Secured document

Abstract

The invention relates to a secured document (100) comprising: a substrate (101) partially covered in at least two, preferably non-overlapping regions with an additional layer, wherein a first effect layer (104) made of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflectance coefficient, is applied to at least a first substrate region (106), and a second print layer (103) made of a reflective, color, high-viscosity coating material, which modifies the substrate (101), is applied to at least a second substrate region (107); and wherein on at least the first region (106) of the substrate there is a first security element (102) which is an embossed optical element (108) comprising an embossed structure made by the gravure method in the form of a grid (400) of cells (401), preferably equilateral cells, most preferably square cells, wherein a single cell (401) corresponds to a single point of the first security element (102) forming, together with the remaining points of the grid, a globally perceptible, information-bearing first security element (102), and in which cells (401) there are sub-images (403) formed by convex embossed lines (402) parallel to the remaining ones present in the cell, having a predetermined height (h) in relation to the surface of the substrate (101) between the lines (402), modified with a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflectance coefficient, which lines (402) in each of the cells (401) of the grid (400) are parallel to each other, and the angle of inclination of the lines relative to the selected axis of symmetry, identical for all cells, of the first security element (102) defined in the plane of the substrate (101) is constant within each of the cells (401) of the grid (400) and varies within the range from 1 to 180°, and the number of lines (402) in each of the cells (401) of the grid (400) is equal to or greater than three and the maximum distance measured between the most distant points of each of the cells (401) does not exceed 1 mm, preferably is less than 0.7 mm, more preferably is less than 0.5 mm and most preferably is less than 0.1 mm.

Description

[0001] Secured document

[0002] Description

[0003] The present invention relates to a secured document containing an integrated security feature comprising an optically variable element with a visual effect of variation or movement when changing the angle of its observation, and an ink element, preferably multi-colored, wherein the optically variable element contains a hidden image encoded in an appropriately computer- designed arrangement of embossed sub-areas.

[0004] BACKGROUND ART

[0005] Secured documents are documents containing numerous elements aimed at preventing forgery and unauthorized modification thereof. Such documents are most often used to confirm the existence of specific rights, legal relationships, or legal events expressed on specific information carriers. Secured documents, regardless of their function and intended use, include at least a substrate and a security element applied to it. Such a substrate may be a cellulose or cotton substrate, such as paper, or a plastic substrate, such as polypropylene (BOPP). The substrate may also be a hybrid substrate, such as a cellulose-plastic substrate. Many a time, secured documents contain important information, in particular personal data of the holder of such a secured document, thus serving as data carriers, especially of personal data when the secured documents are used as identification documents.

[0006] Such identification documents with security features can be successfully used to establish a person’s identity (identity documents and passports), authorize a specific person to perform specific activities (for example, a driving license or an ID card confirming specific qualifications, such as attorney or legal counsel qualifications), confirm ownership rights or the right to future income (securities), or constitute the basic means of payment in circulation (banknotes). They can also have collector’s value in the form of, for example, occasional securities or stamps. Regardless of their function, secured documents are now an indispensable element of everyday life in all developed countries.

[0007] Unfortunately, as their importance continues to grow, so does the risk of forgery. There-is a reasonable expectation that a person relying on the authenticity of a particular document enjoys the greatest possible probability, preferably certainty, that the document has not been altered and / or forged. Therefore, it is extremely important and desirable to provide security measures that effectively prevent manipulation and forgery of secured documents, as well as security measures that are easy to obtain and, at the same time, effective in preventing the introduction of inauthentic documents into circulation.

[0008] In this field, security features commonly used include solutions, where a security feature incorporated into the document is characterized by changing color or image when viewed from different angles relative to the light source. These security features utilize various optical phenomena, such as diffraction or reflection of incident light, to provide dynamic visual effects that are difficult to counterfeit. Their particular advantage is the easy and quick verification of a document’s authenticity without the need for specialized equipment. These security features include, in particular, holograms, optically variable devices (OVDs), optically variable inks (OVI®), or engraved or gravure-printed, convex, and tactile images including numerous patterns or motifs that provide non-uniform, three-dimensional, and multi-tonal effects that vary depending on the viewing angle.

[0009] Such angular-effect security features play a special role in authenticating the security documents provided with them, as they cannot be easily reproduced, for example, by simple copying, even using state-of-the-art copiers, or by modifying the surface of the document provided with them. Furthermore, the angular-effect security features allow for the insertion of hidden elements into a document being secured.

[0010] The prior art knows security features with an angular effect, which include images consisting of at least two sets of parallel lines located at different angles to each other, which lines are visible when the substrate on which they are applied is tilted relative to the incident light source. This creates an image consisting of lines parallel to the light source, and lines arranged at an angle to the visible lines are perceived as a darker color / tint. For example, the publication PL234566B1 discloses a security element with an angular effect in the form of a latent image, consisting of:

[0011] - a background layer applied to a substrate of the security and / or value document, said background layer consisting of: at least one sequence of equidistant first lines, said sequence comprising at least two lines of different colors, wherein the color of the background may be one of the colors of the sequence of the first lines, and the lines in the sequence of the first lines have the same width, and

[0012] - at least one embossed structure on the background layer, the embossed structure comprising equidistant first geometric shapes providing a latent image made by embossing the first geometric shapes of the embossed structure at an offset relative to the sequence of first lines of the background layer.

[0013] In turn, the publication EP4331858 discloses an optical anti-counterfeiting security element which has a diffuse reflection area (2); the diffuse reflection area is capable of reflecting incident light within at least a predetermined viewing angle Qv; the diffuse reflection area comprises a plurality of reflective facets comprising modified facets that are globally or locally modified, and unmodified reflective facets, the modified and unmodified reflective facets having different reflection characteristics, the modified reflective facets corresponding to a pattern area. When the diffuse reflection area is illuminated by incident light, the modified reflective facets collectively represent a pattern in the form of a variable security feature, and the unmodified reflective facets collectively represent a background area for that variable feature. Such an anti-counterfeiting optical element is not only easy to manufacture, but also provides easy implementation of variable features such as color and / or light-dark contrast.

[0014] Patent literature also provides information on methods for the manufacture of computer- designed security elements with an angular effect.

[0015] Namely, the patent specification WO2014 / 124374 describes an algorithm for use in a method for the manufacture of a security element with an angular effect, wherein the security element is characterized by multi -tonality in a full gray scale. The solution disclosed in the publication concerns providing an angular effect by dividing an image into a multi-cell grid, in which each cell contains an arrangement of graphic elements, a sub-image, modified in accordance with the parameters of the initial image. According to the disclosure, the physical area providing the angular effect is divided into a grid of sub-areas (cells) providing the angular effect, wherein each sub-area providing the angular effect (each cell) is designed such that the obtained angular effect corresponds to a corresponding tone in the gray scale, and the grid of sub-areas providing the angular effect provides a latent image in a full gray scale. In this solution, the substrate bearing the angular effect marking must be rotated by 180 degrees to reveal the full image, which presents a significant drawback in everyday use by consumers, particularly the average user with no experience in verifying this type of security features. Furthermore, in one embodiment, described in said patent publication, the grid cell contains only one graphic element, which in turn does not ensure the desired quality of the angular effect obtained. Furthermore, the patent literature also describes methods for enhancing the quality of security features against counterfeiting and providing an additional visual effect by overprinting or embossing optical structures, preferably on previously applied inks or light-reflecting layers, particularly metallic foils. For example, when using a gravure printing technique to manufacture a security element, security elements are produced in which the background is embossed, either with or without added ink, in accordance with a first raster of parallel lines, and the hidden security element forms a second raster of parallel lines arranged at an angle, preferably at the right angle, relative to the first raster lines, thus providing a hidden image that is difficult to detect when viewing the document secured by such a security element at the right angle to the substrate, and detectable when viewed at an angle other than a right angle.

