Patent Publication Number: US-2022230037-A1

Title: Enrolment device for a biometric smart card

Description:
This application relates to an electronic device for transferring enrolment data to a biometric smart card. 
     The biometric smart card contains an integrated circuit device. The biometric smart card resembles a credit card in size and shape. The biometric smart card is widely used in many application areas. Standardized biometric smart cards, such as those with surface contacts that conform to ISO/IEC 7816 may be used with smart card reading/writing devices for performing payment transaction, as an example. 
     For improved security, a reference biometric template of an owner, such as a right or left thumb fingerprint, is stored in a secure memory of a biometric smart card of the owner. In an enrolment phase, an electronic device is used to sense and obtain fingerprint information of a finger of the card owner and to transfer the fingerprint information to the biometric smart card for storing as a reference biometric template. To make a payment with the biometric smart card, an electronic terminal or device captures fingerprint information of the card user and later compares it with the reference biometric template of the biometric smart card. A successful payment transaction can be done only when the captured fingerprint information essentially matches with the reference biometric template of the biometric smart card. 
     The biometric smart card can also be used to control access to access-controlled areas, such as rooms or premises of hotels, corporate and government buildings. It can also be used to determine whether a person is eligible for a ticket concession, or for obtaining a service based on the biometric identity of the person. 
     GB2556625 discloses a method of enrolling of a user onto a biometric device, such as a smartcard. The method comprises a step of reading a fingerprint of the user using a fingerprint sensor of an enrolment processing unit, followed by a step of extracting biometric data corresponding to the fingerprint, wherein the extraction is performed in a secure processing environment of the enrolment processing unit. The method further includes a step of converting the biometric data to secure biometric data within the secure processing environment, and a step of transmitting the secure biometric data from the enrolment processing unit to the smartcard. The processing unit is also configured to supply power to the smartcard. 
     It is an object of this application to provide an enrolment device for providing a biometric smart card with a biometric template. 
     The application provides a biometric enrolment setup or arrangement. The biometric enrolment setup includes a biometric card and an enrolment card. 
     The biometric card refers to a smart card, which is configured to store a reference fingerprint biometric template. The reference fingerprint biometric template often contains a digital representation of the biometric information of a user&#39;s finger, wherein the digital representation is often secured such that it cannot be easily duplicated. The reference biometric template is used to authenticate or determine an identity of a person in order to allow the person to access systems, devices, or data. 
     The enrolment card is used for enabling the biometric card to generate a reference biometric template from a fingerprint of a user and to store the generated reference biometric template. 
     In detail, the biometric card includes a plurality of contact pads, a fingerprint sensor, a first microcontroller unit, and a first card body. The first microcontroller unit is also called card microcontroller unit. 
     The contact pads can conform to ISO standard 7816 and they can have six or eight electrically conductive pads. 
     The first microcontroller unit is electrically connected to the contact pads and to the fingerprint sensor. 
     The first card body often comprises a thin flat piece of plastic. Both the fingerprint sensor and the first microcontroller unit are embedded in the first card body while the contact pads are provided at predetermined positions on a surface of the first card body. 
     Referring to the enrolment card, it includes a battery, a second microcontroller unit, a plurality of contact pins, and a second card body with a card engagement element. The second microcontroller unit is also called enrolment microcontroller unit. 
     The battery is often portable, and the second microcontroller unit is electrically connected to the battery. The contact pins are electrically connected to the battery and to the second microcontroller unit. The contact pins are positioned for contacting the corresponding contact pads of the biometric card. 
     The second card body also often comprises a thin flat piece of plastic, which is sized to correspond to the first card body of the biometric card. The second card body and the first card body often have essentially the same dimensions. Both the battery and the second microcontroller unit are embedded in the second card body such that the second card body encloses the battery and the second microcontroller unit. In other words, an external surface of the second card body surrounds the battery the second microcontroller unit. 
     The biometric enrolment setup provides an enrolment mode for generating a reference biometric template and for storing it in a memory of the first microcontroller unit of the biometric card. 
     In the enrolment mode, the battery is intended for storing electrical power. 
     A user then places the biometric card next to the enrolment card such that the card engagement element of the second card body of the enrolment card engages with the first card body of the biometric card. This engagement also allows a user to align the second card body with the first card body for allowing the contact pins of the enrolment card to contact the corresponding contact pads of the biometric card. 
     The battery of the enrolment card then provides electrical power to the contact pins, to the contact pads, and to the first microcontroller unit of the biometric card for energising the first microcontroller unit. 
     The second microcontroller unit later sends an enrolment command to the first microcontroller unit to commence an enrolment process. 
     The user afterward places a finger of the user on the fingerprint sensor, wherein the fingerprint sensor senses and obtains fingerprint biometric information of the finger for transferring to the first microcontroller unit. 
     The first microcontroller unit later generates a reference fingerprint biometric template according to the obtained fingerprint biometric information and then stores the generated reference fingerprint biometric template in the memory of the first microcontroller unit. 
     The biometric enrolment setup also provides an operation mode. 
     In the operation mode, the contact pads are intended for contacting with a part of an electronic device, such as a credit card reader. 
     A user later places a finger of the user on the fingerprint sensor. The fingerprint sensor then obtains fingerprint biometric information of the finger. 
     The first microcontroller unit afterward compares this obtained fingerprint biometric information with the above-mentioned reference fingerprint biometric template to authenticate an identity of the user for determining whether the user is allowed or is eligible, for example, to use a credit card for payment. 
     The card engagement element of the enrolment card allows quick and easy alignment between the enrolment card and the biometric card, thereby enabling the user to perform self-enrolment of the biometric card easily and efficiently 
     Such biometric card and the enrolment card can be produced at low cost because both can be produced using the same equipment and same plastic material and with essentially the same dimensions. This also allows easy delivery of these cards to a user, using common methods such as mailing. 
     The second card body of the enrolment card can include an inlay. The inlay comprises a stack of plastic sheets and several components. The components refer to the second microcontroller unit, the battery, and a plurality of electrical connecting means. The electrical connecting means include electrical wires. One or more holes can be provided within the stack of the plastic sheets for receiving the battery and/or the second microcontroller unit. The battery is electrically connected to the second microcontroller unit via the electrical connecting means. 
