Fingerprint sensor with improved bezel, and card-shaped data carrier comprising such a fingerprint sensor
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- GIESECKE & DEVRIENT EPAYMENTS GMBH
- Filing Date
- 2024-05-10
- Publication Date
- 2026-05-06
AI Technical Summary
Capacitive fingerprint sensors in card-shaped data carriers face issues with mechanical damage and electromagnetic interference, leading to reduced recognition rates and performance due to a structured bezel design that can crack and induce eddy currents, respectively.
A bezel with non-continuous recesses and severances is designed to enhance mechanical stability and prevent eddy currents, featuring a jagged peripheral edge and strategically placed cuts to maintain electrical connectivity and reduce material stress, while avoiding complete disconnection and eddy current induction.
The solution extends the service life of the fingerprint sensor by reducing crack formation and maintaining functionality, while minimizing electromagnetic interference, thus improving the recognition rate and performance of the sensor.
Smart Images
Figure EP2024062935_02012025_PF_FP_ABST
Abstract
Description
[0001] FINGERPRINT SENSOR WITH IMPROVED BEZEL AND CARD-SHAPED DATA CARRIER WITH SUCH
[0002] FINGERPRINT SENSOR
[0003] Field of the invention
[0004] The present invention relates to a fingerprint sensor and a card-shaped data carrier with an integrated fingerprint sensor. In particular, the invention relates to an improved edge region (bezel) for such an integrated fingerprint sensor.
[0005] Background of the invention
[0006] Card-shaped data storage devices are used in a wide variety of applications today. For example, such data storage devices can be used for cashless payment of goods or services, for personal identification, or for accessing internet-based applications.
[0007] Accordingly, there are, for example, card-shaped data storage devices in the form of chip cards in general, payment cards such as credit cards or debit cards, as well as personal ID or identity cards and access cards. Payment cards in the form of credit cards or debit cards in particular are often dual-interface chip cards (DI chip cards), which can communicate with other devices, such as point-of-sale terminals, both contact-based via a chip element and contactless via near-field communication (NFC, RFID). To authorize payment transactions with such data storage devices, the entry of a PIN is usually required. However, there are also card-shaped data storage devices with an integrated biometric authentication element (e.g., a fingerprint sensor) for authorizing transactions with the data storage device.Different sensor types, in particular optical sensors, E-field sensors, thermal sensors, capacitive sensors, contactless 3D sensors, ultrasonic sensors, etc., can be considered as fingerprint sensors. Due to various disadvantages of individual technologies (such as their height or energy consumption), capacitive fingerprint sensors have now largely become the preferred choice for use in card-shaped data storage devices (such as chip cards). Such a capacitive fingerprint sensor usually comprises a sensor surface and a metallized border (bezel), i.e. a metallized ring that peripherally surrounds the actual sensor surface. The bezel serves to bring the placed finger to a specific electrical potential and is connected to this purpose via and a conductor track on the back inside the card-shaped data storage device to a sensor chip.
[0008] The spatially resolved capacitance change caused by the finger being placed on the skin can be used to detect how far the finger surface is from the respective sensor pixel by measuring the distance of the skin from the area enclosed within the bezel (the actual sensor area consisting of capacitively readable pixels).
[0009] Such a bezel originally consisted of a continuously metallized border around the sensor on its front. However, for aesthetic reasons, among other things, there is a growing trend to replace the solid metal surface of the bezel in fingerprint sensors for chip cards with a non-continuous, less solid surface, with the bezel's electrical connection still being via a through-hole. However, such a structured bezel design presents various difficulties.
[0010] Firstly, the narrower material width of chip cards with fingerprint sensors with a structured bezel can lead to cracks in the metallization at the inner corners of the bezel over the lifespan of chip cards with fingerprint sensors featuring a structured bezel. This could result in the segments of the bezel not connected to the sensor chip via the vertical interconnect access (VIA) being electrically isolated and no longer contributing to the electrical contact of the applied finger. Depending on the position of the finger placed on the fingerprint sensor, this would reduce the recognition rate, meaning the performance of the fingerprint sensor would be undesirably reduced.
[0011] Secondly, such chip cards are often designed as dual-interface chip cards, with an antenna coil in the card body used for wireless communication with an RFID reader. To facilitate operation of the fingerprint sensor, it is often located at the edge of the card body. Since the bezel described above represents a closed, ring-shaped conductor path, eddy currents can be induced by high-frequency alternating electromagnetic fields through the nearby antenna coil when communicating with the RFID reader. This increases the attenuation of the antenna coil and thus impairs performance.
