Antenna device and IC card

Abstract

The present invention provides an antenna device and an IC card that eliminate the step of applying ink to form an infrared absorption layer. [Solution] An IC card 100 comprising a card body 80, an antenna device 1, and an IC module 50, wherein the antenna device 1 comprises a support 13 and an antenna pattern 19 arranged on the first main surface 13a of the support 13, the support 13 having the characteristic that the maximum value of light transmission density is higher in the infrared region than in the visible light region, and the total light transmittance of the support 13 in the visible light region is 80% or more.

Description

Technical Field

[0001] The present disclosure relates to an antenna device and an IC card.

Background Art

[0002] Conventionally, an antenna device including a mesh-shaped conductor pattern has been known (for example, Patent Document 1). This antenna device has a support and an antenna pattern disposed on the support.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the above-described antenna device has been required to have infrared shielding properties in order to enable card detection when applied to a transparent card. Therefore, in the above-described antenna device, ink containing an infrared absorber is applied onto the substrate. However, when an infrared absorption layer is provided on the substrate by applying ink, there is a problem that sufficient visible light transmittance cannot be ensured. Therefore, an object of the present disclosure is to provide an antenna device and an IC card that overcome the above problems and can omit the printing process for forming an infrared absorption layer.

Means for Solving the Problems

[0005] An antenna device according to one aspect of the present disclosure is an antenna device including a support and an antenna pattern disposed on the support, wherein the support has a characteristic that the maximum value of the optical transmission density is higher in the infrared region than in the visible light region, and the total light transmittance of the support in the visible light region is 80% or more.

[0006] An IC card relating to one aspect of this disclosure comprises the above-described antenna device and an IC module. [Effects of the Invention]

[0007] According to one aspect of this disclosure, it is possible to provide an antenna device and an IC card that can omit the process of applying ink to form an infrared absorbing layer. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view showing the appearance of an IC card incorporating an antenna device according to one embodiment of the present disclosure. [Figure 2] This is an exploded perspective view of an IC card as seen from the bottom. [Figure 3] This is a cross-sectional view along the line III-III shown in Figure 1. [Figure 4] This is a plan view of the antenna device. [Figure 5] This is a magnified view of the area around the slit. [Figure 6] This is a magnified view of the area around the slit. [Figure 7] This is a magnified view of the area around the slit. [Figure 8] This is a magnified view of the area around the slit. [Figure 9] Figure 8 shows an overall view of the antenna pattern with slits. [Figure 10] This is a magnified cross-sectional view of the antenna device. [Modes for carrying out the invention]

[0009] Several embodiments of this disclosure are described in detail below. However, this disclosure is not limited to the embodiments described below.

[0010] Figure 1 is a schematic perspective view showing the external appearance of an IC card 100 incorporating an antenna device according to one embodiment of the present disclosure. The IC card 100 shown in Figure 1 is a plate-like body with the Y-axis direction as the short side, the X-axis direction as the long side, and the Z-axis direction as the thickness side, and has an upper surface a and a lower surface b that constitute the XY plane. The IC card 100 incorporates an IC module 50 and an antenna device, which will be described later, and the terminal electrodes E of the IC module are exposed on the upper surface a of the IC card 100. The IC card 100 can communicate via the antenna device by bringing it close to a card reader 110. The application examples of the IC card 100 are not particularly limited, but it may be applied to a transparent IC card that enables contactless communication in which the wires and conductor patterns constituting the antenna are not visible, for example, a transparent dual-interface card such as a bank card or credit card.

[0011] Figure 2 is an exploded perspective view of the IC card 100 as seen from the bottom surface b. Figure 3 is a cross-sectional view along the line III-III shown in Figure 1. Figure 3 shows the structure near the IC module 50. As shown in Figures 2 and 3, the IC card 100 comprises a card body 80, an antenna device 1, and an IC module 50. The card body 80 has an upper layer 5, a card substrate 2, and a lower layer 3. The IC card 100 has a structure in which the upper layer 5, card substrate 2, antenna device 1, and lower layer 3 are stacked in this order from the top surface a to the bottom surface b. The IC card 100 also includes an IC module 50. In this embodiment, the IC module 50 is located in the negative region in the X-axis direction of the IC card 100, and closer to the positive side in the Y-axis direction. However, the position of the IC module 50 is not particularly limited.

[0012] The card substrate 2 is a plate-shaped member that covers the negative main surface 1b in the Z-axis direction of the antenna device 1. The card substrate 2 is joined to the negative main surface 1b in the Z-axis direction of the antenna device 1. The upper layer 5 is joined to the negative main surface in the Z-axis direction of the card substrate 2 via an adhesive layer 12. The negative main surface in the Z-axis direction of the upper layer 5 constitutes the upper surface a of the IC card 100. The upper layer 5 is provided with a substantially rectangular IC mounting opening 4A. The IC mounting opening 4A penetrates the upper layer 5 in the thickness direction (Z-axis direction). The card substrate 2 is provided with a substantially rectangular IC mounting opening 4B. The IC mounting opening 4B penetrates the card substrate 2 in the thickness direction (Z-axis direction). An IC module 50 is placed inside the IC mounting openings 4A and 4B (see Figure 3). The lower layer 3 is a plate-shaped member that covers the positive main surface 1a in the Z-axis direction of the antenna device 1. The negative main surface in the Z-axis direction of the lower layer 3 constitutes the lower surface b of the IC card 100. The card base material 2 is bonded to the antenna device 1 via the adhesive layer 12. The lower layer 3 is bonded to the antenna device 1 via the adhesive layer 12.

