JP7806590B2 - Dual interface IC card and its manufacturing method - Google Patents

Description

The present invention relates to a dual-interface IC card capable of contact and contactless communication with external devices.

Conventionally, IC cards include contact IC cards that input and output electrical signals through an external connection terminal on the surface of the card, and contactless IC cards that input and output electrical signals via an antenna using electromagnetic induction or other methods. In addition to these, dual interface IC cards, which combine contact and contactless functions with a single IC chip, are also in use. Dual interface IC cards, in particular, can be used as contact IC cards, which are effective in preventing external leakage of input and output data during financial transactions, and as highly convenient contactless IC cards that exchange data in close proximity when entering and exiting a room or at a ticket gate at a station. For this reason, dual interface IC cards are becoming increasingly popular in the market.

Dual interface IC cards are manufactured as follows. First, as described in Patent Document 1, a card substrate containing one or more core sheets is formed, and an area for embedding an IC module is cut from the surface of the card substrate. The IC module is then embedded in the area. Conductive wires are arranged on one of the one or more core sheets, and the conductive wires form a wound antenna section for providing the contactless communication function and contact terminal sections that are in electrical contact with the terminals of the IC module. The contact terminal sections are, for example, arranged in a meander shape.

The intended embedding area is cut to include the first recess, the second recess, and the contact opening in the first recess. The first recess is for accommodating the substrate portion of the IC module and is cut to a depth that does not expose the contact terminal portion of the conductor wire present inside the card substrate. The second recess is for accommodating the sealing portion of the IC module and is cut to a depth that does not expose the contact terminal portion of the conductor wire present inside the card substrate. Meanwhile, the contact opening in the first recess is cut deeper than the first recess until the contact terminal portion is exposed. By filling the contact opening with a conductive adhesive, the contact terminal portion and the terminal on the back side of the substrate portion of the IC module are electrically connected via the conductive adhesive. The IC module is fixed in the first recess in the intended embedding area by adhering adhesive tape to the back side of the substrate portion of the IC module.

Japanese Patent Application Laid-Open No. 2019-219732

To improve the efficiency of dual interface IC card manufacturing, it is desirable to use the same adhesive material for the electrical connection between the IC module and antenna and the mechanical connection between the IC module and card base. However, depending on the material and characteristics of the adhesive layer, the adhesive conditions required for achieving the electrical connection between the IC module and antenna often differ from the adhesive conditions required for achieving the mechanical connection between the IC module and card base. In particular, the distance between the adherends is thought to have a significant impact on adhesive strength. Furthermore, the recess for embedding the IC module is formed slightly larger than the IC module to accommodate mechanical errors in the device used to place the IC module. For this reason, depending on the type of adhesive layer, excess molten adhesive may spill out beyond the periphery of the IC module when the IC module is placed in the recess in the card base, resulting in poor appearance.

This disclosure was made in light of these circumstances, and aims to provide a dual interface IC card and a manufacturing method thereof that improves the reliability of both the electrical connection between the IC module and antenna and the mechanical connection between the IC module and card base, while also improving the appearance.

According to this embodiment, a dual interface IC card capable of contact and contactless communication with an external device comprises a card base with a recess, an antenna with an end portion disposed inside the card base, and an IC module having terminals electrically connected to an IC chip; the recess includes a first recess that includes a portion of the outer periphery of the recess and is separated from each other; a second recess that is adjacent to the first recess and separated from each other; and a third recess that is adjacent to the first recess and is formed closer to the center of the recess than the first and second recesses; the end portion of the second recess that faces the IC module is exposed from the card base toward the IC module; the IC module is disposed in the recess so that the terminals and the end portion are electrically connected; the first recess is formed deeper than the second recess, and the third recess is formed deeper than the first recess.

Furthermore, in a dual interface IC card according to another embodiment of the present invention, the end portion may be configured with an antenna wire that constitutes the antenna, with the antenna wire repeatedly folded back from the outer periphery of the recess toward the center.

In another embodiment of the dual interface IC card, the outer periphery may be a substantially rectangular shape with sides substantially parallel to the short and long sides of the card base, and the end portion may be configured with an antenna wire that forms the antenna, with the antenna wire repeatedly folding back from the outer periphery, which is a side of the recess substantially parallel to the short sides of the card base, toward the center.

Furthermore, in a dual interface IC card according to another embodiment of the present invention, a portion of the antenna other than the bent portion of the folded structure may be inclined with respect to a straight line along the outer periphery.

Furthermore, in a dual interface IC card according to another embodiment of the present invention, the end may be formed of a plate-shaped conductive member welded to the tip of the antenna wire that constitutes the antenna.

Furthermore, in a dual interface IC card according to another embodiment of the present invention, the terminals and ends of the IC module that face each other may be electrically connected via an anisotropic conductive film.

Furthermore, in a dual interface IC card according to another embodiment of the present invention, the anisotropic conductive film may be arranged so as to overlap the first recess and the second recess.

The method for manufacturing a dual interface IC card according to this embodiment includes the steps of preparing a first substrate, a second substrate, and an IC module having terminals electrically connected to an IC chip; forming an antenna having an end portion on one surface of the first substrate; laminating the first substrate and the second substrate by heat fusion or via an adhesive so as to sandwich the antenna to form a laminate; punching the laminate to card size to form a card base; forming a recess in the card base; and inserting the IC module into the terminals and the end portion. and placing the recess in the recess so that the terminals are electrically connected, the recess including a portion of the outer periphery of the recess and consisting of a first recess separated from each other, a second recess adjacent to the first recess and separated from each other, and a third recess adjacent to the first recess and formed closer to the center of the recess than the first and second recesses, the end of the second recess facing the IC module is exposed from the card base toward the IC module, the first recess is formed deeper than the second recess, and the third recess is formed deeper than the first recess.

This embodiment provides a dual interface IC card and a manufacturing method thereof that improves the reliability of both the electrical connection between the IC module and the antenna and the mechanical connection between the IC module and the card base, while also improving the appearance.

1 is a plan view illustrating the structure of a dual interface IC card according to a first embodiment. 2 is a cross-sectional view showing a cross section taken along line AA in FIG. FIG. 2 is a cross-sectional view showing a cross section taken along line BB in FIG. 1A and 1B are diagrams illustrating an IC module and a connection between the IC module and an antenna. FIG. 1B is a plan view corresponding to FIG. 1B, illustrating the structure of a dual interface IC card according to a second embodiment. FIG. 10 is a plan view corresponding to FIG. 1 and illustrating the structure of a dual interface IC card according to a third embodiment. 6(b) is a cross-sectional view taken along line DD in FIG. 6(b) and corresponds to FIG. 2. 6(b) is a cross-sectional view taken along line EE in FIG. 6(b) and corresponds to FIG. 3. FIG.

An example of a dual interface IC card according to the present disclosure will be described below with reference to the drawings, etc. However, the dual interface IC card according to the present disclosure is not limited to the embodiments and examples described below.

The figures shown below are schematic illustrations. Therefore, the size and shape of each part have been exaggerated as appropriate to make them easier to understand. Furthermore, hatching indicating the cross section of a component has been omitted as appropriate in each figure. The numerical values, such as dimensions, and material names of each component described in this specification are examples of an embodiment and are not limited to these, and may be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include substantially the same state in addition to their strict meaning.

1. First Embodiment An example of a first embodiment of a dual interface IC card according to the present disclosure will be described. Here, for ease of explanation, an XYZ coordinate system is set for the dual interface IC card 1. First, as shown in FIGS. 1( a) and 2(b), the Z axis is taken as the normal direction to the main surface of the dual interface IC card 1. The direction from the main surface on which the external connection terminals 71 of the IC module 70 are not arranged to the main surface on which the external connection terminals 71 are arranged is defined as the +Z direction or upward in the thickness direction, and the opposite direction is defined as the −Z direction or downward in the thickness direction.

When the dual interface IC card 1 is viewed from the +Z direction, the line perpendicular to both short sides of the dual interface IC card 1 and the Z axis is defined as the X axis. The direction from one short side closer to the external connection terminal 71 toward the other short side is defined as the +X direction or rightward direction, and the opposite direction is defined as the -X direction or leftward direction. The axis perpendicular to the X and Z axes is defined as the Y axis, and the direction from one long side farther from the external connection terminal 71 toward the other long side is defined as the +Y direction or upward direction, and the opposite direction is defined as the -Y direction or downward direction.

Here, Figure 1(a) is a plan view of the dual interface IC card 1 as viewed from the +Z direction, and Figure 1(b) is a diagram illustrating the arrangement of the antenna 80, enlarging the area near the external connection terminal 71 of the dual interface IC card 1 of Figure 1(a). However, to make the configuration of the antenna 80 easier to understand, the IC module 70 is removed. Meanwhile, Figure 2(a) is a cross-sectional view of the dual interface IC card 1 of Figure 1(b) taken along line A-A parallel to the X axis, as viewed from the -Y direction. Figure 2(a) is a diagram without the IC module 70, and Figure 2(b) is a diagram of Figure 2(a) with the IC module 70 installed. Furthermore, Figure 3(a) is a cross-sectional view of the dual interface IC card 1 of Figure 1(b) taken along line B-B parallel to the Y axis, as viewed from the -X direction. Figure 3(a) is a diagram without the IC module 70, and Figure 3(b) is a diagram of Figure 3(a) with the IC module 70 installed.

