METHOD FOR PRODUCING A CARD BODY, CARD BODY FOR A CHIP CARD AND CHIP CARD

Description

[0001] The invention relates to a method for producing a card body for a chip card, a card body for a chip card and a chip card comprising a card body.

[0002] Card bodies with a metallic core in the form of a metallic core layer or metallic core element are considered, as are cards with dual interface (DI) functionality, in which the card body is partially or entirely made of metal. The energy coupling of DI systems with a two-coil system is achieved through metal structures with a slot, in which the magnetic / current flow is redirected in the metal surfaces. In this way, the slot prevents short-circuit current.

[0003] The chip module is inserted into a cavity or module opening in the card body.

[0004] Such a card works by using a chip module that contains a coil (Coil-On Module). This coil couples to the metal card body. This coupling only works if the slot is present in the metal card body.

[0005] However, the slit causes the card to become unstable in this area. Since the cut extends to the module opening, it can also cause damage to the module, for example, due to shear forces.

[0006] The fundamental disadvantage of the slot is not only the instability near the module opening, but also the fact that the plastic films with which the metallic card cores are typically coated sag in the slot area during lamination. This leads to a degraded appearance.

[0007] Even the variant of card production in which the metallic layer is not covered with plastic film but only with a protective varnish makes the slit clearly visible, so that the appearance is impaired.

[0008] US 2020 / 364527 A1 describes a transaction card comprising a card body with a slot. A first portion of the slot is formed at a first angle, and a third portion of the slot is formed at a third angle. A card body can be manufactured by positioning the card body at a first angle with respect to a cutting device and creating a first portion of a slot at the first angle, at least by moving the card body over the cutting device or by moving the cutting device over it, stopping the movement of the card body, rotating the card body through a third angle to create a second portion of the slot; and creating a third portion of the slot at the third angle by at least moving the card body over the cutting device or moving the cutter over the card body.

[0009] US 2019 / 156073 A1 describes smart cards comprising (i) a metal card body (MCB) with a slot (S) overlapping a module antenna (MA) of a chip module (TCM), or (ii) multiple metal layers (M1, M2, M3), each having a slot (S1, S2, S3) offset from one another or differently aligned. A front metal layer may be continuous and may be shielded from underlying metal layers by a shielding layer (SL).

[0010] The object of the present invention is therefore to improve the stability of the card body and the chip card in the area of ​​the slot.

[0011] This object is achieved by a method for producing a card body for a chip card, a card body for a chip card, and a chip card comprising a card body according to the independent patent claims. Embodiments and developments of the invention are specified in the dependent claims.

[0012] A method according to the invention for producing a card body for a chip card comprises the steps: Providing a metallic base body with two opposing main surfaces and a circumferential surface connecting the two main surfaces, wherein a module opening for receiving a chip module has already been created in the base body or is still being created in a module opening zone, and creating a slot on the circumferential surface between the two main surfaces, wherein the slot is formed from the circumferential surface up to the module opening or up to the module opening zone, and wherein an entry angle of the slot at least in one of the two main surfaces is not equal to ninety degrees to the main surface.

[0013] A basic idea of ​​the present invention is that the slot in the metallic base body is no longer formed perpendicular to the main surface, but at an angle other than 90°. In other words, the slot, or at least an entry region of the slot on the main surface, runs obliquely to the main surface. This leads to an overlap of regions of the metallic base body separated by the slot in a direction perpendicular to the main surfaces. This overlap can prevent shearing movement in at least one direction.

[0014] The slot proposed here stabilizes the card body against shear. Another advantage is that the cover films, such as plastic ones, are less likely to sag into the slot area, as the angled entry of the slot provides support for such a film. Furthermore, the slot can now be filled with an adhesive or other material, as the angled slot prevents or at least significantly reduces the leakage of the adhesive or material.

[0015] The slot proposed here has the advantage that the angled design improves the mechanical and structural stability of the card body and also prevents or significantly improves the risk of the foil sagging into the slot. Another advantage is that this machining from the front face reduces the amount of chips that can accumulate in the slot, both from cutting the card from the solid material and from creating the module opening.

[0016] The entry angle of the slot into the metallic base body is defined here as the angle of the slot to the main surface. This angle can also be referred to as the exit angle, since this angle is not subject to any functionality with regard to entry or exit.

