WO2003026831A2

WO2003026831A2 - Method and device for laser inscription of data carriers, especially the bodies of cards

Info

Publication number: WO2003026831A2
Application number: PCT/DE2002/003627
Authority: WO
Inventors: Dirk Fischer; Michael Hennemeyer-Schwenker; Frank Kappe; Andreas Migge; Horst Rahne
Original assignee: Orga Kartensysteme Gmbh
Priority date: 2001-09-25
Filing date: 2002-09-25
Publication date: 2003-04-03
Also published as: WO2003026831A3; AU2002339324A1; DE10147037A1

Abstract

The invention relates to a method for the production of an inscription on a data carrier, especially the body of a card(204), using a laser beam (102) which is emitted by a laser (101). In order to produce the inscription surfaces and/or inscription points whose surface is blackened and/or coloured in an essentially uniform manner, the laser beam (102) and or part of the laser beam is homogenized, with regard to the distribution of the power density thereof; in the cross-section of the steel by a homogenizing means, especially a multi-mode glass fibre (104).

Description

Method and device for laser marking of data carriers, in particular card bodies

The invention relates to a method and a device for laser inscription of data carriers, in particular card bodies, according to the preamble of the respective independent patent claim.

Card bodies or data carriers of laser marking systems are provided with image and / or text information in a known manner. Grayscale images are usually generated by point density modulation with constant laser power or laser power modulation with constant point density. With dot density modulation, all pixels have the same blackening; the number of pixels per unit area determines the grayscale. In laser power modulation, the modulation of the power of the laser beam generates pixels with different degrees of blackening and thus gray levels.

Disadvantageously, the pixels and labeling areas produced in a conventional manner do not have a homogeneous or uniform blackening. Rather, the pixels and labeling areas are usually blacker in the middle than at the edge. If such pixels or labeling areas are joined directly, it can be seen with the naked eye that the pixels or labeling areas have been "pieced together". The object of the invention is to provide a method for laser inscription of data carriers, in particular card bodies, which enables the production of 5 inscription surfaces and / or inscription points, the surface of which is largely uniformly blackened and / or colored.

This object is achieved in each case by the measures specified in the independent .0 patent claims. Advantageous refinements of the invention are specified in the dependent claims.

An essential aspect of the invention is that of .5 a conventional laser for laser marking of

Data carriers, such as in particular card bodies for chip and / or identity cards, to modify or homogenize emerging laser radiation by a so-called homogenizing agent. The aim of the modification or homogenization according to the invention is to obtain a laser beam for inscription which has a largely homogeneous or step-like power density distribution along its beam cross section.

According to the invention, this is preferably achieved by using a glass fiber with a plurality of propagation modes, such as in particular a multimode glass fiber. If the laser beam of such a conventional laser is passed through such a glass fiber, it shows from the glass fiber

50 emerging laser beam compared to the laser beam entering the glass fiber a more uniform power density distribution along the cross section of the laser beam. A glass fiber, in particular a multimode glass fiber, is preferably bent and / or twisted and / or

55 arranged in a loop that the power density distribution has a largely step-like power density distribution along the cross section of the laser beam emerging from the glass fiber. In other words, the power density is largely constant along the cross section of the laser beam and largely drops abruptly at the edge.

Advantageously, pixels and / or image areas on data carriers, such as, in particular, the above-mentioned card bodies, can be generated by a laser beam generated according to the invention with a largely homogeneous power density distribution, which have a largely homogeneous or uniform blackening and / or coloring, e.g. B. have a different color than black. The diaphragms according to the invention, which are explained in more detail below, allow individual pixels and / or image areas produced according to the invention to be combined to form text and / or image information. If the pixels and / or image areas produced according to the invention are made correspondingly small, it cannot be seen with the naked eye that the text and / or image information has been combined from several individual labeling elements according to the invention.