As shown in Figure 1(a), the dual interface IC card 1 has the form of a thin, generally rectangular plate with rounded corners when viewed from the +Z direction. Furthermore, on the surface of the dual interface IC card on the +Z direction side, an IC module 70 including an external connection terminal 71 can be seen slightly to the upper left of the center, i.e., toward the -X direction and toward the +Y direction from the center. As shown in Figures 2(a) and 2(b), the IC module 70 is embedded in a recess 9 formed in the card base 2, and is positioned so that the surface of the external connection terminal 71 on the +Z direction side is generally flush with the surface of the card base 2 on the +Z direction side. This form of the dual interface IC card 1 complies with ISO/IEC 7816, the international IC card standard.

As shown in Figure 2(a), the card base 2 that constitutes the card body of the dual interface IC card 1 is formed by laminating and integrating, in order from the -Z direction, an oversheet layer 7, an inner layer 6, an antenna holding layer 5, an inner layer 4, and an oversheet layer 3. Typically, the oversheet layers 7 and 3 are transparent substrates, while the inner layers 6 and 4 and the antenna holding layer 5 are white substrates, but this is not limited to this. In addition, the antenna wire 83 that constitutes the antenna 80 is positioned between the antenna holding layer 5 and the inner layer 4 so that it is sandwiched between them.

The antenna wire 83 that constitutes this antenna 80 is partially exposed toward the IC module 70 in the area of the bottom surface 92p of the second recess 92a, which is formed relatively shallow within the recess 9. Outside of this area, the antenna wire 83 is completely buried within the card base 2. In other words, the antenna wire 83 is buried within the card base 2, but during the process of cutting the card base 2 to form the recess 9, a portion of the antenna wire 83 is cut along with the recess 9 to a degree that does not cause breakage, and the cut surface of the antenna wire 83 is exposed at the bottom surface 92p of the second recess 92a. The recess 9 further includes a first recess 91 that is deeper than the second recess 92a and formed along the outer periphery 97, and a third recess 93 that is deeper than the first recess 91 and formed closer to the center of the recess 9 than the second recess 92a.

As shown in FIG. 2(b), the IC module 70 is embedded so that the external connection terminals 71 and the substrate 72 supporting them are placed on the bottom surface 92p of the second recess 92a of the aforementioned recess 9. The substrate 72 and the antenna wire 83 exposed at the bottom surface 92p of the second recess 92a of the card base 2 are mechanically joined via the conductive adhesive layer 11. Incidentally, the third recess 93 houses the IC chip body 74, which is a protruding portion of the IC module 70. Furthermore, the surface of the substrate 72 opposite the external connection terminals 71 is provided with a terminal 73a electrically connected to the IC chip contained within the IC module 70. At this time, due to the effect of heat and pressure when embedding the IC module 70 in the recess 9 of the card base 2, the antenna wire 83 exposed at the bottom surface 92p and the terminal 73a are electrically connected via the conductive adhesive layer 11.

Here, both ends of the antenna wire 83 of the antenna 80, which is mostly embedded inside the card base 2 and partially exposed from the second recesses 92a and 92b, have the shape of end 84, as shown by the first end 81 and second end 82 in FIG. 1(b). The first end 81 and second end 82 are arranged parallel to each other on the left and right sides along the X axis, sandwiching the third recess 93 at the center of the recess 9. The first end 81 and second end 82, which are both ends of the antenna 80, are each configured by the antenna wire 83 repeatedly folding back from the outer periphery 97 of the second recesses 92a and 92b toward the center of the recess 9. In other words, the first end 81 and second end 82 are formed to have a structure known as a zigzag, meander, or bellows shape. In this way, by increasing the exposed area of the antenna wire 83 per unit area exposed in the recess 9, the reliability of the electrical connection between the terminal 73a of the IC module 70 and the antenna 80 can be improved.

Furthermore, within the region where the first end 81 and second end 82 are located, the first exposed portion 86 and the second exposed portion 87, which are the regions where the antenna wire 83 is exposed toward the +Z direction, are formed within the range of the second recesses 92a and 92b of the recess 9, respectively. Furthermore, the first recesses 91, which are separated from each other on the +Y direction side and the -Y direction side, are formed in the portion of the recess 9 excluding the third recess 93 and the second recesses 92a and 92b. Here, the second recesses 92a and 92b have approximately the same depth, and are both shallower than the first recess 91. To facilitate understanding, in Figure 1(b), the region of the first recess 91 is represented by a horizontal line pattern, and the regions of the second recesses 92a and 92b are represented by a dotted pattern. This also applies to Figures 5(a) and 6(b), which will be described later.

As shown in Figures 3(a) and 3(b), the recess 9 of the card base 2, where the substrate 72 of the IC module 70 is embedded, has two recesses of different depths: a first recess 91 and second recesses 92a and 92b. Therefore, the gap between the substrate 72 and the card base 2 varies depending on the location, and as a result, the thickness of the conductive adhesive layer 11 sandwiched between them after bonding varies. In other words, the depth of the recess 9 of the card base 2 facing the area of the substrate 72 where the terminal 73a is formed differs from the area spaced apart from the terminal 73a in the X direction. The second recess 92a faces the former area, and the first recess 91, which is deeper than the second recess 92a, faces the latter area.

Here, the terminal 73a is a layer formed of copper foil or the like of a predetermined thickness, and extends a predetermined distance in the same direction from the surface on the -Z direction side of the substrate 72. Therefore, when the IC module 70 is pressed against the card base 2 by applying heat and pressure, the depth of the second recess 92a is determined so that the distance between the terminal 73a via the conductive adhesive layer 11 and the antenna wire 83 exposed on the bottom surface 92p of the second recess 92a is within an appropriate range. In other words, good conductivity between the terminal 73a and the antenna wire 83 can be achieved at that distance.

However, in the region of the substrate 72 spaced apart from the terminal 73a along the Y-axis, even if the gap between the substrate 72 and the card base 2 is the distance described above, it is not necessarily possible to achieve a good mechanical connection between the IC module 70 and the card base 2. In other words, the gap conditions required for a good electrical connection between the terminal 73a and the antenna wire 83 are generally different from the gap conditions required for a good mechanical connection between the IC module 70 and the card base 2.

In contrast, in this embodiment, in the region of the substrate 72 spaced apart from the terminal 73a along the Y-axis direction, the gap between the substrate 72 and the card base 2 improves the adhesive strength between the IC module 70 and the card base 2, and the depth of the recess 9 in the card base 2 is changed to ensure a good mechanical connection between the two. Specifically, the recess 9 in this region is a first recess 91 that is deeper than the second recess 92a. The depth of the second recess 92a was determined taking into consideration the electrical connection between the terminal 73a, which extends out from the substrate 72 in the -Z direction, and the antenna wire 83.

If the depth of the recess 9 in the card base 2 were the same as the second recess 92a in the area where the terminal 73a is not present, the distance between the substrate 72 and the card base 2 would be too short, and the conductive adhesive layer 11 would be compressed more than necessary. As a result, the thickness of the conductive adhesive layer 11 required for mechanical connection between the IC module 70 and the card base 2 would not be secured, and the extruded adhesive component of the conductive adhesive layer 11 would protrude from the periphery of the IC module 70 to the outside of the card base 2. Furthermore, a thin conductive adhesive layer 11 is prone to cohesive failure when subjected to external forces such as tension, and mechanical adhesion strength may also be insufficient due to a wedge effect caused by the adhesive penetrating into minute irregularities on the surface of the substrate 72 or card base 2. This can lead to a decrease in the mechanical adhesive strength of the conductive adhesive layer 11 and poor appearance due to the protruding adhesive.

The dual interface IC card 1 of this embodiment can improve the reliability of both the electrical connection between the IC module 70 and the antenna 80 and the mechanical connection between the IC module 70 and the card base 2. Specifically, for the same conductive adhesive layer 11, the depth of the second recesses 92a, 92b, which improve the electrical connection between the IC module 70 and the antenna 80, is different from the depth of the first recess 91, which improves the mechanical connection between the IC module 70 and the card base 2. In other words, the second recesses 92a, 92b are formed shallower than the first recess 91.

By configuring the first recess 91 and the second recesses 92a and 92b in this manner, the electrical connection between the IC module 70 and the antenna 80 and the mechanical connection between the IC module 70 and the card base 2 can be achieved using the same conductive adhesive layer 11. This improves the efficiency of manufacturing the dual interface IC card 1. Furthermore, the appearance of the dual interface IC card 1 can be improved.

The following describes in detail the configuration of the dual interface IC card 1 of this embodiment and its manufacturing method.

(a) Card Base The card base 2 refers to the card body excluding the IC module 70 that constitutes the dual interface IC card 1. As described above, the card base 2 typically has a configuration in which an oversheet layer 7, an inner layer 6, an antenna holding layer 5, an inner layer 4, and an oversheet layer 3 are laminated in this order from one end in the −Z direction in the thickness direction. An antenna 80 wound in a loop shape and formed from a coated conductor wire or the like is disposed between the antenna holding layer 5 and the inner layer 4. The card base 2 may refer to both the card before the recess 9 is formed and the card after the recess 9 is formed, and may refer to both the card without the antenna 80 and the card with the antenna 80. The first end 81 and the second end 82, which are either the starting point or the ending point of the antenna 80, are formed by processing the antenna wire 83 into a predetermined shape, as described above.

