RFID module and wireless communication device

Abstract

This RFID module has: a substrate that comprises first and second outermost layers; a coil conductor that extends in a first direction along the substrate; and an RFIC chip that is electrically connected to the coil conductor. The coil conductor includes a plurality of semi-annular conductors that each comprise two ends provided on the first outermost layer, and are arranged side by side in the first direction, a plurality of conductor patterns that are provided side by side in the first direction on a different layer from the first outermost layer, and a plurality of interlayer connection conductors that are provided side by side in the first direction between the first outermost layer and the layer where the conductor patterns are provided, and electrically connect the plurality of semi-annular conductors and the respectively corresponding conductor patterns.

Description

RFID module and wireless communication device

[0001] The present disclosure relates to an RFID module and a wireless communication device including the same.

[0002] For example, Patent Document 1 discloses an RFID tag (wireless communication device) in which a power supply module (RFID module) is disposed within a coil spring-shaped antenna. The RFID module has a printed wiring board and a power supply coil (coil conductor) provided on the printed wiring board and magnetically coupled with the antenna. The coil conductor includes multiple conductor patterns formed on the printed wiring board, multiple metal pins extending from both ends of each conductor pattern, and multiple conductor patterns connecting the distal ends of each metal pin.

[0003] International Publication No. 2018 / 101315

[0004] However, in order to achieve stronger magnetic field coupling with the coil spring antenna, it is necessary to enlarge the coil opening of the coil conductor of the RFID module. However, in the case of the RFID module described in Patent Document 1, enlarging the coil opening requires increasing the size of the RFID module by lengthening the multiple metal pins, for example.

[0005] Therefore, an object of the present disclosure is to enlarge the coil opening of the coil conductor in an RFID module having a coil conductor that magnetically couples with a coil spring-shaped antenna while maintaining the overall size of the RFID module small.

[0006] In order to solve the above technical problems, according to one aspect of the present disclosure, there is provided an RFID module having: a substrate having first and second outermost layers; a helical coil conductor extending in a first direction along the substrate; and an RFIC chip electrically connected to the coil conductor, wherein the coil conductor has both ends provided on the first outermost layer with a gap between them in a second direction intersecting the first direction, and includes: a plurality of semi-annular conductors lined up in the first direction; a plurality of conductor patterns provided on a layer different from the first outermost layer and lined up in the first direction; and a plurality of interlayer connection conductors provided between the first outermost layer and the layer on which the conductor patterns are provided and lined up in the first direction, electrically connecting each of the plurality of semi-annular conductors to the corresponding conductor pattern.

[0007] According to another aspect of the present disclosure, there is provided a wireless communication device having: a coil spring antenna; and the RFID module described above that is disposed within the antenna and magnetically coupled with the antenna.

[0008] According to the present disclosure, in an RFID module having a coil conductor that magnetically couples with a coil spring-shaped antenna, the coil opening of the coil conductor can be enlarged while maintaining the overall size of the RFID module small.

[0009] Schematic partial perspective perspective view of an RFID module according to embodiment 1 of the present disclosure; Schematic cross-sectional view of an RFID module according to embodiment 1 of the present disclosure; Equivalent circuit diagram of an RFID module according to embodiment 1 of the present disclosure; Schematic exploded perspective view of an RFID module according to embodiment 1 of the present disclosure; Schematic exploded perspective view of an RFID module in a wireless communication device according to embodiment 2 of the present disclosure; Schematic exploded perspective view of an RFID module in a wireless communication device according to embodiment 3 of the present disclosure; Schematic cross-sectional view of an RFID module according to embodiment 3 of the present disclosure; Schematic exploded perspective view of an RFID module in a wireless communication device according to embodiment 4 of the present disclosure; Schematic exploded perspective view of an RFID module in a wireless communication device according to embodiment 5 of the present disclosure

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0011] First Embodiment FIG. 1 is a perspective view of a wireless communication device according to a first embodiment of the present disclosure.

[0012] 1, a wireless communication device 10 according to the first embodiment includes a coil spring-shaped antenna 20 and an RFID (Radio Frequency Identification) module 30 that performs wireless communication using the antenna 20. The RFID module 30 is disposed inside the antenna 20 and performs wireless communication with an external communication device (not shown) by magnetically coupling with the antenna 20.

