EP2890568B1 - Security document having a multicolored and two-sided security feature - Google Patents

Description

The invention relates to a security document and a method for its production with a preferably colored security feature and a verification method.

A large number of security documents are known from the prior art. These include, for example, identity cards, passports, driver's licenses, identification cards, visas, but also labels and packaging protected against counterfeiting and other types of value documents such as banknotes, shares, securities, to name just a few.

Security documents have in common that they include at least one feature that makes unauthorized production, imitation, falsification or the like at least significantly more difficult or even impossible. Such features are referred to as security features. Physical configurations of security features are also referred to as security elements. In this sense, every security document that necessarily includes at least one security feature also represents a security element.

With a large number of security documents, it is desirable to store individual information in the individual security documents, which is assigned, for example, to a person to whom the security document is assigned. In the case of a passport, such individual information is, for example, a name, a date of birth, a place of residence or biometric data such as a facial image, a fingerprint or the like. Individual information associated with an individual is also referred to as personal information. The process of incorporating personal information into a security document is also referred to as personalization.

In addition to such individual or personal information, security documents of a class, for example a passport of a state, usually also have a large number of other security features that make imitation, falsification, duplication and the like more difficult and/or impossible and also verification of the document as a real document. These are therefore usually the same for all documents

Class, i.e. the same for all passports of a country, for example. These security elements are generally integrated into the security document in a central security document production facility. In some production processes and documents, the personal and/or individual information is already stored in the security document during the central production. In other embodiments, however, only one security document blank is produced in the central production, which is then individualized or personalized centrally or decentrally with individual and/or personal information.

From the WO 2011/051668 A1 discloses a lenticular lens security device comprising an array of focusing lenticular elements arranged over a corresponding array of pairs of imaging strips such that from a first viewing direction a first imaging strip is visible when viewed through a respective focusing lenticular element and from a second viewing direction a second image swath, distinct from the first image swath, is visible from each pair when viewed through one of the focusing lenticular elements.

From the DE 10 2010 048 772 A1 a method for producing a security document with a security feature dependent on the viewing angle and such a security document are known. The method described there comprises the steps of: printing print information onto a substrate layer; Integrating the printed substrate layer into a document body and introducing microlenses into the surface of the document body, the microlenses being introduced after the printed substrate layers have been integrated into the document body, in that the print information integrated in the document body is optically recorded and at least one feature of the recorded print information is evaluated, and on the basis of the evaluated feature one or more tools are aligned relative to the document body and then the microlenses are introduced into the surface with an exact register for the integrated print information. The printed information is preferably colored and thus evokes different color impressions in an observer.

From the DE 103 58 784 A1 a data carrier is known in which markings in the form of patterns, letters, numbers and/or images are introduced by a laser beam, which are visible due to local changes in the optical properties of the data carrier caused by the laser beam and resulting from material transformations. The data carrier comprises a laser-sensitive recording layer which is transparent in the visible spectral range and is provided with a surface relief in the form of a lenticular grid. The markings are introduced into the recording layer with the laser beam from different directions through the lenticular grid and are recognizable when viewed later from the same directions. The data carrier is transparent at least in the area where the markings are introduced. The local changes in the optical properties of individual picture elements resulting from the material transformations are at least partially identical for the different directions. If ever picture elements with different optical properties such. B. different shades of gray via different blackenings, so from every direction all different blackenings and thus types of picture elements can usually be seen. A given gray level does not occur under only one of the directions.

In order to enable decentralized individualization and/or personalization, the technical effort involved in storing the information must be kept as low as possible. Printing methods for printing information onto an otherwise completed or largely completed security document blank are therefore particularly suitable. Information stored in this way, however, is relatively vulnerable to tampering because it is formed on the surface of a document body. Therefore it is necessary to save the Secure information related to verification of authenticity. Protection against manipulation is also desirable for information stored centrally in a document body, which can be stored, for example, inside the document body by printing a substrate layer which is laminated with other substrate layers to form the document body.

