EP3513986B1 - Print sample with conversion material for accurate laser beam positioning - Google Patents

Description

The invention relates to a system for individualization or personalization of an object by means of a laser, comprising at least one object to be marked, and a device for individualization by means of a laser, with: a laser source for generating a laser beam, a two-coordinate deflection unit for the targeted deflection of the laser beam by different solid angles, a control device for controlling the laser source and the two-coordinate deflection unit, and a table with a target marking plane for receiving the object to be marked by means of a laser beam emitting preferably in the infrared spectral range. The invention also relates to a method for individualizing an object by means of a laser.

It is known from the prior art to mark objects, for example documents produced on a plastic basis, in particular documents of value and security documents, with a laser. Documents produced on a plastic basis are often assembled from individual foils, which consist of the same or different plastics, to form a document body. Here, some or all of the foils are designed in such a way that they comprise pigments which are imperceptible to the human observer or at least do not enter the eye and which promote the absorption of laser radiation. The energy absorbed during the absorption of the laser radiation is used to make the plastic material of the appropriately prepared film, ie the layer formed by this film to change in the document. In particular, chemical compounds of the polymers from which the plastic material is formed are broken and carbonization is brought about. This leads to a blackening of the, for example, originally transparent plastic material. Alternatively, it is possible to bring about other changes in color or structural changes through the laser irradiation.

In the case of laser marking of, for example, plastic-based objects, it is possible to control the degree of blackening of the plastic by controlling a pulse energy of the individual laser pulses. This can be used, for example, to generate gray levels for laser marking. Each pixel is advantageously generated by the interaction of a single laser pulse with the material of the document. The laser beam generated by the laser is thus moved over the object via a beam guiding device, so that the individual pulses in the laser beam mark individual image points on the object or in the interior of the object. Continuous vector-like marking is also possible.

A point is a laterally limited area which is preferably designed geometrically as a rectangle or circle or ellipse and preferably has a diameter of at least 10 μm.

For example disclosed DE 101 15 949 A1 an invisible laser marking as a security feature for plastic cards. The security feature is written into a marking layer of the plastic card with a laser in the NIR range. A contained luminescent dye is changed in such a way that the emission spectrum changes in terms of its intensity and wavelength.

Also disclosed WO 03/081522 A2 a device and a method for the identification and authentication of an object with the aid of coded security information which is applied to the object with luminescent dyes. These are excited with the aid of a light source and show a luminescence which is received by a detector device

Neither WO 03/081522 A2 still DE 101 15 949 A1 discloses that the control device is set up to control the laser source in such a way that at least one laser beam can be generated with a first scan intensity and a second marking intensity, the scanning intensity being less than the marking intensity.

In order to achieve a high quality marking of the documents, an adjustment of the device is necessary. For this purpose, a reference object, for example a reference card, on which a specific reference pattern is applied, is usually used. This Reference patterns (usually print marks such as crosses, a color-coded QR code or a color-coded grid) can then be captured by an optical camera in order to then adjust the camera first. In particular, curvatures and imaging errors such as cushions, barrels, transparency are taken into account by means of correction parameters. Subsequently, the reference object or another object is marked with a predetermined test pattern, which in turn is recorded with the previously adjusted camera, camera-specifically corrected and the positioning of the two coordinate deflection units is corrected via a target / actual comparison. Overall, coordinating or setting the coordinates of the device to the coordinate system of the map is difficult and time-consuming, and there is a need to simplify this.

Before each step of individualization of each object by means of a laser, certain print marks can also be read in with the high-resolution camera in order to determine the position of the object precisely. This position determination is also subject to errors if the camera is defective. Furthermore, such a step is expensive.

It is therefore an object of the invention to achieve a simple coordination of the coordinate system of the device and the coordinate system of the object. In particular, recognition of a region of the object into which the marking is to be made is to be made easier.

The invention achieves the object in a first aspect by means of a system of the type mentioned at the outset, the object to be marked having a reference marking with conversion material. The control device of the device is also set up to control the laser source in such a way that at least one laser beam can be generated with a first scan intensity and a second marking intensity, the scanning intensity being less than the marking intensity and, when an object is irradiated with the scanning intensity, no marking of the object takes place, wherein the device has a light-sensitive receiver which is provided for detecting luminescent radiation emitted by the object, and wherein the light-sensitive receiver is connected to the control device in order to assign a direction of the laser beam to a direction of reception of luminescent radiation. The reference marking is preferably formed from conversion material.

