Method for generating fluorescence characteristics in material using laser

Abstract

The invention provides a method (100) for generating at least partial fluorescence characteristics in a material (10). The method (100) comprises providing (110) a material (10); providing (120) a laser (20); arranging (130) the material in the beam path of the laser (20) such that the laser (20) can selectively illuminate the material in sections; and irradiating (140) the surface (11) of the material (10) at least in sections with a laser (20). The surface (11) of the material (10) is irradiated (140) with the laser (20) over a long period of time at least in sections until visible smudging traces (12) are formed on the irradiated region (13) of the surface (11) of the material (10), whereby a fluorescence characteristic is generated in the irradiated region (13).

Description

Technical Field

[0001] The present invention relates to a method of producing fluorescent properties in a material using a laser. Background Art

[0002] Card-shaped data carriers such as identity cards (e.g. identity cards and driver's licenses), data pages in passports, payment cards (e.g. credit cards, debit cards, etc.), and valuable documents such as banknotes usually have a plurality of security features in order to increase the security against counterfeiting. Such security features include, for example, holograms, laser tilted images, color tilt effects (e.g. optically variable colors), security threads, contrast reversal effects, microprinting, guilloché patterns, UV embossing, 3D effects and fluorescent features, just to give a few examples. In this case, in particular, fluorescent features are usually achieved by inserting fluorescent pigments, which are contained, for example, in printing pigments, films, inks, etc. Card-shaped data carriers such as identity documents usually consist of a multilayer structure, in which different opaque and transparent layers are laminated together. In order to achieve, for example, a fluorescent effect in the security feature, the corresponding pigments are usually inserted into the layer structure between suitable layers and laminated together or applied to the surface. Therefore, it is necessary to insert additional substances into the material or apply them to the material. Summary of the invention

[0003] SUMMARY OF THE INVENTION The object of the present invention is therefore to generate at least a partial fluorescent effect in a material without introducing additional substances into the material.

[0004] This object is achieved according to the invention by a method for producing at least partial fluorescent properties in a material. Exemplary embodiments emerge from the following description.

[0005] According to one aspect, a method for generating at least partial fluorescent properties in a material is provided. The method comprises: providing a material; providing a laser; arranging the material in a beam path of the laser so that the laser can selectively and sectionally irradiate the material; and irradiating the surface of the material at least sectionally with the laser. The surface of the material is irradiated at least sectionally with the laser for a long time until a smoke mark is formed on the irradiated area of ​​the surface of the material, thereby generating the fluorescent property in the irradiated area.

[0006] The invention is based on the surprising discovery that irradiation of certain materials with a laser under certain conditions changes the corresponding material in such a way that a fluorescent property is inherently transmitted / implanted into the material. Such a fluorescent property can be used, for example, as a security feature in card-shaped data carriers, such as identification cards or payment cards. The fluorescent property is produced only by irradiating the material with a laser, without the need for inserting / applying additional substances, such as corresponding pigments. This makes it possible to easily generate fluorescence, in particular also after the material, such as a card-shaped data carrier, has been produced.

[0007] Fluorescence is generally understood as the spontaneous emission of light after a material is excited by light for a short time. Here, the emitted photons are usually lower in energy than the photons absorbed before. The physical system in which fluorescence occurs is called a fluorophore. Fluorescence needs to be distinguished from phosphorescence. Unlike phosphorescence, in fluorescence, transitions between two electronic states are allowed. Therefore, the excited state has a shorter lifespan and the fluorescence extinguishes after a short time. It is assumed that irradiating a material with a laser will chemically change the material so that the material has fluorescent properties. In particular, molecules with conjugated double bonds show fluorescence because electrons move through multiple atoms here and are therefore more easily excited. Therefore, it is assumed that the material is chemically changed accordingly when irradiated with a laser under the right conditions. In particular, CO2 lasers and fiber lasers have proven to be very effective in generating fluorescence, as will be described below. However, in principle, other laser types can also be considered.