The invention is therefore based on the technical object of creating an improved security document, a method for its production and a verification method which do not have or reduce the disadvantages known from the prior art.

The invention is based on the idea of storing personalizing and/or individualizing information, possibly also non-personalizing and/or non-personalizing information, in a document body. In this case, the storage takes place by means of at least two different types of picture elements, which can each be arranged at grid positions of a picture element grid assigned to the respective picture element type. The thus at least two picture element grids are matched to one another in such a way that a corresponding grid position of another picture element grid corresponds to each grid position of one picture element grid. The mutually corresponding grid locations of the picture element grids are adjacent to one another in the security document. The raster positions of the various image element rasters are preferably offset relative to one another laterally with respect to a document surface, ie are not arranged in a superimposed manner. The information is stored in the body of the document in a window area which is designed to be transparent so that it can be looked through without the stored information being present. The information is stored in the body of the document in such a way that it is perceptible when optically capturing it from above. The graphic information can thus, for example, be printed on the top or formed inside the document body, for example by printing the information on a substrate layer before this is joined to further substrate layers to form the document body. To protect the graphic information, a lenticular grid is formed on the back of the document body, which is adapted to the picture element grid. Both with regard to the arrangement and the configuration of the grid, the lens grid is adapted in such a way that at least two preferred detection directions regarding a detection of the graphic information through the lenticular screen from the back of the document body, under which only the picture elements of one type are perceptible. Under a preferred detection direction of the at least two preferred detection directions, only the picture elements of one type are perceptible and under another preferred detection direction of the at least two preferred detection direction, only the picture elements of a different type of picture elements are perceptible.

The graphic information is preferably designed in color by using monochrome picture elements of a color system to create the graphic information. If, for example, cyan-colored, magenta-colored and yellow-colored image elements are used, pixels of any desired color impression of the CYM color system can be generated from three raster points that are assigned to one another. Thus, it is possible to store full color graphic information in the document body using picture elements of three types. The lenses of the lenticular grid formed on the back are arranged with respect to the individual grid positions of the different picture element grids such that only the picture elements of one type, ie in this example a basic color of the color system, can be detected through the lenses in different detection directions. Thus, under the different preferred directions of detection of an observation of the optical detection of the graphic information through the back of the security document, ie through the lens raster, color-separated extracts of the stored graphic information are obtained. This makes the forgery and/or falsification of the security document significantly more difficult, since both adding image elements to change the information content and delaminating and reassembling them with the lenticular raster is almost impossible without subsequent individual image elements of one type at raster points of an image element raster of another Type exist at least in relation to the intended arrangement of the individual grid points based on the lenticular grid. This means that such image elements are conspicuous during verification of the security document in one of the preferred detection directions, since they deviate from the optical properties of the image elements of the type that should only be detectable in this preferred detection direction. After delamination, manipulation of the graphic information and reassembly, is an entire pixel grid shifted in relation to the lenticular grid, no image elements of the expected type can be perceived under one preferred detection direction.

definitions

A graphic unit is regarded as a picture element which has a defined value with regard to at least one optical property. Pixels of one type all have the same optically detectable property. Preferably, this property identifying a type of pixel is a color associated with the pixel of that type.

A grid is a geometric structure that reveals an order pattern at least along one spatial direction. Patterns preferably reveal a regularity in at least two mutually orthogonal directions. As a rule, grids are made up of grid points, which are thought to be point-like, with the individual grid points being able to be assigned to a cell and the grid being built up by a periodic repetition of the cell structure. It is possible that individual dimensions of the cell are varied. A simple example of a grid is a matrix of rows and columns. The individual cells that result, for example their center points, then form grid positions. However, the crossing points of vertical and horizontal lines parallel to one another can also be regarded as grid points of a grid made up of rectangular cells. In this case, for example, a length of the rectangles can be varied systematically in the grid along a designated direction, so that, for example, the perpendicular lines are at greater distances from the edges than the perpendicular lines in a center of the grid.

Similar grids are grids that have a geometric structure that corresponds to one another, preferably an almost identical structure, and that are shifted relative to one another only with regard to their positioning in space.

