EP3254865B1 - Characteristic and method for its production - Google Patents

Description

The invention relates to a method for producing a feature for a multilayer element, wherein a laser-sensitive substance is modified by means of laser radiation in terms of their color to produce a structuring. The invention further relates to a multilayer element wherein the feature has a base layer which is provided with a laser-sensitive substance, which is modified by means of laser radiation in terms of their color so that a colored structuring is achieved. The invention further relates to a security element, such as security paper or security film, with such a feature as well as a value document or a data carrier, in particular a banknote or an identity document.

Identification documents, such as credit cards or identity cards, are often laser engraved with an individual identifier. The production of continuous openings in value documents, eg banknote papers, by laser cutting has also been known for some time. For example, in the document DE 4334848 C1 describes a security with a closed by a transparent cover film window-like opening, which can be generated by a laser cutting process.

The WO 2009/003587 A1 describes a manufacturing method and a corresponding security feature that is produced by a laser cutting method by irradiating laser radiation from an upper side onto the carrier. The support of the security feature is previously coated on top with a marker which changes color by the action of laser beams. To make the hole or holes, a cutting laser beam is used whose intensity is in the radiation cross section non-uniform, for example Gaussian, is distributed. This drop in intensity produces an edge at the top at which the support is no longer cut, but a modification of the marking substance with regard to its color effect takes place. In this way, the edge region of the hole produced by means of laser radiation appears colored at the top. This effect is from the WO 2011/154112 A1 and WO 2010/07232 A1 known. A colored border of holes is also from the WO 2009/003588 A1 known.

Laser radiation-sensitive markers are known, for example, from the following publications: EP 1657072 B1 . EP 2332012 B1 . EP2528742 B1 . US 7270919 . US 7485403 . US 7998900 . US 8021820 . US8048608 . US8048605 . US 8083973 . US 8101544 . US 8101545 . US 8105506 . US 8173253 . US 8178277 . US 8278243 . US 8278244 and US 842028 ,

From the EP 1641627 B1 A method for applying markings on both sides of a security paper is known, wherein the processing takes place from one side. In order to provide the page opposite side of the paper with a security mark, laser radiation is irradiated through the paper, wherein the laser radiation ablated on the opposite side applied photosensitive layer or changed in color. The WO 98/36913 is also concerned with the creation of security markings on both sides of a security paper, using a laser beam which simultaneously performs an ablation on the front and back of the security paper so as to produce identical markings on both sides.

The DE 102010053052 A2 discloses a data carrier containing a marking produced by the action of laser radiation, which produces a different visual impression when viewed, than in a plan view.

The DE 102008046513 A1 discloses a security element which is partially provided with a metallization. Above these sections and also next to it, a laser-sensitive marking substance is applied as a coating. By means of laser radiation, a deliberate color change in the coating is produced in the areas next to the metallization. Sections in which the coating overlies the metallization are also laser treated in such a way that both the coating and the metallization are removed. Thus, a negative pattern is generated in the metallization, which is due to the targeted introduction of the laser radiation in perfect registration to the adjacent areas in which the color change was triggered on the coating.

In DE 10 2008 019092 A2 A method of describing a method according to the preamble of claim 1, wherein a security element is applied to a substrate having a marker region. With a laser beam lines of weakness are introduced into the security element, wherein - destroyed by the Gaussian intensity distribution within the laser beam - in the center of the line of weakness of the marker and color is changed at the edge of the line of weakness of the marker.

The object of the invention is to further improve a feature with regard to the security against imitation and / or to simplify the manufacturability.

This object is solved by the subject matter of the independent claims. The dependent claims are directed to preferred embodiments.

Claim 1 defines a method according to the invention. An (inner or outer) contour of the motif area advantageously follows the contour of the pattern produced - in particular at a uniform distance, so that an edge region with the width of the uniform spacing is formed.

The laser-sensitive substance is usually arranged in a laser-sensitive layer which lies below the opaque layer and above a base material layer. The laser-sensitive substance may alternatively be present in a base material layer. It is particularly advantageous if the laser-sensitive substance is printed on a base material, for example if a printed laser-sensitive layer is present on a base material layer. On the base material layer, which is optionally a carrier layer, a printed laser-sensitive layer may be provided. The base layer comprises the laser-sensitive substance at least in the region of the pattern, preferably in an area that extends beyond the pattern. The laser-sensitive region of the base layer particularly preferably extends at least 1 mm, in particular at least 2 mm, far below the not removed opaque layer. In other preferred embodiments, the laser-sensitive region of the base layer extends laterally beyond the opaque layer.

The proposed solutions are suitable for producing a visual feature with high quality, in particular independent of a possible variation of the layer thickness of the opaque layer. The feature is preferably a security feature.

