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EP-4736067-A1 - FINGERPRINT SENSOR WITH IMPROVED BEZEL, AND CARD-SHAPED DATA CARRIER COMPRISING SUCH A FINGERPRINT SENSOR

EP4736067A1EP 4736067 A1EP4736067 A1EP 4736067A1EP-4736067-A1

Abstract

The invention relates to an apparatus (100) comprising a base having a base surface, an input element (20) and a sensor chip. The input element (20) is received in the base and is accessible from the base surface. The input element (20) comprises an input section (21) and a metallized peripheral border (bezel) (22). The bezel (22) comprises an outer edge (24) that faces away from the input section (21) in the lateral direction (1) and an inner edge (25) that faces the input section (21) in the lateral direction (1). The bezel (22) comprises a multiplicity of discontinuous recesses (26) from the outer edge (24) and/or the inner edge (25) in the lateral direction (1), with the result that the outer edge (24) and/or the inner edge (25) defines a peripheral structural edge. The bezel (22) is electrically connected to the sensor chip by way of at least one plated-through-hole (VIA) (60). The sensor chip is configured to apply an electrical potential to the bezel (22) by way of the at least one VIA (60). The invention also relates to a card-shaped data carrier (200) comprising an integrated apparatus (100) such as this, the base of the apparatus (100) being integrated in the card body (210).

Inventors

  • KLUGE, STEFAN

Assignees

  • Giesecke+Devrient ePayments GmbH

Dates

Publication Date
20260506
Application Date
20240510

Claims (14)

  1. 1. 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 a plurality of non-continuous recesses (26) in the lateral direction (1) starting from the outer edge (24) and/or the inner edge (25), so 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. 2. Device (100) according to claim 1, wherein the bezel (22) has corner sections (27) which run 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. 3. Device (100) according to one of the preceding claims, wherein the recesses (26) are designed in the form of arbitrarily shaped slots.
  4. 4. Device (100) according to one of the preceding claims, wherein the input element (20) is a biometric authentication element (20).
  5. 5. The device (100) of claim 4, wherein the biometric authentication element (20) is a fingerprint sensor (20).
  6. 6. The device (100) of claim 5, wherein the fingerprint sensor (20) is a capacitive fingerprint sensor (20).
  7. 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 peripheral border, so that induced eddy currents in the bezel (22) are prevented.
  8. 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. 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. 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. 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. 12. Card-shaped data carrier (200), comprising: a card body (210); and at least one device (100) according to one of the preceding claims; wherein the base of the device (100) is integrated into the card body (210) so that the input element (20) and the bezel (22) are accessible from a card surface (211) of the card body (210).
  13. 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. 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.

Description

FINGERPRINT SENSOR WITH IMPROVED BEZEL AND CARD-SHAPED DATA CARRIER WITH SUCH FINGERPRINT SENSOR field of the invention 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. Background of the invention Card-shaped data storage devices are used in a wide range of applications today. For example, such data storage devices can be used for cashless payment of goods or services, for personal identification or for access to Internet-based application programs. Accordingly, there are, for example, card-shaped data carriers in the form of chip cards in general, payment cards such as credit cards or debit cards, as well as ID cards or identity cards, 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 carriers, it is usually necessary to enter a PIN. However, there are also card-shaped data carriers with an integrated biometric authentication element (e.g. a fingerprint sensor) for authorizing processes with the data carrier. Different types of sensors, 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 the height or energy consumption), capacitive fingerprint sensors have now largely become the standard for use in card-shaped data carriers (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 is used to bring the finger placed on it to a certain electrical potential and is connected to a sensor chip via a through-hole (via) and a conductor track on the back inside the card-shaped data carrier. The spatially resolved capacitance change caused by the finger being placed on the sensor 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). Such a bezel originally consisted of a continuous metalized border around the sensor on its front. However, for optical reasons, among other things, the solid metal surface of the bezel in fingerprint sensors for chip cards is increasingly being replaced by a non-continuous, less solid surface, with the electrical connection of the bezel still being made via a through-hole. However, there are various difficulties associated with such a structured bezel design. On the one hand, the reduced material width can lead to tears in the metallization at the inner corners of the bezel over the life of chip cards with fingerprint sensors with a structured bezel, which can cause the segments of the bezel that are not connected to the chip via the vertical interconnect access (VIA) to the sensor chip would be electrically isolated and would no longer be able to contribute to the electrical contact of the finger placed on the sensor. Depending on the position of the finger placed on the fingerprint sensor, the recognition rate would decrease, ie the performance of the fingerprint sensor would be undesirably reduced. On the other hand, 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. In order to be able to operate the fingerprint sensor easily, it is often arranged on the edge of the card body. Since a bezel described above represents a ring-shaped closed conductor path, eddy currents can be induced by high-frequency electromagnetic alternating fields when communicating with the RFID reader through the nearby antenna coil, which increases the attenuation of the antenna coil and thus impairs performance. Description 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. This object is achieved by the subject matter of the independent claim. Exemplary embodiments emerge from the dependent claims and the following description. According to a first aspect, a device is provided comprising a base with a base surface, an input element and a sensor chip. The input element is accommodated in the base and is accessible from the base surface. The input element comprises an input section and a surrounding