METHOD FOR TESTING A CHIP CARD BODY

Description

[0001] The present invention relates to a method for testing a card body with a metallic core layer for a contactless or dual-interface chip card and to a method for manufacturing a corresponding contactless or dual-interface chip card.

[0002] A contactless or dual-interface smart card comprises a card body, a chip, and an antenna coil coupled to the chip. The antenna coil is located either in a chip module that contains the chip or in the card body itself. A conventional card body is made of thermoplastic material such as PVC, PET, PETG, or ABS, which, however, are sometimes prone to cracking and breakage. For example, a smart card can break due to twisting while in a trouser pocket.

[0003] Compared to conventional card bodies, a card body with a metallic core layer has a longer lifespan due to its relatively greater resistance to torsion. Furthermore, the metallic chip card feels high-quality and robust in terms of its weight. However, integrating the metallic core layer into the card body significantly reduces the contactless functionality of the chip card, thus decreasing the switching distance between the chip card and a card reader. This is because the metal material generally shields electromagnetic waves. The energy transmitted from the card reader to the chip card via electromagnetic waves is partially absorbed and reflected by the metallic core layer.Especially when the chip card is in the changing magnetic field of the card reader, electrons in the metallic core layer move around the chip module in a flow direction, creating an eddy current. This eddy current results in the loss of the transferred energy as heat, a process also known as "absorption," and simultaneously generates an intrinsic magnetic field that opposes changes in the changing magnetic field it created, a process also known as "reflection." Since the eddy current more or less results in the loss of the transferred energy, the remaining energy that the chip module can actually use for contactless communication is correspondingly less than the transferred energy. This means that the switching distance must be reduced due to the eddy current.If the remaining energy is less than a threshold value, for example 2 V, which is crucial for the switching of the chip module, the chip card will not work.

[0004] To counteract the attenuation effect of the metallic core layer, various manufacturing processes are known. US 2016 / 0110639 A1 discloses a chip card comprising, on the one hand, a chip module with a chip and a module antenna, and on the other hand, a metallic card core layer with a cavity for receiving the chip module and a slot or non-conductive strip. The slot or non-conductive strip overlaps the module antenna and extends from the chip module to an outer edge of the metallic card core layer. It serves, in effect, to reduce the aforementioned attenuation effect and increase the reduced switching distance by interrupting the flow of electrons in the metallic card core layer.Since the originally closed eddy current circuit around the chip module is destroyed and no more eddy currents can be generated in the vicinity of the chip module, the energy available for the functionality of the chip module is correspondingly increased. On the one hand, the slot should be as wide as possible to effectively prevent the eddy current, and on the other hand, the slot should be as narrow as possible with regard to the mechanical stability of the chip card. The slot can be cut, for example, using a laser or chemically etched. To increase the stability of the chip card, the slot can be at least partially filled with an electrically non-conductive polymer, epoxy resin, or reinforcing epoxy resin.

[0005] It is crucial that no metal material remains in the slot during cutting or etching. Any remaining metal can cause a partial or even a complete short circuit in the slot's opening, thus reducing its effectiveness. The metallic core layer of the card is typically laminated with at least one additional top layer. During lamination, impurities or a partial or even complete short circuit may occur in the slot. For example, due to high pressure, a seemingly clean, thin slot may be compressed by distortion and create a short circuit. Such chip cards are then non-functional. However, the existing top layer makes the slot inaccessible for inspection. This defect is only discovered during the final testing of the finished chip card.

[0006] US 2020 / 151534 A1 also discloses a chip card comprising a metallic core layer with a cavity for arranging a chip module within the cavity and a slot extending from the cavity to an edge of the metallic core layer. The chip module contains a chip and an antenna coupled to the chip and is arranged within the cavity. A similar chip card is also disclosed in US 2018 / 339503 A1.

[0007] US 2012 / 312879 A1 describes an RFID transponder which, in response to a low-frequency activation signal, sends a high-frequency identification signal, which serves to identify the transponder.

[0008] A method for manufacturing a chip card with a metallic outer layer is disclosed in WO 2019 / 245072 A1.