[0016] The prior art also includes secured documents in which the security feature is in the form of an embossing, which is manufactured, for example, by contacting a matrix with a substrate. The substrate is coated with a deformable, light-reflective layer; preferably, the substrate is or includes a metallic foil as an outer layer.

[0017] Embossing involves pressing down the matrix onto the substrate. As a result of the pressure of the matrix, the outer layer covering the substrate, such as a metallic foil, is integrated in the substrate, and the shape of the matrix is reproduced on its surface, creating the document’s security element. Known security elements manufactured in this way include extremely complex images containing various patterns or motifs, particularly in the form of letters, numbers, or images. However, this type of security feature lacks typical kinematic characteristics.

[0018] A solution with such features is disclosed, for example, in the European patent EP1716004, which describes a method of printing a steel-engraved structure on metallic foil, consisting of lines arranged at different angles to each other. However, the optical effect of movement achieved in this way does not provide the desired security quality because the print obscures the glossy foil, and the method of achieving such security is extremely demanding in terms of production.

[0019] In turn, another European patent EP0433330 discloses a method for the manufacture of a security device on a substrate, comprising embossing a metal foil with a steel-engraved structure containing a first security element with an angular effect in the form of a transient image, and the secured document resulting therefrom. In a preferred embodiment, the unembossed portions of the substrate are overprinted using a gravure printing method. Although the resulting images are visible when the data carrier substrate is tilted perpendicularly to the substrate, such a solution, similar to those discussed above, lacks the effect of movement or depth.

[0020] Another European patent EP2941356 discloses a security element for secured documents comprising

[0021] - a substrate with a surface,

[0022] - at least one first, second, third and fourth pattern with first, second, third and fourth pattern angles, wherein each pattern comprises an embossed structure of the substrate, the embossed structures being shaped such that upon vertical viewing of the surface of the structure, all four patterns are visible, and upon oblique viewing of the surface of the substrate in at least one predetermined viewing direction, at least a part of one of the patterns is obscured by at least one part of at least one of the embossed structures such that upon alternating perpendicular and angled viewing of the surface of the substrate, an optically latent image is revealed, and wherein

[0023] - the first protective information is formed as a local distribution of the first and second pattern, which comprises a first partial region and a second partial region of the substrate, wherein the first pattern is disposed in at least a part of the first partial region and the second pattern is disposed in at least a part of the second partial region,

[0024] - and the second protective information is formed as a local arrangement of the third and fourth pattern, which comprises a third partial region and a fourth partial region of the substrate, wherein the third pattern is located in at least part of the third partial region and the fourth pattern is located in at least part of the fourth partial region,

[0025] - and the first protective information and the second protective information are located in an at least partially overlapping manner, and which security element additionally includes

[0026] - a first cell grid, wherein the first pattern and the second pattern are located exclusively in the first cell grid, and

[0027] - a second cell grid, wherein the third pattern and the fourth pattern are located exclusively in the second cell grid, and the first cell grid and the second cell grid are located on the substrate side by side in a non-overlapping manner, and the first cell grid and the second cell grid are located on the substrate in a first and second direction parallel to the substrate on at least one portion of the substrate, alternating with each other, wherein at least the first cell grid and the second cell grid each comprise first cell grid types and second cell grid types, wherein the first cell grid types are shaped so as to surround the second cell grid types, and wherein for each pair of the first and second cell grids, the pair comprising the second cell grid type and the first cell grid type surrounds the second cell grid type, or

[0028] * the first pattern and the second pattern are located exclusively in the first cell grid type, and the third pattern and the fourth pattern are located exclusively in the second cell grid type, or

[0029] * the first pattern and the second pattern are located only in the second cell grid type, and the third pattern and the fourth pattern are located only in the first cell grid type.

[0030] A similar security feature was also disclosed in the description of the Polish utility model PL072267. This publication discloses a secured document containing linear structures that provide a movement and multi -tonality effect. These structures are embossed on metallic foil using a steel-engraving process, forming an image composed of lines that are positioned at multiple angles to each other. However, the color range achieved using the solution proposed as used herein is extremely limited due to the production limitations of the matrix. Consequently, this solution does not provide the desired quality, repeatability of the obtained effect, or high resolution, while maintaining the ease of obtaining such protection, which is desirable for the production of secured documents on an industrial scale.

[0031] While the structure of the security element does provide a visual effect similar to holography, where depending on the viewing angle of the secured document, some information becomes visible while other information is still invisible to the observer, it is still unsatisfactory. As disclosed in the PL072267 specification, it is not possible to obtain complex images that convey the effect of movement. The object of the present invention is therefore to develop a security element for a secured document that is more visually appealing and easier to use by the end user, while maintaining good resolution, and which is economical and efficient to manufacture.

[0032] GIST OF THE INVENTION

[0033] The present invention provides a secured document 100 comprising:

[0034] - a substrate 101, covered in at least two areas with an additional layer, wherein

[0035] - in a first area 106, the substrate 101 is covered with an effect layer 104 made of a material susceptible to deformation under the influence of an external pressure force, and reflecting light, having a high light reflectance coefficient, and

[0036] - in a second area 107, the substrate is covered with a print layer 103 of a colorful material constituting the covering medium, and wherein

[0037] - in the first area 106 there is a first security element 102 and in the second area 107 there is a second security element 105, the first security element 102 being an optically variable structure 108 embossed by the gravure printing method, and the second security element 105 being a printed marking made by the gravure printing method, and wherein the optically variable structure comprises at least one latent initial image, and the optically variable structure is formed by an arrangement of cells 401, each of which comprises an embossed geometric pattern rotated by a predetermined angle relative to a predetermined direction and / or reference point, which geometric pattern, when illuminated with light at a predetermined angle, reflects a corresponding grayscale tone representing a portion of the latent image.

[0038] Preferably, the arrangement of cells 401 is a grid 400 of square cells 401, wherein a single cell 401 corresponds to a single point of the image hidden in the first security element 102, wherein in each cell 401 there is a sub-image 403 formed by an arrangement of convex, embossed lines 402 parallel to each other with a defined height h in relation to the surface of the effect layer 104 located between the lines 402, wherein the sub-image 403 formed from the arrangement of lines 402 is rotated by an angle of rotation in relation to a selected axis of the first security element 102, identical for all cells, defined in the plane of the substrate 101, which angle of rotation is constant within each of the cells 401 of the grid 400 and this angle of rotation is in the range from 1 to 180°, and the number of lines 402 in each of the cells 401 of the grid 400 is equal to or greater than three.

[0039] According to a more preferred embodiment, the maximum distance measured between the most distant points of each of the cells 401 does not exceed 1 mm, preferably is less than 0.7 mm, more preferably is less than 0.5 mm and most preferably is less than 0.1 mm.

[0040] The preferred covering medium for the colorful material of the second print layer 103 is a high viscosity medium.

[0041] Preferably, the secured document 100 is a valuable document, preferably a banknote, ticket, collector’s voucher, gift voucher or stamp, more preferably a banknote.

[0042] Preferably, the height h of the raised, embossed lines 402 is less than or equal to 0.1 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.03. Also preferably, the thickness D of the raised, embossed lines 402 is less than or equal to 0.3 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.03. In particularly preferred embodiments, the height h and the thickness D of the tactile, raised, embossed lines 402 are the same, h = D.

[0043] Preferably, the material susceptible to deformation under the influence of an external pressure force and having high light reflectance coefficient of the effect layer 104 is selected from the group consisting of a metallic foil, holographic foil, prismatic foil or metallic or optically variable ink applied by offset, letterpress, screen-printing, rotogravure or flexographic methods.

[0044] The preferred colorful material of the covering medium of the print layer 103 is selected from the group consisting of writing inks, drawing inks and security inks.

[0045] Also preferably the substrate 101 is made of a material selected from the group consisting of paper, plastic, in particular polypropylene (PP) plastic or composites.

[0046] According to a preferred embodiment of the invention, the first security element 102 and the second security element 105 are applied to the substrate in one continuous manufacturing process.