     The card engagement element can include a fingerprint opening. 
     In use, the fingerprint opening of the enrolment card is aligned with the fingerprint sensor of the biometric card such that the fingerprint opening can receive a finger of a user to contact with the fingerprint sensor. 
     Furthermore, the fingerprint opening also serves orienting the enrolment card with the respect to the biometric card such that the biometric card is aligned with the enrolment card and such that the contact pins of the enrolment card are aligned to contact the corresponding contact pads of the biometric card. In short, this enables the contact pins to contact the contact pads. 
     The card engagement element can further include a card fixing friction opening for fixing the contact pins to the corresponding contact pads. In use, the card fixing friction opening of the enrolment card receives a finger of a user. The finger presses the card fixing friction opening onto the biometric card. The pressing fixes the finger to the biometric card, and it fixes the enrolment card onto the biometric card, thereby preventing the biometric card from moving or shifting with respect to the enrolment card. This fixing also prevents the contact pins of the enrolment card from moving away from the corresponding contact pads of the biometric card. In effect, this enables the contact pins to maintain a firm contact with the contact pads. 
     In one implementation, the second card body of the enrolment card is provided with a rectangular shape. The first card body of the biometric card is also sized to have essentially the same rectangular shape. 
     The card engagement element can include one or more card reception openings that are provided on an edge portion of the second rectangular card body. The card reception openings are configured to engage with an edge part of the first rectangular card body such that the first rectangular card body is positioned with respect to the second rectangular card body to allow the contact pins to contact the corresponding contact pads. 
     The edge portion can be provided near a short edge of the second rectangular card body. The contact pins contact the corresponding contact pads when the card reception openings engage with the first rectangular card body of the biometric card and edges of the second rectangular card body are aligned with corresponding edges of the first rectangular card body along straight lines. 
     Alternatively, the edge portion can be provided near a long edge of the second rectangular card body, wherein the long edge is essentially perpendicular to the short edge. The card engagement element can further include one or more alignment lines for positioning the first rectangular card body with respect to the second rectangular card body such that the contact pins contact the corresponding contact pads. 
     The enrolment card can further include a low power means for configuring the second microcontroller unit into a low power mode, wherein the second microcontroller unit temporarily stops operating. This is for saving energy and for extending an operating life of the battery. The low power means can later be disabled for activating the second microcontroller unit. 
     In one implementation, the low power means comprises a wire that electrically connects a low power terminal of the second microcontroller unit to an electrical ground. The wire is later cut for activating the second microcontroller unit. The cut wire does not electrically connect the low power terminal to the electrical ground. 
     The application also provides an enrolment card for a biometric card with a first card body. 
     The enrolment card includes a battery for providing electrical power and an enrolment microcontroller unit that is electrically connected to the battery. The enrolment card further includes a plurality of contact pins, which are electrically connected to the battery and to the enrolment microcontroller unit. The enrolment card also includes a second card body with a card engagement element. The second card body, which is often a thin flat piece of plastic, is sized to correspond to the first card body. Both the battery and the enrolment microcontroller unit are embedded in the second card body such that the second card body encloses both the battery and the enrolment microcontroller unit. 
     The enrolment card provides an enrolment mode. In the enrolment mode, the card engagement element engages with the first card body of the biometric card for allowing the contact pins to contact corresponding contact pads of the biometric card. 
     The battery then provides the electrical power to the enrolment microcontroller unit, and to a card microcontroller unit of the biometric card. 
     The second card body of the enrolment card can include an inlay. The inlay comprises a stack of plastic sheets. At least one hole can be provided within the stack of plastic sheets for receiving the battery and/or the enrolment microcontroller unit. 
     The card engagement element can include a fingerprint opening for allowing a finger of a user to contact the fingerprint sensor and for allowing the user to align the biometric card with the enrolment card such that the contact pads contact the corresponding contact pins. 
     The card engagement element can further include a card fixing friction opening for preventing the contact pins from moving with respect to the corresponding contact pads. 
     In one implementation, the second card body is provided with a rectangular shape. The first card body is also sized to have essentially the same rectangular shape. 
     The card engagement element can include one or more card reception openings that are provided on an edge portion of the second rectangular card body. 
     The edge portion can be provided near a short edge of the second rectangular card body. 
     Alternatively, the edge portion can be provided near a long edge of the second rectangular card body, wherein the long edge is essentially perpendicular to the short edge. The card engagement element can further include one or more alignment lines for positioning the first rectangular card body with respect to the second rectangular card body such that the contact pins contact the corresponding contact pads. 
     The enrolment card can further include a low power means for configuring the enrolment microcontroller unit into a low power mode. In one implementation, the low power means comprises a wire that connects a low power terminal of the enrolment microcontroller unit to an electrical ground. 
     The application also provides a biometric card. The biometric card includes a plurality of contact pads that conform to ISO standard 7816, a fingerprint sensor, and a card microcontroller unit that is electrically connected to the contact pads and to the fingerprint sensor. The biometric card further includes a card body which is often a thin flat piece of plastic in a rectangular shape. Both the fingerprint sensor and the card microcontroller unit are embedded in the card body. The contact pads are configured to receive electrical power from a battery of an enrolment card while the fingerprint sensor is configured to obtain fingerprint biometric information of a user for transferring to the card microcontroller unit. The card microcontroller unit is configured to generate a fingerprint reference biometric template according to the obtained fingerprint biometric information and to store the fingerprint reference biometric template in a memory of the card microcontroller unit. 
     The application further provides a method for enrolment of a biometric card using an enrolment card. The method includes a step of engaging a card engagement element of the enrolment card with the biometric card for allowing contact pins of the enrolment card to contact corresponding contact pads of the biometric card. The method further includes a step of providing electrical power by a battery of the enrolment card to a card microcontroller unit of the biometric card, followed by a step of obtaining fingerprint biometric information of a user by a fingerprint sensor of the biometric card. The card microcontroller unit of the biometric card later generates a reference fingerprint biometric template according to the obtained fingerprint biometric information. The card microcontroller unit afterward stores the generated reference fingerprint biometric template in a memory of the card microcontroller unit of the biometric card. 