[0017] When creating the slot, the main axis of the tool used to create the slot can be aligned parallel to the main surfaces, and the slot can be created starting at the peripheral surface and extending toward and up to the module opening (or the corresponding zone for the module opening). For example, a milling cutter or laser can work perpendicular to the peripheral surface to create the slot, or it can be aligned and work from the peripheral surface into the metallic base body.

[0018] The slot may be formed by a serration cut that provides an overlap between two opposing walls of the slot. A serration cut is understood to be a cut in which one or more such overlaps are present along the length of the slot. This overlap or overlaps prevent shearing or bending of the card body in one or more directions. The two main directions in which shearing or bending is to be prevented are the two normal vectors to the two main surfaces. One or more serrations in the cut are achieved by changes in direction when creating the cut.This means that if a milling cutter or laser is aligned perpendicular to the peripheral surface to create the slot, then it can be gradually moved from one main surface to the other main surface while maintaining the same alignment, undergoing the changes in direction to create the gear or gears.

[0019] It can also be provided that the slot is cut with a laser, and preferably that the laser focus is readjusted as the cutting depth increases. This way, the laser focus can always be on the cutting point, ensuring optimal material removal. Instead of a laser, for example, waterjet cutting or a milling machine can be used.

[0020] It can be provided that at least one region of the slot is curved, so that a first wall of the slot has a concave region and an opposite second wall of the slot has a convex region, wherein the convex region engages in the concave region. Several concave regions and corresponding convex regions can also be formed along the slot from one main surface to the second main surface. With such a curved course of the slot, shearing of the card body and thus of the chip card in both main directions can be effectively prevented or limited. In particular, a round or curved creation of the slot minimizes the formation of burrs in the slot.

[0021] It can further be provided that, during the creation of the slot, a change in direction is made such that the slot is wedge-shaped between the two main surfaces. As mentioned, a wedge-shaped slot can effectively prevent or limit shearing of the card body and thus of the chip card in both main directions. The change in direction, for example, of a laser, can then occur at the point of the wedge tip during the creation of the slot.

[0022] It can be provided that a plastic layer is applied to each of the main surfaces using an adhesive, with the slot being at least partially filled with the adhesive. The plastic layers can, for example, already be covered with the adhesive when they are applied to the main surfaces. The still liquid or viscous adhesive then runs into the angled slot. Due to the angle and / or one or more changes in direction of the slot, the adhesive remains in the slot and does not run out. The then hardening adhesive holds the walls of the slot in position, whereby twisting or shearing of the card body and thus of the chip card is further complicated or prevented. In addition, the risk of a short circuit can be further reduced because the adhesive prevents contact between the walls of the slot.

[0023] It can also be provided that the module opening is created only after the plastic layers have been applied. The slot creation proposed here can thus be used in various phases of the production of a card body or a chip card.

[0024] A card body according to the invention for a chip card comprises a metallic base body with two opposite main surfaces and a circumferential surface connecting the two main surfaces, wherein a module opening for receiving a chip module has already been created in the base body or is still being created in a module opening zone, and a slot which extends from the circumferential surface of the base body to the module opening or to the module opening zone and which extends between the two main surfaces, wherein an entry angle of the slot at least in one main surface is not equal to 90° to the main surface.

[0025] The same advantages and modifications apply as previously described.

[0026] The module opening is formed as a through-hole or as a blind hole in one of the main surfaces of the metallic base body or the card body.

[0027] When creating the slot, either the module opening or the corresponding module opening zone in which the module opening will later be formed is present.

[0028] It can be provided that the entrance angle is less than or equal to 82°, preferably between 30° and 60°, and most preferably 45°. It has been shown that such angles, depending on the thickness of the metallic base body and the slot width, offer good coverage of the regions of the metallic base body separated by the slot. For example, with a base body thickness of 500 µm and a cutting width and thus slot width of 50 µm, good coverage of the regions separated by the slot begins at an angle of approximately 80° to 82°. This means that the regions of the metallic base body separated by the slot partially ''overlap'' one another when viewed perpendicularly onto one of the main surfaces.

[0029] It can further be provided that the slot is formed by a serrated cut, which provides an overlap between two opposing walls of the slot. A serrated cut is understood here to be a cut in which one or more such overlaps are present along the length of the slot. This overlap or overlaps prevent shearing or bending of the card body in one or more directions. The two main directions in which shearing or bending is to be prevented are the two normal vectors to the two main surfaces.

