FINGERPRINT AUTHORISABLE DEVICE

Abstract

A fingerprint authorizable device includes a control system for controlling the device, where the control system is arranged to provide access to one or more functions of the device in response to identification of an authorized fingerprint, a circuit board for holding electrical components of the device, and a fingerprint sensor assembly including a fingerprint sensor for obtaining fingerprint data for use in the fingerprint authorization, and a two part enclosure for holding the fingerprint sensor, the two part enclosure having an inner casing for attachment to the circuit board and for enclosing the fingerprint sensor and an outer bezel for retaining the fingerprint sensor within the inner casing, where the outer bezel is arranged to be coupled to the inner casing.

Claims

1. A fingerprint authorizable device comprising: a control system for controlling the device, wherein the control system is arranged to provide access to one or more functions of the device in response to identification of an authorized fingerprint; a circuit board for holding electrical components of the device; and a fingerprint sensor assembly including: a fingerprint sensor for obtaining fingerprint data for use in the fingerprint authorization, a protective layer located on top of a sensing surface of the fingerprint sensor, the protective layer comprising a scratch resistant material, and a two part enclosure for holding the fingerprint sensor and the protective layer, the two part enclosure comprising an inner casing for attachment to the circuit board and for enclosing the fingerprint sensor and the protective layer, and an outer bezel for retaining the fingerprint sensor and the protective layer within the inner casing, wherein the outer bezel is arranged to be coupled to the inner casing and holds the protective layer in place on the sensing surface of the fingerprint sensor.

2. A fingerprint authorizable device as claimed in claim 1, wherein the outer bezel is an electrical conductor electrically connected to the device such that it acts to provide an electrical field for the fingerprint sensor.

3. A fingerprint authorizable device as claimed in claim 2, wherein the outer bezel encloses some or all of the outer periphery of the fingerprint sensor and includes a side wall topped by a lip that extends over the top of an outer rim of a sensing surface of the fingerprint sensor.

4. A fingerprint authorizable device as claimed in claim 3, wherein the inner casing has side walls that extend away from the surface of the circuit board and at least partially enclose the fingerprint sensor.

5. A fingerprint authorizable device as claimed in claim 4, comprising an opening in the side wall of the inner casing for allowing electrical connections between the circuit board and the fingerprint sensor.

6. A fingerprint authorizable device as claimed in claim 5, wherein the side wall of the outer bezel extends across the opening in the side wall of the inner casing, thereby ensuring that the fingerprint sensor is enclosed on all sides.

7. A fingerprint authorizable device as claimed in claim 6, wherein an inner surface of the side wall of the outer bezel fits in close proximity to an outer surface of the side wall of the inner casing.

8. A fingerprint authorizable device as claimed in claim 1, wherein the inner casing and the outer bezel have a similar shape and are arranged for complementary fit with one another.

9. A fingerprint authorizable device as claimed in claim 1, wherein the outer bezel is coupled to the inner casing via an interference fit and/or through inter-coupling of resilient elements.

10. A fingerprint authorizable device as claimed in claim 1, wherein the circuit board is a flexible printed circuit board.

11. A fingerprint authorizable device as claimed in claim 1, wherein the inner casing and/or the fingerprint sensor is/are mechanically attached to the circuit board and also electrically attached using the same attachment mechanism for both the mechanical and the electrical attachment.

12. A fingerprint authorizable device as claimed in claim 1, wherein the fingerprint sensor is a pre-existing product and the protective layer is added on top of the sensing surface of the fingerprint sensor.

13. A fingerprint authorizable device as claimed in claim 1, wherein the protective layer has a thickness of 500 μm or less.

14. A fingerprint authorizable device as claimed in claim 1, wherein the protective layer has suitable dielectric properties for operation with a passive or active capacitance fingerprint sensor.

15. A fingerprint authorizable device as claimed in claim 1, wherein the protective layer comprises chemically toughened glass.

16. A fingerprint authorizable device as claimed in claim 1, wherein the outer bezel and the inner casing form a reinforcement member configured to protect the fingerprint sensor assembly against bending moments.

17. A fingerprint authorizable device as claimed in claim 1, wherein the control system is arranged to enroll an authorized user by obtaining fingerprint data via the fingerprint sensor such that the device uses the same fingerprint sensor for enrolment and for authentication.

18. A fingerprint authorizable device as claimed in claim 1, wherein the fingerprint authorizable device is a smartcard such as any of: an access card; a credit card; a debit card; a pre-pay card; a loyalty card; an identity card; and a cryptographic card.