[0013] FIG. 2 is a schematic, partially perspective view of an RFID module according to a first embodiment of the present disclosure. FIG. 3 is a schematic cross-sectional view of the RFID module. FIG. 4 is an equivalent circuit diagram of the RFID module. FIG. 5 is a schematic exploded perspective view of the RFID module. Note that the X-Y-Z Cartesian coordinate system in the figures is intended to facilitate understanding of the embodiments of the present disclosure and does not limit the embodiments of the present disclosure. The X-axis direction indicates the longitudinal direction of the RFID module 30, the Y-axis direction indicates the lateral direction, and the Z-axis direction indicates the thickness direction. Furthermore, as shown in FIG. 1, the X-axis direction also corresponds to the opening direction of the antenna 20, i.e., the direction in which the coil axis C1 extends.

[0014] 2, in the case of the first embodiment, the RFID module 30 has a rectangular parallelepiped shape that can be placed within the antenna 20 shown in Fig. 1. The RFID module 30 also has a substrate 32, a coil conductor 34 provided on the substrate 32, and an RFIC (Radio Frequency Integrated Circuit) chip 36 electrically connected to the coil conductor 34.

[0015] The substrate 32 of the RFID module 30 includes a first outermost layer 32a and a second outermost layer 32b that are exposed to the outside of the substrate 32. In the case of the first embodiment, both end surfaces of the substrate 32 in the thickness direction (Z-axis direction) are the first outermost layer 32a and the second outermost layer 32b. Furthermore, in the case of the first embodiment, the substrate 32 has a rectangular shape with a longitudinal direction (X-axis direction) and a lateral direction (Y-axis direction) when viewed in the thickness direction (Z-axis direction), and is made of an insulating material such as glass epoxy resin or ceramic.

[0016] The substrate 32 is provided with a coil conductor 34 for magnetically coupling with the antenna 20. Specifically, in the case of the first embodiment, the coil conductor 34 is a conductor that extends helically in the longitudinal direction (X-axis direction) of the substrate 32. That is, the coil conductor 34 is provided on the substrate 32 so that its coil axis C2 is substantially parallel to the longitudinal direction of the substrate 32. Further details of the coil conductor 34 will be described later.

[0017] The substrate 32 is also provided with an RFIC chip 36 that is electrically connected to the coil conductor 34. In the first embodiment, the RFIC chip 36 is provided on the first outermost layer 32a of the substrate 32, and is adjacent to the coil conductor 34 in the length direction (X-axis direction) when viewed in the thickness direction (Z-axis direction).

[0018] In the first embodiment, a sealing resin block 38 is formed on the first outermost layer 32a of the substrate 32 as a member for protecting the coil conductor 34 and the RFIC chip 36, and embeds the coil conductor 34 and the RFIC chip 36. The sealing resin block 38 and the substrate 32 form the rectangular parallelepiped shape of the RFID module 30.

[0019] From here, specific features of the coil conductor 34 will be described.

[0020] As shown in FIGS. 3 and 5, the coil conductor 34 includes a plurality of semi-annular conductors 40, a plurality of conductor patterns 42, and a plurality of interlayer connection conductors 44, 46 that electrically connect these.

[0021] The multiple semi-annular conductors 40 of the coil conductor 34 are components made of a conductive material, for example, a metal material such as copper. In the first embodiment, the semi-annular conductors 40 are in the shape of a square bracket. However, the semi-annular conductors 40 may have a shape other than the square bracket shape, for example, an arc shape. The multiple semi-annular conductors 40 are arranged on the first outermost layer 32a of the substrate 32 at intervals in the longitudinal direction (X-axis direction) of the substrate 32.

[0022] Each semi-annular conductor 40 is provided, via both ends thereof, on the first outermost layer 32a of the substrate 32. Specifically, each semi-annular conductor 40 is composed of two columnar bases 40a, 40b provided on the first outermost layer 32a and a connecting portion 40c connecting the bases 40a, 40b. When multiple semi-annular conductors 40 are provided on the first outermost layer 32a of the substrate 32, in each semi-annular conductor 40, the two bases 40a, 40b are in contact with the first outermost layer 32a at an interval in the short-side direction (Y-axis direction) of the substrate 32, and the connecting portion 40c faces the first outermost layer 32a at an interval in the thickness direction (Z-axis direction).

[0023] In the first embodiment, a plurality of electrodes 48, 50 are provided on the first outermost layer 32a of the substrate 32, which faces the two base portions 40a, 40b of each of the plurality of semi-annular conductors 40. That is, the plurality of electrodes 48, 50 are arranged in two rows in the longitudinal direction (X-axis direction) and spaced apart in the lateral direction (Y-axis direction) of the substrate 32. The two base portions 40a, 40b of each semi-annular conductor 40 are fixed and electrically connected to the electrodes 48, 50 via a conductive adhesive 52 such as solder.

