IC card

Abstract

To provide an IC card that improves communication performance by optimizing antenna design.SOLUTION: An IC card 1 according to the present invention includes: a card base material 5 having an opening 51; an antenna board 10 including an insulating antenna sheet 11 provided on the back surface side of the card base material 5, a conductive antenna coil formed on the back surface of the antenna sheet 11, and a conductive first coupling coil 122 formed on the surface of the antenna sheet 11 and at least partially exposed from the opening; and an IC module 20 including a substrate 21 fitted into the opening 51 of the card base material 5 and formed into a sheet shape, and a connection coil formed spirally on the back surface of the substrate, facing the first coupling coil 122 in the thickness direction, and capable of electromagnetic coupling.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an IC card.

Background Art

[0002] As an IC card incorporating a semiconductor memory or the like, a so-called composite IC card (dual IC card) that functions as both a contact type and a non-contact type is known. The composite IC card is used, for example, for credit cards, cash cards, prepaid cards, membership cards, gift cards, transportation cards, passports, and driver's licenses. The composite IC card is equipped with, for example, contact terminals for contacting a contact type external device, an IC chip that functions as both a contact type and a non-contact type, an IC module in which a coil is formed, and a coupling coil for electrically coupling non-contactingly to the coil formed in the IC module, and an antenna sheet having a communication antenna coil (main coil) for non-contact communication with an external terminal, and is configured by sandwiching the antenna sheet with an exterior base material. As the exterior base material, a sheet mainly made of polyvinyl chloride (PVC), vinyl chloride or vinyl acetate copolymer is used.

[0003] Due to the diversification of recent customer demands, there is an increasing need for IC cards that differentiate themselves from general cards by applying metal to the surface of the exterior base material or using a metal plate for the exterior base material to produce a metallic feeling visually and in terms of design to have a unique high-class feeling. For such a non-contact communication IC card using metal for the exterior base material, a through hole for accommodating an IC module is provided in the metal plate that is the exterior base material to electrically connect the IC module and the coupling coil (see, for example, Patent Document 1).

[0004] On the other hand, in order to reduce the manufacturing cost of IC cards, in recent years, the contact terminals have been changed from the conventional eight island-shaped contact terminals to six island-shaped contact terminals, and miniaturized IC chips are widely used.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2015 / 0235122 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, IC cards like the one described in Patent Document 1 have a problem in that their communication characteristics deteriorate because they are formed by laminating a metal outer substrate onto an antenna sheet equipped with an antenna. Furthermore, when the number of terminals on an IC card is reduced from eight to six compared to conventional contact terminals, the communication performance deteriorates even further.

[0007] This invention was made in consideration of these circumstances, and aims to provide an IC card that optimizes antenna design to improve communication performance. [Means for solving the problem]

[0008] To solve the above problems, this invention proposes the following means. An IC card according to a first aspect of the present invention comprises: a card substrate having an opening; an antenna substrate having an insulating antenna sheet provided on the back side of the card substrate; a conductive antenna coil formed on the back side of the antenna sheet; and a conductive first coupling coil formed on the surface of the antenna sheet, with at least a portion of it exposed from the opening; and an IC module having a substrate fitted into the opening of the card substrate and formed in the shape of a sheet; and a connecting coil formed spirally on the back side of the substrate, facing the first coupling coil in the thickness direction and capable of electromagnetic coupling. [Effects of the Invention]

[0009] The IC card according to the present invention provides an IC card that optimizes antenna design and improves communication performance. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic plan view showing an IC card according to one embodiment of the present invention. [Figure 2] This is a perspective view illustrating the configuration of the IC card. [Figure 3] This is a schematic side view showing the IC card along the AA cross-section in Figure 1. [Figure 4] This is a schematic plan view showing the card base material of the IC card. [Figure 5] This is a schematic plan view showing the antenna board of the IC card. [Figure 6] This is a perspective view illustrating the configuration of the antenna board of the IC card. [Figure 7] Figure 5 is a magnified view of the coupling coil on the antenna board of the same IC card. [Figure 8] Figure 5 shows the coupling coil of the antenna substrate of the IC card, viewed from above in the thickness direction. [Figure 9] (a) is a perspective view of the IC module of the IC card, seen from the front side. (b) is a perspective view of the IC module of the IC card, seen from the back side. [Figure 10] This figure shows the measurement results of the communication performance of the IC module of this IC card compared to a conventional IC card. [Figure 11] This figure illustrates another variation of the antenna substrate for the IC card of the present invention. [Modes for carrying out the invention]

[0011] (One embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 to 10. In the embodiments and modifications described below, the same reference numerals are assigned to corresponding configurations, and the description of overlapping portions may be omitted. Further, in the following description, expressions indicating relative or absolute arrangements such as "parallel", "orthogonal", "center", "coaxial", etc. not only strictly represent such arrangements, but also represent a state of being relatively displaced with tolerances and angles or distances that can obtain the same function.