     The application also provides another biometric enrolment setup. The biometric enrolment setup includes a biometric card and an enrolment card for transferring fingerprint biometric information of a user to the biometric card. The biometric card comprises a first antenna, a fingerprint sensor, and a first microcontroller unit. The first microcontroller unit is electrically connected to the first antenna and to the fingerprint sensor. The biometric card further includes a first card body. The fingerprint sensor, the first microcontroller unit, and the first antenna are embedded in the first card body. The enrolment card comprises a battery for providing electrical power and a second microcontroller unit that is electrically connected to the battery. The enrolment card further comprises a second antenna that is electrically connected to the second microcontroller unit, and a second card body. The battery, the second microcontroller unit, and the second antenna are embedded in the second card body such that the second card body encloses the battery, the second microcontroller unit, and the second antenna. 
     The biometric enrolment setup provides an enrolment mode. In the enrolment mode, the biometric card is positioned near the enrolment card. The second microcontroller unit later receives electrical power from the battery. The second microcontroller unit then powers the second antenna for communicatively connecting the second antenna with the first antenna. The second antenna afterward transmits the electrical power to the first antenna, and to the first microcontroller unit. The fingerprint sensor afterward obtains fingerprint biometric information of a user for transferring to the first microcontroller unit. The first microcontroller unit then generates a reference fingerprint biometric template according to the obtained fingerprint biometric information and stores the reference fingerprint biometric template in a memory of the first microcontroller unit. 
     The second card body of the enrolment card can include an inlay. The inlay comprises a stack of plastic sheets. At least one hole can be provided within the stack of plastic sheets for receiving the battery and/or the second microcontroller unit. 
     The enrolment card can include a low power means for configuring the second microcontroller unit into a low power mode. In one implementation, the low power means comprises a wire that connects a low power terminal of the second microcontroller unit to an electrical ground. 
     The application further provides another enrolment card for a biometric card that is provided with a first antenna. The enrolment card includes a battery for providing electrical power and an enrolment microcontroller unit that is electrically connected to the battery. The enrolment card further includes a second antenna that is electrically connected to the enrolment microcontroller unit, and a card body. The battery, the enrolment microcontroller unit, and the second antenna are embedded in the card body such that the card body encloses the battery, the enrolment microcontroller unit, and the second antenna. The enrolment card provides an enrolment mode. In the enrolment mode, the enrolment card is positioned near the biometric card. The enrolment microcontroller unit later receives the electrical power from the battery. The second microcontroller unit then powers the second antenna to communicatively connect with the first antenna. The second antenna afterward transmits the electrical power to the first antenna and to a card microcontroller unit of the biometric card. 
     The card body of the enrolment card can include an inlay. The inlay comprises a stack of plastic sheets. At least one hole can be provided within the stack of plastic sheets for receiving the battery and/or the enrolment microcontroller unit. 
     The enrolment card can include a low power means for configuring the enrolment microcontroller unit into a low power mode. In one implementation, the low power means comprises a wire that connects a low power terminal of the enrolment microcontroller unit to an electrical ground. 
     The application also provides another biometric card. The biometric card includes an antenna, a fingerprint sensor, and a card microcontroller unit. The card microcontroller unit is electrically connected to the antenna and to the fingerprint sensor. The biometric card further includes a card body, wherein the fingerprint sensor, the card microcontroller unit, and the antenna are embedded in the card body such that the card body encloses the fingerprint sensor, the card microcontroller unit, and the antenna. The antenna is configured to receive electrical power from a battery of an enrolment card while the fingerprint sensor is configured to obtain fingerprint biometric information of a user. The card microcontroller unit is configured to generate a reference fingerprint biometric template according to the obtained fingerprint biometric information and to store the reference fingerprint biometric template in a memory of the card microcontroller unit. 
    
    
     
         FIG. 1  illustrates a front surface of a biometric smart card, 
         FIG. 2  illustrates a rear surface of an enrolment card for the biometric smart card of  FIG. 1 , 
         FIG. 3  illustrates a front surface the enrolment card of  FIG. 2 , 
         FIG. 4  illustrates an engagement of the biometric smart card of  FIG. 1  with the enrolment card of  FIG. 2 , wherein the rear surface of the enrolment card is placed on top or next to the front surface of the biometric smart card of  FIG. 1 , 
         FIG. 5  illustrates an engagement of the biometric smart card of  FIG. 1  with another enrolment card, which is a variant of the enrolment card of  FIG. 2 , 
         FIG. 6  illustrates a cross-sectional view of the enrolment card of  FIG. 5  being engaged with the biometric smart card of  FIG. 1 , taken along line AA of  FIG. 5 , 
         FIG. 7  illustrates a rear surface of another enrolment card, which is a variant of the enrolment card of  FIG. 2 , 
         FIG. 8  illustrates a front surface of the enrolment card of  FIG. 7 , 
         FIG. 9  illustrates an engagement of the biometric smart card of  FIG. 1  with the enrolment card of  FIG. 7 , wherein a part of the biometric smart card of  FIG. 1  is inserted into cut-out portions of the enrolment card of  FIG. 7 , 
         FIG. 10  illustrates a rear surface of a further enrolment card, which is a variant of the enrolment card of  FIG. 2 , 
         FIG. 11  illustrates a front surface of the enrolment card of  FIG. 10 , and 
         FIG. 12  illustrates an engagement of the biometric smart card of  FIG. 1  with the enrolment card of  FIG. 10 , wherein a part of the biometric smart card of  FIG. 1  is inserted into cut-out portions of the enrolment card of  FIG. 10 . 
     
    
    
     In the following description, details are provided to describe embodiments of the application. It shall be apparent to one skilled in the art, however, that the embodiments may be practiced without such details. 
     Some parts of the embodiments have similar parts. The similar parts may have the same names or the similar part numbers with an alphabet symbol. The description of one similar part also applies by reference to another similar part, where appropriate, thereby reducing repetition of text without limiting the disclosure. 
       FIG. 1  shows a biometric smart card  1  for receiving a reference biometric data from an enrolment card  10  of  FIGS. 2 and 3 . 