However, the layer structure of the card base 2 is not limited to this, and may be a three-layer structure of inner layer, antenna holding layer, and inner layer, a two-layer structure of inner layer and inner layer, or a six-layer structure of over-sheet layer, inner layer, antenna holding layer, antenna holding layer, inner layer, and over-sheet layer. Furthermore, printing or an embedded magnetic stripe may be applied to the surface of over-sheet layer 3 or 7 of card base 2 opposite to inner layer 4 or 6, or printing may be applied to the surface of inner layer 4 or 6 adjacent to over-sheet layer 3 or 7.

In order to comply with standards such as ISO/IEC 7810, the thickness of the card base 2 is preferably 0.76 mm or more and 0.84 mm or less, but it may be outside this range.

(i) Inner Layer: A wide variety of white or colored plastic sheets can be used for the inner layers 4 and 6, including the following single films or composite films. The inner layer is also referred to as the core layer. Examples include polyethylene terephthalate (PET), PET-G (terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer), polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polycarbonate, polyamide, polyimide, cellulose diacetate, cellulose triacetate, polystyrene, ABS, polyacrylic ester, polypropylene, polyethylene, and polyurethane. The thickness of the inner layer sheet can be selected appropriately taking into account the overall thickness of the card, but can be, for example, approximately 0.25 mm or more and 0.38 mm or less. As described below, the antenna 80 must be positioned on the surface of either the antenna support layer 5 or the inner layer 4 so that it is sandwiched between the two layers.

(ii) Over-sheet Layers The over-sheet layers 3 and 7 are usually made of the same material as the inner layer, but are often made of a transparent material having a thickness of about 0.05 mm or more and 0.10 mm or less. From the viewpoint of preventing curling when the laminate of the inner layer and the over-sheet layer is integrated by heat pressing or the like, it is preferable that the over-sheet layers 3 and 7 have the same thickness, but they do not necessarily have to be the same.

The material of the over-sheet layer may be any material that is heat-adhesive. However, even if the over-sheet layer itself is not heat-adhesive, the inner layer and over-sheet layer can be integrated by adding a layer of a known adhesive that generates adhesive force when heated between them. Furthermore, when the dual interface IC card 1 is used as a magnetic card, a magnetic stripe may be embedded in advance by thermal transfer or other means on the main surface of either or both of the over-sheet layers 3 and 7 opposite the inner layers 4 and 6.

(iii) Antenna Retaining Layer In this embodiment, as described below, an antenna 80 is formed on one surface of the antenna retaining layer 5, and a first end 81 and a second end 82, which are ends 84 of an antenna wire 83 constituting the antenna 80, are each processed into a predetermined shape and arranged. The antenna 80 is formed on the antenna retaining layer 5 by applying a predetermined heat and pressure to the antenna wire 83 to embed it in the antenna retaining layer 5. The intermediate product in which the antenna 80 is embedded in the antenna retaining layer 5 is sometimes referred to as an antenna sheet 12. The antenna sheet 12 can be distributed on the market by itself as a component for manufacturing the dual interface IC card 1. Furthermore, a commercial model may exist in which a sheet material such as the antenna retaining layer 5 is supplied to a processor, who processes it into an antenna sheet 12 and delivers it to the supplier.

The method for forming the antenna sheet 12 will be described in detail later, but can be summarized as follows. First, a coated conductor coated with an insulating material is embedded into the surface of the antenna holding layer 5 using a wire winding machine, starting from either the first end 81 or the second end 82 and ending at the other. That is, while applying a predetermined heat and pressure to the antenna holding layer 5, an antenna supply head is drawn into a loop shape as shown in Figure 1(a), and the antenna wire 83 supplied from the antenna supply head is sequentially embedded into the antenna holding layer 5.

Here, the first end 81 and second end 82, which are either the starting point or the ending point of the antenna wire 83, are aligned to the left and right of the intended mounting position of the IC module 70, and are positioned so that portions of them overlap the terminals 73a and 73b of the IC module 70, to form a predetermined shape described below. The winding machine then cuts the antenna wire 83 after forming either the first end 81 or the second end 82, which are the ending points of the antenna 80. In this way, the antenna sheet 12 is completed.

In this embodiment, the antenna sheet 12 is formed by embedding the antenna wire 83 on one side of the antenna holding layer 5 using heat and pressure, but the form of the antenna sheet 12 is not limited to this. For example, the antenna sheet 12 may be formed by embedding the antenna wire 83 on the side of the inner layer 4 facing the antenna holding layer 5 using heat and pressure. In this case, the antenna sheet 12 is composed of the inner layer 4 and the antenna 80.

(iv) Antenna The antenna 80 formed on the antenna holding layer 5 has a first end 81 and a second end 82 electrically connected to terminals 73 a and 73 b of the IC module 70, respectively, so that the IC chip of the IC module 70 and the antenna 80 form a communication circuit for contactless communication. The communication circuit may be one that performs close-proximity communication using, for example, the 13.56 MHz HF frequency band specified by ISO/IEC 144443 or the like. Alternatively, the communication circuit may be one that performs communication using other frequency bands, such as the 920 MHz UHF frequency band, the 125 kHz LF frequency band, or the 2.45 GHz microwave frequency band.

When the dual interface IC card 1 is held over an external device such as a reader/writer, a current is generated in the communication circuit due to the magnetic field generated by the reader/writer, supplying power to the IC chip. This enables the IC chip to be driven, enabling contactless transmission and reception of information with the reader/writer and reading and rewriting of information from the memory.

The antenna wire 83 that makes up the antenna 80 is typically made of coated conductor wire, which is copper wire coated with an insulating material. However, other materials can also be selected, such as copper alloy wires such as Cu-Ni, Cu-Cr, Cu-Zn, Cu-Sn, and Cu-Be, or various metal wires and metal alloy wires such as iron, stainless steel, and aluminum. By using coated conductor wire, the dual interface IC card 1 can be manufactured more inexpensively than, for example, copper foil etching methods.

There are no particular restrictions on the diameter of the antenna wire 83, as long as it can maintain the characteristics of a contactless communication circuit. For example, it can be set to 0.03 mm or more and 0.30 mm or less, and preferably 0.05 mm or more and 0.15 mm or less. Setting it in the latter range improves durability against the thermal pressure caused by the embedding process and external forces caused by the cutting process, ensuring good communication characteristics.

Next, the configuration of the first end 81 and the second end 82 will be described in detail. In FIG. 1(b), one end of the antenna wire 83 extending from the -X direction toward the +X direction subsequently forms the first end 81, which has a structure that is repeatedly folded back from the outer periphery 97 toward the center near the -X direction side of the third recess 93 of the recess 9. Similarly, one end of the antenna wire 83 extending from the +X direction toward the -X direction subsequently forms the second end 82, which has a structure that is repeatedly folded back from the outer periphery 97 toward the center near the +X direction side of the recess 9. The antenna wire 83 extends so that the folded structure is repeated multiple times.

This folded structure has approximately arc-shaped bends at the +Y and -Y ends, i.e., the upper and lower ends, and the portion other than the bend connecting the upper end bend and the lower end bend is approximately straight or curved. However, from the perspective of efficiency in embedding the antenna wire 83 into the antenna holding layer 5 and saving material for the antenna wire 83, it is preferable to form the portion other than the bend as approximately straight as possible.

In this embodiment, the outer periphery 97 is a substantially rectangular shape with sides substantially parallel to the short and long sides of the card body 2. The first end 81 and the second end 82 are formed by a structure in which the antenna wire 83 constituting the antenna 80 repeatedly folds back from the -X side 97a and the +X side 97b of the outer periphery 97, which are sides of the recess 9 substantially parallel to the short sides of the card body 2, toward the center.

Furthermore, the portion of the first end 81 other than the bent portion of the folded structure extends along a straight line parallel to the Y axis along the side 97a of the outer periphery 97 of the recess 9, and the center-to-center distance, i.e., the pitch, of the zigzag-shaped antenna wires 83 between adjacent portions other than the bent portions is approximately constant. Furthermore, the width of the entire first end 81 and the first exposed portion 86 in the direction along the Y axis is W12, and the width of the exposed portion of the antenna wire 83 in the direction along the X axis is approximately the same as the width of the second recess 92a, so that the antenna wires 83 are arranged along the outline of a rectangle. The distance from the end on the +Y side of the folded structure to the end on the -Y side, i.e., the length from the top end to the bottom end, is approximately the same.

In addition, in this embodiment, the first exposed portion 86 of the first end 81, which is the region where the antenna wire 83 is actually exposed from the card base 2, includes a continuous section of the antenna wire 83 from the -X end of the second recess 92a to the +X end. In other words, the entire antenna wire 83, including the bent portion of the folded structure and the remaining portion, is exposed in the second recess 92a. The conductor is not covered by the card base 2 or a covering material, and the width W11 of the second recess 92a along the Y axis is equal to or greater than the width W12 of the first end 81 along the Y axis. The above description of the first end also applies to the second end 82 by replacing the side 97a of the recess 9 with 97b, the second recess 92a with 92b, and the first exposed portion 86 with the second exposed portion 87, respectively.

The pitch of the antenna wire 83 described above depends on factors such as the capacity of the winding machine and the quality of the antenna sheet 12 after the antenna wire 83 is embedded in the antenna retaining layer 5, but is preferably 0.50 mm or less, and more preferably 0.25 mm or less. By keeping the pitch within the former range, the exposed area of the antenna wire 83 per unit area at the first end 81 can be increased, expanding the area of electrical connection with the terminal 73a of the IC module 70. This improves the reliability of the electrical connection and reduces the electrical resistance at the contact points between the antenna wire 83 and the terminal 73a. Furthermore, by keeping the pitch within the latter range, the above-mentioned effects can be further enhanced.