[0008] It has been shown that a certain degree of visible smoke marks on the material surface is necessary in order to produce the fluorescent properties. In this context, "smoke marks" are understood to be a certain degree of yellowing of the surface, which is produced by the laser energy introduced and the associated burning processes on the surface. These smoke marks do not necessarily have to be visible with the naked eye, but it is sufficient if they are visible, for example, through auxiliary means such as a microscope or the like. However, it has been shown that the more pronounced the smoke marks, the stronger the fluorescent properties. However, in the case of limited smoke formation, this can be removed later so that the smoke is no longer visible when viewed in daylight.

[0009] At least partial fluorescence properties are understood to be section-wise fluorescence properties on a material, which are achieved by section-wise illumination of the surface. For example, a laser can be irradiated / scanned over a specific pattern or visual object, thereby generating a corresponding fluorescence of the pattern.

[0010] To irradiate the material, the laser can be operated with a suitable laser power and moved appropriately through the material (optionally at an appropriate pulse frequency of the laser). The laser power and the "sweep speed" of the surface are coordinated with one another in such a way that sufficient energy is introduced into the material to produce the appropriate chemical change, but not too much energy that could damage or destroy the material. The exact laser parameters depend on the material to be irradiated and the type of laser and can be determined, for example, experimentally. The laser parameters are usually selected correctly when a certain, but not excessive, degree of smoke marks is evident on the surface.

[0011] According to one embodiment, the laser is one of a CO2 laser and a fiber laser.

[0012] These laser types have proven to be particularly effective / useful for producing fluorescent properties, in particular in card-shaped data carriers (or in materials typically used in these card-shaped data carriers, as described below) and are therefore preferred.

[0013] CO2 lasers (or carbon dioxide lasers) are laser classes of different configurations in a group formed by gas lasers, molecular lasers and infrared lasers in the mid-infrared range. The laser medium of a CO2 laser is carbon dioxide with a 4-level system (4-Niveau-System). In principle, a CO2 laser can achieve an output power of no more than 80 kW and a pulse energy of no more than 100 kJ. A CO2 laser generates an infrared light beam having a wavelength in the (wavelength) band of 9.6 to 10.6 μm. CO2 lasers are in principle known in the prior art, so their detailed working method will not be further elaborated here.

[0014] Fiber lasers are a special form of solid-state lasers. The doped core of a glass fiber forms the active medium in a fiber laser. This refers to glass fibers with the properties of optical waveguides. The laser radiation guided by the laser-active fiber is amplified to a very high degree due to its great length. Fiber lasers are usually pumped optically by injecting the radiation of a diode laser into the cladding of the fiber core or into the fiber core itself parallel to the fiber core. Double-clad fibers allow higher powers; the pump radiation reaches the active fiber core in a distributed manner from the thick cladding. The most common doping element for the laser-active fiber core is erbium, followed by ytterbium and, for high-power applications, neodymium. Fiber lasers have unique properties, such as an electro-optical efficiency factor of more than 30%, an outstanding laser beam quality (M for single-mode fiber laser constructions) and a high-power doping factor (Nd). 2 <1.1, for double-clad optical fiber it is M 2<1.2), a long service life (>20000 h) and a compact, maintenance-free and insensitive design. Pulse operation reaches up to the fs range and can achieve high peak intensities. Fiber lasers are also known in principle, so their detailed working method will not be explained in detail.

[0015] According to other embodiments, when the laser is a CO2 laser, the CO2 laser is operated at a power between 60 W and 100 W and a wavelength of 10.6 μm. When the laser is a fiber laser, the fiber laser is operated at a power between 20 W and 30 W and a wavelength of 1064 nm.

[0016] These operating parameters have proven to be particularly effective and therefore preferred, in particular when the method is applied to card-shaped data carriers (or materials thereof). These operating parameters introduce in particular sufficient energy into the material in order to change it accordingly, thus producing fluorescent properties, without damaging the material. However, these values ​​are only exemplary and other laser parameters can also be considered in principle. The most preferred parameters also depend in particular on the material to be irradiated.

[0017] According to other embodiments, the surface of the material is irradiated with a pulsed laser.