[0012] FIG. 1 is a plan view schematically showing an IC card 1 according to an embodiment of the present invention. FIG. 2 is a perspective view for explaining the configuration of the IC card 1 in FIG. 1. FIG. 3 is a side view schematically showing the same IC card 1 along the A-A cross section in FIG. 1.

[0013] In the following description of the IC card 1, the direction along the long side of the IC card 1 is defined as the long side direction D1, and the direction along the short side of the IC card 1 orthogonal to the long side direction D1 on the horizontal plane is defined as the short side direction D2. The surfaces along the long side direction D1 and the short side direction D2 are horizontal planes (hereinafter simply referred to as horizontal planes). Further, the vertical direction orthogonal to the long side direction D1 and the short side direction D2 is defined as the plate thickness direction Dt.

[0014] In the long side direction D1, one side away from the central axis (not shown) along the plate thickness direction Dt of the IC card 1 is defined as the left side LH, and the other side is defined as the right side RH. In the short side direction D2, one side is defined as the front side FR, and the other side is defined as the rear side RR. Further, in the plate thickness direction Dt of the IC card 1, the upper side is defined as the upper side UP, and the lower side is defined as the lower side DW. The surface provided on the upper side UP side of the plate thickness direction Dt is defined as the front surface, and the surface provided on the lower side DW is defined as the back surface.

[0015] As shown in FIG. 1, the IC card 1 is a dual IC card that enables both contact-type communication and non-contact-type communication with external devices. In this embodiment, the communication area for non-contact-type communication uses the HF band (13.56 MHz) that is generally distributed in the market. The IC card 1 is plate-shaped and is formed in a rectangular shape having long sides and short sides that oppose each other when viewed from the upper side UP in the plate thickness direction Dt. The thickness of the IC card 1 in the plate thickness direction Dt is formed to be about 0.5 to 1.0 mm, for example. (When the IC card 1 is a credit card, the thickness of the IC card 1 is 0.76 mm).

[0016] The IC card 1 includes a card base material 5, an antenna substrate 10, an IC module 20, and an adhesive layer 40.

[0017] [Card base material 5] FIG. 4 is a plan view schematically showing the card base material 5 of the IC card 1. As shown in FIG. 2 or FIG. 3, the card base material 5 is a base material disposed on the surface 1f side of the IC card 1. The surface 5f of the card base material 5 is the surface 1f of the IC card 1. The thickness t1 of the card base material 5 in the plate thickness direction Dt is larger than the thickness t2 of the IC module 20 to be described later in the plate thickness direction Dt, for example, as shown in FIG. 3. In this embodiment, the card base material 5 is formed of metal, and materials such as iron, stainless steel, copper, nickel, tin, zinc iron, aluminum, magnesium, chromium, cobalt, molybdenum, titanium, and alloys thereof can be used. However, in order to further pursue a sense of weight, it is desirable to use tungsten, which has a large specific gravity, is inexpensive compared to noble metals such as gold, and has low toxicity to the human body.

[0018] The material of the card base material 5 is not limited to metal. For example, the card base material 5 may be an insulating material that provides sufficient strength and embossability, such as a polyester material such as amorphous polyester, a vinyl chloride material such as PVC (polyvinyl chloride), a polycarbonate material, or PET-G (polyethylene terephthalate copolymer), which provides the necessary properties for a card. The card base material 5 may also be formed using a metal sheet or a magnetic material. Furthermore, the card base material 5 may be molded into a card shape using a plastic material with high fluidity and insulating properties, such as a UV-curing type or a mixed-liquid reaction-curing type.

[0019] The shape of the card substrate 5, including its external form, can be appropriately adapted to the card standard. The card substrate 5 may be constructed as a laminate of two or more layers. The card substrate 5 may also have a magnetic layer, a protective layer, etc., or may have a functional surface coating such as thermal, thermal transfer, or inkjet. The surface 5f of the card substrate 5 preferably has light transmission, colored transparency, or colorless transparency. The card substrate 5 may also have fine linear protrusions or recesses formed on it. The card substrate 5 has an opening 51.