[0047] Preferably, the first substrate region 106 and the second substrate region 107 are arranged on the substrate 101 such that the first security element 102 and the second security element 105 form an integrated security pattern 109 globally perceptible to the naked eye as a single security feature.

[0048] According to preferred embodiments of the invention the substrate 101 additionally comprises other security elements integrated in the structure of the substrate 101 material, preferably selected from watermarks, security threads, security fibers.

[0049] Preferably, the first effect layer 104 has a surface area smaller than the structure of the embossed first security element 102. In another alternative embodiment, the first effect layer 104 has a surface area larger than the embossed structure of the first security element 102.

[0050] In preferred embodiments, the document according to the invention additionally comprises security elements in the form of relief and / or raster security features, microtexts, guilloches, iris transitions, applied to the substrate 101 outside the first substrate region 106 and outside the second substrate region 107.

[0051] Preferably, the secured document comprises at least one additional third region 110, on which the substrate 101 is covered with an effect layer 104 of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflectance coefficient, and a second print layer 103 of a colorful material constituting a covering medium, on which a third optical security feature in the form of a color tactile marking made by gravure printing technique is provided.

[0052] The present invention also provides a process for the manufacture of a matrix 502 for production of the secured document 100 according to the invention, the process comprising the steps of: a) selecting a color source image corresponding to the marking to be applied, preferably an image, motif, pattern or character, for the first security element 102; b) designing a color initial image 601 for the first security element 102, in which step, after processing the source image for the first security element 102, preferably by means of a computer configured to designing graphic images, to generate a graphic image that should ultimately be perceived by the naked eye on the first substrate region 106 of the secured document, a set of input data is determined which define the desired marking of the first security element 102 as a grid 400 of single-color cells 401, which cells 401 are assigned a color averaged over the area of a single cell 401 as defined in the RGB scale; c) converting, by means of a computer configured to perform such conversion, the indicated input data corresponding to the initial image into a graphic file describing the color initial image as a grayscale image; d) assigning to the specific color of each cell 401 expressed in a gray scale a specific degree of inclination of the parallel lines, said degree of inclination being in the range from 1 to 180°, and the extreme values of the degree of inclination corresponding to the extreme colors, in particular the colors white and black, respectively; e) selecting a source image for the second security element 105; f) designing a color initial image 601 for the second security element 105, in which step, after processing the source image for the second security element 105, preferably by means of a computer configured to designing graphic images, to generate a graphic image that should ultimately be perceived by the naked eye on the second substrate region 107 of the secured document 100, a set of input data is determined which define the desired image of the second security element 105 as the graphic design for printing; g) combining the set of input data defining the image of the first security element 102 and of the second security element 105 into one set of input data defining the security feature of the secured document 100; h) forming an gravure printing matrix 502, preferably by etching, laser engraving or mechanically engraving the plate in accordance with the set of input data defining the security feature of the secured document 100, by etching the surface of the matrix 502 under the control of a computer configured therefor to generate in the first region 106 an arrangement of cells 401 of the grid 400, said cells 401 comprising a set of at least three mutually parallel linear recesses, and in the second region 107, imaging the marking corresponding to the second security element 105 to generate recesses in the matrix 502 defining the contours of the applied marking; i) curing the matrix 502.

[0053] In preferred embodiments, step g) of curing the matrix 502 includes the manufacture of target production printing plates by electroplating methods.

[0054] In other, alternative preferred embodiments of the process, step i) of curing the matrix 502 comprises coating the matrix 502 with a material having enhanced mechanical parameters. The present invention also provides a process for the manufacture of the secured document according to the invention using the matrix 502 obtained by the process according to the invention, the process for the manufacture of the secured document comprising the steps of: a) covering (5.1-5.3) the first region 106 of the substrate 101 with the effect layer 104 made of a material susceptible to deformation under the influence of an external pressure force, and reflecting light, having a high light reflectance coefficient; b) coating (5.4) all the recesses on the second region of the matrix 502 with a color coating material; c) pressing down (5.5 -5.6) the matrix 502 with

[0055] - deforming under pressure force the light-reflecting material with a high light reflectance coefficient on the first region 106 of the substrate 101 and reproducing recesses in the matrix 502 on the first region 106 of the substrate 101 in the material of the effect layer 104 deformable under an external pressure force, and forming a marking corresponding to the first security element 102, and

[0056] - transferring the color coating material from the recesses of the matrix 502 onto the substrate 101 in the second region 107 of the substrate 101 with reproducing the marking corresponding to the second security element 105.

[0057] Preferably, covering (5.1-5.3) the first region 106 of the substrate 101 with the effect layer (104) made of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflection coefficient, is carried out by means of the offset printing, letterpress printing, screen printing, flexographic printing, hot- stamping, cold-stamping technique, preferably by means of the hot-stamping technique.

[0058] Due to the fact that the document has two different types of security features in the form of the first and the second security elements, both of which are made using the same gravure printing technique, its production requires much less work than in the case of security features known from the prior art, and is less expensive, while the document itself is more difficult to forge.

[0059] Because the matrix image cells, i.e., the cells in the effect layer area, are designed to reflect grayscale tones that change depending on the lighting angle, the effect of movement of the reproduced pixels is created when the secure document is rotated, which makes the security element of the invention more visually appealing. Furthermore, the motion effect provided by the security element allows the end user to perceive this type of security feature even with minimal movement of the secured document, and allows to quickly and easily determine whether the security feature is behaving properly, and consequently whether the secured document is authentic or not.

[0060] Moreover, due to the fact that the matrix image cell, i.e. the cell of the effect layer area, contains an embossed geometric pattern in the form of at least 3 parallel lines, a very good resolution of the hidden image is ensured.

[0061] Another advantage of the secured document according to the invention is that the graphic image of the matrix image is generated by an automated computer algorithm, which makes its design very time-efficient, and the process is highly economical. Subimages are automatically generated within the matrix image, allowing for the manipulation of their resolution, including, in particular, significant increase thereof, which was not possible when creating similar security features using prior art methods.

[0062] Due to the proposed grid structure of areas (cells) providing the angular effect based on a suitably designed geometric pattern (arrangement of embossed elements), it is possible to obtain a full range of colors or tones while maintaining high production output and economic efficiency during the production of such a security element and a secured document provided with it. This enables appearance / disappearance of certain image components, particularly the latent image.

[0063] Moreover, the proposed process allows for the introduction of more than one arrangement of embossed elements into the grid structure of the areas (cells), which elements are visible from different viewing angles of the secured document bearing such a security feature. This also leads to obtaining the illusion of movement in the image created by specific geometric patterns.

[0064] In particular, advantageously with maximum optimization of the production of the security element, it was possible to deliver a security element that is difficult to copy, visually attractive and includes various markings, in particular images, patterns, motifs or signs.

[0065] Due to the fact that the security feature includes two integrated security elements, arranged so that they interact visually and functionally, the level of document security has been significantly increased.

[0066] BRIEF DESCRIPTION OF THE DRAWING The subject-mater of the present invention is shown in various embodiments illustrated in the drawing, in which:

[0067] Fig. 1 shows a secured document 100 with an embossed optical element 108 and a further security element according to another embodiment.

[0068] Fig. 2 shows a schematic process for the manufacture of a secured document 100 with security elements, comprising the following steps: 1 - providing a substrate 101, 2 - providing a first effect layer 104, 3 - obtaining security elements 102 and 105 by means of the gravure printing technique. In Fig. 2, consecutive steps of the process are marked with the letters a), b) and c), respectively, while the directions of the arrows illustrate overlapping of subsequent layers of the secured document.

[0069] Fig. 3 shows a schematic and simplified visualization of the graphics of the effect layer 104 of the embossed optical element 108 in an enlarged view, showing the structure of the areas of lines 402, which function as a secured element in the secured document 100 according to another embodiment.

[0070] Fig. 4 shows the visualization of the cell 401 of the grid 400 of subimages, which are straight lines 402. 401 - a grid cell with lines, 402 marked cell lines.