In a particularly simple embodiment, the colored structuring is that (in places or) in some areas the laser radiation Color effect in the laser-sensitive substance does not trigger. This can be done, for example, by the fact that the parameter influencing the structuring of the laser radiation is the intensity of the laser radiation. There are at least two options for this. On the one hand, the intensity can be selected so that the laser radiation ablates the opaque layer in the entire pattern, but in places the radiation energy for triggering the color effect, ie the modification of the laser-sensitive substance, is insufficient. Thus, no color effect is triggered at these points, so that these (places) areas determine the structuring of the colored area in the pattern. This option is particularly advantageous if the laser-sensitive substance is provided in the entire base layer. On the other hand, in particular if the laser-sensitive substance is applied to the carrier in a coating lying under the opaque layer, the intensity of the laser beam in the pattern is locally adjusted in such a way that not only the opaque layer is removed, but also the coating with the laser-sensitive substance , At this point, because of the lack of laser-sensitive substance, no color effect can occur. At other points, the intensity of the laser radiation is adjusted in such a way that the color effect is triggered so that overall the colored structuring within the pattern is established. In these remaining places, which are to be subsequently colored, the intensity of the laser beam is adjusted so that the opaque layer is removed and the underlying coating is modified in terms of the color effect. This second option is particularly insensitive to fluctuating laser intensities because only care must be taken to ensure that the intensity is above an ablation threshold at the locations where the coating is to be removed. It can be almost anything.

The concept according to the invention provides that, due to the setting of the parameter of the irradiation of the laser radiation within the pattern, in some places the color effect to which the laser-sensitive substance is capable is preferably not triggered, but the laser radiation in the entire pattern removes the opaque layer , The pattern begins - by removing the opaque layer - exactly flush with the opaque layer. In addition, the connection of the steps of removing and dyeing the edge area, ie z.b. the non-stained area, within the pattern, fitted snugly with the stained area of the pattern.

The parameter may thus include the irradiation (J / m ² ), which is often referred to as fluence in laser technology. The fluence can be varied by varying an irradiation area (focusing / defocusing of the beam), an irradiation time (residence time / moving speed of the beam), a pulse duration (in pulsed mode) and / or a radiation intensity. The structuring is produced, for example, by the radiation intensity within the pattern remaining below a threshold in certain regions, the threshold for a partial step of the modification, in particular a specific color modification, activation or deactivation, of the laser-active substance having to be exceeded, and / or for one Sub-step of the layer removal must be exceeded.

The inventive method can also be used in a multi-stage irradiation of laser radiation. So is from the already mentioned EP 2528742 B1 a laser-sensitive substance is known, which is colored with a multi-stage process, here a three-stage process. Two-stage systems are also known to the person skilled in the art, for example in which a first stage activates the laser-sensitive substance and (at least) a second stage the color change triggers. It is now possible to remove the opaque layer with the laser radiation according to the first step in the pattern and to activate the laser-sensitive substance in the entire pattern. The second stage of irradiation of the laser radiation, which usually takes place at a different wavelength, then causes the triggering of the color effect with the desired structuring within the pattern. The laser radiation of the plurality of stages can be effected in succession in time, for example when passing through a processing section, or also simultaneously in time through a corresponding radiation mixture.

Furthermore, it is possible that the removal of the opaque layer takes place only in one stage or successively in several stages. This will open at least the following two options. In a first step, laser radiation is irradiated so that the opaque layer is removed in the entire pattern and the laser-sensitive substance is activated within the entire pattern. With a second and, if appropriate, third stage, the desired colored structuring is then generated within the pattern by means of continuously activated laser-sensitive substance. In another option, in the first stage, only parts of the pattern are formed by removing the opaque layer. In these parts, the laser-sensitive substance is activated. In a second and optionally third stage, the remaining part of the pattern is then formed by removing the opaque layer and at the same time staining the activated regions. In this procedure, the non-colored areas in the colored pattern are those in which the laser radiation in the first stage does not (yet) remove the opaque layer in the pattern and in which the opaque layer is patterned only in the subsequent stages of irradiation of the laser radiation was removed.

In particularly advantageous embodiments, a layer-removing laser radiation and - preferably subsequently - a coloring laser radiation is irradiated. A parameter of the stratifying laser radiation may be varied to partially perform a laser sensitive substance modifying substep (e.g., activate, stain). The final color is achieved in this area by the coloring laser radiation as the second laser-sensitive substance modifying substep. Alternatively or additionally, a parameter of the coloring laser radiation can be varied in order to carry out a partial step of the layer removal in regions. The opaque layer is thus at least partially removed by the coloring laser radiation. A wavelength of the layer-removing laser radiation, the material of the opaque layer and / or the laser-sensitive substance can be chosen so that the laser-sensitive substance is influenced by this wavelength, in particular color-modified, activated or deactivated. For example, a substance which can be modified in the visible and / or UV range can be selected as the laser-sensitive substance in order to remove the opaque layer with a UV laser beam. By way of example, the opaque layer could, for example, be chosen so that it can be removed with a laser beam in the IR range in order to enable a coloration with IR and / or UV laser beams.

The layer-removing laser radiation can be chosen so that it removes a predetermined layer thickness. The average layer thickness may be selected as the predetermined layer thickness, but the predetermined layer thickness is preferably less than the average layer thickness. The coloring laser radiation is suitably chosen so that it removes in the area the remaining tolerance-related components and / or the remaining layer thickness of the opaque layer. The tolerance-related proportions are determined primarily by the tolerances of the thickness of the opaque layer. By contrast, the remaining layer thickness is determined by a predetermined layer thickness selected to be less than the average thickness.