[0012] Description
[0013] Accordingly, it is an object of the present invention to provide a structured metallized border (bezel) for card-shaped data carriers, which is largely resistant to mechanical damage and largely minimizes electromagnetic interference with the antenna coil.
[0014] This object is achieved by the subject matter of the independent claim. Exemplary embodiments emerge from the dependent claims and the following description.
[0015] According to a first aspect, a device is provided comprising a base having a base surface, an input element, and a sensor chip. The input element is received in the base and is accessible from the base surface. The input element comprises an input section and a surrounding metallized border (bezel). The bezel has an outer edge facing away from the input section in the lateral direction and an inner edge facing the input section in the lateral direction. Starting from the outer edge and / or the inner edge, the bezel has a plurality of non-continuous recesses in the lateral direction, such that the outer edge and / or the inner edge defines a serrated surrounding edge. The bezel is electrically connected to the sensor chip via at least one via (Vertical Interconnect Access, VIA), which runs at least partially through the base.The sensor chip is configured to apply an electrical potential to the bezel via the at least one VIA.
[0016] The device comprises an input element on a base that enables functional interaction between a user and the device itself or a higher-level system of the device. For example, if the device is integrated into a card-shaped data carrier, as described below, the input element can enable interaction with a card chip of the card-shaped data carrier (for example, to activate or enable a read operation of the card chip). Such an input element can be, for example, a biometric authentication element, such as a fingerprint sensor or another biometric sensor that is connected to an integrated functional element, such as a card chip.Although the input element is primarily described herein as a capacitive fingerprint sensor, it should be noted that the present disclosure is not limited to such a fingerprint sensor. Rather, the input element may also be any other suitable input element that can benefit from an improved bezel described herein and is constructed in a similar manner. Such input elements may, for example, serve to authorize transactions performed with the card by an authorized user. In the case of a payment card (e.g., a credit card), the input element may, for example, be used to verify authorization to use the card (i.e., to authorize payment transactions) by capturing a user's fingerprint instead of a PIN. In the case of an ID card, the input element may, for example, be used to authorize an online ID function, etc.
[0017] The base can be a flexible base, such as a card body or a film, or a rigid or inflexible base, such as a rigid support element, or any other conceivable base which carries the functional elements of the device, i.e. the input section, the bezel, and the sensor chip. If the device is part of a card-shaped data carrier, the base can, for example, be a card body of the card-shaped data carrier itself or at least a part of the card body. However, in such a case it is also conceivable for the device itself to be arranged on a film or a similar or other element as a base and thus to represent an independent component which can be integrated into the card body, for example by the film (orgenerally the base) is laminated into the card body during the production of the card and is connected accordingly to functional elements of the card-shaped data carrier, such as a card chip.
[0018] The input element itself comprises the input section and the surrounding metallized border (also called a bezel). The input section serves to receive user inputs, for example, when a user places a finger on the input section. For example, in a capacitive fingerprint sensor, which is described in detail below, the input section serves to capture a user's fingerprint. The input section can, for example, be arranged above the sensor chip and be functionally coupled to it so that the sensor chip can process the captured data.
[0019] The bezel surrounds the input section, forming a border around the input section, and is made of a metallic material. However, it is also conceivable for the bezel to be made of another electrically conductive material. The only important thing in this case is that the electrical conductivity is high enough to bring a finger to the desired electrical potential. The bezel and the input section are dimensioned so that both the input section and the bezel are touched during an input process. The bezel serves to bring the user's finger to a defined electrical potential during the input process in order to capture reliable input (for example, to correctly capture a fingerprint with a capacitive fingerprint sensor). For this purpose, the bezel is brought to a defined electrical potential by applying this potential to the bezel via the sensor chip.When the finger then touches the bezel, it is also brought to this electrical potential. The bezel is connected to the sensor chip via a through-hole contact (VIA), which, in a conventional manner, establishes an electrical connection to the sensor chip via corresponding conductor tracks.
[0020] The bezel essentially runs in the form of a band around the input section and has an inner edge and an outer edge. The inner edge faces the input section in the lateral direction, and the outer edge faces away from the input section, so that the input section is surrounded by the bezel.
