EP2240330B1 - Method for producing a microstructure - Google Patents

Description

The invention relates to a method for producing a microstructure on a carrier, a microstructure that can be produced in this way, and an article having such a microstructure.

Data carriers, such as valuables or identity documents, but also other valuables, such as branded goods, are often provided with security elements for the purpose of security, which permit verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction. The security elements can be embodied, for example, in the form of a security thread embedded in a banknote, a covering film for a banknote with a hole, an applied security strip or a self-supporting transfer element which is applied to a value document after its manufacture.

Security elements with optically variable elements, which give the viewer a different image impression under different viewing angles, play a special role, since they can not be reproduced even with high-quality color copying machines. For this purpose, the security elements can be equipped with security features in the form of diffraction-optically effective microstructures or nanostructures, such as with conventional embossed holograms or other hologram-like diffraction structures, as described, for example, in the publications EP 0 330 733 A1 or EP 0 064 067 A1 are described.

For some time, so-called Moire magnification arrangements are used as security features. The principle of operation of such Moire magnification arrangements is described in the article " The moire Magnifier ", MC Hutley, R. Hunt, RF Stevens and P. Savander, Pure Appl. Opt. 3 (1994), pp. 133-142 , described. Thus, in short, moire magnification refers to a phenomenon that occurs when viewing a raster of identical image objects through a lenticular of approximately the same pitch. As with any pair of similar rasters, this results in a moiré pattern, in which case each of the moiré fringes appears in the form of an enlarged and rotated image of the repeated elements of the image raster.

The publication WO 2006/034780 A1 deals with optically variable security elements for securing valuables having at least one piece of information and a translucent, optically variable layer disposed over the information. The information is formed by a layer sequence with a colored background printing layer and an intaglio printing layer printed over the background printing layer.

The publication WO 99/56964 A1 describes a method for producing security films for valuables, such as securities, in which a printing plate mounted in a printing press is imaged, so that areas of the printing form are ink-accepting. After inking the printing form so that a carrier sheet is printed.

In the publication EP 0 933 407 A1 are described special, in the flexographic printing processable security inks, which are applied with a flexographic printing system in the form of colored images on a paper sheet.

The publication WO 98/39163 A2 deals with security products such as banknotes and identity cards, which are provided with luminescent security elements which can be excited in an alternating electromagnetic field, and with a process for the production which, in particular, applies the required colors and substances to such a product in gravure printing.

On this basis, the object of the invention is to avoid the disadvantages of the prior art and, in particular, to provide an improved method for producing a microstructure on a carrier which can be used in the production of micro-optical moire magnification arrangements.

This object is achieved by the method having the features of the main claim. An article having such a microstructure and such a fabricable microstructure are given in the independent claims. Further developments of the invention are the subject of the dependent claims.

• ein Träger mit einer Reliefstruktur versehen, die Erhebungen und Vertiefungen aufweist, und bei der die Erhebungen und/oder Vertiefungen in Form der gewünschten Mikrostruktur angeordnet sind, wobei der Träger mit einer Prägestruktur mit Erhebungen und Vertiefungen versehen wird, die die Reliefstruktur bildet, oder auf den Träger eine Resistlackstruktur mit Erhebungen und Vertiefungen aufgebracht wird, die die Reliefstruktur bildet, wobei durch die Erhebungen und Vertiefungen der Mikrostruktur Mikrostrukturelemente mit einer Strichstärke zwischen 1 µm und 10 µm gebildet werden, und
• wird mit einem Druckwerkzeug ein Aufdruckstoff auf die Reliefstruktur übertragen, wobei die Viskosität des Aufdruckstoffs so gewählt wird, dass der Aufdruckstoff selektiv entweder im Wesentlichen nur auf die Erhebungen oder im Wesentlichen nur in die Vertiefungen der Reliefstruktur übertragen wird.

According to the invention, in a method of producing a microstructure on a support

• a carrier provided with a relief structure having elevations and depressions, and in which the elevations and / or depressions are arranged in the form of the desired microstructure, wherein the carrier is provided with an embossed structure with elevations and depressions, which forms the relief structure, or on the substrate is a resist coating structure with elevations and depressions is applied, which forms the relief structure, wherein the elevations and depressions of the microstructure microstructure elements are formed with a line thickness between 1 .mu.m and 10 .mu.m, and
• With the aid of a printing tool, an imprint material is transferred to the relief structure, wherein the viscosity of the imprint material is selected such that the imprint material is selectively transferred either essentially only to the elevations or essentially only into the depressions of the relief structure.

The chosen formulation, according to which the imprint material is selectively transferred either essentially only to the elevations or essentially only into the depressions of the relief structure, takes account of the fact that, for example, in the transfer of the imprint material into the depressions a slight toning film is used in practice can remain on the elevations of the relief structure, which does not affect the visual impression of the microstructure.

According to a preferred first aspect of the invention, a highly viscous imprint material is selectively transferred substantially only to the elevations of the relief structure using the printing tool. The high-viscosity printing material is advantageously transferred in a layer thickness which is smaller than the structural depth of the relief structures. The structure depth indicates the height difference between elevations and depressions in the relief structure. Preferably, the transferred layer thickness of the imprint material is less than 50%, more preferably less than 30% and most preferably even less than 15% of the structural depth of the relief structures.

Advantageously, the desired size and / or depth of the transfer areas, in which the imprint material is to be transferred to the elevations of the relief structure, predetermined. The hardness and surface roughness of the printing tool and the pressure when transferring the imprint material become then selected according to the desired size and / or depth of the transmission ranges. The pressure during transfer of the imprint material is expediently chosen so low that the imprint material is not squeezed. The imprint material can also be transferred substantially without pressure to the relief structure, wherein a predetermined distance between the printing unit and the relief structure is filled by the imprint material.

With particular advantage, the printing material is transferred in the offset printing process or in the flexographic printing process. In order to achieve the best possible results, it may be necessary to modify the standard offset printing process. For example, instead of a (rubber) blanket, a rubber roller can be used to allow in particular a shock and seam-free as well as more homogeneous and precise printing of the raised structures. Instead of a (rubber) blanket can in principle also be provided a metal roller, which then offers as a counter-pressure cylinder, a rubber roller. Instead of a printing plate, the use of a directly coated with a polymer cylinder in question to print shock and seamless. In further modifications can be dispensed with the impression cylinder. Instead, a direct coloring of the blanket or the rubber roller or generally the ink transfer cylinder is carried out over the entire surface or with a motif analogous to a high-pressure process. The curing can be carried out under inert gas in order to cure even extremely thin films well.

The printed, raised areas can be provided with protective lacquer to prevent re-dissolution in the following process.

In particular, a substance having a viscosity of between about 10 mPa * s and about 200 Pa * s, preferably between about 800 mPa * s and about 150 Pa * s at room temperature, is selected as the imprint material. It may also be possible to take into account any structural viscosity of the imprint material which may be present. Suitable printing materials are, in particular, a printing ink, preferably an offset printing ink, a radiation-curable, thermosetting or oxidatively drying printing ink, an adhesive, such as a highly viscous heat-sealing lacquer, and / or a water-activatable adhesive system. All printing materials can be pigmented with an effect and in particular contain luminescent pigments, thermochromic pigments, metal pigments and / or pearlescent pigments.

Particular preference is given to using imprint materials which have a certain stickiness, ie which are not tack-free. In the context of the present description, the term "non-tack-free" also means tacky in the sense of a sticky surface. The test can be carried out by the following test: Coated pieces of film of about 100 cm ² are stacked and loaded with a weight of 10 kg and stored at 40 ° C for 72 hours. If the pieces of film can then only be separated from one another with damage to the coatings, the coating must be considered tack-free.

If an adhesive is transferred as an imprint material, the relief structure can be brought into contact with a transfer medium after the transfer of the adhesive, and a transfer substance can be transferred from the transfer medium to the adhesive elevations of the relief structure. The transfer medium may be, for example, a coated film, a hot stamping film or a transfer roller. As transfer agents come in particular Colors, colored films, effect coatings, effect pigments, color, black or white pigments, dyes, effect layers or metallizations into consideration. Also, portions of a releasable hologram or other hologram-like diffraction structure may be selected as the transfer material and transferred to the adhesive-coated protrusions, as described in more detail below. The possibly still sticky adhesive layer with the transfer substance can be cured in a further step.

The relief structure can also be dusted directly after transferring the adhesive with a transfer substance, wherein any excess of the transfer substance can be removed after dusting, preferably by a non-contact method. In particular, blowing, sweeping, brushing, electrostatic removal or a combination of two or more of these methods may be considered. The transfer substance can also be optimized for removal with an electrostatic process. The unit which receives the surplus contactlessly can itself be mechanically cleaned. The excess can be at least partially returned to the process. The removal of the excess can also be done only after the curing of the highly viscous adhesive layer. Direct dusting is particularly suitable for metal pigments, for example for bronzing the embossing lacquer layer.

In an advantageous development of the method, after the transfer of the adhesive, a laminating film is laminated onto the relief structure. The laminating film serves on the one hand to protect the microstructure, on the other hand it allows to provide the surface of the laminating film opposite the microstructures with an adhesive layer which has a strongly adhering effect Embedding the layer sequence of carrier, microstructure and laminating in a security paper, document of value or the like allows.

By transferring the adhesive only to the elevations of the relief structure arise in the area between the laminating film and relief structure a variety of air-filled microcavities. These microcavities have the refractive index of the air contained (n = 1) and therefore have a large refractive index difference to the relief structure material (n≈1.5). As a result, a desired refractive or optically variable effect of the relief structures is obtained despite film lamination, as explained in greater detail below with reference to a few exemplary embodiments.

According to a further embodiment of the invention, a transfer material provided with an adhesive is transferred to the elevations of the relief structure as imprint material. As a transfer agent may in particular a color, a colored film, an effect, effect pigments, colored pigments, black pigments, white pigments, dyes, effect layers, a metallization, a portion of a hologram or a hologram-like diffraction structure or a farbkippendes element, in particular a farbkippendes thin-film element or a at least one liquid crystal layer-containing element can be selected.

In visually particularly attractive variants, the microstructure represents the motif image of a micro-optical magnification arrangement which generates a predetermined target image after the application of a viewing grid on the front side of a security element. The transfer substance additionally provides the micro-optical magnification arrangement with a backside effect, for example a backside hologram or a backside color-shift effect, as explained in more detail below.

In one embodiment of the invention, different high-viscosity printing materials, in particular different-colored or provided with different effect pigments imprint materials can be transferred.