In a further variant, a wavelength of the layer-removing laser radiation, the material of the opaque layer and / or the laser-sensitive substance are chosen so that the laser-sensitive substance is not affected by this wavelength, in particular not color-modified, activated or deactivated. For example, a substance which can be modified in the visible and / or IR range is selected as the laser-sensitive substance in order to remove the opaque layer with a UV laser beam. Similarly, the opaque layer could be chosen so that it can be removed with a laser beam in the visible range to allow coloration with IR and / or UV laser beams.

Of course, the generation of the pattern and the colored structuring according to the invention within the pattern can also be combined with the production of colored structures next to the opaque layer, even if the laser-sensitive substance was also provided there. The method is then analogous to that of the already mentioned DE 102008046513 A1 whose disclosure content is therefore fully included in this regard. Since, according to the invention, the pattern is produced in the opaque layer, it is of course also possible to produce the pattern in an opaque layer which already structurally implements another security feature, for example a holography structure, etc. The invention achieves a perfect registration of a color structured pattern in the opaque layer, to the security features, which provides the opaque layer elsewhere, ie outside the pattern.

Of course, the invention is not limited to the fact that a color effect is either triggered or not. It is equally possible that instead of a yes / no effect of the laser radiation, the color effect in the sense of gradation can be graded. This can be achieved, for example, the variation of the fluence of the laser beam, i. then the intensity of the laser beam is varied to produce different intense color changes or brightness values of the color.

Particularly preferred is an opaque layer in the form of a metallization, since such metallization for other security features are already widely used. Such security features can be further developed by the internally colored structured pattern with regard to protection against counterfeiting.

It should be understood that the pattern and / or patterning may provide motifs or alphanumeric characters. In particular, the pattern may represent an individual number, such as a serial number or personalization information of the data carrier.

The marking substance need not be further structured or specially applied for the registration between color and hole / depression. It is even possible to provide the marking substance over the entire area in a much larger area than the surface treated with laser radiation occupies.

As a marker material come into question with advantage whose visible color is changed by the action of the laser radiation. For example, thermoreactive colored pigments such as ultramarine blue can be used for this purpose. Advantageously, also markers can be used be whose infrared-absorbing properties or their magnetic, electrical or luminescent properties are changed by the action of the laser radiation. It is also possible to use a combination of different marking substances, for example in order to enable both a visual and a machine authenticity check of the security feature. When using several markers, these can come to lie next to each other as well as in different layers one above the other.

According to an advantageous variant of the invention, laser radiation-modifiable effect pigments are used as the laser-radiation-modifiable marker. Such effect pigments are available to the person skilled in the art with different properties, in particular with respect to their body color, the color change under laser radiation, the threshold energy and the required laser radiation wavelength. Also, effect pigments which change not only their visible color under laser radiation but their infrared-absorbing, magnetic, electrical or luminescent properties are known to the person skilled in the art. The modification of the effect pigments can be carried out with laser radiation in the ultraviolet, visible and / or infrared spectral range, for example with a diode laser, an Nd-doped solid-state laser or a CO2 laser, in particular with a wavelength of 10.6 μm.

Particularly preferably, the laser radiation is generated at least partially by a plurality of diode lasers. The diode lasers can be arranged next to one another in at least one row; more preferably, a plurality of rows of diode lasers arranged next to each other are provided. The plurality of diode lasers simultaneously generate a plurality of independently controllable laser beams. Particularly preferred is a variety used by diode lasers at least as modifying laser radiation. Preferably, the opaque layer (choice of material, thickness and / or application) may be adapted to a diode laser as the source of the removing laser radiation. Alternatively, for example, the radiation of an Nd-doped solid-state laser or a CO2 laser can be used as laser radiation removing the opaque layer.

In a further likewise advantageous variant of the invention, a pigment-free laser-radiation-modifiable marker is used. Pigment-free marking substances can also be applied to the support, for example as a stich or printing ink. With pigment-free markers, it is possible to produce a coating of high transparency into which a high-speed, high-intensity marking can be introduced by laser action at high speed. Pigment-free marking substances can be modified by laser radiation in the ultraviolet, visible or infrared spectral range, for example with the 10.6 μm radiation of a CO2 laser. Specific, non-limiting examples of pigment-free laser-modifiable markers are in the references WO 02/101462 A1 . US 4343885 and EP 0290750 B1 specified, the disclosure of which is included in the present description in this regard.

The present multi-layer element may comprise a feature produced by the described methods. It may be part of a security element - with or without its own carrier layer - which is provided for example for security papers, documents of value and the like. Such security elements can be applied as a strip or patch on the security paper, value documents and the like. In particular, a security paper for the production of value documents or the like can be produced with a method according to the described method Be provided security feature. A value document or data carrier, in particular banknote or identity document, may comprise the described multilayer element or the described security element with the multilayer element.

