See-through security element

Abstract

The invention relates to a see-through security element (2), a security document (1), and a method for producing a see-through security element (2). The see-through security element has a first element with one or more transparent first sub-regions and at least one reflective second sub-region. The see-through security element has a second element with one or more first sub-regions, each of which forms a color filter during transmission, said color filter being calibrated for a respective assigned color, and at least one second sub-region, which is designed to be colorless, in particular colorlessly transparent, or which forms a color filter during transmission and / or reflection, said color filter being calibrated for a color that is not assigned to any of the one or more first sub-regions of the second element. The first sub-regions of the first element and the first sub-regions of the second element at least partly overlap.

Description

[0001] The invention relates to a see-through security element, a method for producing a see-through security element and a security document with a see-through security element.

[0002] It is known to incorporate see-through security elements into security documents, particularly banknotes. These elements are usually in the form of security threads. For this purpose, a plastic film is coated with an opaque layer. Recesses are then made in the opaque layer, which contain alphanumeric characters in reverse. When viewed in transmitted light, these characters become visible as colorless, light-colored characters against a dark background.

[0003] WO 2011 / 006634 A2 describes a method for producing a multilayer body and a multilayer body.

[0004] DE 10 2010 054 760 A1 describes a security element, a method for producing the same and a data carrier.

[0005] DE 10 2017 106 545 A1 describes a method for producing an optical security feature as well as a security element and a security document.

[0006] The invention is based on the object of providing improved see-through security elements and a method for producing such elements.

[0007] The problem is solved by a see-through security element according to claim 1.

[0008] To produce this see-through security element, one or more color layers are applied to the first element, the solubility and / or color filter effect of which can be changed by means of exposure, and the one or more color layers are exposed through the first element using the first element as an exposure mask, wherein the one or more first partial regions of the second element are formed by at least one translucent color layer or a sequence of layers comprising at least one translucent color layer, and wherein the first element is first created and then the first element is used as an exposure mask for structuring one or more layers of a second element.

[0009] The invention achieves the advantage of further improving the counterfeit security of see-through security elements. Thus, the invention makes it possible to provide see-through security elements that display colored features when viewed in transmitted light and, in particular, that display a different colored appearance and / or different motifs when viewed in reflected and transmitted light. Because these various security features are provided by the interlinked elements of the security elements, their imitation and counterfeiting attempts are made more difficult. This is also because the security features newly provided by the invention are particularly concise and memorable, so that counterfeit attempts can be quickly detected.

[0010] Advantageous embodiments of the inventions are defined in the subclaims.

[0011] Preferably, in the first region of the see-through security element, the first sub-regions of the first element and the first sub-regions of the second element are arranged in such precise register with one another when viewed perpendicular to the plane spanned by the first main surface that a first colored feature becomes visible in the first region when viewed in transmitted light, which first colored feature is not visible or almost not visible, in particular when viewed in reflected light from the front and back. For the viewer, the first feature that appears in transmitted light is, for example, a singly or multiply colored design element that is visible in transmitted light and not visible or almost not visible in reflected light. The production of such a security element places high demands on the register accuracy of the arrangement of the sub-regions of the first and second elements, making these security elements very difficult to forge and imitate.

[0012] Register or registration or registration accuracy or registration accuracy is preferably understood to mean a positional accuracy of two or more elements and / or layers, here in particular of the elements and / or sub-areas.

[0013] The register accuracy should be within a specified tolerance and as low as possible. At the same time, the register accuracy of multiple elements, sub-areas, especially one or more foil elements, foils, layers, and / or layers, relative to each other is an important feature for increasing process reliability.

[0014] Precise positioning is achieved in particular by means of markings, in particular by means of sensor-detectable, preferably optically detectable, registration marks or register marks. These markings, in particular registration marks or register marks, preferably represent either specific separate elements, regions, or layers or are preferably themselves part of the elements, regions, or layers to be positioned.

[0015] A colored feature preferably represents a feature that, at least in some regions, has one or more colored regions, i.e., regions colored in one color. In addition to such colored regions, a colored feature may have several consecutive colorless regions, which, for example, appear light or dark.

[0016] The color of transmitted or reflected light can be quantified by specifying a color location in a color system. For the purposes of this application, the color of a feature or a sub-area of a feature is described by the chroma or chromaticity C* in the CIEL*a*b* color space. C* is defined as C ∗ = a ∗ 2 + b ∗ 2

[0017] The L* value, which is perpendicular to the color plane (a*, b*), is a measure of the brightness of the color.

[0018] Preferably, a colored feature in transmitted light when viewed perpendicularly has at least one partial area that has a chroma C* greater than 10, particularly preferably C* greater than 20. The light source is assumed to be the standard illuminant D65 and the 10° CIE standard observer.

[0019] Preferably, in the first region of the see-through security element, the one or more first sub-regions of the first element are each completely enclosed by the at least one second sub-region of the first element, and / or the one or more first sub-regions of the second element are each completely enclosed by the at least one second sub-region of the second element. Investigations have shown that with such a design of the first and second elements in the first region, a particularly high color contrast can be achieved between the colors which the see-through security element displays when viewed in transmitted light in the first region and which the see-through security element displays in the first region when viewed in reflected light from the front and / or back. This further improves security against counterfeiting.

[0020] Preferably, in the first region of the see-through security element, the one or more first partial regions of the first element provided there and / or the one or more first partial regions of the second element provided there each have a dimension of less than 500 µm, preferably less than 300 µm, in at least one lateral direction. Further preferably, in the first region, the one or more first partial regions of the first element and the one or more first partial regions of the second element each have a dimension of between 5 µm and 300 µm, preferably between 10 µm and 200 µm, further preferably between 15 µm and 150 µm, in at least one lateral direction.

[0021] The lateral direction is understood here to mean a direction that lies in the plane spanned by the first main surface of the see-through security element. Thus, for example, when viewed perpendicular to the plane spanned by the first main surface of the see-through security element, the subregions have a width dimension of less than 500 µm, preferably less than 300 µm, and optionally also preferably a length dimension of less than 500 µm, preferably less than 300 µm.

[0022] Investigations have shown that this measure, on the one hand, sufficiently preserves the visibility of the first colored feature in transmitted light viewing, and on the other hand, the first colored feature is almost invisible when viewed in reflected light from the front and / or back.

[0023] For alternative embodiments, it may be advantageous for the first colored feature to be partially or completely visible both in incident light and in transmitted light. For this purpose, it is advantageous if, in the first region, the one or more first partial regions of the first element and the one or more first partial regions of the second element each have a dimension of more than 300 µm, preferably more than 500 µm, particularly preferably more than 700 µm, in at least one lateral direction.

[0024] Not according to the invention, in the first region of the see-through security element, the first partial regions of the second element each overlap congruently with an associated partial region of the first element when viewed perpendicular to the plane spanned by the first main surface. This further increases the color contrast between the optical appearance of the first region when viewed in reflected light and in transmitted light. Studies have shown that this measure prevents and / or largely prevents first partial regions of the second element in the first region from influencing the color when viewed in reflected light from the front and back. This also increases the requirements for register accuracy, so that forgery security is further improved.

[0025] In the first region of the see-through security element, the first sub-regions of the first element are assigned to a first group of first sub-regions and a second group of first sub-regions. The one or more first sub-regions of the first element assigned to the first group each overlap congruently with an assigned first sub-region of the second element when viewed perpendicular to the plane spanned by the first main surface. The one or more first sub-regions of the first element assigned to the second group each overlap with the at least one second sub-region of the second element. This makes it possible to provide a colored first feature when viewed in transmitted light, which is multi-colored and has differently colored sub-regions and / or has colorless sub-regions in addition to colored sub-regions.

[0026] Preferably, the one or more first subregions of the first element and the one or more first subregions of the second element are each formed in the form of a line and / or a raster element. Studies have shown that a line-based formation of the subregions can achieve particularly large contrast differences in reflected and transmitted light viewing, particularly when motifs or sub-motifs of the first feature are composed of fine solid or dotted lines.

[0027] Preferably, one or more first subregions of the first element and one or more first subregions of the second element are each formed in the first and / or second region in the form of a thin, continuous line or sections of a line. The width of the line is preferably selected between 5 µm and 300 µm, preferably between 10 µm and 200 µm, more preferably between 15 µm and 150 µm. The lines preferably each form a line of a motif or sub-motif of the first feature.

[0028] Furthermore, it is also possible to locally vary the spacing and / or width of the lines. This makes it possible, on the one hand, to locally vary the brightness of the first feature and, if necessary, to integrate additional "second line" security features into the security element, which are only detectable with a technical aid, such as a magnifying glass or a microscope.

[0029] Furthermore, it is advantageous to form flat motifs or partial motifs of the first feature using raster elements, and to shape the one or more first partial regions of the first element and / or the one or more first partial regions of the second element as corresponding raster elements, which are arranged in the form of a one- or two-dimensional raster. The raster elements preferably have a dimension between 5 µm and 300 µm, preferably between 10 µm and 200 µm, more preferably between 15 µm and 150 µm in at least one lateral direction, and preferably in all lateral directions. The raster elements can be shaped as square, circular, rectangular, and / or elliptical, and / or alphanumeric, and / or motif-shaped raster elements.Furthermore, it is also possible for the grid elements to have any other shape and thus, for example, to be designed in the form of an alphanumeric character, in particular in the form of micro-writing.

[0030] The first partial regions of the first and / or second element forming the raster elements are preferably arranged in such a way with respect to their spatial arrangement relative to one another that they form a motif or partial motif of the first and / or second feature and are thus provided, for example, in a region whose shape corresponds to the shape of the motif or partial motif. It is also possible here for the grid width of the grid and / or the size of the raster dots to be varied locally, in particular in order to locally vary the brightness of the partial motif or motif of the first feature accordingly. This makes it possible to provide a first and / or second colored feature which has regions not only with different colors or chromaticity, but also with different brightness.

[0031] The grid width of the grid is preferably selected between 5 µm and 300 µm, more preferably between 10 µm and 200 µm, and even more preferably between 15 µm and 150 µm. Furthermore, it is also possible for the grid to be a linear grid in which the grid elements follow one another in the direction of a line. This makes it possible to combine the advantages of a line-based and area-based formation of the first and / or second colored feature.

[0032] Preferably, the area proportion F of the one or more first partial regions of the first element is less than 20%, preferably less than 10%, more preferably less than 5%. The area proportion F is the ratio of the area of the first region occupied by the one or more first partial regions of the first element to the area of the first region occupied by the one or more first partial regions and the at least one second partial region of the first element. Preferably, the first region of the see-through security element is the smallest possible rectangular region in which each edge of the rectangular region adjoins the first feature at at least one point, when viewed perpendicular to the plane spanned by the first main surface.

[0033] This has the advantage that the visibility of the first colored feature is reduced or preferably almost completely prevented in reflected light viewing and is only made possible in transmitted light viewing and this first colored feature becomes particularly clearly visible.

[0034] Preferably, the at least one second partial region of the first element completely encloses the first region of the see-through security element when viewed perpendicular to the plane spanned by the first main surface. Preferably, the at least one second region of the first element extends from the first region of the see-through security element at least by a distance d when viewed perpendicular to the plane spanned by the first main surface, where d is greater than 0.5 mm, in particular greater than 0.8 mm, more preferably greater than 1 mm. Thus, the second partial region of the first element preferably completely encloses the first region in all directions, starting from the first region, by at least the distance d.

[0035] These measures also lead to the visibility of the first colored feature being further improved when viewed in transmitted light, thus making the first feature appear more clearly to the viewer.

[0036] Preferably, in the second region of the see-through security element, at least one of the first partial regions of the first element and at least one of the first partial regions of the second element are arranged in such precise register with one another when viewed perpendicular to the plane spanned by the first main surface that a second colored feature becomes visible in the second region when viewed in transmitted light, which second colored feature is directly adjacent to a third feature visible from the front and / or back when viewed in reflected light. This has the advantage that the third feature serves as a reference for the second colored feature and thus attempts at forgery and registration deviations are easily detectable for the viewer. This further improves the forgery security of the security element.

