Abstract:
An RFID antenna for a POS device has a slender, single-sided, flexible substrate with a first end and a second end. Multiple conductors extend along the substrate, from the first end to the second end. A flexible covering layer is attached to the substrate and covers the conductors. The substrate is wrapped to superimposed the ends of the substrate. A connector connects the ends of the conductors on the first end of the substrate to the ends of the conductors on the second end of the substrate whereby the plurality of conductors form an antenna in the form of a continuous helical coil.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional patent application claims priority under 35 U.S.C. § 119(a) from Patent Application No. 201410857331.7 filed in The People&#39;s Republic of China on Dec. 30, 2014, the entire contents of which are hereby incorporated by reference. 
       FIELD OF THE INVENTION 
       [0002]    This invention relates to a Point of Sale (POS) device and in particular, to a radio frequency identification device (RFID) for a POS device. 
       BACKGROUND OF THE INVENTION 
       [0003]    With the development of communication industries, RFID technology has been widely applied in more and more fields. Radio frequency identification technology is a wireless communication technology with which a specific object may be identified and related data may be read and written based on a radio signal, without establishing a mechanical contact or an optical contact between an identification system and the specific object. 
         [0004]    The RFID technology is applied in many industries. For example, a tag is attached onto a car being produced, and the factory party may track the progress of the car on the production line. The position of a drug may be tracked in a warehouse. A radio frequency tag may be attached to livestock and pets, allowing the livestock and pets to be positively identified (“positively identified” means to avoid that several animals use the same identify). An identification card based on RFID technology may allow an employee to enter a locked building, and a radio frequency transponder in a car may be used for paying fees related to toll road and parking, for example. 
         [0005]    For portable electronic devices, such as a POS device, sometimes it is necessary to cover a safety protection device with resin or package the safety protection device, which results in the structure of the safety protection device being heavier and thicker. Therefore, an RFID antenna is widely used in the field of POS devices, to increase an internal space to accommodate more components, thereby making the POS device smaller and lighter. 
         [0006]      FIG. 1  shows a manufacturing process of an RFID antenna using conventional technology. The base material  1  is a flexible base material of 250 mm×320 mm, from which eight RFID antenna substrates  2  are cut. A helical coil of a conductor forming a layer on the antenna substrate  2  is formed by means of printing or etching to form a helical antenna. The conductors may be copper traces or other conductive traces. Ends of the conductor occur at an inner periphery and at an outer periphery. Since the end at the inner periphery of the antenna needs to be led to the outer periphery so that the two ends are connected together to other ports, through holes are arranged on the substrate to connect conductively the inner periphery to the outer periphery. Hence, the flexible base material must be a double-sided base material, that is, conductive lines may be arranged on both sides of the base material, which increases the cost and complicates the production process. In addition, this manner of making the antenna is not an efficient use of the material due to the high percentage of discarded material. This further increases the cost of the POS device. 
       SUMMARY OF THE INVENTION 
       [0007]    Hence, there is a desire for an antenna having a higher utilization of materials. 
         [0008]    Accordingly, in one aspect thereof, the present invention provides a flexible RFID antenna, comprising: a single-sided flexible substrate having a first end and a second end; a plurality of conductors arranged on the substrate, wherein the plurality of conductors are insulated from each other and extend between the first end and the second end of the substrate; and a flexible covering layer attached to the substrate with the conductors sandwiched between the substrate and the covering layer, wherein ends of the conductors at the first end of the substrate are electrically connected to ends of the conductors at the second end of the substrate, respectively, to form a helical RFID coil. 
         [0009]    Preferably, the substrate and the covering layer are of an elongated slender shape. 
         [0010]    Preferably, the substrate comprises a first insulating layer which is a polyester (PET) film or a polyimide (PI) film, with a thickness between 12 μm and 125 μm. 
         [0011]    Preferably, the substrate further comprises a first adhesive layer which attaches the plurality of conductors onto the substrate. 