[0018] For example, the energy introduced can also be adjusted in particular by means of the pulse frequency. For example, a fiber laser can be operated at full power at a pulse frequency of 25 kHz to 600 kHz or at a linearly reduced power at a pulse frequency of 1 kHz to 25 kHz. At a repetition frequency of 25 kHz, a pulse energy of about 0.8 mJ is generated. For example, a CO2 laser can be operated at a pulse frequency of no more than 100 kHz. However, it should be noted that in principle, the method can also be operated with a non-pulsed laser. However, a pulsed laser can control the introduced energy more precisely.

[0019] According to other embodiments, irradiating the surface of the material includes at least irradiating the surface at a first angle to produce a first fluorescence and irradiating the surface at a second angle to produce a second fluorescence, so as to produce direction-dependent fluorescence characteristics, so that the corresponding fluorescence is only visible at the corresponding observation angle.

[0020] Irradiation of a material or its surface at an angle in particular generates fluorescent properties which are visible when viewed at this angle. Thus, when irradiated at different angles, a fluorescent tilted image can be generated which has a different appearance when viewed at different angles (English: Multiple Laser Image, MLI). For example, at a first angle a person's name can be seen as fluorescent information and at a second angle the person's surname can be seen as fluorescent information. However, this is only an example and all conceivable visual objects can be selected.

[0021] It is also conceivable to illuminate the surface of the material at more than one angle in order to provide a large amount of information at different flashing angles. This configuration is particularly suitable as a security feature, for example for identity cards / documents such as identity cards, employee cards, passports, etc.

[0022] According to other embodiments, the material is a card-shaped material.

[0023] The term "card-shaped data carrier" as used herein includes all card-shaped data carriers that carry data in some form. In this context, "data" is not necessarily only digital data, but also includes printed data or other data, for example data in the form of text or images, such as citizenship data present in a passport, identity card or other identity documents. However, as an alternative or in addition, these data carriers may also include digital data, for example data stored on a card chip (such as a payment card / credit card).

[0024] In particular, a large number of anti-counterfeiting features are usually provided in identity documents. The fluorescent effect has hitherto been achieved by introducing additional substances containing fluorescent pigments (e.g. printing pigments, films, inks, etc.). Additional manufacturing steps are required for this. However, the present method can produce card-shaped data carriers without the need for additional manufacturing steps and can realize personalization after the production is completed. The advantage of using lasers to produce fluorescent effects is that no additional manufacturing steps are required, such as the introduction / application of fluorescent pigments in or on the card. In addition, the use of laser technology to produce fluorescent effects also offers the advantage of design diversity, because the fluorescent effect can be produced at any position on the front and / or back. Here, the fluorescent effect can be produced either over the entire surface or only in sections.

[0025] According to other embodiments, the card-shaped material has a layer structure which comprises a plurality of layers laminated together.

[0026] For example, the card body of a card-shaped data carrier can have a laminated structure, which includes seven layers of film (transparent film-transparent film-opaque film-transparent film-opaque film-transparent film-transparent film-transparent film). However, this is just an example, and other layer structures are also possible. The layer structure in the form of a thin sheet can be pressed by means of a laminator. The thin sheet can then be cut into each individual card body of a card-shaped data carrier. If necessary, each individual card-shaped data carrier can be punched out in the window area so that the so-called card insert can be inserted into the punched area next.

[0027] The method can be applied both to the production of a finished layer structure and to individual layers of a card-shaped material, which are then laminated together.

[0028] According to other embodiments, the card-shaped material is a card-shaped data carrier.

[0029] In addition, in such a card-shaped data carrier, but also in any other suitable data carrier or document, a black and white portrait can optionally be generated, for example, by means of a laser, and a marking can be made in such a card-shaped data carrier. For this purpose, the material of at least individual layers has corresponding carbon black particles, which block the laser beam and thus "capture" the laser energy and cause the material to change color at this location due to the laser energy. Then, the black and white portrait can also be overprinted in color by DoD (inkjet on demand), thereby forming a color portrait (the so-called CLIP ID). If necessary, a film patch with a microlens security element or a micromirror security element can also be applied. However, it should be noted that the generation of fluorescence is in principle independent of the presence of carbon black particles and can also be achieved in materials without carbon black particles. However, the disclosed method can be performed as a supplement to marking / personalization by such carbon black particles in order to achieve further personalization, for example, personalization by anti-counterfeiting features.

