U.S. patent application number 15/371527 was filed with the patent office on 2017-09-28 for fingerprint sensor module.
This patent application is currently assigned to Fingerprint Cards AB. The applicant listed for this patent is Fingerprint Cards AB. Invention is credited to Mats Slottner.
Application Number | 20170277936 15/371527 |
Document ID | / |
Family ID | 59770420 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170277936 |
Kind Code |
A1 |
Slottner; Mats |
September 28, 2017 |
FINGERPRINT SENSOR MODULE
Abstract
It is provided a fingerprint sensor module comprising: a
substrate; a fingerprint sensing device mounted on a first side of
the substrate; at least one connection pad arranged on the
substrate and configured to electrically connect the fingerprint
sensor module to an external component; and an electrically
conductive layer arranged on a second side of the substrate,
opposing the first side, forming a back surface of the fingerprint
sensing module, wherein the electrically conductive layer is
connected to control circuitry of the fingerprint sensor module for
controlling a potential of a finger in contact with the
electrically conductive layer. There is also provided a smart card
comprising a fingerprint sensor module.
Inventors: |
Slottner; Mats; (LERUM,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fingerprint Cards AB |
Goteborg |
|
SE |
|
|
Assignee: |
Fingerprint Cards AB
Goteborg
SE
|
Family ID: |
59770420 |
Appl. No.: |
15/371527 |
Filed: |
December 7, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06K 9/00087 20130101;
G06K 9/00053 20130101; G06K 9/0002 20130101 |
International
Class: |
G06K 9/00 20060101
G06K009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2016 |
SE |
1650394-8 |
Claims
1. A fingerprint sensor module comprising: a substrate; a
fingerprint sensing device mounted on a first side of the
substrate; at least one connection pad arranged on the substrate
and configured to electrically connect the fingerprint sensor
module to an external component; and an electrically conductive
layer arranged on a second side of the substrate, opposing the
first side, forming a back surface of the fingerprint sensing
module, wherein the electrically conductive layer is connected to
control circuitry of the fingerprint sensor module for controlling
a potential of a finger in contact with the electrically conductive
layer.
2. The sensor module according to claim 1, further comprising a
cover layer arranged on the substrate covering a portion of the
substrate to encapsulate at least a portion of the fingerprint
sensing device.
3. The sensor module according to claim 2, wherein the at least one
connection pad is arranged on the first side of the substrate, and
wherein the cover layer does not cover the at least one connection
pad.
4. The sensor module according to claim 3, wherein the at least one
connection pad is arranged adjacent to an edge of the
substrate.
5. The sensor module according to claim 2, wherein a shape of the
cover layer is the same as a shape of the substrate, and wherein an
area of the cover layer is smaller than an area of the
substrate.
6. The sensor module according to claim 2, wherein a center of the
cover layer is aligned with a center of the substrate.
7. The sensor module according to claim 1, wherein the at least one
connection pad is arranged on the second side of the substrate, and
galvanically isolated from the conductive layer.
8. The sensor module according to claim 1, wherein the control
circuitry is configured to provide a drive signal or ground
potential to the electrically conductive layer.
9. The sensor module according to claim 1, wherein the electrically
conductive layer is connected to the control circuitry by means of
a via connection through the substrate.
10. The sensor module according to claim 1, wherein the
electrically conductive layer is a metal layer.
11. The sensor module according to claim 1, wherein the
electrically conductive layer is patterned.
12. The sensor module according to claim 1, further comprising a
coating layer arranged on the fingerprint sensing device.
13. The sensor module according to claim 12, wherein the coating
layer is colored.
14. The sensor module according to claim 12, wherein the coating
layer comprises a pattern.
15. A smart card comprising smart card circuitry and a sensor
module according to claim 1, wherein the smart card comprises an
opening in which the sensor module is arranged and wherein the
fingerprint sensor module is electrically connected to the smart
card circuitry via a connection point arranged in contact with the
connection pad of the sensor module.