The object to be marked is preferably a blank card for, for example, chip cards or other ID or identity documents, such as preferably value and security documents, in particular identity card, driver's license, passport, credit card, etc.

The invention is based on the idea that complex passive image capture by means of the camera can be avoided by adjusting the device with the aid of an object coated with conversion material (fluorescent), for example a chip card, in which the fluorescent used is activated with a preferably an IR laser beam emits an emission in the preferably visible spectral range, which can be detected by means of a light-sensitive receiver of the device. With the aid of the described arrangement, the controlled direction of the laser beam and the received luminescence radiation can be assigned directly, so that a target / actual comparison can be made for the control device and in particular the two-coordinate deflection unit. A comparison between the position of the reference mark and the controlled direction of the laser beam can be made. However, it should be understood that an IR laser does not necessarily have to be used in the context of the invention. More important is stealing with two different intensities. It is also not absolutely necessary for the luminescence radiation (converted radiation) to be in the visible spectral range, even if this is preferred. It is more important that the spectral range of the luminescence radiation deviates from that of the laser, so that the luminescence radiation can be distinguished from reflected radiation.

In this case, the use of a camera for the optical detection of a print mark or the like applied in contrasting colors is not necessary. This also avoids those errors that exist due to an optical distortion of the camera. Since no camera is required, there is also no need to adjust the camera. Overall, a direct assignment of the reference marking to the device is thus achieved, since the laser beam is used to detect the reference marking, and no additional device, such as an optical camera with corresponding image processing software.

The scanning intensity and the marking intensity preferably differ in the energy input. While the scanning intensity of the laser beam is selected so that no marking takes place, when the object is irradiated with the marking intensity, marking, that is to say carbonization of certain particles, takes place. The scanning intensity and the marking intensity of the laser beam can differ in wavelength. For example, a wavelength can be selected for the emission of the laser beam with the scan intensity which is particularly suitable for exciting the conversion material such as the anti-Stokes phosphor or up-converter material that is used in the object. This wavelength depends in particular on which conversion material is used for the reference marking of the object.

According to a first preferred embodiment, the control device is also set up to introduce a predetermined marking into the object, the marking being positioned in the target marking plane as a function of the received luminescence radiation. After luminescence radiation has been received, the position of the reference marking relative to the laser source or the two-coordinate deflection unit is known, and the predetermined marking can be introduced. The control device then preferably switches the laser source so that instead of Laser beam with scanning intensity a laser beam with marking intensity is emitted. A predetermined marking can in particular comprise a lettering or an image, such as, in particular, a personalized lettering, the name of the cardholder, a picture of the cardholder or the like.

The control device is preferably also set up to determine a unique position of the object based on a first luminescence radiation received by the receiver in a first direction of the light beam and a second luminescence radiation received by the receiver in a second direction of the laser beam different from the first direction. The determined position of the object is preferably stored in the control device. In this way, without requiring an additional optical check by a camera, a clear position of the object to be marked relative to the laser, in particular to the two-coordinate deflection unit, can be determined and the marking can be introduced very precisely into the object to be marked.

The object preferably has a predetermined marking area in which a marking is to be introduced, the reference marking identifying the marking area. In this variant, it can be sufficient to determine a clear position for the marking area. It is not absolutely necessary to determine the position of the object. The reference marking preferably identifies the position of the marking area in the object. The reference marking preferably identifies a size of the marking area. In this way, the marking can be introduced automatically, namely exclusively as a function of the reference marking.

In a preferred development, the marking area has a pigment grid. The pigment grid comprises pigments that can be carbonized by means of the laser beam. It can be provided that the object is completely interspersed with such pigments, it being preferred that only the marking area has these pigments. The pigment grid preferably has at least pigments of a first color and pigments of a second color different from the first color. In this way, an at least two-colored marking can be introduced by carbonizing pigments of one or the other color. For example, the pigment grid is designed as a CMY grid with pigments in cyan, magenta and yellow. In this way, a completely colored individualization can be achieved by means of a laser. Since the marking area is indicated by the reference marking and is not determined indirectly via an optical camera, a much more precise positioning is possible of the laser beam, which enables or significantly simplifies color customization by means of a laser.