[0030] For example, it is also conceivable to use the method to additionally impart a fluorescent effect to visual objects or text, for example by “tracing” an image with a laser using the method, thereby further increasing the already good anti-counterfeiting security.

[0031] According to other embodiments, the card-shaped data carrier is an identity card, a data page of a passport, a driver's license and a payment card.

[0032] Such card-shaped data carriers usually have a large number of security elements. The method can produce additional fluorescent security features with a high design diversity. In particular, in the final processing, the data carriers that are manufactured and personalized can be equipped with fluorescent effects accordingly. This final processing can also be carried out separately from the actual production, for example at the customer's site.

[0033] According to other embodiments, the surface is illuminated in sections according to a pattern or visual object in order to generate a corresponding fluorescent visual object.

[0034] For this purpose, the laser can, for example, "re-trace" or scan the corresponding visual object with corresponding laser parameters. Such a visual object can, for example, be planned in a computer (for example according to a photo or other template) optionally and not limited to automation, and the laser can be controlled accordingly.

[0035] According to other embodiments, the irradiated section is selected during the irradiation in such a way that the resulting fluorescent property serves as a security feature.

[0036] For example, the illuminated area can be designed according to a photo of the holder or a photo of another suitable visual object. It is also conceivable to design the text accordingly.

[0037] According to further embodiments, the method also comprises removing smoke marks from the surface after the irradiation.

[0038] The smoke marks can be removed, for example, by rubbing, grinding, polishing or any other suitable method. As a result, the printed fluorescence (i.e., the printed visual object, for example) is only visible under the corresponding light for exciting the fluorescence, but not without such excitation. Experiments have shown that the printed / generated fluorescence properties remain unchanged even after the smoke marks have been removed.

[0039] According to other embodiments, the material includes at least one of the following materials: opaque and / or transparent polycarbonate (PC), refined material; opaque and / or transparent polyethylene terephthalate (PET), acrylonitrile-butadiene-styrene copolymer (ABS), bio-polycarbonate (PC) and polyvinyl chloride (PVC).

[0040] These materials are some of the most commonly used materials for card-shaped data carriers, such as identity cards, payment cards, etc., and have proven to be the most suitable materials for producing / transmitting fluorescent properties. However, it should be noted that this enumeration is only exemplary and that in principle any suitable material, in particular plastic material, can be used.

[0041] Refined materials are understood here to mean all materials / films which have been optically refined in some way, for example by incorporation (eg extrusion) of optically active particles (eg glitter effects), etc. Such optically active particles do not impair the disclosed method and its effects.

[0042] According to other embodiments, the method further comprises cutting the irradiated region, so that an edge of the cut irradiated region has the fluorescent property.

[0043] For example, a material, in particular a card-shaped material (such as a card-shaped data carrier), can be irradiated with a laser over the entire surface or, for example, can also be irradiated at least partially with a laser only in an edge region (i.e., for example, in a strip-shaped region extending around a predetermined edge of the manufactured card-shaped data carrier). The card body of the card-shaped data carrier can then be cut in such a way that the cut edge is located in the irradiated region. This results in at least partial fluorescence properties of the edge of the material. It is also conceivable that the irradiated region itself is cut with a laser, so that the cutting with the laser (and the associated irradiation of the cut edge) gives the cut edge the fluorescent properties. The irradiated region can thus refer to material that has previously been irradiated in the cut region or to material that has not previously been irradiated, so that the irradiated cut edge has a unique fluorescence and the cut region thus becomes the irradiated region.

[0044] According to other embodiments, the material is designed to be planar. The method also includes placing the material as an insert in a card-shaped data carrier.

[0045] Thus, for example, it is possible to prefabricate planar inserts with corresponding fluorescent properties, which can then be laminated into a card-shaped data carrier. The material can thus be, for example, a single layer made of a corresponding plastic material (such as PC, a refined material (as described above, i.e. containing corresponding fillers / refined pigments), PET, ABS, bio-PC, PVC, etc.), which is treated by the method described in order to be printed with fluorescent properties. The corresponding insert can then be laminated together into a card-shaped data carrier (usually consisting of a plurality of layers laminated together), i.e., for example, it is placed in a corresponding recess in one of the layers (e.g., in a core layer covered only by a transparent layer) and laminated together. The insert is therefore generally smaller than the card-shaped data carrier. In this way, for example, prefabricated fluorescent anti-counterfeiting features or other fluorescent optical effects can be produced, which only need to be laminated together when laminating the card-shaped data carrier.