[0013] The card substrate 2, lower layer 3, and upper layer 5 may be transparent resin substrates. The card substrate 2, lower layer 3, and upper layer 5 may be made of, for example, cellulose propionate (CP), polyvinyl chloride (PVD), polycarbonate (PC), tempered glass, etc. The thickness of the card substrate 2, lower layer 3, and upper layer 5 is not particularly limited, but may be 100 to 500 μm. The total light transmittance of the card substrate 2, lower layer 3, and upper layer 5 may be 90 to 100%. In the embodiment shown in Figure 3, the thickness of the card substrate 2 is formed to be greater than the thickness of the lower layer 3 and upper layer 5.

[0014] The adhesive layer 12 may be an adhesive sheet made of a highly transparent thermoplastic or thermosetting resin. The adhesive sheet material may be acrylic, urethane, epoxy, or phenolic. The adhesive layer 12 may be substrate-free, have high total light transmittance, and low haze. The thickness of the adhesive layer 12 is not particularly limited, but may be 10 to 100 μm. The total light transmittance of the adhesive layer 12 may be 90 to 100%.

[0015] FIG. 4 is a plan view of the antenna device 1. As shown in FIG. 4, the antenna device 1 is a rectangular plate-like member. The antenna device 1 has an edge portion 1c on the negative side in the X-axis direction, an edge portion 1d on the positive side in the X-axis direction, an edge portion 1e on the negative side in the Y-axis direction, and an edge portion 1f on the positive side in the Y-axis direction. In the present embodiment, the edge portions 1c and 1d are short sides, and the edge portions 1e and 1f are long sides.

[0016] The antenna device 1 includes a mesh-shaped conductor pattern 14 having a plurality of mesh portions 17 (see FIG. 5). The conductor pattern 14 is a mesh-shaped pattern including a plurality of regularly arranged mesh portions 17 (see FIG. 5) formed by a plurality of conductive lines intersecting each other. The details of the pattern configuration of the conductor pattern 14 will be described later. The conductor pattern 14 is formed on substantially the entire main surface 1a of the antenna device 1. The conductor pattern 14 has a rectangular shape corresponding to the shape of the main surface 1a. The conductor pattern 14 has an edge portion 14c on the negative side in the X-axis direction, an edge portion 14d on the positive side in the X-axis direction, an edge portion 14e on the negative side in the Y-axis direction, and an edge portion 14f on the positive side in the Y-axis direction.

[0017] In the conductor pattern 14, an opening 20 and a slit 21 extending from the opening 20 to the edge 14c of the conductor pattern 14 are formed as regions where the mesh portion 17 and the conductive lines (the first conductive line and the second conductive line described later) are not formed. The opening 20 and the slit 21 are regions where the conductive lines are omitted from a part of the conductor pattern 14. Note that at the locations corresponding to the opening 20 and the slit 21, the support 13 remains without being penetrated. The opening 20 is formed at the position where the IC module 50 is disposed. The opening 20 has a rectangular shape corresponding to the shape of the IC module 50. The slit 21 extends from the opening 20 to the edge 14c. The slit 21 extends from the side portion on the negative X-axis side of the opening 20 to the edge 14c on the negative X-axis side of the conductor pattern 14. The slit 21 extends parallel to the X-axis direction with a constant width. Note that the width of the slit 21 and the width of the opening 20 are dimensions in a direction orthogonal to the extending direction of the slit 21 and the penetrating direction of the opening 20, that is, the distance between the edges extending along the extending direction of the slit 21. The width (dimension in the Y-axis direction) of the slit 21 is smaller than the width (dimension in the Y-axis direction) of the opening 20.

[0018] As shown in FIG. 3, the antenna device 1 includes a support 13 and a conductor pattern 14 (antenna pattern 19) provided on one first main surface 13a of the support 13. The conductor pattern 14 extends in a direction along the first main surface 13a of the support 13 and has a plurality of mesh portions 17 (see FIG. 5). The conductor pattern 14 has a conductor portion 18 (see FIG. 5) that forms the mesh portion 17. Details of the characteristics of the support 13 will be described later.

[0019] In the opening 20, a through hole penetrating the conductor pattern 14 in the Z-axis direction is formed. Therefore, the opening 20 is a region where the conductor pattern 14 does not exist.

[0020] The conductor pattern 14 is placed on the lower layer 3 via the adhesive layer 12. In the example shown in Figure 3, the conductor pattern 14 is placed on the support 13. Within the IC card 100, the support 13 is located on the negative side in the Z-axis direction, and the conductor pattern 14 is located on the positive side in the Z-axis direction. Therefore, the layers are stacked in the order of upper layer 5, card substrate 2, support 13, conductor pattern 14, and lower layer 3, from the negative side to the positive side in the Z-axis direction.

