JP6481517B2 - Non-contact information medium - Google Patents

Description

  The present invention relates to a non-contact type information medium, and more particularly to a non-contact IC card, a non-contact IC tag, and the like that perform wireless communication using an HF band signal.

  A non-contact IC card that performs wireless communication using a signal in an HF band (for example, 13.56 MHz) is known (for example, see Patent Document 1). In the non-contact IC card described in Patent Document 1, a planar substrate connected to both ends of the planar coil antenna or the planar coil antenna is obtained by processing a film substrate having metal foils bonded to both sides by etching or the like. While forming on one surface of the substrate, another plate electrode for forming a capacitor is formed on the other surface of the film substrate so as to face these plate electrodes. In this non-contact IC card, the flat plate electrodes formed on the other surface of the film base are connected to each other by a conductor wiring (jumper) so that the inner terminal portion and the outer terminal portion of the planar antenna coil are electrically connected in a high frequency region. Be made.

JP 2004-355442 A

  By the way, in the non-contact information medium of the type which comprises a capacitor | condenser by the flat electrode which opposes like the non-contact IC card of patent document 1, when it is going to change the capacity | capacitance of a capacitor | condenser, the thickness etc. of a film base material are included It is necessary to change the shape of the plate electrode by redesigning or cutting the conductor.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a non-contact type information medium capable of easily adjusting the capacitance of a capacitor constituted by opposing flat plate electrodes.

  The present invention relates to a non-contact type information medium. The non-contact type information medium includes a film base made of a dielectric, an antenna coil disposed on at least one surface of the film base, and wirelessly via the antenna coil. An IC chip that performs communication processing, a first flat plate electrode that is connected to the antenna coil and disposed on one surface of the film base, and faces the first flat plate electrode in the thickness direction across the film base And a second flat plate electrode disposed on the other surface of the film base. In this non-contact type information medium, the film substrate includes an intermediate substrate made of a dielectric, a first adjustment dielectric layer made of a dielectric and formed on one surface of the intermediate substrate, and a dielectric And a second adjustment dielectric layer formed on the other surface of the intermediate substrate.

  In this non-contact type information medium, the film base material sandwiched between the first and second flat plate electrodes has at least a three-layer structure of an intermediate base material and first and second adjustment dielectric layers. For this reason, the thickness of the film substrate made of a dielectric band, that is, the separation distance between the first and second flat plate electrodes can be easily adjusted, for example, by changing the thickness of the first or second adjustment dielectric layer. Therefore, the capacitance of the capacitor by the first and second plate electrodes can be easily adjusted without changing the shape of the electrode pattern of the plate electrodes constituting the capacitor. In addition, since this non-contact type information medium is configured to conduct by a capacitor formed between the first flat plate electrode connected to the antenna coil and the second flat plate electrode arranged on the back surface side, Compared with the case where the start point and end point of the antenna coil are directly connected to the backside conductor pattern, the manufacturing and inspection processes can be simplified, and the reliability with respect to conduction can be improved.

  In the non-contact type information medium, the relative dielectric constant of the dielectric constituting the first and second adjustment dielectric layers may be equal to or greater than the relative dielectric constant of the dielectric constituting the intermediate substrate. preferable. In this case, it is possible to easily adjust the capacitance of the capacitor by the first and second plate electrodes even if the first and second adjustment dielectric band layers are thin.

  In the non-contact information medium, the first and second adjustment dielectric layers are preferably thinner than the intermediate base material. In this case, since the adjustment dielectric layer for adjusting the capacitance of the capacitor by the first and second plate electrodes can be thinned, it is possible to suppress variations in the total thickness of the film base material for each product. It becomes.

  In the above non-contact type information medium, the dielectric material constituting the first and second adjustment dielectric layers may be different from or the same as the dielectric material constituting the intermediate substrate. .

