Abstract:
An RFID tag that is foldable about a generally transverse fold line. The line divides the tag into two regions. One region has an RFID integrated circuit and areas of electrically conductive material. The other region has conductive areas that provide an efficient RFID antenna. In a folded configuration the areas are operatively associated with the integrated circuit while in the open configuration the areas are not functionally associated with the integrated circuit. Accordingly in the open configuration the tag is disabled or its RFID performance substantially degraded. The tag can be reversibly altered between the open and folded configurations.

Description:
BACKGROUND TO THE INVENTION 
       [0001]    Low-cost passive radio frequency identification (RFID) tags are expected to be used in the future to identify and track various items, including consumer products. A typical passive RFID tag includes a thin, flexible substrate to which is applied an RFID integrated circuit (or chip) and radio frequency (RF) antenna. The RF antenna is coupled to the RFID chip and enables communication between the RFID chip and a remote RFID reading device. The tags usually include an attachment means—typically a layer of pressure-sensitive adhesive—to attach the tag to an item. The RFID chip incorporates an electronic memory that typically stores a unique chip identification code and may also have additional storage capability for other data. 
         [0002]    RFID technology provides several key advantages over existing automated identification technologies (such as barcode technology), including:
       the ability to read an RFID tag from a distance without requiring line-of-sight access to the tag;   the ability to read multiple RFID tags at high speed;   (depending on the type of RFID chip) the ability to write information to an RFID tag.       
 
         [0006]    An issue that has arisen regarding the use of RFID tags on consumer goods is the privacy of the consumer. One concern is that it may be possible for an RFID tag on a tagged item to be read after the item has been purchased and without the consumer being aware that reading of the tag has occurred. This may violate the privacy rights of consumers by allowing their shopping habits, movements, or product usage habits to be monitored. 
         [0007]    One solution is to destroy or permanently disable the RFID tag after purchase of the tagged consumer item. While this would resolve the privacy concerns, it would have the disadvantage that if the consumer item is returned the store will no longer be able to use the RFID tag to identify it. 
         [0008]    Other solutions have been proposed, in which the RFID performance of the tag can be permanently degraded after the tagged item is purchased, such that the RFID tag can still be read but only from a very short distance, thereby practically speaking preventing any tracking of a tagged item after the tag has been so modified. While this type of solution would resolve the privacy concern, and would allow returned items to be identified by means of the RFID tag, it would have the disadvantage that returned items could not be further processed through a retailer&#39;s RFID system due to the limited read distance of the modified tag, and so the returned item would in all probability need to be retagged. 
         [0009]    A further disadvantage of using standard RFID tags to identify consumer products is that standard RFID tags do not incorporate any physical security features and so can easily be transferred from one item to another without their RFID function being affected. Consequently, after purchase of an item its RFID tag may be transferred to another item that is then brought back to the retailer as a product return. If the RFID tag is used to identify the returned item the store may issue a credit against the wrong item. 
       OBJECT OF THE INVENTION 
       [0010]    The object of the present invention is to overcome or substantially ameliorate the above disadvantages. 
       SUMMARY OF THE INVENTION 
       [0011]    There is disclosed herein an RFID tag including: 
         [0012]    a substrate; 
         [0013]    an RFID integrated circuit secured to said substrate; 
         [0014]    an RFID antenna also secured to said substrate; and wherein said tag is arrangeable in a first configuration in which said integrated circuit and said antenna are operatively electrically coupled to provide an RFID function, and a second configuration in which electric coupling of said antenna and circuit is altered to change said function, with said tag being alterable from said first configuration to said second configuration, and from said second configuration to said first configuration to at least partly reverse said change to said function. 
         [0015]    Preferably, said function is degraded or disabled when said tag is in said second configuration, relative to said function when said tag is in said first configuration. 
         [0016]    Preferably, when said antenna is operatively electrically coupled to said integrated circuit, conductive coupling is not included. 
         [0017]    Preferably, said antenna is operatively electrically coupled to said integrated circuit via capacitive coupling or inductive coupling. 
         [0018]    Preferably, said tag is a passive RFID tag. 
         [0019]    Preferably, said tag is an active or semi-active RFID tag. 
         [0020]    Preferably, said RFID tag includes a power source. 
         [0021]    Preferably, said substrate is folded back upon itself when said tag is rearranged from said second configuration to said first configuration, so as to change from an open configuration to a closed folded configuration. 