[0021] The term “lateral direction” as used herein means a direction that is oriented perpendicular to the peripheral edge at the corresponding position around the circumference of the input element. For example, if the input element is rectangular or square, the lateral direction runs perpendicular to the upper and lower peripheral edges, i.e., to the peripheral edges that run horizontally, and the lateral direction runs horizontally at the lateral peripheral edges (which run vertically). At points on the peripheral edge that are neither completely horizontal nor completely vertical, such as in rounded corners of the input element, the lateral direction also runs perpendicular to the peripheral edge at every point. In other words, the lateral direction runs laterally and perpendicular to the peripheral edge around the circumference of the input element, i.e., perpendicular to a tangent to the peripheral edge.It should therefore be understood that the lateral direction is not globally defined as a single direction, but depends on the position around the perimeter of the input element.
[0022] The bezel has a plurality of non-continuous recesses (for example in the form of slots) in the lateral direction on the outer edge, on the inner edge, or on both the outer and inner edges. A recess refers to a type of material cutout, so that the circumferential band defined by the bezel does not define a circumferential, homogeneous surface, but rather defines a jagged edge on the outer edge and / or the inner edge, which is more visually appealing. This also reduces the material required for the bezel. Preferably, the bezel only has such recesses either on the inner edge or on the outer edge, but most preferably only on the outer edge. The at least one via is then, of course, provided at a location on the bezel where no recess is present, in order to electrically connect the bezel to the sensor chip.
[0023] According to one embodiment, the bezel has corner sections that extend at the corners of the input element between the outer edge and the inner edge. The recesses have a smaller lateral extent in at least one of the corner sections than in the remaining sections of the bezel, thus providing structural reinforcement for the bezel.
[0024] Particularly with rectangular or square input elements, but also with differently shaped input elements (e.g., triangular, pentagonal, etc.), mechanical weak points can arise in the corners of the bezel due to the recesses and the resulting narrower material width. This can lead to cracks in the metallization of the bezel at the corners of the inner edge over time due to the frequent bending stress, particularly when the device is used as an integrated fingerprint sensor in card-shaped data storage devices (or in other applications with similar mechanical loads). This would electrically insulate those segments of the bezel that are not connected to the sensor chip via the via (VIA) and would no longer contribute to the electrical contact of the applied finger.Depending on the position of the finger placed on the input element, the recognition rate of capacitive fingerprint sensors would decrease, i.e. the performance of the fingerprint sensor would be undesirably reduced.
[0025] To avoid these problems, it is proposed to provide a smaller lateral extent of the recesses in the corner sections, so that more bezel material is provided in the corner sections. This provides greater mechanical stability in the corner sections, which are more likely to form cracks due to their converging edges. This reduces the likelihood of cracks occurring in the first place and, even if such cracks do occur, extends the time until these cracks have developed to a complete severance at these points, so that the bezel, and thus the input element, remains functional throughout the device's service life.For example, when used in a card-shaped data carrier, the service life of the input element is extended to such an extent that the input element remains functional until the next scheduled replacement of the card-shaped data carrier (for example, in the case of a credit card, until the expiry date).
[0026] In particular, the recesses extending from the areas outside the corner sections to the corner sections can also be designed such that their lateral extent gradually decreases toward the corners, such that the smallest extent of the recesses is present at the extreme points of the corners and increases from there in the circumferential direction outwards. This creates a visually appealing transition and avoids sudden transitions in the mechanical properties, which leads to a further increase in mechanical stability. Any suitable shape for the reinforced corner sections thus formed can be selected.
[0027] According to a further embodiment, the recesses are designed in the form of arbitrarily shaped slots.
[0028] Such slots can be manufactured particularly easily. In particular, the recesses can be provided in the form of wedge-shaped slots or other slots. However, the slots can, in principle, be designed in any conceivable shape and, in particular, do not have to be straight or wedge-shaped.
[0029] According to a further embodiment, the input element is a biometric authentication element.
[0030] Such a biometric authentication element can be used to verify the identity of a user of the device. For example, if the device is part of a card-shaped data carrier in the form of a payment card (such as a credit card or debit card), as described below, the biometric authentication element can be used, for example, to authorize payment transactions.
[0031] The biometric authentication element is preferably a capacitive fingerprint sensor, but may also be any other known or future developed biometric authentication element that benefits from the improved bezel described herein and that enables confirmation of the user's identity.
[0032] According to a further embodiment, the biometric authentication element is a fingerprint sensor.
[0033] According to a further embodiment, the fingerprint sensor is a capacitive fingerprint sensor.