In this embodiment, the +X end of the region of the first end 81 along the X axis is approximately the same as the boundary between the second recess 92a and the third recess 93, and the -X end is located further in the -X direction than the end of the second recess 92a, which is the outer periphery 97 of the recess 9. In this way, if the +X end of the first end 81 is approximately the same as the boundary between the second recess 92a and the third recess 93, or is located further in the -X direction than this, it is possible to not cut the antenna wire 83 when cutting the third recess 93, or to reduce the amount of cutting of the antenna wire 83. This makes it possible to suppress branching of the antenna wire 83, i.e., the occurrence of whiskers, which are more likely to occur the deeper the cutting depth.

Furthermore, the end of the first end 81 along the X direction is located closer to the -X direction than the end of the second recess 92a, which is the outer periphery 97 of the recess 9. This ensures that even if the antenna 80 is misaligned with respect to the antenna holding layer 5 or the recess 9 is not formed in the correct position, the densely packed area of the antenna wires 83 remains uninterrupted. This ensures a reliable electrical connection with the terminal 73a of the IC module 70. However, before the recess 9 is formed, the end of the first end 81 along the X direction may be located closer to the +X direction than the boundary between the second recess 92a and the third recess 93, or the end of the -X direction may be located closer to the +X direction than the end of the second recess 92a, which is the outer periphery 97 of the recess 9.

The above explanation concerns the relationship between the first end 81 of the antenna 80 and the terminal 73a of the IC module 70 that is electrically connected to it, but a similar relationship also applies between the second end 82 and the terminal 73b that is electrically connected to it. Furthermore, in this embodiment, the explanation was given on the assumption that the antenna 80 has two ends, the first end 81 and the second end 82, for electrically connecting with the IC module 70. However, the antenna 80 may have three or more ends 84, and the IC module 70 may have the same number of corresponding terminals.

(b) IC Module Next, each of the main components of the IC module 70 will be described mainly with reference to FIGS. 2(b) and 4. Similar to FIG. 1(a), FIG. 4(a) is a view of the external connection terminal 71 of the IC module 70 from the +Z direction. FIG. 4(b) is a view of the IC module 70 from the -Z direction, opposite to FIG. 4(a). Most of the molded portion 74b of the IC chip body 74 is omitted here to allow a see-through view of the interior. FIG. 4(c) is an enlarged cross-sectional view of portion C near the terminal 73a in FIG. 2(b).

The IC module 70 is embedded in a recess 9 formed in the card base 2, and the terminals 73a and 73b of the IC module 70 are electrically connected to the first end 81 and second end 82 of the antenna 80, respectively, thereby forming a communication circuit for contactless communication. Furthermore, contact communication with a contact-type reader/writer or the like can be performed via the external connection terminal 71 provided on the IC module 70.

Substrate 72 is made by bonding copper foil to both sides of a flexible insulating resin film, such as glass epoxy resin or polyimide resin, with an adhesive. The copper foil on both sides of the resin film is left to form a predetermined pattern. Specifically, external connection terminal 71 is formed on one copper foil surface of the resin film, and terminals 73a and 73b are formed on the other copper foil surface by sequentially applying a photosensitive material, placing a film plate with the predetermined pattern, exposing it to light, and etching away the non-photosensitive portions. This results in substrate 72, with portions of copper foil in the predetermined pattern remaining on both sides of the resin film. Substrate 72 also has multiple bonding holes 76, which are through-holes for wire bonding to external connection terminals 71, pre-formed in the substrate.

There are no particular restrictions on the thickness of the substrate 72, but taking into account the ability to follow the bending of the card base 2 to some extent, it can be, for example, 0.03 mm or more and 0.50 mm or less, and preferably 0.07 mm or more and 0.20 mm or less.

As shown in Figure 4(a), the external connection terminal 71 has each external terminal section defined by the ISO/IEC 7816-2 standard. As shown in Figure 4(b), each of these sections is connected to the IC chip 74a by wires 75, such as gold wires, through the aforementioned bonding holes 76 provided in the substrate 72. Similarly, terminals 73a and 73b are connected to the IC chip 74a by wires 75. These bonding holes 76 and wires 75 are covered and protected by the molded portion 74b.

An IC chip body 74 is disposed on the surface of the substrate 72 opposite the surface on which the external connection terminals 71 are formed. The IC chip body 74 is composed of an IC chip 74a adhered and fixed to the substrate 72 with an adhesive, bonding wires 75 for connection, and a molded portion 74b made of sealing resin to protect these. The IC chip 74a includes a CPU for controlling both contact and contactless communication operations, and storage devices such as RAM, ROM, EEPROM, and flash memory. The IC chip 74a also includes various circuits, such as an interface circuit that decodes input signals and generates output signals for contact and contactless communication, and a power generation circuit. Note that these various circuits may be provided as elements separate from the IC chip 74a.

The molded portion 74b is provided as a protruding portion that covers the IC chip 74a and wires 75 to protect them from external force loads and environmental loads. An insulating ultraviolet-curable resin or thermosetting resin, etc., is used for the molded portion 74b.

The thickness of the IC chip body 74 depends on the thickness of the IC chip 74a inside and the shape of the bonded wires, but can be, for example, 0.45 mm or more and 0.75 mm or less. The total thickness of the IC module 70 can be, for example, 0.35 mm or more and 1.0 mm or less, and preferably 0.40 mm or more and 0.65 mm or less. By keeping it within the latter range, the depth of the third recess 93 can be set to 0.7 mm or less, and the overall thickness of the dual interface IC card 1 can be kept to 0.84 mm or less, as specified in the ISO/IEC 7810 standard.

(c) Conductive Adhesive Layer After forming the recess 9 for embedding the IC module 70 in the card base 2 by cutting or the like using an end mill, the conductive adhesive layer 11 is described below, which embeds and fixes the IC module 70 in the recess 9 and electrically and mechanically connects it to the recess 9. As shown in Fig. 4(c) , the conductive adhesive layer 11 is disposed so as to be sandwiched between the antenna holding layer 5 in the portion where the antenna wire 83 is partially cut away and exposed on the bottom surface 92p, and the substrate 72 of the IC module 70 embedded and disposed above it and the terminal 73a formed on the substrate 72. The conductive adhesive layer 11 is a liquid or tape-like member.

The conductive adhesive layer 11 may be applied or affixed in advance to the surface of the substrate 72 of the IC module 70 opposite the external connection terminal 71, or may be applied or affixed to the bottom surface 92p of the recess 9 of the card base 2 after cutting.

A typical conductive adhesive layer 11 also serves as a mechanical connection between the IC module 70 and the cut card base 2, and may be applied or affixed to the entire back surface of the substrate 72 or to the areas of the recess 9 corresponding to the first recess 91 and the second recesses 92a, 92b. This allows the electrical connection between the IC chip 74a and the antenna 80 and the mechanical connection between the IC module 70 and the card base 2 to be achieved using the same type of conductive adhesive layer 11, contributing to simplification of the process.

On the other hand, the conductive adhesive layer 11 may be applied or affixed to the back surface of the substrate 72 so as to cover only the areas of the terminals 73a and 73b, and a different adhesive that is not conductive may be applied or affixed to the rest of the back surface of the substrate 72. Since the conductivity of the different adhesive does not need to be taken into consideration, it is easier to select an adhesive that is more advantageous for mechanical connection.

Conductive adhesive layer 11, which can provide both electrical and mechanical connection, can be made from ACF (Anisotropic Conductive Film), i.e., anisotropic conductive film, or ACP (Anisotropic Conductive Paste). Other materials that can be used include conductive paste, which is epoxy resin with silver particles dispersed as a filler. When using ACF, the ACF can be thermally laminated to the entire back surface of substrate 72 of IC module 70. After embedding IC module 70 in recess 9 of the card base 2 that has already been cut, the resulting assembly can be heat-pressed at a predetermined temperature and load. This facilitates electrical connection between IC chip 74a and antenna 80. Furthermore, mechanical connection of IC module 70 to card base 2 can also be achieved at the same time, simplifying the process of mounting IC module 70 to card base 2.

The electrical connection between the IC chip 74a and antenna 80 and the mechanical connection between the IC module 70 and card base 2 when ACF is used as the conductive adhesive layer 11 can be explained as follows, based on Figure 4(c). The conductive adhesive layer 11 is composed of conductive particles 11a, each consisting of spherical resin or metal particles with a metal film formed around them, dispersed in adhesive 11b, a binder containing an insulating adhesive component. Here, thermal pressure is applied to the substrate 72 from the +Z direction to the -Z direction so that the conductive adhesive layer 11, which is sandwiched between the antenna holding layer 5, from which a portion of the antenna wire 83 is exposed, and the substrate 72 of the IC module 70 and the terminal 73a formed on the substrate 72, is compressed.

As a result, strong thermal pressure is applied to the narrowly spaced portion of the conductive adhesive layer 11, sandwiched between the antenna holding layer 5 and the terminal 73a. The conductive particles 11a of the conductive adhesive layer 11 in this portion are then pressed against the exposed antenna wire 83 and terminal 73a of the antenna holding layer 5 along the thickness direction of the conductive adhesive layer 11. Furthermore, if the conductive particles 11a are small, they overlap in a daisy chain fashion along the thickness direction of the conductive adhesive layer 11, from the antenna wire 83 to the terminal 73a. In other words, the exposed antenna wire 83 and terminal 73a are electrically connected via the conductive particles 11a.