         [0022]    Preferably, said antenna is located adjacent to said integrated circuit in said first configuration, and displaced from said integrated circuit in said second configuration. 
         [0023]    Preferably, said tag includes an adhesive to releasably retain the tag in the first configuration. 
         [0024]    Preferably, said tag includes a tamper indicating feature that degrades said function when said tag is removed from an object to which it is attached. 
         [0025]    Preferably, coupling of said antenna and circuit is disrupted permanently when said tag is removed from an object to which it is attached. 
         [0026]    Preferably, said tag is rectangular with a longitudinal axis, with the tag being folded transverse of said axis between the first and second configurations. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0027]      FIG. 1  is a schematic illustration of an RFID tag with modifiable RFID performance; 
           [0028]      FIG. 2  is a schematic illustration of the RFID tag of  FIG. 1  in an opened configuration after application to a surface, such that its RFID performance is disabled or substantially degraded relative to the performance of the tag in a closed configuration; 
           [0029]      FIG. 3  is a schematic illustration of a second embodiment of an RFID tag with modifiable RFID performance; 
           [0030]      FIG. 4  is a schematic illustration of the RFID tag of  FIG. 3  in an opened configuration after application to a surface, such that its RFID performance is disabled or substantially degraded relative to the performance of the tag in a closed configuration; 
           [0031]      FIG. 5  is a schematic illustration of an RFID tag with both modifiable RFID performance and tamper-indication security, the tamper indication feature being such that the RFID function of the tag is irreversibly disabled or substantially degraded if the tag is removed from a surface to which it has been applied. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0032]    The present invention will now be described by way of non-limiting example with reference to the embodiments illustrated schematically in  FIGS. 1 to 5 . 
         [0033]      FIG. 1  is a schematic illustration of an RFID tag that is the subject of the present invention. 
         [0034]    The RFID tag  100  of  FIG. 1  is produced initially in the form of a flat rectangular tag having a longitudinal axis, as shown in  FIG. 1A . The flat tag of  FIG. 1A  is folded along a fold line  101  that is transverse of the longitudinal axis into the folded configuration of  FIG. 1B  that is applied to a surface  102 . 
         [0035]    The fold line  101  divides the RFID tag into two regions—region  1  and region  2  —as illustrated in  FIG. 1A . Regions  1  and  2  do not need to be the same size and shape. 
         [0036]    The preferred embodiment of  FIG. 1  is described and illustrated in relation to an RFID tag that incorporates a radio frequency (RF) antenna to enable communication with a remote RFID reading device. It should be appreciated that the antenna design shown in  FIG. 1  is illustrative only, and that various different designs of RFID tag antenna may be used while still embodying the invention described herein. 
         [0037]    At some radio frequencies RFID tags use so-called near-field effects to communicate with a reading device, and incorporate an induction coil antenna in the RFID tag instead of a more conventional RF antenna (such as, for example, a dipole antenna). As described in more detail below, it should be appreciated that the principles described herein apply equally to RFID tags that use an induction coil antenna. 
         [0038]    The unfolded RFID tag configuration illustrated in  FIG. 1A  comprises a tag substrate  103  to the upper surface of which an RFID integrated circuit, or chip,  104  is attached in region  1  of the tag. At least one area  105  of electrically conducting material is applied to the upper surface of region  1  of the substrate  103  such that the areas  105  of conducting material connect electrically to connection points on the RFID integrated circuit (IC)  104  and extend a distance onto the upper surface of region  1  of the substrate  103 . The conducting areas  105  are designed such that on their own they provide a poor antenna for the RFID integrated circuit  104 . The substrate is flexible along the fold line  101  to provide for folding. 
         [0039]    On the lower surface of region  1  of the substrate  103  an adhesive layer  106  is applied, as illustrated in  FIG. 1A . The adhesive layer  106  is preferably a strong or permanent adhesive that attaches the RFID tag  100  to a surface  102 . 
         [0040]    At least one area  107  of electrically conducting material is applied to the upper surface of region  2  of the substrate  103 . A layer of adhesive  108  is applied to the upper surface of the substrate  103  in region  2  over the areas  107  of conducting material. 
         [0041]    The open RFID tag  100  illustrated in  FIG. 1A  is folded along the fold line  101  to produce the working RFID tag  100  illustrated in  FIG. 1B . The tag substrate  103  may be perforated or modified in some way along the fold line  101  so as to promote folding along the fold line  101 . The folded RFID tag  100  is attached to a surface  102  by means of the adhesive layer  106 . 