The reference marking preferably identifies one or more grid points of the pigment grid. This can be done, for example, in that the reference marking marks the corners of the pigment grid, for example by means of crosses, as are known from conventional printing marks. A distance between the reference marking and the pigment grid is preferably small in order to also keep tolerances and thus deviations in the emission direction of the laser beam small. This allows the accuracy to be increased further.

In one variant, the marking area has one or more sub-areas, and the reference marking identifies the one or more sub-areas. This allows the reference marking to be assigned directly to the sub-areas in order to further increase the accuracy.

In a preferred development it is provided that conversion material is added to the pigments of the first color. This can be preferred both in the case of monochrome pigment grids, which only have pigments of the first color, and in multi-colored pigment grids. This makes it possible to identify each individual pixel of the pigment grid individually and thus to achieve a very precise assignment. As soon as luminescence radiation is received, the direction of the laser beam no longer has to be changed, but only the intensity has to be increased to the marking intensity.

In a second aspect of the invention, the aforementioned object is achieved by a method for individualizing an object by means of a laser, preferably using a system according to one of the preferred embodiments described above of a system according to the first aspect of the invention, with the steps of: arranging the to marking object with a reference marking with conversion material on a table of a device for individualization by means of a laser; Generating a laser beam with a scanning intensity at which the object is not marked; Scanning the object with the laser beam at the scanning intensity by controlling the direction of the laser beam; Receiving luminescent radiation; Assigning the direction of the laser beam for receiving the luminescent radiation; Generate a laser beam with a Marking intensity; and as a function of the received luminescence radiation, introducing a predetermined marking into the object by means of the laser beam with the marking intensity.

It should be understood that the device according to the first aspect of the invention and the method according to the second aspect of the invention have the same and similar sub-aspects as are set out in particular in the independent claims. In this respect, reference is made in full to the device according to the first aspect of the invention for advantages and further preferred features.

In a further preferred embodiment it is preferably provided that the object to be marked has a marking area with a pigment grid, the pigment grid having at least pigments of a first color and pigments of a second color different from the first color, the method comprising the step of: optional irradiation either a pigment of the first or the second color at a raster point of the dot rater in order to obtain a colored marking. When the pigment of one color is blackened out, the color of the other pigment becomes more prominent, so that a colored mark can be seen. The pigments of the first and second colors can, for example, be provided in different target marking planes, so that either one or the other pigment is blackened out by appropriate focusing of the laser beam.

Also disclosed is an object for use in a system according to one of the above-described preferred embodiments of a system according to the first aspect of the invention and / or a method according to one of the preferred embodiments of a method according to the second aspect of the invention, the object being a Has base body and a reference mark with conversion material. The object and the system according to the first aspect of the invention and the method according to the second aspect of the invention have the same and similar sub-aspects as are set out in particular in the dependent claims. In this respect, reference is made in full to the above description, in particular with regard to the object that is used in the system according to the first aspect of the invention.

The object is preferably designed as a card blank. The reference marking preferably represents a coordinate system of the object.

In a preferred embodiment, the reference marking is selected from a group comprising: raster, barcode, QR code, one or more polygons, several lines arranged at an angle to one another, several points. Combinations of these are also conceivable and preferred. For example, on the one hand a QR code can be provided that represents certain information, but also a square that borders an area to be marked. Crosses, as they are known as print marks and are usually provided on conventional cards, are also preferred, in order to be recorded by means of an optical camera.

It is also preferred that the width of the reference marking corresponds to one pixel. That is, one line of the grid, one line of the polygon or the like corresponds to one pixel. This simplifies an assignment of received luminescence radiation to a controlled direction of the laser beam, since a defined width and thus also a defined distance between individual image points is specified. It has been found, for example, that a width of a pixel of less than 100 μm, preferably less than 50 μm, approximately in the range of 50 μm is preferred, since both manufacturing tolerances can be maintained and sufficient light intensity with appropriate excitation with the laser beam with the Scan intensity can be emitted.