[0030] It can be provided that a first wall of the slot has a concave region and that an opposite second wall of the slot has a convex region, wherein the convex region engages in the concave region. The concave and convex course of the wall surfaces is considered in the direction from one main surface to the other main surface. Several concave regions and corresponding convex regions can also be formed along the slot from one main surface to the second main surface. With such a curved course of the slot between the two main surfaces, shearing of the card body and thus of the chip card in both main directions can be effectively prevented or limited.

[0031] It can further be provided that the slot between the two main surfaces is wedge-shaped. With a wedge-shaped slot, shearing of the card body and thus of the chip card in both main directions can be effectively prevented or limited. One side of the wedge prevents shearing movement in one of the two main directions. A symmetrical wedge cut can be provided, in which a wedge tip of the slot lies in a central plane of the card body and both legs have the same entry angle. Furthermore, an asymmetrical wedge cut can be provided, in which the lengths and also the entry angles of the two legs of the wedge-shaped slot are different.

[0032] One or two undercuts may be provided in the area of ​​a wedge tip of the slot. These undercuts can be formed, for example, by extending the legs of the wedge-shaped slot beyond the intersection of the two legs, i.e., beyond the wedge tip. One advantage of this undercut is that the walls of the slot can have fewer burrs at the intersection or crossing point of the two legs. This can prevent the risk of short circuits caused by contact between the opposing walls of the slot. At the same time, the blind hole of the undercut can serve as a repository for chips generated during production.

[0033] A chip card according to the invention comprises a card body as described above and a chip module at least partially embedded in the module opening of the card body. The same advantages and modifications apply as described above. The card body comprises a metallic base body and can be designed with or without plastic cover layers.

[0034] The present invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1: a top view of a card body for a chip card; Fig. 2: a sectional view of the card body according to Fig. 1 along the line II; Fig. 3: a view of a front side of the card body from Fig. 1; Fig. 4: a partial view of an end face of a card body with a slot according to a first exemplary embodiment, which does not fall under the scope of the claims; Fig. 5: a partial view of an end face of a card body with a slot according to a second exemplary embodiment; Fig. 6: a partial view of an end face of a card body with a slot according to a third exemplary embodiment; Fig. 7: a partial view of an end face of a card body with a slot according to a fourth exemplary embodiment; Fig. 8: a partial view of an end face of a card body with a slot according to a fifth exemplary embodiment; Fig. 9: a partial view of an end face of a card body with a slot according to a sixth exemplary embodiment; Fig. 10: a sectional view of a chip card with card body and chip module; and Fig. 11: a schematic representation of a method for producing a card body.

[0035] Fig. 1shows a card body 10 for a chip card. The card body 10 has a metallic base body 11 with two opposite main surfaces, of which one main surface 12 is Fig. 1 The other, opposite main surface 13 is in Fig. 2 The two main surfaces 12, 13 run parallel to each other and are connected by a circumferential surface 14. The metallic base body 11 can, for example, be in the form of a core or a layer made of a stainless steel alloy, for example, with a thickness of 400 µm. The thickness of the base body 11 can, for example, be between 50 µm and 920 µm.

[0036] The metallic base body 11 has a rectangular shape in an xy-plane, in which the peripheral surface 14 lies with two longitudinal surfaces 15 extending in the x-direction and two end faces 16 extending in the y-direction. The thickness of the base body 11 extends in the z-direction.

[0037] A module opening 17 for a chip module is provided in the main surface 12 of the card body 10. The module opening 17 extends through the entire metallic base body 11, but can also be formed as a blind hole. It can also be created later. The module opening 17 is created, for example, by means of a laser or milling process.

[0038] A slot 18 is provided in the metallic base body 11, which extends from the peripheral surface 14, or in other words, from an outer edge of the metallic base body 11, to the module opening 17. Thus, the slot 18 connects the module opening 17 to the peripheral surface 14. The slot 18 runs in the y-direction, i.e., parallel to the longitudinal surface 15. The slot 18 has, for example, a width between 30 µm and 100 µm, preferably between 50 µm and 80 µm.

[0039] In Fig. 1The slot 18 is shown on the left side. The slot 18 can also be arranged on the right, upper, or lower side of the base body 11. The slot 18 serves to prevent short-circuit currents or eddy currents.