[0024] Each of the multiple conductor patterns 42 of the coil conductor 34 is strip-shaped and made of a conductive material, such as copper. The multiple conductor patterns 42 are arranged side by side at intervals in the longitudinal direction (X-axis direction) of the substrate 32 on a layer of the substrate 32 different from the first outermost layer 32a on which the semi-annular conductor 40 is provided. In the case of the first embodiment, the multiple conductor patterns 42 are arranged on the second outermost layer 32b.

[0025] In the first embodiment, each of the multiple conductor patterns 42 extends obliquely with respect to the longitudinal direction (X-axis direction) of the substrate 32. That is, each conductor pattern 42 extends in both the longitudinal direction and the lateral direction (Y-axis direction). As a result, one end of each conductor pattern 42 faces one base portion 40a of one semi-annular conductor 40 in the thickness direction (Z-axis direction), while the other end faces the other base portion 40b of the adjacent semi-annular conductor 40 in the thickness direction. In the first embodiment, an electrode 48 is present between one end of the conductor pattern 42 and one base portion 40a of the semi-annular conductor 40, and an electrode 50 is present between the other end and the other base portion 40b.

[0026] The multiple interlayer connection conductors 44, 46 of the coil conductor 34 are, for example, through-hole conductors formed by filling holes formed in the substrate 32 with a conductive material. In the case of the first embodiment, the interlayer connection conductors 44, 46 are provided between the first outermost layer 32 a and the second outermost layer 32 b, i.e., they penetrate the substrate 32.

[0027] The plurality of interlayer connection conductors 44, 46 electrically connect each of the semi-annular conductors 40 provided on the first outermost layer 32a to the corresponding conductor pattern 42.

[0028] Specifically, in the first embodiment, each of the multiple interlayer connection conductors 44 is electrically connected to one base portion 40 a of the corresponding semi-annular conductor 40 via an electrode 48 and solder 52, and is also electrically connected to one end of the corresponding conductor pattern 42. Furthermore, each of the multiple interlayer connection conductors 46 is electrically connected to the other base portion 40 b of the corresponding semi-annular conductor 40 via an electrode 50 and solder 52, and is also electrically connected to one end of the corresponding conductor pattern 42. As a result, one end of each conductor pattern 42 is electrically connected to one base portion 40 a of one of the two adjacent semi-annular conductors 40 via the interlayer connection conductor 44, and the other end is electrically connected to the other base portion 40 b of the other semi-annular conductor 40 via the interlayer connection conductor 46. As a result, the multiple semi-annular conductors 40, the multiple conductor patterns 42, and the multiple interlayer connection conductors 44, 46 form a helical coil conductor 34.

[0029] 5 , one end 34a of the coil conductor 34 (one base 40a of the semi-annular conductor 40 closest to the RFIC chip 36) is electrically connected to a first terminal 36a of the RFIC chip 36. The other end 34b of the coil conductor 34 (the other base 40b of the semi-annular conductor 40 farthest from the RFIC chip 36) is electrically connected to a second terminal 36b of the RFIC chip 36.

[0030] Specifically, in the first embodiment, first and second lands 54, 56 are provided on the first outermost layer 32a of the substrate 32. One end 34a of the coil conductor 34 is electrically connected to the first land 54 via the electrode 48, the interlayer connection conductor 44, a connecting conductor pattern 58 provided on the second outermost layer 32b, and an interlayer connection conductor 60. The other end 34b of the coil conductor 34 is electrically connected to the second land 56 via a folded connection conductor pattern 62 provided on the first outermost layer 32a. The folded connection conductor pattern 62 extends in the longitudinal direction (X-axis direction) through the central portion of the first outermost layer 32a in the lateral direction (Y-axis direction).

[0031] In such a wireless communication device 10, when a signal (radio wave) is received, a current flows through the antenna 20. This causes the antenna 20 to generate a magnetic field. This magnetic field generates a current in the coil conductor 34. In response to the current, the RFIC chip 36 operates and supplies a current corresponding to a transmission signal in response to the received signal to the coil conductor 34. In response to the current, the coil conductor 34 generates a magnetic field corresponding to the transmission signal. This magnetic field causes a current corresponding to the transmission signal to flow through the antenna 20, and the antenna 20 emits a transmission signal (radio wave) in response to the received signal.