[0046] According to another aspect, a document is provided, wherein the fluorescent property has been at least partially transferred to the document by means of the above method. For example, such a document may be a card-shaped data carrier, a banknote, an identity card, a passport or any other document. For example, the above method may be used to generate a fluorescent anti-counterfeiting feature in such a document. Here, the method may be performed according to any of the above embodiments.

[0047] In summary, the object of the invention is to reprocess, for example, during the final processing, a card body which has already been manufactured and personalized, using a CO2 laser or a fiber laser, for example but not limited to, in order to introduce in this way a fluorescent effect that is recognizable when irradiated with ultraviolet light into the card. The fluorescent effect can be introduced into the card over a large area, that is, at any position on the front and / or back. It is assumed that in the case of laminated card-shaped data carriers, in particular the two outer film layers are chemically changed by the laser (the inventors are not yet aware of the specific chemical process). The advantage of using a CO laser or a fiber laser to produce the fluorescent effect is that no additional manufacturing steps are required, such as inserting / applying fluorescent pigments in or on the card. In addition, the use of laser technology to produce the fluorescent effect has the advantage of design diversity, because the fluorescent effect can be produced at any position on the front and / or back. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The embodiments are described in more detail below with reference to the accompanying drawings. The drawings are schematic and not drawn to scale. The same reference numerals refer to the same or similar elements. In the drawings:

[0049] Figure 1 The structure of a device with a laser which can be used to carry out the method for producing fluorescent properties is shown exemplarily and highly schematically;

[0050] Figure 2 A flow chart showing a method for producing fluorescent properties in a material;

[0051] Figure 3 An exemplary fluorescent visual object applied to a card-shaped data carrier is shown without UV irradiation (smoky trace) and with UV irradiation (fluorescence), wherein the material comprises a refined pigment (for example an OVI pigment; English: Optical Variable Image, OVI);

[0052] Figure 4 An exemplary fluorescent visual object applied to a card-shaped data carrier is shown during the formation of a stronger smoke mark without UV irradiation (smoky mark) and with UV irradiation (fluorescent mark);

[0053] Figure 5 An exemplary fluorescent visual object applied to a card-shaped data carrier is shown without UV irradiation (smoke trace) and with UV irradiation (fluorescence) during the formation of a weaker smoke trace. DETAILED DESCRIPTION

[0054] The views in the accompanying drawings are schematic and not drawn to scale. In the following description of the drawings, if the same reference numerals are used in different drawings, these reference numerals represent the same or similar elements. However, the same or similar elements may also be represented by different reference numerals.

[0055] Figure 1 A highly schematic diagram of a structure for performing the method 100 disclosed herein is shown (see Figure 2 ). The laser 20 is arranged above the material 10, which is exemplarily in the form of a card-shaped data carrier 10, so that the laser 20 can selectively and segmentally irradiate the material 10, that is, the laser beam 21 can be guided on the material 10 in a position-variable manner. For example, the laser 10 can be mounted on a two-dimensional guiding device (not shown) or can include a corresponding adjustable lens system (not shown) in order to change the incident point of the laser beam 21 on the material 10. In addition, the laser 20 and any possible guiding device or lens system or any other suitable mechanism or electronic device for changing the incident point of the laser beam 21 on the surface 11 of the material 10 can be connected to a control device (not shown), which controls the corresponding components accordingly. For example, the control device can control laser parameters (such as power, pulse duration, wavelength, etc.), laser position (including the incident angle of the laser beam 21 on the surface 11 of the material 10) and the movement speed of the laser beam 21 in order to perform Figure 2 method.

[0056] refer to Figure 2 and continue to refer to the flowchart in Figure 1 , a method 100 for producing fluorescent properties in a material 10 is now described. The method starts with providing 110 the material 10 and providing 120 the laser 20. Steps 110 and 120 may be performed in parallel.