  In the non-contact type information medium, it is preferable that the thickness of the metal foil constituting the antenna coil is thicker than the thickness of the metal foil constituting the second flat plate electrode. In this case, the electric resistance in the antenna coil can be lowered, and the radiation efficiency of the antenna of the non-contact type information medium can be improved.

  In the non-contact type information medium, the first and second adjustment dielectric layers may be formed by applying a dielectric material to the intermediate base material and curing it. In this case, the thickness and the like of the first and second adjustment dielectric layers can be easily adjusted, so that the capacitance of the capacitor by the first and second plate electrodes can be easily adjusted.

  In the non-contact information medium, the area of the second plate electrode in the plane direction is larger than the area of the first plate electrode in the plane direction, and is orthogonal to the plane direction of the first and second plate electrodes. When viewed from the direction, the first plate electrode may be included in the second plate electrode. When each of the first and second flat plate electrodes is formed on either surface of the base film, the position of both flat plate electrodes may be slightly deviated from the design value due to manufacturing errors or the like. Thus, even when the arrangement positions of the first and second plate electrodes are slightly deviated from the design values, a capacitor having a predetermined capacitance value can be obtained. Contrary to the above, the area in the plane direction of the first plate electrode is larger than the area in the plane direction of the second plate electrode, and the direction is orthogonal to the plane direction of the first and second plate electrodes. When viewed from above, the second plate electrode may be included in the first plate electrode. However, since the antenna coil is also formed on the side where the first flat plate electrode is formed, it is easy to reduce the size of the non-contact type information medium as a whole by making the second flat plate electrode larger. Become.

  In the non-contact type information medium, the first and second flat plate electrodes are formed on the flow path of the current flowing through the antenna coil to form a part of the coil pattern, and from the amount of current flowing through the first flat plate electrode In the region where the amount of current flowing through the second plate electrode is larger, the area of the second plate electrode is larger than that of the first plate electrode. In a region where the amount of current flowing through the first plate electrode is larger than the amount of current flowing through the first plate electrode, the area of the first plate electrode is larger than that of the second plate electrode. Good. In this way, when the first and second flat plate electrodes are formed on the flow path flowing through the antenna coil to constitute a part of the coil pattern, the flat plate electrode can be used as a part of the antenna, and the limited antenna Under the formation region, the number of turns of the coil can be increased and the opening area of the antenna can be increased. Moreover, it becomes possible to enlarge the formation area of other members, such as an antenna coil, by making a flat electrode small in the location where the amount of flowing electric currents is small.

  In the non-contact type information medium, the first and second flat plate electrodes are formed on the flow path of the current flowing through the antenna coil to form a part of the coil pattern, and in the cross section of the electrode on the first flat plate electrode In the region where the average current density in the electrode cross section on the second plate electrode is larger than the average current density, the area of the second plate electrode is larger than that of the first plate electrode. In the region where the average current density in the electrode cross section on the first flat plate electrode is larger than the average current density in the electrode cross section on the second flat plate electrode, the first flat plate electrode May be formed to have a larger area than the second flat plate electrode. In this way, when the first and second flat plate electrodes are formed on the flow path flowing through the antenna coil to constitute a part of the coil pattern, the flat plate electrode can be used as a part of the antenna, and the limited antenna Under the formation region, the number of turns of the coil can be increased and the opening area of the antenna can be increased. Moreover, it becomes possible to enlarge the formation area of other members, such as an antenna coil, by making a flat electrode small in the location where the amount of flowing electric currents is small.

  ADVANTAGE OF THE INVENTION According to this invention, the non-contact-type information medium which can adjust easily the capacity | capacitance of the capacitor | condenser comprised by the opposing flat electrode can be provided.