[0021] The IC module 50 comprises a module substrate 51 and an IC chip 52 mounted or embedded therein. A coupling coil 53 is formed on the positive side of the module substrate 51 in the Z-axis direction (see also Figure 2). Terminal electrodes E, as shown in Figure 1, are provided on the surface side of the module substrate 51.

[0022] The IC module 50 is placed within the IC mounting openings 4A and 4B. The inner surfaces of the IC mounting openings 4A and 4B are positioned to surround the IC module 50 from the outer side. The IC module 50 is positioned opposite the opening 20 of the antenna device 1 at a position on the negative side in the Z-axis direction. The size of the opening 20 in the Y-axis and X-axis directions is smaller than that of the IC module 50. Also, the size of the opening 20 in the Y-axis and X-axis directions is smaller than the outer edge of the coupling coil 53 and larger than the inner edge of the coupling coil 53. Therefore, when viewed from the Z-axis direction, the four inner surfaces of the opening 20 are positioned to overlap with the four sides of the coupling coil 53. The IC mounting opening 4A of the upper layer 5 is larger than that of the module substrate 51. The IC mounting opening 4B of the card substrate 2 is smaller than that of the module substrate 51 and smaller than that of the coupling coil 53. The coupling coil 53 is joined to the stepped portion of the card substrate 2 via hot melt tape 46. Note that the IC card 100 is not limited to the structure shown in Figure 3.

[0023] Next, the function of the antenna device 1 will be explained with reference to Figure 4. A current CA flows through the coupling coil 53 (see Figure 2) of the IC module 50. In Figure 4, the current CA is assumed to flow counterclockwise. At this time, the magnetic flux B (see Figure 2) of the coupling coil 53 acts on the edge of the opening 20. As a result, a clockwise eddy current CB flows through the conductor pattern 14 near the edge of the opening 20. In this way, the conductor pattern 14 near the edge of the opening 20 functions as a coupling coil that magnetically couples with the coupling coil 53 of the IC module 50. Here, the conductor pattern 14 at the negative edge in the X-axis direction of the opening 20 is divided by the slit 21 up to the edge 14c. Therefore, the eddy current CB is divided by the slit 21, and currents CCa and CCb flow along the slit 21 in the X-axis direction. A current CCa flows through the conductor pattern 14 at the negative edge in the Y-axis direction of the slit 21, from the opening 20 toward the edge 14c. As a result, a counterclockwise current CD flows throughout the entire conductor pattern 14. A current CCb flows through the conductor pattern 14 at the positive edge of the slit 21 in the Y-axis direction, returning from the edge 14c side to the opening 20. In this way, the antenna device 1 can function as an antenna because a current flows through the entire conductor pattern 14 in the same direction as the IC module 50.

[0024] Next, the conductor pattern 14 will be described in detail with reference to Figure 5(a). Figure 5 is an enlarged view of the area near the slit 21. As shown in Figure 5(a), the conductor pattern 14 includes a plurality of first conductive wires 30 and a plurality of second conductive wires 31. The first conductive wires 30 are linear conductive portions 18 extending parallel to the X-axis direction. The plurality of first conductive wires 30 are arranged to be spaced apart from each other in the Y-axis direction. The plurality of first conductive wires 30 are arranged to be spaced apart at equal pitches. The second conductive wires 31 are linear conductive portions 18 extending parallel to the Y-axis direction. The plurality of second conductive wires 31 are arranged to be spaced apart from each other in the X-axis direction. The plurality of second conductive wires 31 are arranged to be spaced apart at equal pitches. The line width of the conductive wires 30,31 is not particularly limited, but may be set to, for example, 1 to 50 μm or 1 to 3 μm. Furthermore, the pitch of the conductive wires 30 and 31 is not particularly limited, but may be set to, for example, 50 to 1000 μm or 50 to 200 μm. The first conductive wire 30 and the second conductive wire 31 have a wire thickness greater than their wire width. The wire thickness of the conductive wires 30 and 31 is the dimension in the Z-axis direction. Therefore, the cross-sectional shape of the conductive wires 30 and 31 has a shape that extends in the Z-axis direction (see Figure 3). The wire thickness of the conductive wires 30 and 31 is not particularly limited, but may be set to, for example, 1 to 10 μm or 2 to 5 μm.

[0025] In this embodiment, the first conductive wire 30 is substantially parallel to the X-axis direction, which is the direction in which the slit 21 extends. The other second conductive wire 31 is substantially perpendicular to the X-axis direction, which is the direction in which it extends. Note that the first conductive wire 30 does not have to be parallel to the X-axis direction as long as it extends in the X-axis direction, and the second conductive wire 31 does not have to be parallel to the Y-axis direction as long as it extends in the Y-axis direction.

[0026] The normal mesh portions 17 other than those near the slits 21 and the openings 20 will now be described. Each mesh portion 17 is composed of a pair of adjacent first conductive wires 30 and a pair of adjacent second conductive wires 31. In this embodiment, each mesh portion 17 has a square shape. However, if the pitch of the first conductive wires 30 and the pitch of the second conductive wires 31 are different, the mesh portion 17 will be rectangular. The pitch of the mesh portion 17 in the Y-axis direction is equal to the pitch of the first conductive wires 30. The pitch of the mesh portion 17 in the X-axis direction is equal to the pitch of the second conductive wires 31. The width of the slit 21 (dimension in the Y-axis direction) may be greater than the pitch of the mesh portion 17 in the Y-axis direction. The width of the slit 21 may be greater than, equal to, or less than the pitch of the mesh portion 17 in the X-axis direction. In the mesh portion 17, the first conductive wire 30 and the second conductive wire 31 only need to intersect, and do not necessarily need to be perpendicular. That is, a mesh portion 17 in which the first conductive wire 30 and the second conductive wire 31 intersect at an angle may be used.