[0071] Fig. 5 schematically shows the operating principle of the security device according to the present invention.

[0072] Fig. 6 shows a schematic side view of a process for the manufacture a document 100 using a matrix 502, according to one embodiment, wherein step 5.1 is a step of providing a substrate 101, 5.2 - of applying an effect layer 104 by hot-stamping technique, 5.3 - of obtaining the substrate 101 with the effect layer 104, 5.4 - 5.5 - of gravure printing comprising manufacturing of an embossed optical element 108, 5.6 - of obtaining the document 100 with the security element.

[0073] Fig. 7 shows a schematic side view of a process for the manufacture of a document 100 using a matrix 502, according to a further embodiment, in which embossing takes place in the area of an effect layer 104, and printing takes place in the area of a print layer 103, wherein step 5.1 is a step of providing a substrate 101, 5.2 - of applying the effect layer 104 by hot- stamping technique, 5.3 - of obtaining a substrate 101 with the effect layer 104, 5.4, 5.5 - of gravure printing comprising manufacturing of an embossed optical element 108 and printing in the area of the print layer 103, 5.6 - obtaining the document 100 with the security elements. Fig. 8 shows an initial image and a generated visualization of a grid 400 of sub-images for a security element according to one embodiment.

[0074] Fig. 9 shows a manufactured embossed optical element 108 according to one embodiment.

[0075] Fig. 10 shows a secured document 100 according to an exemplary embodiment.

[0076] DETAILED DESCRIPTION OF THE INVENTION

[0077] As used herein, the term „document” includes any identification document (such as a passport) or a valuable document, preferably a valuable document. Particularly preferred documents of value in accordance with the present invention are paper documents, especially paper documents with security features such as, for example, banknotes, securities such as bonds or other certificates of rights, banderoles, tickets, vouchers, especially collector’s vouchers, stamps and the like.

[0078] In accordance with the present invention, „optically variable element” refers to security features that display different images, in particular data or other information, depending on the viewing angle or lighting conditions. The effect of optical variability is achieved, among other things, by rotating and / or tilting the document bearing the security feature.

[0079] As used herein, the term „initial image”, „image to be reproduced”, „image to be reproduced movably”, „hidden image”, „movable hidden image” means an image (set of images) composed of an array of pixels, or is at least one selected fragment (segment) of the image after segmentation, which is to be visible statically or in motion when the angle of incidence of light on the optically variable element containing it changes.

[0080] As used herein, the term „matrix image” means a manually designed or computer-designed image that reflects virtually designed embossing geometry.

[0081] As used herein, the terms „grid” and „network” are used interchangeably and denote an arrangement of cells in a matrix image, i.e., an image based on which the corresponding embossing matrix is shaped, wherein each cell has an area of the same or different shape in relation to neighboring cells, and the arrangement of cells in the matrix image reproduces the image hidden in the optically variable element. In the case where the matrix image reproduces a hidden image, understood as an array of pixels, each pixel of the hidden image corresponds to one cell in the matrix image, and the cell grid of the matrix image is then an “array” or “pseudo-array” of cells. As used herein, the terms “multi-shade” or “multi-tone” are used synonymously with a monochrome image. The disclosure herein uses latent images that, in addition to shades of gray, include shades of any color or colors; “tone” and “shade” are used interchangeably. A tone level or tonal value refers to the level of lightness, darkness, and grayness.

[0082] As used herein, the term “cell” defines a sub-region of the matrix plane and, respectively, the substrate of the secured document, wherein, in the case of the substrate of the secured document, the substrate is modified in this sub-region so that, by reflecting light, it gives the impression of a specific grayscale tone depending on the angle of incidence of the light. Each cell has a predefined shape, selected for example from a square, rectangle, circle, triangle, or other polygon, and a size, and the substrate modification is an embossed pattern designed so that its geometry reflects light differently for different angles of incidence of light.

[0083] As used herein, the term “cell pattern”, “sub-image” means an appropriately designed embossing geometry that fits within the area of a single cell, wherein the designed geometry, the designed geometric pattern, is formed of at least two geometric elements, for example lines, preferably parallel to each other, preferably straight lines.

[0084] According to the present description, the term “line” should be understood as any line / curve on a plane that does not have to be straight, for example a broken line, wherein the line is preferably a straight line, such as a graphic symbol connecting two points on the plane by the shortest path.

[0085] In accordance with the present description, whenever reference is made to an “image” or “pattern”, “motif’ or “mark”, this should be understood as a generally visually legible marking, often conveying specific information, in particular a marking on a specific background.

[0086] The present invention enables encoding, in an optically variable element, an image with more than two states, i.e., the color black (transmittance 0) and the color white (transmittance 100%). A latent image containing multi-shade image elements is visually more attractive compared to latent images with only two states.

[0087] As shown in Fig. 1, in one embodiment, a secured document 100 according to the invention includes at least one security element.

[0088] Therefore, in accordance with an embodiment of the invention, a secured document 100 comprises a substrate 101 partially coated with an additional layer, at least in two, preferably non-overlapping, and in particular non-overlapping, areas. On at least a first substrate region 106, an effect layer 104 is applied, modifying the substrate 101, made of a material that is deformable under the influence of an external pressure force and that reflects light and has a high light reflectance coefficient. On at least a second substrate region 107, a printable layer 103 is applied which modifies the substrate 101, made of a colorful material constituting a high-viscosity covering medium.

[0089] Furthermore, on the first substrate region 106 a first security element 102 is provided, which is an embossed optically variable optical element 108. The optical element 108 is embossed by the gravure printing method and comprises an embossed structure in the form of an arrangement of cells 401, each of which contains an embossed pattern. The arrangement of cells 401, viewed from the top (perpendicular to the substrate 101), forms a matrix image. In one embodiment, the cells 401 may be in contact with each other. The shape of a single cell 401 may be, for example, any regular geometric figure, preferably a circle or a polygon, in particular a regular polygon, more preferably a parallelogram, and, most preferably, a square. A single cell 401 corresponds to a single point in the latent (initial) image or a single segment in the latent (initial) image, understood as optically perceived spatial information, and which is to be reproduced in the first security element 102.

[0090] Each cell defines a spatially modified sub-region of the substrate 101, according to a certain geometric pattern, covered with an effect layer 104, containing a sub-image 403 in the form of an embossed pattern. Geometric embossing patterns, visible to the naked eye as sub-images 403, are created, for example, by convex line 402 arrangements embossed in the effect layer 104, parallel to each other in one cell, which in fact constitute embossing ridges with a specific height h relative to the surface of the substrate 101.

[0091] It should be understood that the contours of the cells 401 shown in the figures of the drawing are not embossed in the effect layer, i.e. they are not a part of the embossing matrix.

[0092] It should be understood that lines 402, shown as geometric elements of the geometric pattern contained in the cell on the matrix image, are not actually printed, but only graphically reflect the highest embossed areas (convexities).

[0093] The lines 402 in each of the cells 401, 400 are, for example, parallel to each other, and their angle of inclination with respect to the selected axis of the first security element 102, identical for all cells, defined in the plane of the substrate 101, is constant within each of the cells 401 of the grid 400 and varies in the range from 1 to 180°. A number of the lines 402 in each of the cells 401 of the grid 400 is equal to or greater than three. The maximum distance measured between the most distant points of each of the cells 401 does not exceed 1 mm, preferably is less than 0.7 mm, more preferably is less than 0.5 mm, and most preferably is less than 0.1 mm.

[0094] In one embodiment, the second region 107 may or may not include a second security feature 105, which is a visually perceptible, color, preferably multi-colored marking formed by the print layer 103. Both the first security feature 102 and the second security feature 105 are applied on the substrate 101 by printing using gravure printing techniques well known in the art, and in particular the steel-engraving technique.

