Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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RFID PROXIMITY CARD HOLDER WITH FLUX DIRECTING MEANS
FIELD OF THE INVENTION
[0001] The present invention relates to an RFID proximity card holder with
magnetic flux
directing means. In particular, there is provided an RFID proximity card
holder comprising a
magnetic flux directing means having a magnetic material for directing
magnetic flux generated
by a contactless interface to within the area of an RFID proximity card
antenna loop.
BACKGROUND OF THE INVENTION
[0002] RFID proximity cards, or contactless smartcards, have become a widely
used form of
contactless rechargeable type smartcard for intelligent access control and
payment systems,
particularly in the area of mass public transportation, where fast
transactions and ease of handling
are desired. The prevalent type of contactless smartcards used for such
systems are generally
powered by and communicate with a contactless interface, or a proximity card
reader, according
to resonant energy transfer operating principles. In particular, such near
field wireless
transmission of energy operates by producing an alternating magnetic field
generated by
sinusoidal current flowing through a card reader antenna loop such that an
RFID proximity card
within the alternating magnetic field will have an alternating current induced
in its loop antenna
to thereby supply power to the RFID smartcard circuitry. Typically, for such
operation, a
proximity card must be placed within a region of approximately zero to three
inches from a
reader and be parallel thereto such that the magnetic flux emitted by the
reader passes through the
antenna loop area of the proximity card. Consequentially, it is well known
that the quality of this
inductive coupling between the antennas of a reader and a proximity card is
critical to ensuring
quality energy transfer.
[0003] However, one drawback associated with such near field wireless energy
transmission
is that a sufficient electromagnetic flux passing through the card antenna
coil necessary to power
the smartcard electronics is only obtained when the proximity card has a well
defined orientation
relative to the flux lines generated by the reader. When the position of the
proximity card is
deviated from this optimal orientation, the flux passing through the area of a
card antenna loop
rapidly decreases thereby rendering the proximity card powerless and useless
until a sufficient
orientation is found. Proper positioning of a proximity card relative to the
lines of flux generated
by a reader may be especially difficult to attain and maintain in real world
operation, such as in
mass transit wherein commuters position cards over a reader at various angles
with their hands or
position bags and purses containing such cards. This drawback presents serious
repercussions,
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notably regarding high volume transaction situations, for example at mass
transit contactless card
reader stations located on bus or subway access points, wherein recognition of
an RFID proximity
card is needed to be accomplished in the shortest amount of time. Prolonged
reading times at a
contactless card reader station due to improper card orientation or distance
has a compounding
effect when multiple cards experience such problems, leading to increases in
boarding times and
ultimately disgruntle commuters.
[0004] Various manners to alleviate these drawbacks are known and involve
focusing and
concentrating magnetic flux to within the area of the antenna coil of a
proximity card to thereby
increase operating distance, reduce the effect of a less than optimal card
orientation with respect
to the reader, and ultimately improve the power transfer necessary for a
proximity card to operate.
In particular, it is generally known that employing a magnetic material for
manipulating the
magnetic flux generated by a card reader is able overcome these drawbacks.
[0005] Although the prior art teaches of a wide variety of such magnetic flux
focusing
means to improve the magnetic coupling between a card loop antenna and a
reader antenna to
thereby ensure a sufficient degree of flux is passed within a card antenna
loop area while at
different orientations and distances, current teachings of focusing means tend
towards the
integration of magnetic materials into the substrate of a proximity tag, with
the particular
objective of negating counter acting magnetic fields generated by eddy current
when an RFID tag
is in proximity to a metallic surface. Such integration, however, increases
the fabrication costs,
bulkiness, and weight of a RFID proximity card. Still, other teachings involve
shields comprising
magnetic materials being formed in a permanent manner to the substrate of a
proximity card.
However, due to the high failure rate of proximity cards, integrating magnetic
material within the
substrate of a proximity card may be costly, particularly for the mass
transportation market where
cards are easily lost and fail regularly due to the abuse endured from daily
handling.