         [0012]    Preferably, the covering layer comprises a second insulating layer which is a polyester (PET) film, a polyimide (PI) film or an insulating ink layer, with a thickness between 12 μm and 50 μm. 
         [0013]    Preferably, the covering layer further comprises a second adhesive layer which attaches the second insulating layer onto the substrate. 
         [0014]    Preferably, the covering layer comprises an insulating ink layer. 
         [0015]    Preferably, the substrate of the antenna is provided with a plurality of fixing parts for fixing the antenna. 
         [0016]    According to a second aspect, the present invention provides a POS device, comprising: a main body; a circuit board on the main body; and an RFID antenna disposed around the main body, wherein the RFID antenna comprises: a single-sided flexible substrate comprising a first end and a second end; a plurality of conductors arranged on the substrate, wherein the plurality of conductors are insulated from each other and extend from the first end to the second end of the substrate; a flexible covering layer attached to the substrate and covering the conductors; and a connector arranged on the main body, the connector being connected to ends of the conductors on the first end of the substrate and ends of the conductors on the second end of the substrate, such that the plurality of conductors form a helical coil, and the antenna is connected to the circuit board by the connector. 
         [0017]    Preferably, the substrate and the covering layer are slender in shape. 
         [0018]    Preferably, the antenna is provided with at least one fixing part for fixing the antenna to the main body at locations away from the first end and the second end. 
         [0019]    Preferably, the antenna is attached to the main body by adhesive. 
         [0020]    According to a third aspect, the present invention provides an electronic apparatus comprising a main body, a circuit board and a printed antenna, wherein the printed antenna comprises: a single-sided flexible substrate comprising a first end and a second end; a plurality of parallel conductors arranged on the substrate, wherein the plurality of parallel conductors extend from the first end to the second end of the substrate; a flexible covering layer attached to the substrate, the conductors being sandwiched between the substrate and the covering layer; and a connector arranged on the main body, wherein the connector connects ends of the conductors on the first end of the substrate to ends of the conductors on the second end of the substrate, whereby the conductors form a helical coil, and the antenna is connected to the circuit board via the connector, and the antenna is disposed around the main body. 
         [0021]    Using such an antenna, production efficiency is high, and as a circuit is needed to be printed on only one side of the antenna substrate, the production process is simplified and the cost is significantly reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    A preferred embodiment of the invention will now be described, by way of example only, with reference to figures of the accompanying drawings. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same reference numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below. 
           [0023]      FIG. 1  illustrates a prior art RFID antenna base material; 
           [0024]      FIG. 2  illustrates an RFID antenna base material according to one embodiment of the present invention; 
           [0025]      FIG. 3  is a view from above of one of the antennas shown in  FIG. 2 ; 
           [0026]      FIG. 4  is a schematic cross-sectional view along A-A of the antenna of  FIG. 3 ; 
           [0027]      FIGS. 5 a , 5 b  and 5 c    are schematic diagrams of connection of an RFID antenna according to one embodiment of the present invention, wherein the covering layer of the antenna body has been omitted; 
           [0028]      FIG. 6  is a perspective view of a connector for the RFID antenna of  FIG. 5 ; 
           [0029]      FIG. 7  is a sectional view, on an enlarged scale, of a part of the connector of  FIG. 6 , connected to the antenna; and 
           [0030]      FIG. 8  is a schematic structural view of a POS device using an RFID antenna according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]      FIG. 2  illustrates an exemplary structure of an RFID antenna base material according to the preferred embodiment of the present invention. In this embodiment, the entire base material  10  is a rectangular, single-sided, flexible base material, that is, a circuit may be printed or etched on only one side of the base material  10 . The antennas  20  are designed to be of a slender shape, such as an essentially elongated rectangular shape, and are arranged in sequence on the surface of the base material  10  on which a circuit may be printed or etched. Individual antennas  20  are cut from the base material  10 . Multiple parallel conductors  224  are arranged on each of the antennas  20  by means of printing or etching (see  FIG. 5 ). Through such process, 44 antennas may be formed on a base material  10  of 609 mm×320 mm, compared with only  8  antennas using the prior art method. Thus, the production efficiency is greatly improved by better material utilization. 
