Patent Publication Number: US-2022230043-A1

Title: Rfid device and method of manufacturing the same

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to radio frequency identification (RFID) devices, in particular, to an RFID device configured to be attached to a piece of material, for example, a piece of fabric, and a method of manufacturing the same. 
     BACKGROUND 
     Generally, RFID devices such as, for example, RFID cards, RFID tags, etc. include an RFID antenna and an integrated circuit connected to the RFID antenna. Upon presence of an electromagnetic field emitted by a reader device, the RFID antenna supplies energy from the electromagnetic field to the integrated circuit, which integrated circuit may communicate with the reader device using radio frequency (RF) communication protocols. In this manner, for example, data can be read from a memory associated with the integrated circuit, and can also be written into said memory, if desired. 
     US 2019/0012587 A1 discloses an RFID transponder including a plastic package which accommodates transponder components such as a chip and an antenna as integrated components. 
     The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems. 
     SUMMARY OF THE DISCLOSURE 
     According to one aspect of the present disclosure, an RFID device comprises a substrate, an integrated circuit mounted on the substrate, and a wire antenna coupled to the integrated circuit to allow the integrated circuit to perform RFID communications via the wire antenna. The substrate includes an attachment portion for attaching the wire antenna to the substrate. Further, the wire antenna includes a connecting portion configured to connect the wire antenna to a piece of material, in particular, a piece of fabric, in a state of being attached to the substrate. Accordingly, the substrate is configured to be connected to the piece of material via the wire antenna. 
     According to another aspect of the present disclosure, a method of manufacturing an RFID device comprises providing a substrate having an integrated circuit mounted on the same, attaching a wire antenna to the substrate, the wire antenna being coupled to the integrated circuit to allow the integrated circuit to perform RFID communications via the wire antenna, and connecting the wire antenna to a piece of material, in particular, a piece of fabric, in a state of being attached to the substrate, to thereby connect the substrate to the piece of material via the wire antenna. 
     According to a further aspect, a product, for example, a piece of clothing, comprises the RFID device of the above aspect connected to the product via the wire antenna. 
     Other features and aspects of the present disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of an RFID device provided on a piece of fabric; 
         FIG. 2  is a plan view of the RFID device connected to the piece of fabric; 
         FIG. 3  is a detailed view of a substrate of the RFID device in  FIG. 2 ; and 
         FIG. 4  is a bottom view of a substrate of an exemplary RFID device in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described herein are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered as, a limiting description of the scope of protection. Rather, the scope of protection shall be defined by the appended claims. 
     The present disclosure is based at least in part on the realization that commonly used RFID devices for, for example, pieces of clothing, may have a size that makes it difficult for the RFID device to be connected to the piece of clothing in such a manner that it is invisible or mostly invisible. In addition, the RFID device may be rigid and create a feeling of discomfort when being worn. In addition, the RFID device can easily be detected. Further, attachment of the RFID device to the piece of clothing may be difficult and require several steps including, for example, sewing, patching or inserting the RFID device into a pouch formed in the piece of clothing. Accordingly, it is desirable to reduce the size of the RFID device, increase the flexibility of the same, make it harder to detect the same, and also simplify the process for attaching the same to the piece of fabric. 
     In addition, the present disclosure is based at least in part on the realization that it may be desirable to provide the RFID device such that it has a form factor which allows for embedding the RFID device into a piece of material, for example, a hem of a piece of clothing or the like. 
     The present disclosure is based on the realization that the size of the RFID device can be substantially reduced when any packaging or housing for accommodating an integrated circuit and an antenna of the RFID device are removed/omitted. Instead, it has been realized that it is advantageous to connect the RFID device to the piece of material via the wire antenna. In particular, it has been realized that the wire antenna can be attached to a substrate of the RFID device, and can then be connected to the piece of material to thereby also connect the substrate of the RFID device to the piece of material. In particular, it has been realized that it may be advantageous to provide an attachment portion in the form of one or more through holes in the substrate for passing the wire antenna through said through holes prior to connecting the same to the piece of material. Thereby, the substrate is held on the piece of material by the wire antenna. 