[0009] Conventional methods for testing the contactless functionality of a contactless or dual-interface smart card with a thermoplastic card body comprise several steps, including an initial step to test the chip module, e.g., according to EP 2779031 B1, and a final step to test the end product, namely the smart card. The initial test of the chip module according to the method in EP 2779031 B1 essentially checks whether the antenna coil of the chip module has a break and / or whether two or more turns of the antenna coil are inadvertently short-circuited. Tests have shown that when testing the end product, it is also possible to indirectly determine whether a partial or complete short circuit has occurred in the slot of the metallic core layer of the card body by retesting the contactless functionality of the smart card.If the contactless function of the chip card is too weak, this is due to a defective slot and the entire chip card will be discarded.

[0010] The object of the present invention is to reduce the manufacturing costs of contactless or dual-interface chip cards.

[0011] This problem is solved by a method with the features of the independent claim. Embodiments and further developments of the invention are specified in the dependent claims.

[0012] A key concept of the present invention is to test the functionality of the card body before the chip module is fixed into the cavity of the card body. A card body exhibiting impurities, a partial short circuit, or a complete short circuit in the slot of its metallic core layer fails the test and is not used for fixing the chip module or for subsequent manufacturing steps. By proactively filtering out all card bodies with a defective metallic core layer, only functional card bodies are fitted with chip modules. Therefore, the only scrap generated is the card bodies with a defective metallic core layer and no longer the card bodies with chip modules. This reduces the costs associated with scrap.

[0013] According to a first aspect of the invention, the method begins with providing a card body with a metallic core layer, wherein the metallic core layer has a cavity for fixing the chip module in a fixing position within the cavity and a slot extending from the cavity to an edge of the card body. The chip module comprises a resonant circuit, which includes a chip, in particular an RFID or NFC chip, and an antenna coil coupled to the chip, in particular an inductively coupled and planar antenna coil with at least one turn. First, the chip module, which is later to become part of the chip card, or another chip module used only for testing, is positioned in or above a fixing position in the cavity, preferably up to a distance of 3 mm vertically above the fixing position. Then, the resonant circuit is tested, i.e., before the chip module is actually fixed in the cavity.

[0014] The chip module is preferably connected to a measuring head of a test fixture and can be positioned in or above the fixation position in the cavity using the measuring head. This makes it possible to work with existing chip module test fixtures, which only need to be adapted so that the chip module can be attached to the measuring head. Alternatively, the card body to be tested can be brought into contact with the measuring head equipped with the chip module.

[0015] To test the functionality of the chip module's resonant circuit, the test device can generate a single current pulse, preferably a DC pulse in the form of a Dirac impulse, which in turn generates a pulsed magnetic field. A steady DC current could thermally overload the chip module's antenna coil. The pulsed magnetic field excites the chip module's resonant circuit without physical contact, causing it to oscillate. Since the chip module's resonant circuit typically includes resistive components that result in energy losses, and the DC pulse in the form of the Dirac impulse does not compensate for these losses, the oscillation is actually a decaying oscillation. This oscillation can correspond to either a current or a voltage in the resonant circuit, and the decay of the oscillation—that is, the decay of the current or the decay of the voltage in the resonant circuit—is detected by the test device.

[0016] The quality factor (Q) can be determined using the test device based on the measured decay of the oscillation. A high Q indicates a slower rate of energy loss in the resonant circuit and a longer decay time. The Q can be determined from two successive decay amplitudes. The smaller the difference between the two successive amplitudes, the higher the Q. To capture the decay amplitudes, the test device can include an integrated oscilloscope that displays the time course of the decaying current or voltage and / or allows individual values ​​to be read.Advantageously, the quality factor Q is compared to a known reference value, which is determined, for example, using a reference chip card or calculated as the average value from the individual quality factors of a large number of chip cards. The reference chip card can also be a contactless or dual-interface chip card with a metallic core layer that has a pre-defined continuous slot opening. Finally, a decision is made as to whether the chip module used for testing, or a suitable alternative, should be fixed in the cavity in the fixation position. For example, the card body is not used if the quality factor Q is lower than the reference value. Otherwise, the chip module used for testing, or a different alternative, is fixed in the cavity in the fixation position. In addition to or instead of the quality factor Q, other parameters, such as a maximum switching distance, can be determined.

