Masking plate, arrangement and method for producing at least one tactile grid element of a grid on or in a substrate

Abstract

The invention relates to a masking plate resistant to laser beams, an arrangement and a method for producing at least one tactilely detectable raster element (102) of a raster (104) on or in a substrate (100).The method comprises the steps of providing the substrate (100) from a substrate material and locally foaming the substrate material (100) with a laser beam (106) from a laser source (108), whereby the at least one grid element (102) of the grid (104) is produced, wherein a) a masking plate (110) which is resistant to the laser beam (106) is applied to the substrate (100) before the at least one grid element (102) is produced, which masking plate has at least one through-hole (112) adapted to the grid element (102), wherein the local foaming of the substrate material takes place through the at least one through-hole (112) of the masking plate (110); or wherein b) a guide tube serving to guide the laser beam (106) is placed on the substrate (100), wherein the raster element (102) is produced by the local foaming of the substrate material through the guide tube.

Description

[0001] The invention relates to a method for producing at least one tactilely detectable raster element of a raster on or in a substrate. The method comprises the steps of providing the substrate from a substrate material and locally foaming the substrate material with a laser beam from a laser source, thereby producing the at least one raster element of the raster. The invention also relates to an arrangement for carrying out the method and a masking plate used for carrying out the method.

[0002] A method of the type mentioned above can be found, for example, in DE 195 37 177 A1. In this method, a relief structure in the form of tactile, raised alphanumeric information is created on a substrate using laser radiation, forming Braille. This process exploits the fact that the plastic material of the substrate foams locally due to the interaction with the intense laser radiation, leading to a limited curvature of the card surface. This macroscopically visible foaming is caused by a change in or destruction of the polymer structure, by oxidation processes, by the formation of microscopically small soot particles, by the release of gases, etc. The various foaming options described above depend on the type of plastic material being irradiated, the laser wavelength of the laser source, and the intensity and duration of the laser irradiation.

[0003] The use of a laser to write on substrates, particularly when they are in card form, has the advantage that personalized data can be individually applied to the identity cards. When foaming to create the tactilely detectable grid elements, it has been shown that it is very complex to maintain a precise contour, and thus a high level of dimensional accuracy, of the grid elements. This can manifest itself, for example, in the fact that there is no longer a sufficiently sharp-edged transition from the grid element to the surface of the substrate, and the necessary height of the grid elements for them to be easily detectable by tactile detection is difficult to achieve. If an attempt is then made to achieve the required height of the tactilely detectable grid element, the material may burst at the point exposed to the laser due to the increased energy input of the laser beam.

[0004] It is therefore the object of the present invention to provide a method, an arrangement and a masking plate which take the above disadvantages into account.

[0005] This object is achieved by a method having the features of claim 1, by an arrangement having the features of claim 6, and by a masking plate having the features of claim 11. Advantageous embodiments with expedient further developments of the invention are specified in the dependent claims.

[0006] The method according to the invention is characterized in particular in that a masking plate resistant to the laser beam is applied to the substrate before the at least one grid element is produced, wherein the masking plate has at least one through-hole adapted to the grid element, preferably a plurality of through-holes adapted to the grid, wherein the local foaming of the substrate material takes place through the at least one through-hole of the masking plate.

[0007] Alternatively, the method according to the invention is characterized in that a guide tube serving to guide the laser beam is placed on the substrate, wherein the raster element is generated by the local foaming of the substrate material through the guide gate.

[0008] The use of a masking plate with a through-hole or the use of a guide tube ensures that the foaming of the substrate material is limited to the cross-section of the through-hole or to the cross-section of the inner diameter of the guide tube. In other words, the foamed substrate material can only expand into the free space of the guide tube or through-hole, which is why the required height for the tactile detection of the grid element can be more easily achieved; thus, less energy input is required. In addition, a sharp-edged transition from the unfoamed surface of the substrate to the tactilely detectable grid element is formed due to the given limitation provided by the guide gate or through-hole.