The precise assembly of the labeling elements according to the invention can represent, for example, an authenticity feature of a data carrier, such as in particular a chip and / or identification card or the like. Furthermore, the arrangement of labeling elements according to the invention, for. B. two or more labeling elements of different shape and / or size, represent an easily recognizable coding of the data carrier. This arrangement of labeling elements according to the invention can then be scanned using a scanner and the coding can be detected and decoded using suitable software. The decoded Information can then z. B. can be compared with plain text information provided on the data carrier.

For example, the portrait of a person on the disk, e.g. B. an ID card, is shown with a code that represents the name of the person and / or other data of the person, such as the date of birth. After scanning and decoding, this information can then be shown, for example, on a display or the like and compared with information, for example on the data carrier. This makes it possible to check whether the portrait and the identity card belong together.

The invention is explained in more detail below with reference to schematic drawings, which are not necessarily to scale, the same or equivalent parts being provided with the same reference numerals. It shows:

1 shows the basic principle of a laser marking device according to the invention with a multimode glass fiber;

Fig. 2 shows the embodiment of the invention shown in FIG. 1 in which the emerging from the multimode glass fiber

Laser beam is deflected onto the surface of a card body via deflection devices and a lens;

Fig. 3 shows the embodiment of FIG. 2 in the between the output of the multimode glass fiber and the

Deflection devices an imaging optics is provided;

4 shows the letter "A" in a first embodiment, that with the one shown in FIG. 3, laser marking device according to the invention has been generated using a first aperture on the surface of the card body;

5 Fig. 5 shows a second embodiment of the letter "A", with that shown in Fig. 3

Laser marking device has been created using a second aperture on the surface of the card body;

LO

FIG. 6 shows a third embodiment of the letter "A", which was produced with a laser marking device according to FIG. 3 using a third aperture on the surface of the card body;

L5

FIG. 7 shows a fourth embodiment of the letter "A" which has been generated with the laser marking device according to FIG. 3 and a fourth aperture on the card body;

> 0

Fig. 8 is a portrait, which was created by means of the laser marking device shown in Fig. 3 and a fifth aperture on the card body, the portrait consisting of triangles and squares

15 composes;

Fig. 9. an aperture with a square opening, the size of which is adjustable;

FIG. 10 shows a fifth embodiment of the letter “A”, which was produced with the laser marking device according to FIG. 3 and an adjustable diaphragm on the card body; 11 shows a plan view of a first coarse grid with a plurality of uniformly arranged, relatively large, square partial openings, the grid being placed over the letter “A” to be labeled according to FIG. 10 and in the detected large one

Halftone dots are cross-hatched,

Fig. 12 is a plan view of a second central grid with a plurality of the same central square

Partial openings, the grid being placed over the letter “A” to be labeled according to FIG. 10 and in which the detected central grid points are hatched,

13 shows a plan view of a third fine grid with a plurality of relatively small square partial openings, the grid being placed over the letter “A” to be labeled according to FIG. 10 and in which detected small grid points are hatched,

FIG. 14 shows the letter “A” corresponding to FIG. 10, which is generated by the sum of the rasters produced according to FIGS. 11 to 13.

Fig. 1 shows the basic principle of an inventive

Laser marking device 100 in a first

Embodiment. The laser marking device 100 has a conventional laser 101, the laser beam 102 of which is coupled into the input of a multimode glass fiber 104 via an optical system 103. In the diagram on the left of FIG. 1, shown below the laser beam 102, the power density of the laser beam 102 emerging from the laser 101 is a function of the location in the beam cross section specified. The diagram on the left shows a Gaussian power density distribution in the beam cross section of the laser 101, ie the power density of the laser beam 102 has its maximum in the middle of the beam cross section and flattens out towards the edges of the beam cross section. However, the invention is not limited to the use of a laser with a Gaussian power density distribution. If such a conventional laser beam of sufficient power strikes a known card body which is suitable for laser inscription, a pixel is formed which, due to the Gaussian power density distribution, has an increasing blackening from the edge to the center.

To generate an image point and / or an image area on a suitable data carrier, such as in particular a

The card body, which has a largely homogeneous or uniform blackening and / or coloring, is provided according to the invention in the multimode glass fiber 104.

