Patent Publication Number: US-2010113118-A1

Title: Rfid-incorporated game card and manufacturing method thereof

Description:
TECHNICAL FIELD 
     The present invention relates to game cards such as playing cards and hanafuda (Japanese playing cards) and particularly to RFID-incorporated game cards. 
     BACKGROUND ART 
     In recent years, as the development of RFID tags has been advanced, the use of RFID-incorporated game cards and systems using such cards have been proposed for the purpose of alleviating point calculation process or preventing fraudulent conduct. For example, JP 2005-342175 A discloses (e.g., in paragraph [0018]) game cards each including two thin plastic plates with an IC tag and an antenna held therebetween. 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     Ordinary playing cards without RFID tags are produced by laminating two sheets such as plastic sheets and paper sheets and the cards generally have a thickness of about 0.3 mm. However, IC chips and antennas for RFID tags distributed today are each about as thick as 0.03 mm. Therefore, if an IC tag and an antenna are held between two such plastic sheets as in the disclosure of JP 2005-342175 A, the surface layers of the playing card may have irregularities. 
     In order to guarantee fairness in games, game cards such as playing cards, especially those used in a place like casino, must totally lack individuality so that the cards cannot be distinguished from one another when viewed from the back. If there are irregularities on the surface layer of a card, such a demand cannot be met. 
     In view of the above-described problem, it is therefore an object of the present invention to provide an RFID tag-incorporated game card having no irregularities on the surface layers. 
     Means for Solving the Problems 
     In order to achieve the above-described object, a game card according to the present invention has an RFID tag held between at least two sheets, and the RFID tag is held between the above-described at least two sheets while the RFID tag is incorporated in an intermediate layer having an approximately uniform thickness (a first aspect). According to the first aspect, the incorporation of the RFID tag in the intermediate layer having an approximately uniform thickness allows a game card without irregularities on the surface layers to be obtained when the RFID tag is incorporated. 
     In the game card according to the first aspect, the intermediate layer preferably includes the RFID tag and at least two base films arranged to hold the RFID tag therebetween (a second aspect). Alternatively, the intermediate layer preferably includes a base film having the RFID tag embedded therein so that the surface of the tag does not protrude (a third aspect). In any of the aspects, a game card without irregularities on the surface layers can be provided even when an RFID tag is incorporated. 
     According to the second or third aspect, the base film is preferably colored black (a fourth aspect). Alternatively, in the first to third aspects, the sheets and the intermediate layer are preferably adhered to each other using a black adhesive (a fifth aspect). Otherwise, in the second aspect, at least two base films are preferably adhered to each other using a black adhesive (a sixth aspect). According to the fourth and fifth aspects, marks, numbers or the like on the front surface can be prevented from being recognized through the back surface. 
     In the game card according to the first aspect, the intermediate layer is preferably an adhesive layer that adheres the above-described at least two sheets (a seventh aspect). According to this aspect, the intermediate layer also serves as an adhesive layer, the thickness of the game card is not increased when the RFID tag is incorporated. In addition, in the seventh aspect, the adhesive layer is preferably colored black (an eighth aspect). In this way, marks, numbers or the like on the front surface can be prevented from being recognized through the back surface. 
     Furthermore, in order to achieve the above-described object, a game card according to the present invention includes at least two sheets and an RFID tag held between the sheets, at least one of the-above described at least two sheets has a degree of plasticity that absorbs the thickness of the RFID tag (a ninth aspect). According to the ninth aspect, the RFID tag is held between at least two sheet including a sheet having a degree of plasticity that absorbs the thickness of the tag, and therefore a game card without irregularities on the surface layers can be provided even when the RFID tag is incorporated. In the ninth aspect, a sheet including foams for example may be used as the sheet having plasticity (a tenth aspect). 
     In the ninth or tenth aspect, the sheets are preferably adhered to each other using a black adhesive with the RFID tag interposed therebetween (an eleventh aspect). In this way, marks, numbers or the like on the front surface can be prevented from being recognized from the back surface side. 
     In order to achieve the above-described object, a first method of manufacturing a game card according to the present invention is a method of manufacturing a game card having an RFID tag-incorporated intermediate layer held between at least two sheets, the intermediate layer has an approximately uniform thickness, and the method includes the steps of having a plurality of RFID tags incorporated in the intermediate layer, forming a layered body having the intermediate layer held between at least two sheets, and cutting individual game cards from the layered body. According to the manufacturing method, a game card without irregularities on the surface layers can efficiently be produced even when an RFID tag is incorporated. 