[0027] In the example shown in Figure 5(a), first conductive wires 30 extending in the X-axis direction are formed at both ends of the slit 21 in the Y-axis direction. Thus, a slit 21 with a border is formed. Alternatively, as shown in Figure 5(b), the ends of the slit 21 in the Y-axis direction may not have the first conductive wires 30, and the mesh portion may be open to the slit 21. In Figures 5(a) and 5(b), the slit 21 has a shape that extends in a straight line in the X-axis direction (see trajectory TL).

[0028] Furthermore, as shown in Figure 5(c), the slit 21 may be formed by extending the broken portion 40, where the second conductive wire 31 is broken, from the opening 20 to the edge 14c (see Figure 4). The method of forming the broken portion 40 is not limited; the second conductive wire 31 may originally exist, and a portion may be removed to form the broken portion 40, or the broken portion 40 may be formed by not providing a conductive wire in the area corresponding to the broken portion 40 during the stage of forming the second conductive wire 31. The state of continuous broken portions 40 means that at least two conductive wires constituting one mesh portion 17 have broken portions 40, and adjacent cells of the mesh portion 17 are connected by the broken portions 40. In this case, when viewed from the extending direction of the slit 21, there may be portions where adjacent broken portions 40 in the extending direction do not overlap. In this embodiment, the extending direction of the slit 21 is the X-axis direction. For example, the row of mesh portion 17 in which the slit 21 is formed is defined as region E1. A break portion 40 is formed in a part of each second conductive wire 31 within region E1. The second conductive wire 31A has a break portion 40a near its positive end in the Y-axis direction within region E1. The break portion 40a is formed from the first conductive wire 30 on the positive side in the Y-axis direction within region E1 to a position spaced away from the first conductive wire 30 toward the negative side in the Y-axis direction. The second conductive wire 31B adjacent to the second conductive wire 31A has a break portion 40b near its negative end in the Y-axis direction within region E1. The break portion 40b is formed from the first conductive wire 30 on the negative side in the Y-axis direction within region E1 to a position spaced away from the first conductive wire 30 toward the positive side in the Y-axis direction. When viewed from the X-axis direction, adjacent break portions 40a and 40b are arranged so as not to overlap and do not have any overlapping portions. The patterns of the broken sections 40a and 40b are repeated in the X-axis direction. As a result, the slit 21 has a shape that extends in a zigzag trajectory TL along the X-axis direction. Thus, the trajectory TL drawn in the slit 21 that passes through each broken section 40 does not extend in a straight line, but rather extends while curving.

[0029] The configuration in which the trajectory TL of the slit 21 extends while curving is not limited to the example shown in Figure 5(c), and Figures 6 to 8 may also be adopted. For example, as shown in Figure 6(a), the broken sections 40a and 40b may be positioned closer to the center of region E1 than in Figure 5(c). In this case, the broken sections 40a and 40b are positioned at a distance from the first conductive wire 30 at the edge of the slit 21.

[0030] In the example shown in Figure 5(c), the zigzag trajectory TL formed by the broken section 40 was continuously formed for each second conductive wire 31. Alternatively, as shown in Figure 6(b), the zigzag trajectory TL formed by the broken section 40 does not have to be continuous for each second conductive wire 31. The second conductive wire 31A has a broken section 40a near its positive end in the Y-axis direction in region E1. The second conductive wire 31B adjacent to the second conductive wire 31A has a broken section 40b near its positive end in the Y-axis direction within region E1. The second conductive wire 31C adjacent to the second conductive wire 31B has a broken section 40c near its negative end in the Y-axis direction within region E1. The second conductive wire 31D adjacent to the second conductive wire 31C has a broken section 40d near its negative end in the Y-axis direction within region E1. The second conductive wire 31E adjacent to the second conductive wire 31D has a break 40e near its positive end in the Y-axis direction within region E1. The trajectory TL between the break 40a and the break 40b extends in the X-axis direction on the positive side of the Y-axis direction. The trajectory TL between the break 40b and the break 40c extends in the X-axis direction, inclined toward the negative side of the Y-axis direction with respect to the X-axis direction. The trajectory TL between the break 40c and the break 40d extends in the X-axis direction on the negative side of the Y-axis direction. The trajectory TL between the break 40d and the break 40e extends in the X-axis direction, inclined toward the positive side of the Y-axis direction with respect to the X-axis direction. In this way, the breaks 40a, 40b, 40c, 40d, and 40e form a zigzag pattern in the trajectory TL, and this pattern is repeated in the X-axis direction.