The multimode glass fiber 104 is preferably subjected to a mechanical stress such that it is arranged in a loop and / or twisted and / or bent, for example, such that the laser beam 105 emerging from the multimode glass fiber 104 has a power density distribution in the beam cross section that is largely step-like, as in that right diagram of Fig. 1 shown. The diagram on the right, like the diagram on the left, shows the power density of the laser beam in question as a function of the location in the laser cross section. By using the multimode glass fiber 104 according to the invention, a is preferred

Laser beam 105 is generated, the power density of which is ideally largely constant along its beam cross section and abruptly drops to zero at the edge (step-shaped power density curve). If such a laser beam generated according to the invention strikes the surface of a suitable one Data carrier, such as in particular a known, suitable card body, it generates a pixel or an image surface which has a largely homogeneous or uniform blackening and / or coloring.

5

The optics 103 have one or more optical lenses. Since the multimode optical fiber 104 allows different modes to propagate, ideally a uniform distribution of the optical power of the laser can occur

.0 all modes are reached, as in the diagram on the right of Fig. 1 shown. In order to achieve the most uniform possible distribution of the optical power to the different modes of the glass fiber, it is proposed, as already explained in detail, that the multimode glass fiber be a mechanical one

.5 stress, e.g. B. by bending and / or torsion. The multimode glass fiber is preferably arranged in one or more loops which have a suitable bending radius.

! 0 The multimode glass fiber is preferably a step index glass fiber. A step index glass fiber according to the invention has a refractive index transversely to the longitudinal axis or direction of propagation, which is abruptly increased in the fiber core compared to the surrounding glass fiber.

! 5

Fig. FIG. 2 shows a laser marking device which is compared to that in FIG. 1 shown embodiment around a deflection device 201, in particular a so-called x scanner mirror, and a deflection device 202, in particular

> 0 a so-called y-scanner mirror, and an objective 203 has been added. Objective 203 has one or more optical lenses.

The divergent 55 light beam emerging from the multimode glass fiber 104 is transmitted via the deflection device 201 Deflection device 202 and lens 203 are directed onto a data carrier, such as, in particular, a suitable card body 204. The optical path lengths are preferably dimensioned such that the optical power at the multimode glass fiber end is imaged on the surface of the card body 204. The deflection devices 201 and 202, for example x and y scanner mirrors, are preferably mounted as close as possible behind the glass fiber in order to transmit the entire optical power of the divergent beam path. If the optically transmitting core of the multimode glass fiber has a diameter of 100 μm, for example, and if the blackening and / or coloring on the card body 204 should also have a diameter of 100 μm, then the optical path length between the end of the multimode glass fiber 104 and that is in accordance with the optical imaging law Lens 203 to be selected equal to the distance between lens 203 and the surface of the card body 204.

The embodiment of the invention shown in FIG. 3 differs from that shown in FIG. 2

Embodiment of the invention in that between the end of the multimode glass fiber 104 and the deflection device 201 there is an optical system 301 and a diaphragm or diaphragm device 302 in the beam path. The optics 301 serve to bring the available light output as far as possible through the aperture delimiting the optical system. The aperture device 302 can be an arrangement of one or more apertures, as described in more detail below.

3, the opening of a diaphragm of the diaphragm device 302 is imaged on the surface of the card body 204. In contrast to the embodiment of a laser marking device 200 shown in FIG Laser marking device 300 by using an aperture both the shape and the size of the opening or the cross section of the aperture can be freely defined. In contrast to this, a glass fiber or the end of a glass fiber has

5 a defined, usually a circular or elliptical cross-section. If a corresponding screen is used, other geometric shapes can also be reproduced or generated on a card body.

