Functional element, method for producing the functional element, and product

Abstract

The invention relates to a functional element 2 comprising at least one first relief structure 13 in at least one first region 21, at least one metal layer 12 arranged in at least one sub-region of the at least one first relief structure 13 and, optionally, a preferably polymeric dielectric layer on the side of the metal layer 12 facing the viewer. The at least one first relief structure 13 has a periodic variation of height and depression in the x- and y-directions, the heights being successive to one another with a grating period Λ smaller than the wavelength of light visible to the human eye, the local minima of the depressions defining a base surface and the at least one first relief structure 13 having a relief depth t. Furthermore, the invention relates to a method for manufacturing or modifying a surface and to a product 1 comprising such a functional element 2.

Description

[Technical field]

[0001] The present invention relates to a functional element, in particular a security element, a decorative element, a product surface or a colour standard, a method for producing a functional element, in particular a security element, a decorative element, a colour standard or in particular a method for modifying a product surface, and a product, in particular a security document or decorative surface. [Background technology]

[0002] Product manufacturers face the challenge of attracting the attention of potential target groups to their products through their attractive design and surfaces with functional elements, e.g. optical functionality. A visually appealing appearance increases brand recognition, differentiates products from competitors and increases the chances of counterfeiting and imitation. A further challenge is to equip, modify and / or decorate products with functional surfaces, e.g. sensor-enabled and / or directly structured surfaces.

[0003] Known functional elements include, for example, holograms and computer-generated diffraction gratings. Such functional elements usually generate optically variable effects by targeted diffraction of the incident light into the first and / or one or more higher diffraction orders. In direct reflection, however, they usually only appear as more or less reflective surfaces. Other known functional elements act as interference filters and are formed of an arrangement of several conductive and / or dielectric layers, the dielectric layers having different refractive indices. Through interference filters, functional elements of this type generate color effects in direct reflection.

[0004] Furthermore, it is known to provide functional elements which provide optical effects by combination of color printing with metal mirrors and / or known, preferably metallized, relief structures. However, the problem here is the always present, optically perceptible, registration tolerance between the color printing and the border of the underlying relief structure and / or mirror surface. This registration tolerance therefore limits the design possibilities and / or protection against counterfeiting. Moreover, if there is a mirror surface underneath the color printing, such functional elements do not have a color gradient effect.

[0005] In addition to their optical design, functional elements can also fulfill security aspects, for example ensuring the recognition and authenticity of a product. However, imitations and counterfeits of the above-mentioned functional elements, especially security and decorative elements, are becoming an increasing challenge for their manufacturers and can result, among other things, in security risks and significant economic losses for the industry. Furthermore, it has been shown that the quality and appearance of counterfeits and counterfeits of known functional elements, for example by dot matrix or Kinemax, is also increasing.

[0006] Therefore, there is a need for a novel functional element having an optical effect based on a structure (first line feature) that can be visually seen and / or recognized without aids, which has a clearly different appearance from the optical effect based on the manufacturability of the starting machine and cannot be reproduced by the latter, and which attracts the attention of a target group to itself through a novel optical effect. Summary of the Invention [Problem to be solved by the invention]

[0007] It is therefore an object of the present invention to identify improved functional elements, as well as methods for producing the improved functional elements, in particular methods for modifying product surfaces, and products containing the improved functional elements that are characterized by novel functional structures. [Means for solving the problem]

[0008] This object is achieved by a functional element, in particular a security element, decorative element, product surface or colour standard, preferably according to one of claims 1 to 58, comprising at least one first relief structure in at least one first region, at least one metal layer arranged in at least one sub-region of the at least one first relief structure and optionally a preferably polymeric dielectric layer on a side of the metal layer facing the observer, whereby the at least one first relief structure has ridges and depressions which vary periodically in the x and y directions, the ridges being consecutive to one another with a grating period Λ which is smaller than the wavelength of light visible to the human eye, the local minima of the depressions defining a base surface and whereby the at least one first relief structure has a relief depth t.

[0009] This object is further achieved by a method for producing a functional element, in particular a security element, decorative element or colour standard, or in particular a method for modifying a product surface with a functional element, preferably by a method according to one of claims 59 to 64, in which at least one first relief structure is arranged in at least one first region of the functional element and a metal layer is arranged in at least one sub-region of the at least one first relief structure, optionally and preferably a polymeric dielectric layer is arranged on the side of the metal layer facing the observer, so that the at least one first relief structure has a periodic variation in height and in recesses in the x and y directions, the heights being consecutive to one another with a grating period Λ which is smaller than the wavelength of light visible to the human eye, so that the local minima of the recesses define a base surface and the at least one first relief structure has a relief depth t.

[0010] This object is further achieved by a product, preferably according to claim 65, in particular a security document or decorative surface, which product comprises a functional element in particular according to one of claims 1 to 58, at least one first relief structure is arranged in at least one first region of the functional element and at least one metal layer is arranged in at least one sub-region of the at least one first relief structure, where the at least one first relief structure has heights and depressions which vary periodically in the x- and y-directions, the heights being successive to one another with a grating period Λ which is smaller than the wavelength of light visible to the human eye, the minimum of the depressions defining a base surface, the at least one first relief structure having a relief depth t, and where the product is in particular a banknote, an identity document, a label for product security or decoration, an identity card, a credit card, a cash card, a hang tag or a certificate for a commercial product, in particular a software certificate, packaging, a component for stationary and / or mobile devices, an injection moulded component, a directly structured aluminium component, an automotive, a decorative trim, a colour filter, a sensor, an optical component or a light control.

[0011] By functional element is preferably meant an element that provides a function, which may for example be a security, decorative and / or optical function. The functional element may for example be arranged in a product, so that the product can benefit from the functionality of the element.

[0012] The functional elements can thus be designed, for example, as films, in particular as laminating films, label films, transfer films, etc. It is furthermore also possible to arrange the functional elements in products that are designed as films, in particular as multi-layer films, in which case the functional elements form one or more layers of the product.

[0013] The profile shape, the grating period Λ and / or the relief depth t of the at least one first relief structure are selected in particular such that, at least at a first angle of incidence and / or emergence angle, a coloured, in particular golden or copper coloured, first colour impression is formed in direct reflection in at least one sub-region of the at least one first region in which the metal layer is arranged, whereby light incident at least at the first angle of incidence and which is directly reflected by the at least one metal layer with the relief structure or which is directly transmitted through the at least one metal layer is altered, in particular by plasmon resonance of the at least one metal layer.

[0014] The relief depth t is determined by the spacing of the height maxima of the at least one first relief structure from the base surface in a direction perpendicular to the base surface, and the grating period Λ corresponds to the spacing in the x- or y-direction between two height maxima or two recess minima, which are separated by only one recess or height.

[0015] Area here means a defined surface of a layer or film or plane or ply, in particular occupied by at least one relief structure, in each case when viewed perpendicularly to the plane formed by the layer. Thus, for example, a functional element has a relief structure at least in a first region, but can also have further regions. The region can be further divided into subregions and / or zones and / or zone regions. The spatial directions that span the plane of the region are called the x-direction and the y-direction.

[0016] A layer can be arranged above and / or below other layers. Here, the expressions below and / or above refer in particular to the arrangement of a layer relative to other layers when the observer looks from a viewing direction. It is therefore convenient for the terms below and / or above to represent a frame of reference. The viewing direction is preferably selected such that the layer is viewed perpendicular to the plane spanned by the layer. Deviations from this are conveniently indicated as angles from the normal in degrees.

[0017] The quantized oscillations of charge carrier density in semiconductors and metals are called plasmons and are treated in quantum mechanics as quasiparticles. Furthermore, the term plasmon is a common abbreviation for plasma oscillation quantum. The plasmon resonance in the functional element according to the invention falls into the category of plasmon polaritons.

[0018] Color or chromaticity or monochromaticity or monochromaticity refers to the location of a color in a color space. The color space can in particular be the CIELAB color space. The color space can also be the RGB color space (R=red, G=green, B=blue) or the CMYK color space (C=cyan, M=magenta, Y=yellow, K=black) or a color space such as the RAL, HKS, Pantone® color space.

[0019] Different or different chromaticity means the color difference dE between two color positions in color space.Color space can be specifically CIELAB color space.Different chromaticities that are sufficiently perceptible to the human eye have a color difference dE of at least 2, preferably at least 3, particularly preferably at least 5, and even more preferably at least 10 in CIELAB color space.

[0020] The location of a color, particularly in the CIELAB color space, is usually determined using a colorimeter, for example a "Datacolor 650" spectrophotometer.

[0021] Color position (L * ,a * ,b * ) p and (L * ,a * ,b * ) v The value of dE (or Delta E or ΔE) between is calculated as the Euclidean distance.

number

[0022] Here, the lightness value L * is the color plane (a* ,b * ) on the lightness axis. The a-coordinate indicates the saturation and color intensity between green and red, and the b-coordinate indicates the saturation and color intensity between blue and yellow. The larger the positive values ​​of a and b, and the smaller the negative values, the stronger the color intensity. When a=0 and b=0, the color is achromatic on the lightness axis. Usually, L * can take values ​​between 0 and 100, and a and b can vary between -128 and +127. dE, L * , a * , b * The value is unitless.

[0023] The present invention makes it possible to provide functional elements with an optical appearance that is in clear contrast to the previously known silvery and / or iridescent holographic effects. The optical appearance of the functional elements according to the invention is instead characterized by a defined, predominantly monochromatic golden or copper-colored first color impression, which is seen under normal viewing conditions of direct reflection and / or transmission. Here, the especially metallized relief structure is embedded in and / or covered by a transparent polymer layer, preferably having a refractive index in the range of about 1.4 to 1.6, in particular 1.4 to 1.6.

[0024] The first color impression is stable in direct reflection, in particular over a relatively wide range of inclination angles from 0° to 30° relative to the normal of the plane spanned by the functional element.

[0025] Only at larger angles, for example in the range of 30° to 60°, does a second color impression, such as magenta or light green, become visible in direct reflection. in = α ex (α in is the angle of incident light, α ex is the angle of the reflected light). Direct reflection is also called the zeroth diffraction order.

[0026] In addition to the color stability when tilted about a virtual tilt axis, the first color impression is also perceived by the human eye as stable and therefore unchanging when the functional element is rotated about a virtual rotation axis that is perpendicular to the plane spanned by the at least one metal layer. This color stability when rotating the functional element is not only observed perpendicularly, but also when viewing from a in = α ex = 0°, but also when the functional element is tilted and observed, especially in the tilt angle range of 0° to 30° with respect to the normal to the plane spanned by the functional element. In other words, the initial color impression perceived by the human eye is independent or almost independent of the orientation of the diffraction grating structure.

[0027] This stability of the first color impression with respect to tilt over a larger angular range makes it distinct from the iridescence of so-called diffraction gratings of order 1 or higher, which often produce multiple iridescence already at a tilt of 10°. Moreover, the iridescence of diffraction gratings does not appear in direct reflection, but only at other angles that can be calculated with the diffraction equation.

[0028] Only if the inclination angle is 60° or more does the third color impression corresponding to the first diffraction order light up. This lighting of the third color impression is not visible to the observer, for example in the case of an observation direction perpendicular to the functional element, which is also called the "latent image effect".

[0029] Unlike conventional color impressions based on the absorption of light of specific wavelengths in organic dyes or color pigments, the color impressions described herein are preferably formed by the absorption of light of specific wavelengths in a metal layer. Metal layers are particularly more resistant to photoinduced changes than organic compounds. This results in the color impression according to the invention having the advantage that no fading known from organic dyes or color pigments occurs as a result of irradiation with light having a visible or ultraviolet radiation portion. The color impression is particularly lightfast. Together with the color stability over a relatively wide range of tilt angles, even in the case of rotation of functional elements, the gold or copper color impression is therefore particularly suitable as a lightfast reference color in design or also as a lightfast color reference.

[0030] Furthermore, the invention also makes it possible to produce functional elements more cost-effectively compared to known functional elements with interference filters, e.g. Fabry-Perot filters. Advantageously, the color effects produced in the case of the functional elements according to the invention cannot be counterfeited by conventional holographic techniques and cannot be copied by dot matrix or Kinemax mastering machines.

[0031] The color or color impression of the present invention is formed in particular by the metallized structure itself, which allows functional elements to be integrated into the design, with gold or copper colored areas being free of registration tolerances and therefore in perfect registration with the silver areas of conventional functional elements, such as diffraction gratings.

[0032] Such combinations make it possible to produce functional elements with multiple eye-catching and difficult-to-imitate color impressions in adjacent surface areas, such as, for example, black, red, silver, gold and copper, where the corresponding surface areas, and therefore the color impressions, are in perfect registration with one another. However, counterfeiters who wish to imitate such functional elements, such as security elements, especially those consisting of a combination of different areas by printing one or more additional colors, will not be able to achieve perfect registration of the name. Furthermore, the gradient effect of the optically varying color from the first to the second color impression, i.e. the change in the optical effect in the respective surface area by changing the gradient angle, and the latent image effect if the gradient angle is further changed, will not be present, thus making it possible to identify the corresponding functional element, such as a security element, as a counterfeit, even by an untrained eye.

[0033] Registration accuracy means the relative positional accuracy of two or more layers. The registration accuracy lies within a predefined tolerance range that is as small as possible. At the same time, the registration accuracy of several elements and / or layers relative to each other is an important feature to increase the reliability of the process and / or the quality of the product and / or the protection against counterfeiting. Positionally accurate positioning can be achieved in particular by means of sensorily, preferably optically detectable registration or registration marks. These registration or registration marks either represent specific separate elements or areas or layers or are themselves part of the element or area or layer to be positioned.

[0034] Further advantageous designs of the invention are set forth in the dependent claims.

[0035] According to a preferred embodiment of the invention, the profile shape of the at least one first relief structure is designed asymmetrically in the x-direction and / or in the y-direction. In other words, the profile shape of the at least one first relief structure is designed, in particular, asymmetrically in the x-direction and / or in the y-direction. Furthermore, it is advantageous if the profile shape varies continuously or stepwise, in particular over the relief depth t. This provides the advantage that the profile shape of the at least one first, preferably metallized, relief structure produces a much more visible and distinct color impression for a human observer in the case of typical observation than, for example, a symmetric profile shape. The excitation electric field is advantageously more strongly localized by the asymmetric profile shape, for example, at the narrow tip of the relief structure. This makes resonance and absorption more pronounced. Furthermore, the excitation of the plasmons is different on the two sides of the asymmetric profile shape, so that the incident light generates different effects depending on which surface the light is emitted on.

[0036] Symmetric profile shapes are, for example, sinusoidal, rectangular, binary, etc. In other words, symmetric profile shapes have mirror symmetry when the base surface is used as a mirror surface, where the profile shape remains the same in this mirroring case, and the relief structure is simply shifted by half the grating period Λ. According to the invention, asymmetric profile shapes do not have mirror symmetry in the plane spanned by the base surface.

[0037] Furthermore, it is also possible that the periodic variation of the at least one first relief structure is at least partially superimposed by a random and / or pseudo-random variation.

[0038] Furthermore, it is also possible to at least partially superimpose the periodic variation of the at least one first relief structure on a microstructure, in particular a Fresnel lens and / or a Fresnel freeform surface and / or a micromirror and / or a blazed grating, in particular one with a grating period of more than 5 μm, and / or a computer-generated hologram (CGH) structure.

[0039] This makes it possible to simultaneously realize optical effects of the microstructure itself, or to combine the optical effects of both structures, in addition to the optical effects of at least one first relief structure, such as stable color impressions, color gradient effects and "latent image effects". Thus, for example, areas with optical bulging effects that substantially protrude from the surface or bounce back behind the surface due to the microstructure, for example a Fresnel freeform surface, are not perceived as achromatic, but rather as a golden or copper-colored optical bulging effect of this kind.

[0040] In particular, when a blazed grating structure with a grating period of more than 5 μm, i.e. with an inclined macroscopic surface, is superimposed with a first relief structure, a corresponding inclination of the first relief structure occurs due to the angle of the inclined macroscopic surface relative to the base surface, so that the thus combined relief structure produces a color impression with a larger viewing angle range. A color gradient of the combined relief structure can also be realized in the case of the superposition of the first relief structure with a Fresnel lens structure or a Fresnel freeform surface with varying side angle.

[0041] Preferably, Λ<300 nm, preferably Λ≦280 nm, more preferably Λ≦260 nm applies to the value of the grating period Λ of the at least one first relief structure in the x-direction and / or y-direction, where <, >, ≦ and / or ≧ correspond to the usual symbols in mathematical notation. Gratings with such small grating periods Λ are also called subwavelength gratings. Further preferably, the value of the grating period Λ of the at least one first relief structure in the x-direction and / or y-direction is selected in the range from 150 nm to 260 nm, preferably from 180 nm to 250 nm.

[0042] Furthermore, it is advantageous for t<0.7Λ, preferably t≦0.6Λ, to apply to values ​​of the relief depth t of at least one first relief structure in the x-direction and / or y-direction. The numbers in front of the grating period Λ are to be understood as coefficients multiplied by the grating period Λ. If a deeper grating is selected, this leads to stronger absorption and, as a result, a darker color impression.