[0040] Fig. 2 shows a sectional view of the map body 10 along the line II of Fig. 1 It can be seen that the slot 18 completely cuts through the base body 11 in its thickness or height, i.e., in the z-direction. The slot 18 thus connects the two main surfaces 12, 13. The slot 18 extends in the y-direction to the module opening 17.

[0041] Fig. 3shows a view of the longitudinal surface 15 of the card body 10. In this case, the card body 10 or the metallic base body 11 has already been cut out. The module opening 17 has also already been recessed in the base body 11, while the slot has not yet been formed. The slot is formed in the metallic base body 11, for example, by laser cutting, water cutting, or milling. This takes place in a machining direction B from the peripheral surface 14, here from the end face 16, of the card body 10 or the metallic base body 11. The slot is formed up to the wall of the module opening 17, so that the slot and the module opening 17 communicate or are connected to each other.

[0042] Fig. 4shows a partial view of the end face 16 of the card body 11 or the metallic base body 11 with a slot 18. An entry angle a of the slot 18 is not equal to 90° to the main surface 12 and analogously to the main surface 13.

[0043] In Fig. 4 The slot 18 is designed at a 45° angle throughout. The entry angle a can, for example, be less than or equal to 85° or between 30° and 60°. Depending on the selected side or wall of the slot 18, the entry angle a can be 45° or, as a corresponding supplementary angle, 135°.

[0044] The slot 18 is formed by a serration cut that provides an overlap or overlap between two opposing walls 18a and 18b of the slot 18. This overlap or overlap is in the direction of a surface normal to the main surface 12, or in other words, in the direction of the thickness or height of the card body 10 or base body 11. In the figures, this is the z-direction. The two walls 18a, 18b can run parallel.

[0045] The angles given above allow sufficient overlap or coverage for the usual card body thicknesses of, for example, between 50 µm and 920 µm and usual cutting widths between 40 µm and 80 µm.

[0046] In the Fig. 4In the example shown, which does not fall within the scope of the claims, the thickness or height of the card body 10 or the metallic base body 11 is 400 µm. With the entry angle α of 45°, a visible depth T is approximately 110 µm. The visible depth T is the distance of the wall 18b from the main surface 12, viewed perpendicularly or in the direction of the surface normal of the main surface 12 at the entry point of the wall 18a. This visible depth T can be seen, for example, as a measure of an overlap or coverage.

[0047] The slot 18 with its walls 18a and 18b divides the base body 11 into two regions 11a and 11b, with region 11a located on the side of wall 18a and bounded by it. Similarly, region 11b lies on the side of wall 18b and bounded by it.

[0048] In the area of ​​the slot 18, there is thus an overlap or covering of the two walls 18a and 18b and thus of the two regions 11a and 11b. This overlap or covering is in the direction of the surface normal of the main surface 12. In a section, even a virtual section, in the direction of the surface normal through the base body 11, there is always an intersection point with both walls 18a and 18b and thus both regions 11a and 11b.

[0049] The overlap or overlap of the two walls 18a and 18b, or the two regions 11a and 11b, now blocks the displacement of region 11a over region 11b. This corresponds to a pressure movement on region 11b in the z-direction, i.e., a movement of the two walls 18a and 18b toward each other. Region 11b can only move a small distance, which roughly corresponds to the visible depth T. It then rests against region 11a and is stopped by it. Thus, the obliquely formed slot 18 can prevent an undesired shearing movement of the card body 10 or the base body 11.

[0050] However, if the area 11b is moved away from the area 11a, which is Fig. 4 corresponds to a downward movement in the negative z-direction, no blocking occurs.

[0051] The above considerations of the movement of area 11b apply analogously to area 11a, only with correspondingly reversed movement.

[0052] Fig. 5 shows a partial view of the end face 16 of the card body 10 with a slot 18 which is wedge-shaped between the two main surfaces 12 and 13.

[0053] As in Fig. 4 the angle of incidence a is 45°. In contrast to Fig. 4 the slot 18 is not straight in cross-section, but as a symmetrical wedge cut with two legs 18c and 18d, both of which have the same entry angle a. A wedge tip 18e of the slot 18 lies in a center plane of the card body 10 or the base body 11. Apart from that, the information according to Fig. 4 also for the Fig. 5 illustrated card body 10 or base body 11.