16. The smart card according to claim 15, comprising: a first layer
comprising a first opening having a size and shape corresponding to
the cover layer of the sensor module; a second layer comprising a
second opening, larger than the first opening and having a size and
shape corresponding the substrate of the sensor module; and a
conductive layer comprising the connection point, arranged between
the first layer and the second layer, wherein the sensor module is
arranged such that a connection pad of the sensor module makes
contact with the connection point of the smart card.
17. The smart card according to claim 16, wherein an outer surface
of the first layer of the smart card is in the same plane as a
sensing surface of the sensor module; and an outer surface of the
second layer of the smart card is in the same plane as the
electrically conductive layer of the sensor module.
18. A smart card comprising smart card circuitry and a sensor
module according to claim 1, wherein the smart card comprises a
recess in which the sensor module is arranged such that the
fingerprint sensing device is covered by a first layer of said
smart card; and wherein the fingerprint sensor module is
electrically connected to the smart card circuitry via a connection
point arranged in contact with the connection pad of the sensor
module.
Description
FIELD
[0001] The present invention relates to a fingerprint sensing
module, and to a smart card comprising such a fingerprint sensing
module.
BACKGROUND
[0002] Various types of biometric systems are used more and more in
order to provide for increased security and/or enhanced user
convenience.
[0003] In particular, fingerprint sensing systems have been adopted
in, for example, consumer electronic devices, thanks to their small
form factor, high performance, and user acceptance.
[0004] Among the various available fingerprint sensing principles
(such as capacitive, optical, thermal etc.), capacitive sensing is
most commonly used, in particular in applications where size and
power consumption are important issues. All capacitive fingerprint
sensors provide a measure indicative of the capacitance between
each of several sensing structures and a finger placed on or moved
across the surface of the fingerprint sensor.
[0005] To accurately measure the capacitance between the finger and
a sensing structure, it is desirable that the finger can be held at
a known reference potential. In commonly available used in
smartphones and the like, the reference potential can be provided
by means of an electrically conductive bezel arranged around the
fingerprint sensor, where a finger placed on the sensor also
contacts the bezel.
[0006] However, for fingerprint sensor integration in smart cards,
which is increasingly requested by the market, the requirements of
the fingerprint sensor may change compared to when the sensor is
used in a smartphone. For example, a bezel involves an individual
manufacturing step and also adds steps to the assembly of the
fingerprint sensor, thereby adding to the cost of the fingerprint
sensor. Since the cost of a smartcard is significantly lower than
the cost of smartphone, it is advantageous to also reduce the cost
of the fingerprint sensor for a smart card. Furthermore, a rigid
metal bezel cannot be incorporated in a flexible smart card.
[0007] Accordingly there is a need for an improved fingerprint
sensor for integration in a smart card. In particular, there is a
need for a fingerprint sensor where a controlled reference
potential con be provided to a finger without the use of a
bezel.
SUMMARY
[0008] In view of above-mentioned and other drawbacks of the prior
art, it is an object of the present invention to provide a
fingerprint sensing module suitable for integration in a smart
card. In particular, the present invention relates to a fingerprint
sensing module where a reference potential can be provided to a
finger without the use of a bezel, and to a smart card comprising
such a fingerprint sensing module.
[0009] According to a first aspect of the invention, it is provided
a fingerprint sensor module comprising: a substrate; a fingerprint
sensing device mounted on a first side of the substrate; at least
one connection pad arranged on the substrate and configured to
electrically connect the fingerprint sensor module to an external
component; and an electrically conductive layer arranged on a
second side of the substrate, opposing the first side, forming a
back surface of the fingerprint sensing module, wherein the
electrically conductive layer is connected to control circuitry of
the fingerprint sensor module for controlling a potential of a
finger in contact with the electrically conductive layer.
[0010] The substrate on which the fingerprint sensing device is
mounted may be a conventional PCB substrate, a silicon substrate,
or any other type of substrate acting as a carrier for the
fingerprint sensing device. For example, the substrate may be a
flexible substrate, facilitating integration of the fingerprint
sensing module in a smart card, where a certain degree of
flexibility may be required.
