Abstract:
A radio operated data card whose outer jacket forms a sealed protected housing for internal electrical components, including an RFID integrated circuit which incorporates data storage and a radio frequency transceiver, an on card antenna, and manually operated, normally open electrical switch contacts connected between the on-card electronic circuitry and the antenna. The open switch contacts normally disable the card, protecting the data on the card from being surreptitiously read until the switch contacts are intentionally closed by the cardholder to enable data transfer to occur. The cardholder may activate the card by applying external pressure to the surface of the card at a predetermined position, closing the switch contacts which open again automatically when pressure is removed. A tactile indicia on the surface of the card allows the cardholder to determine by touch where the card should be pressed to enable data transfers to occur. In an alternate embodiment, a mating key in the possession of the cardholder may be brought into proximity with the card to close the normally open switch to permit information to be read from the card.

Description:
BACKGROUND OF THE INVENTION 
   Payment devices such as magnetic stripe-based credit cards may be targeted for theft and misuse. Readily available magnetic strip readers can be used by a thief to obtain account information from the card. Chip based cards that use electrical contacts to transfer information to and from a reader offer higher levels of security, and both magnetic strip and contact-bearing cards are further protected by the fact that the card must be in physical contact with the reader. 
   Contactless cards use radio signaling to exchange information with a host system, and offer substantial convenience since the card may be used without bringing it into direct contact with a reader. Developments in radio frequency identification (RFID) technology continue to yield larger memory capacities, wider reading ranges, and faster processing. RFID provides a powerful means of enhancing data handling processes, complimentary in many ways to other data capture technologies such as magnetic stripe. A range of RFID devices and associated systems are available to satisfy a broad range of applications. 
   However, because RF-enabled devices such payment cards can be read at a distance with a suitable transmitter and receiver, it is possible to surreptitiously obtain information from the card while it remains in its cardholder&#39;s possession. In addition to non-contact data transfer, wireless communication can also allow non-line-of-sight communication, meaning that an RF-enabled device may be read while it remains in the cardholder&#39;s wallet or purse. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention helps protect a contactless information storage device, such as an RFID payment card, from unauthorized misuse. The card employs an on-card antenna that couples integrated circuit electronics to a remote transmitter/reader. In accordance with the invention, the card incorporates an internal mechanism that normally disables the on-card electronic circuitry until the mechanism is intentionally actuated by the cardholder. The mechanism prevents the information on the card from being accessed until user activates the mechanism to enable signal transmission between the card and the remote unit. 
   The mechanism used to disable and enable the card must be flat enough to fit in the limited space available in a card meeting relevant ISO standards, must be robust enough to withstand stress and abuse, and must employ low-cost components and be easy to assemble and produce in quantity. In addition, the mechanism must not be potentially harmful to users due by introducing sharp or pointed edges, leak fluids, or contain a substance that might trigger allergic reactions. In addition, the mechanism employed should be functionally flexible in order to work in cards and other devices having a variety of shapes and sizes. Finally, the mechanism should be able to control the on-card electronics, typically a mass-produced integrated circuit chip, regardless of whether the chip is internally or externally powered. 
   The preferred embodiment of the invention takes the form of user-activated, normally open electrical switch contacts connected between the on-card electronic circuitry and an on-card antenna. Until the contacts are intentionally closed by the cardholder, the antenna is disconnected to prevent the card from transmitting or receiving information. After the user intentionally closes the switch contacts when the card is being used to provide information to an authorized remote reader/transmitter, the contacts automatically reopen to prevent the card from being accessed. 
   In a “passive” card which is powered by electrical energy induced in the antenna RF energy from the reader/transmitter, the card receives no power when the switch contacts are open. In an active circuit, the open switch contacts disable the card&#39;s ability to transmit by disconnecting the antenna from the on-card electronics. 
   The switching mechanism may advantageously take the form of normally spaced-apart electrical contacts positioned adjacent to one another within the card but held in a non-contacting relationship by a resilient material. When the cardholder presses on the surface of the card in a predetermined location, the outer surface of the card deflects, moving one of the two contacts into engagement with the other while deforming the resilient material. When the applied pressure is removed, the resilient material moves the contacts apart again, breaking the electrical connection, and disabling the card&#39;s ability to receive and transmit information via antenna. The electrical contacts may be positioned for sliding engagement with one another to provide a self-wiping action to ensure a good electrical connection. 