The conversion material preferably has IR-excitable anti-Stokes phosphors or up-converter materials that emit in the visible spectral range. Such anti-Stokes phosphors or up-converter consist usually of inorganic basic mesh materials in particular by incorporating the Aktivatorkombinationen Yb ³⁺ -He ^3+, Yb ³⁺ -Tm ³⁺ and Yb ^{3+ 3+} in -Ho They are able to transform IR radiation into the visible spectral range via multi-stage excitation processes. When using Yb ³⁺ -Er ³⁺ - and Yb ³⁺ -Ho ³⁺ -activator / coactivator combinations, depending on the type of basic lattice used, mostly green or red-emitting anti-Stokes phosphors are obtained, while Yb ^{3 +} -Tm ³⁺ - doped materials mostly luminesce in blue. Oxidic inorganic compounds ( _{e.g. Y 2} O ₃ , ZrO ₂ , La ₂ MoO ₆ , LaNbO ₄ and LiYSiO ₄ ), oxyhalides (e.g. YOCI, LaOCI, LaOBr, YOF, LaOF), oxysulfides (Y ₂ O ₂ S , La ₂ O ₂ S, Gd ₂ O ₂ S, Lu ₂ O ₂ S) or fluorides (YF ₃ , LaF ₃ , LiYF ₄ , NaYF ₄ , NaLaF ₄ , BaYF ₅ ) are used.

The pigments of the conversion material are particularly preferably selected so that they are capable of offset printing. The pigments preferably have a diameter d90 <5.0 μm. Overall, a pigment loading of about 5 to 15% is preferred in order to achieve sufficient upconversion luminescence.

In addition to the offset printing process, the letterset or flexographic printing processes customary for security documents in the form of smart cards can also be used and included, both with oxidatively drying inks and UV-curing inks.

If two or more nominal marking planes in which different pigment colors are provided are used in the object, different conversion materials can also be assigned to these nominal marking planes. For example, a Yb ³⁺ -Er ³⁺ activator / coactivator combination is arranged in a first level, while a Yb ³⁺ -Tm ^{3 +} -doped material is used in a second level. In this way, depending on the reception of the color of the luminescence radiation, it can be determined in which focal plane the laser beam with the scan intensity caused an excitation. In this way it can be ensured that the focus of the laser beam lies in the correct target marking plane, and thus the pigment of the correct color is carbonized.

Embodiments of the invention will now be described below with reference to the drawings. These are not necessarily intended to represent the embodiments to scale; rather, the drawings, where useful for explanation, are in schematic and / or slightly distorted form. With regard to additions to the teachings that can be seen directly from the drawings, reference is made to the relevant prior art. It must be taken into account that various modifications and changes relating to the shape and detail of an embodiment can be made without deviating from the general idea of the invention. The features of the invention disclosed in the description, in the drawings and in the claims can be essential for the development of the invention both individually and in any combination. In addition, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or the detail of the preferred embodiments shown and described below or limited to an object which would be restricted in comparison to the object claimed in the claims. In the case of the specified measurement ranges, values lying within the stated limits should also be disclosed as limit values and be able to be used and claimed as required. For the sake of simplicity, the same reference symbols are used below for identical or similar parts or parts with an identical or similar function.

Figur 1

eine schematische Ansicht eines Systems zur Individualisierung eines zu markierenden Objekts mittels Laser;

Figur 2

ein zu markierendes Objekt in einem ersten Ausführungsbeispiel; und

Figur 3

ein zu markierendes Objekt in einem zweiten Ausführungsbeispiel.

Further advantages, features and details of the invention emerge from the following description of the preferred embodiments and with reference to the drawings; these show in:

Figure 1

a schematic view of a system for individualizing an object to be marked by means of a laser;

Figure 2

an object to be marked in a first embodiment; and

Figure 3

an object to be marked in a second embodiment.

A system 100 for individualizing an object 14 by means of a laser has a device 1 and an object 14 to be marked. The object 14 to be marked is marked by means of the device 1.