[0011] The fingerprint sensing device can be a capacitive sensing
device, where a fingerprint image is captured by determining the
capacitive coupling between sensing structures of the sensing
device and a finger placed on a sensing surface of the sensing
device, where a fingerprint image is acquired by the specific
readout circuitry. The readout circuitry may be fully or partially
integrated in the same chip as the sensing circuit, or the readout
circuitry may comprise circuitry arranged separately from the
fingerprint sensing device.
[0012] Moreover, the control circuitry is configured to provide a
potential reference signal to the conductive layer, to control the
potential of a finger in contact with the sensing surface.
[0013] The present invention is based on the realization that a
fingerprint sensor module suitable for use in a smart card can be
provided by arranging an electrically conductive layer on a
backside side of a substrate, such that the potential of a finger
can be controlled without the use of a bezel. Thereby, when the
fingerprint sensing module is gripped with two fingers, e.g. the
thumb and the index finger, one finger will be in contact with a
sensing surface of the fingerprint sensing device and the other
finger will be in contact with the electrically conductive layer.
This allows the potential of the finger in contact with the sensing
surface to be controlled, which in turn facilitates fingerprint
capture. The described fingerprint sensor module can advantageously
be integrated in a smart card, as will be discussed in further
detail in the following.
[0014] Accordingly, a fingerprint sensor module is provided where
there is no need for a bezel or a similar conductive structure on
the same side as the fingerprint sensor, thereby simplifying the
construction of the fingerprint sensor module.
[0015] According to one embodiment of the invention the sensor
module may further comprise a cover layer arranged on the substrate
covering a portion of the substrate to encapsulate at least a
portion of the fingerprint sensing device.
[0016] In the present context, the cover layer may be an overmold
layer arranged to cover and protect the fingerprint sensor. The
cover layer may also be a stack of layers comprising additional
layers such as a protective plate, and adhesive etc. The cover
layer may also be arranged to cover only portions of the
fingerprint sensing device, such as the edges of the device
comprising bond pads and bond wires, in which case a separate layer
or structure may be used to protect sensing structures of the
fingerprint sensing device.
[0017] According to one embodiment of the invention, the at least
one connection pad may be arranged on the first side of the
substrate, and wherein the cover layer does not cover the at least
one connection pad. The connection pad would thus be arranged on
the same side of the substrate as the fingerprint sensing device,
facing in the same direction. Moreover, the connection pad is not
covered by a cover layer, meaning that the connection pad is
exposed to enable a connection to an external component such as a
smart card.
[0018] According to one embodiment of the invention, the at least
one connection pad may be arranged adjacent to an edge of the
substrate, thereby facilitation the connection between the sensor
module and an external component. It is not always required that
the connection pad is arranged directly adjacent to the edge of the
substrate. It may in some embodiments be sufficient that the
connection pad is arranged on the first side of the substrate
somewhere between the fingerprint sensing device and the edge of
the substrate. Moreover, it may also be possible to arrange the
connection pad on the edge of the substrate, i.e. on the side of
the substrate.
[0019] According to one embodiment of the invention, a shape of the
cover layer is the same as a shape of the substrate, and wherein an
area of the cover layer is smaller than an area of the substrate.
Moreover, the center of the cover layer may be aligned with a
center of the substrate. As an example, the sensor module may
comprise a rectangular substrate, having a rectangular fingerprint
sensing device with a rectangular cover layer arranged thereon. One
or more connection pads may thus be arranged adjacent to the edges
of the substrate, where they are exposed and not covered by the
cover layer.
[0020] According to one embodiment of the invention, the at least
one connection pad may be arranged on the second side of the
substrate, and galvanically isolated from the conductive layer. The
connection pad may thus be located on the same side as the
electrically conductive layer, which provides additional
integration possibilities of the sensor module.