[0043] It is also advantageous that t>0.2Λ, preferably t≧0.3Λ, applies to values ​​of the relief depth t of the at least one first relief structure in the x-direction and / or y-direction. If a lower relief depth is found, this has the effect that the excitation of the plasmons becomes weaker, in which case the saturation of the colors formed turns out to be weakly pronounced and therefore only a relatively light, in particular pastel, color impression is achieved.

[0044] Furthermore, the preferably asymmetric profile shape of the at least one first relief structure can be selected such that the height and the width of the recess of the at least one first relief structure relative to a distance t / 2 from the base surface is at least 60% of the grating period, preferably at least 70% of the grating period, and / or at most 40% of the grating period, preferably at most 30% of the grating period. The distance t / 2 from the base surface is also called the full width at half maximum. In this way, the distance between adjacent sides of the at least one first relief structure is determined when the relief depth is t / 2. With such a design, a particularly strong and clear color impression is achieved for a potential human observer.

[0045] In particular, the steepness of the flanks of the at least one first relief structure relative to a distance t / 2 from the base surface can have a value in the range from 60° to 90°, preferably in the range from 70° to 85°.

[0046] The steepness of the flank of at least one first relief structure means here the angle enclosed by the base plane and a tangent line which is located at the flank of the first relief structure at a distance t / 2 from the base plane of the first relief structure, i.e. at half the height of the first relief structure, the distance from the base plane being determined here in a direction perpendicular to the base plane.

[0047] By means of the abovementioned values ​​of flank steepness the advantage is achieved that the intensity of the colour impression produced by the at least one first, preferably metallised relief structure, in particular in direct reflection or direct transmission, is further improved.

[0048] The steepness of the flanks of the at least one first relief structure for each distance starting from the base surface between 25% of the relief depth and 75% of the relief depth is preferably selected to have a value selected from the range of 40° to 90°, preferably 50° to 85°.

[0049] The intensity of the colour impression produced by the at least one first, in particular metallised, relief structure is thereby further improved.

[0050] Furthermore, it is advantageous to select the steepness value of the flanks of the at least one first relief structure to have a value selected from the range of 0° to 50°, preferably from the range of 0° to 40°, for each distance between 0% and 25% of the relief depth and / or between 75% and 100% of the relief depth, in each case starting from the base surface.

[0051] The intensity of the colour impression produced by the at least one preferably metallised relief structure can also be further improved here.

[0052] At least one first relief structure is preferably formed as a two-dimensional grating, preferably as a cross grating and / or as a hexagonal grating, or as a more complex two-dimensional grating. A more complex two-dimensional grating means, for example, a two-dimensional grating with preferably small stochastic variations in the grating period. It also means a two-dimensional grating that is periodically arranged over a length of at least four times the locally present grating period, and at the same time randomly arranged over a length of more than 100 μm. The two-dimensional grating has a series of depressions and heights in the x and y directions. In the case of a cross or hexagonal grating, the grating period Λ of the sequence of heights for both directions is preferably selected in the above range. Here, the grating period is in particular the same in the x and y directions. However, it is also possible that the grating period is different in the two spatial directions.

[0053] Research has further shown that it is inappropriate to form at least one first relief structure as a line grating, i.e. a one-dimensional grating, since such a grating produces only a weak or no desired color impression. The line grating repeats a periodic rise and fall only in one direction. Instead, it is composed of straight or curved, in particular meandering, lines. The need for a 2D grating advantageously further increases protection against counterfeiting, since the production of a cross grating and / or a hexagonal grating requires many more steps that are in line with each other, thereby creating a greater obstacle for counterfeiters.

[0054] According to a preferred embodiment of the functional element according to the invention, the grating period Λ and / or the profile shape and / or the relief depth t of the first, preferably metallized relief structure are designed in such a way that, for an incidence or observation angle of 0° to 30°, at least one first region has a direct reflectance of irradiating light in at least 75% of the wavelength range from 400 nm to 500 nm that is at least 10% lower than the direct reflectance in at least 75% of the wavelength range from 525 nm to 700 nm.

[0055] It is preferred that the grating period Λ and / or the profile shape and / or the relief depth t of the first, preferably metallized relief structure are designed in such a way that at least one first region has a reflectance of irradiating light in at least 70% of the wavelength range from 400 nm to 500 nm that is at least 15% lower than the reflectance in at least 70% of the wavelength range from 525 nm to 700 nm, even more preferred that at least one first region has a reflectance of irradiating light in at least 90% of the wavelength range from 400 nm to 500 nm that is at least 15% lower than the reflectance in at least 90% of the wavelength range from 525 nm to 700 nm, even more preferred that at least one first region has a reflectance of irradiating light in at least 90% of the wavelength range from 400 nm to 500 nm that is at least 20% lower than the reflectance in at least 90% of the wavelength range from 525 nm to 700 nm.

[0056] In addition to the preferred design of the grating period Λ and / or the profile shape and / or the relief depth t of the first, preferably metallized relief structure, in order to prevent the first color impression from appearing too dark, it is preferred that at least one first region has a direct reflectance of irradiated light of more than 30%, preferably more than 40%, even more preferably more than 50%, in at least 90% of the wavelength range from 525 nm to 700 nm.

[0057] The wavelength range from 400 nm to 500 nm corresponds in particular to the wavelength range of violet and blue light, and the wavelength range from 525 nm to 700 nm corresponds in particular to the wavelength range of green, yellow, orange and red light. The above-mentioned design of the at least one first region, in particular with regard to the grating period Λ and / or the profile shape and / or the relief depth t, therefore has the consequence that the proportion of reflected light of blue and / or cyan color is smaller than the proportion of reflected light of the remaining wavelength range visible to the human eye, preferably the wavelength range from 400 nm to 700 nm. Thereby, the first color impression appears to the observer in direct reflection as a golden or coppery shade.

[0058] The above specified values ​​of direct reflectance are measurements from the reflectance spectrum, particularly in the wavelength range of 400 nm to 700 nm.

[0059] In particular, the reflectance spectrum in the case of vertical illumination and observation is preferably measured with an AvaSpec-2048 spectrometer from Avantes. For illumination, a white light source LS-1 from Ocean Optics with a color temperature of 3100°K is used with an optical fiber. For reflectance measurements, a precisely defined directional light beam is irradiated specifically perpendicularly to the surface and the light reflected back perpendicularly is detected by an optical fiber. This optical fiber guides the light to a spectrometer, which measures how much of which wavelength of light is reflected. The reflectance is advantageously calibrated to 100% by a standard. The dark reference here is measured against a matte black surface and the white balance of the spectrometer is performed against an aluminum mirror. A reflectance of 100% therefore corresponds to the reflectance of an aluminum mirror and 0% to the reflectance of a matte black surface. The measured reflectance is therefore preferably a value in the range 0% to 100%.

[0060] The at least one metal layer is preferably made of aluminum and / or silver and / or palladium and / or platinum and / or alloys thereof, in particular made of aluminum or an alloy with a weight percentage of aluminum of 70% or more, preferably 90% or more.

[0061] The at least one metal layer is preferably evaporated and / or sputtered in a vacuum in at least one first sub-region. Alternatively, the at least one metal layer can be applied to the entire surface first and then removed again in the metal-free regions. This can be done using known structuring or demetallizing methods, such as, for example, etching and / or cleaning and / or exposure methods. In particular, the at least one metal layer can be removed in those regions where the remaining metal regions are present in perfect agreement with the regions where the structure-based effects occur.

[0062] It is also possible to imprint the structure according to the invention on the surface of a metal layer and / or metal film and / or metal body and / or to inscribe the structure according to the invention on the surface by means of a laser (eg femtosecond laser).

[0063] According to a preferred embodiment of the invention, the layer thickness of the at least one metal layer is selected to have an optical density (OD) selected from the range of 0.9 to 3.0, preferably 1.1 to 2.5, more preferably 1.6 to 1.9. In particular for transmitted observation of the functional elements, it is advantageous for the at least one metal layer to have an optical density (OD) selected from the range of 1.6 to 1.9.

[0064] This achieves that a sufficient light intensity passes through the areas with the structure according to the invention, in particular for transmission observation of the functional elements, while at the same time the areas without the structure according to the invention, or the structure according to the invention, where much less light passes through the metal layer, appear sufficiently dark to create a contrast that is easily perceptible to the human eye.

[0065] Moreover, this makes it possible to provide a functional element having a relief structure with excellent saturation in specular reflection. Moreover, it makes it possible to provide a functional element which exhibits a first optically variable effect in the case of reflected light observation and a fourth optical effect in the case of transmitted light observation. Moreover, in the case of transmitted light observation in the observation direction, the great advantage is obtained that a corresponding optical effect becomes visible which can only be imitated or counterfeited with great difficulty with existing technologies.

[0066] Optical density (OD) here refers to the transmittance (T) and therefore the transparency of a metal layer relative to an unstructured and therefore smooth metal surface, particularly in the wavelength range of 400 nm to 700 nm. The functional relationship between transmittance (T) and optical density (OD) is formulated as follows: OD = 1g (100 / T [%]). Optical density is unitless.

[0067] According to the above formula, a high transmittance results in a low optical density, and vice versa. Thus, the theoretically highest possible transmittance value for a metal layer, 100%, results in an optical density of 0. For example, the transmittance decreases with increasing thickness of the metal layer, while the optical density increases.

[0068] The reason for the increased transmittance in at least one first region of the at least one first relief structure is probably the increased plasmon excitation by the incident light, which is made possible by the relief structure. It is therefore possible to provide a functional element according to the invention which exhibits at least one optically variable effect in the case of reflected light observation and in the case of transmitted light observation, respectively. Furthermore, it is possible that the optical effect in the reflected light observation is different from the optical effect in the case of a corresponding design in the case of transmitted light observation. Furthermore, it is possible that the optical effect detected in the reflected light observation observed from one side of the functional element is different from the optical effect observed from the other side in the case of a corresponding design. In other words, in each case, optical, preferably different, effects can be detected by the observer in the case of reflection from the front and from the back, respectively.

[0069] The result is a significant advantage in that the corresponding optical effect is visible in direct transmission, observed at an angle perpendicular to the plane in which the layers extend, providing a functional element that can only be counterfeited with great difficulty using existing techniques. Moreover, no comparable effect can be achieved when using transmission diffractive structures of first or higher order.

[0070] The functional element according to the invention is preferably formed as a transfer film or as a laminating film or as a security thread and already has a large number of design possibilities. Furthermore, the functional element, in particular the at least one first region, can preferably have one or more further layers selected from the group consisting of a replication layer, a dielectric layer, a layer of dye, a layer of luminescent material, a gloss color layer, a mask layer, a polymer layer, a metal layer, a protective varnish layer, an adhesive layer, a release layer, a primer layer, a barrier layer, a porous layer, a contrast layer, a sealing layer, an adhesion promoter layer, a carrier layer, a decorative layer.

[0071] The above-mentioned layers can in each case also be arranged on the functional element, in particular in at least one region, above and / or below at least one first relief structure, either individually or in any desired combination with one another. The layers can be applied over the entire surface or only partially, i.e. only in regions. For example, one or more layers can be arranged in a pattern. Also, several patterned layers can be arranged in register with one another. Here, the design variety of the functional element is advantageously further increased.

[0072] The functional elements are preferably designed such that one or more layers of the functional elements, which may be arranged above and / or below the at least one metal layer, and / or one or more layers of the functional elements which may be provided below the at least one metal layer, are made transparent or translucent and in particular have a transmittance in the wavelength range from 400 nm to 700 nm in at least one sub-region of at least one first region of at least 10%, preferably at least 25%, further preferably at least 75% and further preferably at least 90%.

[0073] It is hereby ensured that the optical effect generated by the at least one metal layer and the at least one first relief structure is visible in reflected light observation from above, in reflected light observation from below and / or in transmitted light observation. The color impression of the optical effect can be the same in reflected light observation from above and from below, respectively. The color impression of the optical effect can also be different, for example due to the profile shape of the first relief structure and / or due to differences in the refractive index of the respective materials above or below the at least one metal layer. Different color impressions, for example gold observed from above and red observed from below, can be used for different types of functional elements, such as, for example, foil blankets without dyes or radiation and / or heat management, for example in the case of satellites.

[0074] The functional element according to the invention has, for example, a carrier film, preferably a transparent plastic film with a thickness of 10 μm to 500 μm made of PET, PC, PE, BOPP, a transparent replication layer, preferably made of a thermoplastic or UV-curable replication varnish, an adhesive layer, preferably a cold adhesive layer, a hot adhesive layer or a UV-curable adhesive layer, and a polymer layer, preferably made of a known varnish system with a refractive index in the range of 1.45 to 1.55.

[0075] Furthermore, the functional element according to the invention preferably does not have additional thin layers of high refractive index material, in particular arranged above and / or below the at least one metal layer. The layers of high refractive index material are, for example, ZnS or TiO 2 However, it can also be a high-refractive index replica varnish layer, for example a polymer varnish layer, which is particularly filled with high-refractive index nanoparticles. On the one hand, this leads to a simplification of the manufacturing method, since the method step of depositing, for example vapor-depositing, a high-refractive index material is omitted. Also, such special and expensive materials can be omitted. The functional element according to the invention can therefore be integrated particularly cost-effectively into known product structures and can therefore be produced cost-effectively.

[0076] In a specific embodiment, the functional element may have a thin high refractive index layer, for example a ZnS layer, which is at least partially present on the metal layer, in particular from the side facing the observer. This at least partial high refractive index layer changes the color impression depending on the thickness of the layer due to a change in plasmon resonance, for example from gold or copper to red. The high refractive index layer may be present in the form of motifs such as letters, numbers, symbols, patterns, geometric figures, etc., whereby these motifs appear in a different color compared to the gold or copper colored areas without the high refractive index layer. The thickness of the high refractive index layer is preferably selected in the range of 5 nm to 150 nm, more preferably 10 nm to 50 nm.

[0077] Furthermore, for example, MgF 2It is advantageous if a dielectric layer made of a low refractive index material such as, for example, , or a low refractive index polymer layer is arranged above and / or below the at least one metal layer. The dielectric layer is preferably printed or evaporated so as to be arranged on the entire surface or on an area on the surface of the at least one metal layer. The dielectric layer, in particular the low refractive index layer, has in particular a refractive index of up to 1.45. The thickness of the dielectric, in particular the low refractive index layer, is preferably selected in the range of 5 nm to 2000 nm, more preferably 10 nm to 500 nm.

[0078] If the preferably metallized relief structure is superimposed by a color filter in a known manner, for example by applying separate color filters with a distance of 1 μm or more, an optical effect, in particular a color mixture due to the superposition of the color impression of the preferably metallized relief structure and the function of the color filter, is perceived by the observer in this way, the optical effect of the preferably metallized relief structure is actually dyed by the color filter in the color tone of the color filter.

[0079] According to a preferred embodiment of the present invention, the functional element comprises at least one dye and / or one luminescent material, which dye and / or luminescent material is arranged in the first region or in at least one first region, in particular in the form of a layer. The dye and / or luminescent material is preferably arranged less than 1 μm, more preferably less than 750 nm, more preferably less than 500 nm, more preferably less than 300 nm away from one of the surfaces of the at least one metal layer. The dye and / or luminescent material is preferably arranged in a dielectric layer or in a polymer layer.

[0080] The dyes and / or luminescent materials may for example be applied by a printing process or in vacuum, for example by thermal evaporation.

[0081] Such a close arrangement of dyes and / or luminescent substances on the surface of the at least one metal layer carrying the first relief structure advantageously leads to a strong increase in absorption and / or fluorescence. This enhancement mechanism is called plasmon-enhanced absorption and plasmon-coupled emission. This substantially distinguishes the first relief structure, in particular, from mirror surfaces and "normal" diffractive structures, where this enhancement effect does not occur.

[0082] The dyes and / or luminescent substances can be applied or arranged on the entire surface or area in the form of motifs recognizable to the human eye, such as letters, numbers, symbols, patterns, geometric figures, etc. The dyes and / or luminescent substances are preferably arranged only in areas on the at least one metal layer. Furthermore, the dyes and / or luminescent substances are provided only where the at least one metal layer is adjacent to the at least one first relief structure and generate the above-mentioned effects.

[0083] The term luminescent material refers in particular to fluorescent or phosphorescent materials. Typical fluorescent materials are excited by ultraviolet radiation in the range of 395 nm and / or 365 nm and / or 313 nm and / or 254 nm. Fluorescent materials are known which emit light upon excitation in only one wavelength range or in several wavelength ranges with emission of the same, similar or different colors depending on the wavelength of irradiation in the visible range.

[0084] The dyes and / or luminescent materials can be applied by printing or in a vacuum.

[0085] Examples of vacuum-applied dyes include Patinal Black A or Brown A from Merck, as well as metals that absorb light in the visible spectrum range, preferably in the wavelength range of 400 nm to 700 nm, such as gold, copper or chromium. If such metals are used as the dye layer, there is preferably a very thin dielectric layer between the metal layer and the dye layer, for example a native oxide layer as thin as a few nanometers of an aluminum vapor deposition layer. For example, the thickness of this dielectric layer is between 2 nm and 10 nm. This ensures that the absorption properties of the dye layer, especially of a strongly absorbing metal, are not adversely changed by the electrical connection to the metal layer.