[0054] In contrast to the Fig. 4 In the card body 10 shown, there is a double overlap or covering of the two walls 18a and 18b or the two areas 11a and 11b in the area of ​​the slot 18.

[0055] In a section, even a virtual section, in the direction of the surface normal through the base body 11, there are therefore at least two intersection points with both walls 18a and 18b.

[0056] This quasi double overlap or covering of the two walls 18a and 18b or the two areas 11a and 11b now blocks the displacement of the two areas 11a and 11b in both directions. Thus, the wedge-shaped slot 18 can prevent unwanted shearing movement of the card body 10 or the base body 11 in both directions. The term "both directions" refers to the direction of both surface normals of the main surfaces 12 and 13.

[0057] Fig. 6 shows a partial view of the end face 16 of the card body 10 with a slot 18 which is formed as an asymmetric wedge cut.

[0058] As in Fig. 5the slot 18 is wedge-shaped, but as an asymmetric wedge cut with two legs 18c and 18d, in which the lengths and also the entry angles a of the two legs 18c and 18d of the wedge-shaped slot 18 are different. The wedge tip 18e of the slot 18 is located off-center in the card body 10 or base body 11. Therefore, the above description of the Figures 4 and 5 referred to.

[0059] Here, too, there is a double overlap or overlap of the two walls 18a and 18b, or the two areas 11a and 11b, in the area of ​​the slot 18. In a section, even a virtual section, in the direction of the surface normal through the base body 11, there are thus at least two intersection points with both walls 18a and 18b in some sections.

[0060] This quasi-double overlap or covering of the two walls 18a and 18b or the two areas 11a and 11b blocks the displacement of the two areas 11a and 11b in both directions. Thus, the wedge-shaped slot 18 can prevent unwanted shearing movement of the card body 10 or the base body 11 in both directions. The term "both directions" refers to the direction of both surface normals of both main surfaces 12 and 13.

[0061] Fig. 7 shows a partial view of the end face 16 of the card body 10 with a slot 18, in which an undercut 18f is provided for both legs 18c and 18d in the area of ​​the wedge tip 18e of the slot 18.

[0062] Except for the two undercuts 18f, the slot 18 or the card body 10 or base body 11 is identical to that shown in Fig. 5shown slot 18 or card body 10 or base body 11. Therefore, the above description of the Figs. 4 to 6 to avoid repetition. The two undercuts 18f can also be provided with an asymmetrical slot.

[0063] These undercuts 18f can be formed, for example, by extending the legs 18c, 18d of the wedge-shaped slot 18 beyond the intersection point 18f of the two legs 18c, 18d. The length or depth of the undercuts 18f can, for example, correspond to the cutting width of the slot 18. It is also possible for the undercut 18f of one leg to be so short that it just penetrates the other leg or its wall.

[0064] Fig. 8shows a partial view of the end face 16 of the card body 10 with a slot 18 which is arcuate or, in other words, has a curved course from the main face 12 to the main face 13.

[0065] One wall 18a of the arcuate slot 18 has a convex portion 18g, and an opposite wall 18b of the slot 18 has a concave portion 18h, with the convex portion 18g engaging the concave portion 18h. The two portions 18g and 18h ​​can be aligned such that they run parallel to each other. This can be easily achieved using a tool the width of the slot 18.

[0066] The convex region 18g and the concave region 18h may occupy part or all of the respective wall 18a or 18b.

[0067] The further details, for example regarding the entry angle or the overlap, correspond to those for the Fig. 4 to 6For example, the curved slot 18 can also be asymmetrical.

[0068] Fig. 9 shows a partial view of the front surface 16 of the card body 10 with a slot 18 with two convex and concave areas 18g and 18h. Accordingly, the statements regarding the Fig. 8 also for the card body 10 according to Fig. 9 .

[0069] The card body 10 or base body 11 according to Fig. 9 has two adjacent convex regions 18g along the wall 18a and two adjacent concave regions 18h along the wall 18b, the respective regions interlocking.

[0070] The two convex regions 18g and the two concave regions 18h can be directly adjacent to each other. It is also possible for a neutral region, for example, in the form of a straight line, to be provided between the two respective regions.

[0071] Fig. 10shows a sectional view of a chip card 30 with a card body 10 as previously described and a chip module 31.

[0072] The card body 10 comprises the base body 11, for example in the form of a metallic layer in the form of a core or a layer of a stainless steel alloy with a thickness of 400 µm.