[0021] In one embodiment of the invention, the control circuitry
may be configured to provide a drive signal and/or ground potential
to the electrically conductive layer. Assuming that the sensor
module is gripped with two fingers, where one finger is in contact
with the conductive layer and the other finger is in contact with
the fingerprint sensing device, the potential of the finger in
contact with the sensing device is also controlled by the control
circuitry comprised in the sensor module. A further advantage of
eliminating the need for a bezel is that the sensor module can be
configured to take up a smaller surface area.
[0022] According to one embodiment of the invention, the
electrically conductive layer may be connected to the control
circuitry by means of a via connection through the substrate. In
case of a silicon substrate, the connection may be referred to as a
through-silicon via (TSV) connection. This allows the control
circuitry to be arranged at a distance from the electrically
conductive layer. For example, the control circuitry may be
separately arranged on the same side as the fingerprint sensing
device, or the control circuitry may be integrated in the
fingerprint sensing device.
[0023] According to one embodiment of the invention, the
electrically conductive layer may advantageously be a metal layer,
which both provides high conductivity and high resistance to wear
and tear. Moreover, the use of a metal allows conventional
deposition techniques to be used, such as electroplating,
evaporation, sputtering etc.
[0024] Moreover, the electrically conductive layer may be
patterned, allowing the aesthetic outlook of the electrically
conductive layer to be tailored to accommodate different
requirements, in turn facilitating integration of the sensor module
in a wide range of applications.
[0025] According to one embodiment of the invention, the sensor
module may further comprise a coating layer arranged on the
fingerprint sensing device, and/or on the cover layer. The coating
layer could then be the outermost layer of the sensor module,
forming a sensing surface. A coating layer may for example be used
to give the sensor module a desired color or pattern, or the
coating layer could be a hydrophobic and/or oleophobic layer
preventing dirt from adhering to the sensor surface.
[0026] According to one embodiment of the invention, there is
further provided a smart card comprising smart card circuitry and a
sensor module according to any one of the above described
embodiments, wherein the smart card comprises an opening in which
the sensor module is arranged and wherein the fingerprint sensor is
electrically connected to the smart card circuitry via a connection
point arranged in contact with the connection pad of the sensor
module.
[0027] As a card is typically gripped with two fingers, this can be
utilized to control the potential of the fingers by means of an
electrode arranged on the backside of the fingerprint sensor such
that when a person grip the card and puts one finger on the sensor,
another finger will be in contact with the electrode and the
potential of the fingers can thereby be controlled.
[0028] The sensor module can thus be used to authenticate a user of
a smart card, and information relating to the authentication can be
provided to the smart card circuitry by means of the connection pad
of the sensor module and a corresponding connection point of the
smart card.
[0029] According to one embodiment of the invention, the smart card
comprises a first layer comprising a first opening having a size
and shape corresponding to the cover layer of the sensor module; a
second layer comprising a second opening, larger than the first
opening and having a size and shape corresponding the substrate of
the sensor module; and a conductive layer comprising the connection
point, arranged between the first layer and the second layer,
wherein the sensor module is arranged such that a connection pad of
the sensor module makes contact with the connection point of the
smart card. The opening of the first layer may also have a size
corresponding to the fingerprint sensing device of the sensing
module.
[0030] According to one embodiment of the invention, an outer
surface of the first layer of the smart card is located in the same
plane as a sensing surface of the sensor module; and an outer
surface of the first layer of the smart card is located in the same
plane as the electrically conductive layer of the sensor module.
Thereby, the sensor module can be integrated in plane with a smart
card without interrupting the smart card surface profile.
[0031] According to one embodiment of the invention, there is
provided a smart card comprising smart card circuitry and a sensor
module according to any one of the above described embodiments,
wherein the smartcard comprises a recess in which the sensor module
is arranged such that the fingerprint sensing device is covered by
a first layer of said smart card; and wherein the fingerprint
sensor module is electrically connected to the smart card circuitry
via a connection point arranged in contact with the connection pad
of the sensor module.