[0020] As shown in Figure 3, the opening 51 penetrates the card substrate 5 in the thickness direction Dt. The opening 51 is formed, for example, by milling the card substrate 5. The shape of the opening 51 as viewed from the upper side UP of the card substrate 5, which is the surface 5f of the card substrate 5, is not particularly limited, but in this embodiment, as shown in Figure 1, it is formed in a substantially rectangular shape to match the module substrate 21 of the IC module 20 described later. In addition, as shown in Figure 3, the opening 51 has a small gap C between the inner circumferential surface of the opening 51 and the IC module 20. By providing a gap C, it is possible to eliminate the risk of the module substrate 21 coming into contact with the card substrate 5, which is made of a conductive metal, causing an electrical short circuit and resulting in communication failure of the IC card.

[0021] [Antenna board 10] Figure 5 is a schematic plan view showing the antenna board 10 of the IC card 1. Figure 6 is a perspective view illustrating the configuration of the antenna board 10 of the same IC card. In this embodiment, the antenna substrate 10 is provided on the back surface 5g side of the card substrate 5, as shown in Figure 3. The back surface 10g of the antenna substrate 10 is the back surface 1g of the IC card 1. The antenna substrate 10 comprises an antenna sheet 11, a booster antenna 12, a front-to-back conductive portion 13, and a capacitor 14, as shown in Figure 5 or Figure 6.

[0022] The antenna sheet 11 is a flexible insulating substrate. The antenna sheet 11 can be made from materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), PET-G (terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer), polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polycarbonate, polyamide, polyimide, cellulose diacetate, cellulose triacetate, polystyrene-based materials, ABS, polyacrylic acid ester, polypropylene, polyethylene, polyurethane, polyimide, glass epoxy, and phenolic resin, as appropriate.

[0023] As shown in Figure 3, the booster antenna 12 is an antenna pattern provided on both the front surface 11f and the back surface 11g of the antenna sheet 11. The booster antenna 12 has a coupling coil 121 and a main coil (antenna coil) 124.

[0024] Figure 7 is an enlarged view of the coupling coil 121 of the antenna substrate 10 of the IC card 1 shown in Figure 5. Figure 8 is a view of the coupling coil 121 of the antenna substrate 10 of the IC card 1 shown in Figure 5, viewed from above (UP) in the thickness direction Dt. The coupling coil 121 comprises a conductive first coupling coil 122 and a conductive second coupling coil 123.

[0025] The first coupling coil 122 is formed in a spiral shape, with two or more turns on the surface 11f of the antenna sheet 11 to form a rectangle, as shown in Figure 7 or Figure 8. At least a portion of the first coupling coil 122 is exposed from the opening 51 of the card base material 5. The first coupling coil 122 has a terminal portion 122p in the center of the inner circumference side 122i. The terminal portion 122p is wider than the wire width (thickness) of the first coupling coil 122 and is formed in a substantially circular shape. The first coupling coil 122 is also electrically connected to the first capacitor 141 of the capacitor 14 via connecting wiring (not shown).

[0026] The second coupling coil 123 is formed on the back surface 11g of the antenna sheet 11 in a rectangular shape, with two or more turns, as shown in Figure 7 or Figure 8, and is arranged in a spiral shape. The second coupling coil 123 has a terminal portion 123p in the center of the inner circumference side 123i. The terminal portion 123p is wider than the wire width (thickness) of the second coupling coil 123 and is formed in a substantially circular shape. The second coupling coil 123 is electrically connected to the second capacitor 142 of the capacitor 14 via connecting wiring (not shown).

[0027] The second coupling coil 123 has a wider wire width (thickness) than the first coupling coil 122. Therefore, the thickness of the second coupling coil 123 in the plate thickness direction Dt is formed to be greater than the thickness of the first coupling coil 122. Also, as shown in Figure 8, the second coupling coil 123 is formed to overlap the first coupling coil 122 when viewed from the plate thickness direction Dt. Note that the configuration of the second coupling coil 123 is not essential. The booster antenna 12 does not need to have a second coupling coil 123.

[0028] As shown in Figure 3, the opening 51 of the card substrate 5, the first coupling coil 122, the antenna sheet 11, and the second coupling coil 123 are arranged in this order from the upper side UP to the lower side DW along the thickness direction Dt. Furthermore, the first coupling coil 122 and the second coupling coil 123 are approximately the same size and shape as the opening 51 of the card substrate 5 when viewed from the surface 5f of the card substrate 5. Specifically, as shown in Figure 8, the outermost conductor 122a of the first coupling coil 122, which is spirally formed from the central terminal portion 122p, is formed so as to be slightly inward from the periphery 510 of the opening 51 when viewed from the surface 5f side of the card substrate 5, or overlapping with the periphery 510. Similarly, the outermost conductor 123a of the second coupling coil 123, which is spirally formed from the central terminal portion 123p, is formed so as to be slightly inward from the periphery 510 of the opening 51 when viewed from the surface 5f side of the card substrate 5, or overlapping with the periphery 510. Furthermore, as shown in Figure 8, the conductors of the first coupling coil 122 and the conductors of the second coupling coil 123 are arranged to overlap substantially when viewed from the plate thickness direction Dt, and a gap is formed between the conductors.