[0017] Test results have shown that the distance between the chip module and the fixation position in the cavity influences the decay of the vibration as well as the quality factor Q, and that this influence is linear up to a distance of 3 mm. This means that the functionality of the resonant circuit can be tested relatively easily as long as the chip module is positioned no more than 3 mm relative to the fixation position, preferably vertically above it, i.e., without the chip module needing to be placed in the cavity.

[0018] The slot is preferably produced with a width between 30 µm and 80 µm, particularly preferably between 50 µm and 80 µm. The metallic core layer is then laminated with at least one cover layer, and finally, the cavity is created not only in the metallic core layer but also in the at least one cover layer. The cavity is positioned so that it borders the slot. If the slot does not yet extend to an edge of the metallic core layer, the laminated metallic core layer is trimmed, for example by punching, so that the slot extends to an edge of the metallic core layer. The cover layer can be, for example, a transparent cover layer and / or a layer with a printed pattern and / or any other layer. It can, in particular, incorporate security features.

[0019] Instead of individual metallic core layers, a metallic multi-use sheet can be provided for a plurality of contactless or dual-interface chip cards, wherein the metallic multi-use sheet comprises a corresponding plurality of metallic core layers in which a plurality of slots and a plurality of cavities are generated, such that each metallic core layer of the plurality of metallic core layers of the metallic multi-use sheet comprises at least one slot and one cavity, and in each metallic core layer the at least one slot extends from the corresponding cavity either to an edge of the metallic multi-use sheet or to at least one cutting line along which the metallic core layer is separated from the metallic multi-use sheet in a further step.

[0020] After the metallic multi-use sheet has been laminated with at least one top layer, the corresponding number of cavities can be created not only in the metallic multi-use sheet, but also in the at least one top layer.

[0021] A second aspect of the invention relates to the production of a contactless or dual-interface chip card using the test procedure according to the first aspect of the invention. A key aspect of the second aspect of the invention is to first perform the test procedure and, based on the results, decide whether the chip module used for testing or a different one should be fixed in the cavity. Card bodies that fail the test procedure are not admitted to the manufacturing process according to the second aspect of the invention, while only those card bodies that pass the test procedure proceed to the further manufacturing process. This means that the only rejects from the manufacturing process are card bodies without chip modules, but no more card bodies with chip modules. This reduces the costs associated with rejects.

[0022] The present invention is described below by way of example with reference to the accompanying drawings. These show: Figure 1 a top view of a metallic core layer and a chip module to be inserted into the cavity of the metallic core layer for a contactless or dual-interface chip card; Figure 2 a cross-sectional view of a card body for the contactless or dual-interface chip card, wherein the chip module is connected to a measuring head of a test device; Figure 3 a cross-sectional view of the map body according to Figure 2 , wherein the chip module is positioned in a fixing position in the cavity; Figure 4 Steps of a test procedure for testing the functionality of the card body; Figure 5 a vibration curve that represents the time course of a decaying vibration after excitation of a resonant circuit of the chip module; Figure 6Steps of a manufacturing process including the testing procedure according to Figure 4 ; Figure 7A a top view of a metallic multi-use sheet for a multitude of metallic core layers for a corresponding multitude of contactless or dual-interface chip cards; Figure 7B a section of a metallic core layer made of Figure 7A with a cavity for a chip module and an adjacent slot extending to an edge of the multi-benefit arc; Figure 7C a section of another metallic core layer made of Figure 7A with a cavity for a chip module and an adjacent slot extending to a cutting line; and Figure 8 Steps of a test procedure for testing the functionality of from the multi-user questionnaire according to Figure 7A detached card bodies.