Grid points corresponding to one another of such grids of the same type are those grid points which have a minimum distance from one another. If one starts from a raster position of a raster, then the adjacent raster position of another raster is that raster position which has a minimum of the first raster position.

If there are several nearest neighbors, an arbitrary determination is made for a spatial direction in which the nearest neighbor should also be located for the other grid locations of one grid.

The mutually adjacent, mutually corresponding raster positions of different picture element rasters are offset laterally, e.g. in relation to the front side of the document body.

All printing methods known in the field of security documents are understood to be printing methods. These include, for example, inkjet printing, retransfer printing, D2T2 printing, offset printing and other printing processes.

All those surface structures are understood to be lenses which, due to the geometric shape of an interface between media of different refractive index, have an imaging property for light caused by light refraction.

Preferred Embodiments

In particular, a security document is created which comprises a document body which has a front side and an opposite back side, the document body being transparent at least in a window area for a look-through view, and wherein on or in the document body in the window area a Graphic information perceptible from the front is stored, the graphic information being formed by means of at least two different types of picture elements, each of the at least two different types of picture elements being assigned a picture element grid having grid locations and the picture elements of one type being arranged only at grid locations of the picture element grid assigned to the type are, and wherein the pixel grids have mutually corresponding grid locations which are arranged adjacent to one another in the document body, it being provided that at the R A lenticular grid is formed on the back of the document body, with the image element grids being formed and arranged relative to each other and to the lenticular grid in such a way that there are at least two preferred detection directions with regard to the back of the document body, among which by the Lenticular screen through only the pixels of one type of graphic information can be detected.

The image elements of one type each have a uniform optically perceptible impression. In particular, a color is assigned to the individual types of picture elements. The associated colors are preferably colors of a color system, for example a cyan-magenta-yellow or cyan-magenta-yellow-black color system or alternatively a red-green-blue (RGB) or red-green-blue Black (RGBK) color system.

Furthermore, a method for producing a security document is created, comprising the steps: producing a document body which is transparent at least in a window area between a front side and a back side of the document body, storing graphic information perceptible when viewing the front side from above in the area of the window on the Front side or in the document body, wherein the graphic information is formed by means of at least two different types of picture elements, each of the at least two different types of picture elements being assigned a picture element grid having grid locations and the picture elements of one type only at grid locations of the picture element grid assigned to the type are arranged and wherein the pixel grids have corresponding grid locations which are arranged adjacent to one another in the document body, wherein on the reverse side of the document enkörpers a lenticular raster is formed and the image element raster is formed and arranged relative to each other and to the lenticular raster that at least two preferred detection directions exist with respect to the back of the document body, under which only the image elements of one type of graphic information can be detected through the lenticular raster. The image elements of one type are configured identically with regard to at least one optically detectable or perceptible property and differ from all image elements of the other different types of image elements at least in this optically detectable property. Such a security document can be verified, for example, using a method in which the graphic information is recorded and evaluated under a top view of a front side of the document body and additionally one from at least two predetermined preferred recording directions with respect to the back side of the document body Consideration of the graphic information is made through the lenticular grid on the back of the document body, and it is checked whether only the image elements of one type are detected under the at least two preferred detection directions. If this is the case, a positive verification decision is made, if necessary, additionally depending on the evaluation of the graphic information itself. Otherwise, a negative verification decision is made. Since the image elements of one type always have an optically detectable property with regard to which they are identical and differ from the image elements of other types, it can always be checked during verification whether, with regard to an optically detectable property, there is only one of the preferred detection directions for all detectable image elements uniform expression is found, which does not occur under a different preferred detection direction of the at least two preferred detection directions.

In a preferred embodiment, the graphic information is formed using the picture elements of the at least two different types of picture elements in such a way that the information content of the graphic information cannot be derived from the picture elements of one type. If the graphic information includes lettering made up of alphanumeric characters, then the entire lettering cannot be removed from any of the images captured through the lens grid in one of the preferred directions of detection. If the information includes a bar code, then none of the recorded images can be taken from all the positions and widths of the bars of the bar code.