   The outer surface of the card adjacent to the switch contacts may be advantageously molded to form a resilient, a dome-shaped dimple that acts as a Belleville spring. The cardholder can feel the presence of the dimple on the card, providing a tactile indication to the cardholder of the place on the card which should be pressed to activate the card. In addition, when the dome-shaped dimple is depressed, it deforms to allow the cardholder to feel proprioceptive feedback as the switch closes. The chamber which enclosed by the dimple may be sealed except for one or more bleed apertures which permit a measured flow of air or fluid into and out of the chamber. When the dimple is depressed, the air is expelled through the bleed aperture. Then, when the cardholder releases the dimple, the air or fluid is returned into the chamber at a timed rate, creating a time delay before the switch contacts again open as the dimple returns to its normal shape. This same principle of an aperture can allow fluid to creep from one internal bladder to another in the card to allow the button to move and to be used as a timer as well. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       FIG. 1  is a top plan view of an RF-enabled payment card which employing a pressure-actuated manual switch for protecting the card against unauthorized use; 
       FIGS. 2 and 3  are cross-sectional views of the switch mechanism used in the payment card of card of  FIG. 1  shown in its normal and actuated states, respectively; 
       FIG. 4  is a top plan view of an RF-enabled payment card which employs a pressure-operated manual switch using a dome-shaped dimple on the card&#39;s surface to facilitate actuation of the switch; 
       FIGS. 5 and 6  are cross-sectional views of the switch mechanism used in the payment card of  FIG. 4  shown in its normal and actuated states, respectively; 
       FIG. 7  is a plan view of an RF-enabled payment card using magnetically actuated switch contacts and a key device for enabling the card; and 
       FIG. 8  is a plan view of an RF-enabled payment card which employs capacitive coupling by a matching key device for enabling the card. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   RF-enabled cards, identification tags, and the like (referred to as “cards” or “data cards”) carry data which typically identifies and relates to a specific person, a particular account, an individual vehicle, or an item, and further contains additional data supporting applications through item specific information or instructions immediately available on reading the card. 
   A RFID system requires, in addition to the data cards, a means of reading or interrogating the data cards and communicating the data between the card and a host computer or information management system (hereinafter referred to as a “reader”). Communication of data between the cards and a reader is achieved by wireless communication, either based upon close proximity electromagnetic or inductive coupling, or based upon propagating electromagnetic waves. Coupling is achieved using antenna structures forming an integral feature in both data cards and readers. As used here, the term “antenna” refers to both propagating systems as well as inductive systems. 
   Data storage and processing as well as RF communications functions are typically performed on the data card by one or more integrated circuit chips. For example, the SRIX4K Smartcard Chip available from STMicroelectronics is a integrates a power reception system which uses the received RF signal as a power source, an emitter/receiver module compatible with the ISO 14443 standard, together with an asynchronous 8-bit micro-controller. The chip contains a 4096-bit user EEPROM fabricated with CMOS technology and stores data in 128 blocks of 32 bits each. The SRIX4K is accessed via the 13.56 MHz carrier. Incoming data are demodulated and decoded from the received amplitude shift keying (ASK) modulation signal and outgoing data are generated by load variation using bit phase shift keying (BPSK) coding of a 847 kHz sub-carrier. The SRIX4K chip is further described in the paper “A New Contactless Smartcard IC using an On-Chip Antenna and an Asynchronous Micro-controller” by Abrial A., at al., 26th European Solid-State Circuits Conference, Stockholm, Sep. 19, 20, 2000. 
   Using the STMicroelectronics single chip coupler, CRX14, design a reader may be readily designed to create a complete a RFID system. Although these and other such systems include electronic authentication mechanisms for enhanced security, it is nonetheless desirable to enhance the security of the information on the data card by affirmatively disabling the data card except when the holder intends to use it. 