In part, the elevations of embossed relief structures toward the edges have a gentle drop in height. In order to avoid possible unevenness in printing, before transferring the desired imprint material, a high-viscosity lacquer layer can be transferred, which compensates for the sloping edges of the elevations.

The elevations and / or depressions of the relief structure may also be rounded, provided with continuous transitions and / or with additional structures to support the method. For example, the elevations can be formed with a sharply delimited, upstanding edge region in order to limit the transferred imprint material even more to the area of the elevations. Such edge elevations are typically of the order of 1 μm. Optionally, the requirements for the viscosity of the imprint material can be reduced by this measure.

The elevations of the relief structure can also be provided with a microrelief structure, in particular with a diffractive microrelief structure for producing a hologram or a hologram-like diffraction structure. Alternatively, the elevations may also be provided with an achromatic, that is not colored, micro-relief structure. The elevations of the relief structure may also have a further superstructure, such as spikes, which hold the imprint material better on the surveys. Such a measure is particularly suitable for narrow lines to prevent squeezing of the imprint material

As a print material, a highly viscous resist, in particular a colored highly viscous resist can be selected. The use of such a resist coating is particularly suitable in conjunction with metallizations of the relief structure, since then the non-raised areas can be demetallized in a targeted manner.

For advantageously producing a microstructure with two microrelief structures visible from opposite sides with a common, perfectly matched negative pattern, the relief structure provided in the elevations with a microrelief structure is metallized over the entire area and a highly viscous resist lacquer is selectively transferred to the elevations of the metallized relief structure. After transfer, the relief structure is demetallized in regions not protected by resist coating, the relief structure is provided with an embossing lacquer layer after the demetallization step, and a further microrelief structure, in particular a diffractive microrelief structure, is embossed into the embossing lacquer layer.

Thereafter, the relief structure is metallized again, it is again a highly viscous resist coating selectively transferred to the elevations of the relief structure, the re-metallized relief structure is demetallized again in areas not protected by resist coating and the resist is optionally removed. If desired, a further high-viscosity ink can then be transferred to the elevations, so that the microrelief structures appear colored from the top side.

A demetallization step can be saved by selectively transferring a highly viscous resist to the elevations of the full-area metallized relief structure and providing this resist with the further microrelief pattern embossing. For this purpose, for example a thermoplastic resist is used. Then the relief structure is metallized again, it is again a highly viscous resist coating selectively transferred to the elevations of the relief structure. The re-metallized relief structure is then demetallized in areas not protected by resist, thereby removing both the first and second metallizations.

If larger contiguous demetallization surfaces are provided, preferably a soluble wash ink in the form of the desired demetalization area is printed on the relief structure before the metallization, and the wash paint after the metallization is washed off together with this by a solvent. Further details of such a washing process can the document WO 99/13157 be removed.

In addition, both during and after the embossing distance tracks for setting a defined distance and / or pressure when transferring the imprint material can be applied. The thickness of additional spacer tracks of clearcoat, which need not occur in the final product, can be chosen arbitrarily within wide limits. Depending on the available printing machine strips of defined thickness can facilitate the setting of a defined distance and / or pressure, which prevails between blanket and film. Such spacing tracks may, when at least partially taken into account in embossing, form adjacent, uniformly low lying and uniformly elevated areas.

Such areas without further structuring can also be advantageously used as indicator traces and recorded by measurement. Thereby For example, the application of paint and / or the pressure can be controlled according to a predetermined, maximum permissible toning film in the low-lying areas or the color saturation in the high-lying areas of the indicator tracks.

The imprint material can also be provided with particles of defined size, which prevent a crushing of the imprint material during transfer and thus also act as a kind of spacer.

In general, the use of relatively hard blankets in the method of the first aspect of the invention is advantageous because a hard blanket can reach harder lower points of the relief structure. Softer blankets, on the other hand, provide a smoother, lower pressure and can help offset imperfections in the overall system. Depending on the available equipment and the desired results, therefore, a suitable compromise for the hardness of the printing blanket must be found.

In general, the application of the high-viscosity printing material can also take place in several layers and / or in the form of a motif. As the uppermost layer, it is also possible to transfer a high-viscosity clearcoat. If toning is unavoidable in a motif, for example because of too small height differences or too large open areas, the desired view from above, ie from the direction of the raised structures, can avoid the problem by subsequently printing a low-viscosity opaque white formulation. The existing Tonungsfilm in the valleys is thereby covered in white, as explained in detail below in connection with the second aspect of the invention. For reverse consideration can also first the opaque white formulation are printed and then the high-viscosity printing ink.

If a relatively low-viscosity imprint material is to be transferred to the elevations of the relief structure, a pronounced intrinsic viscosity of the imprint material is advantageous.

Structural viscosity of a liquid or the imprint material in the sense of this invention is the property of exhibiting a lower viscosity at high shear forces. The stronger the shear that acts on the imprint material, the less viscous it is. Since the viscosity does not remain constant, this is classified as non-Newtonian behavior. The decrease in the viscosity results from a change in the structure of the imprint material, which ensures that the individual particles of the imprint material (for example polymer chains) are able to slide past one another better.

For example, printing inks are converted by mechanical action, such as stirring, shaking, trowelling or doctoring, of a solid or pasty consistency in a flowing consistency. In offset printing, this is done by the color splitting in the inking unit, reinforced by oscillating distributor rollers.

If the viscosity does not increase immediately after reducing the shear force, this behavior is called thixotropy. However, it is preferred to have an immediate increase in viscosity after application of the imprint, i. the imprint material should stand or not run immediately.

According to a likewise advantageous second aspect of the invention, the printing tool is an imprint material, in particular a low-viscosity imprint material selectively transferred substantially only in the recesses of the relief structure. In the selection of the low-viscosity imprint material, the surface tension of the imprint material is preferably also matched to the surface energy of the relief structure.

In this aspect, an imprint material having a viscosity of between about 3 mPa * s and about 1500 mPa * s at room temperature is chosen as the imprint material. Suitable printing materials are printing inks, in particular dye solutions, pigment dispersions, inks or else preferably low-viscosity liquid-crystal solutions. In the latter case, the depressions of the relief structure can also be formed with alignment structures for aligning liquid crystals. The dye solutions or pigment dispersions can optionally be binder-containing.

The transfer of the imprint material can also be carried out in two steps, wherein initially a low-viscosity printing ink or liquid crystal solution is transferred with a low binding body portion, which selectively flows into the recesses of the relief structure. Then, a solution having a high binder content is transferred, which fixes the ink or liquid crystal solution in the recesses of the relief structure.

In further variants of the invention, a low-viscosity adhesive or a low-viscosity resist can also be selected as the imprint material. All printing materials can be pigmented with effect, in particular luminescent pigments, thermochromic pigments, metal pigments and / or pearlescent pigments can be contained.

Also in this aspect of the invention may advantageously different low-viscosity printing materials, in particular different colors or with different effect pigments provided imprint materials are transferred to the wells.

The elevations of embossed relief structures are often surrounded by deep areas at their edges. If only a small amount of an imprint material is transferred, then the imprint material initially accumulates in the region of these edges. If this effect is desired for design reasons, for example, to provide the elevation pattern with a circumferential color edge, the imprint material can be transferred in such a small amount that it flows in the transmission only in the elevations immediately surrounding edge regions of the wells.

On the other hand, if the recesses are to be filled evenly, it may be expedient to transfer a small amount of a low-viscosity clearcoat material before the transfer of the desired imprint material, which fills the edge regions of the recesses which directly surround the elevations. In the subsequent transfer, the printing material then flows evenly into the recesses.

The elevations and / or depressions of the relief structure may also be rounded, provided with continuous transitions and / or with additional structures to support the method. In particular, the recesses may be formed with rounded transitions to the elevations in order to avoid the previously described effect of filling of the recesses starting from the edge regions.

In other embodiments, the bumps may also be provided with a lotus structure to produce low wettable bump surfaces. Such lotus structures reduce the contact area between the surveys and the imprint material to be transferred, so that it practically can not adhere to the surface of the surveys and flows more easily into the wells. The depressions of the relief structure can also be provided with a microrelief structure, for example a diffractive or achromatic microrelief structure.

Of course, the two aforementioned aspects of the invention can also be combined with each other. Thus, for example, in a first step, a first highly viscous imprinting substance can be selectively transferred substantially only to the elevations of the relief structure, and in a second step, a second low-viscosity imprinting substance can be selectively transferred substantially only into the depressions of the relief structure. With suitable process control, the low-viscosity printing material can also be selectively transferred first into the depressions and then the high-viscosity printing material selectively onto the elevations of the relief structure.

By the elevations and depressions of the microstructure microstructure elements are formed with a line thickness between about 1 .mu.m and about 10 .mu.m and / or preferably with a texture depth between about 0.5 .mu.m and about 20 .mu.m, preferably between about 1 .mu.m and about 10 .mu.m.

The process according to the invention can be used with particular advantage in the production of micro-optical moiré magnification arrangements, as described in the publications DE 10 2005 062 132 A1 and WO 2007/076952 A2 in the production of moiré-type micro-optical magnification assemblies as described in applications DE 10 2007 029 203.3 and PCT / EP2008 / 005173 and in the manufacture of modulo magnification arrangements as described in particular in the applications PCT / EP2008 / 005171 and PCT / EP2008 / 005172 are used become. All of these micro-optical magnification arrangements contain a motif image with microstructures which, when viewed with a suitably coordinated viewing grid, reconstructs a predetermined target image. As explained in more detail in the abovementioned publications and applications, a multiplicity of visually attractive enlargement and movement effects can be produced which lead to a high recognition value and a high security against forgery of the security elements equipped therewith. It should be emphasized, however, that the invention is not limited to these applications. Rather, the method described can be advantageously used in the production of other security elements, for example in the production of microtext printing on paper or film.

In an advantageous development of the invention, the microstructure forms a motif image, which is divided into a plurality of cells, in each of which imaged regions of a predetermined target image are arranged. The lateral dimensions of the imaged regions are preferably between about 5 μm and about 50 μm, in particular between about 10 μm and about 35 μm. In the micro-moire micro magnification arrangements first mentioned above, the imaged areas of the cells of the motif image each represent downsized images of the predetermined target image that are completely accommodated within a cell. In the moiré-type micro-optical magnification arrangements, the imaged areas of a plurality of spaced-apart cells of the motif image, taken together, each represent a reduced and optionally linearly imaged image of the target image whose extent is greater than one cell of the motif image. In the most general case, the magnification arrangement represents a modulo magnification arrangement in which the imaged areas of the cells of the motif image each represent by a modulo operation, not complete sections of the predetermined target image.