As far as the terms "front" and "back" are used in this description, they refer to the irradiation of the laser radiation. The front side is the side on which the laser radiation is irradiated, the back side is the opposite side of the carrier. The carrier is flat. The terms front and back have nothing to do with a later use of the wearer. The term choice is not intended to imply that one of the pages must or may not have a particular meaning for use. Insofar as the terms "above" and "below" are used in this description, this position specification also refers to the direction of incidence of the laser radiation.

The term "color" is not limited to a colorful impression, but may also include achromatic hues, such as white and black, or grayscale, and the change between transparent and opaque. The structuring can be a single-color structuring with at least one chromatic color, possibly with a plurality of brightness values (and / or transparency values). However, the structuring is preferably a multicolor structuring which comprises at least two different chromatic colors, and / or a structuring with a plurality of brightness values (and / or transparency values). Particularly preferably, the structuring comprises an edge region in an uncoloured color and a motif region in at least one chromatic color, wherein the motif region has at least two different chromatic colors and / or several brightness values.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.

• Fig. 1 eine Draufsicht auf eine Banknote mit einem Sicherheitsmerkmal,
• Fig. 2 eine Schnittdarstellung durch eine erste Ausführungsform des Sicherheitsmerkmals der Banknote der Fig. 1 während der Herstellung,
• Fig. 3 eine Schnittdarstellung ähnlich der Fig. 2 nach Abschluss der Herstellung,
• Fig. 4 eine Draufsicht auf das Sicherheitsmerkmal,
• Fig. 5 eine Darstellung ähnlich der Fig. 2 für eine zweite Ausführungsform,
• Fig. 6 eine Darstellung ähnlich der Fig. 3 für eine erste Variante der zweiten Ausführungsform,
• Fig. 7 eine Darstellung ähnlich der Fig. 6 für eine zweite Variante der zweiten Ausführungsform,
• Fig. 8 eine Darstellung ähnlich der Fig. 2 für eine dritte Ausführungsform, bei der eine mehrstufige Farbänderung in einer laseraktiven Substanz ausgeführt wird,
• Fig. 9 eine Darstellung ähnlich der Fig. 8 in einer zweiten Bearbeitungsstufe,
• Fig. 10 eine Schnittdarstellung ähnlich der Fig. 7 für das Sicherheitsmerkmal nach Abschluss des mehrstufigen Farbmodifikationsprozesses,
• Fig. 11 eine Schnittdarstellung einer optimalen Gestaltung, die für alle Ausführungsformen in Frage kommt,
• Fig. 12 eine Draufsicht auf ein Sicherheitsmerkmal mit einer ersten Anordnung des Musters,
• Fig. 13 eine Draufsicht auf ein Sicherheitsmerkmal mit einer zweiten Anordnung des Musters, und
• Fig. 14 eine Draufsicht auf ein Sicherheitsmerkmal mit einer dritten Anordnung des Musters.

Show it:

• Fig. 1 a top view of a banknote with a security feature,
• Fig. 2 a sectional view through a first embodiment of the security feature of the banknote of Fig. 1 During manufacture,
• Fig. 3 a sectional view similar to the Fig. 2 after completion of the production,
• Fig. 4 a top view of the security feature,
• Fig. 5 a representation similar to the Fig. 2 for a second embodiment,
• Fig. 6 a representation similar to the Fig. 3 for a first variant of the second embodiment,
• Fig. 7 a representation similar to the Fig. 6 for a second variant of the second embodiment,
• Fig. 8 a representation similar to the Fig. 2 for a third embodiment in which a multi-level color change is carried out in a laser-active substance,
• Fig. 9 a representation similar to the Fig. 8 in a second processing stage,
• Fig. 10 a sectional view similar to the Fig. 7 for the security feature after completing the multi-level color modification process,
• Fig. 11 a sectional view of an optimal design, which is suitable for all embodiments,
• Fig. 12 a top view of a security feature with a first arrangement of the pattern,
• Fig. 13 a plan view of a security feature with a second arrangement of the pattern, and
• Fig. 14 a plan view of a security feature with a third arrangement of the pattern.

The invention is explained using the example of a security feature as a feature on a banknote as a value document. Fig. 1 shows a schematic representation of the banknote 10, a based on the Fig. 2-14 has security feature 12 explained in more detail.

The security feature 12 of the multilayer element comprises an opaque layer in which a pattern is formed by the layer in the form of this Pattern was removed. Furthermore, the interior of the pattern is colored. In the following, various embodiments will be described in which this pattern and the colored structuring is produced using a laser-sensitive substance and laser radiation suitable for this purpose. The embodiments here have in common that at first an unstructured (or not yet structured) opaque layer is applied and this is then removed by means of laser radiation. The laser radiation used here also contributes to the generation of the colored structuring within the pattern.

In a first embodiment, which will be described below with reference to Fig. 2 to 4 is described, a laser-sensitive substance is used, which shows a change in color when irradiated with laser radiation of a certain wavelength above a certain fluence value. The laser radiation, which produces the pattern, thereby generates the colored structuring within the pattern by means of suitable intensity modulation.