[0032] Furthermore, such a wireless communication device 10 (that is, the RFID module 30) allows wireless communication over a long communication distance.

[0033] Specifically, as shown in FIG. 3 , the conductor pattern 42 of the coil conductor 34 is provided on the second outermost layer 32b of the substrate 32. Therefore, the coil opening of the coil conductor 34 defined by the semi-annular conductor 40, the interlayer connection conductor 44, the conductor pattern 42, and the interlayer connection conductor 46 is larger than when the conductor pattern 42 is provided on the first outermost layer 32a. As a result, the coil conductor 34 can generate a stronger magnetic field than when the conductor pattern 42 is provided on the first outermost layer 32a. This stronger magnetic field allows the RFID module 30 to be strongly magnetically coupled with the coil spring antenna 20, and as a result, the wireless communication device 10 can communicate wirelessly over a long communication distance.

[0034] 3 , when viewed in the longitudinal direction (X-axis direction) of the substrate 32, the distance W1 between the interlayer connection conductors 44, 46 is greater than the distance W2 between both ends of the semi-annular conductor 40 (the distance between the base portions 40 a, 40 b). Therefore, in the present embodiment, the coil opening of the coil conductor 34 is larger than when these distances W1 and W2 are the same. The reason why the width of one portion of the coil opening can be made larger than the width of the other portion is that the interlayer connection conductors 44, 46 are provided in the conductor pattern 42 on the second outermost layer 32 b, which is different from the first outermost layer 32 a on which the semi-annular conductor 40 is provided, and the distance W1 between the interlayer connection conductors 44, 46 that electrically connect the semi-annular conductor 40 and the conductor pattern 42 can be freely set within the substrate 32.

[0035] According to the first embodiment described above, in the RFID module 30 having the coil conductor 34 that magnetically couples with the coil spring-shaped antenna 20, the coil opening of the coil conductor 34 can be enlarged while maintaining the overall size of the RFID module 30 small.

[0036] Unlike the first embodiment, when the conductor pattern 42 is provided on the first outermost layer 32a, the bases 40a, 40b of the semi-annular conductor 40 are soldered to both ends of the conductor pattern 42. In this case, there is a possibility that molten solder will flow to the central portion of the conductor pattern 42 during the reflow process. If the solder hardens in the central portion of the conductor pattern 42, the coil opening of the coil conductor 34 will shrink. This problem caused by soldering can be solved by providing the multiple conductor patterns 42 on a layer (the second outermost layer 32b in the first embodiment) different from the first outermost layer 32a to which the semi-annular conductor 40 is soldered, as in the first embodiment.

[0037] Furthermore, in the case of the first embodiment, there is no significant difference in the amount of conductive material (the amount of conductor constituting the conductive pattern 42, electrodes 48, 50, etc.) in the first and second outermost layers 32 a, 32 b, so the substrate 32 is less likely to warp even when there is a temperature change.

[0038] (Embodiment 2) Embodiment 2 is an improved version of the above-described embodiment 1. Therefore, the following description of embodiment 2 will focus on the differences from embodiment 1. Note that components that are substantially the same as those of the wireless communication device 10 according to embodiment 1 are denoted by the same reference numerals.

[0039] FIG. 6 is a schematic exploded perspective view of an RFID module in a wireless communication device according to the second embodiment.

[0040] As shown in FIG. 6, an RFID module 130 of a wireless communication device according to the second embodiment includes a substrate 132, a coil conductor 34 provided on the substrate 132, and an RFIC chip 136 electrically connected to the coil conductor 34.

[0041] The coil conductor 34 also includes a plurality of semi-annular conductors 40, a plurality of conductor patterns 42, and a plurality of interlayer connection conductors 44, 46 that electrically connect these.

[0042] In the first embodiment, the first outermost layer 132a of the substrate 132 is provided with first and second lands 154, 156 electrically connected to the first and second terminals 136a, 136b of the RFIC chip 136. The first and second lands 154, 156 are arranged on the substrate 132 at a distance from each other in the short-side direction (Y-axis direction) of the substrate 132. That is, the first and second lands 154, 156 are arranged at a distance from each other in the direction perpendicular to the extension direction (X-axis direction) of the coil axis of the coil conductor 34. This prevents the first and second lands 154, 156 from blocking part of the magnetic flux generated around the coil conductor 34 in the longitudinal direction of the substrate 132 (compared to when the first and second lands 154, 156 are arranged at a distance from each other in the longitudinal direction). As a result, strong magnetic field coupling can be achieved between the coil conductor 34 and the antenna.