The security element preferably further comprises a viewing grid of a plurality of viewing grid elements for reconstructing the predetermined target image when viewing the motif image using the viewing grid. The lateral dimensions of the viewing grid elements are advantageously between about 5 μm and about 50 μm, in particular between about 10 μm and about 35 μm.

In the special case of a micro-optical moiré magnification arrangement, a motif image of a planar periodic or at least locally periodic arrangement of a multiplicity of micromotif elements is preferably applied as the microstructure. The lateral dimensions of the micromotif elements are advantageously between about 3 μm and about 50 μm, preferably between about 10 μm and about 35 μm. In addition, the opposite side of the carrier is expediently provided with a planar periodic or at least locally periodic arrangement of a plurality of microfocusing elements for moire-magnified viewing of the micromotif elements of the motif image. In some embodiments, it is appropriate to arrange the microfocusing elements and the micromotif elements on the same side of the carrier. Bilateral designs in which a micromotif element array can be viewed through two opposing microfocuser assemblies are also contemplated and discussed in more detail below in this specification.

In moiré magnification arrangements, even with incomplete and irregular coloring of the elevations, regular structures can be seen when viewed through the lens array, as shown above explained functional principle in each case many individual structures - here the elevations and depressions of the relief structure - are averaged to the visible structure. Therefore, it is also possible to provide as elevations fragmentary, raised structures that overlap only when viewed through the microlenses and form the desired motif. By mixing colorless areas, the achievable maximum contrast is then somewhat reduced.

This principle can also be used to form differently colored microstructure elements. If, for example, a first image component with more intense colors appears as a second image component, then the relief structure can be formed, for example, such that each elevation carries the first pictorial component, but only every second elevation carries the second pictorial component. When viewed, the second image component then appears with a lower color saturation than the first image component. In the same way can be produced by different colors of the same image component for the viewer mixed colors.

The carrier with the applied microstructure, in addition to the elements already mentioned also with one or more functional layers for use as a security element for security papers, documents of value and the like may be equipped, in particular layers with visually and / or machine-detectable security features, protective or cover layers, adhesive layers , Heat sealing equipment and the like come into consideration.

To protect against counterfeiting and / or to facilitate further processing, the microstructure applied to the carrier is advantageously provided with a transparent topcoat.

According to the invention, the relief structure of the carrier is formed by a structured, in particular self-adhesive, resist coating, the areas of which, after structuring, are high or low, forming the elevations and depressions of the relief structure. Because of the achievable high resolution, the relief structure is alternatively formed by an embossed structure with elevations and depressions.

The relief structures of the support are preferably produced by embossing into thermoplastic and / or radiation-curing lacquers.

The invention also includes an article, in particular a data carrier or a security element, with a microstructure produced in the manner described. The microstructure is formed by microstructure elements with a line thickness between about 1 μm and about 10 μm and / or preferably with a texture depth between about 0.5 μm and about 20 μm, preferably between about 1 μm and about 10 μm. Of course, the microstructures can also contain areal areas and can have both positive elements and negative elements. The elevations and depressions may also at least partially form a coherent network.

The support of the microstructure may in particular comprise a transparent plastic film or else a paper layer. Advantageously, the support has a thickness of between about 3 μm and about 50 μm, preferably between about 5 μm and about 25 μm.

According to a particularly preferred development, the article contains a micro-optical moiré magnification arrangement of the type already described and with the dimensions already indicated.

In a preferred embodiment, the article represents a security element, in particular a security thread, a label or a transfer element for application to a data carrier. The security element can be equipped for this purpose, for example, heat sealable. The total thickness of the security element is suitably between about 20 microns and about 60 microns, preferably between about 30 microns and about 50 microns.

It is likewise preferred if the article is a data carrier, in particular a banknote, a document of value, a passport, a passport card or a document.

The article with the applied microstructure can moreover be equipped with one or more functional layers, in particular with layers with visually and / or machine-detectable security features. In this case, for example, all-surface or partial reflective, high-refractive or color-shifting layers in question, or even polarizing or phase-shifting layers, opaque or transparent conductive layers, soft or hard magnetic layers or fluorescent or phosphorescent layers.

The invention further comprises a microstructure which can be produced in the described manner and which has a relief structure with elevations and depressions, the shape and arrangement of which form the structural elements of the microstructure, and in which a printing material selectively uses a printing tool either transferred only to the elevations or only in the depressions of the relief structure.

The invention further comprises a method for producing a high-resolution printing layer on a target substrate, in which a microstructure is first produced by a method of the type described above, in which the imprint material is selectively transferred essentially only to the elevations of the relief structure. The microstructure thus produced is then brought into contact with the desired target substrate and the imprint material present on the elevations of the relief structure is transferred to the target substrate.

Further embodiments and advantages of the invention are explained below with reference to the figures. For better clarity, a scale and proportioned representation is omitted in the figures.

Fig. 1

eine schematische Darstellung einer Banknote mit einem eingebetteten Sicherheitsfaden und einem aufgeklebten Transferelement,

Fig. 2

in (a) und (b) schematische Darstellungen zur Erläuterung des Prinzips der Erfindung,

Fig. 3

eine Kombination der Erfindungsvarianten der Figuren 2(a) und (b),

Fig. 4

schematisch den Schichtaufbau einer Moire-Vergrößerungsanordnung im Querschnitt,

Fig. 5

ein Ausführungsbeispiel, bei dem eine erfindungsgemäße mikroskopische Strukturierung mit einer herkömmlichen makroskopischen Strukturierung kombiniert ist,

Fig. 6

in (a) bis (c) Zwischenschritte bei der Herstellung einer farbigen Moire-Vergrößerungsanordnung, die gepassert mit einer Metallisierung kombiniert ist,

Fig. 7

in (a) bis (d) Zwischenschritte bei der Herstellung einer Moiré-Vergrößerungsanordnung, die mit einem Hologramm kombiniert ist,

Fig. 8

eine zweifarbige Mikrostruktur nach einem weiteren Ausführungsbeispiel der Erfindung,

Fig. 9

in (a) bis (e) Zwischenschritte bei der Herstellung eines Sicherheitselements mit zwei verschiedenen, von gegenüberliegenden Seiten sichtbaren Hologrammen, die ein gemeinsames und damit perfekt gepassertes Negativmuster aufweisen,

Fig. 10

eine Moire-Vergrößerungsanordnung, auf deren Linsenarray mit einem erfindungsgemäßen Verfahren eine Klebeschicht übertragen ist,

Fig. 11-13

jeweils einen in Papier eingebetteten Fenstersicherheitsfaden nach einem Ausführungsbeispiel der Erfindung,

Fig. 14

in (a) und (b) Zwischenschritte bei der Herstellung einer weiteren erfindungsgemäßen Mikrostruktur,

Fig. 15

in (a) und (b) Zwischenschritte bei der Herstellung einer erfindungsgemäßen Mikrostruktur mit Rückseiteneffekten,

Fig. 16

in (a) und (b) Zwischenschritte bei der Herstellung einer erfindungsgemäßen Mikrostruktur mit zwei verschiedenen, von gegenüberliegenden Seiten sichtbaren Hologrammen,

Fig. 17

in (a) bis (c) Zwischenschritte bei der Herstellung einer erfindungsgemäßen mikrooptischen Vergrößerungsanordnung mit farbigen metallischen Mikrostrukturen,

Fig. 18

in (a) bis (c) Zwischenschritte bei der Herstellung weiterer erfindungsgemäßer metallisierter Mikrostrukturen, und

Fig. 19

in (a) und (b) den Einsatz einer erfindungsgemäßen Mikrostruktur zum Erzeugen einer hochaufgelösten Druckschicht auf einem Zielsubstrat.

Show it:

Fig. 1

a schematic representation of a banknote with an embedded security thread and a glued transfer element,

Fig. 2

in (a) and (b) are schematic illustrations for explaining the principle of the invention,

Fig. 3

a combination of the invention variants of FIGS. 2 (a) and (b) .

Fig. 4

schematically the layer structure of a Moire magnification arrangement in cross-section,

Fig. 5

an embodiment in which a microscopic structuring according to the invention is combined with a conventional macroscopic structuring,

Fig. 6

in (a) to (c) intermediate steps in the production of a colored moiré magnification arrangement, which is combined with a metallization matched,

Fig. 7

in (a) to (d) intermediate steps in the production of a moiré magnification arrangement combined with a hologram,

Fig. 8

a two-color microstructure according to a further embodiment of the invention,

Fig. 9

in (a) to (e) intermediate steps in the production of a security element having two different holograms visible from opposite sides and having a common and thus perfectly matched negative pattern,

Fig. 10

a moiré magnification arrangement, on the lens array of which an adhesive layer is transferred by a method according to the invention,

Fig. 11-13

each one embedded in paper window security thread according to an embodiment of the invention,

Fig. 14

in (a) and (b) intermediate steps in the production of a further microstructure according to the invention,

Fig. 15

in (a) and (b) intermediate steps in the production of a microstructure according to the invention with backside effects,

Fig. 16

in (a) and (b) intermediate steps in the production of a microstructure according to the invention with two different holograms visible from opposite sides,

Fig. 17

in (a) to (c) intermediate steps in the production of a microoptical magnification arrangement according to the invention with colored metallic microstructures,

Fig. 18

in (a) to (c) intermediate steps in the production of further metallized microstructures according to the invention, and

Fig. 19

in (a) and (b) the use of a microstructure according to the invention for producing a high-resolution printing layer on a target substrate.

The invention will now be explained using the example of security elements for banknotes. Fig. 1 shows a schematic representation of a banknote 10, which is provided with two security elements 12 and 16 according to embodiments of the invention. In this case, the first security element represents a security thread 12 which emerges in certain window areas 14 on the surface of the banknote 10, while it is embedded in the intervening areas in the interior of the banknote 10. The second security element 16 is formed by a glued transfer element of any shape educated. In other embodiments, the security element 16 may also be designed in the form of a cover film, which is arranged in or above a window area or a through opening of the banknote.

First, the principle of the invention with reference to the schematic representations of Fig. 2 explained. Subsequently, with reference to the other figures, some specific embodiments of security elements according to the invention will be described by way of example.

That in the FIGS. 2 (a) and (b) shown security element 20 contains as a carrier film 22, for example, a transparent PET film. On the upper side of the carrier film 22, a UV-curing embossing lacquer layer 24 is applied, into which an embossed structure with elevations 26 and depressions 28 in the form of a desired microstructure is embossed.