.0

The components of the laser marking device 300 are arranged such that the optics 301 spread the entire cross-sectional area at the end of the optical fiber 104 onto the deflection devices 201 and 202 or the scanner mirrors

L5 depicts. The opening of the diaphragm 302 is imaged on the card body 204 via the lens 203. The optics 301 are dimensioned such that the aperture 302 is completely and largely homogeneously illuminated. In this case, an image of the opening of the aperture 302 is formed on the card body

10 204. This is the case if the ratio of

Aperture opening and image size on the card body is equal to the ratio of the distance between the aperture and lens 203 or the distance between the lens 203 and the card body.

.5

If, for example, the aperture of the diaphragm 302 is made square, a sharply delimited, uniformly or homogeneously blackened and / or colored surface, as in FIG

50 Example of the letter "A" shown using the

Generate laser marking device 300 on the card body 204. If the opening of the diaphragm 302 is, for example, honeycomb-shaped or hexagonal, it is also possible to close one of the pixels 501 by closely joining them together

55 sharply delineated, evenly or homogeneously blackened and / or colored surface, as also illustrated in FIG. 5 using the example of the letter "A", by means of the laser marking device 300 on the card body 204.

5

The letter "A" shown in FIGS. 4 and 5 was successively composed of squares 4.01 or hexagonal honeycombs 501 of the same size by corresponding laser irradiation. This causes the sloping ones to appear

.0 step edges of the letter "A". This effect can be reduced by reducing the geometric shapes. However, this has the consequence that the number of points to be labeled or generated increases and consequently the duration of the labeling increases

.5 extends the laser 101 accordingly.

To counteract this, an aperture or aperture device 302 can be used, the opening cross section of which can be variably adjusted. When using such an aperture

! 0 or aperture device, both large pixels or areas 601 and, in contrast, small pixels or areas 602, as shown in FIG. 6 again using the example of the letter "A", can be combined to form the letter "A". While the letter "A" of Figures 4 and 5

15 consists of 105 marking points, the letter "A" of FIG. 6 was generated from a total of 50 large and small marking points on the surface of the card body by means of the laser marking device 300 using a corresponding aperture device 302.

50 With the contour of the letter remaining the same, the number of required labeling points has been reduced by approximately half by using both simple and four times enlarged labeling points, as shown in FIG. 6. This reduces the time for the Inscription or the generation of such a letter about half.

According to an exemplary embodiment according to FIGS. 10 to 14, a raster device 10 is provided, by means of which marking points of different sizes can be produced in a targeted manner. The raster process effected by means of the raster device 10 enables a reduction in the printing time. In contrast to the embodiment according to FIG. 6 L0, the number of labeling points is minimized depending on the shape of the character to be labeled.

In the present exemplary embodiment, the grid device 10 is designed as a square grid device with a plurality of L5 square partial openings. Alternatively, the partial openings can have a different geometric shape, for example be linear, point-shaped, etc.

.0 The screening method according to the invention enables

Inscription of inscription characters, such as the letter "A", with a minimal number of inscription points. It can preferably be used in such a printing process in which the printing of the individual

.5 labeling points require a constant time regardless of their dimensioning. The use of the grid method thus enables the labeling time to be minimized.

The labeling of lettering characters, such as a stylized letter “A” according to FIG. 10, takes place in two steps. In a first step, scanning of the letter is carried out by means of the raster device 10 using a first coarse grid 11, a second

55 middle grid 12 and a third fine grid 13 performed. The result is a resulting raster image 14 of the letter “A”, composed of differently sized lettering points, according to FIG. 14, which can be stored as a black and white character template (bitmap) in a memory control unit (not shown). In a second step, then the lettering of the letter "A", as shown in FIG. 10, is carried out, with lettering points of different sizes being generated by the raster process.

To generate the raster image 14, a first raster 11 or a first template 15 with a plurality of relatively large square partial openings 16 of the same dimension are placed over the inscription 17 in a first step. If a partial opening 16 of the mask 15 completely coincides with a partial area of the source image of the inscription symbol 17 shown in FIG. 10, corresponding first large inscription points 19 are generated and stored in a first partial image 20. In the present exemplary embodiment, two large labeling points 19 have been detected, which are shown hatched for differentiation.