     FIG. 1  illustrates a low-cost, user-operated, pressure responsive switch mechanism  100  on an RFID payment card  101  which disconnects the antenna  103  from the on-card integrated circuit  105  when the card is not in use. The switch mechanism  100 , seen in cross-section in  FIGS. 2 and 3 , is formed by a wire  121  connected to one end of the antenna  103  and held in a normally spaced-apart relationship from an electrical contact pad  123  by a two support cushions  131  and  132 . The cushions  131  and  132  are formed of a resilient material and are positioned on each side of the contact pad  123 . The wire  121  is secured by a thin adhesive strip  134  indicated by the dotted rectangle in FIG.  1 . 
   The switch assembly  100  is sandwiched between two planar panels  141  and  142  which form the outer surfaces of the card  101  and which also house the integrated circuit  105  and the antenna  103 . The panels  141  and  142  are attached at their periphery to form a sealed housing for the on-card electronics, switching mechanisms and antenna, and may be formed using any suitable non conducting material. The antenna  103  is formed with a helical conductive trace which follows the outer periphery of the card  101  and is available from RCD Technology Corporation, Bethlehem, Pa. The antenna could be made from any suitable conducting antenna design. 
   The switch assembly  100  is actuated to complete a circuit between the antenna  103  and the chip  105  when the user pressed inwardly on the flexible outer surface of the card as illustrated in FIG.  3 . The resilient cushions  131  and  132  deform, allowing the wire  121  to move into engagement with the contact pad  123  to establish and electrical connection. Note that, as shown in  FIG. 3 , the wire  121  is relatively rigid and moves downwardly in cantilever fashion with the resiliency being supplied primarily by the supporting cushions. Alternatively, the wire may be flexible and resilient and be supported at one or both ends. In this case, the wire acts as a spring, its resiliency preventing it from making contact until the surface of the data card is pressed, and when pressure is released, the wire pops back up, breaking the contact and terminating the electrical connection between the chip  103  and the antenna  105 . 
     FIG. 4  illustrates a second pressure responsive switch mechanism  400  on an RFID payment card  401  which disconnects the antenna  403  from the on-card integrated circuit  405  when the card is not in use. The switch mechanism  400 , seen in cross-section in  FIGS. 5 and 6 , includes a wire  421  connected to one end of the antenna  403  and held in a normally spaced-apart relationship from an electrical contact pad  423  by a two support cushions  431  and  432 . The cushions  431  and  432  are formed of a resilient material and are positioned on each side of the spring clip contact  123 . The wire  421  may be secured by a thin adhesive strip (not shown in  FIGS. 4-6 ) as shown at  134  in  FIGS. 1-3 . 
   The switch assembly  400  is sandwiched between two planar panels  441  and  442  which form the outer surfaces of the data card  401  and which also house the integrated circuit  405  and the antenna  403 . The panel  441  is molded to form a dome shaped dimple seen at  450  which is positioned over the switch assembly  400  and acts as a Belleville spring. When the user presses on the dimple  450  as shown in  FIG. 6 , the resilient dimple deflects inwardly, urging the wire  421  into engagement with the distal end  452  of the cantilevered arm of the spring clip  423 . The upper surface of the clip end  452  is oriented at an angle to the direction of motion of the wire  421 , creating a wiping action as the wire and clip engage, and providing self-cleaning of the metallic contacts to ensure a good electrical connection during the life of the card. 
   The cardholder can feel the presence of the dimple on the card, providing a tactile indication to the cardholder of the place on the card which should be pressed to activate the card. In addition, when the dome-shaped dimple is depressed, it deforms to allow the cardholder to feel a significant movement as the switch closes. The noticeable movement provides tactile feedback to the cardholder to confirm that the switch has been properly activated. 