[0034] Such a capacitive fingerprint sensor can generate an image of a fingerprint based on local capacitance changes. An insulator layer is typically located on the fingerprint sensor (or input section). Beneath this layer is an array of many very small capacitor cells arranged on a sensor chip. The insulator layer and the array of capacitor cells then form the input section of the input element (i.e., the capacitive fingerprint sensor) in the form of a sensor surface made up of capacitively readable pixels, which can thus be used to generate an image of the fingerprint. When a finger is placed on the insulator layer, the electrical charge changes. This occurs everywhere, but is particularly pronounced in the areas between the finger grooves.Where there are no grooves (of the fingerprint), the change in capacitance is smaller, because the finger surface does not rest on the corresponding sensor pixels there. This means that by measuring the distance of the skin from the area enclosed within the bezel (i.e., the input section; the actual sensor surface consisting of the capacitively readable pixels), it is possible to detect how far the finger surface is from the corresponding sensor pixel, from which the structure of the fingerprint can be determined. For example, electronics can then convert the data acquired in this way into a digital image of the fingerprint. Due to the way it works, it is necessary, or at least advantageous, especially with such a capacitive fingerprint sensor, if the finger is brought to a defined electrical potential. It should be noted that the structure of the capacitive fingerprint sensor described above (insulating layer, capacitor cells, etc.)) is merely an example, and any other fingerprint sensor with capacitively readable pixels can be used.
[0035] According to a further embodiment, the bezel further comprises at least one cut in the lateral direction, so that the bezel forms a non-continuous circumferential border, so that induced eddy currents in the bezel are prevented.
[0036] A bezel that is completely closed in the circumferential direction represents a ring-shaped, closed conductor structure, even if it has the disclosed slotted shape. In the presence of external alternating electromagnetic fields, eddy currents are induced in such a closed conductor structure, which counteract the external alternating electromagnetic field. In particular, if the device is used, for example, as a capacitive fingerprint sensor in card-shaped data carriers such as credit cards or other chip cards, the input element is typically arranged very close to the edge or in a corner of the card-shaped data carrier to allow a user to easily place a finger on it.At the same time, card-shaped data storage devices such as dual-interface chip cards, which have both a contact-based interface via a card chip attached to the surface of the card-shaped data storage device and a contactless interface with an antenna coil integrated into the card body, require external alternating fields to excite the antenna coil, particularly during contactless reading via the contactless interface. Such an antenna coil is either galvanically connected (i.e. via solder joints) or inductively coupled to the card chip. During a contactless reading process, the antenna coil must supply both the input element and a card chip with electrical energy. However, the closer a metallic structure such as the bezel is to the lines of the antenna coil, the greater the attenuation, i.e. the Q factor of the antenna coil is reduced, thus degrading performance.However, an arrangement, particularly in a card-shaped data carrier (such as a dual-interface chip card), in which the fingerprint sensor is located at an increased distance from the wires of the antenna coil and the antenna coil itself is reduced in size, is technically not feasible, at least not at present, since the largest possible area enclosed by the antenna coil is required in order to supply the input element (such as a capacitive fingerprint sensor) with sufficient electrical energy from the high-frequency field of a card reader.
[0037] To avoid the adverse eddy currents described above, at least one lateral cut is provided. Such a cut can be understood, for example, as meaning that at least one of the recesses is continuous, creating a continuous slot that divides the bezel into two areas that are completely electrically insulated from one another. As a result, the bezel no longer forms a closed, ring-shaped conductor structure, so that the induction of eddy currents in the bezel by the alternating electromagnetic field of a card reader (and the associated adverse effects described above) is largely avoided or at least significantly reduced. Such a cut can, in principle, be provided at any point around the circumference of the bezel. Furthermore, the cut does not have to be at the location of a recess, but can, in principle, be located anywhere on the bezel.
[0038] According to a further embodiment, the at least one cut is arranged on a side of the bezel opposite the at least one VIA.
[0039] Such an arrangement ensures that there are always a maximum of two corners between the via and the cut (in the case of a square input element), reducing the likelihood that cracks developing in the corner sections could completely electrically isolate a section of the bezel from the via, and thus from the sensor chip, which would result in poorer performance of the input element. However, both the via and the cut can, in principle, be located anywhere along the length of the respective side section of the bezel.
[0040] According to a further embodiment, the bezel further comprises at least two cuts. Each two cuts define a segment of the bezel between them.
[0041] This further reduces the induction of eddy currents. For example, a cut can be provided in the middle of each side of the bezel. In such a configuration, however, it should be ensured that each segment of the bezel is electrically connected to the sensor chip, so that a user's finger touching the input element is always electrically connected to the sensor chip via the bezel and thus brought to the desired electrical potential.