19. A fingerprint authorizable device as claimed in claim 1, wherein the fingerprint authorizable device is control token for controlling access to a system external to the control token, such as a one-time-password device for access to a computer system or a fob for a vehicle keyless entry system.

20. A method of manufacturing a fingerprint authorizable device comprising: a control system for controlling the device, wherein the control system is arranged to provide access to one or more functions of the device in response to identification of an authorized fingerprint; and a fingerprint sensor assembly including a fingerprint sensor for obtaining fingerprint data, a protective layer located on top of a sensing surface of the fingerprint sensor, the protective layer comprising a scratch resistant material, and a two part enclosure for the fingerprint sensor and the protective layer; wherein the method comprises: attaching an inner casing of the two part enclosure to a circuit board of the fingerprint authorizable device, the inner casing being for enclosing the fingerprint sensor and the protective layer; coupling an outer bezel to the inner casing; and thereby retaining the fingerprint sensor and the protective layer within the inner casing using the outer bezel, wherein the bezel holds the protective layer in place on the sensing surface of the fingerprint sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Certain preferred embodiments on the present invention will now be described in greater detail, by way of example only and with reference to the accompanying drawings, in which:

[0068] FIG. 1 illustrates a circuit for a smartcard with a fingerprint sensor;

[0069] FIG. 2 illustrates a first example of the smartcard including an external housing;

[0070] FIG. 3 illustrates a second example of the smartcard which has been laminated;

[0071] FIG. 4 shows a schematic plan view of an inner casing of a fingerprint sensor assembly;

[0072] FIG. 5 shows the inner casing of FIG. 4 in side/cross-section view;

[0073] FIG. 6 shows a side/sectional schematic view of a circuit board fitted with the inner casing and ready to receive a fingerprint sensor and protective layer;

[0074] FIG. 7 shows a plan view of an outer bezel for fitting to the inner casing;

[0075] FIG. 8 shows a side/section view of the outer bezel of FIG. 7;

[0076] FIG. 9 shows the circuit board of FIG. 6 and fitting of the outer bezel to the inner casing;

[0077] FIG. 10 shows the side/sectional view of the circuit board of FIG. 6 with the outer bezel fitted to the inner casing; and

[0078] FIG. 11 shows a schematic plan view of the circuit board of FIG. 10.

DETAILED DESCRIPTION

[0079] By way of example the invention is described in the context of a fingerprint authorized smartcard that includes contactless technology and uses power harvested from the card reader. These features are envisaged to be advantageous features of one application of the proposed fingerprint sensor assembly, but are not seen as essential features. The smartcard may hence alternatively use a physical contact and/or include a battery providing internal power, for example. The fingerprint sensor assembly 130 described herein can also be implemented with appropriate modifications in any other device or system that uses a fingerprint sensor for fingerprint authorization.

[0080] FIG. 1 shows the architecture of a smartcard 102 that is provided with the fingerprint sensor assembly 130. A powered card reader 104 transmits a signal via an antenna 106. The signal is typically 13.56 MHz for MIFARE® and DESFire® systems, manufactured by NXP Semiconductors, but may be 125 kHz for lower frequency PROX® products, manufactured by HID Global Corp. This signal is received by an antenna 108 of the smartcard 102, comprising a tuned coil and capacitor, and then passed to a communication chip 110. The received signal is rectified by a bridge rectifier 112, and the DC output of the rectifier 112 is provided to processor 114 that controls the messaging from the communication chip 110.

[0081] A control signal output from the processor 114 controls a field effect transistor 116 that is connected across the antenna 108. By switching on and off the transistor 116, a signal can be transmitted by the smartcard 102 and decoded by suitable control circuits 118 in the sensor 104. This type of signaling is known as backscatter modulation and is characterized by the fact that the sensor 104 is used to power the return message to itself.

[0082] An accelerometer 16, which is an optional feature, is connected in an appropriate way to the processor 114. The accelerometer 16 can be a Tri-axis Digital Accelerometer as provided by Kionix, Inc. of Ithaca, N.Y., USA and in this example it is the Kionix KXCJB-1041 accelerometer. The accelerometer senses movements of the card and provides an output signal to the processor 114, which is arranged to detect and identify movements that are associated with required operating modes on the card as discussed below. The accelerometer 16 may be used only when power is being harvested from the powered card reader 104, or alternatively the smartcard 102 may be additionally provided with a battery (not shown in the Figures) allowing for the accelerometer 16, and also the related functionalities of the processor 114 and other features of the device to be used at any time.