[0037] Preferably, in the at least second region of the see-through security element, at least one of the first partial regions of the second element overlaps with a first partial region of the first element when viewed perpendicular to the plane spanned by the first main surface such that the at least one first partial region of the second element only partially overlaps the first partial region of the first element, preferably overlaps by less than 50%, more preferably overlaps by less than 30%.

[0038] This ensures that a second colored feature can be provided in the second region when viewed in transmitted light, which differs from the shape of the first element. Furthermore, it is advantageous if the at least one first partial region of the second element forms a motif that differs from the shape of the overlapped first partial region of the first element, which becomes visible as a colored second feature when viewed in transmitted light in the second region. This provides the advantage that the recognizability of the second colored feature is further improved when viewed in transmitted light.

[0039] Preferably, despite the formation of a different motif, the at least one first partial region of the second element is largely directly adjacent to the at least one second partial region of the first element in some areas, preferably without overlap and without a visible gap. This provides the advantage that register deviations can be easily detected, thus further improving counterfeit security.

[0040] Preferably, in the second region of the see-through security element, the first partial regions of the second element each have an overlap of no more than 100 µm, preferably no more than 50 µm, more preferably no more than 10 µm with the at least one second partial region of the first element, when viewed perpendicular to the plane spanned by the first main surface. This provides the advantage that a particularly high color contrast can be achieved between the transmitted-light and reflected-light views of the security element.

[0041] Preferably, in the first and / or second region of the see-through security element, the first partial regions of the second element do not overlap with the at least one second partial region of the first element, when viewed perpendicular to the plane spanned by the first main surface.

[0042] Preferably, in the first and / or second region of the see-through security element, the at least one second subregion of the first element and the one or more first subregions of the second element adjoin one another without overlap when viewed perpendicular to the first main surface and, at least in some regions, with a gap of a width S of less than 300 µm, preferably less than 50 µm, more preferably seamlessly. This provides the advantage that, on the one hand, the color contrast between incident light and / or transmitted light viewing can be improved and, furthermore, register deviations and attempted counterfeiting are immediately recognizable to the viewer.

[0043] Preferably, in the first and / or second region, a third feature determined by at least one of the second partial regions of the first element is visible when viewed in reflected light from the front side and / or a third feature determined by at least one of the second partial regions of the first element is visible when viewed in reflected light from the back side. Preferably, the third features visible when viewed in reflected light from the front and back side differ from one another, particularly in their color. This further improves counterfeit security.

[0044] Preferably, a colorless fourth feature determined by the shape of at least one of the first partial regions of the first element is visible in the second region when viewed in transmitted light. This further increases the security against counterfeiting.

[0045] Preferably, the at least one second subregion of the first element has an optical density of more than 0.8 OD, preferably more than 1.1 OD, more preferably more than 1.3 OD, and particularly preferably more than 1.5 OD, averaged over the visible wavelength range. The colors visible to humans lie in the range between 380 nm [violet] and 780 nm [deep red] of the electromagnetic spectrum, with the relative sensitivity of the eye below 430 nm and above 690 nm being less than 1% of the maximum value at 555 nm. Therefore, the visible wavelength range is understood here to mean, in particular, the wavelength range between 430 nm and 690 nm.

[0046] The one or more first subregions of the second element preferably have an associated L* value (CIEL*a*b* color space) greater than 5, preferably greater than 10, more preferably greater than 20 when measured in transmission.

[0047] The above measures further improve the visibility of the first and fourth features in transmitted light viewing, probably by improving the contrast.

[0048] The at least one second partial region of the first element has, in particular with respect to a pure mirror surface, a reflectivity averaged over the visible wavelength range of more than 40%, more preferably of more than 70%.

[0049] Reflectivity is the proportion of the incident light that is reflected, scattered or diffracted.

[0050] "Transparent" is understood to mean, in particular, an average light transmittance in at least one wavelength range of visible light, preferably in the visible wavelength range (in particular between 430 nm and 690 nm), and in particular across the entire spectrum of visible light of more than 30%, more preferably more than 50%, and preferably more than 80%. This light transmittance is preferably measured perpendicularly through the security element.

[0051] The one or more first partial regions of the first element are preferably reflective. By reflective is meant that more than 10%, more preferably more than 20% of the light incident on the one or more first partial regions is reflected back, backscattered or back-diffracted from the front and / or back side when viewed in incident light, for at least one wavelength range, preferably averaged over the visible wavelength range (in particular between 430 nm and 690 nm). The one or more first partial regions of the first element can be reflective, for example, by applying a highly refractive material, e.g. ZnS or TiO 2 , or by applying a very thin metal layer, e.g. an aluminum layer with a transmission in the range from 0.1 OD to 0.5 OD.

[0052] Investigations have shown that such a design of the one or more first partial areas "obscures" the visibility of the first feature when viewed in incident light, in particular in combination with the measures already specified above, i.e. in particular a corresponding design of the one or more first partial areas of the first elements with at least one lateral dimension of less than 300 µm, preferably between 5 µm and 300 µm, more preferably between 10 µm and 200 µm, more preferably between 15 µm and 150 µm.

[0053] Preferably, the at least one second partial region of the first element is formed by at least one metallic layer or a sequence of layers comprising at least one metallic layer. The at least one metallic layer is preferably not provided and / or removed from the one or more first partial regions of the first element. When using one or more metallic layers, it has proven useful to strive for the above-mentioned requirements regarding the reflectivity and optical density of the at least one first partial region of the first element and thus to ensure that the first colored feature is visible when viewed in transmitted light, but is "obscured" when viewed in reflected light.

[0054] Instead of one or more metallic layers applied by means of a metallization process, for example vacuum deposition, it is also possible to print layers containing metallic pigments.

[0055] Preferably, the at least one second partial region of the first element has a second relief structure and at least one reflective layer, which follows the contour of the relief structure on at least one main surface, preferably on both main surfaces. The reflective layer is preferably a metallic layer.

[0056] The second relief structure, in combination with the reflective layer, preferably provides an optically variable third feature, in particular in the first and / or second region of the see-through security element. It is also possible for the at least one second partial region of the first element to have not only one reflective layer that follows the contour of the relief structure on at least one main surface, but preferably two or more such reflective layers that preferably follow different relief structures on at least one main surface. This makes it possible to generate different optically variable third features when viewed in reflected light from the front and back, thus further improving the forgery security of the security element.

[0057] Preferably, the see-through security element further comprises a third element, which has one or more transparent first partial regions and at least one reflective second partial region. The second element is preferably arranged between the first element and the third element in the see-through security element, particularly when viewed perpendicular to the plane spanned by the first main surface.

[0058] The third element is preferably designed like the first element, so that reference is made to the relevant previous explanations regarding the first element.

[0059] The one or more transparent first subregions of the first element and the one or more transparent first subregions of the third element preferably overlap at least in some regions, in particular overlap congruently. Furthermore, it is advantageous if the at least one reflective second subregion of the first element and the at least one reflective second subregion of the third element overlap at least in some regions, preferably overlap congruently, when viewed perpendicular to the plane spanned by the first main surface.

[0060] This further provides the advantage that, with appropriate design of the first element and the second element, the optical appearance of the see-through security element when viewed in reflected light from the front and back shows correspondingly different optical effects and, moreover, the advantages of the invention described above, in particular the previously described reflected light / transmitted light behavior, are retained.

[0061] Furthermore, it is advantageous if one or more of the first partial regions of the second element at least partially overlap the at least one second partial region of the first element and / or the third element. This makes it possible for the one or more first partial regions of the second element, which each form a color filter matched to a respective assigned color in transmission, to be provided by a colored lacquer layer, wherein this colored lacquer layer is applied partially and partially overlapping with the second regions of the first element and / or third element. The colored lacquer layer is preferably provided between the two opaque and superimposed reflective layers, which are provided on the one hand by the first element and on the other hand by the third element.

[0062] Preferably, one or more first partial regions of the first element have a first relief structure. The first relief structure is preferably a relief structure that exhibits an optically variable effect when viewed in transmitted light. This makes it possible to integrate further optically variable effects into the first and / or second feature.

[0063] As already stated above, the first and / or second relief structure is preferably a relief structure that generates an optically variable effect. These relief structures are preferably a relief structure selected from: a diffractive structure, in particular a hologram, a zero-order diffraction grating, a matte structure, in particular an anisotropic matte structure, an achromatic structure, in particular a microlens structure, a micromirror structure, or a microprism structure.

[0064] Optically variable effects, preferably motion effects and / or color change effects, are provided. Studies have shown that this further obscures the visibility of the first feature for the human observer when viewed in incident light.

[0065] Preferably, the at least one second partial region of the first element exhibits a color-shift effect when viewed in reflected light from the front and / or back. For this purpose, the at least one second partial region of the first element comprises, in particular, a thin-film layer stack for generating a color-shift effect by means of interference and / or at least one liquid crystal layer and / or one or more layers comprising optically variable pigments, in particular interference layer pigments. This measure provides, when viewed in reflected light from the front and / or back, further optically variable effects, in particular in the third feature, and thereby further improves counterfeit security.

[0066] The one or more second subregions of the first element preferably comprise a volume hologram. This volume hologram provides, when viewed in reflected light from the front and / or back, preferably optically variable effects in the third feature. This measure also further improves counterfeit security.

[0067] Preferably, the at least one second partial region of the first element comprises one or more lacquer layers, which are colored in particular by means of a colorant, in particular a dye and / or a colored pigment. These measures make it possible to provide third features of different colors when viewed from the front and back sides in reflected light, thus further improving counterfeit security.

[0068] The measures described above for forming the at least one second partial region of the first element can be combined with one another in any desired manner. Furthermore, the layers proposed above for this purpose can also be provided only in certain regions and in particular in a pattern in the at least one second partial region of the first element, so that the effects described above are only provided in certain regions by the at least one second partial region of the first element. Preferably, the layers specified above for this purpose are not provided or are removed in the one or more first partial regions of the first element in order to thus make the one or more first partial regions of the first element transparent.

[0069] The color or colors of the first and / or second colored features preferably correspond to the color or colors assigned to the one or more first subregions of the second element.

[0070] However, it is also possible for the see-through security element to have one or more additional color filter layers, which at least partially overlap the one or more first partial regions of the second element, when viewed perpendicular to the plane spanned by the first main surface of the see-through security element. This makes it possible to further influence the color or colors of the first colored features by appropriate color mixing, in order to achieve a corresponding deviation of the color or colors of the first colored feature from the color or colors assigned to the one or more first partial regions of the second element.

[0071] Preferably, the color or colors of the first colored feature do not match any color exhibited by the see-through security element in the first region when viewed in incident light from the front and / or back. This further improves the detectability of the first colored feature and thus also further improves the forgery resistance of the see-through security element.

[0072] According to one embodiment, the first and / or second colored feature is formed in a single color. This is preferably achieved in particular by assigning the same color to one or more first partial regions of the second element in the first and / or second regions of the see-through security element.

[0073] By designing the first and / or second feature in a single color, the recognizability of the first and / or second colored feature is improved.

[0074] According to a further embodiment, the first and / or second colored feature is multicolored and has partial areas with different colors.

[0075] For this purpose, in the first or in the first and second regions of the see-through security element, the first subregions of the second element are assigned to two or more groups of subregions. Each of the groups of first subregions is assigned a respective color. The colors assigned to the groups differ from one another. The color filters formed in the respective first subregions are matched to the respectively assigned color.

[0076] In particular, a first color is assigned to each of a first group of first subregions of the second layer, a second color is assigned to each of a second group of first subregions of the second layer, and optionally a third color is assigned to each of a third group of first subregions of the second layer. The first, second, and third colors differ from one another.

[0077] This measure makes it possible to design the first and / or second security feature in multiple colors and thus further improve the security against counterfeiting due to the requirements of the precise registration of different color filters.