[0042] According to a further embodiment, a VIA is provided in each segment of the bezel, which electrically connects the respective segment to the sensor chip.
[0043] Providing such a VIA in each of the segments ensures that each segment is electrically connected to the sensor chip and thus brought to the desired electrical potential. This ensures that a finger placed on the input element is brought to the desired potential regardless of its orientation, how the finger is placed on the input element, and whether the finger touches all segments or only individual ones. The respective VIAs are then connected to the sensor chip on the back, as described above.
[0044] According to a further embodiment, the sensor chip is configured to apply the same electrical potential to each segment of the bezel via the corresponding VIA.
[0045] According to a further embodiment, the base has a greater extension than the input element in at least one direction, and the input element is arranged relative to the base such that the input element is located in a corner of the base. For example, if the device is incorporated into a card-shaped data carrier, as described below, this arrangement enables easy operation of the input element (for example, as a fingerprint sensor) by a user.
[0046] If one or more cuts of the bezel are provided, as described above, the device is also advantageously oriented relative to the base (for example in the form of the card body) such that the cut(s) face(s) at least one of the side edges of the base, thereby ensuring optimal use with best performance over the service life of the device.
[0047] According to a second aspect, a card-shaped data carrier is provided. The card-shaped data carrier comprises a card body and at least one device according to one of the above-described embodiments. The base of the device is at least partially identical to the card body or is integrated into the card body, so that the input element and the bezel are accessible from a card surface of the card body.
[0048] The card-shaped data carrier can comprise a plastic material or a natural material (such as wood), which forms the card body of the card-shaped data carrier. The card body can also be made of recyclable and / or biodegradable materials. The card body can be flat and can also be constructed in multiple layers, which are created in a lamination process during the manufacture of the card body. For example, the card body can have a base structure and a surface layer, i.e., a so-called overlay.
[0049] The card body forms the basis of the device described above, and the card surface of the card-shaped data carrier thus forms the base surface. The input element, such as a capacitive fingerprint sensor, is then accessible to a user from the card surface, allowing the user to place a finger on the input element. All features described above with reference to the device are then also valid for the card-shaped data carrier, with the replacement of the base by the card body and the base surface by the card surface.
[0050] It should be noted, however, that the device may also continue to have an independent base, such as a carrier film or a similar element, which, for example, during the production of the card-shaped data carrier in the lamination process indicated above, can be introduced into a recess of at least the uppermost layer of the card body, connected to the functional elements of the card-shaped data carrier (e.g. a card chip), and laminated in.
[0051] According to one embodiment, the card-shaped data carrier is a chip card with a contactless interface or a dual-interface chip card with a contact-based interface and a contactless interface.
[0052] Such chip cards are particularly suitable as payment cards (credit cards / debit cards).
[0053] According to a third aspect, a use of a card-shaped data carrier according to one of the previously described embodiments as an identification document, identity document, chip card, or payment card is provided.
[0054] Short description of the characters
[0055] Fig. 1 shows a card-shaped data carrier with a device having an input element with a surrounding metallized border (bezel) according to the prior art.
[0056] Fig. 2 shows the device from Fig. 1 with a modified / improved metallized bezel according to the invention. Fig. 3 shows the device from Fig. 2, wherein the bezel has reinforced corner sections for mechanically strengthening the bezel and preventing cracks in the bezel.
[0057] Fig. 4 shows the device from Fig. 3, which additionally has a cut through the bezel in order to prevent or at least reduce induced eddy currents.
[0058] Fig. 5 shows the device from Fig. 4, which is modified compared to Fig. 4 by the lateral arrangement of the via.
[0059] Fig. 6 shows the device from Fig. 2, wherein the bezel has four cuts together with four vias, so that the bezel is divided into subsegments.
[0060] Fig. 7 shows the device from Fig. 4 in the form of a capacitive fingerprint sensor, which is accommodated in a card-shaped data carrier in a first preferred orientation.
[0061] Fig. 8 shows the card-shaped data carrier of Fig. 7, wherein the device is arranged in a second preferred orientation on the card-shaped data carrier.
[0062] Detailed description of exemplary embodiments
[0063] The representations in the figures are schematic and not to scale. Where the same reference symbols are used in different figures in the following description, they refer to identical or similar elements. Identical or similar elements may also be designated by different reference symbols.