[0083] The smartcard further includes a fingerprint authentication engine 120 including a fingerprint processor 128 and a fingerprint sensor assembly 130. This allows for enrolment and authorization via fingerprint identification. The fingerprint processor 128 and the processor 114 that controls the communication chip 110 together form a control system for the device. The two processors could in fact be implemented as software modules on the same hardware, although separate hardware could also be used. As with the accelerometer 16 (where present) the fingerprint sensor assembly 130 may be used only when power is being harvested from the powered card reader 104, or alternatively the smartcard 102 may be additionally provided with a battery (not shown) allowing power to be provided at any time for the fingerprint sensor assembly 130 and fingerprint processor 128, as well as the processor 114 and other features of the device.

[0084] The antenna 108 comprises a tuned circuit including an induction coil and a capacitor, which are tuned to receive an RF signal from the card reader 104. When exposed to the excitation field generated by the sensor 104, a voltage is induced across the antenna 108.

[0085] The antenna 108 has first and second end output lines 122, 124, one at each end of the antenna 108. The output lines of the antenna 108 are connected to the fingerprint authentication engine 120 to provide power to the fingerprint authentication engine 120. In this arrangement, a rectifier 126 is provided to rectify the AC voltage received by the antenna 108. The rectified DC voltage is smoothed using a smoothing capacitor and then supplied to the fingerprint authentication engine 120 and other electrical components. Alternatively or additionally a battery may be included as noted above.

[0086] The fingerprint sensor assembly 130, which is described in more detail below with reference to FIGS. 4 to 11, may be mounted on a card housing 134 as shown in FIG. 2 or fitted so as to be exposed from a laminated card body 140 as shown in FIG. 3. The card housing 134 or the laminated body 140 encases all of the components of FIG. 1, and is sized similarly to conventional smartcards. The fingerprint authentication engine 120 may be passive, and hence may be powered only by the voltage output from the antenna 108. Alternatively a battery (not shown) may be provided for powering the fingerprint authorization engine 120. The processor 128 comprises a microprocessor that is chosen to be of very low power and very high speed, so as to be able to perform fingerprint matching in a reasonable time.

[0087] The fingerprint authentication engine 120 is arranged to scan a finger or thumb presented to the fingerprint sensor assembly 130 and to compare the scanned fingerprint of the finger or thumb to pre-stored fingerprint data using the processor 128. A determination is then made as to whether the scanned fingerprint matches the pre-stored fingerprint data. In a preferred embodiment, the time required for capturing a fingerprint image and authenticating the bearer of the card 102 is less than one second.

[0088] If a fingerprint match is determined and/or if appropriate movements are detected via the accelerometer 16, then the processor takes appropriate action depending on its programming. In this example the fingerprint authorization process is used to authorize the use of the smartcard 104 with the contactless card reader 104. Thus, the communication chip 110 is authorized to transmit a signal to the card reader 104 when a fingerprint match is made. The communication chip 110 transmits the signal by backscatter modulation, in the same manner as the conventional communication chip 110. The card may provide an indication of successful authorization using a suitable indicator, such as a first LED 136.

[0089] The fingerprint processor 128 and the processor 114 may receive an indication of a non-fingerprint interaction with the fingerprint sensor assembly 130, which can include any action detectable via the fingerprint sensor assembly 130. The interaction of the user with the card via the fingerprint sensor assembly 130 may be used as a part of a non-fingerprint authorization and also may be used to allow the user to control the smartcard by switching between different operating modes of the smartcard.

[0090] In some circumstances, the owner of the fingerprint smartcard 102 may suffer an injury resulting in damage to the finger that has been enrolled on the card 102. This damage might, for example, be a scar on the part of the finger that is being evaluated. Such damage can mean that the owner will not be authorized by the card 102 since a fingerprint match is not made. In this event the processor 114 may prompt the user for a back-up identification/authorization check via an alternative interaction with the smartcard 102, which in this case includes one or more action(s) detected via the fingerprint sensor assembly 130 and also optionally actions detected via other sensors, such as the accelerometer 16. The card may prompt the user to use a back-up identification/authorization using a suitable indicator, such as a second LED 138. It is preferred for the non-fingerprint authorization to require a sequence of interactions with the card by the user, this sequence being pre-set by the user. The pre-set sequence for non-fingerprint authorization may be set when the user enrolls with the card 102. The user can hence have a non-fingerprint authorization in the form of a “password” entered using non-fingerprint interactions with the card to be used in the event that the fingerprint authorization fails. The same type of non-fingerprint authorization can be used in the event that a user is unable or unwilling to enroll with the card 102 via the fingerprint sensor assembly 130.