[0057] For example, the material 10 may be a card-shaped material 10, such as a card-shaped data carrier 10, which may be designed as an identity document, a payment card or any other card-shaped data carrier 10. In the following, the method 100 will be described with reference to a card-shaped data carrier 10. However, it should be appreciated that the method may in principle be performed on any suitable material 10 or object.

[0058] For example, the card-shaped data carrier 10 can be provided 110 automatically on a conveyor belt. For example, a pouring device can pour the material to be irradiated on the conveyor belt. The conveyor belt can then continue to run, for example at certain time intervals, so that the card-shaped data carrier 10 is arranged (step 130) in the beam path of the laser 20, i.e., in the laser beam 21 (see Figure 1) below the area that can be irradiated, thereby moving the corresponding card-shaped data carrier 10 to be irradiated below the laser 20 or below the area that can be irradiated by the laser 20. However, this is only an example, and the card-shaped data carrier 10 can be provided in any suitable manner.

[0059] The method 100 may be performed in a stand-alone device, or the device used to perform the method (ie, at least the laser 20) may be part of a larger manufacturing facility.

[0060] The laser 20 is preferably a CO2 laser 20 or a fiber laser 20. These laser types have proven to be particularly effective in producing fluorescent properties and have been described above.

[0061] The method 100 continues with at least sectionally irradiating 140 the surface 11 of the card-shaped data carrier 10 in this example. For example, the laser 20 can irradiate a certain pattern or visual object (such as Figures 3 to 5 ). However, it is also possible to cut out, for example, a portion of a larger material with the laser itself, whereby the edge of the cut material becomes fluorescent. It is assumed that by irradiating the surface 11 of the card-shaped data carrier 10 (or the material 10 in general) (or also the cut edge, i.e. by irradiating the material with the laser in general), the material 10 is chemically changed in such a way that it has fluorescent properties. In particular, molecules with conjugated double bonds show fluorescence, since the electrons move through a plurality of atoms here and are therefore easily excited. It is therefore assumed that this change of the material 10 occurs when irradiated with the laser under the right conditions.

[0062] The card-shaped data carrier 10 is usually laminated from a multilayer structure. In such a laminated layer structure, it is particularly assumed that the laser 20 chemically changes the two outer layers in such a way that the fluorescent properties of these layers are formed.

[0063] In particular, CO2 lasers and fiber lasers have proven to be particularly effective in producing fluorescence properties. However, other laser types are also conceivable in principle.

[0064] The irradiation 140 is continued until a visible smoke mark 12 is formed (see Figure 35 ), the smoke marks appear, for example, as a yellowish discoloration. It has been shown that the more pronounced the smoke marks 12 are, the stronger the fluorescent properties are. The duration of the irradiation and the parameters of the laser also depend, in particular, on the material being irradiated. In particular, the following materials have been shown to be particularly suitable for producing fluorescent properties: opaque and / or transparent polycarbonate (PC), refined materials (e.g. containing refined pigments such as OVI pigments), opaque and / or transparent polyethylene terephthalate (PET), acrylonitrile-butadiene-styrene copolymers (ABS), biopolycarbonate (PC) and polyvinyl chloride (PVC). In principle, however, other materials can also be considered for the method disclosed herein.

[0065] The laser parameters (power, pulse frequency, wavelength, pulse energy, etc.) and in particular the necessary irradiation duration of course depend on the material to be irradiated. However, the following parameters have proven to be particularly effective:

[0066] • CO2 laser: Power: 60W to 80W; Wavelength: 10.6µm; Repetition rate does not exceed 100kHz when in pulsed operation.

[0067] • Fiber laser: Power 20W to 30W; Wavelength: 1064nm; Repetition rate: Operation at full power at 25kHz to 600kHz, and operation in pulsed operation with linearly reduced power at 1kHz to 25kHz; Pulse energy: 0.8mJ at a repetition rate of 25kHz.