In an embodiment that is even more difficult to counterfeit, the graphic information comprises, for example, alphanumeric characters and the graphic information is designed in such a way that none of these characters can be recognized under one of the preferred detection directions when viewing or detecting an image through the lenticular grid on the back of the document body. In each case, a picture element pattern of the picture elements of a type of picture elements is obtained from which no cognitively detectable information can be derived. Such a picture element pattern is suitable for machine verification in which such picture element patterns are compared with one or more predetermined reference patterns. For a positive verification, which indicates that the security document is authentic and unadulterated, a match of the captured image element pattern with the reference pattern be required or that a predetermined number of image elements correspond to pattern elements of the comparison pattern or that a corresponding detected image element of the image element pattern exists for each pattern element or a predetermined number of pattern elements of the comparison pattern. Alternatively or additionally, the optically detectable property of the detected image elements can be evaluated and checked for an image element pattern.

The picture element grids and the lenticular grid preferably have a cell structure, the cells of the individual picture element grids corresponding to one another. For example, the cells have a rectangular structure, particularly preferably a square structure. However, it is also possible to choose a triangular or hexagonal cell structure. A cell structure of the lenticular array often differs in a dimension of the cell structure, but the geometric shape is often the same.

The graphic information is particularly preferably stored by means of a printing process. This can be done, for example, by printing the graphic information on the front of a document blank in the area of the window. Alternatively, a substrate layer or different substrate layers can be printed, which are aligned with one another and joined to form the document body, for example laminated with one another. A particularly good lateral alignment of the individual picture elements of the different types, i.e. the different picture element grids relative to one another, is obtained if the picture elements of different types are printed either on the same substrate layer surface or on different surfaces of the same substrate layer.

The graphic information can also be in the form of a hologram in which the different types of picture elements are exposed into the hologram using different wavelengths (ie colors). The different types of picture elements are each formed at raster points of the picture element raster assigned to the type. The pixel grids have corresponding grid locations. The picture element grids are laterally offset from one another.

The lenticular screen is preferably formed after the graphic information has been stored in the security document. For this purpose, the graphic information is optically recorded and, for example, a sonotrode of an ultrasonic embossing system is aligned relative to the security document blank and the lens raster is then formed by means of an ultrasonic embossing process. This makes it possible to achieve precise alignment of the lenticular grid with respect to the picture element grid. Other embodiments can provide other surface treatment methods, for example ablation methods, in particular laser ablation methods, in order to introduce the lenticular grid into the back of the document body.

In other embodiments, it can be provided that the graphic information is only stored in the document body after the lenticular grid has been formed. For this purpose, directed light radiation can be directed in one or more directions, for example the preferred detection directions, onto the underside of the document body and a light penetration of the radiation through a surface to be printed can be determined. The image elements are then formed in the document body in an appropriately adapted manner. Parallax errors occur when the graphic information is optically captured through the lens grid, in particular when the graphic information and thus also the lens grid have a greater lateral extent in relation to a predetermined target viewing distance or a target viewing position. In one embodiment, it is therefore provided that the distances between the raster points of the picture element raster and/or the lens raster vary at least along one spatial direction in order to take parallax into account when capturing the graphic information from a target capturing position and to compensate for parallax errors.

In yet another embodiment, the picture element grid and/or the lenticular grid, which have a cell structure, are designed such that an extent of the cells of the picture element grid and/or the cells of the lens grid is or will be varied along at least one spatial direction in order to avoid parallax for a To consider stereo detection of a target position for at least one of the at least two preferred detection directions. Such an embodiment is particularly suitable for being verified by a person whose two eyes are designed for optical detection and thus stereographic detection.