[0006] Furthermore, some forms of contactless smartcards are a dual interface
type and
comprise an additional communication interface in the form of a mechanical
contact area
comprising metallic contacts on the face of a smartcard which are connected to
a microchip
embedded in the substrate body of the smartcard. Smartcards with these types
of interfaces may
to be physically inserted into a mechanical acceptance device to align these
contacts with the
contacts of a mechanical reader to thereby create a communication link.
[0007] What is therefore needed, and an object of the present invention, is a
flux directing
means for an RFID proximity card which enables improved interrogation
orientation deviation
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and reading distance of an RFID proximity smartcard by an RFID reader by
providing a magnetic
induction coupling enhancing means capable of being non-permanently
retrofitted to an existing
RFID proximity smartcard. In particular, the magnetic coupling means is able
to be removed
from the smartcard such that an RFID proximity smartcard may continue to be
employed with
existing mechanical contact reading machines for charging, reading, and the
like.
[0008] Still further, contactless smartcard durability is known to depend on
the quality of the
bond between the embedded antenna and a smartcard microcontroller. Such a bond
is prone to
breakage should a card be subjected to excessive bending and torsion flexing
when, notably, card
holders attempt to use their card by pressing the card on a card reader, and
from the daily
handling and storing of a card in a purse, pocket, wallet, bag, or the like.
Therefore, these factors
may impact or significantly reduce the readability and life span of an RFID
proximity smartcard.
[0009] What is therefore needed, and yet another object of the present
invention, is a non-
permanent smartcard holder that protects an RFID proximity card from day-to-
day wear and tear
and which simultaneously improves magnetic coupling between a card and a card
reader.
SUMMARY OF THE INVENTION
[0010] More specifically, in accordance with the present invention, there is
provided a card
holder for an RFID proximity card comprising a coil loop antenna with an area
for interfacing
with a flux generating RFID proximity card reader, the card holder comprising:
a flux directing
means; and a housing for containing said flux directing means and receiving
the RFID proximity
card; wherein when the RFID proximity card is received within said housing,
said flux directing
means influences the flux generated by the RFID proximity reader such that the
flux is directed to
within the area of the coil loop antenna.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the appended drawings:
[0012] FIG. I is a perspective view of a known contactless smartcard system;
[0013] FIG. 2 is a top cross-sectional view of an RFID proximity card of the
contactless
smartcard system of FIG. 1 taken along the line 1-1;
[0014] FIG. 3 is a top perspective view of an RFID proximity card holder with
flux directing
means in accordance with an illustrative embodiment of the present invention;
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[0015] FIG. 4 is a bottom perspective view of an RFID proximity card holder
with flux
directing means of FIG. 3;
[0016] FIG. 5 is a bottom perspective view of an RFID proximity card holder
with flux
directing means of FIG. 3 having a proximity card received therein;
[0017] FIG. 6 is a top cross-sectional view of a RFID proximity card of a
contactless
smartcard system of FIG. 1 taken along the line 1-1 illustrating the position
of a flux directing
means of FIG. 3;
[0018] FIG. 7 is a side view of the contactless smartcard system of FIG. 1
illustrating
magnetic flux passing through the antenna loop area of an RFID proximity card;
and
[0019] FIG. 8 is a side view of the contactless smartcard system of FIG. 1
illustrating
magnetic flux passing through the antenna loop area of an RFID proximity card
as directed by the
RFID proximity card holder with flux directing means of FIG. 3.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0020] Referring to FIG. 1, a contactless smartcard system in accordance with
an illustrative
embodiment of the present invention, generally referred to using the reference
number 10 is
described. In particular, the contactless smartcard system 10 comprises an
RFID proximity card
12 and a contactless interface 14, also generally known in the art as a card
reader or a card
interrogator, for powering and communicating with the proximity card 12.