[0086] When using printing methods, different dyes and / or luminescent substances are preferably used than in the case of vacuum coating. The dyes and / or luminescent substances are preferably soluble dyes or luminescent substances or insoluble nanoparticles or pigments. As dyes, dyes from the following substance groups are preferably used: 3+ Or Co 2+ The luminescent material is preferably selected from the following group of materials, either alone or in combination: coumarin, rhodamine, and cyanine.

[0087] The dyes and / or luminescent materials may have a variable absorption behavior in response to an external influence, which may be reversible or irreversible, and preferably results in a color change.

[0088] The functional element according to the invention can have a sensor layer, by which is meant in particular a preferably polymeric layer which comprises dyes and / or luminescent substances with an absorption behavior which reacts variably to external influences.

[0089] Examples of variable dyes and / or luminescent substances that react to external influences are chromogenic materials, which change color or transparency depending on temperature (thermochromic materials), incident light (photochromic materials), voltage and / or current, and pressure.

[0090] In particular, in the case of thermochromic dyes and / or luminescent materials, a predetermined change in temperature triggers a color change, and in particular, in the case of photochromic dyes, a predetermined intensity of radiation triggers a color change.

[0091] The functional element according to the invention can be designed as a sensor element, particularly preferably consisting of a polymeric sensor layer. In particular, the functional element according to the invention, preferably comprising a thermochromic dye and / or a luminescent substance, can be used for time-temperature indicators (also called TTIs), for example in the food industry. Such sensors can indicate, for example, a break in the cold chain. Thermochromic dyes are usually substances that have a structural phase transition accompanied by a color change. An example of a thermochromic dye consists of a mixture of the anthocyanidin dyes cyanidin chloride, dodecyl gallate and hexadecanoic acid, as described in J.Mater.Chem.C, 2013, 1, 2811-2816.

[0092] An example of a photochromic dye is bacteriorhodopsin. Functional elements containing photochromic dyes, in particular bacteriorhodopsin, can be used as security elements that change color when illuminated with a sufficiently high intensity. Alternatively, the functional element can be the light intensity sensor element of a light intensity sensor.

[0093] Further examples of variable dyes and / or luminescent substances that respond to external influences are pH-sensitive dyes and / or luminescent substances that exhibit different colors in aqueous solution depending on the pH.

[0094] Suitable examples include methyl orange, bromothymol blue, and phenolphthalein. In aqueous solution, these show different colors depending on the pH. For example, phenolphthalein is transparent at pH values ​​below 8 and turns magenta from pH values ​​of 9 onwards. At pH values ​​significantly below zero, the indicator turns red-orange.

[0095] A sensor layer containing pH-sensitive dyes and / or luminescent materials can be used, for example, as a pH sensor.

[0096] Further examples of variable dyes and / or luminescent materials that react to external influences are those that react with substances, e.g. gaseous or liquid substances, such that the reaction product has a complex refractive index, absorption coefficient and / or color impression that differs from the dye and / or luminescent material. For example, perylene reacts with gaseous NO 2 and, if present in sufficient concentration, can be detected by a color change.

[0097] The dye level and / or the volume fraction of dye and / or luminescent material can be up to 100% in the layer containing the dye and / or luminescent material, especially if the dye is vacuum coated. The dye level and / or the volume fraction of dye and / or luminescent material is preferably 50% or more, more preferably 75% or more, more preferably 90% or more. In the case of such high coloration levels and / or volume fractions of dye and / or luminescent material, the dye layer can be designed to be extremely thin, whereby the dye and / or luminescent material is in maximal proximity to the metal layer.

[0098] The pigment level and / or volume fraction of dyes and / or luminescent substances, in particular in layers containing dyes and / or luminescent substances applied by printing techniques, is preferably less than 15%, preferably less than 10%, more preferably less than 5%, especially when dyes and / or luminescent substances are used which would not have sufficient adhesion to the metal layer and / or would result in a chemical reaction with the metal layer unless they are made of a stabilizing matrix, e.g. a polymer.

[0099] Mixtures of different pigments, dyes or luminescent materials may also be used.

[0100] The layer containing the dye and / or luminescent substance is preferably transparent and / or has a transmittance of at least 10%, preferably at least 25%, further preferably at least 75%, further preferably at least 90%, in particular in the wavelength range from 400 nm to 700 nm. If the dye is also applied to partial areas in which the relief structure according to the invention and / or the metal layer is not arranged, it is in particular guaranteed here that no substantial staining of the underlying layer is perceptible.

[0101] By the arrangement of the dyes and / or luminescent substances, the first color impression produced can be changed in a targeted manner, especially in direct reflection. For example, the dyes and / or luminescent substances can have an absorption maximum at a wavelength of 550 nm, the absorption having a Gaussian distribution with a width selected in the range of 25 nm to 100 nm, preferably 40 nm to 60 nm. This leads to a deep slump in the reflectance at 550 nm, so that the arrangement of such dyes and / or luminescent substances results in a reddish first color impression. For example, gold nanoparticles with a diameter of about 20 nm have an absorption maximum at about 520 nm.

[0102] The dyes and / or luminescent substances can be applied over the entire surface or only partially in individual areas of the surface. By partial application in areas of the surface, it is achieved that the first color impression is only observed in areas of the surface with the dyes and / or luminescent substances, and that the first color impression is not present in these neighbourhoods where the dyes and / or luminescent substances have not been applied. This makes it possible to generate designs which create a contrast between the first color impression and other optical effects. In addition to subareas which have a colour change, for example in the case of irradiation, colour-stable subareas, with the first colour impression as a reference colour, can also be realised in this way, for example when photochromic dyes and / or luminescent substances are used. In the subareas which contain colour-forming dyes and / or luminescent substances, the first colour impression before the colour change is preferably substantially identical or different from the colour impression of the subareas which do not contain colour-forming dyes. Furthermore, after the colour change, the initial colour impression of the partial areas which contain colour-forming dyes and / or luminescent substances is preferably different from the colour impression of the partial areas which do not contain the dyes and / or luminescent substances.

[0103] Furthermore, at least one glazing color layer can be arranged over the entire surface or at least partially in the area or over the entire surface on at least one first region and / or further region. This glazing color layer can be directly adjacent to the metal layer or separated from the metal layer by a dielectric intermediate layer. Here, the at least one glazing color layer acts as a color filter and generates a color impression detectable for the observer in the corresponding coloring of the color filter. In addition to the color filter effect, at a corresponding small distance from the metal layer, preferably less than 1 μm, more preferably less than 750 nm, more preferably less than 500 nm, even more preferably less than 300 nm, the glazing color layer can also change the first color impression through a significant increase in absorption and / or fluorescence due to plasmon-enhanced absorption and plasmon-coupled emission, as described above.

[0104] The color impression detectable to an observer of the first relief structure and / or the further relief structure and / or the mirror surface beneath the glazing color layer can be determined as a combination of the optical effect of the corresponding relief structure and / or mirror surface and the staining by the glazing color layer. In particular, the at least one glazing color layer is transparent and / or has a transmittance of at least 10%, preferably at least 25%, further preferably at least 75%, further preferably at least 90%, in particular in the wavelength range from 400 nm to 700 nm.

[0105] The two or more glazing color layers can be adjacent to one another or can overlap, at least in areas, where a mixed color is formed from the colors of the two or more color layers and in particular the color of at least one underlying first area.

[0106] The thickness of the at least one glazing colour layer is preferably less than 10 μm, preferably less than 5 μm, more preferably less than 2 μm. In particular, the pigment level and / or the volume fraction of pigments and / or luminescent substances in the glazing colour layer is less than 15%, preferably less than 10%, more preferably less than 5%. The dyes in the glazing colour layer are preferably soluble dyes.

[0107] In one embodiment, the at least one glazing color layer may be positioned at a distance of less than 500 nm, preferably less than 200 nm, from one surface of the at least one metal layer, and more preferably in direct contact with one surface of the at least one metal layer.

[0108] It is further possible for the at least one first area to have patterned sub-areas, in particular sub-areas surrounding this sub-area. Furthermore, at least one layer, in particular a mask layer formed opaquely, can be arranged in the surrounding sub-areas, so that the optical effect generated by the at least one metal layer and the at least one first relief structure is only visible in the sub-areas of the at least one first area that are not covered by the opaque layer. Interesting optical effects are achieved by the formation of the sub-areas.

[0109] The profile shape and / or the relief depth and / or the grating period of the at least first relief structure are preferably further selected such that for a second angle of incidence different from the first angle of incidence the coloured appearance of the light directly reflected at the at least one first region or directly transmitted through the at least one metal layer changes differently.

[0110] In particular, the first color impression appears in direct reflection for a first angle of incidence and the second color impression appears in direct reflection for a second angle of incidence, in particular starting from a normal perpendicular to the base surface of the relief structure, the first angle of incidence being selected from the range 0°-30° and in particular the second angle of incidence being greater than the first angle of incidence by a value selected from the range 10°-45°. For example, the second angle of incidence is a value selected from the range 30°-60°. This makes it possible to define a color change on tilt or a color tilt effect. In the case of reflected light observation and / or in the case of transmitted light observation, at the first or second angle of incidence, a particularly different and stable color impression thus appears in direct reflection for a human observer.

[0111] In particular, the second color impression depends on the azimuth angle. The functional element can therefore be designed to have first regions with azimuth angles that differ or are rotated by at least 15°, preferably 30°, and even more preferably 45°. For example, for azimuth angles of 0° or 90°, a second color impression can be generated that differs from the second color impression for example for an azimuth angle of 45°. The color tilt effect is structure-based and therefore fully coincides with other structure-based effects. In particular, another advantage of this effect is that for the same profile shape, relief depth or grating period, the same first color print is formed in both first regions, independently of the selected azimuth angle. For a first observation angle of, for example, 10°, here all first regions have the same color impression, for example gold. On the other hand, for a second observation angle of, for example, 40°, the color impression of each region differs depending on the orientation of the diffraction grating, i.e. depending on the azimuth angle of each region, and the hidden information item becomes visible only at this second observation angle. Such color effects are also called metameric color effects.

[0112] By azimuth angle is meant in particular the orientation of the relief structure in the plane spanned by the base surface, with the x direction corresponding to 0° and the y direction corresponding to 90°. The azimuth angle of the relief structure can be rotated by a defined angle relative to the base surface and also relative to the relief structure, with the x and y directions being related.

[0113] In the case of a third angle of incidence different from the first and second angles of incidence, an optical appearance different from the optical appearance of the first and second angles of incidence appears, preferably due to the light being diffracted in at least one first region into a first diffraction order, which is called a latent effect and corresponds to the lighting up of the first diffraction order.

[0114] According to a preferred embodiment of the present invention, the functional element has at least one second region, in which at least one second relief structure and / or a mirror surface without a relief structure molded into said mirror surface is formed. The at least one second relief structure is a relief structure, preferably selected individually or in combination and / or superimposed from diffractive relief structures, holographic relief structures, in particular 2D, 2D / 3D or 3D holograms, matte structures, micromirror surfaces, reflective facet structures, refractive, almost achromatic microstructures, blazed gratings, preferably with a grating period of more than 5 μm, lenses, microlens grids, binary random structures, binary Fresnel-shaped microstructures. In particular, a metal layer, which can be designed similarly to at least one of the preferred embodiments of the metal layer in at least one subregion of the first region, is preferably arranged in at least one subregion of the second region.

[0115] In this way, the at least one second relief structure is designed such that, in particular under diffuse lighting, the at least one second region appears preferably in a silvery color and / or in the inherent color of the metal in which the at least one second region is arranged and / or in which the at least one second relief structure is engraved.

[0116] By diffractive relief structures is meant in particular relief structures with a spatial frequency selected in the range of 200 lines / mm to 2000 lines / mm, which in particular generate optically variable effects due to the diffraction of the incident light into the first diffraction order or into higher diffraction orders. These optically variable effects can be, for example, rainbow-like color effects and / or movement effects and / or pumping effects and / or conversion effects. Examples of diffractive relief structures consist, for example, of line gratings or cross gratings. Furthermore, diffractive relief structures can also be formed by computer-generated holograms, for example kinoforms.

[0117] As matte structure, isotropically scattering or anisotropically scattering matte structure can be used. The matte structure exhibits a structure with light scattering properties, preferably with a stochastic or random surface profile. The matte structure preferably has a relief depth t in the range of 100 nm to 5000 nm, preferably 200 nm to 2000 nm. Furthermore, the matte structure preferably has a roughness average Ra selected from the range of 50 nm to 2000 nm, preferably 100 nm to 1000 nm. The matte effect can be isotropic or anisotropic.

[0118] By fine structure is meant a structure that has a spatial frequency less than 200 lines / mm or a grating period greater than 5 μm, and that produces an optical effect that is substantially due to refraction. The effect is therefore nearly achromatic.

[0119] The lenses can be shaped as refractive lenses or concave mirrors or as diffractive lenses or concave mirrors. The microlens grid is preferably formed by a one-dimensional or two-dimensional array of microlenses, for example by cylindrical lenses in the one-dimensional array of microlenses or by microlenses having a spherical or nearly spherical or aspherical shape in each case in the two-dimensional array of microlenses. The grid width of the microlens grid preferably has a value selected from the range of 5 μm to 300 μm, more preferably from the range of 5 μm to 50 μm.

[0120] According to a preferred embodiment of the invention, the functional element has at least one third region, in which at least one third relief structure is formed. The at least one third relief structure is in particular a relief structure consisting of a grating with a grating period Λ of less than 500 nm and greater than or equal to 300 nm and a relief depth t of greater than or equal to 150 nm. The at least one third region is designed to have a preferably red or dark impression, in particular a black impression, in direct reflection, in particular over a relatively wide tilt angle range of at least 0° to 30° with respect to the normal of the plane spanned by the functional element. In particular, a metal layer, which may be designed similarly to at least one of the preferred embodiments of the metal layer of at least one subregion of the first region, is arranged in at least one subregion of the third region.

[0121] Optical effects such as color impressions of the different regions are substantially produced by the structure, so that in particular the at least one first region, the at least one second region and the at least one third region can be positioned in precise register with respect to one another, such that the placement of an additional varnish layer for the colored design can be omitted.

[0122] This allows in particular color schemes of self-explanatory design elements arranged in perfect register, such as flags, which can be conveniently supplemented or extended by further structure-based effects.

[0123] The color stability when the functional elements are tilted, in combination with the perfect registration of the color impressions in direct reflection of corresponding different areas relative to one another, allows their use for detection and / or recognition and / or verification in machines, especially automated processes, such as "optical machine authentication" or "optical telephone authentication". The reading devices used for this can be fixed or mobile.

[0124] In stationary reading devices, such as those used for passport checks at airports or borders, it is often possible to image the passport page with the security element in the case of diffuse illumination. Here, the subareas with the color impression according to the invention are displayed with very high contrast in the image acquisition, so that the registration of the color impression relative to the subareas displayed in silver can be verified by suitable image evaluation. In the case of mobile reading devices, such as smartphones with suitable software, it is also possible to generate image acquisitions, which can be used to verify the registration of the different image elements with respect to one another. Preferably, the software prompts the user to optimize the illumination so that the verification can be optimally performed.

[0125] According to an embodiment of the present invention, at least one first region, at least one second region, at least one third region, or at least one of the first, second or third regions has a patterned shape. An area can be shaped, for example, in the shape of a letter, a number, a symbol, a geometric figure or a motif. In particular, at least one first region can be designed as a mini-text or micro-text.

[0126] By text we preferably mean a sequence of two or more letters, symbols or numbers, minitext preferably having a character height in the range of 0.5mm to 2.5mm, microtext preferably having a character height in the range of 0.125mm to 0.5mm, and nanotext means text with a character height smaller than 0.125mm.

[0127] It is further possible for the first and / or second and / or third regions to be arranged as a plurality of pixels. The pixels can also be designed in a circular, square, hexagonal, motif-shaped or another coherent shape. The pixels can also have an elongated shape, in particular a linear shape. The maximum extent of the pixels in at least one of the spatial directions, preferably in the x-direction and the y-direction, is preferably smaller than 300 μm, preferably smaller than 100 μm, more preferably smaller than 10 μm, more preferably smaller than 5 μm, more preferably smaller than 3 μm. Furthermore, it is advantageous if the pixels are formed in the x-direction and / or the y-direction larger than 1 μm, preferably larger than 1.5 μm. The above-mentioned spread of the pixels results in the effect of a higher resolution of the represented information. Thus, stronger optical effects, for example movement effects over a larger distance, can be realized. Furthermore, the spread of the pixels is sufficiently large so that at least one relief structure of at least one first region herein still has a sufficient number of grating periods so that its optical effect can still occur.

[0128] Furthermore, it is possible to arrange at least one glazing color layer behind and / or below at least one first region and / or second region and / or third region and / or further region, at least regionally or entirely, in particular in the direction perpendicular to the observer's viewing direction, in particular the plane spanned by the functional element.