[0091] Thus, as well as allowing communication via the circuit 110 with the card reader 104 in response to a fingerprint authorization via the fingerprint sensor assembly 130 and fingerprint processor 128 the processor 114 may also be arranged to allow such communication in response to a non-fingerprint authorization.

[0092] When a non-fingerprint authorization is used the card 102 could be arranged to be used as normal, or it could be provided with a degraded mode in which fewer operating modes or fewer features of the card 102 are enabled. For example, if the smartcard 102 can act as a bank card then the non-fingerprint authorization might allow for transactions with a maximum spending limit lower than the usual maximum limit for the card 102.

[0093] The processor 114 receives the output from the accelerometer 16 and this allows the processor 114 to determine what movements of the smart card 102 have been made. The processor 114 identifies pre-set movements and other actions of the user that are linked with required changes to the operating mode of the smartcard. As discussed above, the movements may include any type of or combination of rotation, translation, acceleration, impulse and other movements detectable by the accelerometer 16. The other actions of the user may include actions detected via the fingerprint sensor, such as taps, swipes and so on as discussed above.

[0094] The operating modes that the processor 114 activates or switches to in response to an identified movement associated with the required change in operating mode may include any mode of operation as discussed above, including turning the card on or off, activating secure aspects of the card 102 such as contactless payment, or changing the basic functionality of the card 102 for example by switching between operating as an access card, a payment card, a transportation smartcard, switching between different accounts of the same type (e.g. two bank accounts), switching between communications protocols (such as blue tooth, wifi, NFC) and/or activating a communication protocol, activating a display such as an LCD or LED display, obtaining an output from the smartcard 102, such as a one-time-password or the like, or prompting the card 102 to automatically perform a standard operation of the smartcard 102.

[0095] The processor 114 has an enrolment mode, which may be activated upon first use of the smartcard 102. In the enrolment mode the user is prompted to enroll their fingerprint data via the fingerprint sensor assembly 130. This can require a repeated scan of the fingerprint via the fingerprint sensor assembly 130 so that the fingerprint processor 128 can build up appropriate fingerprint data, such as a fingerprint template. After a successful or an unsuccessful enrolment of fingerprint data the user is prompted to enter a non-fingerprint authorization. This could be optional in the case of a successful fingerprint enrolment, or compulsory if the fingerprint enrolment was not successful. The non-fingerprint authorization includes a sequence of interactions with the smartcard 102 including at least one action by the user that is detected via the fingerprint sensor assembly 130. The processor 114 can keep a record of these interactions in a memory, and it is arranged to provide at least partial authorization to use the functions of the card in the event that the non-fingerprint authorization is provided by the user.

[0096] The processor 114 can have a learn mode to allow for the user to specify which actions (including combinations of actions/interactions) should activate particular operating modes whilst the smartcard 102 is in use. This type of control of the smartcard 102 might be enabled only after a successful fingerprint or non-fingerprint authorization. In the learn mode the processor 114 prompts the user to make the desired sequence of actions, and to repeat the movements for a predetermined set of times. These movements are then allocated to the required operating mode or to the non-fingerprint authorization. With this latter feature the learn mode can allow for the sequence of movements used for the non-fingerprint authorization to be changed by the user in the same way that a traditional PIN can be changed.

[0097] An example arrangement for the fingerprint sensor assembly 130 will now be described with reference to FIGS. 4 to 11. It should be noted that for the sake of clarity the figures are shown in schematic form only with exaggerated scale. It will be appreciated that the actual sizes of the various parts, in particular their heights, are much less that shown and that the parts would fit together more closely than indicated in the drawings.

[0098] The completed fingerprint sensor assembly 130 is mounted on a circuit board, which in this example is a flexible printed circuit board assembly 24. This is shown schematically in side/section view in FIG. 10 and in plan view in FIG. 11. The fingerprint sensor assembly includes an inner casing 20 which is shown in plan view in FIG. 4 and in cross-section view in FIG. 5. The inner casing is three sided as can be seen in FIG. 4 and also in FIG. 11. Since one side 21 of the inner casing 20 is left open then it is straightforward to connect circuitry from the circuit board 24 to components held within the inner casing 20 since conductive pathways can pass through the open side 21. The upper edges of the inner casing 20 are in this example provided with protruding lugs 22, which extend around the sides of the inner casing 20. These lugs 22 provide a snap-fit with corresponding recesses 32 on an outer bezel 30 as explained further below.