[0064] Fig. 1 shows a card-shaped data carrier 200 with a device 100 with a
[0065] Input element 20 according to the prior art. The card-shaped data carrier 200 comprises a card body 210 with a card surface 211, wherein the base of the device 100 is received in the card body 210. The card surface 211 thus also forms a surface of the device 100. The card-shaped data carrier 200 is designed as a dual-interface chip card 200 and comprises a contact-based interface 220 and a contactless interface 50 with an antenna coil 51, which is functionally coupled to a card chip (not shown) (for example, inductively or by soldering points; the connection to the card chip itself is also not shown). The card chip can be arranged directly below the contact-based interface 220, or integrated into the sensor element, or arranged at any other suitable location.
[0066] The input element 20 is a capacitive fingerprint sensor 20 and has an input section 21 and a metallized border 22, also referred to as a bezel 22. The bezel 22 is designed as a circumferential, homogeneous, i.e., continuous, surface made of a metallic material. The bezel 22 is electrically connected via a via 60 (VIA 60) to a sensor chip (not shown) arranged beneath the input section 21. The sensor chip applies an electrical potential to the bezel 22 via the VIA 60. When a user places a finger on the fingerprint sensor 20, and thus on both the input section 21 and the bezel 22, the finger is brought to an electrical potential necessary for the capacitive fingerprint sensor 20.The capacitive fingerprint sensor can then, as described above, recognize a fingerprint of the user and thus, for example, authorize a payment transaction (in the case of a payment card, such as a credit card or debit card), an identification transaction (in the case of an electronic identification document in the form of a chip card), or another transaction depending on the intended use of the card-shaped data carrier 200.
[0067] Fig. 2 shows the device 100 from Fig. 1 with a specially slotted bezel 22. The basic functionality of the device from Fig. 2 corresponds to that of the device 100 from Fig. 1. The bezel 22 has an inner edge 25 and an outer edge 24. Unlike in Fig. 1, a plurality of non-continuous recesses 26 are provided circumferentially around the outer edge 24 of the bezel 22 in the lateral direction 1. The lateral direction 1 is not a globally uniform direction, but differs depending on the position around the circumference of the input element 20 (indicated by eight double arrows). In general, the lateral direction 1 describes at each position a direction perpendicular to the outer edge 24 and the inner edge 25 running parallel thereto, ie in each case perpendicular to a tangent to the outer edge 24. The recesses 26 are not continuous, i.e. they do not represent complete separations of the bezel 22 in the lateral direction 1.The bezel 22 thus continues to form a continuous, metallized border, which is still electrically connected to the sensor chip (not shown) via a VIA 60 and can thus fulfill the same function as the bezel 22 in Fig. 1. However, the outer edge 24 forms a structured, circumferential edge 28, which, on the one hand, saves material and, on the other hand, provides a more appealing visual impression.
[0068] However, due to the reduced material thickness along the lateral direction 1 in the areas of the recesses 26, cracks 2 may occur, which may electrically isolate individual sections of the bezel 22 from the VIA 60 and thus also from the sensor chip. This is particularly the case if more than one such crack 2 occurs. The risk of such cracks 2 exists particularly in the corners 29 of the bezel 22, since this is where the horizontally and vertically running sections of the bezel 22 meet and thus form mechanical weak points. In particular, when used in a card-shaped data carrier 200, as shown in Figs. 1, 7 and 8, such cracks 2 may occur due to the bending stress that frequently occurs there.
[0069] To avoid these problems, Fig. 3 shows a device 100 with an input element 20 with an improved bezel 22.
[0070] Fig. 3 shows a device 100 with an input element 20, the bezel 20 of which is modified compared to the bezel 22 of Fig. 2 by reinforced corner sections 27. In the reinforced corner sections 27, the lateral extent of the recesses 27 is smaller than in the remaining areas of the bezel 22, so that more metallic material of the bezel 22 is present there. This additional material provides, on the one hand, improved mechanical support against bending. On the other hand, cracks 2, should they nevertheless form, take longer to develop far enough to form a complete interruption of the bezel 22 at the location of the crack 2. As a result, the bezel 22, particularly when used in card-shaped data carriers 200, such as a payment card, can survive their service life without becoming inoperable, even if cracks 2 should occur.