[0129] In other words, it is possible that at least one glazing color layer is arranged at least in an area or over the entire surface of at least one first relief structure, at least one second relief structure, at least one third relief structure and / or at least one mirror and / or metal layer, perpendicular to the viewing direction of the observer, in particular to the plane spanned by the functional elements. It is possible that at least one glazing color layer is arranged such that it completely or partially overlaps at least one of the first, second and / or third areas, perpendicular to the viewing direction of the observer, in particular to the plane spanned by the functional elements. It is also possible that at least one glazing color layer does not overlap at least one of the first, second and / or third areas.

[0130] The at least one glazing color layer can be either directly adjacent to the metal layer or spaced from the metal layer by a dielectric intermediate layer. The at least one glazing color layer preferably acts as a colored background and thus as an optically contrasting area, in particular giving the observer a detectable color impression in the corresponding coloring of the at least one color layer.

[0131] It is advantageous if the at least one glazing color layer is in particular directly reflected, in particular in the CIELAB color space, over an inclination angle range preferably of at least 0° to 30° to the normal and / or over an inclination angle range preferably of at least 30° to 60° to the normal, and has a total ink holdout dE of 50 to 270, preferably 100 to 270, more preferably 130 to 270 from the first region and / or from the second region and / or from the third region, in particular from at least one sub-region of at least one first, second and / or third region in which the metal layer is arranged.

[0132] It is also advantageous if, in direct reflection, at least one glazing color layer has a dark color, in particular over an inclination angle range preferably of at least 0° to 30° relative to the normal and / or over an inclination angle range preferably of at least 30° to 60° relative to the normal, and has a particularly low lightness value L in comparison with at least one first and / or second and / or third region, which has a light color, in particular a high lightness value L in comparison with at least one glazing color layer.

[0133] Furthermore, it is advantageous for the at least one glazing color layer to have a light color in direct reflection, in particular over an inclination angle range preferably of at least 0° to 30° relative to the normal and / or over an inclination angle range preferably of at least 30° to 60° relative to the normal, with a particularly high lightness value L compared to the at least one first and / or second and / or third region, the at least one first and / or second and / or third region having a dark color, in particular a low lightness value L compared to the at least one glazing color layer.

[0134] Preferably, a first color is understood to be lighter compared to a second color if the first color has a higher lightness value L compared to the second color, and similarly, a third color is understood to be darker compared to the fourth color if the third color has a lower lightness value L compared to the fourth color.

[0135] It is advantageous if the first and / or second region has a total ink holdout dE of 50 to 270, preferably 100 to 270, more preferably 130 to 270, in direct reflection, especially in the CIELAB color space, over an inclination angle range preferably of at least 0° to 30° to the normal and / or over an inclination angle range preferably of at least 30° to 60° to the normal, from the third region and / or the first and / or second region has a total ink holdout dE of 50 to 270, preferably 100 to 270, more preferably 130 to 270, in direct reflection, especially in the CIELAB color space, over an inclination angle range preferably of at least 0° to 30° to the normal. It is advantageous if the third region has a light color with a particularly high lightness value L, preferably compared to the third region, over a range of inclination angles to the normal, and / or over a range of inclination angles to the normal of preferably at least 30° to 60°; it is advantageous if the third region has a dark color with a particularly low lightness value L, preferably compared to the first and / or second region, in direct reflection over a range of inclination angles to the normal, preferably of at least 0° to 30°, and / or over a range of inclination angles to the normal of preferably at least 30° to 60°.

[0136] Alternatively, the first and / or second and / or third regions can be arranged in a grid. It is also possible for the first and / or second and / or third regions to be arranged alternately, i.e. in each case the first and / or second and / or third regions are arranged alternately, in particular directly adjacent, successively to one another. The first and / or second and / or third regions have small distances and / or sizes in at least one dimension of less than 300 μm, preferably less than 100 μm.

[0137] Furthermore, it is possible that at least one first region is designed to be arranged in at least two, preferably at least three, more preferably at least five zones. The zones are preferably designed at least partially to be arranged at a distance of 300 μm or more, preferably at least 1000 μm or more, from each other in the x-direction and / or y-direction, so that they are perceived as being apart from each other by the human eye. In particular, one of the zones, preferably each, has at least one first zone region formed in at least one spatial direction smaller than 2 mm, preferably smaller than 1 mm, more preferably smaller than 0.7 mm. Here, it may be advantageous for the at least one first zone region to occupy at least 20%, preferably at least 30%, more preferably more than 50% of the surface area of ​​the individual zone.

[0138] This has the advantageous effect that it becomes more difficult for a counterfeiter to imitate a gold impression, for example by partially overprinting a counterfeit element that does not have a light-absorbing lattice structure with a yellow ink, and therefore perfect registration cannot be fully achieved with registered color printing, for example by inkjet printing.

[0139] It is also possible that at least one zone has at least one second zone area that is larger than 2 mm, preferably larger than 3 mm, more preferably larger than 5 mm, in at least one spatial direction, and in particular that the surface area of ​​the second zone areas of all zones is at least 20 mm in total. 2 Larger, preferably 30mm 2 Larger, preferably 50 mm 2 This minimum surface area of ​​the broader zone area facilitates a reliable perception by the observer of a gold or copper color impression.

[0140] It is further possible to reduce the extent of at least one zone in one spatial direction, preferably tapering it continuously or stepwise, so that the observer's eye is guided to also look at the narrower first zone area by the wider, more easily detectable second zone area, in which the perfect registration of at least one first zone area with the further areas, sub-areas or zones of the functional element becomes more difficult for a counterfeiter to imitate.

[0141] Furthermore, the at least one first region can be surrounded only in the region or even completely by the at least one third region, the at least one third region having a dimension in one of the spatial directions selected from the range of 30 μm to 1 mm, preferably 50 μm to 300 μm, more preferably 50 μm to 150 μm. In this way, the at least one third region forms a contoured frame or a partial frame, which partially or completely frames the at least one first region. This further emphasizes the contour of the at least one first region, which improves the perceptibility for the observer due to the increased contrast. The optical effects in the first, second and third regions preferably have as different chromaticities as possible and therefore have as good an optical contrast as possible relative to each other. For example, the second region can have a Fresnel freeform surface, which is surrounded by a first region having a first relief structure with a golden yellow impression.

[0142] In a further embodiment, at least one first region can be framed or completely surrounded in a region by at least one second region, where the at least one second region has an extent in one of the spatial directions selected from the range of 30 μm to 1 mm, preferably 50 μm to 300 μm, more preferably 50 μm to 150 μm. In particular, the at least one second region can be framed or completely surrounded in a region by at least one third region, where the at least one third region can be designed similarly to the previous paragraph. Furthermore, the at least one second region can have microtext or nanotext.

[0143] With such a design, the optical effect of the at least one second region draws the viewer's attention to the periphery of the contour, resulting in perfect registration between areas or contours that appear different in direct reflection.

[0144] According to one embodiment of the invention, the plurality of microlenses can be arranged in a grid on the at least one first region. In particular, "arranged in a grid" means a grid arrangement. In particular, the microlenses are arranged such that the at least one first region is perceived by the observer as being magnified. In other words, the at least one first region is located in the focal plane of the microlenses. The microlenses can in each case have a cylindrical or lenticular shape, a spherical or nearly spherical shape, an aspherical shape or another shape.

[0145] A microlens grid can arrange several microlens sub-gratings, preferably in the microlens sub-grating the microlenses are arranged as cylindrical lenses in a one-dimensional array of microlenses or in each case spherical or nearly spherical or aspherical microlenses are arranged in a two-dimensional array of microlenses. In particular, a plurality of microlens sub-gratings different from each other can be arranged in the microlens grid. For example, in one microlens grid, at least one microlens sub-grating with a two-dimensional array of microlenses and at least one microlens sub-grating with a one-dimensional array of microlenses can be provided. The microlens sub-gratings can have different external shapes, in particular triangular, polygonal, circular, elliptical, motif-shaped, pattern-shaped, coding-shaped. Here, these microlens sub-gratings with one-dimensional or two-dimensional arrays of microlenses preferably have in each case the same grating width and / or in each case the same focal length.

[0146] In particular, at least one first region is here arranged in sub-regions such that the sub-regions reveal a plurality of micro-images or moiré icons arranged in a grid form, in particular these micro-images or moiré icons being arranged in alignment with a plurality of micro-lenses arranged in a grid form. The grid width of the grid of micro-images or moiré icons preferably has a value selected from the range of 5 μm to 300 μm, more preferably from the range of 5 μm to 50 μm.

[0147] The grid of microimages or moiré icons has in particular the same or slightly different, in particular a different grid width, compared to the grid width of the microlens grid. The grid of microimages or moiré icons can be arranged slightly twisted, in particular twisted, relative to the microlens grid, or alternatively has a substantially identical, in particular identical arrangement, as the microlens grid, i.e. is substantially not twisted relative to the microlens grid.

[0148] The grid of microimages or moiré icons can have a plurality of partial grids corresponding to the microlens grid, in which the microimages or moiré icons are arranged in a one-dimensional array of microimages or moiré icons or in a two-dimensional array of microimages or moiré icons. In particular, a plurality of partial grids different from one another can be arranged in the grid of microimages or moiré icons. For example, at least one partial grid with a two-dimensional arrangement of microimages or moiré icons and at least one partial grid with a one-dimensional arrangement of microimages or moiré icons can be provided in the grid of microimages or moiré icons. The partial grids can have different external shapes, in particular triangular, polygonal, circular, elliptical, motif-shaped, pattern-shaped, coding forms. The microimages or moiré icons can be formed in the partial grids such that an optical effect assigned to each partial grid is formed. Thus, a plurality of partial grids can generate different optical effects in the grid of microimages or moiré icons, which together reveal a combined optical effect or which reveal separate optical effects present next to each other.

[0149] Due to these different optical effects, for each partial grating, the microimage or moiré icon may be formed differently, in particular in a perpendicular observation to the plane spanned by the functional element, with the first area and / or the second area and / or the third area and / or the glazing color layer in front of and / or behind the first area and / or the second area and / or the third area.

[0150] Furthermore, due to these different optical effects, for each partial grating the micro-image or moiré icon can have a different number of first areas and / or second areas and / or third areas and / or glazing color layers in front of and / or behind the first areas and / or second areas and / or third areas and / or glazing color layers, in particular in vertical observation onto the plane spanned by the functional element.

[0151] By microimages is preferably meant complete motifs as well as incomplete motifs, i.e. fragments of motifs. The motifs may in particular be chosen from images, symbols, logos, coats of arms, flags, portraits, alphanumeric characters or combinations thereof.

[0152] A sub-region preferably consists of a number of pixels, the pixels being designed as already described above.

[0153] Furthermore, the sub-regions may be composed of a plurality of pixels, from which at least one second region and / or at least one third region are formed. The sub-regions preferably have pixels that constitute at least one first region and / or pixels that constitute at least one second region and / or pixels that constitute at least one third region. In particular, microimages with different chromaticities and / or with an achromatically high contrast between the foreground and background of the motif are thus possible. For example, microimages composed of pixels with a bright white or silver coloring, a dark gray or black coloring, and / or a gold or copper coloring are possible here.

[0154] The sub-regions can also be designed through the pixel array so that a gradual transition is achieved from the increased array of pixels constituting at least one first region to the increased array of pixels constituting at least one second region. A perceptible gradual transition from a golden or copper appearance to a silver appearance is now possible. The pixels can also have an elongated shape, in particular a line shape.

[0155] Furthermore, by combining the variants of the previous embodiment, it is possible to make the gold or copper hue of the sub-regions lighter, i.e. closer to a silver hue, which can be achieved by arranging the pixels that do not constitute at least one third region as a mixture, preferably a probability distribution, of the pixels that constitute at least one first region and at least one second region.

[0156] Alternatively or additionally, the motif of the micro-image motif or the motif of the moiré icon may be composed of pixels having a silver reflective appearance and pixels having a dark grey to black appearance in one area of ​​the motif, and pixels having a gold or copper appearance and pixels having a dark grey to black appearance in another area of ​​the motif. In other words, the area of ​​the motif of the micro-image motif or the motif of the moiré icon may be composed of pixels constituting at least one second area and pixels constituting at least one third area, and in another area of ​​the motif may be composed of pixels constituting at least one first area and pixels constituting at least one third area. Multi-coloured designs of the functional elements are possible here, for example, where a gold or copper moving effect and a silver moving effect are present in the functional element spatially separated from each other.

[0157] According to a further embodiment of the invention, at least one glazing color layer is arranged below the plurality of microlenses, in particular above at least one of the first, second and / or third regions.

[0158] According to a further embodiment variant of the functional element according to the invention, the motif is formed by a plurality of pixels constituting at least one first region and a plurality of pixels constituting at least one third region. With regard to the range of pixels reference is made to the above description. In this way the distribution of the pixels is designed such that the motif is perceived by the observer in direct reflection as a golden-tinted greyscale image, in particular as a halftone image. The functional element according to the invention here further provides the effect that the greyscale or halftone image has a colour gradient effect in direct reflection or in the zero diffraction order. In particular the functional element further provides a surprising potential effect in the first diffraction order in case of strong gradients, in particular at least in the first region.

[0159] An alternative variant for producing a greyscale image, especially as a halftone image, dyed in golden yellow, is to provide pixels in a planar first area using a high-resolution demetallization method, in which the metal is removed. This can be done using known structuring or demetallization methods, for example etching and / or cleaning and / or exposure methods. Both the metal layer and the demetallized areas can be backed at least partially by a planar colour layer, so that the greyscale image can be viewed with good contrast. Colour mixing effects are further possible here too.

[0160] According to an embodiment of the present invention, at least one first region can be arranged on a first electrode layer. In particular, the first electrode layer can be arranged on or used in a reflective display. The first electrode layer can include further layers or functional elements, such as, for example, electrically conductive connection parts and / or electromagnetic shields and / or heat shields and / or light shields and / or circuits.

[0161] The first electrode layer has an optical effect produced by at least one first region.

[0162] Furthermore, it is advantageous if a switchable layer, for example an electrochromic layer, a liquid crystal layer or a PDLC (polymer dispersed liquid crystal) layer, is arranged on the first electrode layer. This switchable layer is characterized in that its appearance can be changed by the application of a voltage. In particular, when no voltage is applied, for example a PDLC layer appears cloudy to the observer and appears transparent as long as a voltage is applied. The thickness of the switchable layer is typically in the range of 2 μm to 20 μm.

[0163] Furthermore, a second electrode layer can be arranged on top of the first electrode layer and / or the switching layer. The second electrode layer is preferably designed to be transparent or semi-transparent and / or transparent and / or has a transmittance of at least 50%, preferably at least 75%, more preferably at least 90%, especially in the wavelength range of 400 nm to 700 nm. Examples of such transparent second electrode layers include printed poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) layers or alternatively structured, preferably microstructured, metal layers that appear transparent to the human eye. For example, such microstructured metal layers can consist of a metal mesh and / or a metal grid, which consists of metal tracks about 5 nm to 100 nm wide running in the x and y directions, the metal tracks having a distance from each other of, for example, 50 nm to 1000 nm. By the intersections of the mesh, the entire surface area of ​​the metal mesh is conductively connected.

[0164] The first electrode layer is advantageously arranged below the second electrode layer, in other words on the side of the second electrode layer facing away from the observer, and in particular the switchable layer is arranged between the first and second electrode layers.

[0165] The properties of the at least one first region can hereby be advantageously integrated into the reflective display. In particular, the optical effects of the switchable layer can be combined with the color effects of the lower electrode layer. Thus, in the case of a reflective display with a switchable layer, for example a PDLC layer, the gold or copper impression of the first electrode layer becomes visible, or at least becomes more visible, in particular in sub-regions of the display which switch from cloudy to transparent by the application of a voltage. However, when no voltage is applied to the reflective display, the at least one first region is substantially invisible, or at least only weakly visible. In this way, a functional element of the reflective display is obtained which is only substantially perceptible to the observer as long as a corresponding voltage is applied to the reflective display.

[0166] In particular, the switchable layer can contain a dye and / or can be dyed, so that in addition to the optical switching function, a color filter function can also be obtained. This has the advantage that the appearance of the switching layer when a voltage is applied changes from the color of the dye to the gold or copper color of the bottom electrode layer when a voltage is applied. This opens up even more design possibilities.

[0167] The pigmentation level and / or the volume percentage of dye in the switchable layer is preferably less than 15%, preferably less than 10%, more preferably less than 5%.The dye in the switchable layer is preferably a soluble dye or an insoluble nanoparticle.

[0168] According to a further embodiment variant of the functional element according to the invention, it is formed as a sensor element for detecting a substance to be detected and / or a changing environmental condition, such as, for example, pressure, temperature, light incidence, electrical voltage and / or current. For this, a polymeric sensor layer is preferably arranged, in particular on the side of the metal layer facing the observer. The sensor layer is formed as already explained above. Dyes and / or luminescent substances are arranged in the sensor layer, where the dyes are preferably chromogenic, preferably thermochromic and / or photochromic and / or pH-sensitive.