The nature of the microstructure is only of secondary importance to the present invention. For example, the microstructures contemplated may be micro-optical magnification arrangements, such as moiré magnification arrangements, moiré-type micro-optic magnification arrangements, or modulo magnification arrangements, or other micro-optic structures such as blazed grating structures, DOE (diffractive optical element) structures computer-generated holograms (CGH) or other hologram-like diffraction patterns, microlens structures, or fresnel lens-like structures. Particular advantages of the invention in high-resolution microstructures, the microstructure elements are formed with a line thickness between about 1 micron and about 10 microns and with a structural depth between about 0.5 microns and about 20 microns. The elevations and depressions of the embossed structure in the present invention in each case form the microstructure elements the microstructure, so that the dimensions of the elevations or depressions correspond to those of the microstructure elements.

In order to apply printing ink in a first variant of the invention substantially only to the elevations 26 of the embossed structure, the embossed pattern is printed, for example, in offset printing at low pressure with a high-viscosity printing ink 30, as in Fig. 2 (a) shown. In particular, radiation-curable or thermosetting offset printing inks with a dynamic viscosity between 800 mPa * s and 150 Pa * s at room temperature are considered. A thin, not fast drying paint can be achieved, for example, by rubbing the paint through a system consisting of several rotating rollers, dispensing with volatile solvents.

The ink 30 is applied in a layer thickness d, which is significantly smaller than the depth t of the embossed structures. The hardness of the printing tool and optionally a counter roll and the pressure when transferring the ink are each selected according to the desired size and depth of the transfer areas 32. On the one hand, the pressure during transfer is chosen to be so low on the one hand that the printing ink 30 is not squeezed, but on the other hand high enough that ink is transferred in the area of the elevations 26. By setting a higher pressure, the transfer area 32 can also be increased. If, for example, there are more than two height levels in the case of an embossed structure, not only is the top height level in contact with the ink 30 experienced during the printing process, then different color quantities can be transferred depending on the level. The relationship between pressure and size of the transmission range is not linear; from a very high level, color can even be squeezed out by pressure.

In a particularly advantageous variant of the method, the printing ink is transferred to the embossing structure virtually without contact pressure, a defined distance between the application unit and the surface of the embossing structure being filled by the printing ink on or on the application unit.

In the described approach and sufficiently low pressure, no contact between the highly viscous ink 30 and the recesses 28 of the embossed structure, so that selectively substantially only the elevations 26 of the microstructure are provided with color and a gravure typical, full-tone Tonungsfilm is avoided. As explained in more detail below, with the described method not only printing inks but also other imprint materials, such as an adhesive or a resist coating can advantageously be selectively transferred to the elevations 26 of an embossed structure.

Embossed structures can be readily prepared by methods known per se with the highest accuracy of the dimensions of their elevations and depressions. Due to the selective transfer of the highly viscous printing ink only on the elevations of the embossed structures, the high resolution of the embossed structure is transferred to the printed image, so that a printed image can be produced with an extraordinarily high resolution.

Regarding Fig. 2 (b) According to a second variant of the invention, printing ink can also be selectively transferred essentially only into the depressions 28 of the embossed structure. For this purpose, for example, in flexographic printing or intaglio printing, such a low-viscosity printing ink 34 is applied to the embossed structure that the printing ink 34 flows into the depressions 28 and leaves the elevations 26 uncovered. In addition to the choice of the Viscosity and the surface tension of the ink are matched to the surface energy of the embossed structure.

Suitable printing inks for this variant of the invention are, in particular, dye solutions, pigment dispersions or inks having a viscosity of between 3 mPa * s and 1500 mPa * s at room temperature. In this variant of the invention, in addition to printing inks, other low-viscosity printing materials, such as low-viscosity adhesives or liquid-crystal solutions, can also be transferred selectively into the depressions 28.

The transfer of the ink into the recesses 28 can also be done in two steps. In this case, first a low viscosity ink is transferred with a low binder content, which selectively flows into the recesses 28 of the embossed structure. Subsequently, a solution with a high binder content is transferred, which fixes the colorants of the printing ink in the recesses 28 of the embossed structure and subsequently embedded in a binder matrix.

The selective transfer of the imprint materials on the elevations or into the recesses according to the first or second variant of the invention can be further enhanced by targeted structuring of the elevations or depressions. For example, the elevations 26 in the variant of Fig. 2 (a) be formed with a sharply defined, upstanding edge region which limits the raised microstructure elements. The imprint material transferred to the elevations 26 is thus limited even more to the region of the elevations 26. The upstanding edge region may have, for example, a height of about 1 .mu.m to 2 .mu.m. Optionally, the requirements for the viscosity of the imprint material can be reduced by this measure.

In the variant of Fig. 2 (b) For example, the bumps 26 may additionally be provided with a lotus structure that creates a low wettable bump surface. The lotus structures reduce the contact area between the protrusions and the transferred imprint material, so that it can not adhere to the surface of the elevations 26 practically and flows more easily into the recesses 28. Optionally, the requirements for the viscosity of the imprint material can be reduced by this measure.

If a low-viscosity solution of nematic liquid crystals is selected as the imprint material, the recesses 28 can be provided with alignment structures for aligning liquid-crystalline material. After removing the solvent, the aligned nematic liquid crystal material is crosslinked and fixed. The resulting birefringent structures may be viewed in front of a suitable reflective background by means of a polarizer, for example the lens array of a micro-optical magnification assembly described below. By different alignment directions of the alignment structures, the illustrated motif can be further structured.

In order to allow a particularly uniform flow of color into the recesses 28, it is also advisable not to let the elevations 26 grow out of the ground vertically, but to pass the recesses 28 with rounded transitions in the elevations 26, as in Fig. 2 shown. This will in particular avoid that ink 34 accumulates at the transitions between elevations and depressions. Alternatively, before transferring the desired printing ink, a small amount of low-viscosity clearcoat can be transferred first, which fills up such transitions.

The variants of the invention FIGS. 2 (a) and (b) can also be combined with each other, as in Fig. 3 shown. In the case of the security element shown schematically there, in a first step, a first highly viscous printing ink 30 was selectively applied substantially only to the elevations 26 of the embossed structure. In a second step, a second low viscosity ink 34 was then selectively transferred substantially only to the recesses 28 of the embossing pattern. How out Fig. 3 to recognize, the microstructure is not flattened or weakened by the coating with the first ink 30, so that the selective transfer of the second ink 34 can be carried out as described above.

With proper matching of the printing inks 30, 34, the first printing step can even improve the suitability of the microstructure for the transfer of the second printing ink 34, for example by applying a printing ink 30 as the first printing ink having ink-repelling properties for the second printing ink 34. With suitable process control, the order of the printing steps can in principle be reversed and first the low-viscosity printing ink in the wells and then the high-viscosity printing ink are transferred to the surveys.

Overall, the design of the Fig. 3 both as viewed 36 from the top and when viewed 38 from the bottom with microstructures of a first color (the color of the first ink 30) against the background of a second color (the color of the second ink 34).

Since the invention is explained below using moiré magnification arrangements having microstructures of a plurality of micromotif elements and microlenses, reference will be made to FIGS Fig. 4 First, the operation of such Moire magnification arrangements briefly described. The explanation by simple Moire magnification arrangements is not intended to be limiting to this type of micro-optical magnification arrangements. On the contrary, it is to be understood that the invention is also advantageous for other micro-optical magnification arrangements, in particular for the general modulo magnification arrangements as described in the applications PCT / EP2008 / 005171 and PCT / EP2008 / 005172 are described, can be used.

Fig. 4 schematically shows the layer structure of a Moire magnification arrangement 40 in cross section, wherein only the parts of the layer structure required for the explanation of the principle of operation are shown. The moire magnification arrangement 40 includes a carrier 42 in the form of a transparent plastic film, in the exemplary embodiment of an approximately 20 micron thick polyethylene terephthalate (PET) film. The upper side of the carrier foil 42 is provided with a grid-like arrangement of microlenses 44 which form on the surface of the carrier foil a two-dimensional Bravais grid with a preselected symmetry. The Bravais lattice may, for example, have a hexagonal lattice symmetry, but because of the higher security against forgery, preferred are lower symmetries and thus more general shapes, in particular the symmetry of a parallelogram lattice.

The spacing of adjacent microlenses 44 is preferably chosen as small as possible in order to ensure the highest possible area coverage and thus a high-contrast representation. The spherically or aspherically configured microlenses 44 preferably have a diameter between 3 .mu.m and 50 .mu.m and in particular a diameter between only 10 .mu.m and 35 .mu.m and are therefore not visible to the naked eye.

On the underside of the carrier film 42, a motif layer 46 is arranged, which also contains a grid-like arrangement of identical micromotif elements 48. The arrangement of the micromotif elements 48 forms a two-dimensional Bravais lattice with a preselected symmetry, again assuming a parallelogram lattice for illustration. As in Fig. 4 indicated by the offset of the micromotif elements 48 relative to the microlenses 44, the Bravais lattice of the micromotif elements 48 differs slightly in its symmetry and / or in the size of its lattice parameters from the Bravais lattice of the microlenses 44 to produce a desired moire magnification effect , The grating period and the diameter of the micromotif elements 48 are of the same order of magnitude as those of the microlenses 44, that is to say preferably in the range of 3 μm to 50 μm and in particular in the range of 10 μm to 35 μm, so that the micromotif elements 48 themselves are visible to the naked eye are not recognizable.

The optical thickness of the carrier film 42 and the focal length of the microlenses 44 are matched to one another such that the micromotif elements 48 are located approximately at the distance of the lens focal length. The carrier film 40 thus forms an optical spacer layer which ensures a desired constant spacing of the microlenses 44 and the micromotif elements 48. Due to the slightly differing lattice parameters, the observer sees a slightly different subarea of the micromotif elements 48 when viewed from above through the microlenses 44, so that the multiplicity of microlenses 44 overall produces an enlarged image of the micromotif elements 48. The resulting moire magnification depends on the relative difference of the lattice parameters of the Bravais lattice used. If, for example, the grating periods of two hexagonal gratings differ by 1%, the result is a 100-fold moire magnification.

For a more detailed description of the operation and advantageous arrangements of the micromotif elements and the microlenses is to the publications DE 10 2005 062 132 A1 and WO 2007/076952 A2 directed.