In a second step to form the resulting raster image 14, a second raster 12 or a second template 21 with a plurality of central square partial openings 22 of the same dimension is placed over the source image 17 modified as a result of the first raster process. In this modified source image, the areas 19 of the inscription character 17 captured by the first template 15 are left out because these areas of the character 17 are already reserved for the raster image to be formed. By detecting the area of the source image 17 captured by the partial openings 22, a second source image 23 can be generated with a plurality of middle labeling points 24. In a third and final step, the now modified source image is scanned by means of a third raster 13 or a third template 25 with a plurality of small partial openings 26. The partial openings 26 are chosen to be small enough to ensure a sufficiently large resolution of the source image 17 , After comparison with the modified source image 17, a third partial image 27 is thus formed with a plurality of small labeling points 28. The accuracy of the reproduction of the source image 17 or the labeling of the source image 17 is determined by the size of the small partial openings 26. To simplify the scanning process, the edge lengths of the other partial openings 16, 22 of the templates 15 and 21 form an integral multiple of the edge length of the small partial opening 26 of the third template 25.

The described raster or scanning method is carried out electronically by means of a raster program, by means of which stencils 15, 21, 25 are successively brought into alignment with the source image 17 and the corresponding partial images 20, 23, 27 are detected.

The source image 17 is scanned line by line or column by column. The corresponding partial images 20, 23, 27 are generated with the corresponding raster points 19, 24, 28, the regions of the source image 17 captured by the raster points 19, 24 being removed for the next scanning process. This ensures that the next template 21, 25 does not capture areas of the source image 17 that have already been captured by the previous template 15, 21.

When scanning using the software-generated template 15, 21, 25, the line-by-line scanning point becomes each moved further by the edge length of the partial opening 16, 22, 2 relevant for the respective mask 15, 21, 25. As a result, the computing time can be reduced, in particular in the case of the relatively large grid openings 16.

As a result of this scanning or the raster process, the raster image 14 is stored in a label database. A raster scanning method can be used to label a correspondingly stored character, in which the differently large labeling points 19, 24, 28 are applied to the card surface. The laser beam is guided line by line according to the specified raster image.

Alternatively, the scanning by means of the raster process can also take place during the actual labeling process, the labeling being carried out by means of the laser labeling device 300 after the optimized composition of the differently sized screen dots 19, 24, 28 has been identified. The peculiarity of the invention

Raster method consists in that by applying different rasters or stencils to the character to be labeled, labeling points of different sizes can be recognized, which leads to a time optimization of the subsequent labeling process. The

The raster program thus generates a number of templates which are placed over the source image 17, which is in electronic form. If a raster opening or a raster 19, 24, 28 completely coincides with a partial area of the source image 17, this raster point 19, 24, 28 is stored and used in the

Coordinate system as the local and size-based basis for the lettering point of the letter "A" to be labeled later. A further specific embodiment of a diaphragm device 302 is shown in FIG. 9. This is an aperture that is composed of segments 901 and 902. These segments can be moved towards and away from each other 5, ie execute opposite movements 903.

Depending on the position of the two segments 901 and 902, a square aperture of different sizes is thus obtained. Such an aperture has the advantage that the size of a labeling point can be set anywhere between the minimum and L0 of the maximum aperture.

In an alternative embodiment of the invention, the diaphragm, which is variable in cross section, is realized by a rotating body described in more detail in DE 44 29 110 C2, which is adjusted by L5, a so-called galvo scanner. At the

Using a galvo scanner is advantageous because it can be positioned quickly and precisely.

In a further embodiment of the invention, the in

20 its cross-section variable aperture through a

Revolver device realized. The turret device accommodates panels with openings of different sizes. The correct aperture is brought into the imaging beam path by quickly rotating the turret device during the exposure pauses or between the laser pulses of the laser 101 25.