[0071] In this case, the recesses 26 can also be designed from areas outside the corner sections 27 towards the corner sections 27, in particular, such that their lateral extent decreases successively towards the corners 29, such that the smallest extent of the recesses 26 is present at the extreme points of the corners 29 and increases from there in the circumferential direction (i.e. in the direction along the outer edge 24) outwards away from the corners 29, so that on the one hand a visually appealing transition is designed and on the other hand sudden transitions in the mechanical properties are avoided, which leads to a further increase in mechanical stability. Any suitable shape of the reinforced corner sections 27 formed in this way can be selected.
[0072] 4 and 5 show a further improvement of the device 100 from Fig. 3, in particular the bezel 22 of the input element 22. In this case, a cut 23 in the lateral direction 1 is provided on a lower horizontally running region of the bezel 22. Such a cut 23 can be provided, for example, in that one of the recesses 26 between the inner edge 25 and the outer edge 24 runs completely through the corresponding section of the bezel 22, as shown in Figs. 4 and 5. However, any other form of cut 23 that completely breaks through the bezel 22 at one point is also conceivable. As a result of the cut 23, the bezel 22 no longer forms a closed, ring-shaped conductor path, so that ring-shaped currents can no longer be induced in the bezel 22 and eddy currents in the bezel 22, which are caused by alternating electromagnetic fields, are at least reduced.Since the sections on both sides of the cut 23 are also still conductively connected to the VIA 60, the entire bezel 22 remains at the desired electrical potential, so that a finger placed on it can be brought to precisely this potential.
[0073] In the embodiments of Figs. 4 and 5, the via 60 (VIA 60) is also located opposite the cut 23. This ensures that only two corners 29 are ever located between the VIA 60 and the cut 23, thus reducing the probability that one or more segments or sections of the bezel 22 will be completely electrically isolated from the VIA 60 and thus the sensor chip by cracks 2 forming in the corners 29 (cf. Fig. 2), which would result in poorer performance of the input element 20 (e.g., fingerprint sensor 20). However, it should be noted that this arrangement, although advantageous, is not mandatory, and the VIA 60 and the cut 23 can, in principle, also be arranged differently relative to one another.
[0074] The design of Fig. 5 differs from the design of Fig. 4 in that the VIA 60 is not arranged centrally in the corresponding section of the bezel 22, but offset laterally therefrom.
[0075] Fig. 6 shows a further embodiment of the device 100 with the input element 20. In this embodiment, no reinforced corner sections 27 are shown. However, it should be noted that the reinforced corner sections 27 of Figs. 3 to 5 as well as 7 and 8 can also be provided here in addition to mechanically reinforce the corners 29. The bezel 22 here has a plurality (four in the illustrated embodiment) cutouts 23, with a cutout 23 provided on each side of the bezel 22. A segment 31 of the bezel 22 is defined between each two of the cutouts 23. The segments 31 are each completely electrically insulated from one another along the circumferential direction. Each of the segments 31 has its own via 60 (VIA 60) to the sensor chip (not shown) on the back, so that each segment 31 is kept at the same electrical potential by the sensor chip.Although the effects of cracks 2 are less severe in this embodiment, the wiring complexity increases due to the need to connect each segment 31 to the sensor chip via its own VIA 60. Figures 7 and 8 show the device 100 of Figure 4, which is incorporated into a card-shaped data carrier 200, similar to the card-shaped data carrier 200 of Figure 1. To avoid repetition, elements corresponding to Figure 1 are not described again herein.
[0076] The input element 20 here is a capacitive fingerprint sensor 20. Due to the type and orientation in which a finger is typically placed on such a fingerprint sensor 20, the orientation of the fingerprint sensor 20 in the card-shaped data carrier 200 is preferably such that the cut 23 in the bezel 22 faces the right card edge (Fig. 7) or the bottom card edge (Fig. 8). This enables use of the card-shaped data carrier 200 with optimal performance over its entire service life (for example, until a payment card is replaced after a predetermined service life), even if the metallization of the bezel 22 should tear completely through in one of the corners 29, since the finger is always placed on the fingerprint sensor 20 such that the bezel 22 is touched on both sides of the cut 23. Although the embodiments shown in Fig.7 and 8 are the preferred orientations of the input element 20 on a card-shaped data carrier 200, it should be noted that, in principle, any other orientation or placement on the card body 210 is also possible. However, the design of connection pads for functionally connecting the device 100 to the card-shaped data carrier 200 (for example, to its card chip 220) must, of course, be adapted to the corresponding orientation.