FIG. 1 is a diagram showing an internal configuration of a non-contact IC card according to the first embodiment of the present invention, (a) is a diagram from the top surface side, and (b) is a diagram from the back surface side. is there. 2A is a cross-sectional view taken along line II (a) -II (a) of the non-contact IC card shown in FIG. 1, and FIG. 2B is a cross-sectional view of the non-contact IC card shown in FIG. It is sectional drawing along the II (b) -II (b) line. FIG. 3 is a circuit diagram showing an equivalent circuit of the non-contact IC card shown in FIG. 4A and 4B are diagrams showing a modification of the non-contact IC card according to the first embodiment of the present invention, in which FIG. 4A shows a cross-sectional view, and FIG. 4B shows the size relationship of each plate electrode. It is a figure shown typically. FIG. 5 is a view showing another modification of the non-contact IC card according to the first embodiment of the present invention, where (a) shows a cross-sectional view and (b) shows the size of each plate electrode. It is a figure which shows a relationship typically. 6A and 6B are diagrams showing the internal configuration of the non-contact IC card according to the second embodiment of the present invention, wherein FIG. 6A is a diagram from the top surface side, and FIG. 6B is a diagram from the back surface side. is there. FIG. 7 is a cross-sectional view schematically showing the flow of current between the plate electrodes of the non-contact IC card shown in FIG. FIG. 8 is a circuit diagram showing an equivalent circuit of the non-contact IC card shown in FIG. FIG. 9 is a view showing a modification of the non-contact IC card according to the second embodiment of the present invention, in which (a) shows a flat plate electrode on the front side, and (b) shows a flat plate electrode on the back side. (C) shows a state in which both plate electrodes are arranged to face each other. FIG. 10 is a view showing another modification of the non-contact IC card according to the second embodiment of the present invention, in which (a) shows a flat plate electrode on the front surface side, and (b) shows a flat plate on the back surface side. An electrode is shown, (c) shows the state which has arrange | positioned both plate electrodes facing each other.

  Hereinafter, a non-contact IC card according to the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals may be used for the same elements or elements having the same function, and redundant description is omitted.

[First Embodiment]
First, a non-contact IC card (non-contact information medium) according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an internal configuration of a non-contact IC card according to the first embodiment of the present invention, (a) is a diagram from the top surface side, and (b) is a diagram from the back surface side. is there. 2A is a cross-sectional view taken along line II (a) -II (a) of the non-contact IC card shown in FIG. 1, and FIG. 2B is a cross-sectional view of the non-contact IC card shown in FIG. It is sectional drawing along the II (b) -II (b) line. FIG. 3 is a circuit diagram showing an equivalent circuit of the non-contact IC card shown in FIG. Note that FIG. 1B shows a reverse side view that is inverted about the center line in the longitudinal direction shown in FIG.

  The non-contact IC card 10 can perform non-contact communication using an RFID technology with an external read / write device (not shown) such as a reader / writer mainly using a signal in an HF band (for example, 13.56 MHz). A wireless communication medium with RFID. As shown in FIGS. 1 and 2, the non-contact IC card 10 includes a rectangular film substrate 11. An IC chip 12, an antenna coil 13, and first flat plate electrodes 14a and 14b are disposed on the front surface 11a of the film substrate 11, and a second flat plate electrode 16a is disposed on the back surface 11b of the film substrate 11. 16b and jumper lines 17 are arranged.

  The film base material 11 is a base material having, for example, a three-layer structure made of a dielectric, and an intermediate base material having insulation and durability such as polyethylene naphthalate (PEN) and polyethylene terephthalate copolymer (PET-G). 11c is provided as a main base material. First and second adjustment dielectric layers 11d and 11e having a thickness smaller than that of the intermediate base material 11c are provided on both front and back surfaces of the intermediate base material 11c. The details of the first and second adjustment dielectric layers 11d and 11e will be described later.

  Metal foils are bonded to the front and back surfaces 11a and 11b of the film base 11 before being processed by etching or the like, and these metal foils are processed by etching or the like so that the antenna coil 13, the first flat plate electrode 14a, 14b, second plate electrodes 16a and 16b, and jumper wires 17 are formed. The metal foil disposed on each of the front and back surfaces 11a and 11b of the film base 11 may have the same thickness. However, in the antenna coil 13, the coils are disposed at a narrow pitch. In order to reduce the electrical resistance, the thickness of the metal foil on the surface 11a side where the antenna coil 13 is arranged may be made thicker than the thickness of the metal foil on the back surface 11b side where the second flat plate electrodes 16a and 16b are arranged. .