In order to be able to produce such a moiré magnification arrangement with differently colored micromotif elements in the required fineness, the method according to the invention can be combined with a conventional macroscopic structuring, for example by a printing form. Regarding Fig. 5 In this case, an embossed structure 50 applied to a carrier foil dictates, by virtue of its microstructuring, which of the micrometer-sized subregions 52 are to be provided with ink and thus form the micromotif elements of a moiré magnification arrangement, and which subareas 54 are not to be printed.

According to in connection with Fig. 2 (a) described method, the embossing structure 50 to elevations 56, which are formed in the shape and arrangement of the desired micromotif elements. Embossed structures can also be produced without difficulty in the high resolution required for the micromotif elements. By transferring a high-viscosity printing ink 60 to the embossing structure 50, substantially only the elevations 56, but not the depressions 58, are selectively colored, so that the high resolution of the embossing is transferred into a high-resolution print image.

This high-resolution structure 52, 54 through the embossed structure 50 can now be combined with a low-resolution structure 62, 64, 66, which is given for example by a printing forme, to a to produce multicolor moire magnification arrangement. For this purpose, highly viscous printing inks 60 of different colors are transferred to the elevations 56 in comparison with the micromotiv subregions 52, 54, substantially more extensive, macroscopic regions 62, 64, 66. With appropriate design, the moire magnified motif shown can then move from one color area to the next color area when the finished moire magnification arrangement is tilted.

Since an exact juxtaposition of colors is often difficult, designs are advantageously used in which between two desired color areas 62, 66, a mixed color area 64 is provided. For example, an intermediate region 64 printed with green printing ink can be provided between a motif region 62 printed with blue printing ink and a motif region 66 printed with yellow printing ink. Such a procedure offers in particular at low opaque colors. For strongly opaque colors, the smallest color range can be printed first, then the next larger one, until finally a full surface is applied. The order of the print layers naturally reverses if the lens array of the moire magnification arrangement does not, as in FIG Fig. 4 shown to lie on the opposite side of the carrier, but what is also possible, is applied to the pressure side.

When printing a plurality of at least partially opaque color layers results in a multi-color moire magnification arrangement, which gives a different color impression when viewed from above or from below. This different color impression can be made more visible by applying lens arrays on both sides of the arrangement.

Instead of two colors, a combination of a color and a metal layer can also be used. Also, a combination of two colors and an intermediate metal layer comes into consideration, as shown in more detail below. The metal layer can also be produced by oblique vapor deposition of the relief structure, so that a demetallization for exposing the depressions can be dispensed with if the vapor deposition angle is suitably matched. If, for example, no suitable offset ink with resist properties is available, the desired effect can also be obtained by suitable oblique evaporation of the relief structure without demetallization.

In the exemplary embodiments described below, the elevations and depressions of the microstructures are always shown as rectangular structures for the sake of clarity. However, it is understood that the elevations and depressions can always be rounded, provided with continuous transitions and / or with additional structures, as explained above. Also, only the embossed structure and the layers necessary for explanation are shown and other elements of the structure, such as carrier films, adhesive and protective layers or the moire magnification arrangement lens arrays, are omitted. Also, all survey / recess structures can be filled, for example, with a clear coat to protect the printed elevations and depressions against unwanted filling with dirt and against manipulation or impressions.

Fig. 6 shows an embodiment in which a colored microstructure, for example a colored moiré magnification arrangement, matched with a metallization is combined. In order to achieve this registration, an embossed structure 70 with elevations 72 and depressions 74 is first produced, which form the structural elements of the desired microstructure. The embossed structure 70 is then provided over the entire surface with a metallization 76, as in Fig. 6 (a) shown. Then, a colored, highly viscous resist coating 78 is applied to the metallization 76, which in the manner described above selectively covers substantially only the elevations 72 of the embossed structure 70, as in FIG Fig. 6 (b) shown. Subsequently, the embossed, metallized and provided with resist coating structure is demetallized in a known per se, for example by means of an alkali. As in Fig. 6 (c) In this case, the metallization 76 is retained on the elevations 72 protected by the resist 78 while the metallization 76 in the depressions 74 is removed.

This creates a double-viewable microstructure with a perfectly matched visual appearance. Viewing 80 from above, the microstructure appears with the color impression of the resist 78, when viewed 82 from below with the metallic luster of the metal layer 76. If the elevations and depressions form the micromotif elements of a moiré magnification arrangement, a lens array can be formed on both sides of the microstructure be applied, by the colored (viewing direction 80) and metallic (viewing direction 82) micromotif moire-magnified visible. The demetallized areas of the recesses 74 represent congruent recesses in both appearances, which may be in the form of a negative writing or in the form of any other patterns, characters or codes.

If desired, the resist 78 may also be removed after demetallization. The microstructure then appears from both sides with the metallic impression of the metallization 76 and with perfectly matched recesses 74. Are in this or other embodiments larger contiguous Demetallisierungsflächen provided in the microstructure, it is preferably applied to the embossed structure before the metallization, a soluble wash color in the form of the desired Demetallisierungsbereichs, and washed off the washing paint before transferring the resist together with the metallization by a solvent.

By suitable design of the embossed structure, the microstructure formed by the elevations and depressions can be combined with a further microoptical structure. For example, a moiré magnification arrangement can be combined with a hologram, as will now be described with reference to the embodiment of FIG Fig. 7 explained.

Fig. 7 shows an embossed structure 90 with protrusions 92 and recesses 94, which form in their shape and arrangement of the micromotif elements of a moiré magnification arrangement. In addition, the surfaces of the protrusions 92 are provided with diffractive microrelief structures 96 carrying a desired holographic information. By contrast, the depressions 94 of the embossed structure do not contain any optically relevant information.

The embossed structure 90 is first provided over the entire surface with a metallization 98, as in Fig. 7 (a) shown. Then, on the metallization 98, a highly viscous resist 100 is applied which, in the manner described, selectively covers substantially only the elevations 92 of the embossment pattern 90, as in FIG Fig. 7 (b) shown. Subsequently, the embossed, metallized and provided with resist coating structure is demetallisiert and the resist 100 is removed. This leaves, as in Fig. 7 (c) 4, the metallization 98 is obtained on the elevations 92 provided with the microrelief structures 96, while the depressions 94 are demetallized.

On the one hand, this procedure results in a moiré magnification arrangement with a metallic appearance, in which micromotif elements are formed by the shape and arrangement of the recesses 92 and elevations 94. In addition, the assembly includes a hologram encoded only in the raised regions 96 of the embossment pattern 90. However, since the dimensions of the protrusions 92 and depressions 94 are below the resolution limit of the human eye, it is not apparent to the viewer that the holographic information 96 is present only on the elevations 92, so that the holographic image is perceived by the viewer as a full-surface image.

In an alternative variant of the method, a highly viscous resist 100 of a desired color is applied to the embossed structure, and after removal of the resist 100, the demetallization is dispensed with, so that the in Fig. 7 (d) produced embossed structure arises. If the resist layer 100 is designed to be opaque, a colored moire magnification arrangement can be seen from above in this embodiment when viewed 102 from above, and the hologram of the microrelief structures 96 can be seen from below when viewed 104.

If the resist layer 100 is translucent or is removed after removal of the resist, as in FIG Fig. 7 (c) , printed on the elevations 92, a translucent, highly viscous color layer, so when viewing 102 from above in addition to the colored Moire magnification arrangement and the translucent hologram of the microrelief structures 96 can be seen.

Regarding Fig. 8 For example, a unique two-color microstructure can be produced by firstly applying a first high-viscosity printing ink 110 selectively to the elevations 72 of a stamping layer 70, the printed stamping layer having a full-surface area Metallization 112 is provided, and then a colored, highly viscous resist coating 114 is selectively applied to the protrusions 72 of the metallized embossed layer. After demetallization, the results in Fig. 8 shown microstructure, which appears when viewed 116 from above with the color impression of the colored resist 114 and the 118 appears from below with the color impression of the first ink 110. The depressions 74 form congruent recesses from both viewing directions. If desired, one or both color layers 110, 114 may be translucent such that the metallization 112 remains visible through the color layers. In this case, the projections 72 may also be provided with diffractive microrelief structures, as in connection with FIG Fig. 7 to provide a combination of the bi-color microstructure with a hologram or other micro-optical structure.

With an alternative production variant, such a clearly two-color microstructure can also be produced without demetallization step. For this purpose, the printed embossing layer 70, 110 is metallized at an oblique angle with metal, so that the metallization 112 is present only on the elevations 72 and one flank side of the elevations 72. The depressions 74 are shaded by the elevations 72 at a suitably selected evaporation angle, so that no metal deposits there. Subsequently, a further colored lacquer 114 is selectively applied to the elevations 72, so that the desired color impression is produced without demetallization.

Fig. 9 shows as a further embodiment of the invention, a security element 120 with two different, visible from opposite sides Holograms that have a common, perfectly matched negative pattern, such as negative writing.

To produce such a security element 120, an embossed structure with elevations 122 and depressions 124 in the form of a desired microstructure is first of all produced. The surfaces of the elevations 122 are provided with diffractive microrelief structures 126, which carry the holographic information of the second, later visible from below 140 hologram. The depressions 124 do not contain any optically relevant information, but rather represent the later negative writing areas.

The embossed structure is then provided over its entire surface with a metallization 128, as in FIG Fig. 9 (a) shown. On the metallization 128, a highly viscous thermoplastic resist coating 130 is applied, which selectively covers essentially only the elevations 122 of the embossed structure in the described manner. The thermoplastic resist 130 is provided with an embossing in the form of diffractive microrelief structures 132, which carry the holographic information of the first hologram, visible later from above 138, as in FIG Fig. 9 (b) shown.

The structure thus obtained is again provided with a full-surface metallization 134, as in Fig. 9 (c) and the protrusions 122 of the embossment pattern are again coated with a high viscosity resist 136, as in FIG Fig. 9 (d) shown. By a demetallization step, both metallizations 128, 134 are then removed in the region of the depressions 124. Subsequently, the resist 136 is removed from the bumps 122 to the in Fig. 9 (e) To obtain shown double-sided hologram structure.

Viewing 138 of the top of the microstructure, the first hologram formed by the diffractive microreliefs 132 is visible, as viewed 140 from below, the second hologram formed by the diffractive microreliefs 126. Both holograms contain a common, congruent negative information formed by the recesses 124. If desired, another high viscosity ink may be transferred to the bumps 122 to make the first hologram appear colored from the top when viewed 138.