The method begins with the provision of a carrier 14, which has a laser-sensitive substance 18. Here and below, the example of a carrier is used as the base layer. However, a carrier (layer) is only an optional element of a base layer of the present multi-layer element. The base layer may be a substrate layer of a data carrier, ie the banknote 10. Alternatively, the base layer is a layer of a separate security element, such as security tape or patch. In the embodiment of the FIGS. 2 and 3 this laser-sensitive substance 18 is incorporated in the carrier 14. It can, as will be explained below with reference to another embodiment, also be applied to the carrier 14. Above the laser-sensitive substance 18, in this case incorporated in the carrier 14, there is an opaque layer, in the embodiment in the form of a metallization 16. This is initially still unstructured, as regards the color pattern to be designed. The metallization 16 is removed by means of a laser beam 20 emitted by a beam source 22 in a pattern. Fig. 3 shows the manufactured pattern 24 as a simplified example of an opening. Of course, a shape of the pattern 24 may be selected which encodes information, since the pattern 24 ultimately forms a negative mold in the metallization 16.

The intensity of the laser radiation is set in the removal of the metallization 16 in the form of the pattern 24 so that in some areas a color change 26 in the laser-sensitive substance in the carrier 14 is triggered. Other areas, in this example in the form of a gap 28 between the color change 26 and the edge of the pattern 24, have no color change, since there the laser energy is such that in the laser-sensitive substance 18 no color change is triggered.

The result is shown in plan view Fig. 4 clear. The section line AA, along which the Fig. 3 is shown in Fig. 4 entered. Fig. 4 shows the security feature 12 with the pattern 24, here in the example of a stylized "P". Inside this negative mold, the pattern 24 is colored in color by a color change 26 which is not completely identical to the outline of the negative mold according to pattern 24 - in this case due to the gap 28. Other structuring is of course possible. The metallization 16 has not been removed in a pattern adjacent to the pattern, here the pattern 24 surrounding metallization 29. Other divisions between metallization area and pattern are possible. The structuring within the pattern 24 is ultimately dictated by the properties of the laser beam 20, so that a corresponding control provides a desired structuring of the area provided with the color change 26 within the pattern 24 sets. The gap 28 may also be referred to as the edge area (of the pattern) and preferably encloses the color change 26. The color change 26 may also be referred to as the motif area (of the pattern). In particular, the motif area could represent a brightness-graded and / or multicolored motif.

In the embodiment of the FIGS. 2 and 3 As already mentioned, it is also possible to apply the laser-sensitive substance 18 in a separate coating 30 to the carrier 14, such as Fig. 5 shows. Again, located above the laser-sensitive substance 18 (here in the form of the coating 30) is a metallization 16, which in turn is removed in the form of the pattern 24 by means of the laser beam 20.

In order to create the structuring of the color change 26 with the laser beam, there are two possibilities here. On the one hand, the laser radiation can be adjusted so that not only the metallization 16 but also the coating 30 with the laser-sensitive substance 18 is removed at those points where no color change 26 is to take place. The gap 28 thus extends through the coating 30. This is in Fig. 6 shown. On the other hand, in the gaps 28, ie at those points where no color change 26 is to take place, the intensity of the laser beam 20 remains below the threshold value which the fluence must exceed in order to produce the color change 26. The gap 28 thus consists of coating 30, which has not been modified by means of laser radiation to a color change. The gap 28 is exactly adjacent to the remaining metallization 16, regardless of any tolerances, in particular a layer thickness of the metallization 16 and / or the fluence of the laser beam 20. Since the color change is also generated by the laser beam, a given, in particular uniform, width of the gap 28 can be ensured. The gap 28 is thus seen by the viewer as a registration-specific border area for the color change 26 (the motif area of the pattern).

In both variants of this embodiment, ie in 6 and 7 , as well as in the embodiment in which the laser-sensitive substance 18 is incorporated in the carrier 14, a structuring of the colored impression is achieved in the pattern 24 (eg by color change 26 and gap 28). The color change 26 is itself in turn substructured, by means of several brightness levels and / or several colors.

Of course, it is also possible to provide the laser-sensitive substance 18 both in a coating 30 and in the carrier 14.

In the embodiments of the Fig. 2 to 7 the color change in the laser-sensitive substance takes place by adjusting the intensity of the laser beam, ultimately the area density, ie fluence, at the surface of the material to be processed. However, the intensity is not the only parameter that can be varied in the introduction of the laser radiation in order to achieve the colored structuring within this pattern in connection with the creation of the pattern 24. Ultimately, the parameter depends on the laser-sensitive substance. In the case of a laser-sensitive substance, which can be brought to color change only in a very narrow band, for example within a certain absorption band, the variation of the laser radiation wavelength could also be used as a parameter. The same applies to a variation of the polarization.