Preferably, the target detection position is defined relative to a midpoint between the eyes at a target distance perpendicularly across the back of the security document. The lenticular grid and the picture element grid are aligned and arranged relative to one another in such a way that a tilting about an axis lying in the plane of the security document, which is oriented perpendicularly to the line connecting the eyes, is tilted, so that viewing from the at least two preferred detection directions can be set . In one embodiment, there are four preferred detection directions, each of which can detect one type of image element. In the above-described embodiment, the third and fourth preferred detection direction are preferably designed such that the third and fourth preferred detection direction can be set by tilting about an axis parallel to the interpupillary distance and axis of rotation lying in the document.

Fig. 1

eine schematische Draufsicht auf ein Sicherheitsdokument;

Fig. 2a

eine schematische Schnittansicht durch ein Sicherheitsdokument mit außen aufgebrachter grafischer Information;

Fig. 2b

eine schematische Schnittansicht durch ein Sicherheitsdokument mit innenliegend gespeicherter grafischer Information;

Fig. 3

eine schematische Darstellung einer erfassten Ansicht unter einer ersten Vorzugserfassungsrichtung;

Fig. 4

eine schematische Darstellung einer unter einer anderen Vorzugserfassungsrichtung erfassten Abbildung des Sicherheitsdokuments nach Fig. 1;

Fig. 5

eine schematische Darstellung zur Erläuterung der Verifikation eines Sicherheitsdokuments;

Fig. 6

eine schematische Darstellung zur Erläuterung eines Verfahrens zum Herstellen eines Sicherheitsdokuments.

The invention is explained in more detail below with reference to a drawing. Here show:

1

a schematic plan view of a security document;

Figure 2a

a schematic sectional view through a security document with externally applied graphic information;

Figure 2b

a schematic sectional view through a security document with internally stored graphic information;

3

a schematic representation of a detected view under a first preferred detection direction;

4

a schematic representation of an image of the security document captured under a different preferred direction of capture 1 ;

figure 5

a schematic representation to explain the verification of a security document;

6

a schematic representation to explain a method for producing a security document.

In 1 a schematic plan view of a security document 1 is shown. This includes a document body 2, which is preferably made of different substrate layers based on plastic. However, embodiments are also possible in which the document body consists of a monolithic block of plastic. The document body 2 is designed in such a way that in a window area 3 it is possible to look through from a front side 9, which faces the viewer, to a back side, which faces away from the viewer. For example, the document body 2 can be made of transparent plastic layers, for example preferably made of polycarbonate layers. An object through which a detection and/or imaging of information according to geometric optics is possible is considered to be transparent.

Graphic information 4 is stored on the front side 9 or inside the document body 2 . This is formed from picture elements of a first type 5 and picture elements of a second type 6 . The picture elements of the first type 5 are arranged at raster points 25 of an associated picture element raster 15 . Correspondingly, the picture elements of the second type 6 are arranged only at grid locations 26 of a second picture element grid 16 . The pixel grid 15 and the pixel grid 16 thus have grid locations 25 and 26, respectively, arranged at regular intervals. For each raster point 25, for example the raster point 25', there is a corresponding raster point, for example 26' of the other picture element raster. These are arranged in the document body 2 adjacent to one another. The corresponding raster points 25', 26' thus have the smallest distance from one another to a raster point of the other picture element raster 5, 6. If a raster point 25 of a pixel raster 15 has the same distance to several raster points 26 of another pixel raster 16, a direction, which is indicated here by the arrow 31, is defined in order to define adjacent raster points 25′, 26′. This specification is of no real practical importance and is included here for explanation purposes only.

The picture elements of the first type 5 and the picture elements of the second type 6 differ with regard to at least one optically perceptible property, for example their Colour. In this case, the picture elements of the same type each have the same optical property. In the illustrated embodiment, only picture elements of the first type 5 and a second type 6 are shown. However, it will be understood by those skilled in the art that embodiments in which, for example, full-color graphic information is to be stored preferably comprise at least three types of image elements, more preferably even four types of image elements. Thus, in such a particularly preferred embodiment, there are four pixel grids. A pixel raster for each type of pixel. In such a particularly preferred embodiment with four picture element grids, the picture elements assigned to the picture element grids preferably have the colors of a color system, for example the colors cyan, magenta, yellow, black or the colors red, green, blue and black. It is thus possible to generate full-color graphic information via color subtraction or color addition.