In another embodiment of the invention, a diaphragm which is variable in its cross section is provided with diaphragms

30 different sized openings realized, which are mounted on a common slide or on a linearly movable bracket. It is only essential for the displaceable holder that the diaphragms brought into the beam path can be changed as desired between two successive 35 laser pulses. If one is faster If it should not be possible to change between the diaphragms, the first diaphragm opening, for example the largest aperture, and then the second diaphragm opening, for example the smallest aperture, can be used for laser marking.

In another embodiment of the invention, the diaphragm, which is variable in its cross section, is realized by a so-called digital mirror device (DMD). Such a digital mirror device is known from US Pat. No. 4,441,761 and is therefore not explained in more detail here.

If the coherent laser beam from a conventional laser 101 for laser marking a data carrier or card body 204 strikes a DMD, diffraction occurs at its micromirrors with dimensions in the μm range. Diffraction creates several diffraction maxima in addition to the zero order diffraction maximum. For laser marking, the higher order diffraction maxima would have to be filtered out. As a result, however, only part of the laser power output by the laser 101 would be usable. By using a multimode glass fiber 104 according to the invention, the coherence or the defined phase / time relationship of the laser beam is eliminated and disadvantageous diffraction does not occur at the DMD, which serves as a diaphragm 302 in one embodiment of the invention.

The use of a DMD as a variable diaphragm 302 in the laser marking device 300 shown in FIG. 3 permits the successive production of the letter "A" 700 shown in FIG. 7 on the basis of pixels or areas arranged in a tiled shape, of which the pixels 701 to 707 are exemplary are shown under the letter "A" in higher resolution. Comparing FIGS. 6 and 7, it is noticeable that a DMD increases the sharpness can produce a contoured letter that is nevertheless composed of individual pixels.

Furthermore, according to the invention, a DMD can be used as an intensity modulator of the laser power of a conventional laser 101. This can be particularly useful if its laser power cannot be changed from pulse to pulse. When using a DMD as an intensity modulator, a corresponding number of micromirrors is set so that it couples the power out of the imaging beam path. For example, if only every second DMD mirror is activated, the laser power of a pixel depicted on the data carrier to be labeled is reduced by 50 percent. If, for example, eight micromirrors on a DMD are combined to form a pixel or pixel, 256 gray levels can be generated in this way. Since the DMD component has significantly more mirrors, current embodiments have 1024 x 768 mirrors, for example, the properties described above can be used.

In a further embodiment of the invention, an LCD component in transmission is used as an aperture 302 instead of a DMD operated in reflection. The individually electrically controllable elements determine the shape of the object, for. B. a letter that is mapped to the data carrier and generated by a conventional laser 101 and a laser marking device 300 according to the invention on the data carrier or card body 204 by blackening and / or coloring the relevant point on the surface of the card body. Instead of an LCD component operated in transmission, an LCD component mirrored on the rear side can also be operated in reflection and used as an aperture. FIG. 8 shows a portrait that, according to the invention, was composed of triangles and squares and was generated on the card body 204 by means of the laser inscription device 300 shown in FIG. 3 using a corresponding aperture device 302. Such a diaphragm device 302 can be realized, for example, by a turret device, a slide or a linearly displaceable holder, in which two or more diaphragms with a predetermined opening, in the present example a first diaphragm with a square opening and a second diaphragm with a triangular opening, thereon are mounted. These diaphragms are then alternately brought into the beam path of the laser marking device 300 when the portrait is successively written on the card body 204. If the area of the two different basic elements of the portrait is identical, their gray value impression (with the same laser power) is also identical. In contrast to the portrait shown enlarged in FIG. 8, the individual pixels can preferably not be resolved with the naked eye. Instead of a regular arrangement of squares and triangles, it is also possible to use an irregular arrangement of such or other geometric shapes which represents encoded information provided in the portrait. For example, the binary value "0" can be assigned to a square and the binary value "1" to a triangle. For example, a digit sequence of zeros and ones could then be obtained by line-by-line scanning, decrypted using suitable software and compared with information stored or provided on the data carrier; in particular to check the authenticity of the data carrier.

However, the described method is not limited to the storage of binary information. Rather, by using more than two various types of apertures also represent information in the 3, 4, 5, etc. number system.