Instead of embossing a thermoplastic resist 130, as in Fig. 9 (b) described, after applying a resist 130 and a first demetallization can be carried out, which removes the metallization 128 in the region of the recesses 124. Then, a thin, full-surface embossing lacquer layer is applied, which follows the arrangement of the elevations 122 and recesses 124. This embossing lacquer layer is then provided with diffractive microrelief structures 132, which carry the holographic information of the first, later visible from above hologram. This is followed by a renewed full-surface metallization 134, application of a high-viscosity resist coating 136 to the elevations 122 and renewed demetallization. Also in this procedure, a security element is created, which has two holograms visible from opposite sides with congruent negative information in the region of the recesses 134, although with respect to the method of Fig. 9 an additional demetallization step is required.

Instead of a printing ink or a resist varnish, other imprint materials, for example an adhesive, can also be selectively transferred to the elevations or into the depressions of a microstructure without leveling the predetermined microstructures.

Regarding Fig. 10 For example, the microlenses 44 of a lens array for a moiré magnification arrangement 40 can be provided with an adhesive layer 150 in the manner described. The heat-sealing lacquer to be transferred must be adjusted to high viscosity and block-free at room temperature. The heat sealing lacquer may be, for example, in addition to conventional aqueous-based systems, for example, a water-activatable adhesive system which is activated by the moisture in the paper machine.

By this measure, for example, embedded in a paper substrate security thread moire magnification arrangement not only on the side of the motif layer, but also on the side of the lens array via an adhesive layer to the paper are connected. In conventional designs, however, the side of the microlenses always remains open, resulting in a weaker anchorage of the security thread. It is understood that the additional adhesive layer 150 with its refractive index can already be suitably taken into account when designing the geometry and refractive index of the microlenses 44. Of course, adhesive material can also be selectively applied to the raised areas of an embossed pattern on the motif side of a moire magnification arrangement 40.

Fig. 11 illustrates another way to embed a security thread, in particular a window security thread 180, in paper 182 with a micro-optical magnification arrangement. A disadvantage of conventional security threads with micro-optical magnification arrangements is a poor embedding in the paper. For a good embedding, it is desirable to provide the security threads both on their top and bottom with an adhesive that will ensure that the security thread is well adhered to the paper. This is especially true at Window security threads of importance, since in these the paper 182 in the form of window bars 183 rests on the security thread. These window webs 183 have a length of a few millimeters up to about 20 mm.

If the top side of a security thread is not coated with adhesive, the paper web rests on the security thread without an adhesive bond. Between the top of the thread and the paper web, a gap can form in circulation which can lead to the paper web being torn or torn off and thus to highly visible and undesired changes in the embedding value document. In the case of banknotes, such non-glued-in security threads also tend to tear the paper in the area of the security thread so that the security thread actually embedded there is visible at the margin of the note.

In the previously known security threads with micro-optical magnification arrangements, the upper side of the thread can not now be coated with adhesive, since the adhesive would level the topography of the lenticular and would destroy the focusing effect of the lenses due to the similar refractive indices of adhesive and lens material.

According to the invention, however, in a micro-optical magnification arrangement 40 with microlenses 44, highly viscous adhesive 184 can be applied selectively only to the upper regions of the microlenses 44 and then a laminating film 186 can be laminated onto the microlens array 44. For embedding in paper 182, 183, both the lower side of the thread and the upper side of the thread can be provided with an adhesive layer 188, as in FIG Fig. 11 shown.

Since the adhesive 184 covers only the uppermost region of the microlenses 44, apart from the adhesive regions, a multiplicity of microcavities 185 are created between the laminating film 186 and the microlens array 44. The microcavities 185 are filled with air (n = 1) and therefore have a large refractive index difference the material of the microlenses (n ≈ 1.5), so that the focusing effect of the microlenses 44 is substantially retained despite the lamination of the film 186. In the uppermost regions of the microlenses 44, in which the laminating film 186 is connected to the lenses via the adhesive 184, the beam path through the lens is anyway substantially perpendicular when viewed, so that the optical effect of the lenses there through the adhesive 184 is practical is not affected. This applies in particular to lenses in the form of spherical caps as well as for lenticular lenses.

This in Fig. 11 The illustrated principle can be used not only in the micro-lenses micro-optical magnification arrangements, but with advantage generally in unmetallized, optically variable microstructures. While the optically variable effect of metallized microstructures is generally only slightly influenced by covering with lacquers or lamination with a foil, an optically variable effect of unmetallised microstructures is generally lost by coating with lacquer or bonding with a foil. This is mainly because the refractive indices of typical microstructure materials, such as an embossing lacquer layer, and typical adhesives are almost always close to each other. The surrounding adhesive then prevents effective light deflection through the microstructures and thus the desired refractive or optically variable effect.

Regarding Fig. 12 For example, a window security thread 190 includes a backing 192 and a non-metallized relief structure 194 that forms an optically variable microstructure. In Fig. 12 For example, the relief structure is shown in the form of a blazed grating 194, but the invention is also applicable to any other unmetallized relief structures. On the elevations of the relief structure 194, here the uppermost area of the Blazegitterelemente, a highly viscous adhesive 196 is selectively applied in the manner described above. Then, as already related to Fig. 11 a laminating film 186 laminated on the optically variable microstructure 194 and the security thread 190 securely embedded on the top and bottom adhesive layers 188 in the paper 182, 183.

Since the adhesive 196 covers only the uppermost portion of the blazed grating elements 194, a plurality of air-filled microcavities 195 are formed between the laminating film 186 and the optically variable microstructure. The blazed grating elements are therefore in an air environment with a large difference in refractive index, so that their optically variable effect is substantially retained despite the lamination of the film 186.

In a modification of the designs of FIGS. 11 and 12 the microstructure is designed specifically with regard to the subsequent lamination of a film. For this purpose, the microstructure contains, in addition to the user surveys or utility depressions which produce the desired optical effect, also support surveys without an optical effect, which merely serve for bonding to the laminating film. For illustration shows Fig. 13 a window security thread 200 with a micro-optical magnification arrangement 202, which except for the additionally provided in the plane of the lens array support embossing 204 of the micro-optical magnification arrangement 40 of Fig. 11 equivalent.

In the embossing of the microlenses 44, in addition to the optically active microlenses 44, regularly arranged support columns 204 are embossed into the embossing lacquer layer, which themselves do not have an optical effect but which project beyond the microlenses 44 so far that during the transfer of the adhesive 206 onto the embossed structure 44, 204 only the support columns 204, but not the microlenses 44 come into contact with the adhesive 206. The microlenses 44 remain therefore even after the bonding of the embossed structure 44, 204 with the laminating film 186 completely in air environment 208 and receive their optical effect undisturbed.

Of course, this variant of the invention can be used not only in micro-optical magnification arrangements, but generally in optically variable microstructures. Particularly good results are achieved with optically variable embossing structures whose optically effective embossed structure elements (user surveys) are not too high. Preferably, the user surveys are not higher than 10 μm, more preferably not higher than 5 μm.

By way of example, the embossed structure may comprise optically active elements (user elevations) as diffractive optical elements which, when irradiated with a laser beam, project a predetermined image onto a screen. The structures of the diffractive optical elements typically have lateral dimensions of 0.5 μm to 30 μm and a height of barely more than 1 μm. Without support projections according to the invention, these embossed structure elements are too thin for covering with a film because the required adhesive penetrates into the intermediate spaces of the embossed structure elements run and destroy their visual impact. In contrast, can be generated by providing additional support surveys controlled a desired air-filled distance between the user surveys and the laminating film.

The shape and area coverage of the support surveys can vary widely. The support surveys may be formed, for example in the form of columns or webs in a regular or irregular arrangement.

A further possibility to specifically form the microstructure with regard to the subsequent lamination of a film is to provide the microstructure elements in their uppermost regions with small recesses intended to receive adhesive droplets. The recesses are in particular designed so that the complete form of the microstructure elements is restored by the transfer of small adhesive droplets. For example, in the uppermost regions of the microlenses 44 of the Fig. 11 small dentures are provided, which are supplemented by the inclusion of adhesive droplets to complete lens shape.

Although not part of the present invention, it is also possible in principle, the designs of FIGS. 11 to 13 in that not the uppermost area of the relief structure is provided with adhesive, but that the laminating film is very thinly coated with adhesive and that the microstructure is coated with such a prepared laminating film. The adhesive layer must be so thin or must be so little melted or deformed that they only the top areas of the Microstructure evidenced, so that between the laminating film and the microstructure air-filled microcavities arise.

The transfer of an adhesive to the elevations of an embossed structure, for example, also allows the addition of additional holographic structures, as based on the embodiment of Fig. 14 explained. Fig. 14 shows an embossing structure 160 with elevations 162 and depressions 164, which form a desired microstructure in shape and arrangement. As in the embodiment of FIGS. 7 and 9 the surfaces of the elevations 162 are provided with diffractive microrelief structures 166 which carry a desired holographic information, while the depressions 164 contain no optically relevant information. As already described above, the protrusions 162 of the embossing structure 160 have been selectively provided with a metallization 168, as in FIG Fig. 14 (a) shown.

In order to apply additional holographic structures, a highly viscous pressure-sensitive adhesive 170 is selectively transferred to the elevations 162. The thus prepared embossed structure 160 is then brought into contact with another film 172, which carries a metallized, continuous and releasably formed hologram 174. By appropriate adjustment of temperature and pressure, the holographic structures 174 of the film 170 are selectively transferred to the adhesive-carrying protrusions 162 of the embossing structure 160. Also in this way, a security element can be created with two holograms visible from opposite sides, which have a common, perfectly matched negative pattern 164. If desired, another high viscosity ink may be transferred to the bumps 162 to make the hologram 174 appear colored when viewed from above.

Further possibilities for providing the microstructure with additional optical effects will now be described with reference to FIGS FIGS. 15 and 16 illustrated by the example of motif images of micro-optical magnification arrangements. Conventional micro-optical magnification arrangements often have the disadvantage that they are without an optical effect from the rear or that the application of, for example, a mirrored rear hologram clearly affects and disturbs the front view.

Fig. 15 (a) shows an embossing structure 212 present on a first carrier foil 210 with elevations 214 and depressions 216, which form in their shape and arrangement the motif image of a micro-optical magnification arrangement. The surface of the protuberances may be left transparent or selectively coated with a paint 218 in the manner described above. On the side of the carrier foil 210 opposite the embossing structure 212, a microlens grid (not shown) is applied in a known manner during the further course of the production process for viewing the motif image formed by the embossing structure 212.

