric and that have different orientations on the carrier body.

[0052] The security element preferably is a print and / or coloured. Additionally or alternatively, the primary security element is preferably observable to an un-aided eye. Additionally or alternatively, the secondary security element is preferably non-observable to an un-aided eye. Additionally or alternatively, the primary security element and / or the secondary security element preferably have the shape of a picture and / or an alphanumeric character. Additionally or alternatively, the primary security element and / or the secondary security element are preferably machine readable.

[0053] That is, the security element is preferably a print. To this end various printing techniques are conceivable such as intaglio, offset, silkscreen, or ink jet.

[0054] Additionally or alternatively, the security element can comprise or consist of an ink, for instance visible ink being visible to the unaided eye, fluorescent ink, infra-red transparent ink, or infra-red absorbent ink.

[0055] Additionally or alternatively, the security element is preferably colored and particularly preferably corresponds to a colored print.

[0056] The security element can be provided on a top side of the data carrier. That is, the data carrier preferably defines a top side, and wherein said top side is provided by a top surface of the carrier body on which the security element is provided, in particular printed.

[0057] The carrier body 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.

[0058] 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.

[0059] To this end it is particularly preferred that the security element to be printed is generated from an original security element such as an original image and / or an original alphanumeric character, wherein said original image and / or original alphanumeric character is modulated at the location of the secondary security element, wherein its pixel values are modulated i.e. changed as explained earlier. The modulation is preferably made so that an average appearance over one period is identical to the original image and / or the original alphanumeric character. The thus generated secondary security element is hidden or encoded into a phase shift of the preferably periodic modulation pattern. To this end said encoding or "hiding" is preferably based on the fact that said phase shift is a small discontinuity between adjacent pixels that is not recognizable by the bare eye, and wherein an average local appearance over a modulation period is preserved as compared to the original image and / or the original alphanumeric character.

[0060] Thus, in a sense, there is an original security element such as an original image and / or an original alphanumeric character to be provided such as printed on the data carrier and the actually printed security element such as the printed image and / or the printed alphanumeric character. The former is preferably modulated based on the binary map of the secondary security element. That is, the primary security element may be understood as a binary image and / or a binary alphanumeric character defining pixel by pixel the locations of the encoded secondary security element. Consequently, the secondary security element is preferably not colorful and the primary security element preferably defines a basic color space available. However, the primary security element could likewise be gray scale that contains colored encoding and vice versa.

[0061] The secondary security element is preferably at least regionally printed along a non-straight and / or arbitrary direction.

[0062] That is, the secondary security element is preferably not printed along straight lines, but along non-straight and / or arbitrary or even discontinues and / or non-parallel lines.

[0063] The primary security element can be printed along such non-straight and / or arbitrary directions as well. However, it is likewise preferred that the primary security element is printed along straight and / or parallel lines.

[0064] The decoding device is preferably configured to mask and / or magnify and / or suppress at least part of the security element such, that the secondary security element is decoded. Additionally or alternatively, the decoding device preferably is a physical decoding device, for instance a lenticular decoding device or a grid-like decoding device, or a digital decoding device.

[0065] The decoding device can be an integral part of the data carrier such as incorporated into a data page of a data carrier in the form of a passport or booklet. However, it is likewise conceivable that the decoding device is a separate component being used, for instance, by a security officer that inspects the data carrier. An example of such a separate decoding device is a lenticular decoding device or a grid-like decoding device. These decoding devices are physical devices. A decoding is preferably performed by superimposing the decoding device with the security element, for instance by arranging the data page comprising the decoding device above the security element, i.e. overlapping with the security element, which is in this case preferably provided or arranged in another data page. Likewise conceivable is such a decoding device being provided on one side of a transparent element or area of the data carrier and the security element being provided such as printed onto the opposite side of said transparent element or area.

[0066] That is, it is furthermore preferred that the data carrier comprises at least one transparent or translucent area such as a window, and wherein the decoding device is arranged or incorporated into said area or window. Likewise conceivable is a decoding device in the form of a sheet like material being attached to the data carrier, etc. Consequently, the decoding device preferably comprises at least one transparent and / or translucent area.