   The chamber which enclosed by the dimple may be sealed as shown in  FIG. 5  at  460  and  461 , except for one or more bleed apertures as seen at  470  which permit a measured flow of air or fluid into and out of the chamber. When the dimple  450  is depressed, the air or fluid is expelled through the bleed aperture as shown at  480  in FIG.  6 . Then, when the cardholder releases the dimple  450 , the air or fluid is returned into the chamber through the aperture  470  at a timed rate, creating a time delay before the switch contacts again open as the resilient dimple returns to its normal shape. The time delay provides a prolonged time interval during which the card is enabled to permit the chip to be powered up and communicate with the remote reader. Note also that, by filling the chamber with a fluid, the switch contacts may be protected against corrosion. 
     FIG. 7  shows a further embodiment of the invention in which the chip  705  is connected to the antenna  703  through the series combination of two normally open, magnetically-operated reed switches  730  and  740  which are oriented perpendicular to one another. The card is activated by key  750  formed off non-permeable material which contains a pair of perpendicularly oriented permanent magnets  770  and  780 . The magnets  770  and  780  are also oriented perpendicular to one another and are spaced such that, when the key  750  (shown attached to a key ring  760 ) is placed in the proper position adjacent to the surface of the card  701 , the magnets close both reed switches to connect the chip and antenna. The cardholder may position the key  750  on the card in alignment with the guidelines graphically printed on the card surface as illustrated at  790 . 
   Each of the reed switches  730  and  740  consists of a pair of flexible reeds made of a magnetic material and sealed in a glass tube filled with inert gas. The reeds are overlapped but separated by a small gap. The contact area of each reed is plated with a noble metal, such as Rhodium or Ruthenium, to provide the switch with stable characteristics and long life. Application of a magnetic field, generated by the permanent magnets  770  and  780 , to the switches causes the reeds to be magnetized. Only a magnetic field strong enough to overcome the resistive force caused by elasticity of the reed will close the circuit, and once the magnetic field is removed, the reeds are separated again by the effect of elasticity of the reeds. By orienting the reed switches perpendicular to one another, they are less likely to be simultaneously closed by any magnetic field from a more distant source. Suitable ultra-miniature reed switches having an outside diameter of 0.075 inches are available from Aleph International, San Fernando, Calif. 91340. It should be noted that magnetically operated switches may be formed from components which are an integral part of the mechanical and electrical structures of the card, thereby reducing cost by eliminating the need to procure and assemble individual switching components, such as reed switches. 
   A still further embodiment of the invention shown in  FIG. 8  of the drawings employs capacitive coupling between a pattern of thin film conductors on the card  801  and a corresponding pattern of conductors on a key  850 . The pattern on the card includes three pairs of adjacent semicircles seen at  861 ,  862  and  863 . The key  850  is formed on non-conducting material and carries three conductive disks  871 ,  872  and  873 . When the key  850  is properly positioned flush against the surface of the card  801 , with the disks  871 ,  872  and  873  aligned with the patterns  861 ,  862  and  863  respectively, each disk on the key capacitively couples each pair of semicircular patterns on card, forming a pathway on the card for the radio frequency signal induced on the antenna  803 . Because of the high frequency of the signal (e.g. a 13.56 MHz carrier), the capacitive coupling added by the proximity of the matching key disks provides a low impedance path to complete the circuit. 
   To prevent the card from being activated when placed near other electrically conductive items, an additional pair of semicircular patterns seen at  881  and  882  are placed between the semicircular patterns  861 ,  862  and  863 . When conductive material is in the vicinity of either the semicircular pattern  881  or  882 , the resultant capacitive coupling produces a low impedance path across the antenna terminals, effectively “short circuiting” the antenna and disabling the connection. In this way, to enable the card, the cardholder may position the key  850  on the card in alignment with the guidelines graphically printed on the card surface as illustrated at  890 . If a matching key is not properly placed relative to the card, the card will not be enabled and cannot be surreptitiously read. 
   The switching mechanisms described above may be used to selectively connect the chip electronics to different portions of the on-card antenna, allowing the card to be selectively tuned to different resonant frequencies. The card may be pressed in different positions to activate different switching elements, and different keys, or different placements of a single key, may be used to selectively close only certain on-card switches to provide the needed connections. 
   It is to be understood that the methods and apparatus which have been described are merely illustrative applications of the principles of the invention. Numerous modifications may be made to the arrangements described without departing from the true spirit and scope of the invention.