[0078] The one or more first partial regions of the second element are formed by at least one translucent color layer or a sequence of layers comprising at least one translucent color layer. The at least one translucent color layer is preferably not provided and / or removed in at least one second partial region of the second element.

[0079] The translucent color layer preferably consists of a lacquer, in particular a photoresist, which is colored with a colorant, in particular a dye or a pigment, such that the color layer forms a color filter in transmission which is matched to the assigned color.

[0080] The second element further preferably has a photochromic layer or is formed by a photochromic layer which is activated by irradiation in the one or more first partial regions of the second element and is not activated in the at least one second partial region of the second element, or vice versa. The activation of the photochromic layer preferably takes place by irradiation with a wavelength outside of visible light, for example by means of UV radiation. The photochromic layer is formulated accordingly in order to provide the corresponding color filter effects, as described above, in the one or more first partial regions of the second element and the at least one second partial region after exposure.

[0081] To produce the see-through security element, it has also proven effective to first create the first element and then use the first element as an "exposure mask" for structuring one or more layers of the second element. This makes it possible to "position" the first and / or second sub-regions of the second element in precise register with the first and / or second sub-regions of the first element, thereby achieving the effects described above.

[0082] As already explained above, the first element preferably has at least one or more metal layers. These one or more metal layers are preferably removed in the one or more first partial regions of the first region by demetallization in order to achieve the optical properties described above in the one or more first partial regions.

[0083] As soon as the first element is manufactured, one or more color layers are preferably printed, preferably by means of a printing process, preferably only partially printed on the first element. The one or more color layers are preferably printed next to one another and / or overlapping on the first element. It is also advantageous if two or more different color layers are printed, in particular color layers are printed which each form color filters in transmission that are matched to different colors. These two or more different color layers can be applied next to one another and / or partially overlapping on the first element.

[0084] The one or more color layers are preferably each formed from a colored, negative radiation-sensitive or radiation-activatable photoresist and / or from a photochromic material, as already explained above.

[0085] Furthermore, it is possible that one or more, in particular colored, blocking layers are additionally applied to the first element, in particular printed in a pattern.

[0086] A blocking layer is understood to be a layer which is so "opaque" to the wavelength used for exposure or irradiation that any underlying photoresist layers and / or photochromic layers are not activated by the exposure.

[0087] The blocking layer, like the colored photoresist layer, can be partially applied using digital printing, for example, inkjet printing. This allows for the creation of individual markings for individual see-through security elements.

[0088] A colored photoresist layer can also be applied over the entire surface and exposed only partially. This exposure can be achieved, for example, using a mask and / or controllable UV light-emitting diodes.

[0089] After application of this layer, a corresponding exposure of the one or more color layers by the first element takes place, whereby a corresponding activation of the photochromic layer or, in particular, the negative photoresist takes place in register with the one or more first partial areas of the first element.

[0090] The security element is preferably designed as a laminating film, a transfer film or an inlay.

[0091] The see-through security element preferably takes the form of a security thread, a security strip, or a patch. However, the see-through security element can also be provided over the entire surface of a security document, for example, an ID document.

[0092] The see-through security element is preferably integrated as a security element into a security document, for example into an ID document, a banknote, a security and / or a certificate. In this case, it is advantageous if the security document has a transparent or translucent layer structure at least in some regions or has one or more recesses in the form of windows. The see-through security element is applied to the security document and / or integrated into the layer structure of the security document in such a way that the see-through security element at least partially overlaps a transparent or translucent region of the security document and / or one or more of the windows introduced into the security document, when viewed perpendicular to the plane spanned by the first main surface of the security element.

[0093] In an alternative embodiment, the see-through security element is applied or integrated onto or into a security document such that it does not overlap with a transparent or translucent area of the security document and / or with one or more of the windows incorporated into the security document. It is advantageous if the security document is still sufficiently translucent in the area of the applied see-through security element so that the see-through security element can still be verified, similar to a watermark on a banknote. A sufficiently translucent security document, for example, is a paper banknote, since when held up to a bright light source, a sufficient amount of light passes through it for the human eye to verify the see-through security element.

[0094] In the following, the invention is explained by way of example using several embodiments with the aid of the enclosed figures. Fig. 1a und Fig. 1b show a top view of a security document with a see-through security element. Fig. 1c shows a top view of a see-through security element. Fig. 1d shows a sectional view of a see-through security element. Fig. 2 shows a top view of a see-through security element. Fig. 3 shows a top view of a see-through security element. Fig. 4a und Fig. 4b each show a top view of a see-through security element. Fig. 5a bis Fig. 5d each show a top view of a see-through security element. Fig. 6a und Fig. 6b each show a top view of a see-through security element. Fig. 7a und Fig. 7b each show a top view of a section of a see-through security element. Fig. 8a shows a top view of a section of a see-through security element. Fig. 9 shows a top view of a section of a see-through security element. Fig. 10 shows several top views of respective sections of a see-through security element. Fig. 11a bis Fig. 11f each show sectional views to illustrate a process for producing a see-through security element. Fig. 12a bis Fig. 12f each show sectional views to illustrate a process for producing a see-through security element. Fig. 13a bis Fig. 13h each show sectional views to illustrate a process for producing a see-through security element. Fig. 14a bis Fig.14f each show sectional views to illustrate a process for producing a see-through security element. Fig. 15a bis Fig. 15i each show sectional views to illustrate a process for producing a see-through security element. Fig. 16 shows a top view of a see-through security element and a section of this see-through security element. Fig. 17a shows a cross-sectional view of a security document with two see-through security elements. Fig. 17b shows schematic top views of see-through security elements and image information. Fig. 17c shows a sectional view to illustrate a method for producing a see-through security element. Fig 18a and Fig. 18b each show sectional views to illustrate a process for producing a see-through security element.

[0095] Fig. 1 shows a schematic top view of a security document 1. The security document 1 is preferably a banknote. However, it is also possible that the security document 1 is, for example, an ID document, a certificate, or a ticket.

[0096] The security document 1 has a substrate 10 into which a transparent window 11 is introduced.

[0097] The substrate 10 is preferably a paper substrate, a plastic substrate, and / or a substrate comprising paper and plastic layers. The window 11 can be introduced into the substrate 10 by providing a recess in this region in the substrate 10 of the security document 1 and / or by making the layers of the substrate 10 provided there transparent in this region.

[0098] In the area of the window 11, a window security element 2 is provided in the security document 1. The window security element 2 can, as in Fig. 1a indicated, have a patch shape, for example a size of 28 mm x 21 mm. Preferably, the see-through security element 2 overlaps the window 11 at least in some areas and preferably covers the window 11 completely. As for example in Fig. 1a As shown, the see-through security element 2 preferably has a larger size than that of the window 11, completely overlaps the window 1 and further has an outer contour that differs from the window 11, here for example a rectangular outer contour with rounded corners, compared to the circular boundary line of the window 11.

[0099] The security element 2 is preferably applied to one of the main surfaces of the substrate 10, for example in the form of a laminating or transfer film applied to one of the main surfaces of the substrate 10.

[0100] However, it is also possible for the see-through security element 2 to be integrated into the layer structure of the substrate 10, for example by being introduced during the manufacturing process into a paper layer of the substrate, between two paper layers of the substrate 10 and / or, if appropriate also over the entire surface, between plastic layers of the substrate 10.

[0101] Furthermore, it is also possible for the see-through security element 2 to have a different shape. For example, the see-through security element 2 can be designed in the form of a security thread or security strip, which in particular spans the entire area of this security document from one longitudinal edge to another longitudinal edge.

[0102] Furthermore, it is also possible for the see-through security element to have the same size as the substrate 10 and to be applied over the entire surface of the substrate 10 or to be integrated between layers of the substrate 10. This is particularly advantageous when the security document 1 is a card-shaped security document, for example in the form of an ID document or the data page of a book-shaped document.

[0103] The security document 1 is preferably printed on the front and / or back and / or provided with additional security elements. For example, the security document 1 has Fig. 1a shown front side further security features 12. The security features 12 are, for example, an imprint with a security ink, for example an optically variable ink, and / or further, preferably optically variable security elements, which are applied to the substrate 10 or integrated into the substrate 10.

[0104] In according to the embodiment Fig. 1a und Fig. 1b clarified Fig. 1a a schematic plan view of the front of the security document 1 and Fig. 1b a schematic plan view of the back of security document 1.

[0105] In this exemplary embodiment, the see-through security element 2 is applied to the front side of the substrate 10. When viewed from the front side in reflected light, the see-through security element 2 generates a feature 33, in particular an optically variable feature 33; when viewed from the back side in reflected light, a feature 34, in particular an optically variable feature 34; and when viewed in transmitted light, a colored feature 31. The optically variable features 33 and 34 can represent identical motifs, except for a mirrored appearance. However, the optically variable features 33 and 34 can also represent different motifs.

[0106] Fig. 1c shows, by way of example, the colored features 31, which are visible in a respective area 41 when viewed in transmitted light. These colored features 31 are, on the one hand, a colored symbol in the shape of a "sun" and, on the other hand, the lettering "KINEGRAM", which are visible here when viewed in transmitted light. The colored areas are in Fig. 1c indicated by white lines.

[0107] The basic structure of the see-through security element 2 is shown schematically in Fig. 1d Shown: The see-through security element 2 has a first main surface 201 and a second main surface 202 opposite it. The main surface 201 forms the front side of the see-through security element 2, and the main surface 202 forms the back side of the see-through security element 2.

[0108] The see-through security element 2 comprises a first element 21, a second element 22 and optionally one or more further layers, of which Fig. 1d a carrier layer 23, a lacquer layer 24 and an adhesive layer 25 are shown.

[0109] The carrier layer 23 is formed, for example, from a plastic film, for example a PET film or PC film (PC = polycarbonate) with a thickness between 10 µm and 300 µm. This substrate layer 23 can also comprise a plurality of layers, for example one or more additional lacquer layers and / or adhesion-promoting layers and / or release layers. The carrier layer 23 preferably has one or more release or adhesion-promoting layers on its side oriented towards the lacquer layer 24. If one or more release layers are provided here, the see-through security element 2 is a transfer film. If one or more adhesion-promoting layers are provided, the see-through security element is a laminating film. However, it is also possible to dispense with such release and / or adhesion-promoting layers and / or the carrier layer 23.This is particularly the case when the see-through security element 2 is arranged between one or more layers of the security document 1 and / or the window 11 is not formed by an opening in the substrate 10 of the security document, but by a transparent area of the security document 1.

[0110] The lacquer layer 24 preferably consists of a protective lacquer layer and / or a lacquer layer in which a relief structure is molded. It is also possible for two or more such lacquer layers 24 to be provided in the see-through security element 2.

[0111] The lacquer layer 24 is preferably arranged between the carrier layer 23 and the first element 21 in the see-through security element 2.

[0112] The first element 21 has one or more first transparent partial regions 211 and at least one reflective, in particular highly reflective, second partial region 212.

[0113] The first element 21 preferably has one or more metal layers, for example consisting of aluminum, copper, gold, silver, chromium. The one or more metal layers of the first element 21 are preferably not provided in the one or more first partial regions 211 or are removed again by demetallization, so that the transparency of the first element 21 in this partial region is not impaired by the one or more metal layers. Preferably, no layers of the first element 21 are provided in the one or more first partial regions 211 of the first element 21, or only transparent layers of the first element 21 are provided. Furthermore, however, it is also possible for the one or more metal layers in the one or more first partial regions 211 of the first element to be provided with a significantly smaller layer thickness than in the one or more second partial regions 212.

[0114] The one or more metallic layers are preferably applied in a layer thickness between 5 nm and 300 nm, more preferably between 10 nm and 100 nm, for example by means of a vapor deposition process, and then completely or largely removed again in the one or more second partial regions 212 by means of a demetallization process. Alternatively, it is also possible to apply a correspondingly structured metal layer using vapor deposition masks in a correspondingly structured manner such that the one or more metallic layers are present essentially or completely only in the region of the one or more second partial regions 212, but not, or at least only in a very small layer thickness, in the region of the one or more first partial regions 211.