Generally, the reader
14 comprises a reader antenna coil 16 that provides energy in the form of a
generated magnetic
flux 18 and/or for communication with an RFID proximity card 12 when brought
into proximity
with the reader 14, as well as electronics 20 to process validation and other
information
transmitted from the RFID proximity card 12. In accordance with the
illustrative embodiment of
the present invention, when the contactless smartcard system 10 is used for
public transit
applications, the reader 14 is commonly located in fare boxes, ticket
machines, turnstiles, and
station platforms as a standalone unit. In accordance with another
illustrative embodiment of the
present invention, when the contactless smartcard system 10 used for security
applications, the
reader 14 is usually located at the side of a door entrance.
[0021] Now referring to FIG. 2, in addition to FIG. 1, the RFID proximity card
12, used in
accordance with an illustrative embodiment of the present invention, comprises
a credit card
shaped substrate 22 with an RFID tag integrated therein. The RFID tag
comprises an antenna 24
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formed as a coil antenna disposed within the substrate 22 of the card 12, and
a computing device
or chip 26 comprising a smartcard secure microcontroller, or equivalent
intelligence, for
modulating and demodulating a radio-frequency (RF) signal for communication
with the reader
14 and processing information, along with an internal memory for storing
information. The RFID
tag further comprises additional electronics (not shown) embedded within the
substrate 22 to
convert an induced alternating current 28 to direct current to power up the
chip 26. Furthermore,
some forms of contactless RFID proximity cards 12 are a dual interface type
and comprise an
additional communication interface in the form of a mechanical contact area 30
on the face of the
smartcard 12 comprising metallic contacts connected to the chip 26. An RFID
proximity card 12
comprising a mechanical contact area 30 may be physically inserted into a
mechanical reader
device (not shown) to align the mechanical contact area 30 with the contacts
of the mechanical
reader to create a communication link between the card 12 and the mechanical
reader. During the
lifespan of the card 12, the chip 26 and associated memory will be loaded with
new information
from a contactless reader 14 or a non-contactless reader (not shown) via the
antenna 24, or via the
contact plates 30, respectively. Such information may include, for example,
transport rights or
transport tokens, which may be validated at a card reading station before
granting access to a
restricted network or area, for example a transport network, verified for
security or fraud
purposes, debited when transport tokens are purchased, or displayed to a
transport user to know
the status of the transport tokens remaining on the card 12.
[0022] Still referring to FIG. 2 in addition to FIG. 1, the dimensions of a
contactless smart
card 12, in accordance with an illustrative embodiment of the present
invention, approximate that
of a credit card. Specifically, the ID-1 of ISO/IEC 7810 standard defines such
dimensions as
85.60 mm (Length) x 53.98 mm (Width) x 0.76 mm (Thickness). The substrate 22
of the RFID
proximity card 12 may be illustratively formed from a flexible material such
as a dielectric
substrate having first and second generally parallel planar surfaces on
opposite sides thereof
which also conforms to such the ISO/IEC 7810 standard. Typically in transit
RFID proximity
card applications, one side of the card 12 may comprise the mechanical contact
area 30 while the
other side may comprise additional visual validation information 32, such as a
photo ID for
seniors or students who benefit from a reduced transit fare, along with
information such as the
name and address of the card holder (see FIG. 5). Within the substrate 22 is
integrated the
antenna 24 which receives energy inductively coupled from the card reader 14
and which also
transmits validation information thereto. Generally, the antenna 24 is
designed as a coil antenna
and comprises a sufficient number of turns (N) of a highly conductive
material, such as copper, so
it is sensitive to magnetic currents found in radio waves passing through its
antenna loop area 34.
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While there are a large number of loop antenna designs for the antenna 24, all
of which are aimed
at converting an electromagnetic wave into a voltage it should be understood
that, although the
present invention is described using N-Turn square loop coil antenna which is
as large as
practicable and consistent with the dimension requirements of the contactless
card 12, a variety of
other antenna types which meet dimension requirements of the contactless card
12, the resonating
inductance requirements for the chip 20 electronics, as well as the flux
collecting requirement
within the antenna loop area 34, may be employed.