     The present disclosure is also based on the realization that a coating of the wire antenna can be used in an advantageous manner to connect the same, for example, to the piece of material. For example, such a coating can be formed from a material having a thermoset capability, which allows connecting the wire antenna to the piece of material simply by heating the wire antenna with the coating, similar to a known patching process. 
     Referring now to the drawings,  FIG. 1  shows a plan view of an RFID device  10  in accordance with the present disclosure. As shown in  FIG. 1 , RFID device  10  comprises a substrate  12  and a wire antenna  16  configured to be connected to a piece of fabric  22 . In the exemplary embodiment, the piece of fabric is a piece of clothing having a hem  23 . For the sake of illustration, RFID device  10  is shown in  FIG. 1  as being arranged on top of hem  23 . In practice, however, RFID device is embedded in hem  23  after being attached. As shown in  FIG. 1 , wire antenna  16  extends from substrate  12  on opposite sides of the same in a substantially linear manner. In particular, RFID device  10  is configured to be arranged on piece of fabric  22  in such a manner that it extends substantially parallel to hem  23 , such that RFID device  10  can be embedded into hem  23  in a known manner after having been connected to piece of fabric  22 . Such techniques for embedding are well-known and will therefore not be described herein. 
     As shown in more detail in  FIGS. 2 and 3 , RFID device  10  comprises an integrated circuit  14  mounted on substrate  12  in a known manner. Further, wire antenna  16  is coupled to integrated circuit  14  to allow integrated circuit  14  to perform RFID communications via wire antenna  16 . For example, integrated circuit  14  may be configured to be inductively coupled to wire antenna  16 , via a coupling loop  15  provided on substrate  14  and electrically connected to integrated circuit  14  in a known manner. Further, as shown in  FIG. 3 , wire antenna  16  is attached to substrate  12  via an attachment portion  18  of substrate  12 . In the exemplary embodiment, attachment portion  18  includes a pair of through holes  24  formed in substrate  12 , and wire antenna  16  is passed through the pair of through holes  24  to extend from opposite sides of substrate  12 , as shown in  FIG. 2 . In the exemplary embodiment, the pair of through holes  24  is formed on opposite sides of substrate  12 , at a position adjacent to two corner portions of substrate  12  provided on one side of substrate  12 . Of course, it will be appreciated that the pair of through holes can be provided at any appropriate position of substrate  12 , at least as long as it can be assured that a coupling portion  26  (see  FIG. 4 ) of wire antenna  16  that extends across the substrate between the pair of through holes  24  can be inductively coupled to integrated circuit  14 . 
     As shown in  FIG. 2 , wire antenna  16  includes a connecting portion  20  configured to be connected to the piece of fabric  22  in a state of being attached to substrate  12 . In particular, connecting portion  20  may include a coating  28  of wire antenna  16 . Coating  28  is provided in at least one portion of wire antenna  16  and is configured to be fixedly connected to the piece of fabric  22 . In the exemplary embodiment shown in  FIG. 2 , coating  28  is provided over the entire length of wire antenna  16 . This has the advantage that wire antenna  16  can be easily attached to substrate  14 , without having to make sure that a coated portion of the same has a specific positional relationship with respect to substrate  12  and/or piece of fabric  22 . However, in other embodiments, only part of wire antenna  16  may be covered by coating  28 . 
     In the present example, coating  28  may include a thermoset adhesive material, for example, a thermoset PU material, and wire antenna  16  may be configured to be connected to piece of fabric  22  via heating of the portion of coating  28  including the coating with the thermoset adhesive material. This is shown in  FIG. 2 , where portions of wire antenna  16  adjacent to substrate  12  are shown in a state of being connected to piece of fabric  22  after having been heated in an appropriate manner. Attachment of thermoset adhesive materials to, in particular, pieces of fabric, for example, in a known patching process, are well-known, such that the description will be omitted. It is evident from  FIG. 2  that, with the portions of wire antenna  16  adjacent to substrate  12  being connected to (fused with) piece of fabric  22 , due to the fact that wire antenna  16  is attached to substrate  12  via through holes  24  (see  FIG. 3 ), substrate  12  is also connected to piece of fabric  22  via wire antenna  16  in this manner. Therefore, substrate  12  does not need to have a further connecting portion for connecting substrate  12  to RFID device  10 . This greatly simplifies the connection of RFID device  10  to piece of fabric  22 . 