[0043] Unlike the second embodiment, if the first and second lands are arranged on the substrate at an interval in the longitudinal direction of the substrate, the substrate is likely to bend between the lands, and stress is likely to be concentrated on the RFIC chip 136 mounted thereon. By arranging the first and second lands 154, 156 at an interval in the lateral direction as in the second embodiment, bending of the substrate is suppressed, and stress is less likely to be concentrated on the mounted RFIC chip 136.

[0044] As in the first embodiment described above, in the second embodiment, in an RFID module 130 having a coil conductor 34 that magnetically couples with a coil spring-shaped antenna, the coil opening of the coil conductor 34 can be enlarged while maintaining the overall size of the RFID module 130 small.

[0045] (Embodiment 3) Embodiment 3 is an improved version of the above-described embodiment 1. Therefore, the following description of embodiment 3 will focus on the differences from embodiment 1. Note that components that are substantially the same as those of the wireless communication device 10 according to embodiment 1 are denoted by the same reference numerals.

[0046] Fig. 7 is a schematic exploded perspective view of an RFID module in a wireless communication device according to embodiment 3. Fig. 8 is a schematic cross-sectional view of the RFID module according to embodiment 3.

[0047] As shown in FIG. 7, an RFID module 230 of a wireless communication device according to the third embodiment includes a substrate 232, a coil conductor 34 provided on the substrate 232, and an RFIC chip 36 electrically connected to the coil conductor 34.

[0048] The coil conductor 34 also includes a plurality of semi-annular conductors 40, a plurality of conductor patterns 42, and a plurality of interlayer connection conductors 44, 46 that electrically connect these.

[0049] In the third embodiment, unlike the first embodiment described above, the folded-back connection conductor pattern 262 electrically connecting the RFIC chip 36 and the other end 34b of the coil conductor 34 (the other base portion 40b of the semi-annular conductor 40 farthest from the RFIC chip 36) is not provided on the first outermost layer 232a of the substrate 232. Instead, the folded-back connection conductor pattern 262 is provided on the second outermost layer 232b. As a result, the multiple conductor patterns 42 of the coil conductor 34 are provided on a layer 232c between the first outermost layer 232a and the second outermost layer 232b. Therefore, the substrate 232 is a multilayer substrate.

[0050] The folded-back connection conductor pattern 262 extends in the longitudinal direction (X-axis direction) in the central portion in the lateral direction (Y-axis direction) of the second outermost layer 232b.

[0051] According to this structure, as shown in Fig. 8, the corners 230a of the RFID module 230 can be chamfered. Specifically, in order to chamfer the corners 230a, the RFID module 230 can be subjected to barrel processing.

[0052] 3, in the case of the RFID module 30 of the first embodiment described above, the plurality of conductor patterns 42 of the coil conductor 34 are present on the second outermost layer 32b of the substrate 32, extending in the short-side direction (Y-axis direction). When barrel machining is performed on the RFID module 30 of the first embodiment, the corners are chamfered and the plurality of conductor patterns 42 are partially removed.

[0053] 8, the folded-back connection conductor pattern 262 is located away from the corner portion 230a on the second outermost layer 232b of the substrate 232. The folded-back connection conductor pattern 262 thus located remains intact without being scraped off even when the RFID module 230 is subjected to barrel processing.

[0054] 8, chamfering the corners 230a of the RFID module 230 allows the coil spring-shaped antenna 20 and the coil conductor 34 inside the RFID module 230 to be closer together (compared to when the corners are not chamfered). As a result, the coil conductor 34 can be strongly magnetically coupled to the antenna 20.

[0055] In the third embodiment described above, similarly to the first embodiment, in an RFID module 230 having a coil conductor 34 that magnetically couples with a coil spring-shaped antenna, the coil opening of the coil conductor 34 can be enlarged while maintaining the overall size of the RFID module 230 small.

[0056] (Fourth Embodiment) The fourth embodiment is an improved version of the first embodiment described above. Specifically, in the first embodiment described above, the conductor pattern 62 for folded connection shown in FIG. 5 does not substantially contribute to the generation of a magnetic field. In the fourth embodiment, a second coil conductor that generates a magnetic field is used instead of the conductor pattern for folded connection. Therefore, the fourth embodiment will be described focusing on this difference. Note that components that are substantially the same as the components of the wireless communication device 10 according to the first embodiment described above are assigned the same reference numerals.