  The IC chip 12 is composed of, for example, an IC tag that stores ID information. The IC chip 12 is disposed on the path of the antenna coil 13 on the surface 11 a of the film base 11, and both terminals thereof are connected to the antenna coil 13. The IC chip 12 performs wireless communication processing through the conductive antenna coil 13 and exchanges predetermined signals with an external read / write device.

  The antenna coil 13 is a planar spiral antenna for electromagnetically coupling with an antenna of an external read / write device such as a reader / writer to perform non-contact wireless communication. The antenna coil 13 exchanges signals and receives power in a non-contact state by this wireless communication. The antenna coil 13 is formed from a conductor (metal foil) disposed on the surface 11 a of the film base 11. Specifically, for example, a pattern is formed by etching a copper foil or an aluminum foil having a thickness of 5 μm to 50 μm bonded to the surface 11 a side of the film substrate 11 having a thickness of 15 μm to 50 μm. Such an antenna coil 13 is connected to the plate electrode 14a at the outer end thereof and is connected to the plate electrode 14b at the inner end thereof.

  The first flat plate electrodes 14a and 14b are rectangular planar electrodes, respectively, and are arranged in parallel with one end side on the surface 11a of the film substrate 11 with a part of the antenna coil 13 sandwiched therebetween. Be placed. Since the plate electrode 14b is formed inside the antenna coil 13, its electrode area is smaller than that of the plate electrode 14a. However, the electrode areas of the plate electrodes 14a and 14b may be the same, or the plate electrode 14b may be larger than the plate electrode 14a. Further, as described above, the plate electrode 14 a is connected to the outer end of the antenna coil 13, and the plate electrode 14 b is connected to the inner end of the antenna coil 13. The first flat plate electrodes 14 a and 14 b are patterned by etching the metal foil bonded to the surface 11 a side of the film base 11, similarly to the antenna coil 13. Second plate electrodes 16a and 16b and a jumper line 17 which will be described later are formed in the same manner.

  Each of the second plate electrodes 16a and 16b is a rectangular planar electrode, and one end side on the back surface 11b of the film substrate 11 with a part of the region corresponding to the antenna coil 13 sandwiched therebetween. Are arranged in parallel. Since the plate electrode 16b is formed inside a region corresponding to the antenna coil 13 (a region indicated by the dotted line in FIG. 1B), the electrode area is smaller than that of the plate electrode 16a. However, it is not limited to the same as the first flat plate electrodes 14a and 14b. 2A and 2B, the second flat plate electrodes 16a and 16b are formed so as to face the first flat plate electrodes 14a and 14b in the thickness direction of the film base 11. Is done. More specifically, the plate electrode 14a and the plate electrode 16a face each other, and the plate electrode 14b and the plate electrode 16b face each other. With such an opposing arrangement, the first plate electrodes 14a and 14b and the second plate electrodes 16a and 16b form two capacitor portions (see FIG. 3), respectively.

  The plate electrodes 14a and 16a facing each other have the same shape and the same size (area), and the plate electrodes 14b and 16b facing each other have the same shape and the same size. The first flat plate electrodes 14 a and 14 b and the second flat plate electrodes 16 a and 16 b coincide with each other when viewed from the thickness direction of the film base 11. Note that the second plate electrodes 16a and 16b are not connected to the antenna coil 13, unlike the first plate electrodes 14a and 14b.

  The jumper line 17 is a wiring that connects the second flat plate electrodes 16 a and 16 b to each other on the back surface 11 b of the film base 11. Since it is preferable to reduce the electrostatic capacitance between the jumper wire 17 and the opposing antenna coil 13, the width is preferably as narrow as possible, for example, about 1 to 3 mm. With such a jumper wire 17, conduction between the plate electrode 16 a and the plate electrode 16 b is achieved. In the example shown in FIG. 1B, the jumper wire 17 connects the plate electrodes 16a and 16b above the plate electrodes 16a and 16b in the longitudinal direction, but is connected at other portions such as the center. You may make it do.