[0095] In yet another embodiment of the present invention, a secured document 100 comprises at least one additional third region 110 having an effect layer 104 made of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflectance coefficient, and a print layer 103 of a reflective, high viscosity color overlay material, said third region 110 having a third optical security feature in the form of a tactile indicia made by color gravure printing technique.

[0096] In practical implementations of the present invention, a backing material layer 101 may be a substrate 101 made of various materials, for example, paper, plastic such as polypropylene (BOPP) and composites thereof, paper with added plastic fibers, or a paper-plastic composite, also known as a hybrid substrate.

[0097] In practical implementations of the present invention, the effect layer 104 may be made of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflectance coefficient, preferably a metallic foil, holographic foil, or prismatic foil. The effect layer 104 may also include a layer of optically variable pigments or other coating materials, such as, for example, a metallic coating, metallic paint, iridescent coating, glossy varnish, or optically variable paint.

[0098] The effect layer 104 may be applied onto the layer of the substrate material 101 by means of various techniques such as, for example, offset printing, letterset printing, typography printing, screen printing, flexographic printing, hot-stamping or cold-stamping techniques.

[0099] One of the features of the secured document is that the effect layer 104 is characterized by gloss (shines) when illuminated, for example with visible light, while the layer of the substrate material 101, when illuminated with the same light, is characterized by gloss to a degree different than the effect layer 104; in particular, if it is dull, it may have much lower gloss.

[0100] In embodiments of the present invention, the print layer 103 is a layer of colorful material constituting a covering medium. The covering medium is preferably selected from the group consisting of writing inks, drawing inks, and security paints. In one embodiment, the covering medium is a high viscosity covering medium.

[0101] In one embodiment of the present invention, the first security element 102 and the second security element 105 are applied to the substrate 101 in one continuous production process, in particular in one production step.

[0102] There is no known process for the manufacture of a secured document in the art, in which the first security element 102 and the second security element 105 can be obtained in one step. According to the invention, an integrated arrangement of at least two different security elements is thus provided.

[0103] In another embodiment of the present invention, the first substrate region 106 and the second substrate region 107 are arranged on the substrate 101 such that the first security element 102 and the second security element 105 form an integrated security pattern 109 globally perceptible to the unaided eye as a single, coherent security feature.

[0104] In accordance with the present invention, the term integrated” denotes a coherent and integral element. In particular, the term integrated security element” denotes a marking that creates a coherent security feature that is perceptible in a single act, preferably formed by at least two different security elements, each manufactured using a different technique. The term integrated security element” should also be understood here as being manufactured simultaneously, i.e., in a single production step.

[0105] In one embodiment of the present invention, the substrate 101 additionally also comprises other security elements integrated into the structure of the substrate material 101, preferably selected from watermarks, security threads, security fibers, filigrees, holographic stripes. Within the meaning of the present invention, and in accordance with the definition given above, the term integrated into the structure of the substrate” means an element incorporated into the substrate, being part of the substrate, preferably a paper substrate.

[0106] In another practical embodiment of the present invention, the substrate 101 additionally also comprises other security elements applied to the substrate 101, preferably by printing methods together with the first security element 102 and the second security element 105, or in another process, such as microtexts, guilloches, reliefs, iris transitions, special rasters, portraits.

[0107] Fig. 2 schematically shows a method for the manufacture of a secured document 100 with security elements, i.e. a first security element 102 and a second security element 105. Fig. 2 shows the following simplified steps: a) - providing a substrate 101, b) - providing a first effect layer 104, c) - making the second security element 105 and simultaneously making the first security element 102 by modifying the effect layer 104.

[0108] Fig. 3 schematically shows an image reproduced by an embossed optical element 108 being a first security element 102, wherein the image is reproduced by an arrangement (grid) of embossed geometric patterns forming a grid 400 of cells 401.

[0109] In one embodiment of the present invention, the first effect layer 104 has a surface area smaller than the area of the embossed structure of the first security element 102. In an alternative embodiment, the first effect layer 104 has a surface area larger than the area of the embossed structure of the first security element 102.

[0110] In another embodiment of the present invention, the secured document 100 additionally comprises security elements applied to the substrate 101 outside the first substrate region 106 and outside the second substrate region 107, such as microtexts, guilloche lines, relief images, optically variable inks, inks fluorescent under UV light, special rasters, etc.

[0111] As shown on the enlarged view in Fig. 4, each of the cells 401 comprises a sub-image 403, i.e. a geometric pattern physically represented by embossed geometric elements, for example in the form of embossed lines 402, the geometric patterns being designed to reproduce the corresponding grayscale tone of the selected pixel or segment of the initial image 601 for a given angle of light incidence.

[0112] Preferably, the grayscale tone is obtained by an appropriately designed rotation of the subimage (an arrangement of at least two geometric elements) by a given angle relative to a reference point, for example the center of a given cell 401. The rotation angle may be automatically determined by a computer-implemented algorithm, as will be described hereinbelow.

[0113] The graphic design of the first security element 102, and consequently the shape of the embossing matrix, is designed according to the invention by means of a computer. More specifically, in a first step, a so-called initial image 601 is provided, which is to be reproduced on the substrate 101 in the embossed optical element 108 by means of a suitable embossing matrix. Preferably, the initial image 601 is a photograph or any multi-colored image of a given size and any content, i.e. containing any motif.

[0114] The motifs contained in initial image 601 include both realistic and abstract motifs, including linear motifs in particular. Examples of realistic motifs include portraits, landscape motifs, plant motifs, and animal motifs. Images of coats of arms, buildings, and flags may also be realistic motifs. Abstract motifs encompass all other graphic forms of markings, including, in particular, those consisting of specific patterns, signs, or codes. Other specific examples of abstract motifs include text or individual letters or numbers.

[0115] According to the present invention, it is possible that in normal lighting conditions and without the use of any reading elements or additional devices, only parts (segments) of the reproduced primary image 601 are visible in the first security element 102, such as, for example, parts of a pattern, such as, for example, line patterns, text, letters or numbers, which become fully visible only after being read by the corresponding reading element.

[0116] According to one embodiment, in a next step, the initial image 601 in the form of a pixel array, shown in Fig. 8, if it is a color image, is converted to the gray scale using the algorithm of the invention. However, this step is an optional step if the initial image 601 is already a grayscale image.

[0117] A person skilled in the art will appreciate that a grayscale image is an image in which the share of each of RN, GN, BN components is the same, i.e. fulfilling the 1 : 1 : 1 ratio. Generating a gray shade image (grayscale image) from a color image comes down to transforming the initial image 601 in such a way as to obtain, for each pixel of the image, the same share of each of these components, corresponding to the degree of brightness of the pixel.

[0118] In accordance with one exemplary embodiment of the present invention, the primary image 601 is converted from full color to grayscale using methods known in the art. For example:

[0119] RN = 0.33*Rs + 0.33*Bs + 0.33*Gs,

[0120] GN = 0.33*Rs + 0.33*Bs + 0.33*Gs,

[0121] BN = 0.33*Rs + 0.33*Bs + 0.33*Gs, where RN, GN and BN are the color parameters (red, green, blue) of the pixel of the new initial image 601’ (grayscale) located at position X, Y, while Rs Gs Bs are the color parameters of the pixel at position X, Y of the old initial image 601 (multi-colored).

[0122] In another exemplary embodiment of the invention, algorithms are used that vary the multiplication factor of each of the color parameters, to increase the contrast and overall quality of the new initial image 601’ after conversion.

[0123] This is because the human eye is more sensitive to the green color and least sensitive to the blue color. An example of converting a color image to the gray scale is described by the following formula:

[0124] Next, an optional pixelization step is performed. Image pixels are grouped into arrays with user-defined dimensions (e.g., 5 x 5, or any other dimensions). This step reduces the resolution of the primary image 601 to the resolution available for the given embossing technique.