         [0042]    After the tag  100  is folded into the configuration illustrated in  FIG. 1B  at least a portion of the conducting areas  107  is brought into close proximity with at least a portion of the electrically conducting areas  105 , resulting in the conducting areas  105  and  107  being electrically coupled to each other by means of a non-contact coupling method such as capacitive coupling or inductive coupling. The conducting areas  107  are configured such that when coupled to the conducting areas  105 , they provide an efficient RFID antenna for the RFD) integrated circuit  104 , and the RFID tag  100  thereby becomes functional when it is folded as illustrated in  FIG. 1B . The tag  100  may be supplied in this folded configuration. It should be appreciated that a non-contact coupling method is proposed for coupling conducting areas  105  to conducting areas  107 , so that actual physical contact of the areas  105  and  107  is not required. 
         [0043]    In the schematic illustration of  FIG. 1A  two separate conducting areas  105  and two separate conducting areas  107  are shown. When the tag  100  is folded as illustrated in  FIG. 1B  a portion of each of the conducting areas  107  is directly adjacent to a portion of one of the conducting areas  105 . If the conducting areas  105  and  107  are designed correctly, this will enable capacitive coupling between adjacent conducting areas  105  and  107 , thereby coupling the conductive areas  105  and  107  and forming an efficient RFID antenna for the RFID integrated circuit  104 . This type of design may be employed, for example, in the case of UHF RFID tags—such as the so-called EPC (Electronic Product Code) tags—operating at a frequency of around 900 MHz. 
         [0044]    The RFID function of the RFID tag  100  can be deliberately disabled, or at least substantially degraded, by simply lifting region  2  of the folded RFID tag  100  away from region  1 , as illustrated in  FIG. 2 . When the tag is partly unfolded in this way, the conducting areas  107  are removed a distance from the conducting areas  105  and the efficiency of the electrical coupling between conducting areas  105  and  107  is thereby reduced. The RFID integrated circuit  104  therefore is no longer coupled to an efficient RF antenna within the RFID tag  100 , and the RFID function of the tag  100  is disabled or substantially degraded. Generally speaking, the efficiency of non-contact coupling methods diminishes rapidly as the distance between the coupled electrically conducting areas increases, so the RFID tag  100  does not need to be opened far before its RFID function is substantially diminished. 
         [0045]    Folding region  2  of the RFID tag  100  back down onto region  1  restores the RFID function of the tag by again bringing conducting areas  105  and  107  into close proximity. 
         [0046]    Preferably the adhesive layer  108  is re-attachable, so that region  2  of the RFID tag  100  can be folded and attached to region  1  of the RFID tag  100  a number of times—in other words, the RFID tag  100  can be folded and unfolded a number of times. 
         [0047]      FIG. 3  illustrates an RFID tag  300  that is a variation on the preferred embodiment illustrated in  FIG. 1 . In the embodiment of  FIG. 3  the adhesive layer  108  of  FIG. 1  is absent and instead an adhesive layer  301  is applied uniformly to the upper surface of region  1  of the substrate  103  over the RFID integrated circuit  104  and conducting areas  105 . As illustrated in  FIG. 3B , region  2  of the substrate  103  is folded over and applied to the top of the adhesive layer  301  in order to couple the conducting areas  105  to the conducting areas  107  and thereby enable the RFID function of the RFID tag  300 . The folded RFID tag  300  illustrated in  FIG. 3B  is similar to the folded RFID tag  100  illustrated in  FIG. 1B . As in the case of the RFID tag embodiment illustrated in  FIGS. 1 and 2 , the RFID function of the folded RFID tag  300  can be deliberately disabled or substantially degraded by lifting region  2  of the substrate  103  away from region  1  (i.e. by lifting region  2  of substrate  103  away from the adhesive layer  301 ), as illustrated in  FIG. 4 . As in the embodiment of  FIGS. 1 and 2 , preferably the adhesive layer  301  is a re-attachable adhesive, so that region  2  of the substrate  103  can be lifted away from and reapplied to the adhesive layer  301  a number of times. 
         [0048]    It should be appreciated that numerous variations are possible on the embodiments described in relation to  FIGS. 1 to 4 . Non-limiting examples of such variations are provided below. 
         [0049]    RFID tag antenna designs (including induction coil RFID antenna designs) different from those described in relation to  FIGS. 1 to 4  may be employed. 
         [0050]    Different methods may be used to attach region  2  of the RFID tag  100  or  300  to region  1  of the RFID tag  100  or  300  to enable the RFID function of the tag. 