[0057] FIG. 9 is a schematic exploded perspective view of an RFID module in a wireless communication device according to the fourth embodiment.

[0058] 9, an RFID module 330 of a wireless communication device according to the fourth embodiment includes a substrate 332, a coil conductor 34 provided on the substrate 332, and an RFIC chip 36 electrically connected to the coil conductor 34. Furthermore, in the case of the fourth embodiment, the RFID module 330 includes a second coil conductor 368 electrically connecting the RFIC chip 36 to the other end 34b of the coil conductor 34 (the end farther from the RFIC chip 36).

[0059] The coil conductor 34 includes a plurality of semi-annular conductors 40, a plurality of conductor patterns 42, and a plurality of interlayer connection conductors 44, 46 that electrically connect these. In the case of the fourth embodiment, the plurality of conductor patterns 42 are provided on a layer 332c between the first outermost layer 332a and the second outermost layer 332b of the substrate 332.

[0060] The second coil conductor 368 includes a plurality of second semi-annular conductors 370, a plurality of second conductor patterns 372, and a plurality of second interlayer connection conductors 374, 376, 378, 380 that electrically connect these.

[0061] The second coil conductor 368 has two ends (bases 370a, 370b) on the first outermost layer 332a of the substrate 332, spaced apart in the short-side direction (Y-axis direction) of the substrate 332. The second semi-annular conductors 370 are arranged between the semi-annular conductors 40. That is, the semi-annular conductors 40 and the second semi-annular conductors 370 are arranged on the first outermost layer 332a, alternately arranged in the long-side direction (X-axis direction) of the substrate 332. In the fourth embodiment, the second semi-annular conductors 370 have the same shape as the semi-annular conductors 40.

[0062] The second conductor patterns 372 of the second coil conductor 368 are provided on a second outermost layer 332b, which is a layer different from the first outermost layer 332a and the layer 332c on which the conductor patterns 42 of the coil conductor 334 are provided. When viewed in the thickness direction (Z-axis direction) of the substrate 332, the second conductor patterns 372 extend in a direction intersecting the conductor patterns 42 and are aligned in the longitudinal direction (X-axis direction) of the substrate 332.

[0063] The second coil conductor 368 has a plurality of second interlayer connection conductors 374, 376, 378, and 380 that electrically connect the second semi-annular conductors 370 provided on the first outermost layer 32a to the corresponding second conductor patterns 372. The second interlayer connection conductors 374 and 376 are arranged side by side in the longitudinal direction (X-axis direction) of the substrate 332 between the first outermost layer 332a and the layer 332c. The second interlayer connection conductors 378 and 380 are arranged side by side in the longitudinal direction of the substrate 332 between the layer 332c and the second outermost layer 332b.

[0064] Each of the plurality of second interlayer connection conductors 374, 378 electrically connects one end of the corresponding second conductor pattern 372 to one base portion 370 a of the second semi-annular conductor 370. Furthermore, each of the plurality of second interlayer connection conductors 376, 380 electrically connects the other end of the corresponding second conductor pattern 372 to the other base portion 370 b of the second semi-annular conductor 370. As a result, one end of each second conductor pattern 372 is electrically connected to one base portion 370 a of one of the two adjacent second semi-annular conductors 370 via the second interlayer connection conductors 374, 378, and the other end is electrically connected to the other base portion 370 b of the other second semi-annular conductor 370 via the second interlayer connection conductors 376, 380. As a result, the plurality of second semi-annular conductors 370 , the plurality of second conductor patterns 372 , and the plurality of second interlayer connection conductors 374 , 376 , 378 , 380 form a helical second coil conductor 368 .

[0065] By using such a second coil conductor 368 to electrically connect the coil conductor 334 and the RFIC chip 36 instead of the conductor pattern for folded connection, the RFID module 330 according to the fourth embodiment can generate a stronger magnetic field.

[0066] As in the above-described first embodiment, in the fourth embodiment, in an RFID module 330 having a coil conductor 34 that magnetically couples with a coil spring-shaped antenna, the coil opening of the coil conductor 34 can be enlarged while maintaining the overall size of the RFID module 330 small.