In a further embodiment of the invention (not shown) in the invention

Laser marking device 300 uses an aperture 302 that has an opening with a more complicated geometric shape. A more complex geometrical shape is to be understood as a shape whose outline is less regular than a square or hexagon. With such a more complicated geometric shape, it is generally not possible to produce a uniform, homogeneous surface on a card body 204, but the corresponding geometric shape can represent, for example, a logo, a coat of arms or the like. In this case, the pixels generated by the laser 101 of the laser marking device 300 also have the shape of the more complicated geometric shape. If the pixels are so small that they cannot be resolved with the naked eye, then the labeling according to the invention cannot easily be distinguished from the labeling using a conventional laser labeling system. Only through the enlarged view, e.g. B. with a magnifying glass, the individual pixels can be resolved. The method of labeling according to the invention by generating a large number of more complicated or complex geometric figures can be used both for the production of alphanumeric characters and for the production of halftone images, such as portraits. Such a complex aperture can e.g. B. can be realized by a mask that can be produced for example with a photolithographic process.

It goes without saying that the invention does not apply to laser marking for producing black / white and / or gray value / halftone elements on data carriers or card bodies is limited. Rather, the method according to the invention can also be used for colored laser marking.

Reference symbol list:

100 laser marking device (basic principle)

101 conventional laser for laser marking card bodies

102 laser beam

103 imaging optics

104 loop-shaped multimode glass fiber

105 laser beam

200 laser marking device 201 deflection device 202 deflection device

203 lens 204 card body

300 laser marking device 301 optics

302 aperture or aperture device

400 letter "A"

401 basic element or surface

500 letter "A" 501 basic element or surface

600 letter "A"

601 pixel or area

602 pixel or area

700 letter "A"

701 pixels

702 pixels

703 pixels 704 pixels 705 pixels

706 pixels

707 pixels

800 portrait

801 basic element or coding element

802 basic element or coding element

900 embodiment of the aperture device 302 901 segment

902 segment

903 opposite movements of the segments

Claims

Method and device for laser marking of data carriers, in particular card bodies

1. Procedure for creating a label on a

L5 data carrier, in particular a card body (204), using a laser beam (102) emerging from a laser (101), characterized in that the laser beam (102) or part of the laser beam

20 with regard to its power density distribution in

Beam cross section is homogenized by a homogenizing agent, in particular a multimode glass fiber (104), and the homogenized laser beam (105) generates at least one image point and / or a labeling surface on the data carrier, which has a largely homogeneous ¹ or uniform blackening and / or coloring.

2. The method according to claim 1, characterized in that the homogenizing agent (104) consists largely of a

30 Gaussian power density distribution in

Radiation cross section produces a largely rectangular power density distribution and / or that the homogenizing agent largely eliminates the coherence of laser light entering it. 35

3. The method according to claim 1 or 2, characterized in that the homogenizing agent, in particular a multimode glass fiber (104), is subjected to mechanical stress in such a way that the optical power is distributed as evenly as possible over the different modes of the homogenizing agent.

4. The method according to claim 3, characterized in that the homogenizing agent, such as in particular a multimode glass fiber (104), is bent and / or twisted and / or arranged in a loop to produce mechanical stress.

5. The method according to any one of claims 1 to 4, characterized in that the homogenization means (104) is formed by an optical element which has a largely abruptly changing refractive index along at least one spatial direction, such as in particular a step index glass fiber (104).

6. The method according to any one of claims 1 to 5, characterized in that between the multimode glass fiber (104) and the data carrier, in particular a card body (204), a lens (203), in particular a converging lens and / or a lens, is provided, the lens (203) being arranged such that the fiber end of the multimode glass fiber is largely imaged on the data carrier.

7. The method according to any one of claims 1 to 6, characterized in that between the homogenizing agent

(104) and the data carrier (204) a diaphragm and / or a diaphragm device (302), preferably with an opening, the cross section of which in relation to shape and / or Dimensions is adjustable, arranged and the opening is mapped on the data carrier (204).