[0009] A masking plate is a plate that provides a type of "mask" for the local foaming of the substrate material. If the laser beam hits the masking plate in an area away from a through-hole, this does not cause the substrate material to foam, which is therefore concealed and protected by the material of the masking plate. However, if the laser beam passes through the through-hole, this leads to foaming of the substrate material, since the masking plate does not provide protection there. A masking plate does not necessarily mean a "plate" in the narrow sense, one with very large dimensions; it can also be in the form of a sheet metal or the like. The plate is made, for example, of a metal that is resistant to the laser radiation used.

[0010] A guide tube is a tube with a particularly round cross-section and is suitable for guiding the laser beam to the substrate. However, the guide tube itself is resistant to the laser radiation used.

[0011] The process is particularly well-suited for creating tactilely detectable raster elements when the raster is adapted to a character of an alphabet, with the alphabet being selected from the group comprising Braille, Raphigraphy, Barbier, Dotcode, and Fakoo. All characters in these alphabets are subject to a raster-like system. They can therefore be easily created by foaming the substrate material using a laser.

[0012] The clear diameter of the guide tube or the clear diameter of the through hole, which is applied to the substrate during local foaming of the substrate material, corresponds to the dimensions of the character of the alphabet which is to be introduced into the substrate.

[0013] The through holes of the masking plate can be adapted in terms of their number, their spacing from one another and their dimensions (or their clear diameter) to the alphabet of the character to be introduced into the substrate.

[0014] In order to ensure a sharp-edged transition between the unfoamed surface of the substrate material and the tactilely detectable grid element produced, it is further advantageous if the substrate and the masking plate or the substrate and the guide tube are pressed together before the at least one grid element is produced and remain pressed together during the local foaming.

[0015] The through-hole in the masking plate can be shaped with an identical cross-section along its length, which in particular corresponds to the diameter of the raster element to be foamed. In this case, the laser beam is aligned along a central longitudinal axis of the through-hole during the creation of the at least one raster element. To introduce multiple raster elements into the substrate, the substrate is then displaced relative to the laser source. For this purpose, for example, the laser source or the coupling-out of the laser beam is carried out on a multi-axis adjustable holding arm. Alternatively, the laser source or the coupling-out of the laser beam can also be stationary, in which case the substrate is adjusted appropriately; for example, using a workpiece carrier for holding the substrate, which can be moved by a drive device.

[0016] In order to introduce a plurality of grid elements into the substrate material, i.e., to foam them, it has proven advantageous if, during the creation of the at least one grid element, the laser beam is aligned at an angle deviating from zero degrees, even from 360 degrees, with respect to a central longitudinal axis of the through-hole. For this purpose, the at least one through-hole can be formed so as to widen toward its surface facing the laser source.

[0017] The advantages, embodiments and technical effects explained in connection with the method according to the invention apply equally to the arrangement according to the invention.

[0018] The arrangement for generating at least one tactilely detectable raster element of a raster on or in a substrate comprises a laser source. The laser source is configured to locally foam a substrate material of the substrate using a laser beam, thereby generating the at least one raster element of the raster. A masking plate resistant to the laser beam is provided and configured to be applied to the substrate. The masking plate has at least one through-hole adapted to the raster element, preferably a plurality of through-holes adapted to the raster, so that the local foaming of the substrate material occurs through the at least one through-hole of the masking plate.

[0019] This arrangement allows for a particularly reliable foaming process for creating a grid element that is subsequently easily detectable by touch. It has a sharp edge relative to the surface of the unfoamed substrate material and a height that is easily detectable by touch.

[0020] The underlying grid is preferably the grid of a character of an alphabet selected from the group comprising Braille, Raphigraphy, Barbier, Dotcode and Fakoo.

[0021] In order to achieve a sharp-edged formation of the grid element with respect to the unfoamed surface of the substrate, it is advantageous if a clamping device is present which is designed to press the substrate and the masking plate together before the production of the at least one grid element and to keep them pressed together during the local foaming.