[0067] As has been mentioned earlier, a preferred physical decoding device is a lenticular decoding device. Said lenticular decoding device can be configured to selectively reveal and / or selectively mask certain parts of the security element, in particular of the primary security element, whereby the secondary security element is revealed, i.e. decoded. Additionally or alternatively, the lenticular decoding device can be configured to selectively magnify parts of the security element, whereby the secondary security element is revealed i.e. decoded. Other examples of conceivable physical decoding devices are a decoding grid that comprises, for instance, a plurality of non-transparent such as opaque grid lines provided on a transparent or translucent area. In any case, said masking or revealing or magnifying is preferably based on the viewing angle under which the data carrier is viewed.

[0068] These decoding devices can be implemented in various ways. For instance, the lenticular decoding device can comprise an array of lenses being formed such as embossed into at least one transparent and / or translucent area of the decoding device and / or the data carrier such as into a transparent polymer layer. Alternatively, the array of lenses can be provided on an external, i.e., separate decoding device of a security officer, see above. The lenses can have various shapes, i.e. not only lenticular but for instance also a cylindrical or spherical shape.

[0069] The grid-like decoding device can have a plurality of lines extending parallel to one another. However, other arrangements such as round or elliptical lines are likewise conceivable. These lines could be embossed or printed into at least one transparent and / or translucent area of the decoding device and / or the data carrier such as a transparent polymer layer. Alternatively, these lines could be applied to an external, i.e. separate decoding device of a security officer or the like, see above.

[0070] However, it is likewise conceivable that the decoding device is a digital decoding device and / or comprising or consisting of a non-transitory computer readable storage medium having computer readable instructions which, when implemented, cause a computer to simulate functions of a physical decoding device. That is, the decoding device can be configured for an electronic decoding process using at least one decoding function, i.e. a software simulation of one or more functions of a physical decoding device. In this case it is furthermore preferred that the decoding device comprises an electronic recognition being configured to recognize the security element and to simulate a decoding operation, and for instance displaying a dynamic animation of different viewing angles of the data carrier on a screen.

[0071] In particular, the at least one decoding function is preferably implemented as a line filter simulating the function of e.g. the lenticular decoding device. In linear and periodic configuration this would equal to considering only every Nth line in the captured security element in the decoding orientation, where N would correspond to the decoding pitch. The exact value of N preferably depends on the resolution of the captured security element, the modulation function, etc.

[0072] In the following, examples are given for conceivable decodings via hiding or suppressing or covering half of a modulation period of the modulation pattern associated with the security element. This likewise applies to the case of the security element being associated with two or more modulation patterns and the decoding device being associated with two or more decoding pitches and decoding orientations, respectively.

[0073] That is, the decoding device can be a rectilinear grid associated with a matching pitch and orientation that is covering or masking half of the security element, i.e. half-period.

[0074] As another example, the decoding device can be a rectilinear lens associated with a matching pitch and orientation that is deviating half of rays (from half-periods) out of the eye of an observer of the data carrier.

[0075] For example, the decoding pitch of a lens array can be such that several lines of the security element are arranged under each lens and when varying the viewing angle, the lens shows the different lines one after the other. That is, the lens elements can be arranged and configured such that different lines are made observable depending on the viewing angle. As another example, in the case of a digital decoding device, half of signals being associated with the security element can be suppressed for instance by multiplication with an estimated modulation pattern.

[0076] In these examples, a hiding, suppressing or covering half of the security element breaks the "averaging" between adjacent pixels. The whole security element becomes darker or brighter (depending on which half of security element is hidden), whereas the contrast of the encoded or hidden secondary security element increases and it is decoded or revealed or made observable, respectively.

[0077] As mentioned earlier, the decoding device can be configured uniformly or constant, i.e. comprising throughout the same decoding pitch and / or the same decoding orientation.

[0078] In the event of two or more different encodings of the secondary security element in the different spatial areas, such a uniform or constant decoding device nevertheless results in different optical effects because of the different encodings. That is, these different spatial areas can have different parametrizations of the encoding or modulation, see above. These different parameters could lead to different effects in the chosen color space, be it luminance, one color, or different in each spatial area.