[0029] The main coil (antenna coil) 124 is provided on the back surface 11g of the antenna sheet 11, as shown in Figure 6. The main coil 124 is electrically connected to the second coupling coil 123 and the second capacitor 142 on the back surface 11g of the antenna sheet 11 by wiring (not shown), enabling contactless communication with contactless external devices such as a reader / writer. The main coil 124 is formed in a rectangular shape along the periphery 11k of the antenna sheet 11, as shown in Figure 5. The main coil 124 is formed with one or two turns along the periphery 11k of the antenna sheet 11, as shown in Figure 2. However, the main coil 124 only needs to be capable of contactless communication with contactless external devices, and the number of turns, shape, and wire width are not limited.

[0030] The wire width of the main coil 124 is wider than that of the coupling coil 121. The wire widths of the coupling coil 121 and the main coil 124 can be set as appropriate, and it is preferable to set them so that their imaginary impedances are equal at the set communication frequency. However, the wire width of the main coil 124 may be approximately the same as that of the coupling coil 121, or it may be narrower than that of the coupling coil 121.

[0031] There are no particular limitations on the manufacturing method of the booster antenna 12, which includes a coupling coil 121 and a main coil 124, and it can be formed by various methods. Examples of manufacturing methods include laser cutting or punching of metal plates or metal foils, etching of metal foils or metal layers, and arrangement of metal wires. Punching is particularly suitable when forming a wide main coil 124. If the coupling coil 121 is formed using insulated metal wire, it is not necessary to place a separate insulator at the three-dimensional intersection, and it can be formed simply. When the coupling coil 121 and the main coil 124 are formed from different materials, soldering, welding, or pressure welding can be used as methods for connecting them. The width (thickness), spacing, and number of turns of the booster antenna 12 can be appropriately set according to the characteristics of the booster antenna 12 and constraints imposed by its arrangement.

[0032] The front-back conductive portion (conductive portion) 13 provides electrical conductivity between the inner circumference side 122i of the first coupling coil 122, which is provided on the front surface 11f of the antenna sheet 11, and the inner circumference side 123i of the second coupling coil 123, which is provided on the back surface 11g, thereby connecting the first coupling coil 122 and the second coupling coil 123.

[0033] Specifically, the front-to-back conductive portion 13 is formed on the antenna substrate 10 by crimping a terminal portion 122p, which is located in the center of the inner circumference 122i of the first coupling coil 122 toward the lower side DW of the thickness direction Dt, and a terminal portion 123p, which is located in the center of the inner circumference 123i of the second coupling coil 123. As shown in Figure 3, the front-to-back conductive portion 13 has a first protrusion (projection) 130 that protrudes from the terminal portion 122p of the first coupling coil 122 toward the back surface 10g of the antenna substrate 10. The front-to-back conductive portion 13 also has a second protrusion (projection) 131 that protrudes from the terminal portion 123p of the second coupling coil 123 toward the back surface 10g of the antenna substrate 10.

[0034] The first protrusion 130 and the second protrusion 131 are electrically connected by crimping. This configuration allows the antenna patterns on both the front surface 11f and the back surface 11g of the booster antenna 12 provided on the antenna sheet 11 to be electrically connected. The method for electrically connecting the antenna patterns on both the front surface 11f and the back surface 11g of the booster antenna 12 is not particularly limited. For example, after forming the antenna patterns on both the front surface 11f and the back surface 11g of the booster antenna 12, holes for electrical connection may be formed at desired positions and then filled with conductive ink to create electrical connection, or electrical connection may be achieved by plating.

[0035] Capacitor 14 is, for example, a chip capacitor (including a flat plate capacitor). Capacitor 14 forms a resonant circuit with the main coil 124 and adjusts the resonant frequency. Capacitor 14 comprises a first capacitor 141 and a second capacitor 142.

[0036] The first capacitor 141 is provided on the surface 11f of the antenna sheet 11. The first capacitor 141 is connected in series or parallel to the first coupling coil 122.

[0037] The second capacitor 142 is located on the back surface 11g of the antenna sheet 11. It is connected in series or parallel to the second coupling coil 123 and the main coil 124, and is formed to overlap the first capacitor 141 when viewed from the plate thickness direction Dt.