[0125] Then, the algorithm calculates the average color for the given array. Each pixel has a given red, green, and blue color value. Preferably, this value is between 1 and 256 or 0 and 255. In grayscale, all three colors have the same value at a given pixel, so to simplify the calculations, the following formula is used:

[0126] Average Color = (Red 1 + Red 2.... Red n) / n also presented as:

[0127] Average brightness of the array = (Brightness 1 + Brightness 2 ... Brightness n) / n

[0128] Since each RGB color component is identical, this value is also referred to as the color brightness. In an alternative embodiment, it is also possible to first perform the pixelization process and only then convert the multicolor image 601 to a grayscale image 601’.

[0129] In the next step, the primary image 601 is processed into a matrix image, which is placed on the matrix of the device for the manufacture of a secured document. This step involves first selecting at least two geometric elements and selecting their relative arrangement, which, while forming the pattern of the future cell 401 (of a matrix and later of a substrate of a secured document), should represent a pixel of the grayscale image 601’. For example, the geometric element can be a line, and the geometric pattern may be an arrangement of lines, preferably at least two lines, preferably parallel to each other. The geometric pattern is selected so that, at for least one predetermined angle of the incident light, its fragment reflects the incident light completely.

[0130] Then, for each pixel of the initial image 601, the algorithm calculates the rotation angle of the geometric pattern (sub-image 403) relative to the selected reference point, preferably relative to the geometric center of a cell 401 depending on the type of the selected geometric pattern. In the case of the arrangement of lines, the algorithm calculates the line rotation angle based on the calculated average color assigned to the linear structure. The calculated line rotation angle is directly proportional to the color, e.g.: assuming that the line rotation range is to be from 0 to 90 degrees for an array brightness scale defined in the range from 0 to 255, the following formula can be applied: sub-image rotation angle in the array = average brightness of array pixels * 90 degrees / 256

[0131] It is possible to assign any limiting values of rotation angles for the limiting tonal values of the grayscale image, i.e. for the white and black colors, for example: white color -45 degrees, black color +45 degrees, or white color = 90 degrees, black color = 0 degrees

[0132] Then, the matrix image is created by mapping the initial image onto the corresponding arrangement of cells 401 in the matrix image. If the initial image 601 is not segmented and is mapped as a matrix of pixels, the number of cells 401 in the matrix image cannot be smaller than the number of pixels in the initial image. The arrangement of cells 401 is selected depending on the type of initial image and the transformation operations performed on it, including segmentation. As a rule, each cell 401’ is filled with a sub-image 403 (geometric pattern) predicted by the algorithm for a given fragment of the initial image 601. In the case of a square-shaped cell, the algorithm according to the invention assigns to a cell 401 a geometric pattern consisting of an arrangement of parallel lines rotated relative to the center of the cell by a rotation angle calculated by the algorithm. The number of lines 402 in a given cell 401 of a grid 400 is at least 3, and the maximum number of lines 402 depends on the line thickness, generally the area occupied by a geometric element in a given dimension, and consequently the maximum number of lines 402 depends on the distance between geometric elements in the geometric pattern - so they do not overlap. In the preferred embodiment, the line thickness and the number of lines are selected so that the lines 402 do not overlap each other within the area of a single cell 401. Geometric patterns are designed so that their geometric elements do not extend beyond the area of the cell 401, and especially beyond the area of the virtual cell 401’ into which the matrix image is virtually divided when it is necessary to perform mapping of the initial image to the matrix image in a 1 : 1 ratio. In the case of a line arrangement, lines 402 do not extend beyond the area of their cell 401 of the grid 400.

[0133] A person skilled in the art will appreciate that the mapping of the initial image need not be performed in the 1 : 1 ratio. Then it is possible to use cells 401, the shape of which does not have to be a geometric figure that can be inscribed in the virtual cell 401’ of the matrix image array. In such a case, the cell 401 of the matrix image array may have the shape of a triangle or other polygon, and the matrix image may be supplemented at the edges with appropriate edge cells, which do not have to, but may have a function of mapping a specific edge pixel of the initial image, so as to digitally obtain an array of pixels of the matrix image.

[0134] In the case of using square-shaped cells 401 inscribed within a virtual cell 401 of the matrix image grid so as to overlap it entirely, an essential feature of all embodiments of the present invention is that each line 402 within a single cell 401 of the matrix image array 400 has a width of no more than 100 micrometers. For example, the lines 402 may have a width of from 10 to 100 micrometers, and more preferably, the lines 402 may have a width of from 40 to 60 micrometers, most preferably about 50 micrometers. Furthermore, a distance D between two lines 402 within one cell 401 of the matrix image array 400 is no more than 100 micrometers. The lines 402 of the cells 401 of the array 400 are preferably straight lines, although in other preferred embodiments, the lines may be curved lines at selected segments, for example, the lines may have a wavy shape.

[0135] Fig. 5 a-c schematically illustrate the operating principle of the security feature according to the present invention. The consecutive Figs 5 a-c show the already embossed structure of the first security element 102, which is illuminated by a light beam incident each time from a different angle. Each embossed line 402, due to being formed in the effect layer 104, has the property of reflecting the incident light, wherein the dimensions of the embossed lines 402 and their mutual shaping ensure that, after illuminating the secured document, the embossed lines 402, or line segments that are formed substantially perpendicular to the direction of the incident light 701, are visible to the observer 702. Depending on the direction of the incident light 701, specific embossed lines 402 of a given cell 401 of the array 400, schematically indicated by a bold line, are visible to the observer 702. On the other hand, the lines of the remaining cells 401 of the array 400 are not visible to the observer 702.

[0136] In the case of a smooth change in the direction of the incident light 701, for example when the observer 702 changes the angle of inclination of the secured document 100 with respect to the light source 701, a smooth change in the embossed lines 402 visible to the observer 702 is obtained, which creates the impression of a change in the content of the perceived image (disappearance of its selected components in certain places and reappearance of its other components in other places at the same time).

[0137] Furthermore, as mentioned before, in one embodiment of the present invention, the cells 401 of the array 400 may be spaced apart (not shown). For example, one of the cells 401 of the array 400 may be spaced apart from the adjacent cells 401 of the array 400. This occurs when the cell 401, which by definition is filled with a geometric embossed pattern (sub-image 403), is adjacent to a sub-region of the effect layer that is not modified and constitutes a background. In such a case, for example, the cells 401 of the array 400 may appear to be separated, for example, by a continuous line, which will constitute the non-embossed region of the effect layer 104. In another embodiment of the present invention, the given cell 401 of the array 400 may be tangent to one or more adjacent cells 401 of the array 400.

[0138] In other embodiments of the invention, the cells 401 form a grid structure 400 without the presence of spaces between the cells 401, including so-called tessellation,” and in particular form an array 400, e.g., when a cell 401 of the grid 400 is a square or rectangle. In other embodiments, a cell 401 may be a parallelogram or a polygon, in particular a regular polygon such as, for example, a triangle, a pentagon, or a hexagon. In alternative embodiments, cells 401 form a grid structure 400 in which the cells meet at a single point, e.g., when a cell 401 of the grid 400 is a circle or an ellipse, and a complementary shaped area is formed between them, which constitutes a background and is the unmodified area of the effect layer 104.

[0139] According to the invention, the effect layer 104 on which the cells 401 are defined can cover an area that can have any shape. In other words, the shape of the first security element 102 is independent of the shape of the area on which the effect layer 104 is located. This means that the area of the effect layer can be larger than the area of the designed embossing matrix.

[0140] The cells 401 with embossed lines 402 may also have any other shapes that do not form a more or less regular array type arrangement, but have the form of an arrangement of larger segments, for example parallel stripes, hoops, graphic symbols, letters, numbers, and / or repeating patterns such as wallpaper patterns.

[0141] In one embodiment of the invention, the size of one cell 401 in any direction is less than 1 mm, preferably 0.1 mm.

[0142] In one embodiment of the invention, the thickness of the line D forming the sub-image 403 of a given cell 401 is equal to or less than 0.3 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.03 mm.

[0143] In one embodiment, the height of the line h, which is the depth of the engraving on the printing form (embossing matrix), is equal to or less than 0.1 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.03 mm.