[0023] Referring back to FIG. 1, the communication and powering of the
smartcard 12 is
achieved by interaction of the RFID proximity card 12 with the contactless
interface 14 in the
manner described herein below. In particular, such contactless smartcard
readers 14 use radio
frequencies to communicate with an RFID proximity card 12 to both read from
and write data to
the memory of the smart card 12. Power supplied via induction coupling with
the smartcard 12
comes from a 13.56 MHz alternating magnetic field 18 generated by the antenna
coil 16 of the
reader 14. The reader 14 also comprises the various electronics 20 for,
amongst other things,
controlling an alternating current 36 provided to generate the alternating
magnetic field 18 and
for modulating and demodulating signals received and transmitted to and from
the smartcard 12.
In operation of the contactless smartcard system 10, the RFID proximity card
12 is positioned
over the contactless reader 14 generally at a distance of approximately 0 to 3
inches, or to within
cm of the reader antenna 14. When the contactless smartcard 12 is brought
within proximity of
the card reader 14, the alternating magnetic field 18 is produced by a
sinusoidal current 36
flowing through the reader antenna loop 16. Once the RFID proximity card 12 is
correctly
positioned within the alternating magnetic field 18, the alternating current
28 is induced in the
card loop antenna 24.
[0024] Referring now to FIG. 3 and FIG. 4, an illustrative embodiment of an
RFID
proximity card holder with flux directing means, generally referred to using
the reference number
38, will now be described within the context of the contactless smartcard
system 10. The card
holder 38 comprises a body 40 adapted to receive an RFID proximity card 12,
and a flux
directing element 42 such that the flux directing element 42 is positioned
substantially centered
and above the plane parallel to the RFID proximity card loop antenna 24 when
the proximity card
12 is received therein. The body 40 may be composed of a non-metallic light
weight material
such as injection molded plastic or the like. Furthermore, the body 40
comprises an open bottom
44, a hollow raised top portion 46 for receiving the flux directing element
42, an open side end 48
and a closed side end 50, as well as first 52 and second sides 54 and a series
of protruding tabs 56
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extending inwardly from the closed side end 50, and the first 52 and second
sides 54. The body
40 further comprises a ring 58 or hook formed thereto through which a string
or an attachment
means 60 may be connected for securing the card holder 38 to an object, such
as a bag, an article
of clothing, or the like. The raised top portion 46 is illustratively embossed
with chevron like
gripping indentations 62 for providing traction to a holder's grip.
[0025] Referring now to FIG. 5 and FIG. 6, in addition to FIG. 3 and FIG. 4,
the RFID
proximity card holder with flux directing means 38 slidably receives the
totality of the RFID
proximity card 12 through its open side end 48 which is secured into place
therein by the series of
protruding tabs 56. The open side end 48 permits any validation information
32, such as a photo
ID printed on the side of card 12, to be viewable when the card 12 is received
within the card
holder 38, and without any obstruction by the series of protruding tabs 56 to
permit an additional
visual validation, for instance by a bus driver or an access station transmit
worker, to ensure the
identity of the card holder matches the validation information 32. Once the
card 12 is slid into the
card holder 38 it may snap or click into place in a non-permanent manner such
that the card 12 is
protected from flexing and torsion by the structural rigidity provided for by
the body 38. Such
structural reinforcement will protect the bond between the embedded loop
antenna 24 and the
chip 26 from breakage should the card 12 be subjected to excessive bending and
torsion flexing
when, notably, card holders attempt to use their card 12 by pressing it on a
card reader 14, and
from the daily handling and storing of a card 12 in a purse, pocket, wallet,
bag, or the like. Once
secured into place within the card holder 38, the card 12 may be removed
thereafter should the
card 12 be required to be inserted into a contact mechanical reading machine
or for storage in a
wallet or the like.