[0032] The sensing module can thereby be hidden as seen from a
first side of the smart card, and the fingerprint may be acquired
by placing the finger on the surface of the smart card at the
appropriate position corresponding to the position of the sensor
module, which for example may be visually indicated on the smart
card surface. Moreover, by integrating the electrically conductive
layer in the backside of the smart card, the sensor module can be
fully and seamlessly integrated in the smart card.
[0033] Further features of, and advantages with, the present
invention will become apparent when studying the appended claims
and the following description. The skilled person realize that
different features of the present invention may be combined to
create embodiments other than those described in the following,
without departing from the scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] These and other aspects of the present invention will now be
described in more detail, with reference to the appended drawings
showing an example embodiment of the invention, wherein:
[0035] FIG. 1 schematically illustrates a smart card comprising a
fingerprint sensor module according to an embodiment of the
invention;
[0036] FIGS. 2A-C schematically illustrate a sensor module
according to an embodiment of the invention;
[0037] FIG. 3 schematically illustrate a smart card comprising a
sensor module according to an embodiment of the invention;
[0038] FIGS. 4A-C schematically illustrate a sensor module
according to an embodiment of the invention;
[0039] FIGS. 5A-B schematically illustrate smart cards comprising a
sensor modules according to embodiments of the invention; and
[0040] FIG. 6 schematically illustrates a smart card comprising a
sensor module according to an embodiment of the invention.
DETAILED DESCRIPTION
[0041] In the present detailed description, various embodiments of
the fingerprint sensor module according to the present invention
are mainly described with reference to a fingerprint sensor module
for integration in a smart card, and to a smart card comprising
such a sensor module. However, the sensor module may equally well
be integrated in components such as USB connectors, electronic keys
and key fobs, security tokens and similar components benefiting
from biometric verification functionality.
[0042] FIG. 1 is a schematic illustration of a smart card 100
comprising a sensor module 102 according to an embodiment of the
invention.
[0043] FIG. 2A illustrates a fingerprint sensor module 102
comprising a substrate 202 and a fingerprint sensing device 204
mounted on a first side of the substrate 202. A connection pad 206
is arranged on the first side of the substrate, facing in the same
direction as the fingerprint sensing device 204. The connection pad
206 is electrically connected to the fingerprint sensing device 204
to provide information of a captured fingerprint to circuitry
external to the sensor module 102, such as smart card circuitry.
The fingerprint sensing device 204 is encapsulated and protected by
a cover layer 208 arranged on the substrate 202. The cover layer
208 may for example be a mold layer, and the cover layer 208 may
also comprise a plurality of separate layers. The cover layer 208
here forms an outer surface, i.e. a sensing surface, of the sensor
module 102. However, the cover layer 208 may also be arranged to
cover only a portion of the fingerprint sensing device 204, such as
the area covered by the sensing elements 212, or a separate layer
may be arranged to protect only the sensing elements 212 of the
fingerprint sensing device 204. A separate layer arranged to
protect the sensing elements may for example be a colored coating
or a protective dielectric plate such as a cover glass.
[0044] The fingerprint sensing device 204 is here illustrated as a
capacitive sensing device 204 comprising an array of electrically
conductive sensing elements 212, where a difference in capacitive
coupling between fingerprint ridges and valleys of a finger placed
on the sensor module is utilized to capture a fingerprint.
[0045] The fingerprint sensor module 102 further comprises an
electrically conductive layer 210 arranged on a second side of the
substrate 202, opposing the first side, thereby forming a back
surface of the fingerprint sensing module 102. The electrically
conductive layer is connected to control circuitry of the
fingerprint sensor module 102 for controlling a potential of a
finger in contact with the electrically conductive layer 210. The
electrically conductive layer 210 can for example be a Cu layer
deposited by electroplating. The electrically conductive layer 210
may also be patterned to provide a desired aesthetic appearance,
where the patterning may be achieved through laser singulation,
lithography, plating etc. For example, the electrically conductive
layer 210 may be shaped as a logotype or any other pattern. The
fingerprint sensing device may also comprise an electrostatic
discharge (ESD) node (not shown) arranged on the same side of the
substrate as the fingerprint sensor 204, to protect the sensor from
electrostatic discharge.