     As shown in  FIG. 4 , in the example described above, attachment portion  18  includes the pair of through holes  24  formed in substrate  12 , and wire antenna  16  is attached to substrate  12  by being passed through the pair of through holes  24  from a first side S 1  of substrate  12  (in  FIG. 4 , S 1  corresponds to the bottom side of substrate  12 ). Further, as previously mentioned, wire antenna  16  includes coupling portion  26  extending across substrate  12  between the pair of through holes  24 . In some embodiments, substrate  12  may include a guide portion  13 , for example, one or more ribs or the like, configured to guide coupling portion  26  on substrate  12 . In this manner, it can be assured that coupling portion  26  has a desired positional relationship with respect to integrated circuit  14 , more particularly, coupling loop  15 . It should be mentioned that piece of fabric  22  is omitted from  FIG. 4  for the sake of illustration. In this manner, wire antenna  16  can be reliably coupled to integrated circuit  14 . It will be appreciated that the single coupling loop  15  shown in  FIG. 4  is only exemplary, and coupling loop  15  may include a plurality of loops, for example, two or three loops. 
     While in the example shown in  FIG. 3  coupling portion  26  extends substantially straight between the pair of through holes  24 , it will be appreciated that, in other embodiments, coupling portion  26  may at least partly surround integrated circuit  14 . For example, an appropriate guide portion  13  may be provided to guide coupling portion  26  accordingly, for example, to extend between through holes  24  as three sides of a rectangular shape, as shown in  FIG. 4 . 
     In some embodiments, guide portion  13  may be provided to cover at least part of coupling portion  26  provided on the substrate  12 . For example, guide portion  13  as shown in  FIG. 4  may include a one or more additional ribs and a top portion (not shown) provided over coupling portion  26  and connecting the ribs of guide portion  13 . In this case, wire antenna  16  can be inserted through a passage formed in guide portion  13 . 
     The coating may be formed from, for example, PU or a similar material, and may be configured to connect wire antenna  16  to piece of fabric  22  by being heated to a temperature in a range between 190° C. and 220° C. 
     In the above example, wire antenna  16  is configured as a linear dipole antenna. However, it will be readily appreciated that wire antenna  16  may have any appropriate configuration that allows for RFID communications between RFID device  10  and an external reader device. For example, a support layer (not shown) may be provided, on which wire antenna  16  having a desired arrangement (for example, one or more meanders) is arranged prior to being connected to piece of fabric  22 , and the support layer may be removed during or after connection of wire antenna  16  to piece of fabric  22 . 
     Although in the example described above connecting portion  20  includes a pair of through holes  24 , it will be appreciated that, in other embodiments, only a single through hole or several pairs of through holes  24  may be provided. Also in this case, wire antenna  16  may be inserted through through hole  24 , and mounting portions  20  of wire antenna  16  may then be connected to piece of fabric  22 , for example, by heating in the above-described manner. 
     In addition, although in the above-described example wire antenna  16  is attached to substrate  12  by being inserted through through holes  24 , in other embodiments, wire antenna  16  may be attached to substrate  12  in a different manner, for example, by welding or the like. In this case, integrated circuit  14  may also be electrically connected to wire antenna  16 . In other embodiments, wire antenna  16  and substrate  12  may be integrally provided, for example, on a support layer similar to the one mentioned above. However, also in this case, substrate  12  can be connected to piece of fabric  22  via wire antenna  16 , for example, by the above-described connection of mounting portion  20  by heating coating  28  of wire antenna  16  in a state in which the same is attached to substrate  12 . In some embodiments, an appropriate engagement portion can be provided on substrate  12 , for example, a clamping portion or the like for engaging a portion of wire antenna  16 . 