     In order to achieve the above-described object, a second method of manufacturing a game card according to the present invention is a method of manufacturing a game card having an RFID tag held between at least two sheets including a sheet having a degree of plasticity that absorbs the thickness of the RFID tag, and the method includes the steps of providing a plurality of RFID tags on at least one of the two sheets, forming a layered boy produced by providing at least one sheet on the sheet having the plurality of RFID tags provided thereon, and cutting individual game cards out from the layered body. Also according to the manufacturing method, a game card without irregularities on the surface layers can efficiently be produced even when an RFID tag is incorporated. 
     The first or second manufacturing method preferably includes the step of printing a mark and/or a number on the surfaces of the sheets before the step of forming the layered body. Furthermore, the step of recording the plurality of RFID tags with pieces of information different from one another that correspond to the mark and/or the number printed on the sheets is preferably included. 
     Effects of the Invention 
     According to the present invention, an RFID tag-incorporated game card without irregularities on the surface layers can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a plan view of a playing card according to a first embodiment of the present invention. 
         FIG. 1B  is a sectional view taken along A-A′ in  FIG. 1A . 
         FIG. 2  is a process view schematically showing essential steps in the process of manufacturing playing cards according to the first embodiment. 
         FIG. 3  is a sectional view of a modification of the playing card according to the first embodiment. 
         FIG. 4  is a sectional view of the structure of a playing card according to a second embodiment. 
         FIG. 5  is a sectional view of the structure of a playing card according to a third embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Now, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     First Embodiment 
       FIG. 1  includes views showing the structure of a playing card  10  as a game card according to a first embodiment of the present invention,  FIG. 1A  is a plan view of the playing card  10  and  FIG. 1B  is a sectional view of the playing card  10  taken along A-A′ in  FIG. 1A . Note that in  FIGS. 1A ,  1 B and  2  and the other figures, elements of each playing card are not drawn in actual size. 
     The playing card  10  according to the present embodiment has marks and numbers printed on one surface (the front surface that is not shown) and an arbitrary pattern or design such as a geometrical pattern printed on the back surface as shown in  FIG. 1A  and looks exactly like a conventional playing card in appearance. The playing card  10  however includes an intermediate layer  12  including an RFID tag  121  between two surface layer sheets  11   a  and  11   b  that form the front and back surfaces of the playing card as shown in  FIG. 1B . The intermediate layer  12  has a substantially uniform thickness across the entire surface. The surface layer sheets  11   a  and  11   b  each have a thickness of about 75 μm, and the intermediate layer  12  has a thickness of about 150 μm. Paper or a resin film such as vinyl chloride and PET (polyethylene terephthalate) is used for the surface layer sheets  11   a  and  11   b.    
     In the intermediate layer  12 , the RFID tag  121  is held between two base films  122   a  and  122   b  having plasticity. The RFID tag  121  includes an IC chip and an antenna for radio communication (both not shown). The IC chip of the RFID tag  121  can be recorded with various kinds of information. Examples of such information include information indicating the marks and/or numbers printed on the front surface of the playing card  10 , information indicating the manufacturer of the playing card  10 , information indicating the owner of the playing card  10 , information indicating the date of manufacture of the playing card  10 , information indicating the date on which the playing card  10  was obtained by the owner, information indicating the period in which the playing card  10  can effectively be used and information indicating the place where the playing card  10  can effectively be used. Needless to say, information that can be recorded on the IC chip of the RFID tag  121  is not limited to the above-described examples. Note that the marks and/numbers are printed on the surface layer sheets  11   a  and  11   b,  and these marks and/or numbers are printed before the RFID tag  121  is held between the two surface layer sheets  11   a  and  11   b  that form the front and back surfaces of the card, so that printing misregistration or the like may be minimized. A plurality of RFID tags  121  include different kinds of information among one another, and marks and/or numbers printed on the surface layer sheets  11   a  and  11   b  correspond to the tags, so that manufactured cards can more surely prevent misconduct. 
     Examples of the material of the base films  122   a  and  122   b  preferably include paper, vinyl chloride and polyethylene terephthalate, while the material is not limited to the above. More specifically, the base films  122   a  and  122   b  need only have a degree of plasticity that allows the films to conform to the contour of the RFID tag  121  held between them with the smallest possible gap and the thickness of the RFID tag  121  to be absorbed so that the thickness of the layered body (intermediate layer  12 ) is substantially uniform across the entire surface and the surface layers of the playing card  10  have no irregularities. In addition, when a thermal press-bonding step is included in the process of manufacturing the playing card  10 , the base films  122   a  and  122   b  also serve to protect the RFID tag  121  against heat and pressure during the thermal press-bonding step. 
     Note that the base films  122   a  and  122   b  are preferably colored black in order to prevent light from being transmitted therethrough. Alternatively, a black adhesive that absorbs light is preferably used to laminate the base films  122   a  and  122   b  to each other. Furthermore, a black adhesive is preferably used to laminate the intermediate layer  12  and the surface layer sheets  11   a  and  11   b  to each other. According to the preferred arrangements, the following effects are provided. 