On the other hand, between the antenna holding layer 5 and the substrate 72 in areas where the terminals 73a are not present, the conductive particles 11a are not compressed to the extent that they are pressed against the antenna wire 83 and terminals 73a along the thickness direction of the conductive adhesive layer 11, or to the extent that they overlap in a daisy chain pattern. However, the adhesive force of the adhesive 11b generated by this thermal pressure mechanically connects the antenna holding layer 5 and the substrate 72. One possible reason for the adhesive force of the adhesive 11b is the wedge effect that occurs when the adhesive 11b penetrates into the minute irregularities on the surfaces of the antenna holding layer 5 and the substrate 72.

As described above, the IC module 70 has its opposing terminals 73a and 73b and its first end 81 and second end 82 electrically connected via, for example, an ACF. The ACF is arranged in a region along the outer periphery 97 of the recess 9 so as to overlap with the first recess 91 and second recesses 92a and 92b in a plan view along the Z-axis direction.

(d) Recess The recess 9 formed in the card base 2 for embedding the IC module 70 includes a portion of the outer periphery 97 and has a first recess 91 that is separated from one another. The recess 9 also has second recesses 92a and 92b adjacent to the first recess 91 and separated from one another, and a third recess 93 adjacent to the first recess 91 and formed closer to the center than the first recess 91 and the second recesses 92a and 92b. In this embodiment, as shown in FIG. 1B , the second recesses 92a and 92b are approximately rectangular regions in a plan view along the Z axis, located on either side of the central third recess 93 along the X axis. As described above, the first end 81 and the second end 82 of the antenna 80 overlap the second recesses 92a and 92b, respectively, and the overlapping regions define the first exposed portion 86 and the second exposed portion 87, which are exposed portions of the antenna wire 83.

On the other hand, the first recess 91 is adjacent to each of the second recesses 92a and 92b, and is a region divided and arranged on both sides along the Y axis, sandwiching the central third recess 93. In this embodiment, the first recess 91, the first end 81, and the second end 82 do not overlap each other in a plan view along the Z axis. The second recesses 92a and 92b have approximately the same depth, but are shallower than the first recess 91, and the third recess 93 is deeper than the first recess 91.

Here, as shown in FIG. 3(b), the depth d1 of the first recess 91 and the depth d2 of the second recesses 92a and 92b can be independently set as optimal depths for different purposes. That is, the depth d1 of the first recess 91 can be determined with consideration given to ensuring a good mechanical connection between the IC module 70 and the card base 2. Furthermore, the depth d2 of the second recesses 92a and 92b can be determined independently of the depth d1 of the first recess 91 with consideration given to ensuring a good electrical connection between the terminals 73a and 73b of the IC module 70 and the exposed antenna wire 83.

First, the depth d1 of the first recess 91 can be determined as follows. For example, let Tp1 be the thickness of the substrate 72, Tacf1 be the thickness of the conductive adhesive layer 11, Δacf1 be the amount of shrinkage of the conductive adhesive layer 11 in the thickness direction when a predetermined amount of heat and pressure is applied, and Δcb1 be the amount of shrinkage of the card base 2 in the thickness direction. In this case, if the surface of the external connection terminal 71 of the IC module 70 is approximately flush with the surface of the card base 2, the depth d1 of the first recess 91 is d1 = Tp1 + Tacf1 - Δacf1 - Δcb1. Here, the optimal d1 can be determined by determining the heat and pressure conditions (load, temperature, time, etc.) that maximize the adhesive strength between the IC module 70 and the card base 2, and by calculating Δacf1 and Δcb1 at that time.

Next, the depth d2 of the second recesses 92a and 92b can be determined as follows. For example, let Tp2 be the thickness of the terminal 73a extending from the substrate 72 in the -Z direction, Δacf2 be the amount of shrinkage of the conductive adhesive layer 11 in the thickness direction when a predetermined amount of heat and pressure is applied, and Δcb2 be the amount of shrinkage of the card base 2 in the thickness direction. The above definitions apply to the other dimensions. In this case, the depth d2 of the second recess 92a is d2 = Tp1 + Tp2 + Tacf1 - Δacf2 - Δcb2, but Δcb1 and Δcb2 are considered to be approximately the same regardless of whether the recess is the first recess 91 or the second recesses 92a and 92b. Here, the optimal d2 can be determined by determining the heat and pressure conditions that result in the best electrical connection between the terminal 73a of the IC module 70 and the exposed antenna wire 83, and by determining the corresponding Δacf2 and Δcb2 (or Δcb1).

Now, consider using the same conductive adhesive layer 11 for both the mechanical connection between the IC module 70 and the card base 2 and the electrical connection between the terminals 73a and antenna wire 83 of the IC module 70. In this case, the heat and pressure conditions applied to the IC module 70 described above are the same for the first recess 91 and the second recesses 92a, 92b. However, because the first recess 91 and the second recesses 92a, 92b have different depths, the repulsive force from the conductive adhesive layer 11 is stronger in the shallower second recesses 92a, 92b. As a result, the pressure conditions applied to the IC module 70 are a relatively light load in the first recess 91 and a relatively heavy load in the second recesses 92a, 92b. As a result, the amount of contraction Δacf2 of the conductive adhesive layer 11 in the thickness direction is greater than Δacf1.

Note that when the conductive adhesive layer 11 is an ACF and the average particle size of its conductive particles is dc1, Tacf1 > dc1 generally holds, and to ensure proper electrical connection, it is preferable that Tacf1 - Δacf2 = dc1 or Tacf1 - Δacf2 < dc1.

At this time, the conductive particles contained in the ACF filling the gap between the terminal 73a and the antenna wire 83 come into contact with both the terminal 73a and the antenna wire 83, either in that state or compressed, ensuring a reliable electrical connection. However, if the value of Tacf1 - Δacf2 is made extremely small, the conductive particles in the ACF may be destroyed, preventing a good electrical connection. To prevent such destruction of the conductive particles, it is preferable, for example, that Tacf1 - Δacf2 > (dc1)/2.

On the other hand, when the conductive adhesive layer 11 is an ACF, the appropriate value of Δacf1 for achieving a good mechanical connection between the IC module 70 and the card base 2 is estimated to be smaller than Δacf2, which is the condition for achieving the above-mentioned appropriate electrical connection. In particular, if the conductive adhesive layer 11 is expected to provide mechanical adhesion to the IC module 70 and the card base 2 through the wedge effect of the adhesive components, it is necessary for the conductive adhesive layer 11 to penetrate into the minute irregularities on the surfaces of the IC module 70 and the card base 2. It is also necessary to ensure a certain degree of thickness for the conductive adhesive layer 11. For this reason, it is preferable that the depth d2 of the second recess 92a be shallower by a predetermined amount than the depth d1 of the first recess 91.

For example, the depth of the first recess 91 is, for example, approximately 0.17 mm or more and 0.5 mm or less, and the depth of the second recesses 92a and 92b is, for example, approximately 0.12 mm or more and 0.4 mm or less. When the thickness of the terminals 73a and 73b is 0.015 mm or more and 0.15 mm or less, the difference between the depth of the second recesses 92a and 92b and the depth of the first recess 91 is preferably, as a first condition, approximately 0.005 mm or more and 0.1 mm or less. Furthermore, as a second condition, it is even more preferable that the difference be, as a second condition, approximately 0.005 mm or more and 0.03 mm or less. Furthermore, as a third condition, it is even more preferable that the difference be, as a third condition, approximately 0.01 mm or more and 0.02 mm or less.

The first condition allows for a wider range of options for the conductive adhesive layer 11. The second condition keeps the difference in depth between the first recess 91 and the second recesses 92a, 92b small, preventing the adhesive components of the conductive adhesive layer 11 from flowing from the second recesses 92a, 92b to the first recess 91, ensuring good mechanical adhesion in the second recesses 92a, 92b as well. The third condition effectively achieves both a mechanical connection between the IC module 70 and the card base 2 in the first recess 91 and prevention of the adhesive components from spilling out beyond the periphery of the IC module 70.

In this way, the cross section after the IC module 70 is mounted in the recess 9 of the card base 2 is as shown in Figures 3(a) and (b). That is, the thickness of the conductive adhesive layer 11 in the first recess 91 is d11, and the thickness of the conductive adhesive layer 11 in the second recess 92a is d22 in the area other than the terminal 73a and d3 in the area of the terminal 73a. When the above-mentioned conditions for improving the mechanical connection and the conditions for improving the electrical connection are both satisfied, the relationship d11 > d22 > d3 is generally satisfied.

The specific cutting order for forming such recesses 9 in the card base 2 can be determined arbitrarily depending on the milling program used in the cutting process. An exemplary cutting order determined from the perspective of improving processing time efficiency and ensuring cutting quality is as follows. For example, in FIG. 1(b), first, the area common to the first recess 91 and the second recesses 92a, 92b along the outer periphery 97 is cut to the depth of the second recesses 92a, 92b while moving the milling tool counterclockwise or clockwise. Next, the central areas are cut to the depth of the third recess 93, which is deeper than the first recess 91, while similarly moving the milling tool counterclockwise or clockwise.