[0115] Instead of or in addition to one or more metallic layers, the first element 21 may also comprise one or more color layers, in particular colored with metallic pigments, a thin film layer system for generating color change effects by means of interference, one or more volume hologram layers and / or liquid crystal layers.

[0116] Furthermore, it is also possible for a relief structure to be molded into one or more of the layers of the first element 21, which relief structure, in particular, generates an optically variable effect. This can be achieved, for example, by molding a relief structure, for example a diffractive and / or refractive relief structure or a hologram, into the lacquer layer 24 by means of thermal replication and / or UV replication, for example in precise register with the one or more second partial regions 212 of the first element 21, and by subsequently vapor-depositing one or more metal layers, a corresponding layer of the first element 21 is produced, in which layer a corresponding relief structure is molded into the surface of a metallic layer, which preferably generates optically variable effects when viewed in incident light.

[0117] Furthermore, the first element 21 can also have a preferably transparent lacquer layer into which a corresponding relief structure is molded on the front and / or back and which is then further provided with a reflective layer on one or both sides.

[0118] In an analogous manner, for example, a corresponding relief structure can be molded in register with the one or more first partial areas 211 and a transparent lacquer layer with a different refractive index can be applied in the one or more first partial areas 211 at the interface to the lacquer layer 24, on the upper side of which the relief structure provided there is then correspondingly molded inversely.

[0119] The relief structure in the one or more first partial regions 211 is preferably designed such that it generates diffractive and / or scattering effects, in particular optically variable effects, when viewed in transmitted light.

[0120] For example, in the embodiment according to Fig. 1a, Fig. 1b and Fig. 1c In at least one second partial region 212, a full-surface metal layer is provided, in the front side of which diffractive and / or refractive microstructures are molded, which, when viewed in reflected light from the front, generate the depiction of a sailboat on the water as well as the denomination 45 and the fictitious currency symbol as feature 33. Feature 33 preferably represents an optically variable feature, so that, for example, the color and / or position of the partial motifs of feature 33, for example the sailboat, the currency symbol, the denomination and the water, changes when the see-through security element 2 is tilted and / or rotated.

[0121] If these relief structures provided in one or more second partial areas 212 are formed into both the front and the back of the one or more metal layers, the result is - as in Fig. 1b schematically shown - a corresponding "mirror-inverted" optically variable impression, further also when viewed from the back, so that feature 34 shows a corresponding optical impression.

[0122] Furthermore, however, it is also possible for two or more reflective layers, in particular opaque metallic layers, into which different relief structures are molded, to be provided in the one or more second partial regions 212, one above the other. This makes it possible to realize differently optically variable features 33 and 34 when viewed from the front and back, which become visible in incident light. For example, feature 34, which appears in incident light when viewed from the back, can show a completely different motif or different sub-motif, i.e., for example, a completely differently designed sailboat or a completely different motif, for example, a portrait or a building or an endless pattern, such as a regular arrangement of many representations of the denomination 45.

[0123] In this embodiment with at least two or more opaque and superimposed reflection layers, it is also possible for the one or more first partial regions 221 of the second element 22, which each form a color filter matched to a respective assigned color in transmission, to be provided by a colored lacquer layer, wherein this colored lacquer layer is applied partially and partly overlapping with the second partial regions 212 of the first element 21.

[0124] According to a preferred embodiment, further below the second element 22 there is a Fig. 1d A third element (not shown) is provided which has one or more first transparent partial areas and at least one reflective, in particular highly reflective, second partial area.

[0125] The one or more first transparent subregions of the third element are preferably designed like the one or more first transparent subregions 211 of the first element 21. The at least one reflective second subregion of the third element is preferably designed like the at least one reflective second subregion 212 of the first element 21. With regard to the design of the third element and its first and second subregions, reference is made to the preceding explanations regarding the first element 21.

[0126] Furthermore, the one or more first transparent subregions 211 of the first element 21 and the one or more transparent subregions of the third element are preferably congruent with one another, when viewed perpendicular to the plane spanned by the first main surface 201. Accordingly, the at least one reflective second subregion 212 of the first element 21 is preferably congruent with the at least one reflective second subregion of the third element.

[0127] Preferably, the colored lacquer layer of the second element 22 is provided between the two opaque and superimposed reflective layers of the first element 21 and the third element. As a result, the areas of the colored lacquer layer that overlap with the second partial areas 221 of the first element 22 and / or the second partial areas of the third element are not visible in incident light from the front or back, nor in transmitted light. The color filter function is visible only in the first areas 211.

[0128] Furthermore, it is also possible for one or more color layers to be provided in the one or more second partial regions 212, which influence the color impression of the feature 33 or 34 visible from the front and / or back when viewed in incident light. For example, if a translucent color lacquer layer is provided on the back of a metal layer in the at least one second partial region 212, the feature 34 visible from the back when viewed in incident light can be additionally colored accordingly, thereby achieving a correspondingly different color impression of the features 33 and 34.

[0129] This can be achieved accordingly by providing a corresponding translucent color layer in the partial areas 212 on the front side of a metallic layer.

[0130] For the simplest possible communication and recognition, the color impressions of features 33 and 34 when viewed in reflected light should be as different as possible from the color impressions of feature 31 when viewed in transmitted light. In particular, the difference between the color impressions should be chosen so that even color-blind people, especially those with red / green color blindness or color blindness, can perceive the difference. In particular, the color impressions in reflected light and transmitted light should differ as clearly as possible in terms of brightness and / or chroma.

[0131] The one or more layers of the first element 21 are preferably formed such that the one or more second partial regions 212, when viewed in reflected light from the front and / or back, have an optical density of greater than 0.8 OD, preferably of more than 1.1 OD, more preferably an optical density of greater than 1.3 OD and particularly preferably of more than 1.5 OD averaged over the visible wavelength range and / or have a reflectivity in the visible wavelength range, based on a pure mirror surface, of more than 40%, more preferably of more than 70% averaged over the visible wavelength range.

[0132] The second element 22 has one or more first subregions 221, each of which forms a color filter in transmission that is matched to a respective assigned color. The second element also has at least one second subregion 222. In the at least one second subregion 222, the second element 22 is colorless, preferably colorlessly transparent. This is achieved, for example, in that the one or more layers provided in the one or more first subregions 221, which form a color filter in transmission, are not provided in the one or more second subregions 222 or are removed again. Furthermore, it is also possible for a color filter to be formed in the at least one second subregion 222 in transmission and / or reflection, which color filter is matched to a color that is not assigned to any of the one or more first subregions 221 of the second element 22.

[0133] For this purpose, the second element 22 preferably has one or more translucent color layers and / or photochromic layers, which are structured accordingly to form the one or more first partial regions 221 and second partial regions 222.

[0134] The first partial regions 211 of the first element and the first partial regions 221 of the second element 22 overlap at least partially perpendicular to the x / y plane spanned by the first main surface, so that the color impression resulting from transmitted light viewing can be adjusted by means of the second element 22, preferably without thereby impairing the color impression which is shown in reflected light viewing from the front and / or back.

[0135] Thus, preferably in the one or more first regions 41, first partial regions 211 of the first element 21 and first partial regions 221 of the second element 22 are arranged in register with one another when viewed perpendicular to the plane spanned by the first main surface 201 in such a way that in the respective region 41 a first colored feature 31 becomes visible in transmitted light, which is not visible in particular when viewed in reflected light from the front or back: For example, in the embodiment according to Fig. 1c In transmitted light, the first feature 31 is a colored lettering "KINEGRAM" in a first area 41, for example, in red, and the first feature 31 in another first area 41 is a schematic sun of the same color. These motifs of the features 31 thus appear to the viewer in transmitted light, for example, in red, against an opaque, dark background.

[0136] In the embodiment according to Fig. 1c First partial areas 211 are provided only in the first areas 41 and the entire remaining area of the see-through security element 2 is fully covered with a second partial area 212. The see-through security element 2 thus appears metallic silver when viewed from the front as well as from the back, for example, as well as in Fig. 1a und Fig. 1b The motifs (sailboat, water, denomination, currency symbol) are generated by corresponding optically variable relief structures, as explained above. When viewed through transmitted light, the viewer sees the Fig. 1c illustrated colored features 31 in the form of the motifs presented above against a solid dark background.

[0137] In the first area 41, preferably, as in Fig. 1d As indicated, the first partial regions 211 and the first partial regions 221 are positioned relative to one another such that, when viewed perpendicular to the plane spanned by the first main surface 201, the first partial regions 221 overlap congruently with a respectively assigned first partial region 211. This ensures that the color of the one or more first partial regions 221 essentially only has an optical effect when viewed in "transmitted light" but not when viewed in "incident light" (from both the front and back). Furthermore, the first partial regions 211 and 221 in the first regions 41 preferably have a dimension of less than 500 µm, preferably less than 300 µm, in particular less than 150 µm, in at least one lateral direction and are thus preferably designed as thin lines or raster elements.This also ensures that the optical effect of the first partial areas 211 and 221 is essentially only visible in transmitted light and thus corresponds to the effect shown in the figures. Fig. 1a bis Fig. 1c clarified incident light / transmitted light effect is achieved.

[0138] Furthermore, it is also possible that the see-through security element 2 outside the one or more first regions 31 is not formed over its entire surface by a second partial region 212, but also has first partial regions 211 there.

[0139] This is exemplified in Fig. 2 shown: Fig. 2 shows the security element 2. As illustrated there, outside the areas 41 in which the colored security features 31 become visible when viewed in transmitted light, first partial areas 211 are also provided, which, when viewed in transmitted light, make visible, in particular, colorless, recognizable motifs, here for example, waterlines and the stylized outline of a sailboat as a further feature 35. This see-through security element 2 thus has, for example, a partial metallization designed for viewing in reflection, which in this example is in the form of the sailboat and water waves. In the sail and in the hull of the boat, additional security features 31 are further provided, as already explained above, which only appear as colored security features 31 when viewed in transmitted light.

[0140] In this exemplary embodiment, it is also possible for relief structures, in particular diffractive and / or refractive microstructures, to be provided in the second partial regions 212, and thus, for example, for a Fresnel-like microstructure to be provided in the second partial region 212 forming the hull of the sailboat, creating the illusion of a hull protruding from the plane of the see-through security element 2. Non-achromatically diffractive or reflective microstructures that imitate the fluttering of the sails can be provided in the second partial regions 212 forming the sails of the boat.

[0141] It is further advantageous if the see-through security element 2, when viewed in incident light, appears in a different color than when viewed in transmitted light. For example, if red is selected as the color for features 31, the motifs of features 33 preferably appear shiny silver or in a color other than red.

[0142] Furthermore, it is preferred if the features 31 have several different colors and / or have colorless sub-areas in addition to "colored sub-areas". Fig. 3 Such a design of the see-through security element 2 is indicated, which, when viewed in transmitted light, generates as first feature 31 the lettering "KINEGRAM" in red, and as first feature 31 a stylized sun in "blue" (indicated here by dotted lines).

[0143] Such effects can be achieved by forming color filters in the one or more first partial regions 221 of the second element 22, which color filters are assigned to the different colors and are provided in precise register with the different colored partial motifs or motifs of the first feature 31 or the first features 31. Furthermore, it is possible here for first partial regions 211 of the first element 21 to be provided in the first regions 41, which do not overlap with associated first partial regions 221 of the second element 22, but rather overlap with the at least one second partial region 222 of the second element 22. This makes it possible for the first features 31 to have, in addition to colored partial regions or partial motifs, also colorless / white-appearing partial regions or partial motifs, thus further improving the appearance of the one or more first features 31.