[0079] However, it is also conceivable that the decoding device comprises different decoding pitches and / or different decoding orientations, each of which is preferably associated with the first encoding of the secondary security element in the first spatial area of the carrier body and the second encoding of the secondary security element in the second spatial area of the carrier body. Being associated preferably means that the decoding pitches are matching or mismatching the first and second modulation pitches of the primary security element and / or that the decoding orientations are the same or different from the first and second modulation orientations of the primary security element in a targeted or desired manner such that the security element exhibits a targeted or desired optical variability upon the decoding of the secondary security element.

[0080] 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.

[0081] Any explanations made with regard to the data carrier as such preferably likewise apply to the secure article comprising or consisting of the data carrier and vice versa.

[0082] 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 primary security element and at least one secondary security element being encoded in the primary security element. The secondary security element is configured to be decoded via at least one decoding device. The secondary security element is configured such that, when being decoded with the decoding device, an appearance of the secondary security element changes depending on a viewing angle under which the data carrier is viewed. The primary security is modulated according to at least one modulation pattern, and wherein at a location of the secondary security element the modulation pattern comprises at least one modification, whereby the secondary security element is encoded in the primary security element. The modulation pattern is associated with a modulation pitch and a modulation orientation. The modulation pitch mismatches a decoding pitch associated with the decoding device and / or the modulation orientation mismatches a decoding orientation of the decoding device.

[0083] Any explanations made with regard to the data carrier as such preferably likewise apply to the method of producing the data carrier and vice versa.

[0084] Hence, the present invention provides an encoding approach that enables a decoding in a dynamic and optically variable manner, wherein the encoded secondary security element such as an embedded or hidden image and / or alphanumeric character is decoded or revealed in dynamic fashion combining, for instance via the Moire effect.

[0085] Furthermore, the present invention enables a splitting of the security element into two or more spatial areas which have their dedicated decoding parameters and encoding settings, for instance with a Moire effect having e.g. different direction and speed of motion.

[0086] Furthermore, the present invention enables an encoding in luminance and / or in color space, combining e.g. an orientation and / or extension of the secondary security element such as a text direction with the Moire effect direction for clearer authentication, and similarly matching a spatial expansion along a width direction e.g. a text font size with the Moire band width.

[0087] The dynamic and optically variable aspects enhance the security by making the security element to stand out more clearly and to have clear dynamic effect as a further proof for authenticity.

[0088] The split of the encoding / decoding into e.g. two spatial areas such as halves of the security element such as an image enables combining parts with different graphics / data / font size as well as two distinctly different effects instead of just one.BRIEF DESCRIPTION OF THE DRAWINGS

[0089] 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. 1shows a secure article comprising a data carrier in the form of a data page according to the invention, wherein the data carrier comprises a security element comprising a primary security element that comprises an encoded secondary security element being decoded with a decoding device; Fig. 2shows an enlarged view of the security element according to figure 1, wherein the secondary security element is decoded with the decoding device; Fig. 3shows security elements according to the invention and comprising a primary security element and secondary security elements being encoded into the primary security element in different manners; Fig. 4shows another security element according to the invention comprising a primary security element and an indication of different spatial areas within which the secondary security element can be decoded according to different encodings; Fig. 5shows another security element according to the invention comprising a secondary security element being decoded according to a first encoding in a first spatial area and a second encoding in a second spatial area, wherein the secondary security element is decoded with a decoding device; Fig. 6shows the security element according to figure 5 being decoded with the decoding device when being viewed under different viewing angles, wherein the secondary security element in the different spatial areas exhibit different appearances; Fig. 7shows another security element according to the invention and comprising a primary security element and an encoded secondary security element being decoded with a decoding device, wherein the secondary security element is encoded in different spatial areas; Fig. 8shows another security element according to the invention comprising a primary security element and a secondary security element that is encoded in different spatial areas and that is decoded with a decoding device; Fig. 9shows an illustration of a conceivable modulation pattern according to the invention that can modulate the primary security element; Fig. 10shows another illustration of a conceivable modulation pattern according to the invention that can modulate the primary security element; Fig. 11shows an illustration of a modulation pattern comprising a modulation orientation and a modulation pitch that can modulate the primary security element and a decoding orientation and a decoding pitch of a decoding device that can decode a secondary security element being encoded in the primary security element according to the invention, wherein the modulation pitch and the decoding pitch mismatch one another; Fig. 12shows an illustration of a modulation pattern comprising a modulation orientation and a modulation pitch that can modulate the primary security element and a decoding orientation and a decoding pitch of a decoding device that can decode a secondary security element being encoded in the primary security element according to the invention, wherein the modulation pitch and the decoding pitch as well as the modulation orientation and the decoding orientation mismatch one another; Fig. 13shows a security element comprising a primary security element and an encoded secondary security element according to the invention, wherein a shape and an orientation of the secondary security element are indicated; Fig. 14shows a security element comprising a primary security element that comprises an encoded secondary security element being decoded with a decoding device according to the invention, wherein the decoding device is moved relative to the security element, whereby an appearance of the secondary security element is changing; Fig. 15shows a security element comprising a primary security element that comprises an encoded secondary security element being decoded with a decoding device according to the invention, wherein the decoding device is tilted with respect to the security element, whereby an appearance of the secondary security element is changing; Fig. 16shows a security element comprising a primary security element that comprises an encoded secondary security element being decoded with a decoding device according to the invention, wherein an appearance of the secondary security element changes depending on a viewing angle under which the security element is viewed; Fig. 17shows a security element comprising a primary security element that comprises an encoded secondary security element being decoded with a decoding device according to the invention, wherein an appearance of the secondary security element changes depending on a viewing angle under which the security element is viewed. DESCRIPTION OF PREFERRED EMBODIMENTS