The Fig. 8 to 10 refer to a further embodiment in which the laser-sensitive substance in particular in a multi-stage process for Color variation can be brought. Such a multi-stage process is for example from the already mentioned EP 2528742 B1 known. The laser-sensitive substance disclosed therein can be modified by a three-stage process so that a multicolor is possible. In the Fig. 8 to 10 an embodiment is shown in which a two-step process is performed. The two-step process in this embodiment is that a laser-sensitive substance 32 must first be activated with an activation laser beam 34 before being modified in color with a color-changed laser beam 38. In a three-stage process, two color-changing laser beams would be used, which cause a different color change and thus can produce a multicolor in the laser-sensitive substance 32. The layer-removing activation laser beam 34 and the at least one color-changing laser beam 38 are generated by respectively different lasers, ie at least two laser sources. For ease of explanation, the embodiment of the Fig. 8 to 9 on only one color-changed laser beam 38.

First, the coating 30 is again provided on the support 14, which now however contains the laser-sensitive substance 32, which is to be color-changed in a two-stage process. Alternatively, the substance 32 is provided in the carrier 14 above the substance 32 is again an opaque layer, here also exemplarily in the form of a metallization 16th

Now, in an initial stage of the color change, an activation laser beam 34 is applied so that on the one hand the pattern 24 is created in the metallization 16 and on the other within the pattern, the laser-sensitive substance 32 is converted into an activated form, so that in the pattern 24 laser-activated Substance 36 is present. Only optional can be analog to Fig. 1 a parameter of the laser beam - here preferably its fluence - are varied in order to generate an unactivated edge region within the pattern.

In a subsequent step, the color-changing laser radiation 38 selectively performs a color change on the activated substance 38, only those points within the pattern 24 being illuminated with the color-changed laser beam 38 at the appropriate intensity and wavelength at which the color change 26 is produced should. In the gaps 28, the color-changing laser beam 38 is either not irradiated at all or with other parameters that do not lead to the color change. Thus, in this way within the pattern 24, in turn, a colored structuring (in the example by color change 26 and gap 28) and within the color change 26 a substructure is obtained.

In the above embodiments, it was primarily used that a color effect was either triggered (color change 26) or not (gap 28). However, the embodiments are not limited to such a yes / no effect of the laser radiation as Fig. 11 shows. There it can be seen that the pattern 24 or its motif area 40, 42, 44 is internally colored differently structured. It has gaps 28 (as a border area) and areas 40 with high-intensity color change, areas 42 with medium color change and areas 44 with slight color change. These areas were created by varying the fluence of the laser beam. In the embodiment of the FIGS. 2 and 3 this is the fluence of the laser beam 22 which forms the pattern 24 in the metallization. The same applies to the embodiments according to Fig. 5 to 7 , In the embodiment of the Fig. 8 to 10 the intensity of the color-changed laser beam 38 would vary accordingly. The same applies, of course, to the desired multicolor.

Was shown in the previous embodiments - as in Fig. 4 - a metallization 16 (as an opaque layer) with an internal pattern 24. The opaque layer forms a negative shape - or a completely around the pattern 24 reaching boundary - for the pattern 24. The non-removed portion 29 of the opaque layer thus has a Inner contour, which corresponds to the pattern, and optionally a - in particular by laser radiation not changed - outer contour. However, it is also conceivable that the remaining (not removed) opaque layer is arranged completely or partially within the pattern.

The multi-layer structure of the figures described, in particular also the Figures 2 . 5 and 8th 12 may include further optional layers, which are, for example, optional sublayers of layers 14, 16 (and 30), and / or disposed as optional interlayers between layers 14, 16 (and 30).

For example, an intermediate layer can be arranged on a substrate as the base layer 14, in particular a primer or a further ink-conducting printed layer. The laser-sensitive coating 30, which is optionally arranged on the intermediate layer, may contain different laser-sensitive dyes in different partial layers. The opaque layer 16 may be a multilayer transfer element. Transfer elements, such as patches or security strips, are applied to an existing structure, in the present example comprising layers 14 and 30. On the coating 30, a transparent intermediate layer, in particular a heat-sealing layer and / or a carrier film layer may be arranged. The opaque layer 16 may in particular also be a multi-layer structure with a color-shift effect, for example made of an opaque, a transparent one (eg SiO2) and a semitransparent (eg chromium) sublayer exists (possible as 3- or 5-layer structure). The opaque layer 16 can be arranged on a further transparent layer, such as a lacquer layer, in particular an embossed lacquer layer. Likewise, one or more preferably transparent cover layers, for example, in turn, a lacquer layer, may be arranged on the opaque layer. Combinations of the just mentioned further layers (optionally as parts of a transfer element) are provided.

One or more layers of the structure in the figures, ie the layers 14 (and 30) and 16 or their partial or intermediate layers can be structured in height. Accordingly, one or more layers of the structure can compensate for a height structuring, that is to say be arranged on a height structuring, but have a surface which is not level-structured. The height structuring may preferably be effected by embossing, for example microembossing of a diffractive structure, mirror structure or lens structure, but alternatively also by a printing process, in particular intaglio printing or finely structured printing. In particular, the opaque layer 30 may be height-structured, for example as a reflective (metal) layer on a lacquer layer with micro-embossing, z. a hologram or a micromirror structure.

Based on FIGS. 12 to 14 In the following, various arrangements of the pattern to the opaque layer will be described, the pattern being repeated after each of the following FIGS. 2 to 11 described method variants can be created.