[0026] Referring back to FIG. 3 and FIG. 4, the flux directing element 42 is
comprised of a
planer layer of a magnetic material with a high permeability capable of
confining and guiding
magnetic flux 18. For instance, the flux directing element 42 is
illustratively composed of a
ferromagnetic metal such as iron or ferromagnetic compounds such as ferrites
having a high
permeability relative to the surrounding air, which makes it capable of
influencing the magnetic
field lines 18 to be concentrated within its core and ultimately within the
area antenna loop area
34. The flux directing element 42, while illustratively shaped as rectangular
cube, may take on
other forms as known to a person skilled in the art such that the magnetic
flux 18 is sufficiently
directed to within the antenna loop area 34. Additionally, the thickness of
the flux directing
element 42 may vary depending on different factors such as portability and
weight, as well as the
degree of influence the flux directing element 42 is designed to have on the
flux 18. For instance,
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a flux directing element 42 having a thinner thickness may be preferred for
lower cost, while a
thicker flux directing element 40 may be preferable for increased
interrogation distance.
[0027] Now referring to FIG. 7 and FIG. 8, in addition to FIG. 6, in operation
of the RFID
proximity card holder with flux directing means 38, an RFID proximity card 12
is slid into the
open side end 48 of the body 40 until it abuts the closed side end 50 and is
snapped securely into
place therein. Once the card 12 has been secured and is enclosed by the card
holder 38, the flux
directing element 42 is positioned relative to the loop antenna 24 such that
it is centered within
and above the antenna loop area 34 in a parallel plane. The high permeability
of the flux directing
element 42 relative to the surrounding air, causes the magnetic field lines
18A generated by the
reader 14, which would not ordinarily pass through the antenna loop area 34
absent a flux
directing element 42 as does the flux 18B, to be influenced and drawn into its
core to thereby
force the flux 18A passing in proximity to the card 12 to be concentrated
within the antenna loop
area 34 as a magnetic flux 18B. The increased flux 18B now focused to within
the antenna loop
area 34 allows a significant improvement in the magnetic coupling between the
loop antenna of
the RFID proximity card 12 and the reader antenna coil 16. Consequentially,
the user of a
proximity card 12 retrofitted with the RFID proximity card holder with flux
directing means 36
will provide a more convenient experience for a card holder since the reading
of the card 12 will
appear to occur sooner on approach to the card reader 14, at a greater
distance, and at less than
optimal orientations. Furthermore, should a card 12 have to be recharged in a
mechanical reading
device employing the mechanical contact area 30, the RFID proximity card 12 is
easily
removable from within the card holder 38 by simply sliding the card out of the
open side end 48.
[0028] In summary, the RFID proximity card holder 38 of the present invention
improves
and optimizes the interrogation orientation deviation and reading distance of
an existing RFID
proximity smartcard 12 by an RFID reader 14. The RFID proximity card holder 38
of the present
invention is also capable of being non-permanently retrofitted to the existing
RFID proximity
smartcard 12. In particular, the existing RFID smartcard 12 may continue to be
employed with
existing mechanical contact reading machines for charging, reading, and the
like that may require
that the RFID proximity smartcard 12 be removed from the card holder 38.
Furthermore, the non-
permanent smartcard RFID holder 38 according to the present invention protects
the RFID
proximity card 12 from day-to-day wear and tear and simultaneously improves
magnetic coupling
between the RFID proximity card 12 and the RFID card reader 14. The RFID card
holder 38 may
also include the raised-up area 46 that a user can more easily grasp on to and
which allows for
improved positioning of the RFID card 12 onto the RFID reader 14.
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[0029] Although the exemplary embodiments of the present invention are
discussed with
reference to RFID proximity smartcards used in the context of a mass public
transportation
system, other applications may include access control to buildings and other
forms of smartcards
such as student ID access cards, building access cards, taxis, tram ways,
subways, electronic toll
collection, security access or other types of payment systems, and it can be
modified, without
departing from the spirit and nature of the subject invention as defined in
the appended claims.