The device 1 has a laser source 2 for generating a laser beam 4. Devices 1 of this type are generally used to laser mark objects, such as, in particular, cards, for example credit cards, identity cards and the like, by focusing the laser beam 4 in order to carbonize certain particles which are accommodated in a card body. A distinction is made in particular between conventional individualization by means of laser, in which only pigments of a single color are used, so that a monochrome marking is carried out, and colored individualization by means of laser, in which multi-colored inscription or marking of the object is also possible. A variant of the colored individualization by means of laser uses a pre-introduced matrix of different colored pigments, namely in particular according to the CMYK color model, in order to then carbonize one, two or all three color pigments (cyan, magenta, yellow) by means of the laser beam 4 in order to prevent the others To stand out. The device 1 disclosed herein is particularly suitable for colored individualization by means of a laser.

For this purpose, provision is preferably made for one of the three colors, for example “magenta”, to be provided with anti-Stokes phosphors. During the scanning process described above, the position of all "magenta points" can be determined. Since "cyan dots" and "yellow dots" are preferably introduced at a fixed distance and angle with respect to "magenta dots", in addition to the direct determination of the position of the "magenta dots", an indirect position determination of the "cyan dots" is also possible. "or" yellow points "possible.

An object 14 to be marked is arranged in the device 1 on a table 10. A target marking plane 12 runs through the object 14, since the particles to be carbonized are provided in the interior of the object 14. In one embodiment, the object 14 to be marked can be a card blank of a chip card. The system 100 can have a magazine for receiving and providing a large number of identical or pre-individualized card blanks, which are then arranged on the table 10 via a specific feed mechanism.

In order to guide the laser beam 4 over the object 14 to be marked, the device 1 has a two-coordinate deflection unit 6 which, for example, consists of two adjustable mirrors. The mirrors can then be rotated on two mutually perpendicular axes so that the laser beam 4 can be guided over the entire target marking plane 12.

The laser source 2 and the two-coordinate deflection unit 6 are controlled by means of a control device 8 on which, in particular, a program can be executed that causes the control device 8 to send control signals to the two-coordinate deflection unit 6 in order to guide the laser beam 4 accordingly in the target marking plane 12 in order to to achieve a desired marking of the object 14. For this purpose, the control device 8 can have known components such as a processor, a memory and one or more interfaces for communication and / or data transmission.

In order to determine the position of the object 14 to be marked and thus the exact position at which a marking is to be made in such a device 1, i.e. in particular to determine the exact position of the pigment grid so that the laser beam 4 is actually aimed at individual pigments and no incorrect marking is carried out, a high-resolution camera was usually used in the prior art to observe the target marking plane 12 and the object 14 to be marked. The camera was used to record certain print marks and thus to determine the position of the pigments.

Such a camera must be adjusted in order to achieve sufficient precision. For this purpose, special cards with reference markings that have already been made can be used. After completing an adjustment of the camera, a test marking was then introduced into a test object by means of the laser source 2 and checked with the camera. A target / actual comparison was carried out and based on this target / actual comparison then the control device 8, the laser source 2 and / or the two-coordinate deflection unit 6 are adjusted in order to achieve correct marking of the object 14.

Such an adjustment comprises a plurality of steps on the one hand, and a high-resolution camera is required on the other hand. Both are undesirable. Even if the target / actual comparison of the introduced test markings has been successfully completed, there may still be other sources of error in the camera, so that the result of the individualization by means of laser is not optimal despite the adjustment.

In contrast to this, it is proposed by the present exemplary embodiment to use an object 14 to be marked, which has a reference marking 17 with, preferably made of, conversion material and to equip the device 1 with a light-sensitive receiver 18 instead of the high-resolution camera, which is capable of detecting from to marking object 14 emitted luminescence radiation 20 is provided. The light-sensitive receiver 18 is connected to the control device 8. The control device 8 is designed to assign a controlled direction of the laser beam 4 to receive luminescence radiation 20. In this way it can be recognized which section of the object 14 the laser beam 4 is directed, and where the marking area begins or ends, or where certain pigments are introduced. The reference marking 17 on the object 14 to be marked is known and it is known in which controlled direction of the laser beam 4 luminescence radiation 20 would have to be received. A high-resolution camera is not required for this, but a simple light-sensitive receiver 18 is sufficient. In this exemplary embodiment, the light-sensitive receiver 18 is designed in particular as a photodiode 19.