[0144] Furthermore, it is advantageous that in the first regions 41, the one or more first subregions 211 of the first element 21 are each enclosed by at least 80% of the area, preferably more than 90% of the area, and in particular completely, by the at least one second subregion 212 of the first element 21 and / or that in the first regions 41, the one or more first subregions 221 of the second element 22 are each enclosed by at least 80% of the area, preferably more than 90% of the area, and in particular completely, by the at least one second subregion 222 of the second element 22. Studies have shown that such a design of the first and second subregions 211, 212, 221, 222 further improves the concealment of the first features 31 when viewed in incident light.

[0145] As already explained above, the one or more first partial regions 211, 221 are further preferably designed in the form of lines and / or grid points which have a width or diameter of less than 500 µm, preferably less than 300 µm, particularly preferably less than 150 µm.

[0146] Furthermore, it is advantageous to make the second partial regions 212 appear as "brilliant" as possible when viewed in reflected light in the first regions 41. To this end, the aim is preferably to achieve the highest possible reflectivity when viewed in reflected light in the partial regions 212, preferably a reflectivity of more than 30%, more preferably more than 50%, more preferably more than 70%.

[0147] As already explained above, reflectivity is understood here as the ratio of the light radiated in the visible wavelength range to the light reflected, diffracted or scattered back, i.e. the "total amount" of light "returning" in the visible wavelength range towards the observer when viewed in incident light.

[0148] In this case, it has proven particularly useful to provide the at least one second subregion 212, in particular the first regions 41, with optically active relief structures, in particular with diffractive relief structures generating a rainbow effect and / or diffractive, light-diffracting, or reflective achromatic relief structures generating achromatic motion effects. These motion effects can be arranged with further, optically variable, effects in the form of a grid or combined in another way. This means that at least one second subregion 212 is divided into a plurality of zones, in each of which a relief structure associated with one of the effects is molded into a reflective layer provided in the at least one second subregion 212.

[0149] Furthermore, it has been shown that a concealment of the first features 31 in incident light viewing is further improved in that one or more of the first partial regions 211 and the one or more first partial regions 221 each have a dimension between 5µm and 300µm, preferably between 10µm and 200µm, more preferably between 15µm and 150µm, at least in one lateral direction.

[0150] Preferably, the one or more first subregions 211 and 221, respectively, as also in Fig. 8 indicated, formed in the form of a fine, continuous line.

[0151] Preferably, the width ΔL of at least 70%, more preferably at least 90% of the first partial regions 211 and 221 in the region 41 is less than 300 µm.

[0152] The line width ΔL in the first region 41 is preferably between 5 µm and 300 µm, more preferably between 10 µm and 200 µm, more preferably between 15 µm and 150 µm.

[0153] Furthermore, it is also possible here that, with such a configuration of the one or more first regions 211 and 221 in the form of fine lines, these lines can also be substructured, for example in the form of lines or dots, which are then "grouped" into corresponding lines, which ultimately form visible first features 31 when viewed in transmitted light.

[0154] In addition to such a design of the one or more first subregions 211 and / or 221 in the form of lines, it is also advantageous to design the first subregions 211 and 221 in the form of grid points, which are arranged according to a one- or two-dimensional grid in the respective first region 41. The individual grid points can have any desired shape, for example, in plan view, circular disk-shaped, square, rectangular, but also a complex structure such as an alphanumeric character. The grid points preferably have widths of between 5 µm and 300 µm, preferably between 10 µm and 200 µm, more preferably between 15 µm and 150 µm in one, more preferably in both lateral directions.In the simplest case, when a grid point is designed as a "circular disk", the diameter of this circular disk when viewed perpendicular to the plane spanned by the first main surface 201 is between 5 µm and 300 µm, preferably between 10 µm and 200 µm, more preferably between 15 µm and 150 µm.

[0155] Such a configuration can provide a "flat" colored first feature 31 when viewed in transmitted light. The individual "raster points" are arranged relative to the grid in such a way that the human observer perceives an "integral" effect as much as possible, and a perceptible "surface shape" appears to the observer, which is preferably delimited by the outline of the area in which the raster points are provided according to the grid, and whose brightness is determined by the respective local spacing and size of the raster points.

[0156] Preferably, the spacing of the grid points of the grid and / or the period of the grid is in the range between 5 µm and 300 µm, preferably between 10 µm and 200 µm, more preferably between 15 µm and 150 µm.

[0157] Furthermore, it is advantageous if the at least one second partial region 212 of the first element 21 completely encloses the one or more first partial regions 211 of the first region 41, and further also completely encloses the respective first region 41 of the see-through security element 2, when viewed perpendicular to the plane spanned by the first main surface 201.

[0158] Furthermore, it is advantageous that the first partial regions 211 provided in the first region 41 are surrounded in all lateral directions at least at a distance d from the at least one second partial region 212. This is the case, for example, in Fig. 9 clarifies: Thus, the second partial area 212 extends from the respective first partial areas 211 at least by the distance d.

[0159] Preferably, the distance d is chosen to be greater than 0.5 mm, more preferably greater than 0.8 mm, and more preferably greater than 1 mm.

[0160] Furthermore, it is advantageous that the at least one second partial region 212 extends from the first region 41 at least by the distance d, when viewed perpendicular to the plane spanned by the first main surface.

[0161] If, for example, in Fig. 10 As illustrated, the first region 41 of the see-through security element is formed by the smallest possible rectangular region, in which each edge of the rectangular region adjoins the first feature 31, when viewed perpendicular to the plane spanned by the first main surface 201, the second partial region 212 completely encloses this "rectangle" in a strip having a width d.

[0162] As in Fig. 10 As illustrated in FIG. 1, the outline contours of the first feature 31 are defined by the lateral arrangement of the first partial regions 211. This applies accordingly if the first partial regions 211 are designed in the form of raster points. As in Fig. 10 As illustrated, for the first feature 31, which is in the form of the letter sequence "KINGEGRAM", this definition of the first area 41 results in the Fig. 10 The shape of the area 41 shown is in the form of a rectangle with a length b and a width a.

[0163] As in Fig. 10 As illustrated, the rectangle can also be "rotated" if this results in a smaller area. In the case of Fig. 10 , the corresponding smallest rectangle is the rectangle arranged below, which is diagonally adjusted to the lettering, and is used as the smallest rectangle for the definition of area 41.

[0164] Investigations have shown that with such a configuration, the detectability of the first feature 31 is further improved, as well as the "obfuscation" of the first feature 31 when viewed in reflected light. Because the first partial areas 211 are surrounded by a correspondingly large area by a second partial area 212, the optical contrast is increased for the viewer of the see-through security element 2 in transmitted light, thus simplifying the reliable inspection of the properties by the viewer.

[0165] Furthermore, it has proven advantageous if the area proportion F of the first partial regions 211 provided in the first region 41 to the total area of the region 41 is less than 20%, more preferably less than 10%, more preferably less than 5%.

[0166] The first area used for this calculation is preferably as above based on the Figur 10 explained, ie defined by the smallest possible rectangle enclosing the first sub-regions 211, which form the first feature 31. The area proportion F is thus determined from the total sum of the first sub-regions 211 in the region 41 to the total sum of the first sub-regions 211 and the second sub-regions 212 in the region 41.

[0167] A preferred embodiment provides that the see-through security element has a first element 21, which has one or more transparent first partial regions 211 and at least one reflective second partial region 212, and a second element 22, which has one or more first partial regions 221, each of which forms a color filter in transmission that is matched to a respective assigned color, and at least one second partial region 222, which is colorless, in particular colorlessly transparent, or forms a color filter in transmission and / or reflection that is matched to a color that is not assigned to any of the one or more first partial regions 221 of the second element 22, wherein the first partial regions 211 of the first element 21 and the first partial regions 221 of the second element 22 at least partially overlap when viewed perpendicular to the plane spanned by the first main surface.

[0168] The transparent first partial regions 211, together with the reflective second partial regions 212, create a grayscale image that appears silver metallic when viewed in incident light from the front and back. The colored first partial regions 221 of the second element 22 are recognizable as single- or multi-colored when viewed in transmitted light.

[0169] Fig. 16 shows this as an example using a flower motif. The rasterization for generating the grayscale image is shown in the enlarged section. The reflective second partial areas 212 are represented here by dark areas, the transparent first partial areas 211 are represented by light areas. In the transparent first partial areas 211, the color layer 221 structured by means of the negative photoresist in register with the reflective second partial areas 212 is present. Optionally, two or more differently colored photoresists can be used overlapping the partial areas 211, e.g. a yellow colored photoresist in the area of the entire flower and in the round center (pistil) of the flower, an additional red colored photoresist on top of the yellow colored photoresist (see Fig. 18a and Fig. 18b ). Since the two colored photoresists can be translucent, i.e. transparent or semi-transparent, photoresists, a mixed color of yellow and red is created in the round center (pistil) of the flower in the partial areas 211 when viewed in transmitted light. The petals of the flower appear yellow in the partial areas 211 when viewed in transmitted light. As a result, the flower appears two-colored in the partial areas 211 when viewed in transmitted light. Alternatively, the two or more photoresists can also be applied in such a way that they do not overlap or only overlap in partial areas. Different colored photoresists are arranged in different partial areas 211. A reflective, opaque frame made up of the partial areas 212 around the flower can be used to compensate for any printing tolerances during the partial application of the negative photoresist.

[0170] In order that the color in the transparent first partial regions 211 is not visible or is as invisible as possible when viewed in incident light, the transparent first partial regions 211 preferably comprise less than 30% of the area of the first element 21, more preferably less than 20% of the area of the first element 21, and particularly preferably less than 10% of the area of the first element 21 in at least 50% of the area of the grayscale image. Further preferably, the transparent first partial regions 211 comprise less than 30% of the area of the first element 21, more preferably less than 20% of the area of the first element 21, and particularly preferably less than 10% of the area of the first element 21 in at least 70% of the area of the grayscale image.

[0171] Further preferably, brilliant optically variable effects, in particular motion effects, are present in the subregions 212 in the grayscale image of the first element 21. Diffractive grating structures with a line count of 500 lines / mm to 2000 lines / mm, and more preferably 600 lines / mm to 1500 lines / mm, and / or refractive micromirrors and / or refractive structures with predominantly achromatic optical effects can be used. Such brilliant effects conceal the color in the subregions 211, which is in register with the metallization in the subregions 212, particularly well.

[0172] A particular advantage of grayscale image formats is the ability to avoid abrupt brightness transitions. This makes brightness transitions more difficult to detect in reflected light, while the image information remains clearly visible in transmitted light.

[0173] Furthermore, it is also possible that one or more first partial regions 221 of the second element 22 are also provided outside the first regions 41. This is exemplified in Fig.4a und Fig. 4b shown: Fig. 4a shows such a see-through security element 2 in reflected light view from the front and Fig. 4b in transmitted light viewing.

[0174] In this exemplary embodiment, the feature 31 already explained above is visible in transmitted light, and the features 33 and 34 already explained above are visible in reflected light. Furthermore, colored features 32 are visible in transmitted light, each of which is configured as part of a "cloud." These features 32 are formed by correspondingly shaped first partial regions 221 of the second element 22, which are arranged in a correspondingly overlapping manner within a large-area first partial region 211 of the first element 21. Preferably, these first colored features 32 are also visible in reflected light, as shown in Fig. 4a indicated.

[0175] Preferably, the first partial areas 221, which form the features 32, are arranged in such a way as to be precisely registered with a first partial area 211 of the first element that the colored features 32 directly adjoin a third feature visible from the front and the back when viewed in incident light and thus - as in Fig. 5a und 5b represented - for example, directly adjacent to feature 33 and in particular its sub-motifs "sail".

[0176] Preferably, the security element 2 has one or more second areas 42 in which, as in Fig. 1d clarifies, at least one of the first partial regions 221 of the second element partially directly borders a second partial region 212, when viewed perpendicular to the plane spanned by the first main surface 201. Thus, for example, the partial region 221 formed in the shape of a "cloud" overlaps with a first partial region 211 of the first element, which is formed, for example, in the "negative form" of the sailboat, such that this partial region 221 partially directly borders a second partial region 212 adjacent to this first partial region 211. For example, by the right edge of the "cloud" or the left edge of the "cloud", as in Fig. 5a und Fig. 5b clarifies, directly adjacent to the second partial area 212, which is designed in the form of a "sail".