[0022] Here, too, it is advantageous if the masking plate is aligned with respect to the laser source or laser beam such that, when generating the at least one raster element, the laser beam is aligned along a central longitudinal axis of the through-hole. This allows targeted energy to be introduced into the substrate material to foam it and thereby create the tactilely detectable raster element.

[0023] In order to be able to produce several raster elements with one and the same laser device, it is advantageous if the through-hole of the masking plate is formed so as to widen towards its surface facing the laser source, and if the laser source or the laser beam is aligned with respect to the masking plate in such a way that when producing the at least one raster element, the laser beam is aligned at an angle deviating from 0 degrees and also from 360 degrees with respect to a central longitudinal axis of the through-hole.

[0024] The advantages, advantageous embodiments and technical effects explained in connection with the method according to the invention and the arrangement according to the invention apply equally to the masking plate according to the invention.

[0025] The masking plate according to the invention serves to create at least one tactilely detectable grid element of a grid on or in a substrate formed from a substrate material. The masking plate is formed from a material resistant to a laser beam from a laser source and is designed to be applied to the substrate. To create the at least one grid element by locally foaming the substrate material, the masking plate has at least one through-hole adapted to the grid element, so that the local foaming of the substrate material occurs through the at least one through-hole.

[0026] The through-hole can have a circular disk shape in cross-section. This creates a dot-shaped grid element. Other cross-sectional shapes, such as a polygon, are also possible. The masking plate serves to specifically foam the substrate material so that the grid element, which will later be tactilely detectable, is clearly demarcated from the unfoamed surface of the substrate. Furthermore, the grid element created in this way has the required height for tactile detection, even with lower energy input.

[0027] To speed up production, it is advantageous if the masking plate has several through holes adapted to the grid in order to create several grid elements by locally foaming the substrate material.

[0028] In this context, it is possible for the grid and thus the through holes to be adapted to a character of an alphabet selected from the group comprising Braille, Raphigraphy, Barbier, Dotcode and Fakoo.

[0029] To easily create entire lines of text, it has proven advantageous to have a number of through holes that correspond to at least two of the alphabetic characters, forming a writing matrix. A number of through holes that form more than two characters is also possible.

[0030] To reduce the number of required movements between the laser beam output and the substrate material, for example, by simply changing the direction of the laser beam, multiple through holes can be served by one and the same laser head. In this case, the at least one through hole is formed in a widening manner, starting from a surface facing the substrate to be processed and extending to a surface facing away from the substrate.

[0031] The substrate is, for example, a blank for a passport, identity card, driver's license, or other ID card. The substrate can also be a blank for an access control card, a vehicle registration document, a vehicle title, a visa, a check, or even a check, bank, credit, or cash payment card, a customer card, a health card, or a chip card. Furthermore, the substrate can be a blank for a company ID card, a credential, a membership card, or another ID document.

[0032] Preferably, the substrate itself is already available in ID 1, ID 2, ID 3, or any other format. The substrate is generally preferably a laminate of multiple document layers that are bonded together under heat and increased pressure.

[0033] The substrate can preferably be formed from a polymer selected from a group comprising polycarbonate (PC), in particular bisphenol A polycarbonate or a polycarbonate formed with a geminal disubstituted bis(hydroxyphenyl)cycloalkane, polyethylene terephthalate (PET), and derivatives thereof, such as glycol-modified PET (PETG), polyethylene naphthalate (PEN), polyvinyl chloride (PVC), polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyimide (PI), polyvinyl alcohol (PVA), polystyrene (PS), polyvinylphenol (PVP), polypropylene (PP), polyethylene (PE), thermoplastic elastomers (TPE), in particular thermoplastic polyurethane (TPU), acrylonitrile-butadiene-styrene copolymer (ABS), and derivatives thereof. Foaming is ensured, for example, by adding particles of foaming agents that expand under the influence of monochromatic radiation of a specific wavelength.Furthermore, the substrate can also be made from several of these materials. It is preferably made of PC or PC / TPU / PC. The polymers can be either filled or unfilled. In the latter case, they are preferably transparent or translucent. If the polymers are filled, they are opaque. The above information refers both to films to be bonded together and to liquid formulations that are applied to a precursor of the blank or the substrate, such as a protective or topcoat. The blank is preferably made from three to twelve, preferably four to ten films. The films can also carry printing layers. A laminate formed in this way can finally also be coated on one or both sides with a protective or topcoat or with a protective film.The film can, in particular, be a volume hologram, a film with a surface hologram (e.g., a cinematic element), or a scratch-resistant film. Overlay layers formed in this way additionally provide the substrate with the required abrasion resistance.