Finally, the area common to the first recess 91 is cut by moving the milling tool to a depth deeper than the second recesses 92a and 92b but shallower than the third recess 93. Alternatively, only the second recess 92a may be cut by moving the milling tool counterclockwise or clockwise, and then only the second recess 92b may be cut in the same manner, followed by cutting the first recess 91. Alternatively, the milling tool may be moved left and right across the second recesses 92a and 92b, and cutting may be performed continuously while shifting it sequentially from top to bottom, thereby simultaneously forming the second recesses 92a and 92b.

(e) Method for Manufacturing Dual Interface IC Card Next, an example of a method for manufacturing the dual interface IC card 1 using the card base 2, IC module 70, and conductive adhesive layer 11 described above will be described.

First, the necessary components for constructing the card base 2 and dual interface IC card 1, including the antenna holding layer 5, inner layer 4, and IC module 70, are prepared. Next, a coated conductor covered with an insulating material is embedded as an antenna wire 83 on the surface of the antenna holding layer 5 facing the inner layer 4 using a wire winding machine, starting from either the first end 81 or the second end 82 and ending at the other. Specifically, for example, while applying a predetermined heat and pressure to the antenna holding layer 5, an antenna supply head is drawn into a loop shape as shown in FIG. 1(a), and the antenna wire 83 supplied from the antenna supply head is sequentially embedded in the antenna holding layer 5. The antenna holding layer 5 may also be referred to as the first substrate.

The antenna wire 83 is then positioned at predetermined positions to the left and right of the intended mounting position of the IC module 70 so that the first end 81 and the second end 82 are aligned in the left-right direction, and the antenna wire 83 is cut at its end point. The movement of the winding machine is changed to adjust the position of the antenna wire 83 so that the first end 81 and the second end 82 are formed by a repeated folding structure of the antenna wire 83 constituting the antenna 80, extending from the outer periphery 97 of the recess 9 toward the center. The antenna 80 is then embedded in the antenna holding layer 5 so that the portion of the antenna wire 83 other than the bent portion of the folding structure is aligned along a straight line parallel to the Y-axis, which is a straight line along the outer periphery 97, and so that the first end 81 and the second end 82 each follow a rectangular outline.

Next, as shown in Figure 2(a), using the antenna holding layer 5, which is the antenna sheet 12 on which the antenna 80 is formed, the oversheet layer 7, inner layer 6, antenna holding layer 5, inner layer 4, and oversheet layer 3 are stacked in this order from the bottom in the thickness direction. After that, each large-sheet laminate with cards arranged vertically and horizontally on multiple faces is sandwiched between stainless steel plates from above and below in the thickness direction, and heat and pressure are applied to the laminate via the stainless steel plates. The inner layer 4 that faces the antenna holding layer 5 and sandwiches the antenna 80, and the laminate of multiple layers including the inner layer 4, may also be referred to as the second substrate.

By undergoing this heat pressing process, a large-sized sheet-unit card base can be obtained in which each layer of the laminate is integrated. Furthermore, if any of the oversheet layer, inner layer, and antenna holding layer is heat-resistant and does not heat-seal at a predetermined temperature, the following can be done. That is, an adhesive sheet that heat-seals at a predetermined temperature is sandwiched between each layer, or an adhesive is applied, and then these are subjected to a heat pressing process to obtain an integrated large-sized sheet-unit card base.

The large-format card base obtained as described above, with the cards arranged vertically and horizontally in a multi-faceted configuration, is punched out using a punching machine to create the card base 2, which is the size of an ISO/IEC 7810 card. Furthermore, a recess 9 for embedding the IC module 70 is formed in the card base 2 by cutting using an end mill. This results in the cut card base 2. As mentioned above, the recess 9 is composed of a total of three levels: a first recess 91 and second recesses 92a and 92b for accommodating the flat substrate 72 of the IC module 70, and a third recess 93 for accommodating the convex IC chip body 74.

The depth of the first recess 91 is determined taking into consideration that the IC module 70 will be embedded and adhered to the card base 2, and that the surface of the external connection terminal 71 will be approximately flush with the surface of the non-cut area of the card base 2. The depth of the second recesses 92a and 92b corresponds to the embedding depth of the first end 81 and second end 82 of the antenna 80. In other words, when the second recesses 92a and 92b are formed by cutting, portions of the antenna wires 83 of the first end 81 and second end 82 are exposed at the bottom surface 92p.

In other words, the depth from the surface of the card base 2 on which the external connection terminals 71 are exposed to the bottom surface 92p of the second recesses 92a, 92b is defined as d2. Furthermore, the distance from this surface to the upper end of one of the antenna wires 83 at the first end 81 or the second end 82 is defined as d201, and the distance from this surface to the lower end of that one of the antenna wires 83 is defined as d202. Here, the relationship d201 < d2 < d202 holds for the values of d2, d201, and d202. If this relationship is not satisfied, the antenna wire 83 will break during the cutting process, or will not be exposed from the bottom surface 92p.

Separately from the manufacturing of the card base 2 and the cutting process for forming the recess 9, the conductive adhesive layer 11 is applied to the IC module 70. The IC module 70 is typically a module tape in which the IC module 70 is continuously formed on a long tape in one or two rows. A tape-shaped ACF is applied to the surface of the substrate 72 opposite the surface of the module tape on which the external connection terminals 71 are formed, while applying a certain amount of heat and pressure. The module tape with the ACF attached is then punched out with a punching machine into roughly rectangular IC modules 70 with rounded corners, yielding individual IC modules 70 with the conductive adhesive layer 11 attached.

The IC module 70, with the conductive adhesive layer 11 attached, is then embedded in the card base 2 with the recess 9 formed therein. A predetermined heat block is pressed against the external connection terminal 71, and a predetermined heat pressure is applied toward the card base 2 for a predetermined time. This melts the conductive adhesive layer 11, which is made of ACF, thereby establishing electrical connections between the terminals 73a and 73b of the IC module 70 and the first end 81 and second end 82 of the antenna 80, as well as mechanical connections between the IC module 70 and the card base 2. While the heat pressure conditions vary depending on the type and composition of the ACF, an example is a time of 0.5 seconds to 10.0 seconds, a temperature of 150°C to 250°C, and a pressure of 20 MPa to 100 MPa.

(f) Regarding the Dual Interface IC Card of the First Embodiment To summarize the above, the dual interface IC card 1 of the first embodiment includes a card base 2 and an antenna 80 disposed inside the card base 2 and having at least a plurality of ends 84, namely, a first end 81 and a second end 82. The dual interface IC card 1 further includes an IC module 70 having an IC chip 74a and a plurality of terminals 73a and 73b electrically connected to the IC chip 74a. The IC module 70 is disposed in a recess 9 provided in the card base 2 so that the plurality of terminals 73a and 73b facing each other and the plurality of first ends 81 and second ends 82 are electrically connected to each other.

The multiple ends 84, the first end 81 and the second end 82, are formed by a repeated folding structure of the antenna wire 83 that constitutes the antenna 80 from the outer periphery 97 of the recess 9 toward the center, and a portion of the structure is exposed in the recess 9, i.e., the second recesses 92a and 92b. This increases the exposed area of the antenna wire 83 per unit area exposed in the recess 9, improving the reliability of the electrical connection between the terminals 73a and 73b of the IC module 70 and the antenna 80.

This recess 9 includes a first recess 91 that includes a portion of the outer periphery 97 of the recess 9 and is separated from one another, and second recesses 92a and 92b that are adjacent to the first recess 91 and are separated from one another. Furthermore, the recess 9 includes a third recess 93 that is adjacent to the first recess 91 and is formed closer to the center of the recess 9 than the first recess 91 and the second recesses 92a and 92b. Furthermore, the first recess 91 is formed deeper than the second recesses 92a and 92b, and the third recess 93 is formed deeper than the first recess 91.

As a result, when the IC module 70 is pressed against the card base 2 by applying heat and pressure, the depth of the second recess 92a can be determined as follows. That is, the depth is determined so that the distance between the terminal 73a, which protrudes convexly from the substrate 72 via the conductive adhesive layer 11, and the antenna wire 83 exposed on the bottom surface 92p of the second recess 92a is within an appropriate range for electrical connection. Furthermore, in the region of the substrate 72 spaced apart from the terminal 73a along the Y-axis, the depth of the first recess 91 can be determined independently of the depths of the second recesses 92a and 92b so that the distance between the substrate 72 and the card base 2 is within an appropriate range for mechanical connection. Preferably, the depth of the first recess 91 can be adjusted to be deeper than the depths of the second recesses 92a and 92b to ensure good mechanical connection between the IC module 70 and the card base 2.

As a result, the dual interface IC card 1 of this embodiment can improve the reliability of both the electrical connection between the IC module 70 and the antenna 80 and the mechanical connection between the IC module 70 and the card base 2. Furthermore, even when the same conductive adhesive layer 11 is used, it is possible to achieve both the electrical connection between the IC module 70 and the antenna 80 and the mechanical connection between the IC module 70 and the card base 2. Furthermore, because the depth of the first recess 91 is greater than the depth of the second recesses 92a and 92b, the conductive adhesive layer 11 can be sufficiently thick, making it less likely to suffer from cohesive failure due to external forces such as tension. Furthermore, the wedge effect of the conductive adhesive layer 11 can be sufficiently ensured, and the appearance of the dual interface IC card 1 can be improved by suppressing the adhesive component from spilling out.