  The non-contact IC card 10 having such a configuration can be expressed as an equivalent circuit as shown in FIG. That is, as shown in FIG. 3, the non-contact IC card 10 is arranged in the order of the IC chip 12, the antenna coil 13, the first capacitor portions 14a and 16a, the jumper wire 17, and the second capacitor portions 14b and 16b. It consists of a circuit.

  Here, the layer configuration of the film base 11 of the non-contact IC card 10 having such a configuration and the operation effect thereof will be described in more detail with reference to FIGS. 2 (a) and 2 (b).

  As shown in FIGS. 2A and 2B, the film base material 11 constituting the non-contact IC card 10 is made of a dielectric material in addition to the intermediate base material 11c that is the main base material, and the intermediate base material 11c is illustrated. A first adjusting dielectric layer 11d formed on the upper surface; and a second adjusting dielectric layer 11e made of a dielectric and formed on the lower surface of the intermediate substrate 11c. It has a three-layer structure. In the non-contact IC card 10 according to the present embodiment, the film base 11 has such a three-layer structure because the thickness and relative dielectric constant of the first and second adjustment dielectric layers 11d and 11e, etc. By adjusting the capacitance of the capacitor (capacitor) formed by the first and second plate electrodes 14a and 16a and the capacitor (capacitor) formed by the first and second plate electrodes 14b and 16b. This is because the capacitance value can be adjusted by simple means. The first and second adjustment dielectric layers 11d and 11e are layers for adjusting the capacitance value, and are thinner than the intermediate substrate 11c from the viewpoint of reducing the thickness of the non-contact IC card 10. Although it is preferable, it is not necessarily limited to it.

  In order to enable such adjustment of the capacitance value, the dielectric material constituting the first and second adjustment dielectric layers 11d and 11e is, for example, the dielectric of the intermediate substrate 11c made of PET or the like. Although it can be made of a material different from the body material, it may be made of the same material. Examples of the material constituting the first and second adjustment dielectric layers 11d and 11e include polyester resins, polyether resins, polyethylene, polypropylene, and EVA resins. The first and second adjustment dielectric layers 11d and 11e may be formed by applying these dielectric materials on both the front and back surfaces of the intermediate substrate 11c and curing them. When such a manufacturing method is adopted, it is possible to appropriately adjust the thicknesses and materials (that is, relative dielectric constant) of the first and second adjustment dielectric layers 11d and 11e.

  As described above, in the non-contact IC card 10 according to the present embodiment, the film substrate 11 sandwiched between the first and second flat plate electrodes 14a, 14b, 16a, and 16b has the intermediate substrate 11c and the first and second adjustments. It has a three-layer structure of dielectric layers 11d and 11e for use. For this reason, the thickness of the film substrate 11 made of a dielectric, that is, the distance between the first and second flat plate electrodes 14a and 16a and the distance between 14b and 16b, for example, the first or second adjustment dielectric layer 11d. 11e can be easily adjusted by changing the thickness of the first and second electrodes without changing the shape (area) of the electrode patterns of the plate electrodes 14a, 14b, 16a, 16b constituting the capacitor. It is possible to easily adjust the capacitance of the capacitor by the two plate electrodes 14a, 14b, 16a, 16b. In the non-contact IC card 10, conduction is made by a capacitor formed between the first flat plate electrodes 14 a and 14 b connected to the antenna coil 13 and the second flat plate electrodes 16 a and 16 b arranged on the back surface side. Therefore, the manufacturing and inspection process can be simplified and the reliability for conduction can be improved as compared with the case where the starting point and the ending point of the antenna coil 13 are directly connected to the back side conductor pattern. It becomes.

