Various exemplary embodiments relate to a chip card body, to a chip card and to a method for producing a chip card body.
Credit cards have already been used as payment means for more than half a century, cardboard cards having been used as a form of temporary credit card for the purchasing of products and services before the dissemination of plastic cards.
Recently, plastic cards (FIG. 1A represents a conventional plastic chip card 100 in which the chip module 104 has been removed from its reception opening in the chip card body) have encountered competition from metal credit cards, which are being offered by an increasing number of credit card manufacturers. One of the reasons for this is the so-called “plunk factor”, which describes the imposing effect, producible only by metal, which occurs when a metal credit card (with the corresponding noise and metallic gleam) is thrown onto a shop counter. The metal credit card is in this case actually used as a status symbol since metal credit cards were originally offered particularly to wealthy customers. In such cases a noble metal, for example gold or at least a gold coating, as the metal and/or an artistic configuration of the metal card was used, as is represented by way of example for the schematically depicted card in FIG. 2A (upper image). Since then, however, metal credit cards (see, for example, the metal credit card example of FIG. 2A (bottom)) have also been offered to normal customers.
The cards represented in FIG. 2A are currently provided primarily as contact credit cards. This means that data exchange with a chip of the credit card is carried out by means of contacting by contact faces 220 integrated in a chip module, which are configured according to ISO 7816, even if they are possibly configured (as represented in the upper image in FIG. 2A) in such a way that they form a part of an artistic configuration of a card body 106, into which the chip module is inserted.
As an alternative or in addition, contactless data exchange with the chip card chip would be desirable. For contactless data transmission, a corresponding antenna must be connected to the chip card chip. One economical, effective and robust solution for such an antenna is offered for a conventional contactless chip card 100 by so-called coil-on-module technology. This consists essentially of a coil-on-module chip module 104, which comprises a module antenna 110 for inductive coupling to a booster antenna 102 arranged in the chip card body 106 (see FIG. 1A and FIG. 1B). A corresponding functionality is schematically shown in FIG. 1C.
The contactless chip card 100 may have the booster antenna 102 for wireless communication with an external reader 108. The booster antenna 102, as represented in FIG. 1B and FIG. 1C, may have a series resonant circuit which comprises an inductor 102PC, 102Ls1, an (ohmic) resistor (which is for example provided by means of a resistance of the conductive line that forms the antenna), and a capacitor 102Cs. The booster antenna 102 may furthermore have a coupling coil Ls2, 102Ls2 for coupling to the module antenna 110 of the chip module 104. The part of the booster antenna 102 which is used for coupling to the external reader 108 is also referred to as a pickup coil Ls2.
In general, a credit card body made of metal is not very suitable as a body for a contactless credit card with standard antennas laid as a wire because of eddy currents induced in the metal. This is illustrated in FIG. 2A: for example, as represented in FIG. 2B, the credit card body 106 made of metal induces a magnetic field in the opposite direction, which can prevent penetration of magnetic field lines into a magnetic field region of an antenna 102 which is coupled to a chip module 104. Correspondingly, for a chip card read or write device 108 which comprises an antenna 108a, it may be impossible to carry out a read or write process on a chip 105 of the chip module 104.
In the case of antennas 102 according to the prior art, an effect of a metal body 106 is compensated for by means of ferrite, or the antenna 102 is screened from the metal 106 by ferrite. As represented in FIG. 2B (bottom), the ferrite (the “magnetic layer”) leads figuratively speaking to “short circuiting” of the magnetic field lines and thereby causes screening against the metal environment. Such a configuration is used for example in smartphones, for example for a region above the battery, or for example in the case of metal tag devices for near-field communication (NFC).
In general, metal environments and metal surfaces are provided so that they induce eddy currents in the metal which have a magnetic field direction that is opposite to the usual magnetic field direction.
Here, devices and methods are provided which make it possible to provide a metal body or a metal surface as a body of a contactless chip card.