[0023] Figure 1Figure 1 shows a top view of a metallic core layer 10 for a contactless or dual-interface chip card. The metallic core layer 10 includes a cavity 20 for fixing a chip module 30 in a fixing layer 40 (see Figure 1). Figure 3 ) in the cavity 20 and a slot 50 extending from the cavity 20 to an edge 60 of the metallic core layer 10. The slot 50 has a continuous opening 90 along its entire length, in which the two walls 51, 52 of the slot 50 do not contact each other. Alternatively, the slot 50 can extend from the cavity 20 to one of the other three edges 61, 62, 63 of the metallic core layer 10. In contrast to Figure 1 The length, depth, width, shape, direction and angular position between the slot 50 and an edge 60, 61, 62, 63 of the metallic core layer 10, as well as the number of slots, can be changed as required. Figure 1Figure 30 also shows in top view the chip module 30 to be inserted into the cavity, which comprises a resonant circuit with a chip, preferably an RFID or NFC chip, and an antenna coil, preferably an inductively coupled and planar antenna coil with at least one turn.

[0024] Figure 2 shows the cross-sectional view of a card body 100, which contains the metallic core layer 10 according to Figure 1and comprises two cover layers 1 and 2. The upper side 11 of the metallic core layer 10 is laminated with cover layer 1, while the lower side 12 of the metallic core layer 10 is laminated with cover layer 2. Alternatively, only one or both cover layers 1 and 2 may be located on only one of the two sides 1 or 2 of the metallic core layer 10. Depending on the intended use, the number, position, thickness, and material of the cover layers can be varied. Security features and / or individual patterns can also be incorporated on and / or within the cover layers. Figure 2 The chip module 30 also shows this according to Figure 1, which is connected to a measuring head 70 of a test device 200 and is positioned by means of the measuring head 70 in or above the cavity 20 of the metallic core layer 10 and the cover layer 1. From the cavity 20, the slot 50 extends to the edge 60 of the card body 100 and is completely covered on both sides by the two cover layers 1 and 2.

[0025] Figure 3 shows the cross-sectional view of map body 100 according to Figure 2 , where the chip module 30 is positioned here in the fixing position 40 in the cavity 20.

[0026] Figure 4 shows the steps of the procedure for testing the functionality of the card body 100 when the chip module 30 is installed according to Figure 3 in the fixation position 40 in the cavity 20 or at a small distance of no more than 3 mm above it (see Figure 2 ) is positioned. The first three steps S5.1 to S5.3 according to Figure 4 essentially correspond to Figures 1 to 3That is, first, the card body 100 with the metallic core layer 10 and the chip module 30 used for testing, or another chip module 30, are provided (S5.1). Then, the provided chip module 30 is connected to the measuring head 70 of the test device 200 (S5.2). Next, the connected chip module 30 is positioned in or above the fixing position 40 of the cavity 20 of the card body 100 (S5.3). In steps S5.4 to S5.6, the resonant circuit of the chip module 30 positioned in this way is excited (S5.4), and the oscillation generated by the excitation is recorded by means of the test device 200 (S5.5). The test device 200 can include an oscilloscope for this purpose, which can display a corresponding oscillation curve showing the time course of the decaying current or voltage and / or from which the individual values ​​of the current or voltage can be read. Finally, in step S5.6, a quality Q is determined and compared with a reference value R.

[0027] Figure 5Figure 1 shows the oscillation curve displayed by the oscilloscope. The horizontal axis X and the vertical axis Y of the oscillation curve correspond to time t and the current I or voltage U of the resonant circuit of chip module 30, respectively. As already mentioned, the recorded oscillation is indeed a decaying oscillation. This means that over time t, the current I or the voltage U of the resonant circuit exhibits a general downward trend, and the oscillation amplitude An+1 of a subsequent phase is always smaller than the oscillation amplitude An of a previous phase. The initial and maximum oscillation amplitude A0 of the decaying oscillation represents the maximum current or voltage of the resonant circuit when the resonant circuit of chip module 30 begins to oscillate. The quality factor Q can be determined, for example, from the difference D between two successive oscillation amplitudes An and An+1 from two successive phases.