  In the non-contact IC card 10, the relative dielectric constant of the dielectric constituting the first and second adjustment dielectric layers 11d and 11e is equal to or greater than the relative dielectric constant of the dielectric constituting the intermediate substrate 11c. It is. Therefore, it is easy to adjust the capacitance of the capacitor by the first and second flat plate electrodes 14a, 14b, 16a, 16b even if the first and second adjustment dielectric band layers 11d, 11e are thin. Yes.

  In the non-contact IC card 10, the thickness of the first and second adjustment dielectric layers 11d and 11e is smaller than the thickness of the intermediate base material 11c. As described above, the adjustment dielectric layer for adjusting the capacitance of the capacitor by the first and second flat plate electrodes 14a, 14b, 16a, and 16b can be thinned. It becomes possible to suppress variation in the total thickness. In addition, the entire non-contact IC card 10 can be reduced in thickness.

  In the non-contact IC card 10, for example, the first and second adjustment dielectric layers 11d and 11e are formed by applying a predetermined dielectric material to the intermediate substrate 11c and curing it. Yes. For this reason, the thickness and relative dielectric constant of the first and second adjustment dielectric layers 11d and 11e can be easily adjusted, whereby the first and second flat plate electrodes 14a, 14b and 16a can be adjusted. , 16b can easily adjust the capacitance of the capacitor.

  Further, in the non-contact IC card 10, the thickness of the metal foil constituting the antenna coil 13 is thicker than the thickness of the metal foil constituting the second flat plate electrodes 16a and 16b. For this reason, the electrical resistance in the antenna coil 13 can be lowered, and the radiation efficiency of the antenna of the non-contact IC card 10 can be improved.

  In the above embodiment, the planar electrodes 14a and 16a constituting the capacitor of the non-contact IC card 10 have the same area in the planar direction, and the planar electrodes 14b and 16b constituting the other capacitors have the same area in the planar direction. Although the example which corresponds mutually was shown, it is not necessarily limited to this. For example, as shown in FIGS. 4A and 4B, the area in the plane direction of the second plate electrode 16a disposed on the back surface 11b side is larger than the area in the plane direction of the first plate electrode 14a. The first flat plate electrode 14a may be included in the second flat plate electrode 16a when viewed from a direction orthogonal to the planar direction of the first and second flat plate electrodes 14a and 16a. . When each of the first and second flat plate electrodes 14a and 16a is formed on any surface of the film base 11, the positions of the flat plate electrodes 14a and 16a are slightly deviated from the design values due to manufacturing errors or the like. However, with the above configuration, even when the arrangement positions of the first and second flat plate electrodes 14a and 16a are slightly deviated from the design values, a capacitor having a predetermined capacitance value can be obtained. It becomes.

  On the contrary, as shown in FIGS. 5A and 5B, the area of the first plate electrode 14a in the plane direction is larger than the area of the second plate electrode 16a in the plane direction. The second flat plate electrode 16a may be included in the first flat plate electrode 14a when viewed from a direction orthogonal to the planar direction of the first and second flat plate electrodes 14a and 16a. However, since the antenna coil 13 is also formed on the side where the first flat plate electrode 14a is formed, the size of the second non-contact IC card 10 as a whole can be reduced by making the second flat plate electrode 16a larger. It becomes easy to plan. In the above description, the relationship between the areas of the first and second plate electrodes 14a and 16a has been described. The same applies to the relationship between the areas of the first and second plate electrodes 14b and 16b.

[Second Embodiment]
Next, a non-contact IC card according to the second embodiment of the present invention will be described with reference to FIG. 6A and 6B are diagrams showing the internal configuration of the non-contact IC card according to the second embodiment of the present invention, wherein FIG. 6A is a diagram from the top surface side, and FIG. 6B is a diagram from the back surface side. is there. FIG. 7 is a cross-sectional view schematically showing the flow of current between the plate electrodes of the non-contact IC card shown in FIG. FIG. 8 is a circuit diagram showing an equivalent circuit of the non-contact IC card shown in FIG. As shown in FIG. 6, the non-contact IC card 10a includes a film base 11, an IC chip 12, an antenna coil 13, first flat plate electrodes 14a and 14b, and a second flat plate electrode 16a, as in the first embodiment. 16b and a jumper wire 17 are provided.