[0099] It should be understood that the lugs 22 and recesses 32 are simply one example of how one might achieve the required interconnections between the inner casing 20 and the outer bezel 30. It would be possible to alternatively have lugs on the outer bezel 30 and recesses on the inner casing 20, or indeed different mechanical arrangements could be used to achieve a suitable snap-fit connection. Couplings known in relation to surface mount technology could be used, or alternatively the connection between the inner casing 20 and the bezel 30 could involve the use of an adhesive or other bonding method.

[0100] FIG. 6 shows the inner casing 20 mounted to a flexible printed circuit board assembly 24 and ready to receive a fingerprint sensor 26 and also a protective layer 28. These are inserted through the open top of the inner casing 20 and then connected to circuitry on the flexible circuit board in an appropriate fashion for example by the use of surface mount technology, soldering, or conductive adhesive. The three walls of the inner case 20 are slightly taller than the height of the fingerprint sensor 26 together with the protective layer 28, and this height difference is exaggerated in the Figures. The fingerprint sensor 26 can be an area fingerprint sensor 26 of any suitable type. The protective layer 28 can be any suitably thin scratch resistant material that is compatible with the fingerprint sensor 26 such as, for example chemically toughened glass. One possible material is alkali-aluminosilicate sheet glass, such as the glass sold under the trade name Gorilla Glass® and manufactured by Corning Inc. of New York, USA. This type of glass is commonly used as a cover glass for touch screens on mobile devices such as smartphones and other similar cover glass products could be used for the protective layer 28. The protective layer 28 is about 400 μm thick, which means that it can be added on top of suitable a fingerprint sensor 26 without adversely affecting the total width of the fingerprint sensor assembly 130, and in particular whilst allowing the smartcard 102 with the fingerprint sensor assembly 130 to meet the thickness restrictions of ISO 7816.

[0101] As noted above an outer bezel 30 is mounted to the inner case 20. The outer bezel 30 is shown in plan view in FIG. 7 and in side/sectional view in FIG. 8. It has four side walls forming an open frame with the sides of the frame having an inverted, L-shape section in order that the bezel 30 surrounds the sides of the fingerprint sensor 26 and the protective layer 28. It also extends across and frames the top of the fingerprint sensor 26 and the protective layer 28. This means that the bezel 30 can act to hold the fingerprint sensor 26 and the protective layer 28 in place, including holding the protective layer 28 firmly against the fingerprint sensor 26. Moreover, in most cases the bezel 30 is made from a conductive material and hence provides the required conductive field for proper functionality of the fingerprint sensor 26 in terms of capturing the fingerprint. The presence of a conductive outer element is a requirement for many types of fingerprint sensor. In the case that the bezel 30 is used as a conductive element then the inner casing 20 can also be made of a conductive material allowing for an electrical connection via the inner casing 20 to the circuit on the circuit board 24. The inner casing 20 can be connected to the circuit board 24 by soldering or via conductive adhesive, for example, in order to both bond the inner casing 20 to the circuit board 24 as well as electrically connecting the inner casing 20 to the circuit which is formed on the circuit board 24.

[0102] The bezel 30 is fitted to the inner casing 20 as shown in FIGS. 9 and 10, in this example this is done with a snap-fit utilizing the lugs 22 and corresponding recesses 32. The use of a snap-fit connection, or similar mechanical connection, means that the bezel 30 can be simply pushed into place, whilst the fingerprint sensor 26 and protective layer 28 are already held within the inner casing 20, such that it is simple to both secure the fingerprint sensor 26 and protective layer 28 to the inner casing 20, and to complete the fingerprint sensor assembly 130 by providing a suitable electrically conductive bezel 30, if required, about the fingerprint sensor 26. Moreover, by the use of a two-part bezel assembly made up of the inner casing 20 and the outer bezel 30 then the fingerprint sensor assembly 130 is provided with reinforcement and is well protected from torsional forces that might otherwise be passed to the fingerprint sensor 26 and/or the protective layer 28, which can be relatively fragile in terms of bending and torsion forces. This is particularly helpful in the case of the examples where the fingerprint sensor assembly is used on a smart card 102, especially with a laminated card as shown in FIG. 3. However, the advantages arising from the use of the fingerprint sensor assembly 130 and assembly method described above are also beneficial in other contexts where a fingerprint sensor is used for a biometrically authorized device, for example a control token such as a vehicle keyless entry fob.

[0103] Suitable methods for manufacturing various aspects of an electronic card of the type described herein are set forth, for example, in WO2013/160011, U.S. 62/262,944, U.S. 62/262,943, U.S. 62/312,773, U.S. 62/312,775 and U.S. 62/312,803.