[0073] One main surface 12 or surface of the base body 11 is covered or laminated with a plastic layer 19. An opposite second main surface 13 or surface of the base body 11 is covered or laminated with another plastic layer 20. The two plastic layers 19, 20 can be made of PVC, PET, PE, PET-G, PLA, or PC, for example. The thickness of the entire card body 10 should not exceed the maximum thickness of a chip card body according to ISO 7810. Typically, the thickness of the plastic films is 180 µm each, with a metal layer thickness of 400 µm, resulting in a total chip card body thickness of 760 µm.

[0074] The module opening 17 is formed in the main side or surface of the card body 10. The module opening 17 extends through the entire plastic layer 19, the entire metallic base body 11, and a portion of the plastic layer 20. The module opening 17 is created, for example, by means of a laser cutting or milling process.

[0075] The chip module 31 is arranged in the module opening 17 and is glued there, for example. The chip module 31 comprises a contact surface structure 32 that supports a coil 33. The contact surface structure 32 rests on the plastic layer 19 in an outer region of the module opening 17.

[0076] The chip module 31 further comprises a chip 34, which is secured, for example, in a potting compound on an underside of the contact surface structure 32. The chip 34 is supplied with energy and / or signals via the coil 33. Thus, an electromagnetic field emerging from the metallic base body 11 can be coupled into the coil 33.

[0077] Fig. 11 shows a schematic representation of a method for producing a card body 10 as previously described.

[0078] In a first step 100 of the method for producing a card body 10 for a chip card 30, the metallic base body 11 is provided with two opposite main surfaces 12, 13 and a circumferential surface 14 connecting the two main surfaces 12, 13. A module opening connecting the two main surfaces 12, 13 can already be provided in the main surfaces 12, 13 or can be provided later.

[0079] In a second step 110 of the method, the slot 18 is created on the peripheral surface 14 between the two main surfaces 12, 13, wherein the slot 18 is formed from the peripheral surface 14 to the module opening 17. If the module opening 17 is to be produced in a later manufacturing step, the slot is created up to the corresponding module opening zone where the module opening is to be formed later.

[0080] The tool for creating the slot 18 is directed towards the circumferential surface 14, ideally perpendicular to the circumferential surface 14. For this purpose, the main axis of the tool with which the slot 18 is created is aligned parallel to the main surfaces 12, 13 and the slot is created starting at the circumferential surface 14 in the direction of and up to the module opening 17 or the corresponding zone.

[0081] The slot 18 is formed such that an entry angle a of the slot 18, at least into one main surface 12, is not equal to ninety degrees relative to the main surface 12. The slot 18 is formed entirely between the two main surfaces 12, 13, so that they are connected by the slot 18.

[0082] Optionally, for example, if the slot 18 is cut with a laser, the focus of the tool or laser is readjusted with increasing cutting depth. This allows material removal to always occur at an optimal operating point. The slot 18 is then formed in stages or continuously. It can also be formed to its full depth at the respective processing point.

[0083] According to the above procedure, the Figures 4 to 9illustrated card body 10 or base body 11. Details of the production of the respective card body 10 or base body 11 are described below.

[0084] For the card body 10 or base body 11 according to Fig. 4 a straight cut is made at an entry angle a of the slot 18 into a main surface 12 up to the opposite main surface 13.

[0085] For the card body 10 or base body 11 according to the Figures 5 and 6 will be like for Fig. 4 started until a change in the direction of the tool occurs in an area of ​​the wedge tip 18e to be created, so that the wedge shape is created. For example, a cutting or milling operation begins on the leg 18c at an angle of 45° to the main surface 12. The cut is made in a straight line up to the wedge tip 18e. There, the tool's trajectory is rotated by an angle, for example, 90°, to then form the leg 18d.

[0086] For the card body 10 or base body 11 according to Fig. 7 Undercuts 18f are formed, for example, by extending the legs 18c, 18d of the wedge-shaped slot 18 beyond the intersection point 18f of the two legs 18c, 18d. To do this, the tool extends beyond the wedge tip 18e in the same direction until the undercut 18f is formed. The same procedure is followed for the second leg.

[0087] For the card body 10 or base body 11 according to the Figures 8 and 9 By means of a suitable tool path, one or more convex regions 18g are formed along the wall 18a and one or more concave regions 18h are formed along the wall 18b, the respective convex and concave regions interlocking.