[0028] Figure 6 concerns the preparation of the metallic core layer 10 of the card body 100 according to Figure 1 and 2First, the metallic core layer 10 is provided (S1), in which at least the slot 50 is created, extending to the edge 60, 61, 62, 63 of the metallic core layer 10 (S2). The metallic core layer 10 is laminated with at least one of the two cover layers 1, 2 (S3). Subsequently, the cavity 20 is created in the metallic core layer 10 and in at least one of the cover layers 1, 2 (S4). If no cover layers 1, 2 are laminated with the metallic core layer 10, the cavity 20 is created only in the metallic core layer 10 (S3', S4). The cavity 20 is created such that it adjoins the at least one slot 50. If the slot 50 does not extend to the edge 60, 61, 62, 63 of the metallic core layer 10, the card body 100 is trimmed so that at least one slot 50 extends to the edge 60, 61, 62, 63 of the metallic core layer 10 (S4.1). Then steps S5.1 to S5.6 according to the test procedure according to . Figure 4 This is carried out. As a result, the quality Q is either less than the reference value R and the card body is reject, as described in step S 6a of the Figure 6 shown, or the quality factor Q is at least as large as the reference value R and the chip module 30 used for testing or another chip module 30 is fixed in the fixing position 40 in the cavity 20, as in step 6b of the Figure 6 shown.

[0029] Figure 7AFigure 1 shows a top view of a metallic multi-use sheet 80 with a plurality of metallic core layers 10A, 10B for a corresponding plurality of contactless or dual-interface chip cards. Each metallic core layer 10 of the plurality of metallic core layers 10A, 10B comprises at least one slot 50 and one cavity 20. The multi-use sheet 80 has a quadrilateral shape with two opposing edges 82, 83 and 81, 84. Furthermore, the multi-use sheet 80 has a plurality of cutting lines 90 along which the plurality of metallic core layers 10A, 10B are cut out of the multi-use sheet 80. The cutting lines 90, which are either parallel to the edges 82, 83 of the multi-use sheet 80 or parallel to the edges 81, 84 of the multi-use sheet 80, can be visible and / or virtual lines. In contrast to Figure 7A The number of multiple metallic core layers 10A, 10B can be changed as needed.

[0030] The Figures 7B and 7C Figures A and B show sections A and B, respectively, of two different metallic core layers 10A and 10B of the multi-use sheet 80, the first metallic core layer 10A having its slot 50 adjacent to one of the edges 81, 82, 83, 84 of the multi-use sheet 80, while the second metallic core layer 10B does not have its slot 50 adjacent to one of the edges 81, 82, 83, 84, but instead to one of the cut lines 90 of the multi-use sheet 80.

[0031] Figure 8 shows a procedure for testing the functionality of items from the multi-user form 80 according to Figure 7ASeparated card bodies 100. First, the metallic multi-use sheet 80 with the plurality of metallic core layers 10A, 10B (S1') is provided, and then a corresponding plurality of slots 50 is created in the multi-use sheet 80 (S2'). The metallic multi-use sheet 80 can be laminated with at least one cover layer 1, 2 (S3'), as previously described using a single card body 100, and then a corresponding plurality of cavities 20 is created in at least one of the cover layers 1, 2 and in the metallic multi-use sheet 80 (S4'). If no cover layers 1, 2 are laminated with the metallic multi-use sheet 80, the plurality of cavities 20 is created only in the multi-use sheet 80 (S3", S4').Preferably, each metallic core layer 10 of the plurality of metallic core layers 10A, 10B of the metallic multi-use sheet 80 has at least one slot 50 and a cavity 20, which are produced such that the slot 50 extends from the cavity 20 to either an edge 81, 82, 83, 84 of the metallic multi-use sheet 80, as shown in . Figure 7B shown, or to a cutting line 90 of the metallic multi-use arc 80, as shown in Figure 7C shown, extends. Ultimately, steps S5.1 to S5.6 are carried out according to Figure 4 The procedure was carried out on each card body 100 that was separated from the multi-use sheet 80.

