CHIP CARD

Description

[0001] The invention relates to a chip card and a method for its manufacture. In particular, the invention relates to a so-called metal card.

[0002] To increase the exclusivity of chip cards for so-called prime users, so-called metal cards are offered, usually in the standard ID-1 format according to the international standard ISO 7810. However, the present invention is not limited to metal cards of this format. Solid metal cards, hybrid metal cards with one metallic side and one plastic side, and metal cards coated or printed on one or both sides with plastic or lacquer are known.

[0003] As long as such cards are equipped solely for contact-based communication with a chip module whose contact surfaces are located on the surface of the metal layer or another external layer, communication with metal cards is unproblematic. However, in the case of chip cards equipped with a transponder coil for inductive coupling, which can therefore only or also (dual-interface card) be operated contactlessly, the metal layer can interfere with or completely prevent communication. For example, a two-layer dual-interface chip card with a metal layer and a plastic layer is known from WO 2016 / 016251 A1. The transponder coil arranged between the metal layer and the plastic layer is shielded against interfering capacitive influences of the metal layer by a ferrite layer arranged between the coil and the metal layer.However, RFID transmission only works in one direction, as transmission on the other side of the card is prevented by the metal layer.

[0004] A similar card is known from WO 2014 / 113765 A1, but in this case, the chip module embedded in the metal surface is a dual-interface module, meaning the chip module itself has a small transponder antenna, allowing communication from the metal side as well. Although the transponder coil of the dual-interface chip module is coupled to a larger coil on the back of the chip card, which acts as a so-called booster antenna, the voltage induced from the front of the card is low due to the small diameter of the transponder coil in the dual-interface chip module. The same applies to the all-metal card known from WO 2018 / 132404 A1, in which a transponder coil with a chip is arranged in a perforation in the metal card and can therefore receive RFID signals from both sides.

[0005] A multi-layered metal chip card with a large-diameter transponder is known from WO2017 / 007468 A1. Here, the metal layer is provided only as a metal inlay, surrounded on its perimeter by a plastic frame in which the transponder coil is embedded. With this card, RFID signals can also be received from all sides of the metal card, but this design does not allow the metal layer to extend across the entire surface of the card, i.e., from edge to edge.

[0006] EP 1411 465 A1 discloses a smart card comprising a substrate on which an antenna is mounted. The antenna is electrically connected to a chip module to enable contactless or contact-based electrical communication with a terminal. The smart card also includes a layer with a label and a magnetic stripe. Each of the outer surfaces of the smart card has a protective layer.

[0007] US 6,631,847 B1 describes a chip card with an antenna coil manufactured from a metal sheet by stamping or etching. The antenna is electrically connected to a chip module. Furthermore, each turn of the antenna has a curved section that bends outward and / or inward relative to the plane of the antenna. Thus, the antenna is connected to the chip module in such a way that the antenna turns run beneath the chip module between the connection points of the chip module and the antenna.

[0008] US 2006 / 0187063 A1 describes a method for the selective removal of metal from a metallized substrate (e.g., a metallized polymer film). In this method, the metallized surface is selectively exposed to a demetallizing (i.e., oxidizing) chemical solution. The metallized layer can be selectively exposed to the demetallizing solution using a flexographic printing process in which printing rollers are used to apply the demetallizing solution to the metallized surface.

[0009] WO 2009 / 142656 A1 describes a method for manufacturing a transaction card, comprising cutting a first metal sheet to produce a card body, cutting a second metal sheet to produce a backing, applying an adhesive to the backing and bonding the backing to the card body.

[0010] The object of the present invention is to provide a metal chip card that can receive radio signals with high signal yield from both sides and that can also be designed as a full-surface metal card.

[0011] This problem is solved by a chip card and a method for manufacturing the same, comprising the features of the independent claims. Advantageous embodiments and further developments are specified in dependent claims.

[0012] According to one aspect, the chip card comprises a card body consisting of one or more layers, which in any case includes a self-supporting metal layer. This metal layer can extend across the entire chip card to all its edges, but this is not mandatory. The chip card has an integrated circuit or chip, preferably in the form of a chip module embedded in the chip card, as well as a transponder coil coupled to the chip. The special feature is that the windings of the transponder coil are formed by the metal layer itself. The spaces between the windings are filled with insulating material.