[0034] It is generally noted that all features disclosed with respect to specific aspects or embodiments of the invention can also be combined with other aspects or embodiments of the invention in a technically reasonable manner. This also applies across different technical subject matters and subject matter categories. In particular, this also applies in part to individual features, unless explicitly stated herein or it is obvious from a technical contradiction that an inextricable functional-technical connection exists between certain features, which must be maintained to implement the invention.

[0035] The invention is explained below using an exemplary embodiment and its outline. Herein: Figure 1 shows a cross section through an arrangement for producing at least one tactilely detectable raster element of a raster on or in a substrate, in which the laser beam is aligned coaxially with respect to the central longitudinal axes of the through-holes; Figure 2 shows a plan view of the masking plate (the masking plate, the masking strip or the masking sheet) of the arrangement of Figure 1 ; Figure 3 shows a cross section through a further arrangement for producing at least one tactilely detectable raster element of a raster on or in a substrate, in which the laser beam is not aligned coaxially, but inclined with respect to the central longitudinal axes of the through-holes; Figure 4 shows a plan view of the masking plate (the masking plate, the masking strip or the masking sheet) of the arrangement of Figure 3 ; Figure 5 a substrate with tactile detectable raster elements produced by the method according to the invention; Figure 6 one of the Figure 5 corresponding view of a substrate with tactilely detectable raster elements that were not produced using the method according to the invention; and Figure 7 shows a schematic process sequence for producing the at least one tactilely detectable raster element.

[0036] In Figure 11 illustrates an arrangement for producing at least one tactilely detectable raster element 102 of a raster 104 on or in a substrate 100. The arrangement shown comprises a laser source 108 that emits a laser beam 106. The laser beam is used to locally foam the substrate material of the substrate 100, thereby producing the at least one raster element 102 of the raster 104. A masking plate 110 formed with a plurality of through-holes 112 is also present between the laser source 108 and the substrate 100 to be locally foamed. The through-holes 112 are adapted to the dimensions of the raster element 102 to be produced, with the local foaming of the substrate material taking place through the through-holes 112 of the masking plate 110. For this purpose, the material of the masking plate 110 itself is resistant to the laser beam 106 used.

[0037] In the present case, the grid elements 102 form a grid 104, with which the characters of a Braille alphabet can be generated by local foaming. However, the present application is not limited to the Braille alphabet. Instead of a Braille alphabet, any other grid-like, particularly dot-like, system is also possible.

[0038] In Figure 2 is a plan view - not to scale with regard to the Braille alphabet - of the masking plate 110 from Figure 1shown. The masking plate 110 comprises, purely by way of example, three Braille characters with a maximum of six dots; the Braille character is often also referred to as a shape. Braille characters with eight dots are also possible. The tactilely detectable grid elements 102 should have a height of between 5 millimeters (mm) and 10 mm, with a height of 6 mm to 7 mm being typical. The distances between the individual dots, thus the distances between the central longitudinal axes 114 of adjacent through-holes 112, are approximately 2.5 mm in the present case. The diameter of the tactilely detectable grid elements 102 to be produced corresponds to approximately 1.5 mm. The distances between the individual grids 104, thus between the individual Braille characters, are 6 mm, with the line spacing of the individual grids 104 being approximately 10 mm. The present masking plate 110 forms a writing matrix 120 due to the use of more than one character of the alphabet.For example, three of the characters of the alphabet are specified by the writing matrix 120 illustrated with a dashed frame. A different number of grids 104 and a different number of characters are also possible, so that four, five, six, and even up to 25 characters can be present in the writing matrix 120.