[0038] The capacitance of capacitor 14 can be changed by altering the overlapping area between the first capacitor 141 and the second capacitor 142. Capacitor 14's capacitance can be adjusted by changing the line width, length, and relative arrangement of the electrodes of both the first capacitor 141 and the second capacitor 142. One way to change the overlapping area is to set the length, line width, and relative arrangement of the electrodes when they are formed. Alternatively, the capacitance of the capacitor can be changed by forming electrodes of a certain length, line width, and relative arrangement, and then removing the electrodes to shorten or narrow their length and line width. Capacitor 14 can be formed by etching copper foil or aluminum foil coated with resist using general gravure printing.

[0039] [IC Module 20] Figure 9(a) is a perspective view of the IC module 20 of IC card 1, viewed from the front surface 20f side. Figure 9(b) is a perspective view of the IC module 20 of IC card 1, viewed from the back surface 20g side. The IC module 20 is fitted into the opening 51 of the card substrate 5. As shown in Figures 9(a) and (b), the IC module 20 comprises a module substrate (substrate) 21, an IC chip 22, a connecting coil 23, contact terminals 24, and a resin sealing portion 30. The external dimensions of the IC module 20 are approximately 8 mm × 10.6 mm in the horizontal plane, for example, if the contact terminals 24 consist of 6 terminals. In this embodiment, the IC module 20 is positioned to the left LH in the long side direction D1 and forward FR in the short side direction D2 from the central axis (not shown) of the IC card 1.

[0040] As shown in Figure 3, the thickness t2 of the IC module 20 in the thickness direction Dt is smaller than the thickness t1 of the card base material 5 in the thickness direction Dt. Furthermore, the IC module 20 is positioned with a small gap C between it and the inner surface of the opening 51 to prevent it from contacting the inner surface of the opening 51 and causing an electrical short circuit.

[0041] The module substrate (substrate) 21 is a sheet-like substrate formed on a horizontal surface using a material such as glass epoxy or PET. The module substrate 21 has a surface 21f and a back surface 21g in the thickness direction Dt, and is formed in a rectangular shape when viewed from the thickness direction Dt.

[0042] As shown in Figure 9(b), the IC chip 22 is mounted on the back surface 21g of the module substrate 21. The IC chip 22 can be of a known configuration having contact-type communication function and contactless communication function. The IC chip 22 mounted on the back surface 21g of the module substrate 21 has a plurality of terminals (not shown) and is electrically connected to the electrodes of the connection coil 23 (described later) and the contact terminal 24 mounted on the front surface 21f via wiring, wires, through-holes or vias formed by copper plating, etc., formed on the module substrate 21. The IC chip 22 is formed in a rectangular shape when viewed from the thickness direction Dt, for example. The IC chip 22 is also positioned on the inner circumference side 23i of the connection coil 23.

[0043] The connecting coil 23 is attached to the back surface 21g of the module substrate 21 using an adhesive (not shown). The connecting coil 23 is formed by winding it spirally about a dozen times so that the IC chip 22 is positioned on the inner circumference side 23i. The connecting coil 23 is formed, for example, by etching a pattern of copper foil or aluminum foil onto the back surface 21g of the module substrate 21, and the thickness of the connecting coil 23 is 5 to 50 μm. At the outermost and innermost ends of the connecting coil 23, outermost terminal portions 231 and innermost terminal portions 232 are formed, which are wider than the wire width (thickness) of the connecting coil 23. The outermost terminal portions 231 and innermost terminal portions 232 are provided with through holes or vias and are electrically connected to some of the multiple electrodes provided on the IC chip 22 by wire bonding or the like.

[0044] The connecting coil 23 is positioned so as to be able to electromagnetically couple with the coupling coil 121 of the booster antenna 12 when the IC module 20 is fitted into the opening 51 of the card base material 5 from the surface 10f side of the antenna substrate 10. The connecting coil 23, the opening 51 of the card base material 5, the first coupling coil 122, the antenna sheet 11, and the second coupling coil 123 are arranged in this order from the upper side UP to the lower side DW along the thickness direction Dt of the board.

[0045] The contact terminal 24 is configured to be able to contact an external contact-type device (not shown). The contact terminal 24 is formed on the surface 21f of the module substrate 21, as shown in Figure 3 or Figure 9(a). The contact terminal 24 is composed of, for example, six terminals. The contact terminal 24 has electrodes (not shown) on its back surface. The contact terminal 24 is electrically connected to the IC chip 22 via through-holes or vias formed by wiring, wires, copper plating, etc., formed on the module substrate 21. Note that the contact terminal does not have to be six terminals; it may be a conventional eight terminal configuration.