         [0032]    Conductor traces  224  are typically made of a copper material, but may be made of aluminum, silver, carbon, a mixture of silver and carbon, a transparent conductive polymer, or other conductive ink. Each of the above materials has specific characteristics suitable for the operation and function of the RFID antenna. The material of the conductor traces  224  is selected depending on the function of the RFID antenna. 
         [0033]      FIG. 3  illustrates an exemplary single antenna cut from the base material of  FIG. 2 . The antenna  20  includes a slender body  22  provided with two ends  26  and  28 . A covering layer  228  is provided on the substrate and covering the conductors, (see  FIG. 4 ). The covering layer  228  is removed from the ends  26  and  28  to expose the conductors to allow connection to a connector  30  (see  FIG. 6 ). The antenna body  22  is provided with two fixing parts  24  at locations away from the two ends. Each of the fixing parts  24  is provided with two fixing holes, for fixing the antenna to the electronic apparatus. It can be appreciated by those skilled in the art, that the antenna body may be attached to the electronic apparatus by adhesive, thus not requiring any fixing parts. 
         [0034]      FIG. 4  is a schematic, cross-sectional view along A-A of the antenna of  FIG. 3 . In one embodiment, the antenna includes a single-sided insulating substrate  222 , an adhesive layer  223 , a plurality of parallel conductors  224  formed by conductive traces, an adhesive layer  226  and an insulating covering layer  228 . Both the adhesive layer  223  and the adhesive layer  226  are made of insulating materials. In the production process, the conductors  224  are firstly arranged on the substrate  222  including the adhesive layer  223  by means of printing or etching, then the covering layer  228  including the adhesive layer  226  is attached onto the substrate, and thus the parallel conductors  224  are sandwiched between the substrate  222  and the covering layer  228 . The multiple parallel conductors  224  are electrically insulated from each other. 
         [0035]    In an alternative embodiment, the adhesive layer  223  may be omitted with the conductors  224  being fixed directly on the substrate  222 , such as by printing traces using a conductive ink. 
         [0036]    In an alternative embodiment, the covering layer  228  and the adhesive layer  226  may be replaced by a single layer of insulation ink, thereby further reducing the thickness of the antenna. 
         [0037]    In one embodiment, the substrate  222  is a polymer film, preferably a polyethylene terephthalate (PET, commonly known as Dacron) film. Alternatively, the substrate  222  is a flexible film with a thickness between 12 μm and 125 μm. As a matter of course, the substrate  222  may be thicker as needs dictate. It can be appreciated that the substrate  222  may be other variations of polymer film, including but not limited to polycarbonate, polyethylene napthalate (PEN), polyimide, and polyvinyl chloride (PVC). The substrate  222  may be transparent or opaque and colored, for example, black or white. 
         [0038]    The adhesive layers  223  and  226  are preferably heat-sensitive adhesive layers. The adhesive layer  223  is configured to attach the conductors  224  to the substrate  222 . Alternatively, the adhesive may also be a liquid adhesive such as epoxy resin, or moisture cured polyurethane. The liquid adhesive is firstly placed or printed between the single-sided substrate  222  and the conductors  224 , then the liquid adhesive is cured by wet energy, thermal energy, or ultraviolet light energy, and thus a permanent bond is formed between the single-sided substrate  222  and the conductors  224 . Although these types of adhesives are not pressure sensitive, they can work according to the same principle. Depending on the material of the substrate  222 , different pressure-sensitive adhesives having particular adhesive properties may be used, for example, a customized pressure-sensitive adhesive specially developed for particular adhesive requirements. 