[0039] Figure 3shows a case in which the laser beam 106 of the laser source 108 does not impinge perpendicularly on the substrate 100 and thus does not run parallel with respect to the central longitudinal axis 114 of the through-holes 112 in the masking plate 110. For this reason, the masking plate 110 is conical in the region of its through-holes 112. This allows an inclination angle of the laser beam 106 with respect to the central longitudinal axis 114 of the through-hole 112. Thus, the tactilely detectable raster element 102 is then locally foamed by the laser beam 106 at an angle—different from zero degrees and different from 360 degrees—with respect to the central longitudinal axis 114.

[0040] The associated masking plate 110 is shown in a top view by way of example in Figure 4illustrated. Here, too, the area of ​​the writing matrix 120 is again outlined in dashed lines. It can be seen that the through-holes 112 are formed in a widening manner, namely from a surface 116 facing the substrate 100 to be processed to a surface 118 facing away from the substrate 100.

[0041] In Figure 5 the result of the local foaming of the substrate 100 is visible, wherein, as evidenced by the dotted area, the tactilely detectable grid elements 102 are very clearly demarcated from the surface of the unfoamed substrate area.

[0042] For comparison, Figure 6 a locally foamed substrate 100 is shown in which no such masking plate 110 with through holes 112 was used, whereby the dotted areas of the tactilely detectable raster elements 102 "blur"; the raster elements 102 thus also remain in height behind the raster elements 102 according to Figure 5back.

[0043] Based on Figure 7 The method for producing the grid 104 with such tactilely detectable grid elements 102 on or in a substrate 100 is shown. First, in step S100, the substrate 100 is prepared from a substrate material.

[0044] In step S200, the masking plate 110 is placed or applied to the substrate 100 in a precisely positioned manner. Subsequently, in step S300, the substrate 100 and the masking plate 110 are pressed together so that the masking plate 110, with its through-holes 112, bears against the substrate material, thus against the surface 118, under pressure. This leads to better results with regard to the delimitation of the tactilely detectable grid element 102 and the unfoamed surface of the substrate 100. Subsequently, in step S400, the at least one grid element 102 is created by locally foaming the substrate material, specifically through the through-hole 112 of the masking plate 110. The pressing force generated in step S300 is maintained. After the desired grid elements 102 have been created, the pressing force is released (step S500) and the partially foamed substrate is freed from the masking plate (step S600).

[0045] As a result, the present invention creates the possibility of forming grid elements 102 on a substrate 100 in a simplified manner by local foaming, which subsequently also leads to a sharper demarcation compared to the unfoamed surface. The characters or letters thus produced are thus easier to detect tactilely. List of reference symbols

[0046] 100Substrate 102Grid element 104Grid 106Laser beam 108Laser source 110Masking plate 112Through hole 114Central longitudinal axis 116Surface (facing the substrate) 118Surface (facing the laser source) 120Writing matrix S100Step: Substrate prepared from substrate material S200Step: Place masking plate on substrate S300Step: Pressing masking plate and substrate together S400Step: Generating at least one raster element (laser) S500Step: Releasing the pressing force S600Step: Separating the masking plate from the substrate

Claims

1. A method for producing at least one tactilely detectable raster element (102) of a raster (104) on or in a substrate (100), comprising the steps of providing the substrate (100) from a substrate material and locally foaming the substrate material (100) with a laser beam (106) of a laser source (108), whereby the at least one raster element (102) of the raster (104) is produced, characterized in thata) a masking plate (110) which is resistant to the laser beam (106) is applied to the substrate (100) before the at least one raster element (102) is produced, said masking plate having at least one through-hole (112) adapted to the raster element (102), wherein the local foaming of the substrate material takes place through the at least one through-hole (112) of the masking plate (110); or b) a guide tube which serves to guide the laser beam (106) is placed on the substrate (100), wherein the raster element (102) is produced by the local foaming of the substrate material through the guide tube.