On a second carrier foil 220, an embossing lacquer layer 222, which is poorly anchored on the foil 220, is applied, provided with a desired hologram embossing 224, metallized 226 and optionally demetallised in regions (not shown). Then, the metallized hologram foil 220-226 is provided with a thin adhesive coating 228, brought into contact with the first carrier foil 210 under pressure, and then separated again. The profile depths of the embossed structure 212 and the layer thickness of the adhesive coating 228 are matched to one another such that the contact only exists with the elevations 214 of the embossed structure 212.

When the films 210, 220 are separated, the second carrier film 220 in the raised contact regions 214 is detached from the embossing lacquer layer 222 due to the poor anchoring, while no transfer takes place in the region of the depressions 216. The hologram 224 of the second carrier foil 220 is thereby selectively transferred only to the elevations 214 of the embossing pattern 212, as in FIG Fig. 15 (b) shown.

When viewed from the rear side R of the finished security element, the metallized embossed areas complement each other to the hologram 224 generated on the second carrier film 220. Nevertheless, the security element is still highly translucent, because with the depressions 216, large portions of the first film 210 are not covered with opaque metal are coated. When viewing from the front side V of the finished security element, the moire or modulo magnification effect of the micro-optical magnification arrangement can therefore be seen undisturbed. If the microstructures are colored 218, the metallization 226 even enhances the color effect. The holographic metallized backside image is virtually undetectable when viewed from the front side V, since the backside reconstructed hologram on the front side is greatly disturbed by the lenticular not shown in the figure.

On the second carrier foil 220, instead of a metallized hologram, a removable color-shifting element can also be applied. The color-shifting element can be formed, for example, by a color-shifting thin-film element of absorber, dielectric and reflector. In order to produce an identical or different color-shift effect on both sides of the finished security element, it is also possible to use a double-sided thin-layer element with the layer sequence absorber1, dielectric1, reflector, dielectric2, absorber2.

The color-shifting element can also be formed by a pigmented tilting ink, which is detachably applied to the carrier film 220. In further design variants, the color-shifting element contains one or more liquid crystal layers. For example, a cholesteric liquid crystal layer and, moreover, an absorbent color layer can be applied detachably to the carrier film 220. In order to produce a color shift effect on both sides of the security element, a further cholesteric liquid crystal layer can be provided over the absorbing color layer.

After the contacting and detachment of the second carrier film 220, the color-tilting element also remains only in the region of the elevations 214 on the embossing structure 212 and is thereby selectively transferred thereto. The finished security element has a color shift effect from the rear, which does not disturb the visual effect visible from the front and does not severely impair the transparency of the security element. By using double-sided color-shifting elements, a color-shift effect can also be generated on the front without greatly impairing the transparency of the security element.

The designs described are particularly suitable for micro-optical magnification arrangements which are used to cover viewing areas of works documents. Micro-optical magnification arrangements show a good optical effect both in reflected light and in transmitted light and are therefore well suited for applications in value documents with see-through windows. Due to the backside effects described, these micro-optical magnification arrangements are further upgraded without disturbing the front moire or general modulo effect.

Fig. 16 illustrates another way to create a security element having two distinct, opposite-visible holograms with a common negative pattern.

Regarding Fig. 16 (a) For this purpose, an embossing lacquer layer 232 is applied to a first carrier foil 230 and provided with a first hologram embossing 234. After a full-surface metallization 236, a structured resist layer 238 is produced in a manner known per se, the recesses of which show the desired common negative pattern. After demetallization of the unprotected metal areas, this results in Fig. 16 (a) In this case, the patterned resist layer 238 represents a relief structure with elevations 240 and depressions 242 in the sense of the present invention.

Furthermore, a poorly anchored embossing lacquer layer 252 is applied to a second carrier foil 250, provided with a desired second hologram embossing 254, metallized 256 and optionally partially demetallised (not shown). The metallized second hologram foil 250 is provided with a thin adhesive coating 258, brought into contact with the first hologram foil 230 under pressure and, if appropriate, the action of temperature, and separated again. The profile depths of the resist coating layer 238 and the layer thickness of the adhesive coating 258 are matched to one another such that the contact only exists with the elevations 240 of the resist coating layer 238.

When separating the hologram films 230, 250, the second hologram foil 250 in the raised contact regions 240 is detached from the embossing lacquer layer 252 due to the poor anchoring, while no transfer takes place in the region of the depressions 242. The second hologram is thereby selectively transferred only to the bumps 240 of the resist layer 238, as in Fig. 16 (b) shown. The recesses 242 form a common, perfectly matched negative pattern for the two holograms 236 and 256 visible from opposite sides.

In order to produce micro-optical magnification arrangements with colored metallic microstructures, it is also possible to use the selective transfer of an imprint material into the depressions of an embossed structure. Regarding Fig. 17 An embossing structure 260 includes elevations 262 and depressions 264 with a shape and arrangement given by the desired motif image. The embossing structure 260 is provided over its entire surface with a metallization 266, for example of aluminum, as in FIG Fig. 17 (a) shown.

Then, in the manner described above, a colored resist 268 is selectively introduced into the recesses 264 of the embossing pattern 260, as in FIG Fig. 17 (b) shown. Subsequently, the metallized 266 and provided with resist 268 embossed structure is demetallized, for example by a caustic. As in Fig. 17 (c) As shown, the metallization 266 remains in the recesses 264 protected by the colored resist 268 while being removed from the surface of the protrusions 262.

These measures result in a micro-optical magnification arrangement, in which the colored microstructures are lined with metal. The reflecting metal leads to a significantly increased luminosity of the colored microstructures and thus improves the recognizability of the colored, moiré-enlarged target images. In addition, it results as an additional optical effect that the moiré-magnified target image for the viewer in transmitted light with colorless, black structures appears in appearance. The finished security element thus shows a striking reflected light / transmitted light contrast, in which the same target image appears once with bright colors (reflected light) and once as a high-contrast black and white image (transmitted light).

In one embodiment, such little colored resist 268 is filled in the recesses 264 that it is distributed around the bumps only in the corner and edge areas. The metallization covers the depressions 264 thus not the entire surface but only at the edges of the surveys. In the subsequent etching process not only the metallization is removed on the surveys but also in the uncovered areas in the wells. In this way you get a kind of outline metallization that surrounds the surveys.

Optionally, the background can be colored in an additional color, for example by using a colored embossing lacquer, a colored or color-printed carrier foil, colored microlenses or a further color coat applied after the etching process. Instead of in the wells, the colored resist can also be transferred selectively only to the elevations of the embossed structure, as already in connection with Fig. 6 explained.

Regarding Fig. 18 For example, metallized microstructures can also be created by using an adhesive lacquer transferred into the wells. Fig. 18 (a) shows an embossed structure 270 with elevations 272 and recesses 274 with a given by the desired micro-optical motif image shape and arrangement. The embossing lacquer 270 may be colored or colorless. Then, in the manner described above, a colored or colorless adhesive lacquer 276 is selectively introduced into the recesses 274 of the embossing pattern 270.

Like also in Fig. 18 (a) 1, a metal layer 282 is prepared on a further carrier film 280 over the whole area or regions, the adhesion of which to the carrier film 280 being weaker than the adhesion to the adhesive coating 276 of the embossed structure 270. This can be ensured, for example, by matching the materials of the metal layer 282 and the carrier film 280, by pretreating the carrier film 280 or by using special release layers between metal layer 282 and carrier film 280.

The carrier film 280 is then brought into contact with the filled embossed structure 270 without wrinkles under pressure and, if appropriate, temperature, and then separated again. Since the adhesion between the metal layer 282 and the adhesive varnish 276 exceeds the adhesion between the metal layer 282 and the carrier film 280, the metal layer in the filled indentation regions 274 is selectively transferred to the embossed structure 270, as in FIG Fig. 18 (b) shown. In the raised areas 272 of the embossed structure 270, no transmission takes place. In this way, metallized microimages or, if the adhesive coating 276 is colored, metallized, colored microimages are produced on embossed structure 270.

In an alternative process management, which in Fig. 18 (c) is illustrated, the embossed structure after the transfer of the colored or colorless adhesive lacquer 276 is first evaporated over the entire surface with a metal layer 282. In addition, an adhesive layer 292 is applied to a carrier film 290 over the whole area or regions, the adhesive effect of which is lower than the adhesive effect of the coating 276 introduced into the recesses 274. This support film 290 is then brought wrinkle-free under pressure and optionally temperature action with the filled and metallized embossed structure 270 in contact and then separated again. At the given relative adhesive strengths, the metal layer 282 remains in the filled recessed areas 274 on the imprinting structure 270, while in the raised areas 272 it is peeled off by the adhesive layer 292. As a result, the in Fig. 18 (b) shown design.

In further variants, the in Fig. 18 (a) After transfer of the adhesive varnish 276, the embossed structure 270 shown may be dusted with effect pigments, metal pigments or other optically active particles, the particles remaining adhering only in the regions 274 of the adhesive varnish 276. Alternatively, it is also possible to apply a color with particles which, after drying the paint, are present without stopping in the binder matrix. Of the non-adhesive regions 272, the particles are washed away or blown off in a further step.

In an alternative embodiment to the designs of Fig. 18 For example, the adhesive lacquer 276 may also be selectively transferred to the elevations of the embossed structure instead of into the depressions. Analogous to the procedure in the designs of FIGS. 18 (a) and 18 (c) is selectively transferred metal only on the surveys.

Fig. 19 shows the use of a microstructure according to the invention for generating a high-resolution print layer on a target substrate 310. As in Fig. 19 (a) For this purpose, a microstructure 300 having elevations 302 and depressions 304 in which a desired imprint material 306 is selectively transferred substantially only to the elevations 302 of the relief structure is initially produced in the manner described above. Because of the high achievable resolution, the protrusions 302 and depressions 304 are preferably generated by an embossing process. The imprint material 306 may in particular be a printing ink.

Then, the microstructure 300 is brought into contact with the target substrate 310, optionally under pressure and / or temperature. The imprint material 306 present on the elevations 302 of the relief structure is thereby transferred to the target substrate 310 with the high resolution predetermined by the microstructure 300, as in FIG Fig. 19 (b) shown. The target substrate 310 may be appropriately pretreated for this purpose.