     The biometric smart card  1  includes a rectangular card body  2 , a contact pad module  4 , a fingerprint sensor  5 , and a card microcontroller unit  8 . The contact pad module  4 , the fingerprint sensor  5 , and the card microcontroller unit  8  are embedded within the card body  2 . An external face of the contact pad module  4  and an external surface of the fingerprint sensor  5  are aligned with a front surface of the card body  2 . The card microcontroller unit  8  is electrically connected to the contact pad module  4  and to the fingerprint sensor  5 . 
     The card body  2  has a shape of a rectangular credit card. The credit card has two short edges that are parallel to each other and two long edges that are parallel to each other. 
     The contact pad module  4  includes a plurality of contact pads  3 , which are provided on the external face of the contact pad module  4  near a short edge  6  of the card body  2 . The contact pads  3  include an electrical ground (GND) contact pad  3   a , a power supply (VCC) contact pad  3   b , and multiple general-purpose input/output (GPIO) contact pads  3   c . The contact pads  3   a ,  3   b  and  3   c  are respectively sized and positioned on predetermined positions of the front surface of the card body  2  according to the ISO standard 7816. The number of contact pads  3  can be six or can be eight. 
     The fingerprint sensor  5  includes a plurality of sensing elements that are provided on the external surface of the fingerprint sensor  5 . The sensing elements are configured to contact a finger, to sense, and to obtain a fingerprint data of the finger. The fingerprint sensor  5  is located near another short edge that is opposite the short edge  6 . 
     The card microcontroller unit  8  includes a microprocessor with a memory module. The microprocessor includes an electrical ground terminal that is electrically connected to the first GND contact pad  3   a  and a power supply voltage terminal that is electrically connected to the VCC contact pad  3   b  for receiving an electrical supply voltage from the VCC contact pad  3   b . The card microcontroller unit  8  also includes few signal terminals, which are electrically connected to the first GPIO contact pads  3   c  for receiving signals from and for transmitting signals to a card reader. The memory module is configured to store a fingerprint matching algorithm. The microprocessor is configured to execute instructions of the fingerprint matching algorithm. 
     As seen in  FIGS. 2 and 3 , the enrolment card  10  includes a rectangular card body  12 , a contact pin module  28 , an enrolment microcontroller unit  15 , a battery  24 , a display unit  21 , a near field communication (NFC) tag  27 , and a quick response (QR) code  30 . The contact pin module  28 , the enrolment microcontroller unit  15 , the battery  24 , the display unit  21 , and the NFC tag  27  are embedded within the card body  12 . An external face of the contact pin module  28  is aligned with a rear surface of the card body  12  while an external face of the display unit  21  and the QR code  30  are aligned with a front surface of the card body  12 . The battery  24  is electrically connected to the enrolment microcontroller unit  15  and to the display  21 . The enrolment microcontroller unit  15  is also electrically connected to the display  21 , to the contact pin module  28 , and to the NFC tag  27 . 
     The card body  12  has an essentially rectangular shape and a size that are similar to the card body  2  of the biometric smart card  1 . The card body  12  includes a short edge  16 , a fingerprint opening  13 , and a card fixing friction cut-out  14 . The cut-out  14  is located at or next to the short edge  16  while the fingerprint opening  13  is located near another short edge that is opposite the short edge  16 . 
     The fingerprint opening  13  has a shape and a size that corresponds to a shape and a size of the fingerprint sensor  5  of the biometric smart card  1 . As better seen in  FIG. 4 , the fingerprint opening  13  is positioned at a predetermined location of the card body  12 , which corresponds to the location of the fingerprint sensor  5  of the biometric smart card  1 . 
     The card fixing friction cut-out  14  is sized according to a size of a fingerprint of a finger. 
     The contact pin module  28  includes a plurality of contact pins  18 , which may be provided in the form of solder balls or any other way. The solder balls refer to balls of solder that can protrude from the rear surface of the card body  12  for contacting with the contact pad  3 . The contact pins  8  include a GND contact pin  18   a , a VCC contact pin  18   b , and multiple GPIO contact pins  18   c . The contact pins  18   a ,  18   b , and  18   c  are respectively sized and positioned on predetermined positions of the rear surface of the card body  12  near the card fixing friction cut-out  14  of the card body  12 . In particular, the GND contact pin  18   a  is configured to contact the GND contact pad  3   a , the VCC contact pin  18   b  is configured to contact the VCC contact pad  3   b , and the GPIO contact pins  18   c  is configured to contact the corresponding GPIO contact pads  3 . 
     The battery  24  refers to a flat lithium-ion battery that can be laminated into the card body  12 . The battery  24  includes an anode and a cathode. In a general sense, the battery  24  can refer to other types of battery. 
     The enrolment microcontroller unit  15  includes a microprocessor with a memory module. The microprocessor includes an electrical ground terminal that is electrically connected to the GND contact pin  18   a  and to the anode of the battery  24 , and a power supply voltage terminal that is electrically connected to the VCC contact pin  18   b  and to the cathode of the battery  24 . The microprocessor also includes few signal terminals, which are electrically connected to the GPIO contact pins  18   c . The microprocessor further includes a low-power or power-down terminal, which is connected to a first end of a conductive wire  20  that is embedded within the card body  12 . A second end of the wire  20  is connected to the electrical ground terminal of the microprocessor for configuring the microprocessor to a low-power mode or standby mode, wherein the microprocessor temporarily stops operating for energy saving. The wire  20  is placed such that a part of the wire  20  is located near a designated corner portion of the card body  12 , wherein the designated corner portion is marked with a symbol or picture, such as a dotted line  29 . 
     The display unit  21  includes a display screen. An external surface of the display screen is aligned with the front surface of the card body  12 . 
     The NFC tag  27  includes an NFC microchip with an antenna, which is communicatively connected to the NFC microchip. The microchip includes a memory unit. 
     The QR code  30  refers to a two-dimensional barcode, which is either printed or provided with a label on the front surface of the card body  12 . 
     The card body  12  of the enrolment card  10  is provided with an inlay. The inlay comprises a stack of plastic sheets and several components. The components include the enrolment microcontroller unit  15 , the battery  24 , at least one module lead frame and a plurality of electrical wires. The module lead frame refers to a metal structure for carrying electrical signal from one part of the lead frame to another part of the lead frame. Several holes are provided within the stack of the plastic sheets for receiving the enrolment microcontroller unit  15 , the battery  24 , and other components. The enrolment microcontroller unit  15  are connected to the battery  24  via the module lead frames and/or the electrical wires. 