[0090] The figures illustrate various aspects of the security element according to the invention.

[0091] Figure 1 shows a typical embodiment of a secure article 1000 comprising a data carrier 1 according to the invention. In the depicted example, the data carrier 1 is a passport data page that comprises a security element 3. The security element 3 comprises a primary security element 4 in the form of a personal photo and a secondary security element 5 being encoded (i.e. hidden) into the primary security element 4 and that is not visible by naked eye. Instead, the secondary security element 5 is revealed, i.e. decoded, upon decoding with a suitable decoding device 6. Said decoding device 6 can be a separate component such as a decoding lens, or it can be an integral component of the data carrier 1 such as part of another data page of the passport 1000. In the depicted example, the secondary security element 5 comprises alphanumeric characters in the form of the name "Angela Taylor" and the numbers "15", "05" and "95". That is, the secondary security element 5 is split over different spatial areas 7, 8 of the carrier body 1 with the name providing a first secondary-security-element-part 9 being present in one spatial area 7 of the carrier body 1, here on an upper left side, and the numbers providing a second secondary-security-element-part 10 being present in a different spatial area 8 of the carrier body 1, here on a lower right side. Said different spatial areas 7; 8 are sometimes also referred to as "zones" for the sake of simplicity.

[0092] Again in other words, and as also follows from figure 2, the secondary security element 5 comprises here two parts, a first part 9 being provided by the alphanumeric characters in the form of the name "Angela Taylor" and a second part 10 being provided by the and the numbers "15", "05" and "95". As follows from the figure, both secondary security element parts 9; 10 are not fully rotationally symmetric at any angle of rotation. Furthermore, the two secondary security element parts 9; 10 have a different orientation, i.e. the first secondary security element part "Angela Taylor" 9 is oriented according to a first orientation O1 along lines running diagonally upwards, whereas the second secondary security element part "15", "05" and "95" 10 is oriented according to a second orientation O2 along horizontal lines.

[0093] Figure 2 furthermore illustrates a visible effect of encoding (hiding) the secondary security element 5 (typically a personal data) into the primary security element 4 (typically an image such as a photo). The hidden information 5 is invisible by naked eye and only when placing a decoding device 6 over the primary security element 3, wherein the encoded information is revealed in form of text that superposed over darker and brighter bands. These bands are so-called Moire bands B. That is, the primary security element 4 is modulated according to a modulation pattern, and wherein at the location of the secondary security element 5 there is a modification in the modulation pattern, whereby the secondary security element 5 is generated and encoded in the primary security element 4. Said modulation pattern is associated with a modulation pitch MP and a modulation orientation MO. Likewise, the decoding device 6 is associated with a decoding pitch DP and a decoding orientation DO. The depicted bands B are generated because of a mismatch between the decoding pitch DP and the modulation pitch MP and / or because of a mismatch between the modulation orientation MO and the decoding orientation DO.