  On the other hand, as shown in FIGS. 6A and 6B, the non-contact IC card 10a is different from the first embodiment in that the plate electrodes 14a, 14b, 16a, and 16b flow currents that flow through the antenna coil 13. A part of the coil pattern is formed so as to be on the road. Since the flat electrode 14a, 14b, 16a, 16b is included in the coil pattern including the antenna coil 13, for example, as shown in FIG. 7, a current flows across the film substrate 11 from the flat electrode 14b to the flat electrode 16b. . As described above, since the current flows along the traveling direction indicated by the illustrated arrow, in the region α, the amount of current flowing through the first plate electrode 14b is larger than the amount of current flowing through the second plate electrode 16b. In the region β, the amount of current flowing through the second plate electrode 16b is larger than the amount of current flowing through the first plate electrode 14b. The relationship between the current amounts is the same between the planar electrodes 14a and 16a. Further, instead of the current amount, an average current density in the electrode cross section on each of the plate electrodes 14a, 14b, 16a, and 16b may be used as an index. When the first and second flat plate electrodes 14a, 14b, 16a, and 16b are formed on the flow path flowing through the antenna coil 13 to constitute a part of the coil pattern, the flat plate electrodes 14a, 14b, 16a, and 16b are The antenna can be used as a part of the antenna, and the number of turns of the coil can be increased and the opening area of the antenna can be increased under a limited antenna formation region. An equivalent circuit diagram of such a non-contact IC card 10a is shown in FIG.

  Further, as shown in FIG. 7, the current flowing through the plate electrode 14b decreases from one end A toward the other end B, whereas the current flowing through the plate electrode 16b increases from one end A ′ toward the other end B ′. To do. For this reason, for example, as shown in FIG. 9A, the flat electrode 14b has a width-thick portion 14c, the other has a thin-width portion 14d, and the flat electrode 16b has a shape shown in FIG. As shown in b), one may be the thin portion 16c and the other may be the thick portion 16d. In this case, as shown in FIG. 9C, in the region α where the amount of current flowing through the first plate electrode 14b is larger than the amount of current flowing through the second plate electrode 16b, the first plate electrode 14b (14c) has a larger area than the second plate electrode 16b (16c), and the amount of current flowing through the second plate electrode 16b is larger than the amount of current flowing through the first plate electrode 14b. In the region β, the area of the second plate electrode 16b (16d) is larger than that of the first plate electrode 14b (14d). As described above, by reducing the plate electrode at a location where the amount of flowing current is small, it is possible to enlarge the formation region of other members such as the antenna coil 13 while keeping the current resistance low.

  The shape of the plate electrodes 14b and 16b is not limited to the above, and other shapes can be selected as appropriate. For example, as shown in FIGS. 10A and 10B, the planar shape may be triangular plate electrodes 14b and 16b. Also in this case, as shown in FIG. 10C, in the region α where the amount of current flowing through the first plate electrode 14b is larger than the amount of current flowing through the second plate electrode 16b, the first plate electrode In the region β, the area of 14b is larger than that of the second plate electrode 16b, and the amount of current flowing through the second plate electrode 16b is larger than the amount of current flowing through the first plate electrode 14b. The area of the second flat plate electrode 16b is larger than that of the first flat plate electrode 14b, and the formation region of other members such as the antenna coil 13 can be enlarged as described above.