     In use, a card owner or a user receives a biometric smart card  1  and a corresponding enrolment card  10  from, for example, a financial institution, such as a bank. The wire  20  is connected to the electrical ground terminal and to the low-power terminal of the enrolment microcontroller unit  15 . The enrolment microcontroller unit  15  is placed in the low-power mode. 
     The user then cuts away the designated corner portion of the enrolment card  10 . The cutting removes a part of the wire  20 . 
     This causes the low-power terminal of the enrolment microcontroller unit  15  to be disconnected from the electrical ground terminal. The enrolment microcontroller unit  15  is afterward changed from the low-power mode to a normal power mode. 
     The user later moves the biometric smart card  1  to engage with the enrolment card  10 , wherein the rear surface of the enrolment card  10  is placed on top of the front surface of the biometric smart card  1  in a stack such that all edges of the enrolment card  10  are substantially aligned with all corresponding edges of the biometric smart card  1 . The short edge  6  of the biometric smart card  1  is placed adjacent to the corresponding short edge  16  of the enrolment card  10 . The fingerprint opening  13  of the enrolment card  10  is placed next to the fingerprint sensor  5  of the biometric smart card  1  and the contact pins  18   a ,  18   c , and  18   c  face and touch the corresponding contact pads  3   a ,  3   b , and  3   c.    
     The user then places a finger onto the card fixing friction cut-out  14  of the enrolment card  10  and also presses the enrolment card  10  against the biometric smart card  1 . The pressing of the finger onto the card fixing friction cut-out  14  generates frictional force, which acts to prevent the enrolment card  10  from moving with respect to the biometric smart card  1 . 
     The pressing also causes the contact pins  18  to contact the corresponding contact pads  3  firmly. In particular, the GND contact pin  18   a  contacts the GND contact pad  3   a  while the VCC contact pin  18   b  contacts the VCC contact pad  3   b  to provide an electrically conductive path for allowing electrical power transmission from the battery  24  of the enrolment card  10  to the electronic components of the biometric smart card  1 . The GPIO contact pins  18   c  also contact the GPIO contact pads  3   c  to provide an electrical signal path between the enrolment microcontroller unit  15  of the enrolment card  10  and the card microcontroller unit  8  of the biometric smart card  1 . 
     The battery  24  then provides an electric supply voltage to the VCC contact pin  18   b . The voltage is later transmitted to the VCC contact pad  3   b  of the biometric smart card  1  and to the card microcontroller unit  8  for powering the card microcontroller unit  8 . The powered card microcontroller unit  8  later sends a ready signal to the GPIO contact pads  3   c , to the GPIO contact pins  18   c , and to the enrolment microcontroller unit  15 . The enrolment microcontroller unit  15  afterward transmits an enrolment signal to the GPIO contact pins  18   c , to the GPIO contact pads  3   c , and to the card microcontroller unit  8  to commence the enrolment of the biometric smart card  1 . The enrolment microcontroller unit  15  then directs the display unit  21  to display a text message for indicating to the user that the biometric smart card  1  is ready for enrolment. 
     The user then places the finger onto the fingerprint opening  13  and onto the fingerprint sensor  5  of the biometric smart card  1 . The fingerprint sensor  5  afterward senses the finger and captures fingerprint data of the finger. The fingerprint sensor  5  later transmits the captured fingerprint data to the card microcontroller unit  8 . 
     The card microcontroller unit  8  then generates a fingerprint biometric template according to the captured fingerprint data. The card microcontroller unit  8  afterwards stores the fingerprint biometric template. 
     The card microcontroller unit  8  then sends an enrolment completion signal to the enrolment microcontroller unit  15  of the enrolment card  10 . The enrolment microcontroller unit  15  afterward receives the enrolment completion signal and then directs the display unit  21  to display a text message to indicate that the enrolment is completed. The user later removes the finger from the fingerprint opening  13 . 
     The function of the NFC tag  27  can be used to link the biometric smart card  1  logically to a corresponding application of a mobile device, such as a mobile phone. Alternatively, the QR code  30  can serve the same functionality. 
       FIGS. 5 and 6  show another enrolment card  10 A, which is a variant of the enrolment card  10 . The enrolment card  10 A is engaged with the biometric smart card  1 . 
     The enrolment card  10 A and the enrolment card  10  have similar parts, which are arranged similarly. 
     Differences between the enrolment card  10 A and the enrolment card  10  only relates to the card body. The differences are described as below. 
     The enrolment card  10 A has a rectangular card body  12 A, which has a size that is similar to the size of the biometric smart card  1 . 
     The card body  12 A is similar to the card body  12  of the enrolment card  10 . But the card body  12 A does not have the card fixing friction cut-out  14  of the card body  12 . The card body  12 A further includes a shallow recess  32  and a contact pin pressing area  33 . The recess  32  is located at a rear surface of the card body  12 A while the contact pin pressing area  33  is located on a front surface of the card body  12 A, which is opposite the recess  32 . The recess  32  is provided with contact pins  18 , which protrude from a major surface of the recess  32 . The contact pin pressing area  33  can be marked with, for example, a rectangle. 
     In use, a user engages the enrolment card  10  with the biometric smart card  1  such that the contact pins  18  are placed next to the corresponding contact pads  3  with a gap between the contact pins  18  and the corresponding contact pads  3 . The user later places a finger onto the contact pin pressing area  33  and presses the finger onto the enrolment card  10  towards the biometric smart card  1 . The pressing causes the major surface of the recess  32  to move towards the front surface of the biometric smart card  1 . The movement acts to reduce the gap until the contact pins  18  contact the corresponding contact pads  3  firmly. 
     The recess  32  allows the contact pins  18  not to touch the contact pads  3  even when the rear surface of the enrolment card  10  touches the front surface of the biometric smart card  1 . 
     This can avoid friction between the contact pads  3  and the contact pins  18  when the biometric smart card  1  slides with respect to the enrolment card  10 , thereby maintaining the contact integrity of the contact pads  3  and the contact pins  18 . 