[0077] Overall, it should be noted that the disclosed device 100 may include both the mechanical reinforcement in the form of the reinforced corner sections 27 and the cut(s) 23, only the mechanical reinforcement in the form of the reinforced corner sections 27, or only the cut(s) 23. Furthermore, it should be noted that, although described primarily with reference to capacitive fingerprint sensors 20, the disclosed design of the bezel 22 may also be used for other input elements 20 that rely on a bezel 22 or another functionally similar component. Furthermore, it should be noted that, although described primarily with reference to use in a card-shaped data carrier 200, the device 100 may also be used in any other suitable application. In particular, objects subject to high bending loads benefit from the disclosed design of the bezel 22.
[0078] List of reference symbols
[0079] 1 lateral direction
[0080] 2 cracks
[0081] 20 input elements, biometric authentication elements, fingerprint sensors
[0082] 21 Input section
[0083] 22 metallized border, bezel
[0084] 23 Severing
[0085] 24 outer edge
[0086] 25 inner edge
[0087] 26 recesses, slots
[0088] 27 corner sections
[0089] 28 structured edge
[0090] 29 corners
[0091] 31 Segment of the bezel
[0092] 50 contactless interface
[0093] 51 Antenna coil
[0094] 60 through-hole plating (VIA)
[0095] 100 device
[0096] 200 card-shaped data carrier, dual-interface chip card
[0097] 210 card body
[0098] 211 Map surface
[0099] 220 contact-based interface
Claims
Patent claims 1. A device (100) comprising: a base with a base surface; an input element (20); and a sensor chip; wherein the input element (20) is received in the base and is accessible from the base surface; wherein the input element (20) comprises an input section (21) and a surrounding metallized border (22), bezel (22); wherein the bezel (22) has an outer edge (24) facing away from the input section (21) in the lateral direction (1) and an inner edge (25) facing the input section (21) in the lateral direction (1); wherein the bezel (22) has, starting from the outer edge (24) and / or the inner edge (25), a plurality of non-continuous recesses (26) in the lateral direction (1), such that the outer edge (24) and / or the inner edge (25) defines a surrounding structured edge (28); wherein the bezel (22) is electrically connected to the sensor chip via at least one via (60), VIA (60);and wherein the sensor chip is configured to apply an electrical potential to the bezel (22) via the at least one VIA (60); 2. Device (100) according to claim 1, wherein the bezel (22) has corner sections (27) which extend at corners (29) of the input element (20) between the outer edge (24) and the inner edge (25); and wherein the recesses (26) in at least one of the corner sections (27) have a smaller lateral extent than in the remaining sections of the bezel (22) and thus provide structural reinforcement of the bezel (22).
3. Device (100) according to one of the preceding claims, wherein the recesses (26) are designed in the form of arbitrarily shaped slots.
4. Device (100) according to one of the preceding claims, wherein the input element (20) is a biometric authentication element (20).
5. The device (100) of claim 4, wherein the biometric authentication element (20) is a fingerprint sensor (20).
6. The device (100) of claim 5, wherein the fingerprint sensor (20) is a capacitive fingerprint sensor (20).
7. Device (100) according to one of the preceding claims, wherein the bezel (22) further comprises at least one cut (23) in the lateral direction (1), so that the bezel (22) forms a non-continuous circumferential border, so that induced eddy currents in the bezel (22) are prevented.
8. Device (100) according to claim 7, wherein the at least one cut (23) is arranged on a side of the bezel (22) opposite the at least one VIA (60).
9. Device (100) according to claim 7 or 8, wherein the bezel (22) has at least two cuts (23); and wherein each two cuts (23) define a segment (31) of the bezel (22) between them.
10. Device (100) according to claim 9, wherein in each segment (31) of the bezel (22) a VIA (60) is provided which electrically connects the respective segment (31) to the sensor chip.
11. The device (100) of claim 10, wherein the sensor chip is configured to apply the same electrical potential to each segment (31) of the bezel (22) via the corresponding VIA (60).
12. A card-shaped data carrier (200), comprising: a card body (210); and at least one device (100) according to any one of the preceding claims; wherein the base of the device (100) is integrated into the card body (210) such that the input element (20) and the bezel (22) are accessible from a card surface (211) of the card body (210).
13. Card-shaped data carrier (200) according to claim 12, wherein the card-shaped data carrier (200) is a chip card (200) with a contactless interface (50) or a dual-interface chip card (200) with a contact-based interface (220) and a contactless interface (50).
14. Use of a card-shaped data carrier (200) according to one of claims 12 or 13 as an identification document, identity document, chip card, access card or payment card.