[0067] (Embodiment 5) Embodiment 5 is an improved version of the above-described embodiment 3. Therefore, the following description of embodiment 5 will focus on the differences from embodiment 3. Note that components that are substantially the same as those of wireless communication device 210 according to embodiment 3 are denoted by the same reference numerals.

[0068] FIG. 10 is a schematic exploded perspective view of an RFID module in a wireless communication device according to the fifth embodiment.

[0069] As shown in FIG. 10, an RFID module 430 of a wireless communication device according to the fifth embodiment includes a substrate 432, a coil conductor 34 provided on the substrate 432, and an RFIC chip 36 electrically connected to the coil conductor 34.

[0070] The coil conductor 34 also includes a plurality of semi-annular conductors 40, a plurality of conductor patterns 42, and a plurality of interlayer connection conductors 44, 46 that electrically connect these.

[0071] In the fifth embodiment, a conductor pattern 462 electrically connecting the RFIC chip 36 and the other end 34b of the coil conductor 34 (the other base portion 40b of the semi-annular conductor 40 farthest from the RFIC chip 36) is provided on the second outermost layer 432b. As a result, the multiple conductor patterns 42 of the coil conductor 34 are provided on the layer 232c between the first outermost layer 232a and the second outermost layer 232b.

[0072] The conductor pattern 462, which is used to adjust inductance, extends in a meandering pattern on the second outermost layer 432b. Specifically, the conductor pattern 462 extends in the longitudinal direction (X-axis direction) of the substrate 432 and includes multiple parallel straight line portions 462a, 462b, and 462c. The inductance of the conductor pattern 462 can be adjusted by adjusting the length of each of these straight line portions 462a, 462b, and 462c. This allows the resonant frequency of the RFID module 430 to be adjusted.

[0073] In the fifth embodiment as described above, similarly to the first embodiment, in an RFID module 430 having a coil conductor 34 that is magnetically coupled with a coil spring-shaped antenna, the coil opening of the coil conductor 34 can be enlarged while maintaining the overall size of the RFID module 430 small.

[0074] Although the present disclosure has been described above with reference to a number of embodiments, the present disclosure is not limited to these embodiments.

[0075] For example, in the case of the first embodiment described above, as shown in FIG. 2 , the RFIC chip 36 and the coil conductor 34 (its semi-annular conductor 40) are arranged side by side on the first outermost layer 32a of the substrate 32. However, the position of the RFIC chip 36 relative to the coil conductor 34 is not limited to this. For example, the RFIC chip 36 may be arranged inside the semi-annular conductor 40 of the coil conductor 34. Alternatively, the RFIC chip 36 may be arranged on or inside the second outermost layer 32b of the substrate 32.

[0076] In the second embodiment, the first and second lands 154, 156 are arranged at an interval in the longitudinal direction (X-axis direction) of the substrate 132. This layout of the first and second lands can also be applied to the third to fifth embodiments.

[0077] That is, various aspects of the present disclosure are as follows.

[0078] A first aspect is an RFID module having: a substrate having first and second outermost layers; a helical coil conductor extending in a first direction along the substrate; and an RFIC chip electrically connected to the coil conductor, wherein the coil conductor has both ends provided on the first outermost layer with a gap between them in a second direction intersecting the first direction, and includes: a plurality of semi-annular conductors lined up in the first direction; a plurality of conductor patterns provided on a layer different from the first outermost layer and lined up in the first direction; and a plurality of interlayer connection conductors provided between the first outermost layer and the layer on which the conductor patterns are provided and lined up in the first direction, electrically connecting each of the plurality of semi-annular conductors to the corresponding conductor pattern.

[0079] A second aspect is the RFID module of the first aspect, wherein the plurality of conductor patterns are provided on the second outermost layer.

[0080] A third aspect is the RFID module of the first aspect, wherein the plurality of conductor patterns are provided on a layer between the first outermost layer and the second outermost layer, and further comprising a folded-back connection conductor pattern that extends in the first direction through a central portion of the second outermost layer of the substrate in the second direction and electrically connects the coil conductor and the RFIC chip.

[0081] A fourth aspect is the RFID module of the first aspect, further comprising a second coil conductor, the second coil conductor having both ends provided on the first outermost layer with a gap between them in the second direction, and including a plurality of second semi-annular conductors arranged alternately with the plurality of semi-annular conductors in the first direction, a plurality of second conductor patterns arranged side by side in the first direction on a layer different from the first outermost layer and the layer on which the plurality of conductor patterns of the coil conductor are provided, and a plurality of second interlayer connection conductors arranged side by side in the first direction between the first outermost layer and the layer on which the plurality of second conductor patterns are provided, and electrically connecting the plurality of second semi-annular conductors and the corresponding second conductor patterns.