[0169] This has the advantageous effect that the refractive index and / or absorption coefficient of the sensor area changes when the sensor layer comes into contact with a sufficient amount of the substance to be detected. This changes the color impression perceptible to the human eye. Due to the increased absorption of the dye at the surface of the at least one metal layer with the first relief structure, this change in color impression is already perceptible at relatively low concentrations of the substance to be detected. This enhancement mechanism is called plasmon-enhanced absorption. The change in color impression perceived by the human eye is much greater here compared to a metal layer with a sensor layer without a relief structure.

[0170] Furthermore, a contrast layer, preferably dielectric, can be arranged in the region above the sensor layer from the observer's perspective, so as to preferably cover at least a sub-region of the sensor layer and prevent contact with the substance to be detected and / or the influence of changing environmental conditions. The contrast layer preferably has a refractive index close to the refractive index of the medium containing the substance to be detected. The refractive index of the contrast layer preferably differs from the refractive index of the medium containing the substance to be detected by at most ±10%, more preferably at most ±5%, even more preferably at most ±2%.

[0171] The areas in which the at least one first relief structure, the metal layer and the sensor layer are arranged and in which the contrast layer is not arranged preferably form sensor areas which are in contact with a medium containing the substance to be detected and / or are exposed to the effects of changing environmental conditions.

[0172] The function of this contrast layer is to protect the covered partial areas of the sensor layer from contact with the substance to be detected and / or from the influence of environmental conditions, so that these areas do not show a change in color impression caused by the substance to be detected. In this way, the contrast layer has the advantageous effect that the contrast between areas with a color change and areas without a color change is particularly easily perceived by the human eye.

[0173] It is also possible for the functional element to further comprise a filtering transparent layer, in particular an open-hole layer, which is arranged above the sensor layer from the viewpoint of the observer. The filtering layer is arranged in particular in the sensor area. Furthermore, the filtering layer is in particular permeable to the substance to be detected present in the medium and prevents other substances present in the medium from reaching the sensor layer. This further makes it possible to reduce or prevent undesired reactions of the sensor layer with other substances also present in the medium. Optionally, a further, preferably polymeric, sealing layer is provided, which prevents the medium from escaping at the edge of the sensor element. Thus, the preferably polymeric sealing layer is not permeable to the medium and is preferably chemically inert to the medium.

[0174] It is also possible for the functional element, preferably in the form of a microfluidic system, to have a vertically running channel. This flow path is preferably formed by a polymeric sealing layer and can optionally be sealed by a polymeric sealing layer, which is preferably transparent. A medium is hereby guided past the sensor area in the flow path.

[0175] The production of the functional element, in particular the sensor element, can be realized as follows: A first relief structure can be produced by known methods, such as holographic two-beam exposure or electron beam lithography, on a glass substrate. A nickel shim with the first relief structure can be obtained therefrom according to the known state of the art by a galvanic copying process. The nickel shim is replicated according to known methods, after which the first relief structure can be produced in a flexible film, for example in a roll-to-roll process, such as thermal or UV replication.

[0176] It is particularly advantageous for the functional element, preferably the sensor element, if the first relief structure is realized on a rigid substrate, for example a glass or quartz substrate. This allows for easier handling of, for example, liquid media. For this reason, the first relief structure can be directly copied from the nickel shim onto a rigid substrate, for example a glass or quartz substrate, in a UV copying process. Known processes for this use so-called sol-gel materials, for example ormocells, which are applied in liquid form to the rigid substrate. The nickel shim is then placed on the rigid substrate, for example a glass or quartz substrate, so that a thin film of sol-gel material remains between the rigid substrate and the nickel shim. After this, the sol-gel material is hardened by UV irradiation through the rigid substrate, for example a glass or quartz substrate, and the nickel shim is peeled off. A metal layer can then be evaporated or sputtered in vacuum onto the surface of the hardened sol-gel layer with the first relief structure. The sensor layer can then be applied as a thin layer onto the metal layer, for example by spin coating.

[0177] Alternatively or additionally, during the production of the functional element according to the invention, partial regions of the functional element, in particular at least one first region, can be stamped onto the substrate, preferably by means of a patterned stamping die. Furthermore, it is also possible to apply the functional element to the substrate over the entire surface by means of a non-specific laminating roller. Here, it is further particularly advantageous if the surface of the substrate onto which the functional element is stamped has a surface structure, for example a matt structure, and the stamping pressure is selected such that during stamping the base surface of the first relief structure is deformed according to the surface structure.

[0178] It is furthermore possible to process the functional element in one working step by means of a blind stamping tool with a stamping surface formed with a surface structure. In this case, the stamping pressure is selected such that during the pressing of the blind stamping tool, the base surface of the first relief structure is deformed according to the surface structure of the blind stamping tool. In this way, it is also possible to subsequently individualize the functional element in a subsequent working step by a corresponding deformation of the base surface of the at least one first relief structure, so that the functional element or the product with the functional element can be provided with the additional optical effects already mentioned above.

[0179] The use of functional elements in products, for example security documents or decorative surfaces, has proven to be particularly advantageous: thus, the functional elements can be arranged in the product according to the design, for example to be observed in top view, but also through window areas, so that they can be observed in top view and through view.

[0180] The features described above can of course be used in an equivalent manner in the method, and the features of the method described above can also be used in the product.

[0181] The present invention will now be described by way of example with reference to some example embodiments using the accompanying drawings, in which: FIG. [Brief description of the drawings]

[0182] [Figure 1] FIG. 1 is a schematic cross-sectional view of a product that constitutes a functional element. [Diagram 2] FIG. 2 shows details of the products that make up the functional elements. [Figure 3a] FIG. 3a is a schematic cross-sectional view of a functional element. [Figure 3b] FIG. 3b is a schematic cross-sectional view of a functional element. [Figure 4a] FIG. 4a is a schematic top view of a functional element. [Figure 4b] FIG. 4b is a schematic top view of a functional element. [Figure 4c] FIG. 4c is a schematic top view of a functional element. [Figure 4d] FIG. 4d is a schematic cross-sectional view of a functional element. [Figure 5a] FIG. 5a is the reflectance spectrum. [Figure 5b] FIG. 5b is the reflectance spectrum. [Figure 6a] FIG. 6a shows a schematic relief structure. [Figure 6b] FIG. 6b is a top view of the functional element. [Figure 7a] FIG. 7a is a schematic top view of a functional element. [Figure 7b] FIG. 7b is a top view of the functional element. [Figure 8a] FIG. 8a shows a detail of the functional element. [Figure 8b] FIG. 8b is a schematic top view of a functional element. [Figure 8c] FIG. 8c is a schematic top view of a functional element. [Figure 9] FIG. 9 is a top view of the functional element. [Figure 10] FIG. 10 shows two top views of the same functional element, one observed in reflected light and one observed in transmitted light. [Figure 11a] FIG. 11a is a top view of the functional element. [Figure 11b]FIG. 11b is a schematic top view of the functional element. [Figure 11c] FIG. 11c is a schematic top view of the functional element. [Figure 12] FIG. 12 is a top view of the functional element. [Figure 13] FIG. 13 is a top view of the functional element. [Figure 14] FIG. 14 is a schematic top view of a functional element. [Figure 15a] FIG. 15a is a schematic cross-sectional view of a functional element. [Figure 15b] FIG. 15b is a schematic cross-sectional view of a functional element. [Figure 15c] FIG. 15c is a schematic cross-sectional view of a functional element. [Figure 15d] FIG. 15d is a schematic cross-sectional view of a functional element. [Figure 15e] FIG. 15e is a schematic top view of the functional element. [Figure 16] FIG. 16 is a schematic top view of the functional elements. [Figure 17] FIG. 17 is a schematic cross-sectional view of a functional element. [Figure 18] FIG. 18 is a schematic diagram of a product including a functional element. [Figure 19] FIG. 19 is a schematic cross-sectional view of a functional element. [Figure 20] FIG. 20 is a schematic diagram of a product including a functional element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0183] In Fig. 1 a cross-section is shown of an example of a product 1 consisting of a functional element 2. Fig. 2 shows an example embodiment of a product 1 consisting of, for example, a functional element 2 according to the cross-section of Fig. 1.

[0184] The product 1 constituting the functional element 2 according to Fig. 1 or 2 is, for example, a bank note. However, it is also possible for the product 1 to be, for example, an ID document, a label for product security or decoration, an ID card or credit card, a bank card, a hang tag or certificate for a commercial product, in particular a software certificate, packaging, a component for stationary and / or mobile devices, an injection moulded component, a directly structured aluminium component, an automotive, a decorative trim, a colour filter, a sensor, an optical component, a light control. The following description is therefore not limited to bank notes but can equally be applied to the further above-mentioned embodiments of the product 1.

[0185] Here, the product 1 comprises a carrier substrate 10 and a functional element 2 applied to the carrier substrate 10 .

[0186] The carrier substrate 10 is preferably a paper substrate, for example with a layer thickness in the range of 50 μm to 500 μm. However, it is also possible that the carrier substrate 10 is a plastic substrate or a carrier substrate consisting of one or more plastic and / or paper layers. Furthermore, in addition to the functional element 2, it is also possible that one or more further functional elements are applied to the carrier substrate 10 or integrated into the layer structure or layers of the carrier substrate 10. Thus, the carrier substrate 10 can have as further functional elements, for example one or more of the following elements: a watermark, a security print, a security thread, an antenna, a chip, a patch or a strip with at least one security function consisting of a holographic structure or an optical diffraction structure.

[0187] The functional element 2 has at least one first relief structure 13 in a first region 21, as well as a metal layer 12 arranged in at least one sub-region of the at least one first relief structure 13 and, optionally, a preferably polymeric dielectric layer provided on the side of the metal layer facing the viewer.

[0188] The at least one metal layer 12 is preferably made of aluminum and / or silver and / or palladium and / or platinum and / or alloys thereof. In particular, the at least one metal layer 12 is made of aluminum or an alloy with a weight percentage of aluminum of 70% or more, preferably 90% or more. The at least one metal layer 12 is preferably evaporated and / or sputtered in a vacuum in at least one first sub-region of the at least one first region 21.

[0189] Alternatively, the metal layer 12 can first be applied to the entire surface and then removed again in the metal-free areas, for example using known structuring or demetallization methods, such as etching and / or cleaning and / or exposure methods.

[0190] It is also possible to imprint the structure according to the invention onto the surface of a metal layer and / or metal foil and / or metal body and / or to inscribe the structure according to the invention onto the surface by means of a laser (eg femtosecond laser).

[0191] According to a preferred embodiment of the present invention, the thickness d of the at least one metal layer 12 is metal is selected to have an optical density (OD) selected from the range of 0.9 to 3.0, preferably 1.1 to 2.5, more preferably 1.6 to 1.9. In particular for transmission observation of the functional elements, it is advantageous if the metal layer has an optical density (OD) selected from the range of 1.6 to 1.9. This achieves that a light intensity sufficient for transmission observation of the functional elements in particular passes through the areas with the structure according to the invention. At the same time, areas without structures, or structures where much less light passes through the metal layer, appear sufficiently dark to generate a contrast that is easily perceptible to the human eye.

[0192] The functional element is preferably designed such that one or more layers of the functional element 2, which may be arranged above and / or below the at least one metal layer 12 and / or one or more layers of the functional element 2, which may be provided below the at least one metal layer 12, are made transparent or translucent and have a transmittance of at least 10%, preferably at least 25%, more preferably at least 75% and even more preferably at least 90%, in particular in at least one sub-region of at least one first region 21, in particular in the wavelength range from 400 nm to 700 nm.

[0193] The functional element 2 is, for example, a transfer film, a label film, a laminating film or a security thread. Furthermore, the functional element 2, in particular the at least one first region 21, can preferably have another one or more further layers selected from the group of a replication layer, a dielectric layer, a layer of dye, a layer of luminescent material, a gloss color layer, a mask layer, a polymer layer, a metal layer, a protective varnish layer, an adhesive layer, a release layer, a primer layer, a barrier layer, a porous layer, a contrast layer, a sealing layer, an adhesion promoter layer, a carrier layer, a decorative layer. The above-mentioned layers can in each case be arranged on the functional element, in particular in the at least one first region 21, above and / or below the at least one first relief structure 13, either individually or in any desired combination with one another. The layers here can be applied not only over the entire surface but also only partially, i.e. in areas. For example, one or more layers can be arranged patterned. It is also possible to arrange several patterned layers in register with one another.

[0194] Thus, the functional element 2 according to the invention has, for example, a carrier film, preferably a transparent plastic film with a thickness of 10 μm to 500 μm made of PET, PC, PE, BOPP, a transparent replication layer, preferably made of a thermoplastic or UV-curable replication varnish, an adhesive layer, preferably a low-temperature adhesive layer, a high-temperature adhesive layer or a UV-curable adhesive layer, and a polymer layer, preferably made of a known varnish system with a refractive index in the range of 1.45 to 1.55.

[0195] Furthermore, the functional elements 2 according to the invention are preferably made of ZnS or TiO 2 , which are in particular arranged above and / or below the at least one metal layer 12. 2 or in particular a polymer varnish layer filled with high refractive index nanoparticles.

[0196] Furthermore, for example, MgF 2 It is advantageous if a dielectric layer and / or a low-refractive-index polymer layer made of a low-refractive-index material such as is arranged above and / or below the at least one metal layer 12. The dielectric layer is preferably printed or evaporated so as to be entirely or partially arranged on the surface of the at least one metal layer 12. The low-refractive-index layer in particular has a refractive index of at most 1.45.

[0197] According to a preferred embodiment of the invention, the functional element 2 comprises at least one dye and / or one luminescent substance, which dye and / or luminescent substance is arranged, in particular in layer form, in the first region 21 or in at least one of the first regions 21. The dye and / or luminescent substance is preferably arranged less than 1 μm, more preferably less than 750 nm, more preferably less than 500 nm, even more preferably less than 300 nm away from one of the surfaces of the at least one metal layer 12. The dye and / or luminescent substance is preferably arranged in a dielectric or polymer layer.

[0198] The dyes can be applied by printing or in a vacuum. Examples of vacuum applied dyes include Merck's Patinal Black A or Brown A, and metals that absorb light in the visible spectrum, preferably in the wavelength range of 400 nm to 700 nm, such as gold, copper or chromium.

[0199] The dye and / or luminescent substance is preferably only partially arranged on the at least one metal layer 12. Furthermore, the dye and / or luminescent substance is only provided where the at least one metal layer 12 is adjacent to the at least one first relief structure 13, thereby generating the above-mentioned effects.

[0200] When using printing methods, different dyes are preferably used than in the case of vacuum application. The dyes and / or luminescent substances are preferably soluble dyes or luminescent substances or insoluble nanoparticles or pigments. As dyes, dyes from the following substance groups are preferably used: 3+ Or Co 2+ The luminescent material is preferably selected from the following group of substances, either alone or in combination: coumarin, rhodamine, and cyanine.

[0201] The pigmentation degree and / or volume fraction of the dyes and / or luminescent substances can be up to 100% in the layer containing the dyes and / or luminescent substances, especially if the dyes and / or luminescent substances are vacuum coated. The dye level and / or volume fraction of the dyes and / or luminescent substances is preferably 50% or more, more preferably 75% or more, and particularly preferably 90% or more. In the case of such high pigmentation levels and / or volume fractions of the dyes and / or luminescent substances, the dye layer can be designed to be very thin, whereby the dyes and / or luminescent substances are in maximal proximity to the metal layer.

[0202] The volume fraction of dyes and / or luminescent substances in the layers applied by printing containing pigment levels and / or dyes and / or luminescent substances is preferably less than 15%, more preferably less than 10%, even more preferably less than 5%, especially when dyes and / or luminescent substances are used which, unless made of a stabilizing matrix, e.g. a polymer, do not have sufficient adhesion to the metal layer and / or result in a chemical reaction with the metal layer. Mixtures of different pigments and / or dyes and / or luminescent substances can also be used.

[0203] The layer containing the dye and / or the luminescent substance is preferably transparent and / or has a transmittance of at least 10%, preferably at least 25%, more preferably at least 75%, more preferably at least 90%, in particular in the wavelength range from 400 nm to 700 nm. If the dye is also applied to partial areas in which the relief structure and the metal layer are not arranged, it is in particular ensured here that no substantial staining of the underlying layer is perceptible.

[0204] By the arrangement of the dyes and / or luminescent substances, the first color impression produced can be changed in a targeted manner, especially in direct reflection. For example, the dyes and / or luminescent substances can have an absorption maximum at a wavelength of 550 nm, where the absorption has a Gaussian distribution with a width selected in the range of 25 nm to 100 nm, preferably 40 nm to 60 nm. This leads to a deep slump in the reflectance at 550 nm, so that the arrangement of such dyes and / or luminescent substances results in a reddish first color impression.