     More specifically, the playing card  10  according to the present embodiment has the intermediate layer  12  inserted therein and therefore the surface layer sheets  11   a  and  11   b  must be thinner than those in the conventional example in order to make the total thickness of the playing card  10  about equal to that of the conventional playing card (normally about 300 μm). In other words, in the conventional playing card produced by laminating two surface layer sheets, the thickness of one surface layer sheet is about 150 μm, while in the playing card according to the present embodiment, the surface layer sheets  11   a  and  11   b  each have a thickness of 75 μm, which is about half the thickness of the conventional sheet as described above. When the surface layer sheets  11   a  and  11   b  are reduced in thickness in this way, the numbers and signs on the front surface may be seen through the back surface in some cases. Therefore, the use of the black base film or adhesive as described above can prevent the front surface from being seen through even when the surface layer sheets  11   a  and  11   b  are reduced in thickness. 
     Now, with reference to  FIG. 2 , an example of a method of manufacturing the playing card  10  will be described. In this example, an adhesive (not shown) is applied on a base film  122   b,  and a plurality of RFID tags  121  are arranged at prescribed intervals as shown in  FIG. 2A . Then, another base film  122   a  is placed thereon, and then the two films  122   a  and  122   b  are laminated to each other by the adhesive. In this way, as shown in  FIG. 2B , a layered body  12 ′ having the plurality of RFID tags  121  held between the two base films  122   a  and  122   b  is formed. Note that  FIGS. 2A and 2B  show an example only and the number of RFID tags  121  arranged on the base film  122   b  is arbitrary. 
     Now, patterns or designs for the front and back surfaces are printed on the surface layer sheets  11   a  and  11   b.  Then, as shown in  FIG. 2C , the layered body  12 ′ is held between the surface layer sheets  11   a  and  11   b  after printing, and a layered body  12 ″ as shown in  FIG. 2D  is formed by adhesion with an adhesive or fusion press bonding by heating. In this way, printing to the surface layer sheets  11   a  and  11   b  is carried out before the layers are laminated to the layered body  12 ′ having the RFID tags  121  incorporated therein, so that the RFID tags  121  can be prevented from being destroyed by pressure otherwise applied by the rollers or the like of a printer. In consideration of the possibility that the RFID tags  121  still cause printing misregistration even if they are held between the base films  122   a  and  122   b  during the pressing process between the rollers of the printer, printing to the surface layer sheets  11   a  and  11   b  is preferably carried out before they are laminated to the layered body  12 ′ having the RFID tags  121  incorporated therein. 
     Then, as shown in  FIG. 2D , playing cards  10  are cut out from the layered body  12 ″ by punching processing as shown in  FIG. 2D . Through the above-described process, the playing cards  10  can be manufactured efficiently. Note that before or after the step in  FIG. 2C , the printing surfaces of the surface layer sheets  11   a  and  11   b  may be subjected to over-coating. Note however that over-coating treatment carried out at high temperatures is preferably performed before the step in  FIG. 2C  in order to prevent the RFID tags  121  from being destroyed by the heat. 
     Note that the RFID tags  121  provided on the base film  122   b  in  FIG. 2A  are each produced by forming an IC chip and an antenna on a base material such as a resin sheet having a relatively small area. However, if for example a product including a plurality of RFID tags  121  formed on a single base material is commercially available from an RFID tag manufacturer, the base material may be used as the base film  122   b  and the other base film  122   a  may be provided thereon, so that the layered body  12 ′ may be formed. 
     As in the foregoing, in the playing card  10  according to the present embodiment, the intermediate layer  12  having the RFID tag  121  incorporated therein is formed to have a substantially uniform thickness. Therefore, the RFID tag  121  may be incorporated without irregularities on the surface layers of the card  10 . 
     Note that according to the present embodiment, the RFID tag  121  is held between the two surface layer sheets  11   a  and  11   b  by way of illustration, while three or more surface layer sheets may be used. In  FIG. 1B , the two base films  122   a  and  122   b  are used to hold the RFID tag  121  as an example, while three or more base films may be used. 
     As shown in  FIG. 3 , the RFID tag  121  may be embedded so that its surface is flush with the surface of a base film  122   c  and the obtained structure may be used as the intermediate layer  12 . Also in this example, the base film  122   c  is preferably colored black or the intermediate layer  12  and the surface layer sheets  11   a  and  11   b  are preferably adhered to each other using a black adhesive. 
     Second Embodiment 
       FIG. 4  is a sectional view of the structure of a playing card  20  as a game card according to a second embodiment of the present invention. 
     As shown in  FIG. 4 , in the playing card  20  according to the present embodiment, an intermediate layer  22  including an RFID tag  121  is held between surface layer sheets  11   a  and  11   b.  The intermediate layer  22  includes the RFID tag  121  and an adhesive layer  222  having the RFID tag  121  embedded so that the tag does not protrude beyond the surface. 