[0046] The resin encapsulation portion 30 is a protruding portion that covers the wiring and wires formed on the back surface 21g of the module substrate 21 and the IC chip 22. As shown in Figure 3, the resin encapsulation portion 30 is provided on the back surface 21g of the module substrate 21. The resin encapsulation portion 30 overlaps with the front-back conductive portion 13 in the thickness direction Dt. The resin encapsulation portion 30 can be formed from, for example, a known epoxy resin, an ultraviolet curable resin, or a thermosetting resin. The resin encapsulation portion 30 can protect the IC chip 22 from external forces and environmental loads, and prevent wire breakage. The resin encapsulation portion 30 is generally positioned with its center aligned with the IC chip 22.

[0047] [Adhesive layer 40] As shown in Figure 3, the adhesive layer 40 adheres the card substrate 5 and the antenna substrate 10. The adhesive layer 40 is an insulator formed by applying an adhesive or laminating adhesive sheets. The adhesive layer 40 is composed of materials such as polyvinyl acetate resin, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, acrylic resin, polyester resin, polyamide resin, polyurethane resin, and nitrocellulose. The adhesive layer 40 has an adhesive layer opening 401 that penetrates the adhesive layer 40. The adhesive layer opening 401 is formed to have the same shape and size as the opening 51 of the card substrate 5 when viewed from the plate thickness direction Dt.

[0048] IC card 1 is formed by sandwiching an antenna substrate 10, a card base material 5 and adhesive layer 40 laminated on the antenna substrate 10, and an IC module 20 fitted into an opening 51 in the card base material 5, between them using heat-pressure lamination or adhesive, and then punching out the shape of a card. IC card 1 may be further embossed or otherwise processed after molding.

[0049] (action) Next, the operation of IC card 1 will be explained using Figure 10. Figure 10 is a graph showing the measurement results of the communication performance of IC module 20 of IC card 1 compared with a conventional IC card. In the graph of Figure 10, the horizontal axis shows frequency and the vertical axis shows communication performance (gain).

[0050] Generally, the higher the communication performance of the IC module 20, the higher the overall communication performance of the IC card 1. In this embodiment, the higher the measurement result is, the higher the communication performance of the IC module 20. In the graph of Figure 10, Example 1, shown by a solid line, is the measurement result of the communication performance of the IC module 20 of the IC card 1 according to one embodiment of the present invention. Also in the graph of Figure 10, Comparative Example 1, shown by a dotted line, is the measurement result of the communication performance of the IC module of a conventional IC card. The conventional IC card has 8 contact terminals on the IC module compared to the IC card 1 according to one embodiment of the present invention. In addition, the conventional IC card has a coupling coil of a booster antenna provided on the antenna substrate that is spirally arranged to draw a circle larger than the opening of the card substrate.

[0051] As shown in Figure 10, the measurement results of the IC module 20 in Example 1 show that the communication performance is higher than that of Comparative Example 1 at all frequencies. Therefore, it can be confirmed that the communication performance of the IC card 1 according to one embodiment of the present invention, Example 1, is higher than that of the IC card in Conventional Example 1.

[0052] In this embodiment, the first coupling coil 122, at least a portion of which is exposed through the opening 51 of the card substrate 5, and the connecting coil 23 of the IC module 20 fitted into the opening 51, are able to be electromagnetically coupled facing each other. By providing the opening 51 in the card substrate 5 of the IC card 1, interference between the first coupling coil 122 and the connecting coil 23 can be eliminated, thereby achieving high communication performance.

[0053] Furthermore, in this embodiment, the card base material 5 is made of metal. Therefore, the IC card 1 can have high communication performance while differentiating itself from ordinary cards, and can have a sense of weight and a unique sense of luxury.

[0054] Furthermore, in this embodiment, a second coupling coil 123 is provided on the back surface 11g of the antenna sheet 11. This configuration increases the degree of freedom in designing the number of turns and arrangement of the coupling coil 121 as a whole. Moreover, the first coupling coil 122 and the second coupling coil 123 are approximately the same size and shape as the opening 51 of the card substrate 5 when viewed from the plate thickness direction Dt. Therefore, the efficiency of magnetic field coupling between the coupling coil 121 and the IC module 20 can be optimized, and communication performance can be further improved.

[0055] Furthermore, in this embodiment, the thickness of the second coupling coil 123 in the plate thickness direction Dt is greater than the thickness of the first coupling coil 122. Therefore, the IC card 1 reduces the influence (reduction in inductance) that the first coupling coil 122, which is closer to the card substrate 5, receives from the metal constituting the card substrate 5, while increasing the thickness of the second coupling coil 123, which is further away from the card substrate 5. This reduces the conductor resistance and lowers the overall resistance of the coupling coil 121, thereby further improving communication performance.