[0031] An example shown in Figure 6(c) may be adopted. The second conductive wire 31A has a break 40a near the positive end in the Y-axis direction in region E1. The second conductive wire 31B adjacent to the second conductive wire 31A has a break 40b near the central position in the Y-axis direction within region E1. The second conductive wire 31C adjacent to the second conductive wire 31B has a break 40c near the negative end in the Y-axis direction within region E1. The second conductive wire 31D adjacent to the second conductive wire 31C has a break 40d near the central position in the Y-axis direction within region E1. The second conductive wire 31E adjacent to the second conductive wire 31D has a break 40e near the positive end in the Y-axis direction within region E1. The trajectory TL, which is two pitches between the break 40a and the break 40c, extends so as to be inclined toward the negative side in the Y-axis direction. The trajectory TL between the broken section 40c and the broken section 40e extends inclined toward the positive side in the Y-axis direction. In this way, the broken sections 40a, 40b, 40c, 40d, and 40e form a zigzag pattern in the trajectory TL, and this pattern is repeated in the X-axis direction. Furthermore, the zigzag pattern is inclined over a distance of two pitches. Thus, the pitch of the zigzag pattern shown in Figure 6(c) is longer than the pitch of the zigzag pattern shown in Figure 5(c).

[0032] The example shown in Figure 7(a) may also be adopted. The broken sections 40a and 40b shown in Figure 7(a) are located further towards the center than the broken sections 40a and 40b shown in Figure 6(a). When viewed from the X-axis direction, the adjacent broken sections 40a and 40b are arranged so that they do not overlap in some parts, but do overlap in others.

[0033] An example shown in Figure 7(b) may be adopted. The second conductive wire 31A has a break 40a near the positive end in the Y-axis direction in region E1. The second conductive wire 31B adjacent to the second conductive wire 31A has a break 40b near the central position in the Y-axis direction within region E1. The second conductive wire 31C adjacent to the second conductive wire 31B has a break 40c near the negative end in the Y-axis direction within region E1. The second conductive wire 31D adjacent to the second conductive wire 31C has a break 40d near the positive end in the Y-axis direction within region E1. The break 40d is located at the same position as the break 40a. The trajectory TL, which is two pitches long, between the break 40a and the break 40c extends so as to be inclined toward the negative side in the Y-axis direction. The trajectory TL for one pitch between the broken section 40c and the broken section 40d extends inclined toward the positive side in the Y-axis direction. In this way, the broken sections 40a, 40b, 40c, and 40d form a zigzag pattern in the trajectory TL, and this pattern is repeated in the X-axis direction. Furthermore, the zigzag pattern has an asymmetrical shape. That is, when the second conductive wire 31C is used as the reference axis, the pattern on the positive side of the X-axis and the pattern on the negative side of the X-axis are asymmetrical.

[0034] An example shown in Figure 7(c) may be adopted. The conductive wires 30 and 31 are inclined at 45° with respect to the X-axis and Y-axis directions. Of the rows of mesh portions 17 arranged in the X-axis direction, half of the region in the Y-axis direction is defined as region E1. The first conductive wire 30A has a break 40a near the negative end in the Y-axis direction within region E1. The second conductive wire 31B intersecting the first conductive wire 30A has a break 40b near the positive end in the Y-axis direction within region E1. The first conductive wire 30C intersecting the second conductive wire 31B has a break 40c near the negative end in the Y-axis direction within region E1. The second conductive wire 31D intersecting the first conductive wire 30C has a break 40d near the positive end in the Y-axis direction within region E1. Viewed from the X-axis direction, adjacent broken sections 40a and 40b are arranged so as not to overlap, and there are no overlapping portions between them. The patterns of broken sections 40a and 40b are repeated in the X-axis direction. As a result, the slit 21 has a shape that extends in a zigzag trajectory TL along the X-axis direction. Therefore, the trajectory TL of the slit 21 extends in a curved manner.

[0035] The example shown in Figure 8 may also be adopted. In the example shown in Figure 8, unlike the example in Figure 7(c), the slit 21 extends from the opening 20 in the direction of the arrangement of the mesh portion 17. That is, the slit 21 extends at an angle of 45° with respect to the X-axis and Y-axis directions. As shown in Figure 8(a), the slit 21 extends from the opening 20 toward the edge portion 14c at an angle toward the positive side in the Y-axis direction. The example shown in Figure 8(b) has a zigzag pattern of the disconnected portion 40, which is the same as the configuration in Figure 5(c) but at an angle of 45° with respect to the X-axis and Y-axis directions.

[0036] Next, the layer structure of the conductive wires 30 and 31 will be described with reference to Figure 10. As shown in Figure 10(a), the conductive wires 30 and 31 have a main body portion 33, a first blackened layer 34, and a second blackened layer 36. The conductive wires 30 and 31 have a surface F1 on the side facing the support 13 and a surface F2 on the opposite side from the support 13. The surface F1 on the side facing the support 13 is placed on the main surface 13a of the support 13.

[0037] The main body 33 may contain a metal. The main body 33 may contain at least one metal selected from copper, nickel, cobalt, palladium, silver, gold, platinum, and tin, and may contain copper. The main body 33 may further contain nonmetallic elements such as phosphorus, to the extent that appropriate conductivity is maintained.