         [0039]      FIGS. 5 a  to 5 c    are schematic diagrams of an RFID antenna according to one embodiment of the present invention, where the covering layer  228  of the antenna body has been omitted for clarity of description. The conductors  224  are arranged on the slender substrate in a parallel manner. One end of the substrate  222 , has conductor ends “A”, “B”, “C” and “D” of the conductors and the other end has conductor ends “a”, “b”, “c” and “d” of the conductors. The antenna body  22  is curled spatially, that is, the antenna body  22  is wrapped around the electronic apparatus (not shown in the Figures). The ends “A”, “B”, “C” and “D” of the conductors correspond to the other ends “a”, “b”, “c” and “d” of the conductors as the ends of the substrate are brought together and connected to a double-sided connector  30  (see  FIG. 6 ). Thus, the conductors form a complete helical coil as the connector joins together the respective ends of the conductors. A pin of the connector corresponding to the end “a” and a pin of the connector corresponding to the end “D”, as ends of the antenna, are connected to the electronic apparatus, thereby eliminating the need to use a double-sided substrate with bridging of the conductors by means of through holes. 
         [0040]      FIG. 6  and  FIG. 7  show a specific connection application between the RFID antenna and the connector  30 .  FIG. 6  illustrates the preferred double-sided connector  30 , which has advantages of simple structure, convenient batch manufacturing and low cost for manufacturing. The connector  30  includes a connector body  32  provided with four upper conductive pins  36  and four lower conductive pins  34 . The upper conductive pins  36  are respectively in communication with the lower conductive pins  34  inside the connector  30 , that is, the pins “a”, “b”, “c” and “d” are respectively connected to the pins “A”, “B”, “C” and “D”. During assembly, the ends “a”, “b”, “c” and “d” of the conductors  224  are respectively connected to the pins “a”, “b”, “c” and “d” of the connector  30 , and the ends “A”, “B”, “C” and “D” of the conductors  224  are respectively connected to the pins “A”, “B”, “C” and “D” of the connector  30 . Since the upper and lower conductive pins of the connector are connected together, the ends “A”, “B”, “C” and “D” of the conductors are electrically connected to the other ends “a”, “b”, “c” and “d” of the conductors, to form the coil shown in  FIG. 5 . A manufacturer only needs to lead out the pins “a” and “D” of the connector as two terminals of the antenna to be connected to the circuit board of the electronic apparatus.  FIG. 7  illustrates the schematic structural of the connection between a pair of pins of the connector  30  and the conductors  224  at corresponding antenna ends. The covering layer  228  and the adhesive layer  226  on the antenna ends are removed to expose the conductors  224 . The substrate  222  at the antenna ends  26  is overlapped with the substrate  222  on the antenna ends  28 , and they are inserted into a U-shaped metal clip  38  with the arms of the clip forming the pair of pins of the connector  30 , so that the ends of two conductors  224  are electrically connected together. 
         [0041]      FIG. 8  is a schematic structural view of a POS device using an RFID antenna according to one embodiment of the present invention. The POS device  40  includes a slot into which a credit card  44  may be inserted. The display screen of the POS device is provided with a columnar body  42 . The antenna  20  is wrapped around the columnar body  42 , and a circuit board (not shown) is arranged inside the POS device, a connector  30  is arranged on the circuit board, the two ends of the antenna are connected to the connector  30  to complete the assembly. When using the POS device, the credit card of a user may be in contact communication with the POS device by the slot, or the credit card may be placed near the antenna  20  and be in non-contact communication with the POS device via the antenna  20 . 
         [0042]    The present invention provides antennas that are arranged spatially, hence, bridging of coils of the antenna is avoided, thus the production cost is reduced and the production efficiency is improved. 
         [0043]    It can be appreciated that the POS device is only a preferred application of the electronic apparatus, and the antenna according to the disclosure may also be used in other electronic apparatuses which need to use a coil antenna. 
         [0044]    In the description and claims of the present application, each of the verbs “comprise”, “include”, “contain” and “have”, and variations thereof, are used in an inclusive sense, to specify the presence of the stated item or feature but do not preclude the presence of additional items or features. 
         [0045]    It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. 
         [0046]    The embodiments described above are provided by way of example only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined by the appended claims.