[0056] Furthermore, in this embodiment, the conductors of the first coupling coil 122 and the second coupling coil 123 substantially overlap when viewed from the plate thickness direction Dt. Therefore, a misalignment occurs in the antenna patterns on the front surface 10f and back surface 10g of the antenna substrate 10, preventing the gap between the two coils from disappearing when viewed from the plate thickness direction Dt. This prevents the communication performance of the IC card 1 from degrading due to the magnetic flux becoming difficult to pass through if the gap between the coils disappears. Moreover, in this embodiment, it is possible to increase the stray capacitance between the first coupling coil 122 and the second coupling coil 123, thereby increasing the inductance of the coupling coil 121 as a whole, and increasing the coupling with the IC module 20.

[0057] Furthermore, in this embodiment, the front-to-back conductive portion 13 is provided with a first protrusion (protrusion) 130 and a second protrusion (protrusion) 131 that protrude towards the back surface 10g side by crimping a terminal portion 122p provided in the center of the inner circumference 122i of the first coupling coil 122 toward the lower side DW of the thickness direction Dt of the antenna substrate 10 to a terminal portion 122p provided in the center of the inner circumference 123i of the second coupling coil 123. With this configuration, the front-to-back conductive portion 13 can make the antenna patterns on both sides of the booster antenna 12 provided on the antenna sheet 11 electrically conductive, on the front surface 11f and the back surface 11g. In addition, since the first protrusion (protrusion) 130 and the second protrusion (protrusion) 131 protrude toward the back surface 10g side, they do not interfere with the resin sealing portion 30 provided on the back surface 21g of the module substrate 21 when the module substrate 21 is fitted into the opening 51. Furthermore, the resin sealing portion 30 provided on the back surface 21g of the module substrate 21 overlaps with the front-to-back conductive portion 13 in the thickness direction Dt. Therefore, the resin sealing portion 30 and the front-to-back conductive portion 13 do not interfere with each other, and the overall thickness of the IC card in the thickness direction Dt can be reduced.

[0058] Furthermore, in this embodiment, the number of contact terminals 24 is 6. Generally, reducing the number of contact terminals from 8 to 6 degrades the communication performance of the IC module. However, as can be seen from the measurement results shown in Figure 4, the 6-terminal contact terminal of Example 1 has higher communication performance than the 8-terminal IC module in the comparative example. Therefore, in this embodiment, an IC module 20 with high communication performance can be provided.

[0059] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment and includes design changes and the like that do not depart from the spirit of the present invention. Furthermore, the components shown in the above embodiment and the following modifications can be combined as appropriate.

[0060] (modified version) For example, in the embodiment described above, the first coupling coil 122 and the second coupling coil 123 are approximately the same size and shape as the opening 51 of the card substrate 5 when viewed from the plate thickness direction Dt, but are not particularly limited. The first coupling coil 122 and the second coupling coil 123 may be housed inside the periphery 510 of the opening 51 when viewed from the plate thickness direction Dt. Even in this case, the IC card of the present invention can optimize the efficiency of magnetic field coupling between the coupling coils and the IC module, and further improve communication performance.

[0061] Furthermore, the first coupling coil and the second coupling coil of the booster antenna provided on the antenna substrate of the present invention may be formed to be one turn larger than the edge of the opening when viewed from the surface side of the card substrate. In this case as well, the IC card of the present invention can increase the number of turns of the coupling coil and improve communication characteristics.

[0062] Furthermore, the number of turns of the second coupling coil of the booster antenna provided on the antenna substrate of the present invention may be formed to be greater than the number of turns of the first coupling coil. Specifically, for example, as shown in Figure 11, the second coupling coil 123A of the coupling coil 121A has one more turn than the first coupling coil 122 compared to the embodiment described above. That is, the outermost conductor 123Aa of the second coupling coil 123A is positioned outside the peripheral edge 510 of the opening 51 and is covered by the card substrate 5 when viewed from the surface 5f of the card substrate 5, which is on the upper side UP of the plate thickness direction Dt. Also, the outermost conductor 123Aa of the second coupling coil 123A is positioned on the outer circumference side opposite to the inner circumference side 122i of the first coupling coil 122, compared to the outermost conductor 122a of the first coupling coil 122. In this case as well, the first coupling coil 122, which is closer to the card substrate 5, can be less affected by the metal constituting the card substrate 5 (reduction in inductance), while the number of turns of the second coupling coil 123A, which is further away from the card substrate 5, can be increased. This reduces the conductor resistance, lowers the overall resistance of the coupling coil 121A, and further improves communication performance.

[0063] Furthermore, while the embodiments described above described an example of a so-called hybrid IC card that functions as both a contact-type and a contactless-type IC card, the invention is not particularly limited and can also be applied to IC cards that function only as a contact-type or IC cards that function only as a contactless-type.