[0038] The first blackening layer 34 is a layer provided on the surface F1 on the support 13 side. The first blackening layer 34 is provided between the main body 33 and the support 13. The second blackening layer 36 is provided on the surface F2 opposite to the support 13. The second blackening layer 36 is provided on the main body 33. The blackening layers 34 and 36 are darker than the main body 33. The thickness of the blackening layers 34 and 36 may be thinner than the thickness of the main body 33. The thickness of the main body 33 may be 1 to 10 μm. In contrast, the thickness of the blackening layers 34 and 36 may be 0.001 to 5 μm. The first blackening layer 34 may be made of a conductive resin. Specifically, the conductive resin may contain conductive particles, an organic polymer resin, and a black pigment. The conductive particles may be made of the same materials as those listed for the main body 33. The organic polymer resin may be made of materials such as polyester, acrylic, or urethane. For example, when forming conductive wires 30 and 31, a first blackened layer 34 is formed on the support 13 by screen printing. A metal body 33 is grown on this first blackened layer 34 by plating. The material of the second blackened layer 36 may be metal. The second blackened layer 36 may be a black plating layer such as a black nickel plating layer, a black chromium plating layer, or a nickel-tin alloy plating layer, or a palladium substitution layer formed on the body 33. The second blackened layer 36 may also be formed by a blackening treatment in which a part of the surface of the body 33 is replaced with a compound containing another metal. Due to the difference in materials of each blackened layer 34 and 36, the conductivity of the second blackened layer 36 may be higher than that of the first blackened layer 34.

[0039] The configuration shown in Figure 10(b) may be adopted. The conductive wires 30 and 31 shown in Figure 10(b) have metal layers 37 and 38 instead of the second blackened layer 36. The metal layers 38 and 37 are layers provided on the surface F2 opposite to the support 13. The metal layer 37 is formed on the main body 33 by plating or the like. The metal layer 38 is formed on the metal layer 37 by plating or the like. The metal layer 38 has the surface F2 of the conductive wires 30 and 31. Unlike the second blackened layer 36, the metal layers 37 and 38 are metals that do not contain black pigment. For example, gold, nickel, silver, etc. may be used as the metals of the metal layers 37 and 38. The surface side of the metal layers 37 and 38 may be gold or silver. The metal layers 37 and 38 contain different metals from each other. For example, the metal of metal layer 38 may be gold, and the metal of metal layer 37 may be nickel. The reflectivity of the metal layers 37 and 38 may be high in the main body 33.

[0040] Furthermore, as shown in Figure 10(c), the metal layers 37 and 38 may be omitted from Figure 10(b). In this case, the main body 33 has the surface F2 of the conductive wires 30 and 31.

[0041] As shown in Figure 10(d), a resin layer 16 may be formed to fill the mesh portion 17. The resin layer 16 is formed on the support 13 between the conductive wires 30 and 31. When adopting the configuration shown in Figure 10(d), a resin layer 16 with trenches may first be formed on the support 13, and the conductive wires 30 and 31 may be formed in the trenches. The resin layer 16 is made of a light-transmitting resin. The total light transmittance of the resin layer 16 may be 90 to 100%. The haze of the resin layer 16 may be 0 to 5%.

[0042] The resin forming the resin layer 16 may be a cured product of a curable resin composition (photocurable resin composition or thermosetting resin composition). The curable resin composition forming the resin layer 16 includes a curable resin, and examples include acrylic resins, amino resins, cyanate resins, isocyanate resins, polyimide resins, epoxy resins, oxetane resins, polyesters, allyl resins, phenolic resins, benzoxazine resins, xylene resins, ketone resins, furan resins, COPNA resins, silicon resins, diclopentadiene resins, benzocyclobutene resins, episulfide resins, ene-thiol resins, polyazomethine resins, polyvinyl benzyl ether compounds, acenaphthylene, and ultraviolet-curable resins containing unsaturated double bonds and functional groups that undergo polymerization reactions under ultraviolet light, such as cyclic ethers and vinyl ethers.

[0043] The method for manufacturing the antenna device 1 is not limited to the method described above. For example, an antenna pattern 19 may be formed on a separate sheet, and the antenna pattern 19 may be transferred to the support 13 via an adhesive or the like.

[0044] Next, the characteristics of the support 13 will be described. The support 13 has the infrared absorption properties required for an IC card 100, as well as the light transmittance properties required for a transparent IC card 100. The following descriptions of the light transmittance density and total light transmittance characteristics of the support 13 in this embodiment describe the characteristics inherent in the support 13 material itself. In other words, the support 13 in this embodiment is distinct from, for example, a material on which an infrared absorbent ink is coated onto a substrate that does not have infrared absorption properties.

[0045] Support 13 has the characteristic that the maximum light transmission density is higher in the infrared region than in the visible light region. Support 13 may have the characteristic that the light transmission density in the infrared region is higher than the light transmission density in the visible light region. However, there may be parts near the boundary between the visible light region and the infrared region where the light transmission density is locally higher in the visible light region. Support 13 may also have the characteristic that the peak of the light transmission density is located in a region above the lower limit of the wavelength range in the infrared region. The region above the lower limit of the wavelength range in the infrared region is the infrared region and the region with wavelengths longer than the infrared region. Therefore, the peak of the light transmission density may be located in the infrared region or in a region with wavelengths longer than the infrared region. In addition, there may be multiple peaks of light transmission density, some of which may be located in the infrared region. The wavelength of the visible light region is 380 to 780 nm, and the wavelength of the infrared region is 780 nm to 1 mm. Support 13 may have a region where the light transmission density in the infrared region is greater than 0.7, and may have a region where it is greater than 1. The support 13 may have a region in the visible light region where the light transmission density is less than 0.1.