Claims

1. Method for testing a card body (100) with a metallic core layer (10) for a contactless or a dual-interface chip card, comprising the steps: providing the metallic core layer (10) with a cavity (20) for fixing a chip module (30) in a fixing position (40) in the cavity (20) and with at least one slit (50) that extends from the cavity (20) to an edge (60, 61, 62, 63) of the metallic core layer (10); providing the or a chip module (30) with an oscillating circuit, which comprises a chip and an antenna coil coupled to the chip; positioning the provided chip module (30) in the cavity (20) in or above the fixing position (40); and testing the oscillating circuit of the positioned chip module (30) before fixing the chip module (30) in the cavity (20), wherein the chip module (30) is positioned above the fixing position (40) up to a distance of 3 mm relative to the fixing position (40).

2. Method according to claim 1, wherein the step of positioning comprises the following sub-step: connecting the chip module (30) to a probe (70) of a test device (200).

3. Method according to claim 2, wherein the chip module (30) is positioned during the step of positioning by means of the probe (70).

4. Method according to one of claims 1 to 3, wherein the step of testing comprises the following sub-steps: exciting the oscillating circuit by means of the test device (200); and detecting an oscillation of the oscillating circuit generated by the exciting.

5. Method according to claim 4, wherein the step of exciting is performed by inductive excitation by means of a pulsed magnetic field.

6. Method according to claim 5, wherein the pulsed magnetic field is generated by a single current pulse, preferably by a direct current pulse in the form of a Dirac impulse.

7. Method according to one of claims 4 to 6, wherein during the step of detecting, a decay of the oscillation is detected.

8. Method according to claim 7, wherein the step of detecting comprises the following sub-steps: determining a quality factor Q on the basis of the decay of the oscillation and preferably comparing the quality factor Q with a reference value.

9. Method according to one of claims 1 to 8, wherein the step of providing the metallic core layer (10) comprises the sub-steps: providing the metallic core layer (10); generating the at least one slit (50) in the metallic core layer (10); laminating the metallic core layer (10) with at least one cover layer (1, 2); generating the cavity (20) in the at least one cover layer (1, 2) and the metallic core layer (10), so that the at least one slit (50) adjoins the cavity (20); and if the at least one slit (50) does not extend to an edge (60, 61, 62, 63) of the metallic core layer (10), trimming the laminated metallic core layer (10) such that the at least one slit (50) extends to an edge (60, 61, 62, 63) of the metallic core layer (10).

10. Method according to one of claims 1 to 8, wherein the step of providing the metallic core layer (10) comprises the sub-steps: providing a metallic multiple-use sheet (80) for a plurality of contactless or dual-interface chip cards, wherein the metallic multiple-use sheet (80) comprises a corresponding plurality of metallic core layers; generating a plurality of slits in the metallic multiple-use sheet (80), so that each metallic core layer (10) of the plurality of metallic core layers of the metallic multiple-use sheet (80) comprises at least one slit (50); generating a plurality of cavities in the metallic multiple-use sheet (80) for fixing a corresponding plurality of chip modules therein, wherein each metallic core layer (10) of the plurality of metallic core layers of the metallic multiple-use sheet (80) comprises a cavity (20), and in each metallic core layer (10) the at least one slit (50) extends from the corresponding cavity (20) either to an edge (81, 82, 83, 84) of the metallic multiple-use sheet (80) or to at least one cutting line (90) along which the metallic core layer will be separated from the metallic multiple-use sheet (80); and separating the plurality of metallic core layers from the metallic multiple-use sheet (80).

11. Method according to claim 10, wherein the step of providing the metallic core layer (10) comprises the further sub-steps: laminating the metallic multiple-use sheet (80) with at least one cover layer; generating a plurality of cavities in the at least one cover layer and the metallic multiple-use sheet (80) for fixing a corresponding plurality of chip modules therein.

12. Method for manufacturing a contactless or a dual-interface chip card, comprising the following steps: carrying out the method according to one of claims 1 to 11; and subsequently fixing the or a chip module (30) in the fixing position (40) in the cavity (20).

13. Method according to one of claims 1 to 12, wherein the antenna coil is an inductively coupling antenna coil, preferably with at least one winding.

14. Method according to one of claims 1 to 13, wherein the chip is an RFID or an NFC chip.