[0046] FIG. 2B is a perspective view of the sensor module 102 more
clearly illustrating a plurality of connection pads 206 arranged
adjacent to edges of the substrate 202. Moreover, the cover layer
208 here has the same shape as the fingerprint sensing device 204
and the substrate 202, but a smaller size than the substrate 202,
thereby exposing the connection pads 206 at the edge of the
substrate 202. It should be noted that many different
configurations of the cover layer and the connection pads are
possible. Connection pads 206 may for example be arranged adjacent
to all four edges of the substrate 202. The cover layer 208 may
also be arranged to reach one or more of the side edges of the
substrate. Moreover, even though the substrate 202 is illustrated
herein as being a rectangular or square substrate 202, the shape of
the substrate may in principle be selected arbitrarily, such as a
circular or ellipsoid substrate. The substrate 202 may be a
conventional PCB-substrate or it may be a flexible substrate, such
as a polyimide substrate.
[0047] FIG. 2C illustrates the backside of the sensor module 102,
comprising the electrically conductive layer 210. The electrically
conductive layer 202 may be arranged to cover the entire side of
the substrate 202 opposed to the side where the fingerprint sensing
device 204 is arranged, or it may cover selected portions of the
substrate 202 as illustrated in FIG. 2C, as long as the conductive
layer 210 can be assumed to be in galvanic contact with a finger
(e.g. the index finger) when the sensor module 102 is gripped and
another finger (e.g. the thumb) is placed on the surface of the
fingerprint sensing device 204.
[0048] Possible configurations of the readout circuitry and the
control circuitry for providing a reference potential are well
known to the skilled person and will not be discussed in further
detail herein. Moreover, both the readout circuitry and the control
circuitry may be fully integrated in the fingerprint sensing device
204, or parts of the circuitry may be arranged as discrete
components on the substrate 202. The fingerprint sensor module 102
may also be provided as system-in-package (SIP) module where a
number of integrated circuits, for example representing the sensing
device and parts or all of the readout and control circuitry, are
enclosed in a single module. Furthermore, the sensor module may
comprise nodes for handling electrostatic discharge, ESD. Dedicated
contacts may for example be arranged on the first side of the
substrate to connect the finger to ESD circuitry.
[0049] FIG. 3 schematically illustrates a smart card 300 comprising
the sensor module 102 described above. A smart card should in the
present context be interpreted broadly to comprise any card
comprising embedded integrated circuits providing functionality. A
smart card may for example be a credit card, an access card or an
identification card.
[0050] The smart card 300 comprises a through-opening in which the
fingerprint sensor module 102 is arranged and the sensor module 102
is electrically connected to smart card circuitry (not shown) via a
connection point 304 arranged in contact with the connection pad
206 of the sensor module 102. Moreover, the smart card 300
comprises a first layer 306 comprising a first opening having a
size and shape corresponding to the cover layer 208 of the sensor
module 102 and a second layer 308 comprising a second opening,
larger than the first opening and having a size and shape
corresponding to the substrate 202 of the sensor module 102. As
illustrated here, first and second openings of the respective first
and second layers 306, 308 are aligned such that the sensor module
102 can be arranged in the openings. The smartcard 102 further
comprises an electrically conductive layer 310 which connects the
sensor module 102 to smart card circuitry. The electrically
conductive layer 310 may for example comprise a plurality of
conductive traces, each comprising a connection point 304 arranged
to individually contact a corresponding connection pad 206 of the
sensor module 102. An adhesive may be used to attach the sensor
module 102 to the smart card 300.