[0013] "Self-supporting" in the context of the metal layer means that it is not a printed metal layer. Transponder coils printed with metallic ink are well-known examples of prior art. Rather, the self-supporting metal layer is a foil or sheet made of a metal, specifically a non-corrosive metal, which is intended to give the card added value.

[0014] The insulating material in the spaces between the transponder coil is intended to shield the windings from capacitive coupling. Ferrite, for example, is a suitable material for this purpose.

[0015] If the metal layer is on the outside and forms one of the main surfaces of the card body, it is preferably completely covered with an insulating layer to prevent coupling between a user's fingers and the windings of the transponder coil. This would otherwise interfere with the transponder coil's resonant circuit and prevent signal transmission. If it is a solid metal card where the entire card body is formed by the metal layer or multiple metal layers, the metal layer or layers on both main surfaces of the chip card can be completely covered with such an insulating layer.

[0016] In particular, the metal layer can be painted, printed or coated with a film, the coating preferably being transparent on at least one side to visually enhance the exclusive effect of the metallic surface for the viewer.

[0017] Accordingly, the metal layer, or in the case of several superimposed metal layers, the group of metal layers, can have a total thickness that is only 25% or more, preferably at least 50%, and particularly preferably at least 75% of the thickness of the card body. Particularly preferably, the card body is formed entirely by the at least one metal layer. Accordingly, the total thickness of the metal layer or metal layers in the case of an ID-1 format chip card is between 0.2 and 0.76 mm.

[0018] The windings of the transponder coil preferably run along the outer edge of the chip card in an outer region to maximize the area enclosed by the coil, thus maximizing the voltage induced in the card by an external magnetic field. It is particularly effective if the windings of the transponder coil have a section running along the edge of the chip card; that is, the edge of the chip card or the outer edge of the metal layer defines the outermost winding of the transponder coil. This allows the coil windings to be arranged with maximum diameter. For all embodiments of the invention, the widths of the windings formed by the metal layer and the spaces between the windings filled with insulating material are adjusted so that the transponder coil exhibits the desired resonant frequency.A typical resonant frequency for RFID transponder coils in chip cards is 13.56 MHz for a transponder coil with 3 to 10 turns.

[0019] As mentioned previously, the metal layer is integrated into the chip card primarily for aesthetic reasons and should be visible to the viewer from at least one side, preferably both sides. This also means that the spaces between the windings, filled with insulating material, may be visible to the viewer.

[0020] In this respect, it can be advantageous if the insulating material does not differ visually from the metal, or does not differ significantly.

[0021] However, if the insulating material in the spaces is visually noticeable, this effect can be aesthetically incorporated by making the windings of the transponder coil appear like nested frames. For this purpose, the windings advantageously run parallel to each other and parallel to the outer edge of the chip card, preferably over the entire circumference of the card.

[0022] To ensure this uniform visual appearance, it is advantageous to position a chip module within the chip card in such a way that any discontinuities in the coil windings are concealed. Specifically, the chip module is preferably positioned above the windings of the transponder coil such that, when viewing the chip card from above, only those sections of the transponder coil windings are visible in the area of ​​the chip module that run parallel to the nearest outer edge of the metal layer and thus parallel to the nearest edge of the chip card. Further along the windings, these sections lie, as mentioned previously, parallel to each other and parallel to the edge of the chip card, creating the impression of nested frames.

[0023] The aforementioned arrangement of the chip module is problematic with regard to the coil running along the edge of the chip card, because this outer coil does not, of course, complete a full circuit (which would cause a short circuit), but is separated from the next adjacent coil at one point by a slot extending to the outer edge of the chip card. Due to standards, the contact surfaces of the chip module for contact-based data transmission do not extend to the edge of the chip card, so this slot remains visible and could be distracting. An alternative design of the transponder coil, to avoid this distracting slot, involves the outer transponder coil not running along the edge of the chip card, but at a distance from it. This makes it possible to conceal all discontinuities in the coil's windings by appropriately positioning the chip module.

[0024] In a further development process, a central area of ​​the metal layer can be omitted and filled with plastic. This is the area enclosed by the windings of the transponder coil. This central area can be equipped with special security features. Furthermore, the surface of the metal layer, with or without the omitted central area, can be textured with elements such as logos, patterns, and / or alphanumeric characters, for example, by laser engraving, milling, or engraving.

