Patent Publication Number: US-2012037706-A1

Title: Rfid proximity card holder with flux directing means

Description:
FIELD OF THE INVENTION 
     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 
     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. 
     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, 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. 
     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. 
     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. 
     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. 
     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 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. 
     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. 
     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 
     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 
       In the appended drawings: 
         FIG. 1  is a perspective view of a known contactless smartcard system; 
         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 ; 
         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; 
         FIG. 4  is a bottom perspective view of an RFID proximity card holder with flux directing means of  FIG. 3 ; 
         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; 
         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 ; 
         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 
         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 
     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. 
     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  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 . 
     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)×53.98 mm (Width)×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 . 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. 
     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 10 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 . 
     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  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&#39;s grip. 
     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. 
     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, 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. 
     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  18 A 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  18 B, to be influenced and drawn into its core to thereby force the flux  18 A passing in proximity to the card  12  to be concentrated within the antenna loop area  34  as a magnetic flux  18 B. The increased flux  18 B 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 . 
     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 . 
     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.