The image elements are preferably designed so small in terms of their size that they can no longer be resolved as individual image elements by a human observer at a viewing distance of, for example, 15 to 30 cm. At the back 10, which when viewed 1 facing away from the viewer, lenses or lens elements arranged in a lens grid are formed in the window area 3 . These are adapted to the picture element grid and the picture elements formed at the grid locations in such a way that there are at least two preferred detection directions for optical detection with regard to the back, in which the graphic information 4 can be detected through the lenses of the lens grid in such a way that under one of the preferred detection directions only the picture elements of one picture element type are perceptible. In embodiments in which four picture element types are used, the lenses are preferably designed and the picture element grids are aligned and arranged with respect to the lens grid in such a way that four preferred detection directions exist and one type of picture element can be detected among each of these. While one perceives the graphic information 4 in full color when viewing the front side from above or also when viewing transmitted light from the front side, when viewing the back side from one of the preferred detection directions, one can only detect that part of the graphic information that is made with the help of one type of picture elements is trained. This preferably gives different color extracts of the graphic information 4.

In Figures 3 and 4 the two views that can be seen in the two preferred directions of detection of the security document are shown schematically 1 detected.

In Figure 2a a sectional view through a window area 3 of a security document 1 is shown schematically. In the illustrated embodiment, the picture elements 5, 6 are formed on the front side 9 of the document body 2, which is assembled from different substrate layers 41, 42, for example. Lens elements 51 can be seen on the underside 10 of the document body 2, which are arranged according to a lens grid 50, which is designed and oriented to match the picture element grid 25, 26. Also entered are the two preferred detection directions 65, 66, among which, for example, those in Figures 3 and 4 illustrated views of the security document 1 are detectable.

In Figure 2b a schematic sectional view of a modified security document 1 in the area of the window area 3 is shown. In this embodiment, the document body 2 is formed from three substrate layers 41-43. A top substrate layer 41 serves as a cover layer. A middle substrate layer 42, which is formed from a transparent and, for example, laser-capable material, is printed on an upper side with the graphic information 4, which is formed by means of the picture elements 5, 6. A bottom substrate layer 43 is laminated to the top and middle substrate layers 41, 42 to form the document body 2. The substrate layers 41 to 43 are preferably all produced on the basis of the same polymer, so that they can be combined particularly well to form a document body 2 in a lamination process. In addition, all substrate layers 41 to 43 are preferably transparent.

On the back 10 of the document body 2, lens elements 51 are again formed in the lens grid 50, through which the image elements of one type of graphic information 4 can be detected from the preferred detection directions 65, 66. In the illustrated embodiment according to the sectional drawings of Figures 2a and 2b , the lens elements can be cylindrical lenses, for example. However, spherical lenses can also be arranged in a regular grid just as well. In another preferred embodiment, hexagonal lenses are used, which enable a separation of graphic information formed in full color into the different color separations. In order to avoid parallax errors, either grid distances of the picture elements in the picture element grid to edges of the graphic information and/or the lens elements of the lenticular grid can have different distances than in the center of the lenticular grid or the graphic information in order to compensate for this. In one embodiment, this compensation takes place in such a way that stereoscopic detection, such as that performed by a human observer, is also possible without parallax for the individual picture elements of the different types under different preferred viewing directions.