[0064] In any of the above embodiments, the IC card according to the present invention can provide an IC card that optimizes the antenna design and improves communication performance. [Industrial applicability]

[0065] The IC card according to the present invention is industrially applicable because it optimizes the antenna design to improve communication performance. [Explanation of symbols]

[0066] 1 IC card 1f surface 1g (back side) 5 card base materials 51 Opening 510 Periphery 10 Antenna board 10f surface 10g back side 11 Antenna sheet 12 Booster Antenna 13. Conductive parts on both sides (conductive parts) 130 First protrusion (protrusion) 131 Second protrusion (protrusion) 121 Coupling coil 122 First coupling coil 122a (Outermost wire of the first coupling coil) 122i (Inner side of the first coupling coil) 122p (Terminal section of the first coupling coil) 123 Second coupling coil 123a (Outermost wire of the second coupling coil) 123i (Inner side of the second coupling coil) 123p (Terminal section of the third coupling coil) 124 Main coil (antenna coil) 14 Capacitors 20 IC modules 21 Module board (board) 21f surface 21g back side 22 IC chips 23 Connecting coil 23i Inner side 24 Contact terminal 30 Resin sealing part 40 Adhesive 30 Resin sealing part D1 Long side direction D2 Short side direction Dt Thickness direction

Claims

1. A card base material having an opening, An antenna substrate having an insulating antenna sheet provided on the back side of the card substrate, a conductive antenna coil formed on the back side of the antenna sheet, and a conductive first coupling coil formed on the surface of the antenna sheet, with at least a portion of it exposed from the opening, An IC module having a substrate formed in a sheet shape and fitted into the opening of the card substrate, and a connecting coil formed spirally on the back surface of the substrate, facing the first coupling coil in the thickness direction and capable of electromagnetic coupling, Equipped with IC card.

2. The card base material is formed of metal. The IC card according to claim 1.

3. The antenna substrate is formed on the back surface of the antenna sheet and further has a conductive second coupling coil that overlaps with the first coupling coil in the thickness direction of the antenna sheet. The first coupling coil and the second coupling coil are substantially the same size and shape as the opening of the card substrate when viewed from the thickness direction of the plate. The IC card according to claim 1 or claim 2.

4. The antenna substrate is formed on the back surface of the antenna sheet and further has a conductive second coupling coil that overlaps with the first coupling coil in the thickness direction of the antenna sheet. The first coupling coil and the second coupling coil are positioned inside the edge of the opening when viewed from the plate thickness direction. The IC card according to claim 1 or claim 2.

5. The antenna substrate further comprises two or more windings formed on the back surface of the antenna sheet, and a conductive second coupling coil that overlaps with the first coupling coil in the thickness direction of the antenna sheet. The first coupling coil is formed with two or more turns, The first coupling coil and the second coupling coil are each one turn larger than the edge of the opening when viewed in the plate thickness direction. The IC card according to claim 1 or claim 2.

6. The antenna substrate is formed on the back surface of the antenna sheet and has a conductive second coupling coil that overlaps with the first coupling coil in the thickness direction of the antenna sheet. The thickness of the second coupling coil in the thickness direction is greater than the thickness of the first coupling coil. The IC card according to claim 1 or claim 2.

7. The antenna substrate has two or more windings formed on the back surface of the antenna sheet, and has a conductive second coupling coil that overlaps with the first coupling coil in the thickness direction of the antenna sheet. The number of turns in the second coupling coil is greater than the number of turns in the first coupling coil. The IC card according to claim 1 or claim 2.

8. The antenna substrate is formed on the back surface of the antenna sheet and has a conductive second coupling coil that overlaps with the first coupling coil in the thickness direction of the antenna sheet. The conductors of the first coupling coil and the conductors of the second coupling coil overlap substantially when viewed from the direction of the plate thickness. The IC card according to claim 1 or claim 2.

9. The antenna substrate further comprises a conductive second coupling coil formed on the back surface of the antenna sheet and overlapping the first coupling coil in the thickness direction of the antenna sheet, and conductive portions on the inner circumference side of the first coupling coil and the inner circumference side of the second coupling coil that connect the first coupling coil and the second coupling coil electrically. The IC card according to claim 1 or claim 2.

10. The conductive portion provides electrical conductivity between the first coupling coil and the second coupling coil at the central portion of the first coupling coil and the central portion of the first coupling coil. The IC card according to claim 9.

11. The IC module further comprises an IC chip having a contact communication function on the back surface of the substrate, and a resin sealing portion covering the IC chip and provided on the back surface of the substrate. The IC card according to claim 9.

12. The resin sealing portion overlaps with the conductive portion in the thickness direction of the plate. The IC card according to claim 11.

13. The conductive portion is formed by crimping and has a protrusion that extends outwards from the back side of the antenna substrate. The IC card according to claim 12.

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