         [0051]    Region  2  of the RFID tag  100  or  300  may have a form factor (size and shape) that is different from region  1  of the RFID tag  100  or  300  —it is not necessary for region  2  to match region  1 . 
         [0052]    As described above, the preferred embodiments illustrated in  FIGS. 1 to 4  use a so-called far-field RF antenna in the tag. Some RFID tags—for example, tags that operate in the so-called low frequency (around 100 kHz) and high frequency (around 13 MHz) bands—instead use near-field techniques to enable communication between the RFID tag and a reader. In this case the RFID tag may use an induction coil antenna to enable communication between the RFID tag and a reader. It should be appreciated that the principles described herein apply equally to RFID tags that use an induction coil antenna and to RFID tags that use any of the far-field antenna designs (such as, for example, a dipole antenna). In the case of an induction coil antenna the conductive areas  105  may be configured to form a single induction coil connected via two connection points to the RFID integrated circuit  104 . The conductive areas  107  may then be configured to form a second induction coil that couples inductively to the induction coil formed by the areas  105  when the RFID tag  100  or  300  is folded closed as illustrated in  FIGS. 1B and 3B . The induction coil  107  thereby couples to the RFID integrated circuit  104  via the induction coil  105 , and is configured to enable communication to a remote RFID reading device. Since the communication range using an induction coil antenna is dependant (among other factors) on the area of the coil, the induction coil  105  would preferably be small and allow coupling to the induction coil  107  over only a very short distance, and would not enable communications to a remote RFID reading device. On the other hand the induction coil  107  would preferably be larger in overall area so as to enable communication with a remote RFID reading device. As described in relation to the embodiments of  FIGS. 1 to 4 ; when region  2  of the RFID tag  100  or  300  is folded over and brought into close proximity to region  1  of the RFID tag  100  or  300 , induction coil  105  will couple inductively to induction coil  107 , thereby coupling the RFID integrated circuit  104  to an efficient RFID antenna and enabling the RFID function of the tag  100  or  300 . Similarly, when region  2  of the RFID tag  100  or  300  is lifted away from region  1  of the RFID tag  100  or  300  the induction coil  105  no longer couples efficiently to induction coil  107  and the RFID function of the tag  100  is either disabled completely or substantially degraded. 
         [0053]    In another variation on the embodiments of  FIGS. 1 to 4  the RFID tag may include a tamper indicating feature such that the RFID function of the tag is disabled in a non-reversible manner if the tag is removed from a surface  102  to which it has been applied. Such a tamper indicating feature is useful in ensuring that the RFID tag cannot be moved from one item to another without its RFID function being disabled or degraded in a way that is not readily reversible. 
         [0054]    One preferred embodiment for providing the above described tamper indicating capability will now be described by way of a variation on the RFID tag  100  of  FIGS. 1 and 2 . This tamper indicating technique for RFID tags is described in detail in U.S. Pat. No. 6,888,509, but has not previously been presented in combination with the modifiable RFID tag performance invention described herein. Modifiable RFID tag performance (as described in relation to the embodiments of  FIGS. 1 to 4 ) and RFID tamper indication are complementary features that when used together each enhance the value of the other to an end user. It should be appreciated that the tamper indicating capability described below can be applied to the RFID tag embodiment of  FIGS. 3 and 4  or other RFID tag embodiments described herein, or to other RFID tag embodiments that incorporate the modifiable RFID tag performance capability described herein. 
         [0055]      FIG. 5  is an illustration of an RFID tag  500  that is a variation on the RFID tag embodiment of  FIGS. 1 and 2 . The RFID tag  500  is similar to the RFID tag  100  except that in the case of the RFID tag  500  the RFID integrated circuit  104  and electrically conducting areas  105  are applied to the lower surface of region  1  of the substrate  103  and covered by the adhesive layer  106 . When the RFID tag  500  is in its folded configuration and is therefore functional, as illustrated in  FIG. 5B , the conducting areas  105  couple to the conducting areas  107  through both the adhesive layer  108  and the substrate material  103 . In the embodiment of  FIG. 5  the objective is to ensure that if the tag  500  is removed from a surface  102  to which it has been applied, at least either the conductive areas  105  or connection between the conductive areas  105  and the integrated circuit  104  will be disrupted so as to disable or substantially degrade the coupling between conducting areas  105  and  107  or between the integrated circuit  104  and the conductive areas  107 , thereby disabling or substantially degrading the RFID function of the RFID tag  500 . 