[0046] The total light transmittance is the transmittance at a wavelength of 550 nm, measured using a haze meter (NDH8000) manufactured by Nippon Denshoku Industries Co., Ltd. This transmittance is the total light transmittance including diffusely transmitted light, determined using an integrating sphere. The light transmission density is the light transmission density measured using a spectrophotometer with an aperture of 8 mm, a spectral range of 400 nm to 1000 nm, and a built-in integrating light diffusion chamber.

[0047] Furthermore, the support 13 may have a light transmission density greater than 1.3 in the wavelength range of 800 nm to 950 nm, and a light transmission density greater than 1.1 in the wavelength range of 950 nm to 1000 nm. This allows the IC card 100, including the antenna device 1, to satisfy the characteristics of an IC card as defined in "ISO / IEC 7810".

[0048] The total light transmittance of the support 13 in the visible light region may be 80% or more, and may be 90% or more. There is no particular upper limit set for the total light transmittance; for example, it may be 100% or less.

[0049] The thickness of the support 13 is not particularly limited, but may be, for example, 10 μm or more, 20 μm or more, or 35 μm or more, and may be 500 μm or less, 200 μm or less, or 100 μm or less.

[0050] The material of the support 13 may be one that satisfies the above-mentioned light transmission density and total light transmittance.

[0051] Next, the operation and effects of the antenna device 1 and the IC card 100 according to this embodiment will be described.

[0052] In the antenna device 1, the support 13 has the characteristic that the maximum light transmission density is higher in the infrared region than in the visible light region. That is, the support 13 itself has the characteristic of absorbing infrared rays. Therefore, the antenna device 1 can block infrared rays without printing an infrared absorption layer on the support. As a result, when the antenna device is applied to an IC card, card detection becomes possible. Furthermore, the total light transmittance of the support 13 in the visible light region is 80% or more. The support 13 has infrared absorption properties while also having the light transmittance necessary for a transparent card. For these reasons, the printing process for forming an infrared absorption layer can be omitted.

[0053] The support 13 may have the characteristic that the peak of its light transmission density is located in a region above the lower limit of the wavelength range in the infrared region. In this case, the support 13 can exhibit light absorption in the infrared region, and therefore can exhibit sufficient infrared absorption as an antenna device.

[0054] The support 13 may have a region where the light transmission density in the infrared region is greater than 0.7. In this case, the support 13 can exhibit sufficient infrared absorption as an antenna device.

[0055] The support 13 may have a light transmission density greater than 1.3 in the wavelength range of 800 nm to 950 nm, and a light transmission density greater than 1.1 in the wavelength range of 950 nm to 1000 nm. In this case, the antenna device can satisfy the characteristics required for an IC card.

[0056] The antenna pattern 19 has a conductor pattern 14 formed by arranging multiple conductive wires 30, 31 in a mesh-like manner. The conductor pattern 14 may have an opening 20 in which the conductive wires 30, 31 are not formed, and a slit 21 extending from the opening to the edge of the conductor pattern 14. In this case, an antenna capable of magnetic coupling with the IC chip 52 can be realized while ensuring transparency.

[0057] The slit 21 is formed by extending the broken sections 40 where the conductive wires 30 and 31 are disconnected from the opening 20 to the edge, and the trajectory TL drawn in the slit 21 passing through each broken section 40 may extend in a curved manner. Here, a slit 21 in which the trajectory TL extends in a straight line (such as in Figures 5(a) and 5(b)) is easily visible because the area where the conductive wires 30 and 31 are absent has a certain shape. On the other hand, if the slit 21 extends in a zigzag pattern and the trajectory TL extends in a curved manner, the area where the conductive wires 30 and 31 are absent is dispersed, making it difficult to see. Therefore, the visibility of the slit 21 can be suppressed. For example, Figure 9 shows the antenna pattern 19 when the slit 21 in Figure 8 is minimized. By drawing a zigzag pattern as shown in Figure 8(b), the position of the slit 21 is difficult to see in Figure 9. This effect of suppressing visibility can also be obtained when using the slits 21 shown in Figures 5(c), 6, and 7, in addition to Figure 8.

[0058] The conductive wires 30 and 31 constituting the antenna pattern 19 may have a first blackening layer 34 constituting the surface F1 on the support side 13 and a second blackening layer 36 constituting the surface F2 opposite to the support 13. In this case, the blackening layers 34 and 36 are less visible than the surface of the main body 33 which has light reflectivity. Therefore, the first blackening layer 34 can suppress the visibility of the conductive wires 30 and 31 when the antenna device 1 is viewed from the surface F1 side. The second blackening layer 36 can suppress the visibility of the conductive wires 30 and 31 when the antenna device 1 is viewed from the surface F2 side.

[0059] The conductivity of the second blackening layer 36 may be higher than that of the first blackening layer 34. Since the second blackening layer 36 does not need to function as a base for forming the main body 33, unlike the first blackening layer 34, increasing its conductivity can improve the conductivity of the entire antenna pattern 19.