[0205] The dyes and / or luminescent substances can also be applied over the entire surface or only partially in individual areas of the surface. By partial application in areas of the surface, it is achieved that the first color impression is only observed in areas of the surface which have the dyes and / or luminescent substances, while in these neighbourhoods where the dyes and / or luminescent substances have not been applied, the first color impression is absent. This makes it possible to create designs which create a contrast between the first color impression and other optical effects.

[0206] Furthermore, it is possible for a glazing color layer 14 to be arranged over the entire surface or at least partially in the area or over the entire surface on at least one first region 21 or further regions. This glazing color layer 14 can be either directly adjacent to the metal layer 12 or spaced from it by a dielectric intermediate layer. The at least one glazing color layer 14 acts here as a color filter and generates a color impression detectable for the observer in a corresponding coloring of the color filter. In addition to the color filter effect, at a corresponding small distance from the metal layer 12, preferably less than 1 μm, more preferably less than 750 nm, more preferably less than 500 nm, even more preferably less than 300 nm, the glazing color layer can also change the first color impression by a significantly increased absorption and / or fluorescence, as described above, by plasmon-enhanced absorption as well as plasmon-coupled emission.

[0207] The color impression detectable to an observer of the first relief structure and / or the further relief structure and / or the mirror surface beneath the glazing color layer 14 can be determined as a combination of the optical effect of the corresponding relief structures and / or mirror surfaces and the coloring by the glazing color layer 14.

[0208] In particular, the at least one glazing colour layer 14 is transparent and / or has a transmittance of at least 10%, preferably at least 25%, more preferably at least 75%, more preferably at least 90%, especially in the wavelength range from 400 nm to 700 nm.

[0209] Two or more glazing color layers 14 can be adjacent to each other, or two or more glazing color layers 14 can overlap, at least in areas, where a mixed color is formed from the colors of the two or more color layers 14 and in particular the color of at least one underlying first area 21.

[0210] The thickness of the at least one glazing colour layer 14 is preferably less than 10 μm, more preferably less than 5 μm, even more preferably less than 2 μm. In particular, the pigment level and / or the volume fraction of pigments and / or luminescent substances in the glazing colour layer 14 is less than 15%, preferably less than 10%, even more preferably less than 5%. The dyes in the glazing colour layer 14 are preferably soluble dyes.

[0211] In one embodiment, the at least one glazing color layer 14 may be positioned at a distance of less than 500 nm from one surface of the at least one metal layer 12, preferably less than 200 nm, and more preferably in direct contact with one surface of the at least one metal layer 12.

[0212] It is furthermore also possible for the at least one first area 21 to have a patterned partial area, in particular a partial area surrounding this partial area. Furthermore, at least one layer, in particular a mask layer 12 which is formed opaque, can be arranged in the surrounding subareas, so that the optical effect produced by the at least one metal layer 12 and the at least one first relief structure 13 is only visible in the subareas of the at least one first area which are not covered by the opaque layer.

[0213] In the embodiment according to FIGS. 1 and 2, the functional element 2 extends, for example, over at least the width or length of the product 1 .

[0214] Furthermore, the functional element 2 covers a window area 11 of the carrier substrate 10, which has openings or through-holes or is formed transparent. Thus, at least the first area 21 of the functional element 2 or at least one first relief structure 13 is visible in this area both when viewing the product 1 from the front and when viewing it from the rear. Here, in particular, the presence of different color impressions can be observed from the front and from the rear. For example, in the area of ​​the window, the functional element 2 can appear copper-colored when viewed from the front and gold-colored when viewed from the rear. The different color impressions can be produced by an asymmetric diffraction grating profile and / or by differences in the refractive index of the dielectric layers on both sides of the metal layer 12 and / or by a dye layer in one of the dielectric layers on either side of the metal layer 12.

[0215] Alternatively or additionally, the functional element 2 may have a first area 21 that is not arranged in the window area 12 of the product 1, but rather is applied entirely to the opaque area of ​​the substrate 10. Such a functional element 2 may be formed, for example, as a patch or strip.

[0216] Furthermore, it is also possible, especially when the product 1 is a card-like product 1, to embed the functional elements 2 in a layer of the carrier substrate 10. In this case, the functional elements 2 are provided as patches or strips on one ply of the card-like product 1 and are subsequently laminated with a further ply of the card-like product 1 and are thus embedded within the card-like product 1.

[0217] Figures 3a and 3b show details of a functional element 2 according to the invention, for example according to Figure 1 or 2, in order to explain different parameters of the profile shape. Thus, the functional element 2 has a first relief structure 13 in at least one first region 21. The layer thickness d metal is also arranged in a sub-area of ​​the at least one first relief structure 13, and optionally a preferably polymeric dielectric layer is arranged on the side of the metal layer 12 facing the viewer.

[0218] The at least one relief structure 13 has a series of ridges and valleys in at least one direction determined by an assigned azimuthal angle, the ridges being contiguous with one another with a grating period Λ smaller than the wavelength of visible light. The one first relief structure 13 further has a relief depth t.

[0219] The color impression or color effect of the relief structure 13 is due to direct reflection, hence specular reflection, or α in = α ex It is visualized under the condition where α in are the angles of incident light of 100 and 200, and α ex is the angle of the reflected light 300, relative to the surface normal or normal 400 of the base surface. Preferably, by a corresponding selection of the relief depth t and the profile shape of the relief structure 13, a clearly perceptible color change is also produced in addition if the incidence and exit angles are simultaneously changed, for example from the range 0°-30° (see FIG. 3a) to incidence and exit angles, for example in the range 30°-60° (see FIG. 3b). The functional element 2 according to the invention is designed in such a way that in the case of such a change from a first incidence angle to a second incidence angle, a second color impression is perceived instead of the first color.

[0220] The profile shape and / or the relief depth and / or the grating period of at least the first relief structure 13 are further preferably selected such that for a second angle of incidence different from the first angle of incidence the coloured appearance of the light directly reflected at the first sub-area or the light directly transmitted through the at least one metal layer 12 changes differently.

[0221] In particular, a first color impression appears in direct reflection for a first angle of incidence and a second color impression appears in direct reflection for a second angle of incidence, in particular starting from a normal 400 perpendicular to the base surface of the relief structure 13, the first angle of incidence being selected from the range 0°-30° and in particular the second angle of incidence being greater than the first angle of incidence by a value selected from the range 10°-45°. This allows a defined color change or color gradient effect when tilted. In the case of reflected light observation and / or transmitted light observation, in particular at the first or second angle of incidence a different, relatively stable color impression thus appears in direct reflection to the human observer.

[0222] 4a and 4b show an exemplary embodiment of a functional element according to the invention, which has two first regions 211, 212 with in each case a relief structure 13 and a metal layer 12 arranged on the relief structure. Furthermore, the functional element can optionally have, preferably, a polymeric dielectric layer, which is arranged on the side of the metal layer facing the viewer. In both first regions 211, 212, the relief structure has the same profile shape, relief depth and grating period. If the functional element 2 of FIG. 4a is observed at a first angle of incidence, thus the same first color impression is perceptible for the viewer in both first regions 211, 212 and the functional element 2 appears monochromatic. If the functional element 2 is observed at a second angle of incidence, as is represented diagrammatically in FIG. 4b, a second color impression can be perceived for both regions 211, 212. This second color impression is different from the first, gold or copper color impression and is further different for both regions. Thus, the observer perceives, for example, a green star in the first region 212 in front of the first region 211 having a magenta background. This second color impression depends in particular on the azimuth angle of the relief structure 13. Thus, for example, one first region 212 may have an azimuth angle of 0° to 90°, in contrast a further first region 211 may have an azimuth angle rotated or different by at least 15°, preferably 30°, even more preferably 45°.

[0223] For example, for illustration in this regard in the embodiment example of the functional element 2 according to Fig. 4c, the K-shaped first region 212 is designed to have an azimuth angle of 45°, while the region 211 surrounding the K-shaped area is designed to have an azimuth angle of 0°. Since the two first regions 211, 212 have the same profile shape, relief depth or grating period, the same first color print is formed in direct reflection in both first regions at the first incidence and exit angles. The advantage here is that this color gradient effect is structure-based and therefore perfectly coincides with other structure-based effects.

[0224] In the case of a third angle of incidence different from the first and second angles of incidence, preferably greater than or equal to 60° with respect to the normal 400, an optical appearance different from the optical appearance of the first and second angles of incidence appears, preferably due to light diffracted into a first diffraction order in at least one first region 21, as shown by way of example in FIG. 4d.

[0225] According to a preferred embodiment of the functional element according to the invention, the grating period Λ and / or the profile shape and / or the relief depth t of the first relief structure 13 are designed in such a way that, for an incidence or observation angle of 0° to 30°, at least one first region 21 has a reflectance of irradiating light in at least 75% of the wavelength range from 400 nm to 500 nm that is at least 10% lower than the reflectance in at least 75% of the wavelength range from 525 nm to 700 nm.

[0226] The profile shape and / or the relief depth t of the first relief structure 13 are preferably designed such that at least one first region 21 has a reflectance of irradiated light in at least 70% of the wavelength range from 400 nm to 500 nm that is at least 15% lower than the reflectance in at least 70% of the wavelength range from 525 nm to 700 nm, more preferably at least one first region 21 has a reflectance of irradiated light in at least 90% of the wavelength range from 400 nm to 500 nm that is at least 15% lower than the reflectance in at least 90% of the wavelength range from 525 nm to 700 nm, and even more preferably at least one first region 21 has a reflectance of irradiated light in at least 90% of the wavelength range from 400 nm to 500 nm that is at least 20% lower than the reflectance in at least 90% of the wavelength range from 525 nm to 700 nm.

[0227] In addition to the preferred design of the profile shape and / or the relief depth t and / or the grating period Λ of the first relief structure, it is preferred that the at least one first region 21 has a direct reflectance of irradiated light of more than 30%, preferably more than 40%, preferably more than 50% in at least 90% of the wavelength range from 525 nm to 700 nm in order to prevent the first color impression from appearing too dark.

[0228] The wavelength range from 400 nm to 500 nm corresponds in particular to the wavelength range of violet and blue light, and the wavelength range from 525 nm to 700 nm corresponds in particular to the wavelength range of green, yellow, orange and red light. The above-mentioned design of the at least one first region 21, in particular with regard to the profile shape and / or the relief depth t and / or the grating period Λ, therefore has the consequence that the proportion of reflected light of blue and / or cyan color is smaller than the proportion of reflected light of the remaining wavelength range visible to the human eye, preferably the wavelength range from 400 nm to 700 nm. Thereby, the first color impression appears to the observer in a golden or coppery shade in direct reflection.

[0229] Figures 5a and 5b show the reflectance spectrum of a relief structure (continuous lines) of a first area 21 of a functional element 2 according to the invention in order to explain what has been said above. The dotted line corresponds to an exemplary third area 23 which produces a particularly dark or black coloration for direct comparison. In Figure 5a the spectrum according to the measured original data is plotted, whereas in Figure 5b it is plotted with a polynomial 5. The spectrum fitted with the powers is represented. The measurements were all carried out in the wavelength range 400 nm to 700 nm (x-axis) and the values ​​obtained for reflectances between 0% and 100% are plotted on the y-axis.

[0230] It can be clearly seen that the reflection spectrum of the first region 21 has a higher reflectance compared to the third region 23. Moreover, the reflectance of the first region 21 in the wavelength range of 525 nm to 700 nm is higher than the reflectance in the wavelength range of 400 nm to 500 nm. The parameter ΔR represents the above-mentioned preferred difference between the wavelength ranges and is illustrated by horizontal and vertical dashed lines for better orientation.

[0231] According to a preferred embodiment of the functional element 2, the profile shape of the at least one first relief structure 13 is designed asymmetrically in the x-direction and / or in the y-direction, as shown, for example, in figure 1 or 2. In other words, the profile shape of the at least one first relief structure 13 is designed asymmetrically in the x-direction and / or in the y-direction. Furthermore, it is advantageous if the profile shape varies continuously or stepwise, in particular over the relief depth t.

[0232] The excitation field is advantageously localized by the asymmetric profile shape, e.g. more strongly at the narrow tip of the relief structure 13. This makes the resonance and absorption more pronounced. Furthermore, the excitation of plasmons is different on the two sides of the asymmetric profile shape, so that the incident light produces different effects depending on which surface the light is emitted on.

[0233] Symmetric profile shapes are, for example, sinusoidal, rectangular, binary, etc. In other words, a symmetric profile shape has mirror symmetry if the base surface is used as a mirror surface. Here, the profile shape remains the same in this mirroring, and the relief structure is shifted by half the grating period Λ. According to the invention, an asymmetric profile shape does not have mirror symmetry in the plane spanned by the base surface.

[0234] Preferably, the value of the grating period Λ of the at least one first relief structure 13 in the x-direction and / or the y-direction applies: Λ<300 nm, preferably Λ≦280 nm, even more preferably Λ≦260 nm. Even more preferably, the value of the grating period Λ of the at least one first relief structure 13 in the x-direction and / or the y-direction is selected in the range from 150 nm to 260 nm, preferably from 180 nm to 250 nm.

[0235] Furthermore, it is advantageous that t<0.7Λ, preferably t≦0.6Λ, applies to values ​​of the relief depth t of the at least one first relief structure 13 in the x-direction and / or y-direction. It is also advantageous that t>0.2Λ, preferably t≧0.3Λ, applies to values ​​of the relief depth t of the at least one first relief structure 13 in the x-direction and / or y-direction.

[0236] Furthermore, the preferably asymmetric profile shape of the at least one first relief structure 13 can be selected such that the height and recess width of the at least one first relief structure 13 relative to a distance t / 2 from the base surface is at least 60% of the grating period, preferably at least 70% of the grating period, and / or at most 40% of the grating period, preferably at most 30% of the grating period.

[0237] In particular, the steepness of the flanks of the at least one first relief structure 13 relative to the distance t / 2 from the base surface can have a value in the range from 60° to 90°, preferably in the range from 70° to 85°.

[0238] The steepness of the flanks of the at least one first relief structure 13 for each distance starting from the base surface between 25% of the relief depth and 75% of the relief depth is preferably selected to have a value selected from the range of 40° to 90°, preferably 50° to 85°.

[0239] Furthermore, it is advantageous to select the steepness value of the flanks of the at least one first relief structure 13 to have a value selected from the range of 0° to 50°, preferably 0° to 40°, for each distance between 0% and 25% of the relief depth and / or between 75% and 100% of the relief depth, in each case starting from the base surface.

[0240] At least one first relief structure 13 is preferably formed as a 2D diffraction grating, preferably as a cross grating and / or as a hexagonal grating, or as a more complex 2D diffraction grating. By more complex 2D diffraction grating is meant, for example, a 2D diffraction grating with preferably slight stochastic variations of the grating period. Furthermore, it also means a 2D diffraction grating that is periodically arranged over a length of at least four times the locally present grating period, and at the same time randomly arranged over a length of more than 100 μm. A 2D grating has a series of bumps and depressions in the x and y directions. That is to say, one first relief structure 13 is preferably not designed as a line grating, but is therefore designed as a 1D grating.

[0241] In the case of a cross or hexagonal grating, the grating period Λ of the high-low arrangement for both directions is preferably selected from the ranges specified above, where the grating period is preferably the same in the x and y directions, but it is also possible that the grating period is different in the two spatial directions.

[0242] Furthermore, it is also possible that the periodic variation of the at least one first relief structure 13 is at least partially superimposed by a random and / or pseudo-random variation.

[0243] Furthermore, it is also possible for the periodic variation of the at least one first relief structure 13 to be superimposed, at least in areas, on a microstructure, in particular a Fresnel lens and / or a Fresnel freeform surface, and / or a micromirror and / or a blazed grating, in particular with a period of more than 5 μm, and / or a computer-generated hologram (CGH) structure.

[0244] Thus, in FIG. 6a, it is shown by way of example that at least one relief structure 13 consisting of hills and depressions can be superimposed on a microstructure such as a blazed grating. Here, by way of example, a functional element 2 representing an apple is shown in FIG. 6b. Due to the microstructure, for example a Fresnel freeform surface, areas that substantially protrude from the surface or bounce back behind the surface are clearly recognizable. Here, in addition to the optical effects of the at least one first relief structure 13, such as a stable color impression, a color gradient effect and a "latent image effect", it is possible to simultaneously realize optical effects of the microstructure itself or to combine the optical effects of both structures. Thus, for example, areas with an optical bulging effect that substantially protrudes from the surface or bounces back behind the surface due to a microstructure, for example a Fresnel freeform surface, are not perceived achromatically, but as this kind of golden or copper-colored optical bulging effect.

[0245] In particular when a blazed grating structure with a grating period of more than 5 μm, i.e. with an inclined macroscopic surface, is superimposed by a first relief structure 13, the angle of the inclined macroscopic surface relative to the base surface results in a corresponding inclination of the first relief structure 13, whereby this thus combined relief structure 13 produces a color impression with a larger observation angle range. A color gradient of the combined relief structure can also be realized in the case of the superimposition of the first relief structure 13 with a Fresnel lens structure or a Fresnel freeform surface with varying lateral angles.