[0068] However, these parameters are only exemplary, and other parameters may also prove to be effective. In particular, the laser does not have to be operated in a pulsed mode. In general, the energy introduced is important, which is determined in particular by the laser power, the irradiation duration and the pulse frequency (in pulse operation, because the pulse frequency also affects the effective irradiation duration). The irradiation duration for the corresponding material can be controlled in particular by the extent of the smoke mark 12. It must be ensured here that the first smoke mark 12 is displayed, but the smoke mark cannot be formed too strongly or too weakly, because in the case of weaker formation, the fluorescent properties are only insufficiently formed (see Figure 5), and in the case of too strong formation, the material 10 may be damaged. However, the smoke mark does not have to be visible to the naked eye, but can also be confirmed in other ways, for example using auxiliary devices such as microscopes. Therefore, the smoke mark 12 illustrates a visually perceptible measure of the introduced laser energy with respect to the corresponding material.

[0069] Optionally, the at least sectioned illumination 140 can include an illumination 141 at a first angle and then an illumination 142 at a second angle, in order to produce a direction-dependent fluorescence characteristic. For example, a first visual object (such as a text and / or graphic visual object) can be illuminated at a first angle and a second visual object can be illuminated at a second angle. By means of illumination at a certain angle, a direction-dependent fluorescence is produced, so that, for example, a fluorescent tilted image can be produced, which is particularly suitable as a security feature. It is also conceivable to irradiate at more than two angles.

[0070] Optionally, the method 100 may further comprise removing 150 the smoke marks 12 after the irradiation 140. For example, the smoke marks may be ground off, wiped off, polished or removed in other ways. Thus, the irradiated visual object 14 is only visible as fluorescence under ultraviolet light and is no longer visible under daylight.

[0071] Furthermore, the method 100 can optionally include cutting 160 the irradiated region 13. In this case, the irradiated region 13 can be configured in particular such that the cutting edge is also irradiated (in particular by cutting out the irradiated region 13 itself by laser). As a result, fluorescent properties can be achieved in the edge.

[0072] Furthermore, the method 100 can optionally include placing the material 10 (when the material is not a card-shaped data carrier itself) as an insert 170 in a card-shaped data carrier. In such a design, the material 10 is therefore also designed to be planar, but smaller than a card-shaped data carrier. For example, the irradiated material 10 can include only one layer and be smaller than a card-shaped data carrier. The insert thus prepared can, for example, be accommodated in a recess in an inner layer of a card-shaped data carrier before lamination and laminated together.

[0073] Figure 3 An exemplary fluorescent visual object 14 is shown, which can be produced by the method 100 described herein. In this example, the irradiated material also contains a refined pigment (such as an OVI pigment; English: Optical Variable Image, OVI). The refined pigment does not affect the fluorescent properties produced. Here, Figure 3 The left side of the figure shows a "daylight view" 50, i.e. a view without UV excitation light. Here, the smoke marks 12 on the illuminated area 13 are clearly visible. Here, the illuminated area 13 describes the area that forms the visual object 14 and is traversed by the laser 20. Figure 3 The right side of the diagram shows an ultraviolet view 60, i.e. a view of the material treated by the method 100 exposed to ultraviolet excitation light. It can be clearly seen here that in the irradiated areas 13, fluorescent properties are generated in the material 10.

[0074] Figure 4 and Figure 5 It shows that less smoke marks are formed 12 (see Figure 5 ) and the fluorescence characteristics produced when the smoke mark 12 is formed more strongly (see FIG. 4 ). Figure 4 In contrast, in the case of less formation of smoke marks 12 , ie in the case of too short an irradiation time and / or too little irradiation energy (in general too little laser energy introduced into the respective material), the fluorescence properties are formed significantly weaker.

[0075] The method 100 described herein thus provides a possibility to provide a material, such as a card-shaped data carrier 10, with fluorescent properties without the need to introduce additional materials, such as fluorescent color pigments. Instead, the fluorescent effect is inherently printed on the material 10. This allows for a greater variety of designs, especially after the actual production of the material 10, such as a card-shaped data carrier 10, has been completed, and personalization can also be achieved by means of the fluorescent effect.

[0076] It should also be noted that "comprising" or "having" does not exclude any other elements or steps, and "one" does not exclude a plurality. In addition, it should be noted that the features or steps described with reference to one of the above embodiments can also be used in combination with other features or steps of other embodiments in the above embodiments. The reference numerals should not be regarded as a limitation.