In this exemplary embodiment, the laser source 2 is designed to emit a laser beam 4 with a scan intensity and with a marking intensity. When the object 14 to be marked is irradiated with the scan intensity, no marking takes place, that is to say no carbonization of pigments. However, the scanning intensity of the laser beam 4 is high enough to excite the conversion material which is provided in the object 14 for the reference marking 17, so that luminescence radiation 20 is emitted. For this purpose, the laser beam 4 preferably has a wavelength in the infrared (IR) range. In contrast to this, the marking intensity of the laser beam 4 is so high that individual pigments can be carbonized in the object 14. In particular, given a marking intensity, it is also possible to carbonize pigments of the conversion material so that the conversion property is lost.

The laser source 2 is preferably designed as an infrared laser source and preferably emits laser beams in the near-infrared range, such as around 1000 nm wavelength (e.g. 980 nm and / or 1190 nm wavelength), which then causes an emission of luminescence radiation with approximately 500 nm radiation. It is also conceivable that the laser source 2 is set up to emit a different wavelength when emitting a laser beam 4 with the scan intensity than when emitting a laser beam 4 with marking intensity. The wavelength of the laser beam 4 should be matched to the conversion material used (preferably anti-Stokes phosphor or up-converter), or vice versa.

How to continue from Figure 1 results, an optical system 24 is used in the beam path of the laser beam 4. In this exemplary embodiment, the optics 24 consists of a first lens 32, which is designed as a tube lens, and a second lens 34, which is designed as an objective or front lens. The laser beam 4 is focused on the target marking plane 12 by means of the two lenses 32, 34 in order to introduce a marking 22 there.

Furthermore, a beam splitter 26 is arranged in the beam path, which is used to couple the luminescence radiation 20 emitted by the object to be marked out of the beam path so that it is guided to the light-sensitive receiver 18. The beam splitter 26 can be designed as known in the prior art, for example as a partially transparent mirror. In certain exemplary embodiments it can be provided that the beam splitter 26 is provided with a filter.

In this exemplary embodiment, a third lens 36, which in turn is designed as a tube lens, as well as a filter 28 and a perforated diaphragm 38 are arranged in the beam path of the luminescence radiation 20. The third lens 36 is again used for focusing, while the filter 28 and the perforated diaphragm 38 are used to filter out stray light. More precisely, the filter 28 in this exemplary embodiment is designed as a notch filter in order to only allow light with the wavelength of the luminescent radiation (for example around 500 nm) to pass through. For example, reflected radiation from the object 14 is filtered out. In the beam path that runs from the object 14 to the light-sensitive receiver 18, both luminescence radiation 20 and reflected radiation that is not luminescence radiation are coupled. It is important to filter out the radiation that is not luminescent radiation so that a light pulse is not erroneously received at the light-sensitive receiver 18. The filter 28 is used for this purpose. Further filters can be provided, such as, for example, blocking filters for the wavelength of the laser beam 4 or the like.

The perforated diaphragm 38 then serves to filter out non-focused radiation, that is to say likewise scattered radiation that is reflected, for example, from a surface 40 of the object 14.

In this way, the beam path of the luminescence radiation 20 and the laser beam 4 is identical in sections and in any case runs completely through the optics 24, which are provided for the laser beam 4. In this way, imaging errors that are caused by the optics 24 can remain unconsidered or are automatically taken into account and do not have to be taken into account separately. The luminescence radiation 20, which is used to determine the position of the laser beam 4 relative to the object 14 to be marked, also passes through the optics 24 and thus experiences the same deflections as the laser beam 4 passing through the optics 24.

The Figures 2 and 3 show two different exemplary embodiments of an object 14 to be marked. Both objects 14 are each designed as a card blank, in particular for a credit card, chip card, passport document or the like, and have a base body 30. An area in which a marking 22 is to be introduced for the individualization of the object 14 to be marked is referred to as the marking area 15. In the marking area 15, pigments of at least one color are provided in a pigment grid, which are then selectively carbonized by means of the laser beam 4 in order to introduce the marking 22. In both embodiments of the Figures 2 and 3 an asterisk is shown as a marker 22 as an example. However, it should be understood that instead of the star, other markings, in particular a name, images, graphics, encrypted codes or the like, can also be introduced.