     Further, although mounting portion  20  has been described above as a coating  28  that fixedly connects wire antenna  16  to piece of fabric  22 , in other embodiments, different mounting portions including, for example, clamping portions, Velcro strips, pins etc. can be provided for wire antenna  16  to fixedly or detachably connect wire antenna  16  to piece of fabric  16 . In other embodiments, wire antenna  16  may be connected to piece of fabric  22  by ultrasonic (US) welding or the like, or may be stitched to piece of fabric  22 . 
     INDUSTRIAL APPLICABILITY 
     As described above, with the RFID device according to the present disclosure, a RFID device having a small size, in particular, a form factor that allows for arranging the same, for example, inside a hem of a piece of cloth, and being flexible and difficult to detect can be provided. An exemplary width of RFID device in the transverse direction (perpendicular to the direction of extension of wire antenna  16  and in a plane that includes substrate  12 ) may be between 2 and 10 mm. A length of RFID device  10  including wire antenna  16  may be between 5 and 20 cm (for example, around 15 cm for a linear wire antenna, and around 5 to 10 cm (or less) in case of an arrangement of the wire antenna with one or more meanders or the like), and a thickness may be between 0.1 and 2 mm. 
     Further, the RFID device can be easily attached to the piece of material by connecting a mounting portion of the wire antenna to the piece of material, for example, by heating the same. Due to this heating, a fixed connection via a thermoset adhesive material can be obtained between wire antenna  16  and, for example, piece of fabric  22 . As wire antenna  16  is attached to substrate  12  of RFID device  10 , in this manner, substrate  12  can also be easily connected to piece of fabric  22 . Accordingly, any bulky packaging or housing can be omitted. Further, RFID device  10  is very flexible, and can be easily hidden, for example, in a hem of a piece of clothing. 
     RFID device  10  is very easy to manufacture, and is also easy to connect to, for example, a piece of fabric  22 . An exemplary process for manufacturing the RFID device  10  will be described below. 
     In a first step, substrate  12  having integrated circuit  14  mounted on the same is provided. Then, wire antenna  16  is attached to substrate  12  in such a manner as to be coupled to integrated circuit  14  to allow integrated circuit  14  to perform RFID communications via wire antenna  16 . Finally, wire antenna  16  is connected to, for example, piece of fabric  22  in a state of being attached to substrate  12 , to thereby connect substrate  12  to piece of fabric  22  via wire antenna  16 . 
     In particular, the step of attaching wire antenna  16  may include passing wire antenna  16  through at least one, preferably at least two, through holes  24  formed in substrate  12 , for example, from a first side S 1  of substrate  12 . Of course, it will be appreciated that wire antenna  16  can be laced to substrate  12  in any appropriate manner, for example, by being inserted from one side of the same, passed over a portion of substrate  12 , and then being inserted through second through hole  24  formed on the opposite side. 
     The step of connecting wire antenna  16  may include heating at least one portion of wire antenna  16  in contact with piece of fabric  22 . For example, the at least one portion of wire antenna  16  may be provided with coating  28  including a thermoset adhesive material, for example, a thermoset PU material. The step of heating may be performed in a temperature range between 190° C. and 220° C. Due to the small size, less energy is needed to connect wire antenna  16 , and the time needed for the connection can also be shortened considerably. 
     While the above examples have been described in the context of attaching RFID device  10  to a piece of clothing, it will be readily appreciated that the above-described device and method can also be used in combination with other types of material, and in other applications, for example, fabrics such as cotton, polyester, wool, etc., and other materials which allow for the connection of wire antenna  16  by heating coating  28  of the same, for example, rubber materials used for tires, other plastics and the like. 
     It will be appreciated that the foregoing description provides examples of the disclosed systems and methods. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the general disclosure. 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method for referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All method steps described herein can be performed in any suitable order, unless otherwise indicated or clearly contradicted by the context. 
     Although the preferred embodiments of the present disclosure have been described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.