2. Second Embodiment Next, a dual interface IC card according to a second embodiment of the present disclosure will be described.

Figure 5(a) is a diagram showing the configuration of the first end 81a and second end 82a, which are end 84a of antenna 80a corresponding to Figure 1(b), of a dual interface IC card 1a of the second embodiment. Figure 5(b) is a diagram showing only the configuration of first end 81a of Figure 5(a). In the dual interface IC card 1a of this embodiment, the first end 81a and second end 82a are formed by a repeated folding structure of the antenna wire 83 that constitutes antenna 80a, from the outer periphery 97 of the recess 9a toward the center. Furthermore, a portion of this structure is exposed in the recess 9a, and the portion of the antenna 80a other than the bent portion of this folding structure is inclined with respect to a straight line along the outer periphery 97.

Of the first end 81a and second end 82a (end 84a), the bent regions of the folded structure where the antenna wire 83 is exposed are first exposed portions 86a and second exposed portions 87a that overlap the second recesses 95a and 95b in a plan view along the Z axis direction. At the first end 81a and second end 82a (end 84a), the portions other than the bent portions at the upper and lower ends of the folded structure are inclined obliquely with respect to straight lines m1 and m2, which are parallel to sides 97a and 97b along the outer periphery 97 of the first recess 91 and second recesses 95a and 95b, respectively. Straight lines m1 and m2 are parallel to the Y axis. Furthermore, the first end 81a and second end 82a are formed to follow the outline of a rectangle whose width along the X axis is W31 and whose width along the Y axis is W22.

When forming recess 9a by cutting, which has a substantially rectangular outer periphery that is roughly the same as that of IC module 70, the method for cutting second recesses 95a and 95b while exposing antenna wire 83 is the same as that described in the first embodiment. That is, in FIG. 5(a), first, the area common to first recess 91 and second recesses 95a, 95b along outer periphery 97 is cut to the depth of second recesses 95a, 95b while moving the milling tool counterclockwise or clockwise. Next, the central areas are cut to the depth of third recess 93, which is deeper than first recess 91, while moving the milling tool counterclockwise or clockwise in the same manner.

Finally, the area common to the first recess 91 is cut by moving the milling tool to a depth deeper than the second recesses 95a and 95b but shallower than the third recess 93. Alternatively, only the second recess 95a may be cut by moving the milling tool counterclockwise or clockwise, and then only the second recess 95b may be cut in the same manner, followed by cutting the first recess 91. Alternatively, the milling tool may be moved left and right across the second recesses 95a and 95b, and cutting may be performed continuously while shifting it sequentially from top to bottom, thereby simultaneously forming the second recesses 95a and 95b.

When cutting the second recess 95a or 95b, the milling tool moves along both the X-axis and the Y-axis. If the wiring direction of the antenna wire 83 and the direction of movement of the milling tool are roughly parallel, cutting the antenna wire 83 midway can cause unintended branching, resulting in the formation of whiskers. However, in this embodiment, the portions of the folded structure of the first end 81a and the second end 82a other than the bent portions at the top and bottom are inclined, thereby preventing the above-mentioned problem.

At the first end 81a, the portion other than the bent portion of the folded structure is inclined clockwise by a predetermined angle θ with respect to the Y axis, which is a straight line along the side 97a of the outer periphery 97 of the recess 9a. Here, the inclination angle θ is preferably 2 degrees or more and 20 degrees or less, and more preferably 5 degrees or more and 15 degrees or less. Furthermore, the inclination angle θ does not need to be strictly the same for all portions other than the bent portion of the folded structure, and may vary within the above-mentioned range. When the inclination angle θ is in the former range, the antenna wire 83 is inclined with respect to the X axis and Y axis, which are the directions of movement of the end mill when cutting the recess 9a, thereby preventing the antenna wire 83 from unintentionally branching.

On the other hand, by keeping the inclination angle θ within the latter range, it is possible to further suppress the occurrence of whiskers, which are branches of the antenna wire 83. Furthermore, even if the +X-direction end of the first end 81a before processing the recess 9a is located on the +X-direction side of the boundary between the second recess 95a and the third recess 93, it is possible to further reduce the area of disconnection of the antenna wire 83 caused by cutting the antenna wire 83 when cutting the third recess 93. This further improves the reliability of the electrical connection between the antenna 80a and the terminal 73a of the IC module 70.

In this embodiment, the +X end of the region of the first end 81a along the X-axis direction is approximately the same as the boundary between the second recess 95a and the third recess 93, and the -X end is located further in the -X direction than the end of the second recess 95a, which is the outer periphery 97 of the recess 9a. In this way, if the +X end of the first end 81a is approximately the same as the boundary between the second recess 95a and the third recess 93, or is located further in the -X direction, it is possible to either not cut the antenna wire 83 when cutting the third recess 93, or to reduce the amount of cutting of the antenna wire 83. This makes it possible to suppress branching of the antenna wire 83, i.e., the occurrence of whiskers, which are more likely to occur the deeper the cutting depth.

Furthermore, if the +X-direction end of the first end 81a before cutting is located further toward the +X-direction than the boundary between the second recess 95a and the third recess 93, the antenna wire 83 will be cut when the third recess 93 is cut, causing it to break midway. However, if the inclination angle θ is within the above-mentioned range, the area where the antenna wire 83 breaks can be reduced, ensuring a reliable electrical connection between the antenna 80a and the terminal 73a of the IC module 70.

Furthermore, if the +X-direction end of the first end 81a before machining the recess 9a is located on the +X-direction side of the boundary between the second recess 95a and the third recess 93, it is preferable to arrange the antenna wire 83 so that this area includes the bent portion with a folded structure, but does not include any other portion. By doing so, when cutting the third recess 93, the antenna wire 83 is less likely to branch from the bent portion that is at a large angle away from the direction along the Y-axis, which is the direction of end mill movement, thereby contributing to improved quality.

Note that at the second end 82a, the portion other than the bent portion of the folded structure is inclined counterclockwise, opposite to the first end 81a, by a predetermined angle θ with respect to the Y axis, which is a straight line along the side 97b of the outer periphery 97 of the recess 9a. Here, the range of the inclination angle θ is the same as that described for the first end 81a, except that the direction is reversed. The inclination of the portion other than the bent portion of the first end 81a with respect to the straight line along the outer periphery 97 and the inclination of the portion other than the bent portion of the second end 82a with respect to the straight line along the Y axis are formed line-symmetrically with respect to each other. In other words, the first end 81a and the second end 82a, including the inclination of the portion other than the bent portion of the antenna wire 83, are arranged symmetrically with respect to an axis along the Y axis.

As a result, when the antenna wire 83 is embedded in the antenna holding layer 5 to form the antenna sheet 12, the distortion and internal stress of the antenna holding layer 5 are offset and dispersed, making it possible to obtain a uniform antenna sheet 12 with little distortion and internal stress.

Furthermore, when embedding the IC module 70 in the recess 9a, the thermal pressure conditions applied between the first end 81a and the terminal 73a and the thermal pressure conditions applied between the second end 82a and the terminal 73b are symmetrical in the left-right direction. This prevents imbalances in the thermal pressure conditions and stabilizes the electrical connection between the IC module 70 and the antenna 80 and the mechanical connection between the IC module 70 and the card base 2.

However, the inclination of the first end 81a relative to a straight line along the outer periphery 97 of the portion other than the bent portion and the inclination of the second end 82a relative to a straight line along the outer periphery 97 of the portion other than the bent portion may not be line-symmetrical to each other and may be the same. In other words, the configuration of the antenna wire 83 of the second end 82a may be substantially the same as the configuration of the antenna wire 83 of the first end 81a, but shifted parallel to the +X direction. In this case, the effects and advantages of the configuration of the first end 81a described above also apply to the second end 82a.

3. Third Embodiment Next, a dual interface IC card according to a third embodiment of the present disclosure will be described.

Figure 6(a) is a plan view of the dual interface IC card 1b viewed from the +Z direction, corresponding to Figure 1(a). Figure 6(b) is a diagram corresponding to Figure 1(b) illustrating the arrangement of the antenna 80b with an enlarged view of the area near the external connection terminal 71. Figure 7(a) is a cross-sectional view of the dual interface IC card 1b of Figure 6(b) taken along line D-D parallel to the X axis, viewed from the -Y direction, corresponding to Figure 2(a). Figure 7(a) is a diagram corresponding to Figure 2(a) with the IC module 70 omitted, and Figure 7(b) is a diagram corresponding to Figure 2(b) with the IC module 70 mounted in Figure 7(a). Figure 8 is a cross-sectional view of the dual interface IC card 1b of Figure 6(b) taken along line E-E parallel to the Y axis, viewed from the -X direction, corresponding to Figure 3(a).

As shown in Figures 6(a) and 6(b), dual interface IC card 1b differs from the previously described embodiments in that both ends of antenna wire 83 of antenna 80b are not configured with a repeated folding structure from the outer periphery 97 of second recesses 96a and 96b toward the center of recess 9b. That is, in this embodiment, the first and second ends constituting end 100 formed at both ends of antenna wire 83 correspond to first plate 110 and second plate 120, which are end portions made of plate-shaped conductive material. In other words, antenna wire 83 constituting antenna 80b is wound around the periphery of the approximately rectangular card, and both ends are electrically connected to first plate 110 and second plate 120, which are a pair of conductive plate-shaped end 100.