In figure 5 a perspective view of a window area 3 of a security document 1 with a security document body 2 is shown schematically. The same technical features are provided with the same reference symbols in all figures. The graphic information 4 is again formed by means of image elements of two types 5, 6. Adapted for this purpose, lens elements 51 are arranged in a lens grid 50 so that two preferred viewing directions 65, 66 exist in this case symmetrically to a surface normal 70 of the back 10 of the document body 2. The lenses 51 of the lens grid 50 are designed, for example, as cylindrical lenses. An axis of rotation 71, which runs parallel to a longitudinal axis of the cylindrical lenses, can be used as an axis of rotation for the document body 2 in order to tilt the security document 1 for a stationary observer so that, from the back, he can alternately see the security document 1 under the first preferred detection direction and considered the second preferred direction of detection. The two recorded views for the two different preferred directions of recording are indicated schematically. If the document is correctly executed and not manipulated, only the image elements of one type 5 (solid circles) are to be detected in one preferred detection direction 65 and only the image elements of the other type 6 (open circles) are to be detected in the preferred detection direction 66 . This is indicated schematically at the bottom left and right. Due to the observation from the back, the pieces of partial information are recorded as a “mirror image” of the graphic information 4 . If, on the other hand, the security document 2 is viewed from the front 9, the graphic information 4 is captured completely, for example in full color. This is above in figure 5 implied.

Based on 6 the production of a security document 1 is to be briefly explained schematically. First, different substrate layers 41 to 43 provided. Preferably these are all made of a transparent polycarbonate material, for example. The graphic information 4 is printed on the middle substrate layer 42 using first picture elements 5 and second picture elements 6 . The first picture elements 5 are each formed only at raster points 25 of a first picture element raster 15 . Correspondingly, the image elements of the second type 6 are each formed only at grid locations 26 of a second image element grid 16 . Due to the small dimensions of the picture elements 5, 6, it is irrelevant that the picture elements can only be arranged at the grid locations 25, 26 which “belong” to the picture element grid 15, 16 assigned to them.

After the graphic information 4 has been applied, in particular printed, onto the middle substrate layer 42, the various substrate layers 41 to 43 are stacked one on top of the other and connected to form a document body 2. This is preferably done in a high-pressure, high-temperature lamination process. Then the graphic information 4 formed in the document body 2 is detected by means of an optical detection device 90 and the document body 2 is aligned with the graphic information 4 with respect to a sonotrode 91 of an ultrasonic embossing device 100 . As soon as the sonotrode 91 is correctly aligned with respect to the graphic information 4, the lenticular grid 50 is embossed into the back 10 of the security document 1, i. H. of the document body 2, embossed. A security document 1 is obtained in which the graphic information can be completely optically recorded on the front side 9 . In at least two preferred directions of detection 65, 66, only the image elements of one type 5 or 6 of the graphic information 4 can be detected in the window area 3 through the lens grid 50.

It will be understood by those skilled in the art that only exemplary embodiments are described here and that other lens shapes and grids are possible. In the embodiments selected here, the grids are each based on a square cell. However, other cells, each having grid locations formed at their characteristic vertices, may be selected to form corresponding pixel grids or lenticular grids.

Reference List

1

security document

2

document body

3

pane

4

graphic information

5

picture elements of a type

6

picture elements of a different type

9

front

10

back

15, 16

picture element grid

25, 26

grid points

25', 26'

corresponding grid positions

31

Arrow

41-43

substrate layers

50

lenticular

51

lens elements

65, 66

preferred detection directions

70

surface normal

71

axis of rotation

90

optical detection device

91

sonotrode

100

ultrasonic embossing device

Claims (10)