8. The method according to claim 7, characterized in that the 5 diaphragm (302) is provided with an opening whose

Cross-section is wholly or partially square and / or honeycomb or hexagonal.

9. The method according to any one of claims 7 or 8, characterized in that the aperture (302) has an opening, the cross section of which is changed when the inscription is generated on the data carrier and / or that the inscription has at least points and / or areas has two different sizes (601, 602) L5.

10. The method according to any one of claims 7 to 9, characterized in that the diaphragm (302) with an adjustable opening has two segments 20 (901, 902) which can be moved in opposite directions.

11. The method according to any one of claims 7 to 9, characterized in that the diaphragm is formed with an adjustable opening by a rotating body. 25

12. The method according to any one of claims 7 to 9, characterized in that the diaphragm device (302) with adjustable opening is formed by two or more diaphragms each having a predetermined opening, which are arranged on a turret device.

13. The method according to any one of claims 7 to 9, characterized in that the diaphragm device (302) with an adjustable opening with two or more diaphragms

35 of a predetermined opening is formed in each case are arranged on a linearly displaceable, common slide.

14. The method according to any one of claims 1 to 13, characterized in that the label (17) is generated by a number of label points (19, 24, 28) of different sizes, such that the number of label points is minimized.

15. The method according to any one of claims 1 to 14, characterized in that the labeling after a scan by means of several successively on a source image

(17) of the character to be inscribed grid (11, 12, 15, 21, 25) takes place, the grids each having a plurality of partial openings (16, 22, 26) of the same dimension.

16. The method according to any one of claims 1 to 15, characterized in that the partial openings (16, 22, 26) of the grid (11, 12, 15, 21, 25) have a different dimension.

17. The method according to any one of claims 1 to 16, characterized in that the grids (11, 12, 13) are formed by successive comparison with a source image (17), wherein one with the partial opening (16) of the grid (11) covering partial area of the source image (17) is removed before the next raster (12, 13) is applied to the source image (17).

18. The method according to any one of claims 1 to 17, characterized in that the scanning is carried out by means of a raster program in a computer, which by comparing the raster (11, 12, 13) with the Source image (17) of the character generated raster image (14) is stored in a label character database.

19. The method according to claim 17, characterized in that 5 the scanning by means of a raster program in one

Computer is carried out, the raster image (14) generated by comparing the rasters (11, 12, 13, 15, 21, 25) with the source image (17) of the character being used directly for labeling the character. .0

20. The method according to any one of claims 1 to 19, characterized in that the raster image (14) is generated on the card by scanning a laser beam by the raster scan method.

L5

21. The method according to any one of claims 12 or 13, characterized in that the predetermined openings of the two or more screens have a largely same cross-sectional area with a different geometric

50 have shape, such as in particular triangular and square.

22. The method according to any one of claims 12 to 14, characterized in that a coding (801, 802) is applied to the data carrier by the two or more panels with 25 openings of different geometric shapes.

23. The method according to any one of claims 7 to 15, characterized in that at least one of the panels is provided with an opening, the cross section of which represents a largely complex geometric shape, this shape preferably serving as an authenticity feature.

24. The method according to any one of claims 7 to 16, characterized in that at least one of the diaphragms, preferably an aperture whose opening has a largely complex geometric shape, is produced by a photolithographic method.

25. The method according to any one of claims 7 to 17, characterized in that one or more of the diaphragms is formed by a so-called digital mirror device or DMD.

26. The method according to any one of claims 1 to 18, characterized in that the intensity or energy of the laser beam (105) for labeling is influenced by a DMD.

27. The method according to any one of claims 1 to 19, characterized in that the intensity or energy of the laser beam for labeling is influenced by a so-called liquid crystal display or LCD operated in transmission or reflection.

28. Laser marking device in which a method according to one or more of the preceding method claims is carried out.

29. Laser-labeled data carrier, which has been produced by a method according to one or more of the preceding method claims.