[0082] A fifth aspect is the RFID module of the first aspect, wherein the plurality of conductor patterns are provided on a layer between the first outermost layer and the second outermost layer, and further comprising an inductance-adjusting conductor pattern that extends in a meandering shape on the second outermost layer of the substrate and electrically connects the coil conductor and the RFIC chip.

[0083] A sixth aspect is the RFID module of any one of the first to fifth aspects, wherein the RFIC chip has first and second terminals, a first land provided on the first outermost layer of the substrate and electrically connecting one end of the coil conductor to the first terminal of the RFIC chip, and a second land provided on the first outermost layer of the substrate and electrically connecting the other end of the coil conductor to the second terminal of the RFIC chip, and the first and second lands are arranged on the substrate at an interval in the second direction.

[0084] A seventh aspect is the RFID module of any one of the first to sixth aspects, wherein the distance between the interlayer connection conductors is greater than the distance between both ends of the semi-annular conductor when viewed in the first direction.

[0085] An eighth aspect is the RFID module of any one of the first to seventh aspects, further comprising a protective member provided on the first outermost layer of the substrate and in which the semi-annular conductor is embedded.

[0086] A ninth aspect is a wireless communication device having a coil spring antenna and an RFID module according to any one of the first to eighth aspects, which is placed within the antenna and magnetically coupled to the antenna.

Claims

1. An RFID module comprising: a substrate having first and second outermost layers; a helical coil conductor extending in a first direction along the substrate; and an RFIC chip electrically connected to the coil conductor, wherein the coil conductor has both ends provided on the first outermost layer with a space between them in a second direction intersecting the first direction, and includes: a plurality of semi-annular conductors lined up in the first direction; a plurality of conductor patterns provided in a layer different from the first outermost layer and lined up in the first direction; and a plurality of interlayer connection conductors provided in a line in the first direction between the first outermost layer and the layer on which the conductor pattern is provided, electrically connecting each of the plurality of semi-annular conductors to the corresponding conductor pattern.

2. The RFID module according to claim 1, wherein the plurality of conductor patterns are provided on the second outermost layer.

3. The RFID module according to claim 1, wherein the plurality of conductor patterns are provided in a layer between the first outermost layer and the second outermost layer, and further comprising a folded-back connection conductor pattern that extends in the first direction through a central portion in the second direction of the second outermost layer of the substrate and electrically connects the coil conductor and the RFIC chip.

4. The RFID module according to claim 1, further comprising a second coil conductor, the second coil conductor including: a plurality of second semi-annular conductors having both ends provided on the first outermost layer with a gap between them in the second direction, and arranged alternately with the plurality of semi-annular conductors in the first direction; a plurality of second conductor patterns arranged side by side in the first direction in a layer different from the first outermost layer and the layer on which the plurality of conductor patterns of the coil conductor are provided; and a plurality of second interlayer connection conductors arranged side by side in the first direction between the first outermost layer and the layer on which the plurality of second conductor patterns are provided, electrically connecting the plurality of second semi-annular conductors and the corresponding second conductor patterns.

5. The RFID module as described in claim 1, wherein the multiple conductor patterns are provided in a layer between the first outermost layer and the second outermost layer, and further comprising an inductance adjustment conductor pattern that extends in a meandering shape through the second outermost layer of the substrate and electrically connects the coil conductor and the RFIC chip.

6. An RFID module as claimed in any one of claims 1 to 5, wherein the RFIC chip has first and second terminals, a first land provided on the first outermost layer of the substrate and electrically connecting one end of the coil conductor and the first terminal of the RFIC chip, and a second land provided on the first outermost layer of the substrate and electrically connecting the other end of the coil conductor and the second terminal of the RFIC chip, and the first and second lands are arranged on the substrate at a distance in the second direction.

7. An RFID module according to any one of claims 1 to 6, wherein the distance between the interlayer connection conductors is greater than the distance between both ends of the semi-annular conductor when viewed in the first direction.

8. The RFID module according to any one of claims 1 to 7, further comprising a protective member provided on the first outermost layer of the substrate, in which the semi-annular conductor is embedded.

9. A wireless communication device comprising: a coil spring antenna; and an RFID module according to any one of claims 1 to 8, which is disposed within the antenna and magnetically couples with the antenna.

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