[0144] According to the invention, the number of geometric elements 402, in particular lines 402, in a given cell 401 is 3 or more. In the case of an arrangement of three parallel lines in one cell 401, the line thickness is preferably 0.025 mm. In the case of an arrangement of four parallel lines in one cell 401, the line thickness is preferably 0.02 mm.

[0145] In one embodiment, the height h of the raised embossings is perceptible by touch (tactile) and is less than or equal to 0.1 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.025.

[0146] In other embodiments of the present invention, the thickness D of the tactile, raised, embossed lines 402 of the secured document 100 is less than or equal to 0.3 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.03 mm. In yet another embodiment of the present invention, the height h and the thickness D of the tactile, raised, embossed lines 402 of the secured document 100 are the same, i.e. h=D.

[0147] The embossed lines 402 of the sub-image 403 of a given grid cell for each grid cell 401 of the grid 400 may be made in the first effect layer 104 using various techniques, including, for example, a steel-engraving process. Figures 6 and 7 illustrate processes for the manufacture of at least one security element of a document with a security feature 100 applied thereto.

[0148] Below, an exemplary process for the manufacture of a multi-layer document with the security features according to the invention is described, with reference to the specific embodiments thereof discussed hereinabove.

[0149] According to an exemplary embodiment of the present invention, shown in Fig. 6, in a first step 5.1-5.3, a first effect layer 104, preferably a metallic foil, more preferably a hot-stamping foil, is applied on the substrate 101 by means of a hot-stamping technique, i.e. printing using a hot-stamping foil constituting the effect layer 104 and convex matrices of a hot-stamping form 501 made of a heat-conducting material.

[0150] In one embodiment of the present invention, the hot-stamping foil may comprise a release layer, a lacquer layer, a vacuum-sprayed aluminum layer, and an adhesive layer. The convex matrix of the hot stamping form 501 is heated to approximately 100°C so that upon contact of the matrix with the foil, the adhesive layer is heated, which layer, together with a corresponding portion of the lacquer layer and the aluminum layer, remains on the hot- stamped surface.

[0151] In the next step 5.4, the structure of the effect layer 104 is placed on the steel-engraving form, which structure is the matrix 502, together with the other elements printed in this process.

[0152] Then, by the steel-engraving printing process, step 5.5, simultaneously with the above- mentioned printing, dry embossing of the optical element 108 is performed in place of the previously applied effect layer 104, thus obtaining a document with a security feature 100 applied, step 5.6.

[0153] According to another exemplary embodiment of the present invention (shown in Fig. 7), in step 5.4, the effect layer structure 104 is located on a steel-engraving form, which is a matrix 502, together with other elements printed in the process. This diagram also illustrates a part of the matrix 502 in which a print layer 103 is applied to the substrate by printing. In the recesses of the matrix 502, a coating agent is also shown, which modifies the substrate 101, consisting of a reflective, color, high-viscosity material, and which is transferred to the substrate 101 in the next step, 5.5, to form a second print layer 103.

[0154] Then, in the steel-engraving printing process, step 5.5, simultaneously with the above- mentioned printing, dry embossing of the optical element 108 is performed in the location of the previously applied effect layer 104, to provide a document with the security feature 100 applied, step 5.6.

[0155] According to another exemplary embodiment, the effect layer 104 may be applied by an offset, letterpress, or flexographic printing process, wherein an ink, e.g., a metallic ink, is locally applied through a printing plate and cylinders. In another exemplary embodiment, the effect layer 104 may be applied by a screen printing process, wherein an ink, e.g., an optically variable ink (OVI) or a metallic ink, is pressed with a doctor blade through a printing plate containing covered and uncovered meshes of the plate.

[0156] An exemplary process for the manufacture of a matrix 502 in accordance with the present invention is described below, comprising the steps of: a) providing a source image to be encoded in a first security element. The types of source images and possible motifs contained therein have been discussed above, b) designing (generating) a matrix image to be formed in the matrix. The step of the computer-aided design of the matrix image may comprise a variety of different steps depending on the type of initial image and the intended arrangement of cells 401, as described above. In the case where the initial image is an image in the form of a pixel array, and the intended arrangement of cells 401 is a square-shaped array of cells 401, and the embossed geometric pattern is to be an arrangement of parallel lines, this step comprises the following sub-steps: determining the tone of each pixel in the initial image 601 in a gray scale, determining, for each tone present in the grayscale image, a corresponding angle of rotation of the arrangement of parallel lines 402, assigning to each cell 401 a sub-image 403, i.e. the arrangement of parallel lines 402 rotated by a corresponding angle of rotation resulting from the grayscale tone of the pixel of the initial image associated with that cell 401. As described above, the degree of tilt is in the range from 1 to 180°, and the extreme values of the degree of tilt correspond to the respective extreme colors, in particular the colors white and black; e) providing a source image for the second security element 105; f) designing an initial color image for the second security element 105, in which step, after processing the source image for the second security element 105, preferably by means of a computer configured to design graphic images, to produce a graphic image to be ultimately perceived by the naked eye on the second region of the substrate 107 of the secured document 100, a set of input data defining a desired image of the second security element 105 as a graphic design for printing is determined; e) combining the set of input data defining a matrix image for the first security element 102 and a matrix image for the second security element 105 into a single set of input data defining a matrix image of an integrated security element; f) forming a steel- engraving printing matrix 502, preferably by laser engraving the plate in accordance with the set of input data defining the integrated security element.

[0157] Also described in more detail herein is an exemplary process for the manufacture of a secured document 100 using the matrix 502 obtained by the process as described above, comprising the steps of: a) applying, in step 5.1-5.3, on a first region 106 of a substrate a first effect layer 104 made of a material susceptible to deformation under the influence of an external pressure force, and reflecting light, having a high light reflectance coefficient, to modify said substrate 101; b) applying, step 5.4, a high-viscosity color overlay material into all the recesses on the second region of the matrix 502; c) pressing, step 5.5-5.6, the matrix 502 to deform under the pressure the light-reflecting material having a high light reflectance coefficient on the first region 106 of the substrate and to reproduce the recesses in the matrix 502 on the first region 106 of the substrate in the effect layer 104 material susceptible to deformation under the influence of an external pressure force, and to form a marking corresponding to the first security element 102, and to transfer the high viscosity overlay material from the recesses in the matrix 502 to the unmodified substrate in the second region 107 of the substrate to reproduce the marking corresponding to the second security element 105.

[0158] List of numeric references:

[0159] 100 - document with a security feature

[0160] 101 - substrate

[0161] 102 - first security element

[0162] 103 - second layer - a print layer

[0163] 104 - first layer - an effect layer

[0164] 105 - second security element

[0165] 106 - first substrate region

[0166] 107 - second substrate region

[0167] 108 - embossed optical element

[0168] 109 - security pattern 110 - third substrate region

[0169] 400 - grid

[0170] 401 - subimage grid cell

[0171] 402 - embossed lines 403 - subimage of a given grid cell

[0172] 501 - hot-stamping form

[0173] 502 - matrix (steel-engraving form)

[0174] 601 - initial image

[0175] 602 - visualization of a sub-image grid of an embossed optical element 701 - direction of incident light

[0176] 702 - observer

Claims

1. Claims1. A secured document (100) comprising: a substrate (101) covered in at least two areas with an additional layer, wherein- in the first region (106), the substrate (101) is covered with an effect layer (104) made of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflectance coefficient, and- in the second region (107), the substrate is covered with a print layer (103) of a colorful material constituting a covering medium, and wherein in the first region (106) there is a first security element (102) and in the second region (107) there is a second security element (105) wherein the first security element (102) is an optically variable structure (108) embossed by the gravure printing method, and the second security element (105) is a printed marking made by the gravure printing method, and wherein the optically variable structure comprises at least one latent initial image, and the optically variable structure is formed by an arrangement of cells (401), each cell comprising an embossed geometric pattern rotated by a predetermined angle relative to a predetermined direction and / or reference point, which geometric pattern, when illuminated with light at a predetermined angle, reflects a corresponding grayscale tone representing a portion of the latent image.