         [0056]    In one preferred embodiment of the RFID tag  500  the conducting areas  105  are formed using a destructible electrically conductive material, such as conductive ink. Other destructible electrically conducting materials may be used instead. To promote damage or disruption to the conductive areas  105  if the tag  500  is removed from the surface  102 , one or more adhesion modifying layers  501  may be applied between the substrate  103  and the adhesive layer  106  at least in the vicinity of the conducting areas  105  so as to modify the relative adhesion of the substrate  103 , the conductive areas  105 , and the adhesive layer  106  in order to result in damage or disruption to the conducting areas  105  on removal of the tag  500  from the surface  102 . In  FIG. 5  the adhesion modifying layers  501  (there may be one or more such layers) are shown between the substrate  103  and the conductive areas  105 , but it should be appreciated that the adhesion modifying layers  501  may instead or also be applied between the conductive areas  105  and the adhesive layer  106 . The adhesion modifying layers  501  may be applied in a specified pattern (as viewed from below the substrate  103 ) so as to create a plurality of areas of differing relative adhesion strengths and thereby promote disruption or damage to the conductive areas  105  if the tag  500  is removed from the surface  102 . Where present, the adhesion modifying layer  501  modifies adhesion of the layers that it separates. The adhesion modifying layer  501  may either enhance or reduce the adhesion of two layers that it separates. Preferably, but not necessarily, the adhesion modifying layer  501  will reduce the adhesion of two layers that it separates. In the preferred embodiment illustrated in  FIG. 5  an adhesion modifying layer  501  is applied in a specified pattern between the substrate  103  and conductive areas  105 , reducing adhesion of the electrically conductive areas  105  to the substrate  103  in those areas where the adhesion modifying layer  501  is applied, and in those areas thereby promoting separation of the conductive areas  105  from the substrate  103  if the tag  500  is removed from the surface  102 . Removing all or part of the conductive areas  105  from the lower surface of the substrate  103  would disable or substantially degrade coupling between the conducting areas  105  and conducting areas  107 , thereby disabling or substantially degrading the RFID performance of the RFID tag  500 . In a variation on this embodiment, the adhesion modifying layer  501  may comprise a treatment on the lower surface of the substrate  103 , applied either uniformly or in a specified pattern, such that in the treated areas the adhesion to the substrate  103  of an adjacent layer is modified, either by being increased or by being decreased, relative to the adhesion of the adjacent layer to the substrate  103  in areas where the surface treatment has not been undertaken. In another variation on the embodiment of  FIG. 5 , the adhesion modifying layer  501  may be applied between the substrate  103  and RFID integrated circuit  104  in addition to being applied between the substrate  103  and conducting areas  105 , such that if the RFID tag  500  is removed from the surface  102  the RFID integrated circuit  104  will be removed from the substrate  103  in addition to the conducting areas  105  being separated from the substrate  103  in those areas where the adhesion modifying layer  501  is applied. In another variation on the embodiment of  FIG. 5  the RFID integrated circuit  104  may be applied to the upper surface of the substrate  103  and either directly connected or coupled to the conducting areas  105  on the lower surface of the substrate  103 , with the conducting areas  105  being coupled to the conducting areas  107  when the RFID tag  500  is in the folded configuration shown in  FIG. 5B , thereby enabling the RFID function of the RFID tag  500 , as described above. 
         [0057]    It should be appreciated that the tamper indicating capability described in relation to the RFID tag  500  of  FIG. 5  can also be applied to other RFID tag designs with modifiable RFID performance, including the RFID tag design illustrated in  FIGS. 3 and 4  and other RFID tag designs described herein. 
         [0058]    In alternative forms the RFID tags  100 ,  300  or  500  are active or semi-active RFID tags having an on-board power source such as a battery. 
         [0059]    In the embodiment of  FIGS. 1 to 5 , the integrated circuit  104  and conductive areas  105  are in region  1  and the conductive areas  107  are in region  2 , with region  1  being affixed to a surface  102  in order to apply RFID tag  100 ,  300  or  500  to an object. In a variation on all of the embodiments of  FIGS. 1 to 5 , the conductive areas  107  are instead in region  1 , with the integrated circuit  104  and conductive areas  105  in region  2 . In this variation on the preferred embodiment of  FIG. 5 , the conductive areas  107  are on the bottom surface of the substrate  103  along with the adhesion modifying layers  501 , as described in relation to  FIG. 5 .