2. Method according to claim 1, characterized in that the grid (104) is adapted to a character of an alphabet selected from the group comprising Braille, Raphigraphy, Barbier, Dotcode and Fakoo.

3. Method according to claim 1 or 2, characterized in thatthe substrate (100) and the masking plate (110) or the substrate (100) and the guide tube are pressed together before the production of the at least one grid element (102) and remain pressed together during the local foaming.

4. Method according to one of claims 1 to 3, characterized in that when producing the at least one raster element (102), the laser beam (106) is aligned along a central longitudinal axis (114) of the through-hole (112).

5. Method according to one of claims 1 to 4, characterized in that when producing the at least one raster element (102), the laser beam (106) is aligned at an angle deviating from zero degrees with respect to a central longitudinal axis (114) of the through-hole (112), for which purpose the through-hole (112) is formed widening towards its surface (116) facing the laser source (108).

6. Arrangement for producing at least one tactilely detectable raster element (102) of a raster (104) on or in a substrate (100), comprising a laser source (108) which is configured to locally foam a substrate material of the substrate (100) by means of a laser beam (106) in order to thereby produce the at least one raster element (102) of the raster (104), characterized in that a masking plate (110) which is resistant to the laser beam (106) and is designed to be applied to the substrate (100), wherein the masking plate (110) has at least one through-hole (112) adapted to the grid element (102), so that the local foaming of the substrate material takes place through the at least one through-hole (112) of the masking plate (110).

7. Arrangement according to claim 6, characterized in thatthe grid (104) is adapted to a character of an alphabet selected from the group comprising Braille, Raphigraphy, Barbier, Dotcode and Fakoo.

8. Arrangement according to claim 6 or 7, characterized in that a clamping device is provided which is configured to press the substrate (100) and the masking plate (110) together before the production of the at least one grid element (102) and to keep them pressed together during the local foaming.

9. Arrangement according to one of claims 6 to 8, characterized in that the laser source (108) is aligned with respect to the masking plate (110) such that when generating the at least one raster element (102), the laser beam (106) is aligned along a central longitudinal axis (114) of the through-hole (112).

10. Arrangement according to one of claims 6 to 9, characterized in thatthe through-hole (112) of the masking plate (110) is formed widening towards its surface (116) facing the laser source (108), and in that the laser source (108) is aligned with respect to the masking plate (110) such that when generating the at least one raster element (102), the laser beam (106) is aligned at an angle deviating from zero degrees with respect to a central longitudinal axis (114) of the through-hole (112).

11. Masking plate (110) for producing at least one tactilely detectable raster element (102) of a raster (104) on or in a substrate (100) made of a substrate material, which masking plate is formed from a material resistant to a laser beam (106) from a laser source (108) and is designed to be applied to the substrate (100), and which, for producing the at least one raster element (102) by locally foaming the substrate material, has at least one through-hole (112) adapted to the raster element (102) in such a way that the local foaming of the substrate material takes place through the at least one through-hole (112).

12. Masking plate (110) according to claim 11, characterized in that a plurality of through holes (112) adapted to the grid (104) are provided in order to produce a plurality of grid elements (102) by local foaming of the substrate material.

13. Masking plate (110) according to claim 12, characterized in thatthe grid (104) and thus the through holes (112) are adapted to a character of an alphabet which is selected from the group comprising Braille, Raphigraphy, Barbier, Dotcode and Fakoo.

14. Masking plate (110) according to claim 13, characterized in that a number of through holes (112) are present which are adapted to at least two of the characters of the alphabet so that they form a writing matrix (120).

15. Masking plate (110) according to one of claims 11 to 14, characterized in that the at least one through-hole (112) is formed in a widening manner, starting from a surface (116) facing the substrate (100) to be processed towards a surface (118) facing away from the substrate (100).

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