In both embodiments ( Figs. 2 and 3 ) The in Figure 2 In the illustrated embodiment, a reference marking 17 in the form of a rectangle is introduced with conversion material. The reference mark 17 identifies the marking area 15 in each case. In the first exemplary embodiment ( Fig. 2 ) the marking area is bordered by means of the reference marking 17 designed as a rectangle. This uniquely identifies the marking area 15.

Instead of the rectangle, other markings are also conceivable, such as in particular raster, barcode, QR code, one or more polygons, several lines arranged at an angle to one another, several points. Combinations of these are also conceivable and preferred. For example, on the one hand, a QR code can be provided that specifies Represents information. Crosses, as they are known as print marks and are usually provided on conventional cards, are also preferred, in order to be recorded by means of an optical camera.

The width of a line of the reference marking 17 corresponds to one pixel in this exemplary embodiment. Specifically in this exemplary embodiment, the width is approximately in the range of 50 μm. The conversion material preferably has IR-excitable anti-Stokes phosphors or up-converter materials that emit in the visible spectral range. Such anti-Stokes phosphors or up-converter consist usually of inorganic basic mesh materials in particular by incorporating the Aktivatorkombinationen Yb ³⁺ -He ^3+, Yb ³⁺ -Tm ³⁺ and Yb ^{3+ 3+} in -Ho They are able to transform IR radiation into the visible spectral range via multi-stage excitation processes. When using Yb ³⁺ -Er ³⁺ - and Yb ³⁺ -Ho ³⁺ -activator / coactivator combinations, depending on the type of basic lattice used, mostly green or red-emitting anti-Stokes phosphors are obtained, while Yb ^{3 +} -Tm ³⁺ -doped materials mostly luminesce in blue. Oxidic inorganic compounds ( _{e.g. Y 2} O ₃ , ZrO ₂ , La ₂ MoO ₆ , LaNbO ₄ and LiYSiO ₄ ), oxyhalides (e.g. YOCI, LaOCI, LaOBr, YOF, LaOF), oxysulfides (Y ₂ O ₂ S , La202S, Gd202S, Lu ₂ O ₂ S) or fluorides (YF3, LaF3, LiYF4, NaYF4, NaLaF4, BaYF ₅ ) are used.

The pigments of the conversion material are particularly preferably selected so that they are capable of offset printing. The pigments preferably have a diameter d90 <5.0 μm. Overall, a pigment loading of about 5 to 15% is preferred in order to achieve sufficient upconversion luminescence.

In addition to the offset printing process, the letterset or flexographic printing processes customary for security documents in the form of smart cards can also be used and included, both with oxidatively drying inks and UV-curing inks.

The reference mark 17 according to the second embodiment ( Fig. 3 ) is particularly suitable for colored individualization using a laser or very precise marking. In this exemplary embodiment, the reference marking 17 comprises a grid of pigments of the conversion material. On the one hand, this grid can indicate individual sub-areas of the marking area 15, or it can serve to identify individual pixels. For example, a pigment of the conversion material can be assigned to every tenth image point both in the x and in the y direction. When scanning the object 14 to be marked with the laser beam 4 with the scan intensity, it is then possible a distance in the x and y directions between two detected pulses of luminescence radiation 20 can be determined and this distance divided by 10. From this, the position of the individual pigments in the pigment grid is known, which are to be selectively carbonized. The positioning of the laser beam 4 can be based on the reception of luminescence radiation 20.

In the object 14 to be marked it can be provided that two or more focal planes are provided in which different conversion materials are arranged. For example, a Yb ³⁺ -Er ³⁺ activator / coactivator combination is arranged ^{in a first level, while a Yb 3+} -Tm ^{3 +} -doped material is used in a second level. Thus, depending on the reception of the color of the luminescence radiation 20, it can be determined in which focal plane the laser beam 4 with the scanning intensity has caused an excitation. This is particularly preferred when a colored laser marking is to be made in the object 14, that is to say, for example, when the object 14 to be marked has different colored pigments in different planes, so that in order to carbonize a single pigment, the focal plane and so that the target marking plane 12 of the laser beam 4 must be shifted with scanning intensity. In this way it can be ensured that the focus of the laser beam 4 lies in the correct nominal marking plane 12, and thus the pigment of the correct color is carbonized.