The layer structure of the card base 2b of the dual interface IC card 1b is basically the same as that of the dual interface IC card 1 of the first embodiment. The only difference is that, instead of providing an antenna 80b on one surface of the antenna holding layer 5 with an antenna wire 83 and its two ends, a first end 81 and a second end 82, a first plate 110 and a second plate 120 welded to the antenna wire 83 and its two ends are provided. Therefore, a detailed description of the card base 2b will be omitted.

As shown in FIG. 7(a), the first plate 110 has a structure in which a first member 111 and a second member 112 are stacked, and the surface of the second member 112 is exposed at the bottom surface 96p of the second recess 96a. However, this is merely one example, and the first plate 110 and the second plate 120 may both be composed of a single member, or may both have a stacked structure of three or more layers of different members.

In this embodiment, the first member 111 and the second member 112 are made of conductive materials made of different metals, and the second member 112 is made of a conductive material made of a metal that is less susceptible to oxidation than the first member 111. As an example, the first member 111 can be made of copper and the second member 112 can be silver-plated, but this is not limited to this. The second plate 120 can also have the same configuration.

As mentioned above, terminals 73a and 73b are provided on the surface of the IC module 70 facing the card base 2b, which are electrically connected to the IC chip contained therein. As shown in FIG. 7(b), terminal 73a is electrically connected to the first plate 110 via the conductive adhesive layer 11, and the IC module 70 is also mechanically joined to the card base 2b via the conductive adhesive layer 11. The first plate 110 and second plate 120 are arranged on the card base 2b so that the second member 112 faces the opening side of the recess 9b and the first member 111 faces the side opposite the opening side of the recess 9b. The opening side of the recess 9b is the +Z direction side in FIG. 7(b).

The tip of the antenna wire 83 abuts the +Z direction side of the first plate 110, i.e., the second member 112, thereby establishing an electrical connection with the first plate 110. The terminal 73a of the IC module 70 also abuts the second member 112 of the first plate 110 via the conductive adhesive layer 11, thereby establishing an electrical connection with the first plate 110. This means that the first plate 110 only needs to have the necessary conductivity on the side facing the second member 112, expanding the range of materials that can be used for the first plate 110 to include insulating materials.

Furthermore, the first plate 110 has a laminated structure of the first member 111, which is a conductive member, and the second member 112, which is a conductive member that is less susceptible to oxidation than the first member 111, which is expected to have the following effects: The tip of the antenna wire 83 and the terminals 73a and 73b can all face the second member 112 and be electrically connected to the first plate 110, improving the reliability of the electrical connection between the tip of the antenna wire 83 and the terminals 73a and 73b and the first plate 110. The second member 112 is relatively resistant to oxidation, which makes it less likely that an oxide film will form on its surface. This increases the likelihood of good bonding between the antenna wire 83 and the first plate 110 when welding it to the first plate 110 or when using an anisotropic conductive film (ACF) as the conductive adhesive layer 11.

Furthermore, an oxide film is less likely to form on the surface of the second member 112. Therefore, when forming the recess 9b by cutting using an end mill or the like, it becomes difficult to obtain adhesive strength through hydrogen bonding or the like with the resin substrate of the inner layer 4 or the like laminated on the surface of the second member 112, which tends to reduce adhesion between the second member 112 and the resin substrate. Therefore, even if the cutting depth of the end mill blade is set slightly shallower, the resin substrate is more likely to peel off at the interface of the second member 112, allowing the surface of the second member 112 to be properly exposed in the recess 9b. This allows for a wider range of blade depth settings during cutting, improving yield and productivity. The same applies to the second plate 120.

As shown in FIG. 8, the recess 9b of the card base 2b, where the substrate 72 of the IC module 70 is embedded, has two recesses of different depths: a first recess 91 and a second recess 96a, as in the first embodiment. Although not shown, the depth and shape of the second recess 96b are similar to those of the second recess 96a. Therefore, the gap between the substrate 72 and the card base 2b varies depending on the location, resulting in a difference in the thickness of the conductive adhesive layer 11 sandwiched between them after bonding. In other words, the depth of the recess 9b of the card base 2b differs between the area of the substrate 72 where the terminal 73a is formed and the area spaced apart from the terminal 73a in the X direction. The second recess 96a faces the former area, and the first recess 91, which is deeper than the second recess 96a, faces the latter area.

In other words, in this embodiment, in the region of the substrate 72 spaced from the terminal 73a along the Y-axis direction, the gap between the substrate 72 and the card base 2b improves the adhesive strength between the IC module 70 and the card base 2b, and the depth of the recess 9b in the card base 2b is changed to ensure a good mechanical connection between them. Specifically, the recess 9b in this region is a first recess 91 that is deeper than the second recess 96a. The depth of the second recess 96a was determined taking into consideration the electrical connection between the terminal 73a extending from the substrate 72 in the -Z direction and the first plate 110. The same applies to the second recess 96b and the second plate 120.

As a result, the dual interface IC card 1b of this embodiment can improve the reliability of both the electrical connection between the IC module 70 and the antenna 80b and the mechanical connection between the IC module 70 and the card base 2b. Specifically, for the same conductive adhesive layer 11, the depth of the second recesses 96a, 96b, which improve the electrical connection between the IC module 70 and the antenna 80b, is different from the depth of the first recess 91, which improves the mechanical connection between the IC module 70 and the card base 2b. In other words, the second recesses 96a, 96b are formed shallower than the first recess 91.

By configuring the first recess 91 and the second recesses 96a, 96b in this manner, the electrical connection between the IC module 70 and the antenna 80 and the mechanical connection between the IC module 70 and the card base 2b can be achieved using the same conductive adhesive layer 11. This improves the efficiency of manufacturing the dual interface IC card 1b. Furthermore, the other effects described in the first embodiment can also be achieved in this embodiment.

1, 1a, 1b Dual interface IC card 2, 2b Card base 3, 7 Oversheet layer 4, 6 Inner layer 5 Antenna holding layer 8, 8a Antenna 9, 9a, 9b Recess 11 Conductive adhesive layer 11a Conductive particles 11b Adhesive 12 Antenna sheet 70 IC module 71 External connection terminal 72 Substrate 73a, 73b Terminal 74 IC chip body 74a IC chip 74b Molded portion 74p Pad 75 Wire 76 Bonding hole 80, 80a, 80b Antenna 81, 81a First end 82, 82a Second end 83 Antenna line 84 End 86, 86a, 86b First exposed portion 87, 87a, 87b Second exposed portion 91 First recess 92a, 92b, 95a, 95b, 96a, 96b Second recess 92p, 96p Bottom surface 93 Third recess 97 Outer periphery 97a, 97b Side 100 End 110 First plate 111 First member 112 Second member 120 Second plate

Claims (8)

A dual interface IC card capable of contact communication and contactless communication with an external device,
a card base having a recess;
an antenna having an end portion disposed within the card base;
an IC module having terminals electrically connected to the IC chip;
The recess includes a first recess that includes a portion of the outer periphery of the recess and is separated from the first recess;
a second recess adjacent to the first recess and separated from the first recess;
a third recess formed adjacent to the first recess and closer to the center of the recess than the first recess and the second recess,
In the second recess facing the IC module, the end is exposed from the card base toward the IC module,
the IC module is placed in the recess so that the terminals and the end portions are electrically connected;
A dual interface IC card, wherein the first recess is formed deeper than the second recess, and the third recess is formed deeper than the first recess. A dual interface IC card as described in claim 1, wherein the end portion is configured by a repeated folding structure of the antenna wire that constitutes the antenna from the outer periphery toward the center of the recess. A dual interface IC card as described in claim 1 or claim 2, wherein the outer periphery is a substantially rectangular shape with sides substantially parallel to the short and long sides of the card body, and the end portion is formed by a repeated folding structure from the outer periphery, which is a side of the recess substantially parallel to the short sides of the card body, toward the center by an antenna wire constituting the antenna. The dual interface IC card of claim 3, wherein the portion of the antenna other than the bent portion of the folded structure is inclined with respect to the straight line along the outer periphery. A dual interface IC card as described in claim 1, wherein the end portion is formed from a plate-shaped conductive member welded to the tip of the antenna wire that constitutes the antenna. A dual interface IC card according to any one of claims 1 to 5, wherein the terminals and ends of the IC module facing each other are electrically connected via an anisotropic conductive film. The dual interface IC card of claim 6, wherein the anisotropic conductive film is positioned so as to overlap the first recess and the second recess. A method for manufacturing a dual interface IC card capable of contact communication and contactless communication with an external device, comprising:
providing an IC module having a first substrate, a second substrate, and terminals electrically connected to an IC chip;
forming an antenna having an end on one surface of the first substrate;
a step of laminating the first base material and the second base material by thermal fusion or via an adhesive so as to sandwich the antenna therebetween to form a laminate;
a step of punching the laminate into a card size to form a card base;
forming a recess in the card base;
and placing the IC module in the recess so that the terminals and the end portions are electrically connected to each other,
The recess includes a first recess that includes a portion of the outer periphery of the recess and is separated from the first recess;
a second recess adjacent to the first recess and separated from the first recess;
a third recess formed adjacent to the first recess and closer to the center of the recess than the first recess and the second recess,
In the second recess facing the IC module, the end is exposed from the card base toward the IC module,
A method for manufacturing a dual interface IC card, wherein the first recess is formed deeper than the second recess, and the third recess is formed deeper than the first recess.