[0246] According to a preferred embodiment of the present invention, the functional element 2 has at least one second region 22, and at least one second relief structure 15 is formed in the at least one second region 22. The at least one second relief structure 15 is a relief structure preferably selected individually or in combination and / or superimposed from diffractive relief structures, holographic relief structures, in particular 2D, 2D / 3D or 3D holograms, matt structures, micromirror surfaces, reflective facet structures, refractive, almost achromatic microstructures, blazed gratings, preferably with a grating period of more than 5 μm, lenses, microlens grids, binary random structures, binary Fresnel shaped microstructures.

[0247] In this way, the at least one second relief structure 15 is designed such that, in particular under diffuse lighting, the at least one second region 22 appears preferably in a silvery color and / or in the inherent color of the metal in which the at least one second region is arranged and / or in which the at least one second relief structure 15 is engraved.

[0248] According to a preferred embodiment of the present invention, the functional element 2 has at least one third region 23, in which at least one third relief structure 16 is formed. The at least one third relief structure 16 is in particular a relief structure consisting of a grating structure with a grating period Λ of 300 nm or more and a relief depth t of 150 nm or more. The at least one third region 23 preferably has a layer of a high refractive index material. The at least one third region 23 is preferably designed to have a red or dark, essentially black, first color impression in direct reflection or transmission.

[0249] Since optical effects such as the color impression of the different areas are produced substantially by the structure, in particular the at least one first area 21, the at least one second area 22 and the at least one third area 23 can be positioned in precise register with respect to one another, such that the placement of an additional varnish layer for the colored design can be omitted.

[0250] According to one embodiment of the invention, at least one first region 21, at least one second region 22, at least one third region 23, or at least one of the first, second or third regions 21, 22, 23, has a patterned shape. An area can be shaped, for example, in the shape of a letter, a number, a symbol, a geometric figure or a motif. In particular, at least one first region 21 can be designed as a mini-text or micro-text.

[0251] Furthermore, it is also possible for the first and / or second and / or third regions 21, 22, 23 to be arranged as a plurality of pixels. The pixels can also be designed as a circle, a square, a hexagon, a motif shape or another bulky shape. The pixels can also have an elongated shape, in particular a line shape.

[0252] In at least one of the spatial directions, preferably in the x direction (P x ) and y-direction (P y The maximum extent of a pixel in the x-direction and / or y-direction (P) is preferably less than 300 μm, preferably less than 100 μm, more preferably less than 10 μm, more preferably less than 5 μm, and even more preferably less than 3 μm. Furthermore, a pixel may have an extent (P) of more than 1 μm, preferably more than 1.5 μm, in the x-direction and / or y-direction. x ,P y Advantageously, the structure is formed of

[0253] Furthermore, as shown in Figures 7a and 7b, it is possible to design the at least one first region 21 to be arranged in at least two, preferably at least three, more preferably at least five zones. The zones are preferably designed to be arranged at least 300 μm, preferably at least 1000 μm, apart from each other in the x-direction and / or y-direction, so that they are perceived as being apart from each other by the human eye. In particular, one of the zones, preferably each, is arranged at least 300 μm apart from each other in at least one spatial direction b1 and at least one first zone region formed smaller than 2 mm, preferably smaller than 1 mm, more preferably smaller than 0.7 mm, wherein it may be advantageous for the at least one first zone region to occupy at least 20%, preferably at least 30%, more preferably 50% or more of the surface area of ​​the individual zone.

[0254] Also, at least one zone is in at least one spatial direction b 2 It is also possible to have at least one second zone region formed larger than 2 mm, preferably larger than 3 mm, more preferably larger than 5 mm, and in particular, the surface area of ​​the second zone regions of all zones is at least 20 mm in total. 2 Larger, preferably 30mm 2 Larger, preferably 50mm 2 Furthermore, it is also possible to reduce the extent of at least one zone in one spatial direction, preferably by tapering continuously or in steps.

[0255] FIG. 7b shows an example of said embodiment, where a continuous tapering zone in the shape of a sun spot of at least one first area 21 is integrated into the design of at least one second area 22. The tapering zone leads to the second area 22 designed as a temple. Further structures constituting the second area 22 generating a radial achromatic movement effect depending on the inclination angle are arranged in perfect register between the tapering zones. Furthermore, the functional element 2 is also designed in such a way that the background of the temple is formed in the first area 21. Due to such a careful combined design of the first area 21 and the second area 22, the achromatic movement effect and the small areas appearing gold or copper are very easily detected by the human eye.

[0256] Furthermore, as in the design example according to FIG. 8b, at least one first region 21 can be bordered or even completely surrounded by at least one third region 23, the at least one third region 23 being within a range b in one of the spatial directions selected from the range of 30 μm to 1 mm, preferably 50 μm to 300 μm, more preferably 50 μm to 150 μm. 23 In this way, the at least one third region 23 forms a contour-like frame bordering the at least one first region 21. This is particularly advantageous in the case of mini- or micro-text, as can be seen in Fig. 8a. The optical effects in the first, second and third regions 21, 22, 23 preferably have as different a chromaticity as possible and therefore as good an optical contrast as possible with one another.

[0257] In a further embodiment depicted in FIG. 8c, at least one first region 21 can be framed within or completely surrounded by at least one second region 22, where the at least one second region 22 has a spatial dimension selected from the range of 30 μm to 1 mm, preferably 50 μm to 300 μm, more preferably 50 μm to 150 μm. 22 In particular, the at least one second region 22 can here be bordered in area or completely surrounded by the at least one third region 23, and the at least one third region 23, in particular its area b 23 , can be designed in the same manner as in the previous section. Furthermore, at least one second region 22 can have a micro-texture or nano-texture.

[0258] Since the optical effects of the different regions, such as color impressions, are substantially produced by the structure and not by additional printed color layers, in particular the at least one first region 21, the at least one second region 22 and the at least one third region 23 can be positioned in precise register with respect to one another.

[0259] This allows in particular color schemes with self-explanatory design elements arranged in perfect register, such as flags, which can be easily supplemented by further structure-based effects.

[0260] The functional element 2 shown in FIG. 9 is intended to illustrate the above. A functional element 2 is shown having at least one first relief structure 13 in at least one first region 21 and also a metal layer 12 arranged in at least one sub-region of the first relief structure 13. Optionally, the functional element 2 has a preferably polymeric dielectric layer on the side of the metal layer 12 facing the observer. Furthermore, the functional element 2 further comprises two third regions 23. The two third regions are designed to generate different first color impressions in terms of profile shape, relief depth and grating period. In this example, the two third regions 23 and the one first region 21 are arranged in the shape of a flag, the regions being designed to appear black, red and gold, respectively. The observer can now intuitively recognize the flag of the Federal Republic of Germany.

[0261] FIG. 10 shows a further embodiment example, in which the at least one first relief structure furthermore has a color impression in transmitted light in the at least one first region 21. This is due to the increased transmission through the metal layer 12 arranged on the relief structure 13 as a result of the plasmon excitation made possible by the relief structure. The relief structure 13 according to the invention is integrated in this design not only in the eyes of the owl but also in the moon. In contrast, the body of the represented owl has a relief structure of a third region that appears reflective and dark. Effects based on other structures, for example Fresnel freeform effects or even diffraction grating structures, are preferably also integrated into the rest of the design.

[0262] On the left side of Figure 10, the design is shown for reflected light viewing and diffuse lighting. On the right side of Figure 10, functional element 2 is shown for vertical transmitted light viewing, where the areas with other structure-based effects are only visible as dark borders around the owl and moon. When functional element 2 is tilted, the color impression in transmitted light of both relief structures changes to magenta.

[0263] According to a further embodiment of the functional element 2 according to the invention, a plurality of microlenses can be arranged in a grid above the at least one first area 21. In particular, the microlenses are arranged such that the at least one first area 21 is perceived by the observer as magnified. In other words, the at least one first area 21 is in the focal plane of the microlenses. For illustration purposes, an exemplary embodiment of the functional element 2 according to the invention according to Fig. 1 or Fig. 2 is shown in Fig. 11a, where another plurality of microlenses is arranged above the functional element 2, so that a drop-shaped item of the displayed image information is revealed to the observer.

[0264] 11b, in particular, it is shown here how at least one first region 21 and, for example, at least one third region 23 are arranged in sub-regions such that the sub-regions reveal a plurality of micro-images or moiré icons arranged in a grid, in particular, these micro-images or moiré icons are now arranged in alignment with a plurality of micro-lenses arranged in a grid.

[0265] Moreover, as shown in enlarged view in FIG. 11c, the sub-area is in particular composed of a number of pixels, the pixels being designed as already mentioned above with respect to their spatial extent (P x and P y ).

[0266] Depending on the desired coloring design, the sub-regions are composed of a plurality of pixels formed in at least one first region 21, at least one second region 22, and / or at least one third region 23. For example, as shown in Fig. 11b, micro-images composed of pixels having light white or silver coloring, dark gray or black coloring, and / or gold or copper coloring are possible here.

[0267] The sub-areas can also be designed throughout the pixel arrangement such that a gradual transition is achieved from the increased arrangement of pixels constituting at least one first region 21 to the increased arrangement of pixels constituting at least one second area 22. A perceptible gradual transition from a golden or copper appearance to a silver appearance is hereby possible.

[0268] Furthermore, by combining the variants of the previous embodiment, it is possible to design a gold or copper impression of lighter sub-areas, close to a silvery shade. This can be achieved by arranging the pixels that do not constitute the at least one third region 23 as a mixture, preferably a probability distribution, of the pixels that constitute the at least one first region 21 and the at least one second region 22.

[0269] Alternatively or additionally, the motif of the micro-image motif or the motif of the moiré icon can be composed in one zone of pixels having a silver reflective appearance and pixels having a dark grey to black appearance, and in another zone of the motif of pixels having a gold or copper appearance and pixels having a dark grey to black appearance. In other words, a region of the motif of the micro-image motif or the motif of the moiré icon can be composed of pixels constituting at least one second region 22 and pixels constituting at least one third region 23, and in another region of the motif of pixels constituting at least one first region 21 and pixels constituting at least one third region 23. Multi-coloured designs of the functional element 2 are possible here, for example where a gold or copper transfer effect and a silver transfer effect are present in the security element 2 spatially separated from one another.

[0270] Fig. 12 shows a further embodiment example of a functional element 2 according to Fig. 11a. This functional element 2 has the already mentioned sub-areas consisting of a plurality of pixels consisting of the first, second and / or third areas 21, 22, 23 formed to represent the number "5". Furthermore, a plurality of microlenses are also arranged in a grid in the central part, so that the sub-area arranged therein is enlarged. At least one glazing color layer 14 formed in a star shape is now additionally arranged, in particular above the at least one first, second and / or third area 21, 22, 23 and below the plurality of microlenses. Regarding the embodiment and effect of the glazing color layer, reference is made to the above description.

[0271] Figure 13 shows a further embodiment variant of a functional element 2 according to the invention, for example according to figure 1 or 2. According to this embodiment variant, a motif is formed by a number of pixels constituting at least one first region 21 and a number of pixels constituting at least one third region 23. In other words, the functional element 2 represents a greyscale image, in particular a halftone image, or a monochromatic image. The greyscale is achieved by halftones by a distribution of pixels, the areas which appear dark are formed by the pixels constituting the third region 23 and the areas which appear light are formed by the pixels constituting the first region 21. The range of pixels P x or P y Please refer to the above description regarding this.

[0272] The functional element 2 according to the invention further provides the effect of having a first color effect in direct reflection or zero diffraction order due to its design compared to a conventional grayscale image. In particular, the functional element 2 provides a further surprising latent image effect in the case of strong tilts, especially at least in the first region 21. The grayscale image can furthermore, preferably completely, be bordered by a region of the functional element 1 with a further structure-based effect. For example, the grayscale image can be surrounded by a moving effect of thin lines that ends at the outer contour of the grayscale image, so that the observer's attention can be directed to this grayscale image.

[0273] Figure 14 shows a further embodiment of a functional element 2 according to the invention, for example according to figure 1. Here too the functional element 2 has at least one first relief structure 13 in at least one first region 21. Furthermore, a metal layer 12 is arranged in at least one sub-area of ​​the first relief structure 13 and optionally a preferably polymeric dielectric layer is arranged on the side of the metal layer 12 facing the viewer.

[0274] According to this example embodiment, the at least one first region 21 can be arranged in a first electrode layer. In particular, the first electrode layer can be arranged in or used in a reflective display. The first electrode layer can include further layers or functional elements, such as, for example, electrically conductive connection parts and / or electromagnetic shields and / or heat shields and / or light shields and / or circuits.

[0275] The first electrode layer has an optical effect produced by at least one first region 21 .

[0276] Furthermore, it is advantageous if a switchable layer 30, for example an electrochromic layer or a liquid crystal layer or a PDLC (polymer dispersed liquid crystal) layer, is arranged on top of the first electrode layer. The switchable layer 30 is characterized in that its appearance can be changed by the application of a voltage. In particular, when no voltage is applied, for example in the case of a PDLC layer, it appears cloudy to the observer, or as long as a voltage is applied it appears transparent.

[0277] Furthermore, a second electrode layer can be arranged on top of the first electrode layer and / or the switchable layer 30. The second electrode layer is preferably designed to be transparent or semi-transparent and / or transparent and / or has a transmittance of at least 50%, preferably at least 75%, more preferably at least 90%, especially in the wavelength range from 400 nm to 700 nm. Examples of such transparent second electrode layers include printed PEDOT:PSS layers or structured, preferably microstructured, metal layers that appear transparent to the human eye.

[0278] The first electrode layer is advantageously arranged below the second electrode layer, in other words on the side of the second electrode layer facing away from the viewer, and in particular the switchable layer 30 is arranged between the first and second electrode layers.

[0279] The properties of the at least one first region 21 can hereby be advantageously integrated into a reflective display. In particular, the optical effect of the switchable layer 30 can be combined with the color effect of the lower electrode layer. Thus, in the case of a reflective display having a switchable layer 30, e.g. a PDLC layer, the gold or copper impression of the first electrode layer becomes visible, or at least becomes more visible, in particular in sub-regions of the display which switch from cloudy to transparent upon application of a voltage (labeled "on" in FIG. 14). However, when no voltage is applied to the reflective display (labeled "off" in FIG. 14), the at least one first region 21 is substantially invisible, or at least only weakly visible.

[0280] In this way, a functional element 2 of a reflective display is obtained, which is substantially only visible to the observer as long as a corresponding voltage is applied to the reflective display.

[0281] Furthermore, the switchable layer 30 may also contain a dye or be dyed, thereby providing a colour filter function in addition to the optical switching function, with the added advantage that the appearance of the switchable layer when a voltage is applied changes from the colour of the dye to the gold or copper colour of the bottom electrode layer when a voltage is applied.

[0282] The pigmentation level and / or volume percentage of dye in the switchable layer 30 is preferably less than 15%, preferably less than 10%, more preferably less than 5%. The dye in the switchable layer 30 is preferably a soluble dye or an insoluble nanoparticle.

[0283] Figures 15a to 15e show a further embodiment of a functional element 2 according to the invention, for example an embodiment according to figure 1. In this embodiment, the functional element 2 is preferably described as a sensor element. The functional element 2 or the sensor element can be used for example in a sensor as product. The mode of operation of the functional element 2 is for example to detect a specific substance. Figures 15a to 15d are schematic cross-sectional views of different possible embodiments of a functional element 2 according to the invention, and Figure 15e is a schematic top view of the functional element before (left side), during and / or after contact (right side) with the substance to be detected.

[0284] Here too, the functional element 2 has at least one first relief structure 13 in at least one first region 21. The at least one first relief structure 13 is not represented in Fig. 15a-15d for simplicity. Furthermore, a metal layer 12 is arranged in at least one sub-area of ​​the first relief structure 13 and optionally in at least one sub-area of ​​the metal layer 12, preferably a polymeric sensor layer 17, arranged on the side of the metal layer 12 facing the observer. In particular, the region of said sub-area that is brought into contact with the medium with the substance to be detected forms the sensor region. The sensor layer 17 changes its refractive index and / or absorption coefficient when in contact with a sufficient amount of the substance to be detected. This changes the color impression perceptible by the human eye. Due to the increased absorption of the dye at the surface of the at least one metal layer 12 with the first relief structure 13, this change in color impression is already perceptible when the concentration of the substance to be detected is relatively low. This enhancement mechanism is called plasmon-enhanced absorption. The change in the color impression perceived by the human eye is much greater here compared to the metal layer 12 with the sensor layer 17 without the at least one first relief structure 13. This variable absorption behavior can be reversible or irreversible.

[0285] Optionally, a further, preferably dielectric, contrast layer 18 can be provided, which covers the sub-area of ​​the sensor facing the observer, in which the at least one first relief structure 13, the metal layer 12 and the sensor layer 17 are all arranged. The function of this contrast layer 18 is to protect the covered partial areas of the sensor layer 17 from contact with the substance to be detected, so that these areas do not show a change in color impression caused by the substance to be detected. This makes the contrast between these different areas particularly perceptible to the human eye.