1. Security document (1) comprising a document body (2) with a front side (9) and an opposing back side (10), wherein the document body (2) is transparent in at least one window region (3) for transmitted light observation, and wherein, when observing the front side (9) from above, on or in the document body (2), in the window region (3) is stored an item of detectable graphic information (4), wherein the graphic information (4) is formed by means of at least two different types of image elements (5, 6), wherein each of the at least two different types of image elements (5, 6) is allocated with a pixel grid (15, 16) comprising grid positions (25, 26), and the image elements (5, 6) of one type are allocated only to grid positions (25, 26) of the pixel grid (15, 16) allocated to that type, and wherein the pixel grid (15, 16) comprise grid positions (25', 26') which correspond to one another, and which are arranged adjacent to one another in the document body (2), characterised in that
   the image elements (5) of one type are all configured as identical in respect of at least one optically detectable property, and, in respect of this at least one optically detectable property, differ from image elements (6) of a different type of image element (6) of the at least two different types of image elements (5, 6), and on the back side (10) of the document body (2) a lenticular screen (50) is formed, wherein the pixel grids (15, 16) are formed in such a way, and arranged relative to the lenticular screen (50) in such a way, that at least two preferential detection directions (65, 66) exist in respect of the back side (10) of the document body, under which, through the lenticular screen (50), in each case only the image elements (5, 6) of one type of the graphic information (4) are detectable.
2. Security document (1) according to claim 1, characterised in that the pixel grid (15, 16) and the lenticular screen (50) exhibit a cell structure, wherein expansions of the cells of the pixel grids (15, 16) and/or of the cells of the lenticular screen (50) vary along at least one spatial direction, in order to take account of a parallax at the detection of the graphic information of a reference detection position.
3. Security document (1) according to claim 1 or 2, characterised in that the variation in the expansion of the cells of the pixel grids (15, 16), and/or of the cells of the lenticular screen (50) along the at least one spatial direction, takes place in such a way that a parallax is taken into account for a stereo detection of a reference position for at least one of the at least two preferential detection directions (65, 66).
4. Security document (1) according to any one of claims 1 to 3, characterised in that the image elements of one type (5, 6) exhibit the same optical property.
5. Method for producing a security documents (1), comprising the steps:

   producing a document body (2), which is transparent at least in a window region (3) between a front side (9) and a back side (10) of the document body (2);

   storing an item of detectable graphic information (4) when viewed from above of the front side (9) in the window region (3) on the front side (9) or in the document body (10), wherein the item of graphic information (4) is formed by means of at least two different types of image elements (5, 6), wherein an pixel grid (15, 16) comprising grid positions is allocated to each of the at least two different types of image elements (5, 6), and the image elements of one type (5, 6) are allocated only to grid positions (25, 26) of the pixel grid (15, 16) allocated to that type, and

   wherein the pixel grids (15, 16) comprise grid positions (25', 26') which correspond to one another, and which are arranged adjacent to one another in the document body (2),

   characterised in that

   the image elements (5) of one type are all configured as identical in respect of at least one optically detectable property, and, in respect of this at least one optically detectable property, differ from image elements (6) of a different type of image elements (6) of the at least two different types of image elements (5, 6), and on the back side (10) of the document body (2) a lenticular screen (50) is formed, wherein the pixel grids (15, 16) are formed in such a way and arranged relative to the lenticular screen (50) in such a way that at least two preferential detection directions (65, 66) exist in respect of the back side (10) of the document body (2), under which, through the lenticular screen (50), in each case only the image elements of one type (5, 6) of the graphic information (4) is detectable.
6. Method for producing a security document (1) according to claim 5, characterised in that the image elements of one respective type exhibit a basic colour of a colour system.
7. Method for producing a security document (1) according to claim 5 or 6, characterised in that the graphic information (4) is configured as coloured, and under the at least two preferential detection directions (65, 66) in each case a colour extract of the graphic information (4) is detectable.
8. Method for producing a security document (1) according to any one of claims 5 to 7, characterised in that the lenticular screen (50) is introduced into the back side (10) by means of ultrasonic embossing.
9. Method for producing a security document (1) according to any one of claims 5 to 8, characterised in that the graphic information (4) is printed by means of a printing method onto the front side (9) or onto a surface of a substrate layer (42), which is laminated to other substrate layers to the document body (2).
10. Verification method for a security document (1) in accordance with any one of claims 1 to 4, characterised in that, when viewed from above of a front side (9) of the document body (2), the graphic information (4) is detected and assessed, and, in addition, under at least two preferential detection directions (65,66), with regard to the back side (10) of the document body (2), an observation of the graphic information (4) is carried out through the lenticular screen (50) on the back side (10) of the document body (2), and a check is carried out as to whether, under the at least two preferential detection directions (65, 66), in each case only the image elements of one type (5, 6) are detected, and, inasmuch as this is the case, a verification decision is taken, and, if appropriate, additionally dependent on the evaluation of the graphic information itself.

Images