Fig. 12 shows the security feature 12 with a first pattern 24, which has a border area, for example as a gap 28, and a motif area with a color change 26 in the form of a multicolor image. The first pattern 24 is bounded by the inner contour 41 of the metallization region 29, which in particular also has an outer contour 42. A second pattern 24 'having a monochrome edge region 28' and a motif region 26 'embodied in a plurality of, indicated three different brightness levels, can be contained in the security feature 12 and in particular generated as described above. Edge regions 28, 28 'are preferably of uniform color, in particular in white or in a bright, chromatic color. Also, the second pattern 24 'is bounded by an inner contour 41' of the metallization 29 in its entirety.

The inner contour 41, 41 'is generated by the removing laser irradiation. The outer contour 42 remains unchanged, ie corresponds to the original outer contour of the metallization region 29.

In Fig. 13 is the pattern 24 shown, the motif 46 is only partially within the metallization 29.

In the region of the pattern 24, the metallization 16 is removed. The three non-removed regions 29 of the metallization 16 have outer contour sections 42 which correspond to the original outer contour of the metallization, and inner contour sections 43 which adjoin the pattern 24 in register. Only the inner contour sections 43 are generated by the removing laser irradiation.

The pattern 24 comprises at least one edge region 28, in the present case there are three edge regions 28, and the motif region 26. An overall motif 46 comprises the motif region 26 and at least one outer region 47. The outer regions 47 lie outside the metallization 16. In the, here three, outer regions 47, the motif of the motif area, in particular the colored structuring is continued. The pattern 24 and the motif area 26 are generated by means of laser radiation as described above. The exterior areas 47 of the motif are generated together with the motif area 26. The motif 46 is also generated in the outer region 47 by the at least one laser step / partial step, which modifies the laser-sensitive substance in the motif region 26.

A third possible variation of the arrangement of the pattern shows Fig. 14 , In this arrangement, the metallization region 29 lies completely within the pattern 24.

The metallization region 29 has an outer contour 42 produced by the removing laser radiation. The original outer contour of the metallization region 29 is shown as a dashed line. The edge region 28 of the pattern 24 preferably completely encloses the metallization region 29. The edge region 28 is preferably designed in a uniform color, in particular in white or in a bright color. In the motif area 26, a motif is shown in several colors and / or in several brightness levels, for example a true color image.

The motive produced by modifying the laser-sensitive substance by means of laser radiation optionally comprises, as an overall motif 46, an outer region 47 and the motif region 26 of the pattern 24 (as inner region). The at least one outer region 47 lies completely outside the metallization, ie in particular outside an original outer contour of the metallization. The modification of the laser-sensitive substance in the outer region 47 and in the motif region 26 takes place together, ie by means of the same laser (partial) steps / s.

In advantageous variants of this arrangement, the opaque layer 16 is applied as a transfer element, with the outer contour of the pattern 24, to the laser-sensitive layer 14 (and 30). The transfer element (in particular patch) may be multi-layered and configured with and / or without carrier film. The pattern 24 is generated partly under the transfer element. The overall motif 46 produced in the laser-sensitive layer 14, 30 extends over the motif region 26, under the transfer element, up to the outer region 47, laterally next to the transfer element. Only as an example of the already mentioned possible combinations of further intermediate or partial layers a layer sequence is mentioned. Substrate (paper, foil or hybrid such as foil-paper foil) including adhesive layer / primer 14, laser-sensitive layer including optional primer layer 30 and opaque transfer element 16 with heat sealing lacquer layer, optional carrier foil, embossed lacquer layer and embossed metal layer and transparent cover layer. In other variants, the opaque layer may be printed or vapor-deposited. Combinations of the arrangements shown in a single feature are possible, as long as covered by the claims. For example, the feature may include a pattern enclosed by the metallization region, a pattern partially delimited by the metallization region, and / or a pattern with an enclosed metallization region.

LIST OF REFERENCE NUMBERS

10

bill

12

safety feature

14

base layer

16

metallization

18

laser-sensitive substance

20

laser beam

22

beam source

24, 24 '

template

26, 40, 42, 44

Basic Zone

28

border area

29

metallization

30

coating

32

laser-sensitive substance

34

activating laser beam

36

activated substance

38

color-changing laser beam

41

Inner contour metallization area

42

Outer contour metallization area

43

Interior section metallization area

46

overall theme

47

Exterior of the subject

Claims (18)

1. Method for producing a feature in a multilayer element, wherein

   - a base layer (14) provided with a laser-sensitive substance (18; 32) that is modifiable with respect to the colour thereof by means of laser radiation (20; 34, 38) is provided,