[0025] The invention is explained below by way of example with reference to the accompanying drawings. These show: Fig. 1. a chip card according to an embodiment of the invention, Fig. 2. schematically a first variant for the relative arrangement of chip module and coil windings, Fig. 3A. a second variant for the relative arrangement of chip module and coil windings, Fig. 3B. the arrangement according to Fig. 3A in cross-section, Fig. 4 the first variant according to Fig. 2 with a die-cut central area and Fig. 5 the second variant according to Fig. 3A with a cut-out central area.

[0026] Fig. 1 Figure 1 shows an embodiment of a metal chip card 1 in a top view. The metallic surface of the metal layer 2 is visible to the viewer. The metal layer 2 extends over the entire surface of the chip card 1, except for the area of ​​the chip card 1 into which a chip module 3 is integrated and whose contact surfaces form part of the surface of the chip card 1. Outside the contact surfaces of the chip module 3, the metallic surface of the metal layer 2 is coated with a transparent lacquer. It can be printed instead of or in addition to this coating, and / or textures can be incorporated into the metallic surface, such as the exemplary texture "MUSTERMANN".

[0027] In metal layer 2 there is a structure that is not visible here and which relates to the following Figuren 2 and 3 more precisely described transponder coil 4 integrated, and which is in the Figuren 2 and 3 The spaces 5a–5c between the windings 4a and 4b of the transponder coil 4, which are also shown in more detail, are filled with insulating material. However, because the insulating material has a very similar appearance to the metal layer 2, the transponder coil 4 is hardly noticeable when viewing the chip card 1 from above and is therefore not shown in the illustration according to Fig. 1 not visible.

[0028] Fig. 2 Figure 1 schematically shows the metal layer 2 in a top view such that three turns 4a, 4b, 4c of the transponder coil 4 and the spaces 5a, 5b between turns 4a to 4c, as well as a further space 5c that separates the innermost turn 4c from a central area 6 of the metal layer 2, are visible. The outermost turn 4a runs along the outer edge 7 of the metal layer 2 and thus along the edge of the chip card 1. Fig. 1 This is because, in the embodiment described here, the metal layer 2 extends over the entire chip card 1. However, this is by no means mandatory. The metal layer 2 could just as easily be an inlay within the chip card 1 such that it does not extend to the edge of the chip card 1.

[0029] Chip module 3 is positioned above the windings of the transponder coil in such a way that the Fig. 2 The discontinuities in the windings occurring in the left area of ​​metal layer 2 are concealed by the chip module 3. When viewing the chip card 1 from above onto the chip module 3, only sections of windings 4a to 4c are visible, which run parallel to the nearest outer edge 7a of metal layer 2.

[0030] The two ends of the transponder coil 4, formed by the turns 4a to 4c, are electrically connected to the chip module 3 from below. A slot 9 extends between the coil end of the outer turn 4a and the middle turn 4b to the outer edge 7a of the metal layer 2, and is not covered by the chip module 3. Fig. 3A Figure 2 shows a second variant for the design of the transponder coil 4, in which both ends of the transponder coil 4 are located under the chip module 3. Here, the outer winding 4a does not run directly along the outer edge 7 of the metal layer 2, but the entire transponder coil 4 is slightly offset inwards. Accordingly, a further gap 5d is created between the outer winding 4a and an outer area 6a of the metal layer 2, which is filled with insulating material in the same way as the gap 5c that separates the central area 6 of the metal layer 2 from the inner winding 4c. Fig. 3A As can be seen, this arrangement can be designed in such a way that no slot filled with insulating material leads to the outer edge 7 of the metal layer 2, unlike in the first variant described above according to Fig. 2 .

[0031] Fig. 3B schematically shows the arrangement according to Fig. 3A in cross-section. It is particularly evident that this is a metal layer 2 for a solid metal card, where the card body is formed solely by the metal layer 2. The diagram also schematically illustrates how the chip module 3 is inserted into a cavity of the metal layer 2. Alternatively, the metal layer 2 can be formed by several metal layers, and one or more of these metal layers can be combined with further layers, especially plastic layers, which can be transparent and / or opaque, to form a multilayered card body.