[0088] To form these convex and concave areas, the tool is moved in an arc over the peripheral surface 14. Combinations of convex and concave areas are possible. These areas should interlock, or in other words, overlap, to avoid shearing movements of the card body 10.

[0089] In an optional third step 120 of the method, a plastic layer 19, 20 is applied to each of the main surfaces 12, 13 using an adhesive, wherein the slot 18 is at least partially filled with the adhesive. The inner contour of the slot 18 at least partially prevents the adhesive from leaking out, so that it remains in the slot 18. The adhesive curing in the slot further stabilizes the card body 10 or the chip card 30. If the module opening 17 in the card body 10 is only created after the plastic layers have been applied, the adhesive that has flowed into the slot 18 and dried or cured there prevents chips generated during the creation of the module opening 17 from becoming lodged in the slot 18 and causing an electrical short circuit there.

Claims

1. Method for producing a card body (10) for a chip card (30), comprising the steps of: - providing (100) a metal main body (11) with two opposite main surfaces (12, 13) and a peripheral circumferential surface (14) connecting the two main surfaces (12, 13), wherein a module opening (17) for receiving a chip module (30) is already made in the main body (11) or is yet to be made in a module opening zone, and - producing (200) a slot (18) on the circumferential surface (14) between the two main surfaces (12, 13), wherein the slot (18) is formed from the circumferential surface (14) up to the module opening (17) or up to the module opening zone, and wherein an entry angle (α) of the slot (18) at least into one of the two main surfaces (12) is not equal to ninety degrees with respect to the main surface (12), characterized in that at least a region of the slot (18) is formed in an arched shape from one main side (12) to the other main side (13) so that a first wall (18b) of the slot (18) has a concave region (18h) and an opposite second wall (18a) of the slot (18) has a convex region (18g), wherein the convex region (18g) engages in the concave region (18h).

2. Method for producing a card body (10) according to Claim 1, characterized in that the slot (18) is shaped by a toothed cut providing an overlap between two opposite walls (18a, 18b) of the slot (18).

3. Method for producing a card body (10) according to Claim 1 or 2, characterized in that the slot (18) is cut with a laser and that the focus of the laser is preferably readjusted as the cutting depth increases.

4. Method for producing a card body (10) according to any one of Claims 1 to 3, characterized in that a change of direction is made when producing the slot (18), such that the slot (18) between the two main surfaces (12, 13) is formed in a wedge shape.

5. Method for producing a card body (10) according to any one of Claims 1 to 4, characterized in that a plastic layer (19, 20) is applied to each of the main surfaces (12, 13) by means of an adhesive, wherein the slot (18) is at least partially filled with the adhesive.

6. Method for producing a card body (10) according to Claim 5, characterized in that the module opening (17) is only produced after the plastic layers (19, 20) have been applied.

7. Card body (10) for a chip card (30), having a metal main body (11) with two opposite main surfaces (12, 13) and a peripheral circumferential surface (14) connecting the two main surfaces (12, 13), wherein a module opening (17) for receiving a chip module (30) is already made in the main body or is yet to be made in a module opening zone, and a slot (18) which extends from the circumferential surface (14) of the main body (11) to the module opening (17) or to the module opening zone and which extends between the two main surfaces (12, 13), wherein an entry angle (α) of the slot (18) at least into a main surface (12) is not equal to 90° with respect to the main surface (12), characterized in that a first wall (18b) of the slot (18) has a concave region (18h) and that an opposite second wall (18a) of the slot (18) has a convex region (18g), wherein the convex region (18g) engages in the concave region (18h).

8. Card body (10) according to Claim 7, characterized in that the entry angle (α) is less than or equal to 82°, preferably between 30° and 60°, and most preferably 45°.

9. Card body (10) according to Claim 7 or 8, characterized in that the slot (18) is shaped by a toothed cut providing an overlap between two opposite walls (18a, 18b) of the slot (18).

10. Card body (10) according to any one of Claims 7 to 9, characterized in that the slot (18) between the two main surfaces (12, 13) is formed in a wedge shape.

11. Card body (10) according to Claim 10, characterized in that one or two undercuts (18f) are provided in the region of a wedge tip (18e) of the slot (18).

12. Chip card (30), comprising a card body (10) according to one of Claims 7 to 11 and a chip module (31) at least partially embedded in the module opening (17) of the card body (10).