[0094] Figures 9 to 12 illustrate various examples of conceivable interplays between modulation pitch MP and modulation orientation MO and the decoding pitch DP and the decoding orientation DO. These bands B are moving in certain directions as the decoding device 6 is shifted or titled with respect to the security element 3. In this way a bond between personal information and the photo is created.

[0095] Figure 3 shows that the primary security element 3 can be split into different zones where different modulation will be applied. The zones might be of arbitrary number and shape. The different modulation can be different modulation pitches and different modulation orientations. In other words, the secondary security element 5 can be encoded according to different encodings in different spatial areas 7, 7a, ... 8, 8a, ... 13 of the carrier body 2. Said different spatial areas can be seen as the different zones.

[0096] Figure 4 shows that the spatial areas 7, 7a, ...; 8, 8a, ... or zones might be non-continuous. Here the spatial areas or zone 1 and 2 comprises a number of non-adjacent bands.

[0097] Figure 5 shows different modulations applied to different spatial areas 7, 8 or zones, which leads to a different appearance of the encoded secondary security element 5 upon decoding and when the data carrier 1 is viewed under different viewing angles. Here the difference is in phase of modulation in the spatial areas 7, 8 or zone 1 and 2. As consequence the text in the first spatial area 7 or zone 1 appears brighter comparing to its surrounding while text in the second spatial area 8 or zone 2 appears darker.

[0098] Figure 6 shows that different modulations applied to different spatial areas 7, 8 or zones leads to a different appearance upon decoding with the decoding device 6 and when the data carrier 1 is viewed under different viewing angles. Here the difference is in angle, i.e. an orientation of the modulation in zone 1 and 2. As consequence under certain orientation of the decoding device 6 with respect to the data carrier 1 the secondary security element 5 in the form of the text is visible only in one spatial area or zone (with matching orientation between the modulation orientation MO and the decoding orientation DO), while the effect is completely cancelled out in the other spatial area or zone. Change of orientation of the decoding device 6 with respect to the data carrier 1 may then cause switch when the new modulation orientation of the decoding device matches modulation orientation of the secondary security element 5 in the other zone.

[0099] Figure 7 shows an interplay between the shape of the spatial areas 7, 8, ... or zones and shape of secondary security elements 5. Here the zones are shaped in lines that match, i.e. are arranged at a same location as, the line structure of the secondary security element 5 (text in this case) and different modulation in the zone 1 and 2 generates appearance of alternating bright and dark text lines upon decoding with the decoding device 6 and when the data carrier 1 is viewed under different viewing angles.

[0100] Figure 8 shows that the shape of secondary security element 5 can be chosen to support the artistic design of the spatial areas 7, 8, ... or zones. In this example the secondary security element 5 is chosen as text following the curvature of zone 1 and 2 and producing the alternating text lines appearance. In zone 3 the secondary security element 5 is generated along simple parallel lines.

[0101] Figure 9 illustrates an orientation and a pitch of a modulation function used to modulate the primary security element 4 in simple case of rectilinear periodic function, whereby the modulation orientation MO and the modulation pitch MP of the modulation pattern are generated.

[0102] Figure 10 illustrates an orientation and pitch of a modulation function used to modulate the primary security element 4 in the simple case of rectilinear periodic function.

[0103] Figure 11 illustrates the formation of Moiré bands B as superposition of two slightly "mismatching" periodical structures such as a) periodical modulation of the primary security element 4 resulting in a modulation pitch MP and a modulation orientation MO and b) peridical character of the decoding device 6 associated with the decoding modulation DM and the decoding orientation DO mentioned above .

[0104] Figure 12 illustrates that Moiré bands B can be characterized by a) width BW and the angle BO (i.e. orientation) of the band B and b) its modulation and decoding orientation (also referred to as angle). These are controlled by relative mismatch of the pitch MP; DP or period and an orientation MO; DO or angle of the two periodic structures.

[0105] Figure 13 illustrates that parameters of the Moiré bands can be controlled and matched with a shape and an orientation of the encoded secondary security element 5 to achieve various design goals and effects.