       FIGS. 7 and 8  show another enrolment card  10 B, which is a variant of the enrolment card  10 . 
     The enrolment card  10 B and the enrolment card  10  have similar parts, which are arranged similarly. 
     Differences between the enrolment card  10 B and the enrolment card  10  only relates to the card body. The differences are described as below. 
     The enrolment card  10 B has a rectangular card body  12 B, which has a size that is similar to the size of the biometric smart card  1 . 
     The card body  12 B includes a short edge  16  and a rectangular short edge portion  17 , which is adjacent or next to the short edge  16 . 
     The short edge portion  17  includes a first edge part  45 , a first card reception opening  19 , a second edge part  46 , a second card reception opening  23 , and a third edge part  47 . The first edge part  45  is positioned next to the first card reception opening  19 , which is positioned next to the second edge part  46 . The second edge part  46  is positioned next to the second card reception opening  23 , which is positioned next to the third edge part  47 . An edge of the first edge part  45 , an edge of the second edge part  46 , and an edge of the third edge part  47  are aligned with the short edge  16 . 
     The second edge part  46  is provided with multiple contact pins  18 , which are located on a rear surface of the second edge part  46 . 
     In one implementation, the card reception openings  19  and  23 , are similar. Each card reception opening  19  and  23  includes three segments, namely, a base  35 , a first curved side edge  39 , and a second curved side edge  43 . The base  35  is essentially parallel to the short edge  16 . The base  35  has a first end and a second end, which is opposite the first end. The first curved side edge  39  has a first end that is connected to the first end of the base  35  and a second end that is connected to a part of the short edge  16 . The second curved side edge  43  has a first end that is connected to the second end of the base  35  and a second end that is connected to another part of the short edge  16 . The second curved side edge  43  is separated from the first curved side edge  39  by a gap. 
     As seen in  FIG. 9 , the card reception openings  19  and  23  are sized such that they act as guides for facilitating the engagement of the biometric smart card  1  with the enrolment card  10 B so that the contact pads  3  can contact the corresponding contact pins  18  easily. 
     In detail, a user inserts a short edge portion near the short edge  6  of the biometric smart card  1  into the card reception openings  19  and  23  of the enrolment card  10 B such that the short edge  6  of the biometric smart card  1  touches the bases  35  of the card reception openings  19  and  23  and such that long edges of the biometric smart card  1  and long edges of the enrolment card  10 B are essentially aligned along straight lines. The biometric smart card  1  and the enrolment card  10 B are also arranged such that the contact pins  18  face the contact pads  3 . 
     In this arrangement, the short edge portion of the biometric smart card  1  is placed above the first edge part  45 , above the third edge part  47 , and below the second edge part  46  of the enrolment card  10 B. Put differently, the short edge portion of the biometric smart card  1  is sandwiched between first edge part  45 , the third edge part  47 , and the second edge part  46 . The second edge part  46 , the first edge part  46 , and the third edge part  47  together press against the biometric smart card  1  in opposing directions to cause the contact pins  18  to contact the contact pads  3  firmly and properly. 
       FIGS. 10 and 11  show a further enrolment card  10 C, which is also a variant of the enrolment card  10 . 
     The enrolment cards  10 C and  10 B are similar. Differences between the enrolment card  10 C and the enrolment card  10 B relating to the card body are described below. 
     The enrolment card  10 C has a rectangular card body  12 C. The card body  12 C has a short edge  16 , a long edge that is essentially perpendicular to the short edge  16 , and a long edge portion  37  that is next to the long edge. The long edge portion  37  of the card body  12 C and the short edge portion  17  of the card body  12 B have similar parts, which are arranged similarly. Briefly, the long edge portion  37  of the card body  12 C includes a first edge part  45 , a first card reception opening  19 , a second edge part  46 , a second card reception opening  23 , and a third edge part  47 . 
     The card body  12 C also includes two parallel alignment lines  51 , which are marked on a front surface of the long edge portion  37 . The alignment lines  51  are essentially perpendicular to the long edge. The alignment lines  51  are spaced apart from each other by a predetermined distance, which is essentially same as a length of the short edge  6  of the biometric smart card  1 . The contact pins  18  are located between the alignment lines  51 . 
     The alignment lines  51  and the card reception openings  19  and  23  are intended for facilitating the engagement of the biometric smart card  1  with the enrolment card  10 C. 
     In use, as seen in  FIG. 12 , a user inserts the edge portion near the short edge  6  of the biometric smart card  1  into the card reception openings  19  and  23  of the enrolment card  10 C such that the edge portion of the biometric smart card  1  is sandwiched between the first edge part  45 , the third edge part  47 , and the second edge part  46  of the card body  12 C. The user then arranges the biometric card  1  until long edges of the biometric smart card  1  are essentially aligned with the alignment lines  51 , wherein the alignment lines  51  are substantially covered by the biometric smart card  1  and are almost invisible to the user. This allows the contact pads  3  to contact the corresponding contact pins  18  easily. 
     Different implementations of the card reception openings  19  and  23  are possible. The curved side edge  39  of the respective card reception openings  19  and  23  can be a straight edge. Similarly, the curved side edge  43  can also be a straight edge. The number of the openings can also be one only. 
     Instead of the display unit  21 , the display unit  21  can be replaced by a plurality of multi-colour light emitting diodes (LEDs). The colour LEDs are configured to display colour light, such as green, red, or yellow for indicating status of progress of the enrolment of the biometric smart card. For examples, LEDs can emit yellow light to indicate the enrolment being progressing, emit red light to indicate the enrolment being not successful, or emit green light to indicate the enrolment being complete. The colour LEDs can also be configured to emit different colour patterns to indicate the status of progress of the enrolment of the biometric smart card, such as first flashing or blinking green light for indicating commencement of the enrolment, or second blinking green light for indicating the enrolment being complete. 
     In one embodiment, the enrolment card  10  is configured to communicate wirelessly with a biometric smart card that is provided with an NFC device using NFC communication protocol. The NFC device can include an antenna that is electrically or communicatively connected to the microcontroller unit  8  of the biometric smart card. The enrolment microcontroller unit  15  of the enrolment card  10  is configured to communicatively connect with an antenna, such as a loop antenna according to ISO/IEC 14443-1. The antenna acts to transfer power or energy to the biometric smart card, as well as to enable data transmission between the biometric smart card and the enrolment card  10 . 