[0051] FIGS. 4A-C are schematic illustrations of another embodiment
of a fingerprint sensor module 402 with FIG. 4A showing a side
view, FIG. 4B showing a perspective view and FIG. 4C showing the
backside of the sensor module 402. Here, the connection pads 404
are arranged on the same side of the substrate 406 as the
electrically conductive layer 408, i.e. on the backside of the
sensor module 402. The sensor module 402 further comprises a
fingerprint sensing device 410 and a cover layer 412 covering the
fingerprint sensing device 410, to form a sensing surface of the
sensor module 402. Accordingly, the described fingerprint sensor
module 402 provides additional possibilities for integration in
smart card or in other components.
[0052] FIG. 5A schematically illustrates a smart card 500
comprising the above described sensor module 402. The smart card
comprises a first layer 502 and a second layer 504, and a
conductive layer 506 therebetween which may comprise a plurality of
conductive traces. In the smart card in FIG. 5A, an opening in the
first layer 502 is larger than a corresponding aligned opening in
the second layer 504 such that the connection pads 404 of the
sensor module 402 contacts connection points 508 of the smart card
500 when the sensor module 402 is arranged in the openings. Here,
the backside of the sensor module 402 comprising the conductive
layer 408 is slightly recessed with respect to the outer surface of
the second layer 506 of the smart card 500, while both sides of the
sensor module 402 still are accessible from both sides of the smart
card 500. A similar arrangement may be suitable when integrating
the sensor module in devices which are thicker than the sensor
module, where both sides of the sensor module may be recessed, i.e.
arranged in a recess such that the surfaces of the sensor module
are below corresponding surfaces of the device in which the sensor
module is arranged. Thereby, both sides of the sensor module are
accessible even if the device is considerably thicker than the
sensing module. Alternatively, or in combination, the thickness of
the substrate and/or of the fingerprint sensing device of the
sensor module may be adapted such that the overall thickness of the
sensor module correspond to the thickness of the device in which
the sensor module is to be arranged.
[0053] FIG. 5B schematically illustrates a smart card 510
comprising a sensor module 402 covered by a first layer 512 of the
smart card such that the sensor module 402 is hidden beneath the
surface of the smart card 510. The thickness of the first layer 512
at the location of the fingerprint sensing device 410 can be
adapted so that a fingerprint may be acquired through the first
layer 512.
[0054] The skilled person realizes that many combinations of the
above described embodiments are possible relating to on which side
of the sensor module the connection pads are located, how the
sensor module is integrated in the smart card and so on.
[0055] Furthermore, the sensor module may comprise a plurality of
connection pads arranged in different locations for enabling
connection of the module to different types of components, such as
smart cards, USB-tokens, car keys etc. Thereby, a sensor module can
be provided which can be used in a range of different applications
without the need for application specific modifications of the
sensor module.
[0056] FIG. 6 schematically illustrates a smart card 600 where the
substrate 602 forms a larger part of the overall smart card 600.
The substrate 602 may for example fully or partially replace the
second layer, i.e. the bottom layer, of the smart card 600. As
illustrated in FIG. 6, the first layer 604, i.e. the top layer, of
the smart card 600 is arranged on top of the substrate 602, and an
electrical contact is formed between a connection pad 606 of the
substrate 602 and a corresponding connection point 608 of the smart
card 600 to connect the sensor module 600 to smart card circuitry
610. Moreover, the first layer may be extended to cover the
fingerprint sensing device in a similar manner as described in
relation to FIG. 5B, thereby forming smart card with a fully
integrated sensor module.
[0057] Even though the invention has been described with reference
to specific exemplifying embodiments thereof, many different
alterations, modifications and the like will become apparent for
those skilled in the art. Also, it should be noted that parts of
the fingerprint sensor module may be omitted, interchanged or
arranged in various ways, the fingerprint sensor module yet being
able to perform the functionality of the present invention.
[0058] Additionally, variations to the disclosed embodiments can be
understood and effected by the skilled person in practicing the
claimed invention, from a study of the drawings, the disclosure,
and the appended claims. In the claims, the word "comprising" does
not exclude other elements or steps, and the indefinite article "a"
or "an" does not exclude a plurality. The mere fact that certain
measures are recited in mutually different dependent claims does
not indicate that a combination of these measures cannot be used to
advantage.
* * * * *