[0032] Indicated in Fig. 3B Protective layers 8a and 8b, preferably transparent or translucent, are applied to the opposing main surfaces of the metal layer 2. One or both of the protective layers 8a, 8b can be replaced by a printing layer and / or a laminated plastic film. These can also be transparent or translucent, or at least one layer can optionally be completely opaque. With respect to the metal layer, the protective layers 8a, 8b also function as insulating layers, preventing detuning of the resonant circuit by contact.

[0033] Fig. 4 The metal layer 2 shows how in Fig. 2 , however, the central area 6 is punched out and replaced by a plastic filling 6'. Fig. 5 The metal layer 2 is shown accordingly, as in Fig. 3A shown, in which the central area 6 of the metal layer 2 is also left out and filled with plastic 6'.

[0034] Metal cards according to the above embodiments are RFID-enabled on both sides.

Claims

1. Chip card (1) comprising - a card body consisting of one or more layers, of which at least one layer is a metal layer (2), - an integrated circuit (3) and - a transponder coil (4) coupled with the integrated circuit, the transponder coil (4) having windings (4a, 4b, 4c) and interstices (5a, 5b) between the windings (4a, 4b, 4c), wherein the windings (4a, 4b, 4c) of the transponder coil (4) are formed by the at least one metal layer (2), the interstices (5a, 5b) between the windings (4a, 4b, 4c) being filled with insulating material, characterized in that the card body possesses two mutually opposite main faces, and with at least one of the main faces being formed by the at least one metal layer (2) and being covered over its full area with a transparent or translucent top layer (8a) which prevents coupling between the fingers of a user and the windings (4a, 4b, 4c) of the transponder coil (4).

2. Chip card according to Claim 1, wherein the insulating material is ferrite.

3. Chip card according to either of Claims 1 and 2, wherein the at least one metal layer (2) is varnished, printed or coated with a foil.

4. Chip card according to any of Claims 1 to 3, wherein texture elements are incorporated into the surface of the at least one metal layer.

5. Chip card according to any of Claims 1 to 4, wherein the card body possesses a thickness and the at least one metal layer (2) overall possesses a total thickness, the total thickness of the at least one metal layer (2) being at least 25%, preferably at least 50%, more preferably at least 75% of the thickness of the card body.

6. Chip card according to Claim 5, wherein the total thickness of the at least one metal layer (2) is in a range of 0.2 and 0.76 mm.

7. Chip card according to any of Claims 1 to 6, wherein the card body is formed entirely by the at least one metal layer (2).

8. Chip card according to any of Claims 1 to 7, wherein the windings (4a, 4b, 4c) of the transponder coil (4) have a winding (4a) running along an outer edge (7) of the metal layer (2).

9. Chip card according to any of Claims 1 to 7, wherein the windings (4a, 4b, 4c) of the transponder coil (4) comprise an outer winding (4a) which runs at a distance from an outer edge (7) of the metal layer (2).

10. Chip card according to any of Claims 1 to 9, wherein a chip module (3) is arranged over the windings (3a, 3b, 3c) of the transponder coil in such a way that on viewing of the chip card (1) from above, in the region of the chip module (3), portions of the windings (4a, 4b, 4c) of the transponder coil (4) that are visible are exclusively those which run parallel to a respectively nearest outer edge (7a) of the metal layer (2).

11. Chip card according to any of Claims 1 to 10, wherein the chip module (3) comprises the integrated circuit and contact faces for contact data transmission.

12. Chip card according to any of Claims 1 to 11, wherein a central region (6) of the at least one metal layer (2) is recessed and filled with plastic (6').

13. Method for producing a chip card according to any of Claims 1 to 12, wherein the windings (4a, 4b, 4c) of the transponder coil (4) are generated in the at least one metal layer (2) by removal of material in a region corresponding to the interstices (5a, 5b) between the windings (4a, 4b, 4c), this region being subsequently filled with the insulating material, the card body possessing two mutually opposite main faces, and at least one of the main faces being formed by the at least one metal layer (2) and being covered over its full area with a transparent or translucent top layer (8a) which prevents coupling between the fingers of a user and the windings (4a, 4b, 4c) of the transponder coil (4).

14. Method according to Claim 13, wherein a central region (6) of the at least one metal layer (2) is removed and filled with plastic (6').