     The enrolment card  10  provides several benefits. 
     The enrolment card  10  is provided in a standard credit card size, which can be easily distributed to users. The users can perform self-enrolment of biometric smart card  1  remotely anytime and anywhere using the enrolment card  10 , thereby eliminating the inconveniences of visiting banks or premises that are authorized by the banks for enrolment of the biometric smart card  1 . 
     Since the enrolment card  10  has a shape and a size of a credit card that is similar to the biometric smart card  1 , the enrolment card  10  and the biometric smart card  1  can be produced using a same machine in a similar manner by a manufacturer. This allows the enrolment card to be produced at lower cost compared to other biometric enrolment devices, which often have form factors or physical specifications that are different from the credit card. 
     Furthermore, the enrolment card  10 , together with the biometric smart card  1 , can be conveniently delivered to a user using, for example, a mailing letter. 
     Moreover, the enrolment card  10  includes card engagement features, such as card reception openings  19  and  23 , for quick and easy alignment between the enrolment card  10  and the biometric smart card  1  such that the contact pins  18  of the enrolment card  10  contact the contact pads  3  of the biometric smart card  1 , thereby enabling the user to perform self-enrolment of the biometric smart card  1  easily and efficiently. 
     The embodiments can also be described with the following lists of features or elements being organized into an item list. The respective combinations of features, which are disclosed in the item list, are regarded as independent subject matter, respectively, that can also be combined with other features of the application.
     1. A biometric enrolment setup comprising
       a biometric card and   an enrolment card for transferring fingerprint biometric information of a user to the biometric card,   wherein the biometric card comprises   a plurality of contact pads,   a fingerprint sensor,   a first microcontroller unit being electrically connected to the contact pads and to the fingerprint sensor, and   a first card body, wherein the fingerprint sensor and the first microcontroller unit are embedded in the first card body,   the enrolment card comprises   a battery for providing electrical power,   a second microcontroller unit being electrically connected to the battery,   a plurality of contact pins being electrically connected to the battery and to the second microcontroller unit, and   a second card body with a card engagement element, the second card body being sized to correspond to the first card body,   wherein the battery and the second microcontroller unit are embedded in the second card body such that the second card body encloses the battery and the second microcontroller unit,   the biometric enrolment setup provides an enrolment mode, in the enrolment mode,   the card engagement element of the second card body engages with the first card body for allowing the contact pins of the enrolment card to contact the corresponding contact pads of the biometric card,   the battery provides the electrical power to the first microcontroller unit,   the fingerprint sensor obtains fingerprint biometric information of the user, and   the first microcontroller unit generates a reference fingerprint biometric template according to the fingerprint biometric information and stores the reference fingerprint biometric template.   
       2. The biometric enrolment setup according to item 1, wherein the second card body of the enrolment card comprises an inlay, the inlay comprises a stack of plastic sheets and at least one hole provided within the stack of plastic sheets for receiving the battery and/or the second microcontroller unit.   3. The biometric enrolment setup according to item 1 or 2, wherein the card engagement element comprises a fingerprint opening.   4. The biometric enrolment setup according to item 3, wherein the card engagement element further comprises a card fixing friction opening for preventing the contact pins from moving with respect to the corresponding contact pads.   5. The biometric enrolment setup according to item 1, wherein the second card body is provided with a rectangular shape.   6. The biometric enrolment setup according to item 5, wherein the card engagement element comprises at least one card reception opening being provided on an edge portion of the second card body.   7. The biometric enrolment setup according to item 6, wherein the edge portion is provided near a short edge of the second card body.   8. The biometric enrolment setup according to item 6, wherein the edge portion is provided near a long edge of the second card body.   9. The biometric enrolment setup according to item 8, wherein
       the card engagement element further comprises at least one alignment line for positioning the first card body with respect to the second card body.   
       10. The biometric enrolment setup according to one of items 1 to 9, wherein the enrolment card further comprises a low power means for configuring the second microcontroller unit into a low power mode.   11. The biometric enrolment setup according to item 10, wherein
       the low power means comprises a wire that connects a low power terminal of the second microcontroller unit to an electrical ground.   
       12. An enrolment card for a biometric card with a first card body, the enrolment card comprising
       a battery for providing electrical power,   a microcontroller unit being electrically connected to the battery,   a plurality of contact pins being electrically connected to the battery and to the microcontroller unit, and   a second card body with a card engagement element, the second card body being sized to correspond to the first card body,   wherein the battery and the microcontroller unit are embedded in the second card body such that the second card body encloses the battery and the microcontroller unit,   the enrolment card provides an enrolment mode, in the enrolment mode,   the card engagement element engages with the first card body for allowing the contact pins to contact corresponding contact pads of the biometric card,   the battery provides the electrical power to the biometric card.   
       13. The enrolment card according to item 12, wherein the second card body comprises an inlay, the inlay comprises a stack of plastic sheets and at least one hole provided within the stack of plastic sheets for receiving the battery and/or the microcontroller unit.   14. The enrolment card according to item 12 or 13, wherein the card engagement element comprises a fingerprint opening.   15. The enrolment card according to item 14, wherein the card engagement element further comprises a card fixing friction opening for preventing the contact pins from moving with respect to the corresponding contact pads.   16. The enrolment card according to item 12, wherein the second card body is provided with a rectangular shape.   17. The enrolment card according to item 16, wherein the card engagement element comprises at least one card reception opening being provided on an edge portion of the second card body.   18. The enrolment card according to item 17 wherein the edge portion is provided near a short edge of the second card body.   19. The enrolment card according to item 17, wherein the edge portion is provided near a long edge of the second card body.   20. The enrolment card according to item 19, wherein the card engagement element further comprises at least one alignment line for positioning the first card body with respect to the second card body.   21. The enrolment card according to one of items 12 to 20 further comprising a low power means for configuring the microcontroller unit into a low power mode.   22. The enrolment card according to item 21, wherein the low power means comprises a wire that connects a low power terminal of the microcontroller unit to an electrical ground.   23. A biometric card comprising
       a plurality of contact pads,   a fingerprint sensor,   a microcontroller unit being electrically connected to the contact pads and to the fingerprint sensor, and   a card body, wherein the fingerprint sensor and the microcontroller unit are embedded in the card body,   wherein the contact pads are configured to receive electrical power from a battery of an enrolment card, the fingerprint sensor is configured to obtain fingerprint biometric information of a user, and the microcontroller unit is configured to generate a reference fingerprint biometric template according to the obtained fingerprint biometric information and to store the reference fingerprint biometric template.   