[0077] List of Reference Numerals

[0078] 10 (Card-shaped) materials, card-shaped data carriers

[0079] 11 Surface (of material)

[0080] 12 Smoke marks

[0081] 13 Irradiated area

[0082] 14 Fluorescent Visual Objects

[0083] 20 Laser, CO2 laser, fiber laser

[0084] 21 Laser Beam

[0085] 50 Daylight View

[0086] 60 UV Views

[0087] 100 Methods

[0088] 110 Provide materials

[0089] 120 Lasers provided

[0090] 130 Arranging the material in the beam path of the laser

[0091] 140 Irradiated Materials

[0092] 141 Irradiation at the first angle

[0093] 142 Illuminating at a Second Angle

[0094] 150 Remove smoke marks

[0095] 160 Cutting the irradiated area

[0096] 170 Placing material as an insert in a card-shaped data carrier

Claims

1. A method (100) for producing at least partially fluorescent properties in a material (10), the method (100) comprising: providing (110) material (10); Providing (120) a laser (20); placing (130) a material (10) in a beam path of a laser (20) so that the laser (20) can selectively and segmentally illuminate the material; and irradiating (140) the surface (11) of the material (10) at least partially with a laser (20); In this case, the surface (11) of the material (10) is irradiated (140) at least partially with a laser (20) for such a long time that a visible smoke mark (12) is formed on the irradiated area (13) of the surface (11) of the material (10), thereby generating fluorescent properties in the irradiated area (13).

2. The method (100) according to claim 1, wherein: The laser (20) is one of a CO2 laser (20) and a fiber laser (20).

3. The method (200) according to claim 2, wherein: When the laser (20) is a CO2 laser (20), the CO2 laser (20) is operated at a power between 60 W and 100 W and a wavelength of 10.6 μm, and Wherein, when the laser (20) is a fiber laser (20), the fiber laser (20) is operated at a power between 20 W and 30 W and a wavelength of 1064 nm.

4. The method (100) according to any of the preceding claims, wherein: A surface (11) of the material (10) is irradiated (140) with a pulsed laser (20).

5. The method (100) according to any of the preceding claims, wherein: The irradiation (140) of the surface (11) of the material (10) comprises at least irradiation (141) of the surface (11) at a first angle to produce a first fluorescence and irradiation (142) of the surface (11) at a second angle to produce a second fluorescence, so as to produce direction-dependent fluorescence characteristics, so that the corresponding fluorescence is only visible at the corresponding angle.

6. The method (100) according to any of the preceding claims, wherein: The material (10) is a card-shaped material (10).

7. The method (100) according to claim 6, wherein: The card-shaped material (10) has a layer structure including a plurality of layers laminated together.

8. The method (100) according to claim 6 or 7, wherein: The card-shaped material (10) is a card-shaped data carrier (10).

9. The method (100) according to claim 8, wherein: The card-shaped data carrier (10) is one of an identity card, a data page of a passport, a driver's license and a payment card.

10. The method (100) according to any of the preceding claims, wherein: The surface (11) is illuminated (140) sectionally according to a pattern or visual object in order to produce a corresponding fluorescent visual object (14).

11. The method (100) according to any of the preceding claims, wherein: During the irradiation (140), the illuminated section (13) is selected such that the resulting fluorescence property serves as a security feature.

12. The method (100) as claimed in claim 1, further comprising removing (150) smoke marks (12) from the surface (11) after the irradiation (140).

13. The method (100) according to any of the preceding claims, wherein: The material (10) comprises at least one of the following materials: Opaque and / or transparent polycarbonate, PC; Refined materials; Opaque and / or transparent polyethylene terephthalate, PET; Acrylonitrile butadiene styrene copolymer, ABS; Bio-polycarbonate, PC; and Polyvinyl chloride, PVC.

14. The method (100) as claimed in claim 1, further comprising cutting (160) the irradiated region (13), so that an edge of the cut irradiated region has the fluorescent property.

15. The method (100) according to any of the preceding claims, wherein: The material (10) is designed to be planar; and Therein, the method (100) further comprises placing (170) the material (10) as an insert in a card-shaped data carrier (10).

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