     The adhesive layer  222  is made of an adhesive that is colored black and has a substantially uniform thickness. The thickness is for example about 40 μm. The surface layer sheets  11   a  and  11   b  each have a thickness of about 130 μm. Therefore, the total thickness of the playing card  20  is about 300 μm. 
     The playing card  20  can be produced in the following manner. An adhesive is applied on the surface layer sheet  11   b  to form an adhesive layer  222 , an RFID tag  121  is embedded therein and the surface sheet  11   a  is placed thereon, followed by appropriate pressurizing, so that the adhesive layer  222  is solidified. Note that for the same reason as that described in connection with the first embodiment, printing is preferably carried out in advance to the surface layer sheets  11   a  and  11   b.  Alternatively, an adhesive layer  222  may be provided at each of the surface layer sheets  11   a  and  11   b,  an RFID tag  121  may be held between the adhesive layers  222 , and then the adhesive layers  222  may be solidified. 
     Note that similarly to the manufacturing process described in connection with the first embodiment, a plurality of RFID tags  121  may be embedded in the surface layer sheet  11   b  provided with an adhesive, the surface layer sheet  11   a  may be laminated thereon, and then cards  20  may be cut out by punching processing, so that the production efficiency can be improved. 
     As in the foregoing, in the playing card  20  according to the present embodiment, the intermediate layer  22  including the RFID tag  121  is formed to have a substantially uniform thickness. Therefore, the RFID tag  121  can be incorporated without irregularities on the surface layers of the playing card  20 . 
     In the playing card  20 , the intermediate layer  21  includes the adhesive layer  222  that serves as an adhesive layer, so that the card can be prevented from being increased in thickness by the incorporation of the RFID tag  121 . 
     Note that according to the present embodiment, the RFID tag  121  is held between the two surface layer sheets  11   a  and  11   b  by way of illustration, while three or more surface layer sheets may be used. 
     Third Embodiment 
       FIG. 5  is a sectional view of the structure of a playing card  30  as a game card according to a third embodiment of the invention. 
     As shown in  FIG. 5 , in the playing card  30  according to the present embodiment, RFID tag  121  is held between surface layer sheets  31   a  and  31   b  with plasticity. The surface layer sheets  31   a  and  31   b  need only have a degree of plasticity that allows the sheets to conform to the contour of the RFID tag  121  held between them with the smallest possible gap and the thickness of the RFID tag  121  to be absorbed so that the thickness is substantially uniform across the entire surface and the surface layers of the playing card  30  are free of irregularities. As shown in  FIG. 5 , a resin sheet having a lot of foams  311  may be used for the surface layer sheets  31   a  and  31   b.    
     The surface layer sheets  31   a  and  31   b  are preferably adhered to each other using a black adhesive (not shown). As described in connection with the first embodiment, this can prevent marks or letters on the front surface from being seen through the back surface. 
     According to the present embodiment, similarly to the manufacturing process described in connection with the first embodiment, a plurality of RFID tags  121  may be provided on the surface layer sheet  31   a,  the surface layer sheet  31   b  may be laminated thereon, and then playing cards  30  may be cut out by punching processing. In this way, the playing cards  30  can be produced efficiently. As described in connection with the first embodiment, printing is preferably carried out in advance to the surface layer sheets  31   a  and  31   b.    
     Note that a printed sheet may be placed on the surface layer sheets  31   a  and  31   b  instead of directly carrying out printing to the surface layer sheets  31   a  and  31   b.    
     Note that the RFID tag  121  may be produced by forming an IC chip and an antenna on a base material such as a resin sheet having a relatively small area, while, alternatively, if for example an RFID tag sheet having a plurality of RFID tags  121  formed on a single base material is commercially available from an RFID tag manufacturer or the like, the RFID tag sheet may be provided on the surface layer sheet  31   b,  the other surface layer sheet  31   a  may be laminated thereon, and then playing cards  30  may be cut out by punching processing. 
     Note that in the foregoing description, the surface layer sheets  31   a  and  31   b  both have plasticity, but only one of the surface layer sheets  31   a  and  31   b  may have plasticity, provided that the thickness of the RFID tag  121  can be absorbed. 
     As in the foregoing, in the playing card  30  according to the present embodiment, the RFID tag  121  is held between the surface layer sheets having plasticity. In this way, the RFID tag  121  can be incorporated without irregularities on the surface layers of the playing card  30 . 
     In addition, in each of the embodiments described above, the playing card is shown as an example of the game card according to the invention, while the invention is applicable to various kinds of game cards other than the playing card. 
     INDUSTRIAL APPLICABILITY 
     The invention has industrial applicability in the field of game cards.