[0106] Figure 14 shows that a position of the Moiré bands B depends on relative position of the two periodic structures asociated with the modulation pattern of the primary security element 3 and that of the decoding device 6. When relative position changes, e.g. when the decoding device 6 is shifted with respect to the data carrier 1 the Moiré bands B move. The displacement of the bands B is typically much larger than movement of the decoding device 6 (Moiré speedup). Continuous tiny movement of the decoding device 6 then produces large, well obeservable continuous movement of the bands B and illusion of movement is created.

[0107] Figure 15 shows that a movement of Moiré bands B can be also produced by slight tilting of the carrier body 2 or by changing of viewing angle under which the data carrier 1 is viewed. This is caused due to the fact that the periodic structure created on a top surface of the decoding device 6, that has certain thickness, that separates the two periodic structures. Due to paralax effect, when viewing angle is changed the relative position of the two structures changes as well.

[0108] Figure 16 shows that various effects can be achieved, for instance the band may interplay with line oriented secondary security element 5 and create brighter and darker lines, with darker and brighter text. The moiré movement might be designed so that the bands moves slowly perpendicularly to the lines and hence the text is slowly changing brightness from dark to bright and vice versa.

[0109] Figure 17 shows that various effects can be achieved, for instance the band may wide so that the whole secondary security element 5 is contained in single band. The moiré movement might be designed so that the band moves fast and hence the hidden element 5 appears to be flashing between dark and bright.LIST OF REFERENCE SIGNS

[0110] 1data carrier 2carrier body 3security element 4primary security element 5secondary security element 6decoding device 7, 7a, ...spatial area 8, 8a, ...spatial area 9first secondary-security-element-part 10second secondary-security-element-part 11spatial area Oorientation O1first orientation O2second orientation MPmodulation pitch MOmodulation orientation DPdecoding pitch DOdecoding orientation Eextension direction Wwidth direction BMoire bands BOMoire band orientation BWMoire band width 1000secure article

Claims

1. A data carrier (1) for a secure article (1000) 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 primary security element (4) and at least one secondary security element (5) being encoded in the primary security element (4), wherein the secondary security element (5) is configured to be decoded via at least one decoding device (6), wherein the secondary security element (5) is configured such that, when being decoded with the decoding device (6), an appearance of the secondary security element (5) changes depending on a viewing angle under which the data carrier (1) is viewed, characterized in that the primary security element (4) is modulated according to at least one modulation pattern, and wherein at a location of the secondary security element (5) the modulation pattern comprises at least one modification, whereby the secondary security element (5) is encoded in the primary security element (4), wherein the modulation pattern is associated with a modulation pitch (MP) and a modulation orientation (MO), and wherein the modulation pitch (MP) mismatches a decoding pitch (DP) associated with the decoding device (6) and / or the modulation orientation (MO) mismatches a decoding orientation (DO) of the decoding device (6).

2. The data carrier (1) according to claim 1, wherein an extension direction (E) and / or an orientation (O) of the secondary security element (5) on the carrier body (2) equals or differs from the modulation orientation (MO) of the modulation pattern, and / or wherein a spatial expansion of the secondary security element (5) along a width direction (W) extending perpendicularly to the extension direction (E) of the secondary security element (5) equals or differs from the decoding pitch (DP) of the decoding device (6) and / or the modulation pitch (MP).

3. The data carrier (1) according to any one of the preceding claims, wherein the change of the appearance of the secondary security element (5) upon changing the viewing angle under which the data carrier (1) is viewed is at least one of: a change in luminescence, a change in colour, a change in intensity, a change in brightness, or a change in reflectance.

4. The data carrier (1) according to any one of the preceding claims, wherein the primary security element (4) is associated with pixel values, and wherein said pixel values in the region of the secondary security element (5) are modulated according to the modulation pattern such, that a difference in appearance of the pixel values of the primary security element (4) and of the secondary security element (5) is created when the data carrier (1) is viewed under different viewing angles while an average appearance of the security element (3) remains unchanged.

5. The data carrier (1) according to any one of the preceding claims, wherein the secondary security element (5) comprises at least a first secondary-security-element-part (9) and a second secondary-security-element-part (10) that are not fully rotationally symmetric and that have different orientations (O1; 02) on the carrier body (2).