   - an opaque layer (16) is arranged on the base layer (14) provided, and

   - laser radiation (20; 34, 38) is radiated onto the opaque layer (16) such that thereby the opaque layer (20; 34, 38) is removed in a pattern (24),

   wherein a parameter of the irradiation using the laser radiation (20; 34, 38) is varied within the pattern (24) such that the modification of the laser-sensitive substance (18; 32) within the pattern (24) is varied and consequently coloured structuring (26, 28; 40, 42, 44) is produced,
   wherein the coloured structuring (26, 28; 40, 42, 44) comprises a first region (26; 40, 42, 44) and a peripheral region (28),
   wherein the peripheral region (28) of the coloured structuring (26, 28; 40, 42, 44) has a single-colour embodiment,
   characterized in that
   the first region (26; 40, 42, 44) is a motif region in which the laser-sensitive substance (18; 32) is modified differently in a plurality of colours and/or in a plurality of brightness values.
2. Method according to Claim 1, wherein the single-coloured peripheral region (28) is embodied to be uniform in terms of colour in white or a bright colour.
3. Method according to Claim 1 or 2, wherein layer-removing laser radiation and subsequently colour-imparting laser radiation are radiated in.
4. Method according to Claim 3, wherein
   the parameter of the layer-removing laser radiation is varied to regionally perform a partial step modifying the laser-sensitive substance, and/or
   the parameter of the colour-imparting laser radiation is varied to regionally perform a partial step of layer removal.
5. Method according to one of Claims 1 to 4, wherein the laser-sensitive substance (18; 32) is arranged in a laser-sensitive layer (30), located under the opaque layer (16), on the base material layer (14).
6. Method according to one of Claims 1 to 5, wherein the parameter comprises the radiation intensity and the structuring (26, 28; 40, 42, 44) is produced by virtue of the radiation intensity within the pattern (24) regionally staying under a threshold value,
   wherein the threshold value

   - must be exceeded for a partial step of the modification, in particular a predetermined colour modification, an activation or deactivation, of the laser-active substance (18; 32), and/or

   - must be exceeded for a partial step of the layer removal.
7. Method according to one of Claims 1 to 6, wherein the structuring (26, 28; 40, 42, 44) is produced by virtue of the laser-sensitive substance being removed and/or the laser-sensitive substance being deactivated regionally within the pattern (24) using the laser radiation (20; 34, 38).
8. Method according to one of Claims 1 to 7, wherein the substance is modifiable with respect to the colour thereof in a modification process comprising at least two stages.
9. Method according to Claim 8, wherein

   - in both stages, laser radiation is radiated in and the stages differ with respect to wavelength of the laser radiation (20; 34, 38), and/or

   - one of the two stages effects activation of the substance (18; 32), and the other of the two stages effects a colour change of the substance (18; 32).
10. Method according to one of Claims 1 to 9, wherein the opaque layer is a metal layer (16) which is demetallized according to the pattern (24) by irradiation using the laser radiation (20; 34, 38).
11. Method according to one of Claims 1 to 10, wherein the laser radiation is produced at least partially by a multiplicity of diode lasers and/or comprises simultaneous laser beams which are controllable independently of one another.
12. Multilayer element having a feature, comprising

    - a base layer (14) provided with a laser-sensitive substance (18; 32), wherein the laser-sensitive substance (18, 32) is modifiable with respect to the colour thereof by means of laser radiation (20; 34, 38),

    - an opaque layer (16) arranged on the base layer (14),

    - wherein the opaque layer (16) is removed in a pattern (24) by way of laser radiation (20; 34, 38),

    - wherein the laser-sensitive substance (18; 32) is structurally modified within the pattern (24) by variation of a parameter of radiated laser radiation (20; 34, 38) and, as a consequence, coloured structuring (26, 28; 40, 42, 44) is produced within the pattern (24), and

    wherein the coloured structuring (26, 28; 40, 42, 44) comprises:

    a motif region (26; 40, 42, 44), which is coloured, structured in multiple colours and/or in multiple brightness values, and

    a single-colour peripheral region (28) of the coloured structuring.
13. Multilayer element according to Claim 12, wherein the feature according to one of Claims 2 to 11 is formed.
14. Multilayer element according to Claim 12 or 13, wherein the coating (30) with the laser-sensitive substance (18) is removed in the peripheral region (28) or the laser-sensitive substance (18) is unmodified in the peripheral region (28).
15. Multilayer element according to one of Claims 12 to 14, wherein the laser-sensitive substance (18; 32) is modifiable with respect to the colour thereof using colour-imparting laser radiation (20; 34) and the material of the opaque layer is removable by means of layer-removing laser radiation (20; 34),
    wherein the laser sensitive substance

    - is not influenced, specifically not modified in terms of colour, or

    - is influenced, specifically activated or deactivated,

    by a wavelength of the layer-removing laser radiation (20; 38).
16. Multilayer element according to one of Claims 12 to 15, wherein
    a non-removed region (29) of the opaque layer (16) completely surrounds the pattern (24, 24'); or
    the pattern (24) either surrounds a non-removed region (29) of the opaque layer or is delimited only sectionally by the non-removed region (29), wherein the coloured structuring is preferably continued in a region (47) outside the opaque layer (16).
17. Element, such as security paper or security foil, having a multilayer element according to one of Claims 12 to 16, wherein the feature is preferably a security feature.
18. Valuable document or data carrier, in particular banknote (10) or identifying document, having a multilayer element according to one of Claims 12 to 16 or a security element according to Claim 17.

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