       24. A method for enrolment of a biometric card using an enrolment card comprising
       engaging a card engagement element of the enrolment card with the biometric card for allowing contact pins of the enrolment card to contact corresponding contact pads of the biometric card,   providing electrical power by a battery of the enrolment card to a microcontroller unit of the biometric card,   obtaining fingerprint biometric information of a user by a fingerprint sensor of the biometric card,   generating a reference fingerprint biometric template according to the obtained fingerprint biometric information by the microcontroller unit of the biometric card, and   storing the generated reference fingerprint biometric template in the microcontroller unit of the biometric card.   
       25. A biometric enrolment setup comprising
       a biometric card and   an enrolment card for transferring fingerprint biometric information of a user to the biometric card,   wherein the biometric card comprises   a first antenna,   a fingerprint sensor,   a first microcontroller unit being electrically connected to the first antenna and to the fingerprint sensor, and   a first card body,   wherein the fingerprint sensor, the first microcontroller unit, and the first antenna are embedded in the first card body,   the enrolment card comprises   a battery for providing electrical power,   a second microcontroller unit being electrically connected to the battery,   a second antenna being electrically connected to the second microcontroller unit, and   a second card body,   wherein the battery, the second microcontroller unit, and the second antenna are embedded in the second card body such that the second card body encloses the battery, the second microcontroller unit, and the second antenna,   the biometric enrolment setup provides an enrolment mode, in the enrolment mode,   the second microcontroller unit receives the electrical power from the battery,   the second microcontroller unit powers the second antenna for communicatively connecting the second antenna with the first antenna,   the second antenna transmits the electrical power to the first microcontroller unit,   the fingerprint sensor obtains fingerprint biometric information of a user, and   the first microcontroller unit generates a reference fingerprint biometric template according to the obtained fingerprint biometric information and stores the reference fingerprint biometric template.   
       26. The biometric enrolment setup according to item 25, wherein the second card body comprises an inlay, the inlay comprises a stack of plastic sheets and at least one hole provided within the stack of plastic sheets for receiving the battery and/or the second microcontroller unit.   27. The biometric enrolment setup according to item 25 or 26, wherein the enrolment card further comprises
       a low power means for configuring the second microcontroller unit into a low power mode.   
       28. The biometric enrolment setup according to item 27, wherein
       the low power means comprises a wire that connects a low power terminal of the second microcontroller unit to an electrical ground.   
       29. An enrolment card for a biometric card with a first antenna, the enrolment card comprising
       a battery for providing electrical power,   a microcontroller unit being electrically connected to the battery,   a second antenna being electrically connected to the microcontroller unit, and   a card body,   wherein the battery, the microcontroller unit, and the second antenna are embedded in the card body such that the card body encloses the battery, the microcontroller unit, and the second antenna, the enrolment card provides an enrolment mode, in the enrolment mode,   the microcontroller unit receives the electrical power from the battery,   the microcontroller unit powers the second antenna for communicatively connecting with the first antenna, and   the second antenna transmits the electrical power to a microcontroller unit of the biometric card.   
       30. The biometric enrolment setup according to item 29, wherein the second card body comprises an inlay, the inlay comprises a stack of plastic sheets and at least one hole provided within the stack of plastic sheets for receiving the battery and/or the microcontroller unit.   31. The enrolment card according to item 29 or 30 further comprising
       a low power means for configuring the microcontroller unit into a low power mode.   
       32. The enrolment card according to item 31, wherein the low power means comprises a wire that connects a low power terminal of the microcontroller unit to an electrical ground.   33. A biometric card comprising
       an antenna,   a fingerprint sensor,   a microcontroller unit being electrically connected to the antenna and to the fingerprint sensor, and   a card body, wherein the fingerprint sensor, the microcontroller unit, and the antenna are embedded in the card body such that the card body encloses the fingerprint sensor, the microcontroller unit, and the antenna,   
       

     wherein the antenna is configured to receive electrical power from a battery of an enrolment card, the fingerprint sensor is configured to obtain fingerprint biometric information of a user, and the microcontroller unit is configured to generate a reference fingerprint biometric template according to the obtained fingerprint biometric information and to store the reference fingerprint biometric template. 
     Although the above description contains much specificity, this should not be construed as limiting the scope of the embodiments but merely providing illustration of the foreseeable embodiments. The above stated advantages of the embodiments should not be construed especially as limiting the scope of the embodiments but merely to explain possible achievements if the described embodiments are put into practice. Thus, the scope of the embodiments should be determined by the claims and their equivalents, rather than by the examples given. 
     REFERENCE NUMBERS 
     
         
         
           
               1  biometric smart card 
               2  card body 
               3  contact pads 
               3   a  GND contact pad 
               3   b  VCC contact pad 
               3   c  GPIO contact pad 
               4  contact pad module 
               5  fingerprint sensor 
               6  short edge 
               8  card microcontroller unit 
               10  enrolment card 
               10 A enrolment card 
               10 B enrolment card 
               10 C enrolment card 
               12  card body 
               12 A card body 
               12 B card body 
               12 C card body 
               13  fingerprint opening 
               14  card fixing friction cut-out 
               15  enrolment microcontroller unit 
               16  short edge 
               17  short edge portion 
               18  contact pins 
               18   a  GND contact pin 
               18   b  VCC contact pin 
               18   c  GPIO contact pins 
               19  card reception opening 
               20  wire 
               21  display unit 
               23  card reception opening 
               24  battery 
               27  NFC tag 
               28  contact pin module 
               29  dotted line 
               30  QR code 
               32  recess 
               33  contact pin pressing area 
               35  base 
               37  long edge portion 
               39  first side edge 
               43  second side edge 
               45  first edge part 
               46  second edge part 
               47  third edge part 
               51  alignment line