  The contactless IC card according to the present embodiment has been described above, but the wireless communication medium with RFID according to the present invention is not limited to the above-described embodiment, and various modifications can be applied. For example, in the above-described embodiment, the film base material 11 is composed of a three-layer structure. However, the film base material 11 is not limited to a three-layer structure, and the film base material 11 is formed from a structure of four or more layers each made of dielectric. May be. In this case, the capacitance value of the capacitor constituted by the first and second plate electrodes 14a, 14b, 16a, 16b can be adjusted more finely. In the above embodiment, the first and second flat plate electrodes 14a, 14b, 16a, and 16b form two capacitors so that both ends of the antenna coil 13 are conductive. However, at least one of the capacitors is a capacitor. Any other configuration may be used, and the other electrode may be directly conducted.

  DESCRIPTION OF SYMBOLS 10, 10a ... Non-contact IC card (non-contact information medium), 11 ... Film base material, 11c ... Intermediate base material, 11d ... 1st adjustment dielectric layer, 11e ... 2nd adjustment dielectric layer, DESCRIPTION OF SYMBOLS 12 ... IC chip, 13 ... Antenna coil, 14a, 14b ... 1st flat plate electrode, 16a, 16b ... 2nd flat plate electrode, 17 ... Jumper wire.

Claims (8)

A film substrate made of a dielectric;
An antenna coil disposed on at least one surface of the film substrate;
An IC chip that performs wireless communication processing via the antenna coil;
A first flat plate electrode connected to the antenna coil and disposed on the one surface of the film substrate;
A second flat plate electrode disposed on the other surface of the film base so as to face the first flat plate electrode in the thickness direction across the film base;
With
The film substrate includes an intermediate substrate made of a dielectric, a first adjustment dielectric layer made of a dielectric and formed on one surface of the intermediate substrate, and a dielectric made of the intermediate substrate. A second adjustment dielectric layer formed on the other surface,
The non-contact type information medium, wherein a dielectric constant of a dielectric constituting the first and second adjustment dielectric layers is equal to or greater than a dielectric constant of a dielectric constituting the intermediate base material. The non-contact type information medium according to claim 1, wherein the first and second adjustment dielectric layers are thinner than the intermediate substrate. The non-contact type information medium according to claim 1 or 2, wherein a dielectric material constituting the first and second adjustment dielectric layers is different from a dielectric material constituting the intermediate substrate. The thickness of the metal foil that constitutes the antenna coil is thicker than the thickness of the metal foil constituting the second plate electrode, the non-contact type information medium according to any one of claims 1-3. The area of the second plate electrode in the plane direction is larger than the area of the first plate electrode in the plane direction;
When viewed from a direction orthogonal to the plane direction of the first and second plate electrodes, the first plate electrode is included within the second plate electrodes, any claim 1-4 A non-contact type information medium according to claim 1. The area in the plane direction of the first plate electrode is larger than the area in the plane direction of the second plate electrode,
When viewed from a direction orthogonal to the plane direction of the first and second plate electrodes, the second plate electrode is included within the first plate electrode, any claim 1-4 A non-contact type information medium according to claim 1. The first and second flat plate electrodes are formed on a flow path of a current flowing through the antenna coil to form a part of a coil pattern, and the second flat plate is larger than the amount of current flowing through the first flat plate electrode. In a region where the amount of current flowing through the electrode is larger, the second flat plate electrode is formed to have a larger area than the first flat plate electrode, and flows through the second flat plate electrode. In a region where the amount of current flowing through the first plate electrode is larger than the amount of current, the first plate electrode is formed to have a larger area than the second plate electrode. The non-contact type information medium according to any one of claims 1 to 4 . The first and second plate electrodes are formed on a flow path of a current flowing through the antenna coil to form a part of a coil pattern, and are more than an average current density in an electrode cross section on the first plate electrode. In the region where the average current density in the electrode cross section on the second plate electrode is larger, the second plate electrode is formed to have a larger area than the first plate electrode. In the region where the average current density in the electrode cross section on the first plate electrode is larger than the average current density in the electrode cross section on the second plate electrode, the first plate electrode There than said second plate electrodes are formed so that the area becomes larger, non-contact type information medium according to any one of claims 1-4.

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