[0060] The conductive wires 30 and 31 constituting the antenna pattern 19 each have a main body 33 and metal layers 37 and 38 provided on the surface F2 opposite to the support 13, and the surface of the metal layers 37 and 38 may be gold or silver. In this case, if a specific color is to be given to the antenna pattern 19, the color can be adjusted by adjusting the material of the metal layers 37 and 38 provided on the surface F2.

[0061] The thickness of the metal layers 37 and 38 may be thinner than that of the main body. In this case, the amount of metal in the metal layers 37 and 38 can be reduced to the amount necessary for adjusting the color.

[0062] The IC card 100 comprises the antenna device 1 described above and the IC module 50.

[0063] The IC card 100 can achieve the same functions and effects as the antenna device 1 described above.

[0064] This disclosure is not limited to the embodiments described above.

[0065] For example, the IC card configuration shown in Figure 3 is just one example and may be modified as needed.

[0066] [Form 1] Support and An antenna device comprising an antenna pattern disposed on the support, The support has the characteristic that the maximum light transmission density is higher in the infrared region than in the visible light region. An antenna device wherein the total light transmittance of the support in the visible light region is 80% or more. [Form 2] The antenna device according to Embodiment 1, wherein the support has the characteristic that the peak of the light transmission density is located in a region above the lower limit of the wavelength range in the infrared region. [Form 3] The antenna device according to Embodiment 1 or 2, wherein the support has a region in the infrared region where the light transmission density is greater than 0.7. [Form 4] The antenna device according to Embodiment 3, wherein the support has a light transmission density greater than 1.3 in the wavelength range of 800 nm to 950 nm and a light transmission density greater than 1.1 in the wavelength range of 950 nm to 1000 nm. [Form 5] The antenna pattern has a conductor pattern formed by arranging multiple conductive wires in a mesh-like manner. The antenna device according to any one of embodiments 1 to 4, wherein the conductor pattern has an opening which is a region in which the conductive wire is not formed, and a slit which extends from the opening to the edge of the conductor pattern. [Form 6] The antenna device according to Embodiment 5, wherein the slit is formed by extending the broken portion of the conductive wire from the opening to the edge, and the trajectory drawn in the slit to pass through each broken portion extends in a curved manner. [Form 7] The antenna device according to any one of embodiments 1 to 6, wherein the conductive wire constituting the antenna pattern has a first blackened layer constituting the surface on the support side and a second blackened layer constituting the surface on the opposite side of the support. [Form 8] The antenna device according to Embodiment 7, wherein the conductivity of the second blackened layer is higher than that of the first blackened layer. [Form 9] The antenna device according to any one of embodiments 1 to 8, wherein the conductive wire constituting the antenna pattern comprises a main body and a metal layer provided on the surface opposite to the support, and the surface of the metal layer is gold or silver. [Form 10] The antenna device according to form 9, wherein the thickness of the metal layer is thinner than that of the main body. [Form 11] An antenna device according to any one of Forms 1 to 10, An IC card equipped with an IC module. [Explanation of Symbols]

[0067] 1...Antenna device, 13...Support, 14...Conductor pattern, 19...Antenna pattern, 20...Opening, 21...Slit, 30...First conductive wire, 31...Second conductive wire, 33...Main body, 34...First blackened layer, 36...Second blackened layer, 37,38...Metal layer, 40...Broken wire section, 50...IC module, 100...IC card.

Claims

1. Support and An antenna device comprising an antenna pattern disposed on the support, The support has the characteristic that the maximum light transmission density is higher in the infrared region than in the visible light region. An antenna device wherein the total light transmittance of the support in the visible light region is 80% or more.

2. The antenna device according to claim 1, wherein the support has the characteristic that the peak of the light transmission density is located in a region above the lower limit of the wavelength range in the infrared region.

3. The antenna device according to claim 1, wherein the support has a region in the infrared region where the light transmission density is greater than 0.

7.

4. The antenna device according to claim 3, wherein the support has a light transmission density greater than 1.3 in the wavelength range of 800 nm to 950 nm and a light transmission density greater than 1.1 in the wavelength range of 950 nm to 1000 nm.

5. The antenna pattern has a conductor pattern formed by arranging multiple conductive wires in a mesh-like manner. The antenna device according to claim 1, wherein the conductor pattern has an opening which is a region in which the conductive wire is not formed, and a slit which extends from the opening to the edge of the conductor pattern.

6. The antenna device according to claim 5, wherein the slit is formed by extending the broken portion of the conductive wire from the opening to the edge, and the trajectory drawn in the slit to pass through each broken portion extends in a curved manner.

7. The antenna device according to claim 5, wherein the conductive wire constituting the antenna pattern has a first blackened layer constituting the surface on the support side and a second blackened layer constituting the surface on the opposite side of the support.

8. The antenna device according to claim 7, wherein the conductivity of the second blackened layer is higher than that of the first blackened layer.

9. The antenna device according to claim 1, wherein the conductive wire constituting the antenna pattern comprises a main body and a metal layer provided on the surface opposite to the support, and the surface of the metal layer is gold or silver.

10. The antenna device according to claim 9, wherein the thickness of the metal layer is thinner than that of the main body.

11. An antenna device according to any one of claims 1 to 10, An IC card equipped with an IC module.

Images