2. The secured document according to Claim 1, wherein the arrangement of cells (401) is a grid (400) of square cells (401), wherein a single cell (401) corresponds to a single point of the image hidden in the first security element (102), wherein in each cell (401) there is a sub-image (403) formed by an arrangement of convex, embossed lines (402) parallel to each other, of a specific height (h) in relation to the surface of the effect layer (104) located between the lines (402), wherein the sub-image (403) formed of the arrangement of lines(402) is rotated by an angle of rotation in relation to a selected, identical for all cells, axis of the first security element (102) defined in the plane of the substrate (101), which angle of rotation is constant within each single of the cells (401) of the grid (400), and the angle of rotation is in the range from 1 to 180°, and the number of lines (402) in each of the cells (401) of the grid (400) is equal to or greater than three.

3. The secured document according to claim 1 or 2, wherein the maximum distance measured between the most distant points of each cell (401) does not exceed 1 mm, preferably is less than 0.7 mm, more preferably is less than 0.5 mm and most preferably less than 0.1 mm.

4. The document according to claim 1 to 3, characterized in that the covering medium of the colorful material of the second print layer (103) is a high-viscosity medium.

5. The document according to claims 1 to 4, characterized in that the secured document (100) is a valuable document, preferably a banknote, a ticket, a collector’s voucher, a gift voucher or a stamp, more preferably a banknote.

6. The document according to claims 1 to 5, characterized in that the height (h) of the raised, embossed lines (402) is less than or equal to 0.1 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.03 mm.

7. The document according to any one of claims 1 to 6, characterized in that the thickness (D) of the raised, embossed lines (402) is less than or equal to 0.3 mm, preferably less than or equal to 0.05 mm, most preferably less than or equal to 0.03 mm.

8. The document according to any one of claims 1 to 7, characterized in that the height (h) and the thickness (D) of the tactile, raised, embossed lines (402) are the same (h=D).

9. The document according to any one of claims 1 to 8, characterized in that the susceptible to deformation under external pressure force and light-reflecting material having a high light reflectance coefficient of the effect layer (104) is selected from the group consisting of a metallic foil, a holographic foil, a prismatic foil or a metallic or optically variable ink applied by offset, letterpress, screen-printing, rotogravure or flexographic methods.

10. The document of any one of claims 1 to 9, characterized in that the colorful material of the print layer (103) is selected from the group consisting of writing inks, drawing inks and security paints.

11. The document according to any one of claims 1 to 9, characterized in that the substrate (101) is made of a material selected from the group consisting of paper, plastic, in particular polypropylene (PP) plastic, or composites.

12. The document according to any one of claims 1 to 11, characterized in that the first security element (102) and the second security element (105) are applied to the substrate in one continuous production process.

13. The document according to any one of claims 1 to 12, characterized in that the first region (106) of the substrate and the second region (107) of the substrate are arranged on the substrate (101) in such a way that the first security element (102) and the second security element (105) form an integrated security pattern (109) globally perceptible to the naked eye as a single security feature.

14. The document according to any one of claims 1 to 13, characterized in that the substrate (101) additionally comprises other security elements integrated in the structure of the substrate material (101), preferably selected from watermarks, security threads, security fibers.

15. The document according to any one of claims 1 to 14, characterized in that the first effect layer (104) has a surface area smaller than the structure of the embossed first security element (102).

16. The document according to any one of claims 1 to 14, characterized in that the first effect layer (104) has a surface area larger than the structure of the embossed first security element (102).

17. The document according to any one of claims 1 to 16, characterized in that the document additionally comprises security elements in the form of relief and / or raster security features, microtexts, guilloches, iris transitions applied on the substrate (101) outside the first region (106) of the substrate and outside the second substrate region (107).

18. The document according to any one of claims 1 to 17, characterized in that the document comprises at least one additional third region (110) on which the substrate (101) is covered with an effect layer (104) of a material which is susceptible to deformation under external pressure and reflects light, having a high light reflectance coefficient, and a second print layer (103) of a colorful material as a covering medium, on which a third optical security feature in the form of a colorful tactile rotogravure-printed indicia is provided.

19. A process for the manufacture of a matrix (502) for making the secured document (100) as defined in any one of claims 1-18, said process comprising the steps of: a) selecting a color source image corresponding to the marking to be applied, preferably an image, motif, pattern or character of the first security element (102); b) designing a color initial image (601) for the first security element (102), in which step, after processing the source image for the first security element (102), preferably by means of a computer configured to design graphic images, to produce a graphic image that is ultimately to be perceived by the naked eye on a first substrate region (106) of the secured document, a set of input data is determined defining the desired marking of the first security element (102) as a grid (400) of single-color cells (401), which cells (401) are assigned a color averaged over the area of a single cell (401) defined in the RGB scale; c) converting, by means of a computer configured to perform such conversion, the designated input data corresponding to the initial image into a graphic file describing the color initial image as a grayscale image; d) assigning to the specific color of each cell (401) expressed on a gray scale, a specific degree of inclination of parallel lines, said degree of inclination being in the range from 1 to 180°, and where the extreme values of the degree of inclination correspond to the extreme colors, in particular the colors white and black, respectively; e) selecting a source image for the second security element (105); f) designing a color initial image (601) for the second security element (105), in which step, after processing the source image for the second security element (105), preferably by means of a computer configured to design graphic images, to produce a graphic image that is ultimately to be perceived by the naked eye on a second substrate region (107) of the secured document (100), a set of input data is determined defining a desired image of the second security element (105) as a graphic design for printing; g) combining a set of input data defining an image of the first security element (102) and the second security element (105) into one set of input data defining a security feature of the secured document (100); h) forming a gravure-printing matrix (502), preferably by etching, laser engraving or mechanically engraving the plate in accordance with the set of input data defining a security feature of the secured document (100) by etching, under the control of a computer configuredtherefor, a surface of the matrix (502) to produce, in the first region (106), an arrangement of cells (401) of a grid (400), said cells (401) comprising a set of at least three mutually parallel linear recesses, and in the second region (107) a representation of a marking corresponding to the second security element (105), to produce recesses in the matrix (502) defining the contours of the marking to be applied; i) curing the matrix (502).

20. The process for the manufacture of the matrix (502) according to claim 19, characterized in that the step i) of curing the matrix (502) comprises manufacturing target production printing plates by electroplating methods.

21. The process for the manufacture of the matrix (502) according to claim 19, characterized in that the step i) of curing the matrix (502) comprises coating the matrix (502) with a material having increased mechanical parameters.

22. A process for the manufacture of the secured document as defined in any one of claims 1-18 using the matrix (502) obtained by the process as defined in claims 19-21, comprising the steps of: a) covering (5.1-5.3) the first region (106) of the substrate (101) with an effect layer (104) of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflectance coefficient; b) coating (5.4) all the recesses on the second region of the matrix (502) with a color coating material; c) pressing (5.5 -5.6) the matrix (502) with- deforming under the pressure force the light-reflecting material having a high light reflectance coefficient on the first region (106) of the substrate (101) and reproducing the recesses in the matrix (502) on the first region (106) of the substrate (101) in the effect layer (104) material deformable under an external pressure force and forming a marking corresponding to the first security element (102), and- transferring the color coating material from the matrix recesses (502) to the substrate (101) in the second region (107) of the substrate (101) with reproducing the marking corresponding to the second security element (105).

23. The process according to claim 18, characterized in that covering (5.1-5.3) the first region (106) of the substrate (101) with the effect layer (104) made of a material susceptible to deformation under the influence of an external pressure force and reflecting light, having a high light reflection coefficient, is carried out by means of offset printing, letterpress printing, screen printing, flexographic printing, hot-stamping, cold-stamping technique, preferably by means of the hot-stamping technique.

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