[0177] Preferably, as in Fig. 5b As shown, the respective overlapping first and second partial areas 211 and 221 have a different shape or form different motifs, in particular complementary motifs.

[0178] It is further possible that not only a first sub-area 221 is provided within a first sub-area 211, but also two or more such sub-areas, which in particular each form color filters that are matched to different colors.

[0179] This will be explained below using Fig. 5c und Fig. 5d clarifies: Fig. 5c shows a view of a see-through security element 2 when viewed in incident light from the front side and Fig. 5d a transmitted light view of this see-through security element 2. As shown in the figures Fig. 5c und Fig. 5d As indicated, the feature 32 is formed here by a first partial region 221, which is in the form of a cloud and appears in the color "blue" when viewed in transmitted light, and a first partial region 221 arranged in register with it, which is in the form of half a "sun" and appears in the color "yellow" when viewed in transmitted light.

[0180] The fact that the two first partial areas 221 are directly adjacent to one another ensures that no mixed colors are created in the overlapping area, which would significantly impair the viewing impression.

[0181] This perfect registration between the two colors, without a mixed color at the border between the two colors, represents a very high hurdle for counterfeiters, further increasing counterfeit security. A mixed color would arise at the border if colors overlap there, thus preventing perfect registration.

[0182] Fig. 6a und 6b illustrate a see-through security element 2, in which the first partial areas 221, which form the features 32, are formed in the form of lines and which, as already Fig. 4a bis 5b explained, border precisely on a second area 212. These lines are formed here in the form of a stylized cloud.

[0183] Fig. 6a illustrates a top view of the security element 2 when viewed from the front in incident light, and Fig. 6b when viewed through transmitted light. Features 32 appear blue when viewed through transmitted light.

[0184] It is also possible that the first partial areas 221 not only adjoin the second partial area 212 seamlessly, but, as in Fig. 7a shown, a gap of width s is provided between the first partial region 221 and the second partial region 212. The width of the gap s is preferably less than 500 µm, preferably less than 300 µm, more preferably less than 150 µm and in particular less than 50 µm. This ensures that, on the one hand, there is no overlap and no influence on the optical effect of the second partial region 212 when viewed in reflected light, and on the other hand, the human observer can still very easily assess the register accuracy of the two elements and, accordingly, a forgery can be easily checked.

[0185] It is also possible that the first partial region 221 and the second partial region 212 each have an overlap t of not more than 100 µm, preferably not more than 50 µm, more preferably not more than 10 µm. This is in Fig. 7b clarified.

[0186] Investigations have shown that with such a small overlap, corresponding optical changes in the second partial area 212 are not yet, or hardly, perceptible when viewed in incident light.

[0187] A further preferred embodiment provides that, in particular, a security document, preferably the security document 1 according to Fig. 1 , has two or more see-through security elements.

[0188] A first see-through security element preferably comprises a first element 21 and a second element 22. A second see-through security element preferably comprises a first element 21 and a second element 22.

[0189] If the first see-through security element has a first element 21 and a second element 22, the second see-through security element can only have a first element 21.

[0190] If the second see-through security element has a first element 21 and a second element 22, the first see-through security element can only have a first element 21.

[0191] However, it can also be provided that the first see-through security element has a first element 21 and a second element 22 and the second see-through security element has a first element 21 and a second element 22.

[0192] The first see-through security element has a first element 21 which has one or more transparent first partial regions 211 and one or more reflective second partial regions 212, wherein the first see-through security element has a second element 22 which has one or more first partial regions 221 which each form a color filter in transmission that is matched to a respective assigned color, and one or more second partial regions 222 which are colorless, in particular colorlessly transparent, or which form a color filter in transmission and / or reflection that is matched to a color that is not assigned to any of the one or more first partial regions 221 of the second element 22, wherein the first partial regions 211 of the first element 21 and the first partial regions 221 of the second element 22 at least partially overlap when viewed perpendicular to the plane spanned by the first main surface.

[0193] The second see-through security element has a first element 21, which has one or more transparent first partial areas 211 and one or more reflective second partial areas 212, wherein the second see-through security element has a second element 22, which has one or more first partial areas 221, each of which forms a color filter in transmission that is matched to a respective assigned color, and one or more second partial areas 222, which are colorless, in particular colorlessly transparent, or form a color filter in transmission and / or reflection that is matched to a color that is not assigned to any of the one or more first partial areas 221 of the second element 22,wherein the first partial regions 211 of the first element 21 and the first partial regions 221 of the second element 22 at least partially overlap when viewed perpendicular to the plane spanned by the first main surface.

[0194] Fig. 17a shows a schematic sectional view of the first and second see-through security elements 2a, 2b, which are arranged in a transparent region, in particular a transparent window region, on opposite sides of a substrate 10 of a security document, in particular a banknote made of a polymer substrate, and spaced apart from one another by a distance h. The first see-through security element 2a functions as a luminescent layer, and the second see-through security element 2b as a mask layer.

[0195] Preferably, the first element 21 and the second element 22 are arranged in the second see-through security element 2b and only the first element 21 is arranged in the first see-through security element.

[0196] The first element 21 of the first see-through security element 2a thus has first subregions 211 and second subregions 212 arranged in the form of moiré information. For this purpose, the second element 22 of the first see-through security element 2a, i.e., a structured color layer, is arranged in the register.

[0197] The first element of the second see-through security element 2b thus also has first subregions 211 and second subregions 212, with the first subregions 211 creating transparent openings and the second subregions 212 creating opaque (reflective) regions. For this purpose, the first subregions 221 and second subregions 222 of the second element, i.e., a structured color layer in the first subregions 221, are arranged in register.

[0198] Preferably, the structured color layer is arranged only in one see-through security element, preferably in the second see-through security element 2b (mask layer).

[0199] In Fig. 17a The second see-through security element 2b is shown viewed in transmitted light from the visible side. The light strikes the first see-through security element 2a, i.e., the luminescent layer—e.g., a protective layer of a security element—and transmits the light to the second elements 22, for example, in the form of a structured color layer, and to the first elements 21 in the form of moiré information. The light penetrates the substrate 10 and the second see-through security element 2b (mask layer) through the transparent openings, thereby creating the desired effect, e.g., moiré enlargements and / or motion effects.

[0200] Fig. 17b shows in a schematic plan view the second see-through security element 2b (mask layer), the first see-through security element 2a (luminescent layer) and the visible image information 36.

[0201] In the present example, the second see-through security element 2b (mask layer) is designed as a line grid, with the first elements in the form of a line grid and the second elements in the form of a structured color layer. The first see-through security element 2a (luminescent layer) in the present example has first elements in the form of moiré information. The image information 36 visible in the present example when viewed in transmitted light corresponds to the letter combination "OK."

[0202] In In the second see-through security element 2b (mask layer), a dot grid is also possible instead of the line grid.

[0203] The moiré information in the first see-through security element can, for example, be in the form of a microimage grid, with the microimages arranged according to a periodic grid, which are made visible to the human observer as large images through the so-called moiré magnification effect. If the banknote is tilted in transmitted light or the viewing angle is otherwise changed, the visible large images appear to move.

[0204] Preferably, one of the two see-through security elements 2a, 2b or both has, in register with the (reflective) second partial areas 212 of the first element 21, the (colored) first partial areas 221 of the second element 22, as in Fig. 17c shown schematically. This makes the movement effect appear single- or multi-colored in transmitted light.

[0205] Possible methods for producing a see-through security element and in particular the see-through security elements 2, 2a, 2b according to the preceding embodiments will now be described below with reference to the Figuren 11a bis 15i clarified: First, as already described above, a substrate is produced which comprises the carrier layer 23 and the one or more lacquer layers 24 optionally applied thereto.

[0206] On this substrate, which preferably has a replication layer as a lacquer layer 24, into which microstructures are molded by means of thermal replication and / or UV replication, an opaque metal layer 60 is first deposited over the entire surface. Fig. 11a shows such a substrate. The metal layer 60 can be made of aluminum, silver, chromium, or copper, for example. This can be achieved, for example, by thermal evaporation in a vacuum.

[0207] Furthermore, it is also possible to apply, in addition to the layer 60, one or more further layers of the above-described layers, which can be provided for forming the first element 21.

[0208] Then, as in Fig. 11b As shown, layer 60 is partially removed. This can be done, for example, by printing an etching resist and subsequent etching, or by means of a washing process. If a washing process is used, a washcoat is printed in the corresponding areas before layer 60 is applied. This washcoat is then dissolved or removed in a washing process together with the overlying areas of layer 60 after layer 60 has been applied.

[0209] This process can be repeated several times with the application of additional layers. Furthermore, it is also possible to apply one or more of the layers mentioned above for the first element 21 partially and in a patterned manner, particularly in register with layer 60.

[0210] After the first element 21 has been produced by carrying out such processes, as shown in Fig. 11c As illustrated, a photoresist layer 70 made of a negative photoresist is applied over the entire surface.

[0211] The first element 21 consists, as already explained above, of the one or more first sub-areas 211 and the one or more second sub-areas 212. As in the Fig. 11c As illustrated in the exemplary embodiment shown, the one or more layers of the first element 21 are provided in the partial regions 212, but not in the partial regions 211. In the simplest case, the first element 21 thus consists of the metal layer 60, which is provided in the partial regions 212 after the structuring process has been carried out, but is not provided in the partial regions 211.

[0212] The photoresist is preferably a negative photoresist which is colored accordingly in order to provide a color filter in transmission which is matched to a given color, for example "blue".

[0213] A negative photoresist is characterized by the fact that, upon sufficient exposure to a suitable wavelength, e.g., UV radiation, this resist hardens, making the exposed areas insoluble in a specific solvent, e.g., acidic or basic aqueous solutions. Thus, masked exposure allows for the creation of colored areas of defined shape and size.

[0214] The main components of an epoxy resin-based negative photoresist are generally low molecular weight organic compounds that have more than one epoxy group per molecule.

[0215] Epoxy resins based on bisphenol A, epoxidized phenol novolac, resorcinol glycidyl ether and cycloaliphatic resins are preferred as resin components for photoresist production.

[0216] In combination with a crosslinker (hardener), the resin / hardener system forms a macromolecular network through polymerization of the epoxy group. Various hardeners can be used, differentiated by the ring-opening reaction of the oxirane groups. Acid anhydrides, amines, or phenol-containing compounds are preferred, or triarylsulfonium salts are used as the photoactive component.

[0217] Furthermore, catalysts such as Lewis bases and acids are preferably used. The hardener is incorporated into the three-dimensional network structure. In the case of a basic accelerator, the catalyst promotes network formation via ester bridges.

[0218] g-Butyrolactone is preferably used as a solvent in the printing ink of such epoxy resin-based photoresists.

[0219] Furthermore, additives such as long-chain epoxy resins are preferably used to serve as adhesion promoters, reactive diluents or to add or reduce viscosity.

[0220] For example, the SU-8 epoxy novolac photoresist based on bisphenol A, triarylsulfonyl hexafluoroantimonate, and g-butyrolactone (sold, for example, by MicroChem. Corporation) is used as a negative photoresist. This photoresist is colored with Orasol dyes or Microlith color pigments.

[0221] Water-based negative photoresists can, for example, be colored with Luconyl.

[0222] The photoresist layer 70 is applied, for example, over the entire surface of the first element 21 by means of gravure printing, as shown in Fig. 11c clarified.

[0223] Furthermore, it is also possible for one or more additional layers to be provided between the first element 21 and the photoresist layer 70. However, the total thickness of such layers is preferably no more than 15 µm, more preferably no more than 5 µm.