In the present application, a device 1 and a system 100 are proposed overall, in which no high-resolution camera is required in order to detect a position of the object 14 to be marked. Nevertheless, it can be conceivable that a camera is present, in particular to check the correct positioning of an object 14 to be marked, before scanning is started. This camera does not have to be a high-resolution camera, but can be a conventional camera.

Furthermore, it should be understood that there can also be embodiments in which the beam path of the luminescence radiation 20 is not necessarily guided by means of optics. Depending on the brightness of the emitted luminescence radiation 20, it is sufficient that the light-sensitive receiver 18 receives this scattered radiation. For this purpose, a very sensitive light-sensitive receiver 18 may then have to be provided, which is optionally provided with one or more filters. In this way, the device can be constructed even more simply and, in particular, more cost-effectively can be produced, since elements such as, in particular, the beam splitter 26 and the lens 36 can be omitted.

Claims (10)

1. A system (100) for individualization of an object (14) by laser, comprising:

   at least one object (14) to be marked, comprising a reference mark (17) having conversion material, and

   a device (1) for individualization by laser, having:

   a laser source (2) for generating a laser beam (4),

   a two-coordinate deflection device (6) for targeted deflection of the laser beam (4) by different spatial angles,

   a control device (8) for controlling the laser source (2) and the two-coordinate deflection device (6);
   and

   a table (10) having a target marking plane (12) for receiving the object (14) to be marked by the laser beam (4),

   wherein the control device (8) is adapted to control the laser source (2) such that at least one laser beam (4) with a first scanning intensity and a second marking intensity can be generated, wherein the scanning intensity is smaller than the marking intensity and wherein upon irradiation of the object (14) with the scanning intensity no marking of the object (14) takes place,

   wherein the device (1) comprises a light-sensitive detector (18) adapted for detecting luminescence radiation (20) emitted from the object (14) to be marked,

   wherein the light-sensitive detector (18) is connected to the control device (8) for associating a controlled direction of the laser beam (4) to a detection of said luminescence radiation (20).
2. The system according to claim 1, wherein the control device (8) is further adapted to introduce a predetermined mark (22) into the object (14), wherein a positioning of the mark (22) in the target marking plane (12) is performed dependent on the detected luminescence radiation (20).
3. The system according to claim 1 or 2, wherein the control device (8) is adapted to determine an unambiguous position of the object (14) based on a first luminescence radiation (20) detected by the detector (18) at a first direction of the laser beam (4), and a second luminescence radiation (20) detected by the detector (18) at a second direction of the laser beam (4) different from the first direction.
4. The system according to any of the preceding claims, wherein the object (14) comprises a predefined marking area (15), in which a mark (22) is to be introduced, wherein the reference mark (17) identifies the marking area (15).
5. The system according to claim 4, wherein the marking area (15) comprises a pigment grid, the reference mark (17) preferably identifies one or more grid points of the pigment grid.
6. The system according to claim 5, wherein the pigment grid comprises at least pigments of a first color and pigments of a second color different from the first color.
7. The system according to any one of claims 4 to 6, wherein the marking area (15) comprises one or more subareas, and the reference mark (17) identifies the one or more subareas.
8. The system according to any one of claims 4 to 7, wherein a conversion material is added to the pigments of the first color.
9. A method for individualization of an object (14) by laser, in particular using a System according to any one of the preceding claims, comprising the steps:

   - Arranging an object (14) to be marked having a reference mark (17) having conversion material on a table (10) of a device (1) for individualization by laser;

   - Generating a laser beam (4) having a scan intensity at which no marking of the object (14) occurs;

   - Scanning the object (14) with the laser beam (4) having the scan intensity by controlling the direction of the laser beam (4);

   - Detecting luminescence radiation (20);

   - Associating the direction of the laser beam (4) to the detection of said luminescence radiation (20);

   - Generating a laser beam (4) having a marking intensity; and

   - dependent on the detected luminescence radiation (20), introducing a predetermined mark (22) into the object (14) with des laser beam (4) having the marking intensity.
10. The method according to claim 9, wherein the object (4) to be marked comprises a marking area (15) having a pigment grid, wherein the pigment grid comprises at least pigments of a first color und pigments of a second color different from the first color, and wherein the method comprises:

    - selectively irradiating either a pigment of the first or of the second color at a grid point of the grid to obtain a colored mark (22).

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