Claims (31)

1. A method for producing a micropattern on a substrate, in which

   - a substrate is provided with a relief pattern that exhibits elevations and depressions and in which the elevations and/or depressions are arranged in the form of a desired micropattern, wherin the substrate is provided with an embossing pattern, having elevations and depressions, that forms the relief pattern, or to the substrate is applied a resist coating pattern, having elevations and depressions, that forms the relief pattern, wherein the elevations and depressions of the micropattern, micropattern elements having a line width between 1 µm and 10 µm are formed, and

   - with a printing tool, an imprint material is transferred to the relief pattern, the viscosity of the imprint material being chosen such that the imprint material is selectively transferred either substantially only onto the elevations or substantially only into the depressions of the relief pattern.
2. The method according to claim 1, characterized in that, with the printing tool, a high-viscosity imprint material is selectively transferred substantially only onto the elevations of the relief pattern.
3. The method according to claim 2, characterized in that the high-viscosity imprint material is transferred in a layer thickness that is smaller than the pattern depth of the relief patterns, especially that the layer thickness of the imprint material measures less than 50%, preferably less than 30%, particularly preferably less than 15% of the pattern depth of the relief patterns.
4. The method according to at least one of claims 2 to 3, characterized in that a desired size and/or depth of transfer regions in which the imprint material is to be transferred onto the elevations of the relief pattern is specified, and in that the hardness of the printing tool and the pressure when transferring the imprint material are chosen in accordance with the desired size and/or depth of the transfer regions, and/ or that the pressure when transferring the imprint material is chosen to be so low that the imprint material is not crushed, and/ or, that the imprint material is transferred to the relief pattern substantially without pressure, a predetermined spacing between the printing unit and the relief pattern being filled by the imprint material, and/or that an imprint material having a viscosity between 10 mPa*s and 200 Pa*s, preferably between 800 mPa*s and 150 Pa*s at room temperature is chosen, and/ or that the imprint material is transferred in the offset or flexographic printing method.
5. The method according to at least one of claims 2 to 4, characterized in that a printing ink, especially an offset printing ink, is chosen as the imprint material, and/or that a radiation-curing, heat-curing or oxidatively drying printing ink is chosen as the imprint material.
6. The method according to at least one of claims 2 to 4, characterized in that an adhesive, especially a high-viscosity heat seal coating and/or a water-activatable adhesive system, is chosen as the imprint material,
7. The method according to claim 6, characterized in that,
   after the adhesive is transferred, the relief pattern is brought into contact with a transfer medium and, in doing so, a transfer material is transferred from the transfer medium to the relief pattern elevations that are provided with adhesive, especially that an ink, a colored foil, an effect coating, effect pigments, colored pigments, black pigments, white pigments, dyes, effect layers, a metalization or sub-regions of a hologram or of a hologram-like diffraction pattern or of an optically effective micropattern are chosen as the transfer material,
   or that after the adhesive is transferred, the relief pattern is dusted with a transfer material, especially that following the dusting, an excess of the transfer material is removed, especially by a non-contact method,
   or that after the adhesive is transferred, a laminating foil is laminated onto the relief pattern, espcially that the layer sequence having substrate, micropattern and laminating foil is embedded as a security element in a security paper, value document or the like, the substrate and preferably also the laminating foil being provided with an adhesive layer.
8. The method according to at least one of claims 2 to 4, characterized in that a transfer material provided with an adhesive is transferred onto the elevations of the relief pattern as the imprint material, especially that an ink, a colored foil, an effect coating, effect pigments, colored pigments, black pigments, white pigments, dyes, effect layers, a metalization, a sub-region of a hologram or of a hologram-like diffraction pattern or of an optically effective micropattern, or a color-shifting element, especially a color-shifting thin-film element or an element including at least one liquid crystal layer is chosen as the transfer material.
9. The method according to at least one of claims 2 to 8, characterized in that an effect-pigmented imprint material that exhibits preferably luminescent pigments, thermochromic pigments, metal pigments and/or pearlescent pigments is chosen as the imprint material.
10. The method according to at least one of claims 2 to 9, characterized in that different high-viscosity imprint materials are transferred, especially imprint materials of different colors or provided with different effect pigments.
11. The method according to at least one of claims 2 to 10, characterized in that, before the desired imprint material is transferred, a high-viscosity lacquer layer is transferred to adjust for sloping edges of the elevations of the relief pattern, and/or that the elevations of the relief pattern are developed having a sharply delimited, high-standing edge region, and/or that the elevations of the relief pattern are provided with a microrelief pattern, especially with a diffractive microrelief pattern.
12. The method according to at least one of claims 2 to 11, characterized in that a high-viscosity resist coating, especially a colored, high-viscosity resist coating, is chosen as the imprint material.
13. The method according to claim 12, characterized in that the relief pattern is metalized before the high-viscosity resist coating is transferred.
14. The method according to claim 13, characterized in that after the high-viscosity resist coating is transferred, the metalized relief pattern is demetalized in regions that are not protected by resist coating, especially that.

    - after the demetalization step, the relief pattern is provided with an embossing coating layer,

    - a microrelief pattern, especially a diffractive microrelief pattern, is embossed in the embossing coating layer,

    - the relief pattern is metalized anew,

    - high-viscosity resist coating, especially a colored, high-viscosity resist coating, is transferred anew, and

    - the relief pattern that was metalized anew is demetalized anew in regions that are not protected by resist coating,
    or that

    - a microrelief pattern, especially a diffractive microrelief pattern, is embossed in the resist coating,

    - the relief pattern is metalized anew,

    - a high-viscosity resist coating is transferred anew, and

    - the relief pattern that was metalized anew is demetalized in regions that are not protected by resist coating.
15. The method according to at least one of claims 1 to 14, characterized in that the relief pattern is provided with spacing marks for setting a defined spacing and/ or pressure when transferring the imprint material, and/or that the relief pattern is provided with indicator marks that are measured and registered when transferring the imprint material to control inking and/or pressure, and/or that the imprint material is provided with particles of a defined size that prevent a crushing of the imprint material when transferring.
16. The method according to claim 1, characterized in that, with the printing tool, an imprint material, especially a low-viscosity imprint material, is selectively transferred substantially only into the depressions of the relief pattern.
17. The method according to claim 16, characterized in that, in selecting the low-viscosity imprint material, the surface tension of the imprint material is coordinated with the surface energy of the relief pattern, and/or that an imprint material having a viscosity between 3 mPa*s and 1500 mPa*s at room temperature is chosen.
18. The method according to at least one of claims 16 to 17, characterized in that a printing ink, especially a dye solution, a pigment dispersion or an ink is chosen as the imprint material.
19. The method according to at least one of claims 16 to 18, characterized in that a liquid crystal solution, especially a low-viscosity liquid crystal solution is chosen as the imprint material, preferably that the depressions of the relief pattern are developed having alignment patterns for aligning liquid crystals.
20. The method according to at least one of claims 18 to 19, characterized in that, first, a low-viscosity printing ink or liquid crystal solution having a low binder content is transferred that selectively flows into the depressions of the relief pattern, and in that a solution having a high binder content is then transferred that fixes the printing ink or liquid crystal solution in the depressions of the relief pattern.
21. The method according to at least one of claims 16 to 17, characterized in that a low-viscosity adhesive is chosen as the imprint material, or that a low-viscosity resist coating is chosen as the imprint material, and/or that an effect-pigmented imprint material is chosen that preferably exhibits luminescent pigments, thermochromic pigments, metal pigments and/or pearlescent pigments as the imprint material.
22. The method according to at least one of claims 16 to 21, characterized in that different low-viscosity imprint materials are transferred, especially imprint materials of different colors or provided with different effect pigments.
23. The method according to at least one of claims 16 to 22, characterized in that the imprint material is transferred in such a small amount that, when transferring, it flows only into the depression edge regions that immediately surround the elevations, or that before the desired imprint material is transferred, a low-viscosity clear lacquer that fills the depression edge regions that immediately surround the elevations is transferred in a small amount.
24. The method according to at least one of claims 16 to 23, characterized in that the depressions are developed having rounded transitions to the elevations, and/or that the elevations of the relief pattern are provided with a lotus pattern to produce lightly crosslinkable elevation surfaces.
25. The method according to claim 1, characterized in that, in a first step, a first high-viscosity imprint material is selectively transferred substantially only onto the elevations of the relief pattern, and in a second step, a second low-viscosity imprint material is selectively transferred substantially only into the depressions of the relief pattern.
26. The method according to at least one of claims 1 to 25, characterized in that through the elevations and depressions of the micropattern, micropattern elements having a pattern depth between 0.5 µm and 20 µm, preferably between 1 µm and 10 µm are formed.
27. An object, especially a data carrier or security element, having a micropattern produced according to one of claims 1 to 26.
28. The object according to claim 27, characterized in that the micropattern forms a motif image that is subdivided into a plurality of cells, in each of which are arranged imaged regions of a specified target image, the lateral dimensions of the imaged regions preferably being between 5 µm and 50 µm, especially between 10 µm and 35 µm, especially that a viewing grid is provided, composed of a plurality of viewing grid elements for reconstructing the specified target image when the motif image is viewed with the aid of the viewing grid, the lateral dimensions of the viewing grid elements preferably being 5 µm and 50 µm, especially between 10 µm and 35 µm,
    and/ or that the micropattern forms a motif image composed of a planar periodic or at least locally periodic arrangement of a plurality of micromotif elements or of an arrangement of micromotif elements for a modulo magnification arrangement whose lateral dimensions are preferably between 3 µm and 50 µm, especially between 10 µm and 35 µm, especially that a planar periodic or at least locally periodic arrangement of a plurality of microfocusing elements for the magnified or moire-magnified viewing of the micromotif elements of the motif image are provided whose lateral dimensions are preferably between 3 µm and 50 µm, especially between 10 µm and 35 µm.
29. The object according to at least one of claims 27 to 28, characterized in that the object is a security element, especially a security thread, a label or a transfer element, or that the object is a data carrier, especially a banknote, a value document, a passport, an identification card or a certificate.
30. A micropattern, manufactured according to the method of one of claims 1 to 26, having a relief pattern having elevations and depressions whose shape and arrangement form the pattern elements of the micropattern, and for which, with a printing tool, an imprint material is selectively transferred either substantially only onto the elevations or substantially only into the depressions of the relief pattern,
    wherin the relief pattern is formed by an embossing pattern, having elevations and depressions, or by a resist coating pattern, having elevations and depressions, wherein the elevations and depressions of the micropattern form micropattern elements having a line width between 1 µm and 10 µm.
31. A method for producing a high-resolution printing layer on a target substrate, characterized in that, with a method according to one of claims 1 to 5, a micropattern is produced in which the imprint material is selectively transferred substantially only onto the elevations of the relief pattern, and in that the micropattern thus produced is brought into contact with the target substrate and the imprint material present on the elevations of the relief pattern is transferred to the target substrate.

Images