[0224] Studies have shown that if the thicknesses are exceeded, good register accuracy can no longer be achieved and negative optical effects also occur.

[0225] These intermediate layers can be, for example, additional resist layers to protect in particular the metal layer 60 in further process steps, an adhesion-promoting layer for improved bonding of the photoresist, replication layers, a full-area or partial HRI layer, a SiOx layer or a further photostructurable layer which, however, has no coloring.

[0226] Then, as in Fig. 11d As illustrated, an exposure of the photoresist layer 70 with a suitable wavelength is carried out by the first element 21, for example by means of UV radiation 80. In this case, in particular the partial metal layer 60 serves as a mask for the exposure.

[0227] Since the photoresist is a negative photoresist, only the exposed parts of the photoresist layer 70 remain in a washing process carried out after exposure, as in Fig. 11e shown. The remaining partial areas of the photoresist layer 70, due to their properties, form first partial areas 221 of a second element 22, which are formed in perfect register with the first partial areas 211 in the see-through security element 2. Subsequently, an adhesive and / or adhesion-promoting layer and / or protective layer is optionally applied. Fig. 11f It is shown here that in a further step the adhesive layer 25 is applied over the entire surface, for example by means of gravure printing.

[0228] Furthermore, it is also possible to apply the photoresist layer 70 not over the entire surface, but in sections. This makes it possible to compensate for tolerances in the partial photoresist layer applied, for example, by gravure printing, and to form further regions in which a first partial region 211 does not overlap, or only partially overlaps, with a first partial region 221.

[0229] First, as shown in the figures Fig. 12a and Fig. 12b presented in the same way as above using Fig. 11a and 11b clarifies, proceeded. In this regard, reference is made to the above explanations.

[0230] Then, as in Fig. 12c shown, the photoresist 70 is printed only in certain areas, in particular by means of gravure printing and then, as in Fig. 12d By developing and subsequently washing off the unexposed photoresist, the film is then Fig. 12e shown, a perfect register is achieved in one area between a first sub-area 211 and a first sub-area 221.

[0231] Furthermore, it is also possible to form first sub-areas 221 which only partially overlap with a first sub-area 211.

[0232] Then, as in Fig. 12f shown, optionally further layers, in particular the adhesive layer 25, are applied.

[0233] Furthermore, it is also possible to use the procedure according to Fig. 12a bis Fig. 12f to print differently colored photoresist layers next to each other.

[0234] In this case, the printing is preferably carried out in such a way that the layer boundaries of the partial photoresist layer 70 and / or the differently colored photoresist layers 70 lie in the second partial regions 212. This provides the advantage that the insufficient registration of the printing process used to apply this layer is compensated for by the subsequent exposure process.

[0235] This makes it possible, as already explained above, to produce first partial areas 221 formed in first partial areas 211 with perfect register accuracy, in which transmissive color filters are matched to different colors.

[0236] Another manufacturing process is now being developed using Fig. 13a bis 13h This procedure is first carried out as already shown in Fig. 12a bis 12c This is shown in the figures Fig. 13a bis Fig. 13c clarified.

[0237] As in Fig. 13c As shown, a negatively colored photoresist is applied here in such a way that it covers not only one or more first partial regions 211, but also a second partial region 212 surrounding them. The photoresist layer 70 is applied here, for example, by means of gravure printing. This application makes it possible to compensate for the considerable tolerances of a gravure printing process, which are in the range of + / - 0.1 mm transverse to the direction of travel of the printing process.

[0238] Then, as in Fig. 13d As illustrated, a blocking layer 75 is partially printed, for example by means of gravure printing.

[0239] The blocking layer 75 is a layer that is colored and simultaneously blocks the exposure of the photoresist to the radiation used. Preferably, the blocking layer 75 is a UV blocking layer. The blocking layer 75 blocks the incident UV radiation at least in a portion of the UV wavelength range used for exposure, such that a maximum of 25%, more preferably a maximum of 15%, of the incident intensity passes through the blocking layer 75.

[0240] The UV wavelength range is preferably understood to be a range between 250 nm and 405 nm.

[0241] The blocking layer 75 is preferably colored, as already explained above, preferably in a different color than the negative photoresist 70. The blocking layer 75 is preferably colored such that it forms a color filter in transmission which is matched to a color which is different from that of the colored photoresist layer 70.

[0242] Furthermore, it is also possible for such a blocking layer to be incorporated into the layer structure of the layers applied above, for example the carrier layer 23 or the one or more lacquer layers 24.

[0243] In a next optional step, as in Fig. 13e As shown, one or more additional photoresist layers 70 can be printed, which are preferably formed differently from the already printed photoresist layer 70, as already explained above. Here, too, the partial coating with the one or more photoresist layers 70 is preferably carried out such that the photoresist layers 70 partially overlap the blocking layer and / or the first partial regions 212 in order to "absorb" the register fluctuation of the printing process, as already explained above.

[0244] Then, as in Fig. 13f shown, a corresponding exposure. Subsequently, the unexposed areas of the photoresist layer 70 are washed off, thereby achieving perfect registration between the differently colored areas and the first partial areas 211.

[0245] As already mentioned above, additional intermediate layers, e.g., barrier layers and / or adhesion promoter layers and / or stabilizing layers, can be introduced. In particular, non-colored negative photoresist layers can be used as patternable barrier layers. These then prevent, for example, unwanted diffusion of the dye from the colored negative photoresist into the blocking layer. This barrier layer can also prevent, for example, the dissolution of the metal layer 16, thus expanding the range of solvents that can be used in the washing process and / or extending the possible exposure time.

[0246] Afterwards, as in Fig. 13h As illustrated, one or more further layers, for example the adhesive layer 25, are applied.

[0247] The blocking layer 75, like the colored photoresist layer 70, can be partially applied using digital printing, for example, inkjet printing. This allows for the creation of individual markings for individual see-through security elements.

[0248] A colored photoresist layer 70 can also be applied over the entire surface and exposed only partially. This exposure can be performed, for example, via a mask and / or by means of controllable UV light-emitting diodes.

[0249] Furthermore, for the production of a see-through security element 2 as described below with reference to Fig. 14a bis Fig. 14e First, as already shown above with reference to the figures Fig. 11a and Fig. 11b See Fig. 14a and Fig. 14b . In this regard, reference is made to the above comments.

[0250] Then, as in Fig. 14c shown, a photochromic layer 71 is applied over the entire surface instead of a photoresist.

[0251] A photochromic layer is defined as a layer that permanently changes its color upon exposure to radiation of a suitable wavelength, or permanently maintains its color upon exposure to radiation of a suitable wavelength. The suitable wavelength is, in particular, UV radiation.

[0252] Instead of applying the photochromic layer 71 over the entire surface, this layer can be applied in the same way as described above with reference to the figures Fig. 12 and Fig. 13 described - can also be printed only in certain areas or different photochromic layers 71 can be printed next to each other, which change their colours in different ways when irradiated or receive different colours when irradiated.

[0253] Subsequently, exposure takes place, preferably using UV radiation 80. This is in Fig. 14d shown.

[0254] However, after exposure, the exposed portion of the photochromic layer is not washed away (as described in the previously described processes with respect to the photoresist layer 70). Rather, the exposed photochromic layer 71 remains completely in the layer stack. Irradiation with UV radiation 80 causes the photochromic layer 71 to change from transparent in the visible wavelength range to colored in the visible wavelength range, preferably colored in such a way that the photochromic layer 71 forms a color filter in transmission in these ranges, which is matched to a predefined color.

[0255] Furthermore, it is also possible for the photochromic layer 71 to be already colored and merely change color in the irradiated areas. In this case, the photochromic layer 71 is preferably formulated such that, as described above, a corresponding color filter is formed in transmission in the exposed areas, and a different color filter is formed in reflection and / or transmission in the unexposed areas.

[0256] After exposure, a second element 22 is formed by the photochromic layer 21, which second element 22 forms a color filter in transmission in first partial areas 221, which is matched to an assigned color, and in second partial areas 222 is colorless / transparent or forms a color filter in reflection and / or transmission, which is matched to a color that is different from the color to which the color filters of the first partial areas 221 are matched.

[0257] Then, as in Fig. 14f shown, optionally the application of one or more further layers, for example the adhesive layer 25.

[0258] Furthermore, it is also possible for the see-through security element to additionally comprise a third element, which is provided below the second element. A preferred manufacturing method for producing such a see-through security element is described below with reference to the figures. Fig. 15a bis Fig. 15i described: First, as shown in the figures Fig. 15a und Fig. 15b presented in the same way as above using Fig. 11a and Fig. 11b clarifies, proceeded. In this regard, reference is made to the above explanations.

[0259] Then, as in Fig. 15c As shown, the photoresist 70 is preferably printed only in certain areas, in particular by means of gravure printing. However, instead of a photoresist, a colored resist can also be printed. As shown in Fig. 12c As illustrated, the photoresist 70 overlaps at least a first partial region of the first element, at least in some areas. Furthermore, it is also possible for the photoresist 70 to overlap the second partial region of the first element 21, at least in some areas.

[0260] Then, as in Fig. 12d shown, an optional intermediate layer 26 and one or more layers 27 are applied.

[0261] The optional intermediate layer 26 preferably consists of a transparent lacquer layer, in particular a transparent layer with a layer thickness of preferably less than 5 µm. The optional intermediate layer 26 is preferably a replication layer into which microstructures are molded by means of thermal replication and / or UV replication.

[0262] One or more layers 27 are then applied to the intermediate layer 26, by means of which the third element is then produced in the following processing steps. Layer 27 is preferably an opaque metal layer, which, like the metal layer 60 according to Fig.11a trained. In this regard, reference is made to the previous explanations.

[0263] It is also advantageous if the metal layer 60 and the layer 27 consist of different metals, preferably of different metals with different inherent colors, such as aluminum on the one hand and copper on the other.

[0264] Then, as in Fig.15e shown, a photoresist layer 28 is applied to the layer 27. The photoresist layer 28 can be applied like the photoresist layer 70 according to Fig. 11c trained, so that reference is made to the previous explanations in this regard.

[0265] Then, as in Fig. 15f , an exposure of the photoresist layer 28 with a suitable wavelength is carried out by the first element 21, for example by means of UV radiation 80. Here, the partial metal layer of the first element 21 serves as a mask for the exposure. After the exposure, as in Fig. 15g As shown, the layer 27 in the exposed area is removed by etching or by means of a washing process, and preferably the remaining areas of the photoresist layer 28 are stripped. Here, the illuminated photoresist layer 28 is used as an etching mask or washing mask in the etching and / or washing process.

[0266] An adhesive and / or adhesion promoter layer and / or a protective layer is then applied. In Fig. 15h It is shown here that in a further step the adhesive layer 25 is applied over the entire surface, for example by means of gravure printing.

[0267] As already explained above, a microstructure can be molded into the lacquer layer 24 and the intermediate layer 26, in particular by means of thermal replication and / or UV replication. This is described accordingly in Fig. 15i clarified.