[0286] FIG. 15a shows the sensor element 2 before detection and FIG. 15b shows the sensor element 2 during and / or after contact with a substance to be detected. The contrast layer 18 preferably has a refractive index close to that of the medium containing the substance to be detected. The refractive index of the contrast layer 18 preferably differs from that of the medium containing the substance to be detected by at most ±10%, more preferably at most ±5%, more preferably at most ±2%. For example, if the substance to be detected is water (refractive index n H2O ≒1.33), Teflon (registered trademark) (refractive index n Teflon ≒1.31), PVDF polyvinylidene fluoride (refractive index n PVDF ≒1.42), or magnesium fluoride MgF 2 (Refractive index n MgF2 ≈1.38) is also a possible material for the contrast layer 18.

[0287] Fig. 15e shows the sensor function in a schematic top view, where the contrast layer 18 is designed in such a way that the area of ​​the sensor layer 17 in the shape of a lightning bolt is not covered. The functional element 2 represented on the left side of Fig. 15e shows the state before the functional element 2 comes into contact with the substance to be detected. The lightning bolt is not perceptible or is barely perceptible. The functional element 2 represented on the right side of Fig. 15e shows the state during the contact of the functional element 2 with the substance to be detected. Due to the change in the color impression the lightning bolt is clearly perceptible.

[0288] For example, the sensor layer 17 may consist of a dye embedded in a polymer matrix. Methyl orange, bromothymol blue or phenolphthalein are suitable as dyes for pH sensors, for example. In aqueous solutions, these show different colors depending on the pH. Phenolphthalein, for example, is transparent at pH values ​​below 8 and becomes magenta from pH values ​​of 9 onwards. At pH values ​​significantly below zero, the indicator changes colour to red-orange.

[0289] Depending on the sensor layer 17 or the dye in the sensor layer 17, different substances in gas or liquid can be detected. For example, gas NO 2 , reacts with perylene and changes the complex refractive index of this substance, which, if the gas concentration is sufficient, changes the color impression of the functional element 2. Perylene can be applied directly to the metal layer 12, for example by a PECVD process.

[0290] FIG. 15c shows a design of the functional element 2 for the sensor, in which a filtering transparent layer, in particular an open-hole layer 19, is additionally applied at least in the sensor area. In other words, on the side of the sensor layer 17 facing the observer, a filtering transparent layer, in particular an open-hole layer 19, is arranged. This filtering layer 19 is permeable to the substance to be detected present in the medium and prevents other substances present in the medium from reaching the sensor layer 17. This makes it possible to reduce or prevent undesired reactions of the sensor layer 17 with other substances also present in the medium. Optionally, the edges of the functional element 2 are provided with a further, preferably polymeric, sealing layer 20, which prevents the medium from leaking out of the edges of the functional element 2.

[0291] Figure 15d shows a further design, in which the medium is transported to the sensor area through a vertically running channel 24. The channel 24 may be formed as a microfluidic system. The channel 24 may optionally, and preferably, be sealed with a polymeric sealing layer 20. The sealing layer 20 is preferably formed to be transparent.

[0292] The production of the functional element 2, in particular the sensor element, can be realized as follows: At least one first relief structure 13 can be created by known methods, such as holographic two-beam exposure or electron beam lithography, on a glass substrate. A nickel shim with the at least one first relief structure 13 can be obtained from this according to the known state of the art by a galvanic copying process. The nickel shim is replicated according to known methods and then the at least one first relief structure 13 can be produced in a flexible film, for example in a roll-to-roll process, such as thermal or UV replication.

[0293] It can be advantageous for the functional element 2, preferably a sensor element, inter alia, if the at least one first relief structure 13 is realized on a rigid substrate, for example a glass or quartz substrate. This allows for easier handling of the liquid medium, for example. For this reason, the at least one first relief structure 13 can be replicated in a UV replication process directly from the nickel shim onto a rigid substrate, such as a glass or quartz substrate. Known processes for this use so-called sol-gel materials, for example ormocells, which are applied in liquid form to the rigid substrate. The nickel shim is then placed on the rigid substrate, for example a glass or quartz substrate, so that a thin film of sol-gel material remains between the rigid substrate and the nickel shim. After this, the sol-gel material is cured by UV irradiation through the rigid substrate, for example a glass or quartz substrate, and the nickel shim is peeled off. A metal layer 12 can then be evaporated or sputtered in vacuum onto the surface of the cured sol-gel layer with the at least one first relief structure 13. The sensor layer 17 may then be applied as a thin layer onto the metal layer 12, for example by spin coating.

[0294] Further schematic embodiments of the functional element 2 are shown in Figures 16 and 17. In this embodiment, a transfer film is described as the functional element 2. The functional element 2 according to Figures 16 and 17 can have a design as described in Figure 1. Figure 17 is a schematic cross-sectional view of a transfer film. Figure 16 is a schematic top view on the transfer film, where the carrier layer 501 has already been peeled off from the transfer layer, so that at least one first relief structure 13 forms the side facing the viewer over the entire surface.

[0295] The transfer film comprises a carrier layer 501 and a transfer layer which is peelable from the carrier layer 501. The carrier layer 501 may comprise a separation layer 502. On the carrier layer 501 one or more further layers are arranged, preferably in the following order, which preferably form the transfer layer: a release layer 503, a replication layer 504 consisting of at least one first relief structure 13, a metal layer 12, a primer layer 506 and an adhesive layer 507.

[0296] The carrier layer 501 preferably consists of polyester, more preferably PET, and the separating layer 502 preferably consists of wax. The metal layer 12 is preferably formed of aluminium and is preferably vapor-deposited. Furthermore, the at least one first relief structure 13 of the functional element 2 is preferably arranged over the entire surface in the replication layer 504. The at least one first area 21 is arranged in the transfer layer, in particular over the entire surface, perpendicular to the plane spanned by the replication layer 504 in the viewing direction.

[0297] Representative methods for transferring the transfer layer include, for example, a hot stamp method and a cold stamp method.

[0298] FIG. 18 shows an embodiment of a product 1 consisting of a functional element 2. In this embodiment, a bottle label, for example, for a wine bottle, is described. The bottle label consists of a paper label for attaching to a bottle. This label includes, as a decorative layer, a decorative frame hot stamped on a paper label consisting of the transfer film described in FIG. 16 and FIG. 17. The transfer of the transfer layer is performed by a hot stamping method or a cold stamping method. The carrier layer 501 can be peeled off after the transfer of the transfer layer. The bottle label shown in FIG. 18 further has a decorative element stamped on the bottle label. The letters "WINE" are stamped on the paper label, for example, using gold foil as is customary in the industry, and the year "2021" is stamped, for example, using "silver foil" as is customary in the industry.

[0299] By silver foil is preferably meant an aluminized foil having no diffractive or refractive structures. Such foils are also called mirror foils. Furthermore, by gold foil is preferably meant an aluminized foil having no diffractive or refractive structures, with an additional, preferably yellow glaze layer arranged on the aluminum layer in the viewing direction.

[0300] Moreover, by way of example, the letters "IDLA" are imprinted with an aluminized transfer film having a diffractive matte structure. Such a foil is similar to the foils described in Figures 16 and 17, where instead of the relief structure according to the invention, the matte structure already described above is used.

[0301] You can also add prints to the label that can be placed next to, below, or above the stamped area.

[0302] The decorative frame depicted in Fig. 18 constituting a functional element according to the invention can perform two functions: on the one hand, it is an interesting decorative element that changes color depending on the viewing angle, and on the other hand, it simultaneously acts as a security element to prevent counterfeiting.

[0303] 19 shows the layer structure of a functional element according to the invention as a label film and / or a laminate film, which preferably has one or more of the following layers in the following order: carrier layer 501, primer layer 506, replication layer 504 consisting of at least one first relief structure 13, metal layer 12 and adhesive layer 507.

[0304] The carrier layer 501 preferably consists of polyester, more preferably of PET, and the adhesive layer 507 is preferably a low-temperature adhesive layer. The metal layer 12 preferably consists of aluminium and is preferably vapor-deposited. Furthermore, the at least one first relief structure 13 is preferably arranged over the entire surface in the replication layer 504.

[0305] A further embodiment of a product comprising a functional element 2 is shown in Fig. 20. This embodiment is, for example, a pharmaceutical packaging to which a label based on the label film and / or laminate film described in Fig. 19 is applied. The label shown in Fig. 20 is applied in the upper region of the packaging, in the area covering the hinged lid and the lower region of the packaging. For example, the characters "SECURE" are additionally printed on the label film and / or laminate film and the characters "ETRO-FP-" are additionally stamped on the packaging using silver foil as is customary in the industry.

[0306] The label placed on the packaging of Fig. 20 can fulfill the essential aspects of a security element and a decorative element. It therefore changes color depending on the viewing angle, drawing the observer's attention to itself. This makes it easy to recognize if the packaging has already been opened. In addition, the label also provides protection against counterfeiting.

[0307] Of course, the above embodiment variants of the functional elements 2 or of the products 1 can be combined with one another as desired and do not imply any limitation, especially in terms of their shape and combination. [Explanation of symbols]

[0308] 1 product 2. Functionality elements 10 Carrier Board 11 Window Area 12 metal layer 13 First relief structure 14 Glazing varnish layer 15 Second relief structure 16 Third relief structure 17 Sensor Layer 18 Contrast Layer 19 Filter Layer 20 Sealing layer 21, 211, 212 First Area 22 The Second Area 23 The Third Region 24 Channels 30 Switchable Layers 100 light sources 200 angle of incidence 300 Output angle 400 Base surface normal 501 Carrier layer 502 Separation layer 503 Peeling layer 504 Replication layer 506 Primer layer 507 Adhesive layer

Claims

1. A functional element (2) comprising at least one first relief structure (13) in at least one first region (21) and at least one metal layer (12) disposed in at least one sub-region of the at least one first relief structure (13), wherein the at least one first relief structure (13) has a height and a depression that vary periodically in the x and y directions, the heights are contiguous with each other with a grating period Λ smaller than the wavelength of light visible to the human eye, the minimum value of the depression defines a base surface, the at least one first relief structure (13) has a relief depth t, in the at least one first region (21), a first color impression is formed at a first angle of incidence, and a second color impression is formed at a second angle of incidence, the first angle of incidence is selected from the range of 0° to 30°, when there is a third angle of incidence in the at least one first region (21), an optical effect different from the first and second color impressions is formed, the third angle of incidence has a value of 60° or more, characterized in that the functional element (2).

2. The functional element (2) according to claim 1, wherein the second color impression is generated according to the azimuth angle, or the periodic variation of the at least one first relief structure (13) is at least partially superimposed by at least one of random and pseudo-random variations, or the periodic change of the at least one first relief structure (13) is at least partially superimposed on the microstructure, or the at least one first relief structure (13) is formed as at least one of a cross grid, a hexagonal grid, and a more complex two-dimensional grid, characterized in that the functional element (2).

3. Λ < 300 nm is applied to the value of the diffraction grating period Λ of the at least one first relief structure (13) in at least one of the x and y directions, or the value of the diffraction grating period Λ of the at least one first relief structure (13) in at least one of the x and y directions is selected from the range of 150 nm to 260 nm, or t < 0.7Λ is applied to the value of the relief depth t of the at least one first relief structure (13) in at least one of the x and y directions, or t > 0.2Λ is applied to the value of the relief depth t of the at least one first relief structure (13) in at least one of the x and y directions, and is characterized by the functional element (2). **Claim 4** The functional element (2) according to claim 1, wherein the profile shape of the at least one first relief structure (13) changes continuously or stepwise, or wherein the profile shape of the at least one first relief structure (13) is designed asymmetrically in at least one of the x and y directions, or the height and the width of the depression of the at least one first relief structure (13) with respect to the distance of t / 2 from the base surface are at least 60% of the lattice period or at most 40% of the lattice period, or a polymer layer is disposed above or below the at least one first relief structure (13), and is characterized by the functional element (2). **Claim 5** The functional element (2) according to claim 1, wherein the reflectivity of the irradiated light in at least 75% of the wavelength range of 400 nm to 500 nm of the at least one first region (21) is at least 10% lower than the reflectivity in at least 75% of the wavelength range of 525 nm to 700 nm, or wherein the reflectivity of the irradiated light is greater than 30% in at least 90% of the wavelength range of 525 nm to 700 nm for the at least one first region (21), and is characterized by the functional element (2). **Claim 6** The functional element (2) according to claim 1, wherein at least one of the dye and the luminescent substance is disposed in the at least one first region (21), or wherein at least one of the dye and the luminescent substance is disposed in the dielectric layer, and is characterized by the functional element (2). **Claim 7** The functional element (2) according to claim 1, wherein the functional element (2) has at least one second region (21), and at least one second relief structure (15) is formed in the at least one second region (21), or wherein the functional element (2) has at least one third region (23), wherein at least one third relief structure (16) is formed in at least one third region (23), or wherein the at least one first region (21) is designed to be disposed in at least two zones, and is characterized by the functional element (2).

8. The functional element (2) according to claim 7, wherein the first, second or third region (21, 22, 23) is arranged as a plurality of pixels, and the pixels are designed in a circular, square, hexagonal, motif shape or another coherent shape, or have an elongated shape, in particular a linear shape, functional element (2).

9. The functional element (2) according to claim 1, wherein the at least one first region (21) is arranged in a first electrode layer, and a second electrode layer is arranged on at least one of the first electrode layer and the switchable layer (30), functional element (2).

10. The functional element (2) according to claim 1, wherein the sensor layer (17) is arranged in at least one partial region of the metal layer (12) on the side of the metal layer (12) facing the observer, and at least one of the dye and the luminescent substance is arranged in the sensor layer (17), functional element (2).

11. The functional element (2) according to claim 7, wherein under the at least one first region (21) or second region (22) or third region (23), at least one frosting color layer is arranged in the region or over the entire surface in the viewing direction of the observer, functional element (2).

12. The functional element (2) according to claim 11, wherein the at least one frosting color layer is directly adjacent to the metal layer (12), or is spaced from the metal layer (12) by a dielectric intermediate layer, or the at least one frosting color layer has a total ink holdout dE of 50 to 270 from the at least one first region or the second region or from the third region (21, 22, 23), or the at least one frosting color layer has a darker color and the at least one first or second or third region (21, 22, 23) has a lighter color, or the at least one frosting color layer has a lighter color and the at least one first or second or third region (21, 22, 23) has a darker color, functional element (2).

13. The functional element (2) according to claim 7, wherein The at least one first region (21) or the at least one second region (22) has a total ink holdout dE of 50 to 270 from the at least one third region (23), or the at least one first region (21) or the at least one second region (22) has a lighter color compared to the at least one third region (23), a functional element (2) characterized by this.

14. The functional element (2) according to claim 7, the at least one first region (21) is arranged in small regions so as to show a plurality of micro-images or moiré icons arranged in a grid pattern, or the grid of the micro-images or moiré icons has a plurality of sub-grids, and within the sub-grids, the micro-images or moiré icons are arranged in a one-dimensional array of the micro-images or moiré icons or in a two-dimensional array of the micro-images or moiré icons, or the micro-images or moiré icons within the sub-grids are formed so that an optical effect assigned to the sub-grid is formed for each sub-grid, and these optical effects, in the grid of the micro-images or moiré icons, together reveal a combined optical effect or reveal separate optical effects existing adjacent to each other, or in order to obtain different optical effects for each sub-grid, the micro-images or moiré icons are formed with at least one different first region (21) or at least one second region (22) or at least one third region (23) or at least one grading color layer in front of or behind the at least one first region (21) or the at least one second region (22) or the at least one third region (23), a functional element (2) characterized by this.

15. A method for manufacturing the functional element (2) according to any one of claims 1 to 14, the at least one first relief structure (13) is arranged in at least one first region (21) of the functional element, the metal layer (12) is arranged in at least one sub-region of the at least one first relief structure (13), As a result, the at least one first relief structure (13) has periodic height variations in the x and y directions, the heights are continuous with each other at a grating period Λ smaller than the wavelength of light visible to the human eye, as a result, the minimum value of the recess defines the base surface, and the at least one first relief structure (13) has a relief depth t, in the at least one first region (21), a first color impression is formed in the case of a first angle of incidence, and a second color impression is formed in the case of a second angle of incidence, the first angle of incidence is selected from the range of 0° to 30°, when there is a third angle of incidence in the at least one first region (21), an optical effect different from the first and second color impressions is formed, the third angle of incidence has a value of 60° or more, a method for manufacturing a functional element (2).

16. The method according to claim 15, the polymer layer is arranged on the side surface of the at least one first relief structure (13) facing the observer, in particular, the polymer layer is arranged on the at least one first relief structure (13) over the entire surface or partially, or, at least one of the dye and the luminescent substance is arranged in the at least one first region (21) away from one of the surfaces of the at least one metal layer (12), or, the dielectric layer is printed or vapor-deposited on or under the at least one metal layer (12), or, the at least one glazing color layer is arranged at least in the region or over the entire surface, and the at least one glazing color layer is arranged under at least one of the at least one first region or the second region or the third region perpendicular to the plane extended by the functional element, a method for manufacturing a functional element (2).

17. A product (1), comprising the functional element (2) according to any one of claims 1 to 14, a product (1).

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