6. The data carrier (1) according to any one of the preceding claims, wherein the secondary security element (5) is encoded according to at least a first encoding in at least a first spatial area (7) of the carrier body (2) being generated by the modulation pattern associated with the modulation pitch (MP) and the modulation orientation (MO), and wherein the secondary security element (5) is furthermore encoded according to at least one second encoding in at least a second spatial area (8) of the carrier body (2) by a second modulation pattern modulating the primary security element (4) and being associated with a second modulation pitch and a second modulation orientation.

7. The data carrier (1) according to claim 6, wherein the first encoding differs from the second encoding such that, when being decoded with the decoding device (6), an appearance of the secondary security element (5) in the first spatial area (7) differs from an appearance of the secondary security element (5) in the second spatial area (8), and wherein the appearances of the secondary security element (5) in the first spatial area (7) and the second spatial area (8) change depending on a viewing angle under which the data carrier (1) is viewed.

8. The data carrier (1) according to claim 6 or 7, wherein the decoding pitch (DP) and the decoding orientation (DO) of the decoding device (6) is associated with the first encoding of the secondary security element (5), and wherein the decoding device is furthermore associated with a second decoding pitch and a second decoding orientation, and: - wherein the second modulation pitch matches or mismatches the second decoding pitch, and / or - wherein the second modulation orientation matches or mismatches the second decoding orientation.

9. The data carrier (1) according to any one of claims 6 to 8, wherein the first spatial area (7) and the second spatial area (8) are arranged adjacent to one another or spaced apart from one another on the carrier body (2), and / or wherein a spatial expansion of the first spatial area (7) and a spatial expansion of the second spatial area (8) are the same or different from one another, and / or wherein a shape of the secondary security element (5) in the first spatial area (7) and a shape of the secondary security element (5) in the second spatial area (8) are the same or different from one another.

10. The data carrier (1) according to any one of claims 6 to 9, wherein at least part of the secondary security element (5; 9) being encoded according to the first encoding extends on the carrier body (2) along a first extension direction and / or has a first orientation (O1) and at least part of the secondary security element (5; 10) being encoded according to the second encoding extends on the carrier body (2) along a second extension direction being different from the first extension direction and / or has a second orientation (02) being different from the first orientation (O1).

11. The data carrier (1) according to any one of the preceding claims, wherein at least one of: - the security element (3) is a print and / or coloured; - the primary security element (4) is observable to an un-aided eye; - the secondary security element (5) is non-observable to an un-aided eye; - the primary security element (4) and / or the secondary security element (5) have the shape of a picture and / or an alphanumeric character, or - the primary security element (4) and / or the secondary security element (5) are machine readable.

12. The data carrier (1) according to claim 11, wherein the secondary security element (5) is at least regionally printed along a non-straight and / or arbitrary direction.

13. The data carrier (1) according to any one of the preceding claims, wherein the decoding device (6) is configured to mask and / or magnify and / or suppress at least part of the security element (3) such, that the secondary security element (5) is decoded, and / or wherein the decoding device (6) is a physical decoding device, preferably a lenticular decoding device or a grid-like decoding device, or a digital decoding device.

14. A secure article (1000) comprising or consisting of at least one data carrier (1) as claimed in any one of the preceding claims, the secure article (1000) preferably being an identity card, a passport, a credit card, a smart card, a driving licence, a data page or the like.

15. A method of producing a data carrier (1) for a secure article (1000) such as a passport, the data carrier (1) preferably being the data carrier 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 primary security element (4) and at least one secondary security element (5) being encoded in the primary security element (4), wherein the secondary security element (5) is configured to be decoded via at least one decoding device (6), wherein the secondary security element (5) is configured such that, when being decoded with the decoding device (6), an appearance of the secondary security element (5) changes depending on a viewing angle under which the data carrier (1) is viewed, characterized in that the primary security (4) is modulated according to at least one modulation pattern, and wherein at a location of the secondary security element (5) the modulation pattern comprises at least one modification, whereby the secondary security element (5) is encoded in the primary security element (4), wherein the modulation pattern is associated with a modulation pitch (MP) and a modulation orientation (MO), and wherein the modulation pitch (MP) mismatches a decoding pitch (DP) associated with the decoding device (6) and / or the modulation orientation (MO) mismatches a decoding orientation (DO) of the decoding device (6).

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