[0268] In The lacquer layer 24 and the intermediate layer 26 can be molded with the same microstructures, but also with different microstructures, in order to achieve different, in particular optically variable effects, for example when viewed from the front and back in incident light. Bezugsziffernliste:

[0269] 1Security document 2See-through security element 2a, 2first / second see-through security element 10Substrate 11Window 12Security feature 21first element 22second element 23Carrier layer 24Lacquer layer 25Adhesive layer 26Intermediate layer 27Layer 28Photoresist layer 31, 32Colored feature 33, 34, 35Feature 36Image information 41First area 42Second area 60Layer 70Photoresist layer 71Photochromic layer 75Blocker layer 80UV radiation 201First main area 202Second main area 211, 221First partial areas 212, 222Second partial areas

Claims

1. See-through security element (2) with a front side formed by a first main surface (201) of the see-through security element (2) and a rear side formed by a second main surface (202) of the see-through security element (2), wherein the see-through security element (2) has at least one first area (41) or at least one first area (41) and at least one second area (42) when viewed perpendicular to the plane spanned by the first main surface (201), wherein the see-through security element (2) has a first element (21) which has one or more transparent first sub-areas (211) and at least one reflective second sub-area (212), wherein the see-through security element (2) has a second element (22) which has one or more first sub-areas (221), each of which forms a colour filter during transmission that is coordinated with a respectively assigned colour, and at least one second sub-area (222), which is designed to be colourless, in particular colourless and transparent, or which forms during transmission and / or reflection a colour filter which is coordinated with a colour that is not assigned to any of the one or more first sub-areas of the second element, wherein the first sub-areas of the first element (21) and the first sub-areas of the second element (22) overlap at least partially when viewed perpendicular to the plane spanned by the first main surface (201), characterised in that, in the first area (41) of the see-through security element (2), the first sub-areas (211) of the first element (21) are assigned to a first group of first sub-areas (211) and to a second group of first sub-areas (211), in that the one or more first sub-areas (211) of the first element (21), which are assigned to the first group, in each case congruently overlap with an assigned first sub-area (221) of the second element (22) when viewed perpendicular to the plane spanned by the first main surface (201), and in that the one or more first sub-areas (211) of the first element (21), which are assigned to the second group, in each case overlap with the at least one second sub-area (222) of the second element (22), wherein, in the first area (41) of the see-through security element (2), the first sub-areas (221) of the second element (22) are assigned to two or more groups of first sub-areas (211), and wherein each of the groups of first sub-areas (211) is assigned a respective colour, wherein the colours assigned to the groups differ, and the colour filter which is formed in the respective first sub-areas (221) is coordinated with the respectively assigned colour.

2. See-through security element (2) according to claim 1, characterised in that, in the first area (41) of the see-through security element (2), one or more first sub-areas (211) of the first element (21) and one or more first sub-areas (221) of the second element (22), when viewed perpendicular to the plane spanned by the first main surface (201), are arranged with register accuracy relative to one another in such a way that a first coloured feature (31) becomes visible in the first area (41) when viewed in transmitted light which is not visible from the front side and rear side in particular when viewed in incident light , and / or in that, in the second area (42) of the see-through security element (2), at least one of the first sub-areas (211) of the first element (21) and at least one of the first sub-areas (221) of the second element (22) when viewed perpendicular to the plane spanned by the first main surface (201) are arranged with register accuracy relative to one another in such a way that a second coloured feature (32) becomes visible in the second area (42) when viewed in transmitted light, which second coloured feature directly adjoins a third feature (33, 34) that is visible from the front side and / or rear side when viewed in incident light.

3. See-through security element (2) according to one of the preceding claims, characterised in that, in the second area (42) of the see-through security element (2), the first sub-areas (221) of second element (22) each have an overlap t of not more than 100 µm, preferably not more than 50 µm, further preferably not more than 10 µm with the at least second sub-area (212) of the first element (21), when viewed perpendicular to the plane spanned by the first main surface (201), and / or in that, in the first and / or second area (41, 42) of the see-through security element (2), the first sub-areas (221) of the second element (22) do not overlap with the at least one second sub-area (212) of the first element (21), when viewed perpendicular to the plane spanned by the first main surface (201), and / or in that, in the first and / or second area (41, 42) of the see-through security element (2), the at least one second sub-area (212) of the first element (21) and the one or more first sub-areas (221) of the second element (22), when viewed perpendicular to the first main surface (201), adjoin one another without overlapping and with a gap of a width S of less than 300 µm, preferably less than 50 µm, further preferably seamlessly.

4. See-through security element (2) according to one of the preceding claims, characterised in that, in the first area (41) of the see-through security element (2), the one or more first sub-areas (211) of the first element (21) are in each case completely surrounded by the at least one second sub-area (212) of the first element (21), and / or in that in the first area (41) of the see-through security element (2), the one or more first sub-areas (221) of the second element (22) are in each case completely surrounded by the at least one second sub-area (222) of the second element (22), and / or in that in the first area (41) of the see-through security element (2), the one or more first sub-areas (211) provided there of the first element (21) and / or the one or more first sub-areas (221) provided there of the second element (22) have a dimension in each case in at least one lateral direction of less than 500 µm, preferably less than 300 µm, and / or in that in the first area (41), the one or more first sub-areas (211) of the first element (21) and the one or more first sub-areas (221) of the second element (22) in each case in at least one lateral direction have a dimension of between 5 µm and 300 µm, preferably between 10 µm and 200 µm, further preferably between 15 µm and 150 µm.

5. See-through security element (2) according to one of the preceding claims, characterised in that, in the first area (41), the one or more first sub-areas (211) of the first element (21) and the one or more first sub-areas (221) of the second element (22) are shaped in each case in the form of a line and / or a raster element, and / or in that in the first and / or second area (41, 42), the one or more first sub-areas (211) of the first element (21) and the one or more first sub-areas (221) of the second element (22) are shaped in each case in the form of a thin, continuous line or sections of a line, the width of which is preferably between 5 µm and 300 µm, preferably between 10 µm and 200 µm, further preferably between 15 µm and 150 µm, and which forms in particular in each case a line of a motif or partial motif of the first or second feature (31, 32) respectively, and / or in that the raster elements are shaped as square, circular disc-shaped, rectangular and / or elliptical raster elements and / or in the form of a raster element which forms an alphanumeric character, in particular a micro print.

6. See-through security element (2) according to one of the preceding claims, characterised in that, in the first area (41), the one or more first sub-areas (211) of the first element are arranged in the form of a one-dimensional or two-dimensional raster, in particular wherein the raster elements of the raster form a motif or partial motif of the first feature (31).

7. See-through security element (2) according to claim 2, characterised in that the raster is a linear raster in which the raster elements follow on from one another in the direction of a line, and / or in that the raster width of the raster and / or the size of the raster dots and / or the spacing of the lines and / or the width of the lines is locally varied in order to locally vary the brightness of the first feature (31), and / or in that the shape of the first feature (31) is determined by the arrangement of the first sub-areas (211) of the first element and / or the first sub-areas (221) of the second element.

8. See-through security element (2) according to claim 2, characterised in that the surface percentage F of the one or more first sub-areas (211) of the first element (21) is less than 20%, preferably less than 10%, further preferably less than 5%, wherein the surface percentage F is the ratio of the surface area of the first area (41) which is occupied by the one or more first sub-areas (211) of the first element (21) to the surface area of the first area which is occupied by the one or more first sub-areas (211) and the at least one second sub-area (212) of the first element (21), and / or in that the first area (41) of the see-through security element (2) is the smallest possible rectangular area in which each edge of the rectangular area adjoins the first feature (31), in each case at at least one place, when viewed perpendicular to the plane spanned by the first main surface (201).

9. See-through security element (2) according to one of the preceding claims, characterised in that the at least one second sub-area (212) of the first element (21) completely surrounds the first area (41) of the see-through security element (2), when viewed perpendicular to the plane spanned by the first main surface (201), and / or in that, starting from the first area (41) of the see-through security element (2), the at least one second sub-area (212) of the first element (21) still extends at least by a distance d, when viewed perpendicular to the plane spanned by the first main surface (201), wherein d is greater than 0.5 mm, preferably greater than 0.8 mm, further preferably greater than 1 mm, and / or in that in the second area (42) of the see-through security element (2), at least one of the first sub-areas (221) of the second element (22) overlaps with a first sub-area (211) of the first element (21), when viewed perpendicular to the plane spanned by the first main surface (201), in such a way that the at least one first sub-area (221) of the second element (22) only partially overlaps the first sub-area (211) of the first element (21), preferably by less than 50%.

10. See-through security element (2) according to one of the preceding claims, characterised in that the at least one first sub-area (221) of the second element (22) forms a motif which is different from the shape of the overlapped first sub-area (211) of the first element (21) and which is visible in the second area (42) as a second colour feature (32) when viewed in transmitted light, and / or in that in the second area (42), a fourth feature (35) determined by the shape of at least one of the first sub-areas (211) of the first element (21) is visible when viewed in transmitted light, and / or in that in the first and / or second area (41, 42), a third feature (33) determined by at least one of the second sub-areas (212) of the first element (21) is visible from the front side when viewed in incident light and / or a third feature (34) determined by at least one of the second sub-areas (212) of the first element (21) is visible from the rear side when viewed in incident light, wherein the third features (33, 34) preferably differ in particular in terms of colour.

11. See-through security element (2) according to one of the preceding claims, characterised in that see-through security element (2) has a third element which has one or more transparent first sub-areas and at least one reflective second sub-area, and in that the second element is arranged in the see-through security element (2) between the first element and the second element.

12. See-through security element (2) according to claim 11, characterised in that, when viewed perpendicular to the plane spanned by the first main surface (201), the first sub-areas (211) of the first element and the first sub-areas of the third element at least partially overlap, preferably overlap congruently, and / or in that, when viewed perpendicular to the plane spanned by the first main surface (201), the at least one second sub-area (211) of the first element and the at least one second sub-area of the third element at least partially overlap, preferably overlap congruently, and / or in that one or more of the first sub-areas of the second element, when viewed perpendicular to the plane spanned by the first main surface, at least partially overlap one or more second areas of the first and / or third element.

13. See-through security element (2) according to one of the preceding claims, characterised in that one or more first sub-areas (211) of the first element (21) and / or third element have a reflectance averaged over the visible wavelength range of more than 10%, further preferably of more than 20%, and / or in that the at least one second sub-area (212) of the first element (21) and / or of the third element is formed by at least one metallic layer (60) or a sequence of layers comprising at least one metallic layer (60) , wherein in particular the at least one metallic layer is not provided in and / or has been removed from the one or more first sub-areas (211) of the first element (21).

14. See-through security element (2) according to one of the preceding claims, characterised in that the at least one second sub-area (212) of the first element (21) and / or the third element has a second relief structure and at least one reflective layer which follows the contour of the second relief structure on at least one main surface (201, 202), preferably on both main surfaces (201, 202), and / or in that the one or more first sub-areas (211) of the first element (21) and / or the third element have a first relief structure.

15. See-through security element (2) according to claim 2, characterised in that, when viewed from the front side and / or rear side in incident light, the second relief structure provides, in particular in the first and / or second area (41, 42), an optically variable third feature (33, 34), in particular a movement effect and / or a colour change effect, and / or in that, when viewed in transmitted light, the second relief structure provides an optically variable feature, in particular in the first and / or second area (42), and / or when viewed in transmitted light, provides an optically variable design element in the first and / or second feature (31, 32).

16. See-through security element (2) according to one of the preceding claims, characterised in that a first group of first sub-areas (221) of the second layer is assigned in each case a first colour, in that a second group of first sub-areas (221) of the second layer is assigned in each case a second colour, in that optionally a third group of first sub-areas (221) of the second layer is assigned in each case a third colour, and / or in that the first, second and third colours are different.

17. Method for producing a see-through security element (2) according to one of the preceding claims, characterised in that one or more colour layers (70, 71) are applied to the first element (21), the solubility and / or colour filter effect of which layers are altered by means of exposure to light, and in that the one or more colour layers (70, 71) are exposed through the first element (21) by using the first element (21) as an exposure mask, wherein the one or more first sub-areas (221) of the second element (22) are formed by at least one glazed colour layer (70) or a sequence of layers comprising at least one glazed colour layer (70), and wherein the first element (21) is created first and then the first element (21) is used as an exposure mask for structuring one or more layers of a second element (22).

18. Method for producing a see-through security element (2) according to claim 17, characterised in that the first element (21) has at least one metallic layer (60) which is not provided in the one or more first sub-areas (211) of the first element (21) and in particular has been removed by means of demetallisation in the one or more first sub-areas (211) of the first element (21), and / or in that one or more of the colour layers (70) are formed in each case by a dyed negative photoresist.

19. Security document (1) having a see-through security element (2) according to one of claims 1 to 16 and / or a see-through security element (2) produced according to one of claims 17 to 18.

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