RFID module

Abstract

This RFID module comprises: a substrate having a first main surface and a second main surface that face each other; an RFIC chip disposed on the first main surface of the substrate; a coil conductor having a plurality of annular electrodes; and a first pattern disposed on the substrate and electrically connecting the RFIC chip and the coil conductor. Each of the plurality of annular electrodes has a first end and a second end, and there is a gap between the first end and the second end. The gaps of the plurality of annular electrodes are respectively disposed on a straight line, and the distance of the gap from the first end to the second end is smaller than the opening diameter of the annular electrode. The plurality of annular electrodes include a first annular electrode and a second annular electrode, and the coil conductor has a second pattern that electrically connects the second end of the first annular electrode and the first end of the second annular electrode. At least a part of the first pattern is disposed inside the annular electrode.

Description

RFID module

[0001] The present invention relates to an RFID module having a substrate on which an annular electrode is mounted.

[0002] Conventionally, products are managed by attaching a radio-frequency identification (RFID) module, which is a wireless communication device, to the product. One form of RFID module is one in which a coil conductor functioning as an antenna is disposed on an insulating substrate together with an RFIC (Radio-Frequency Integrated Circuit) chip.

[0003] For example, Patent Document 1 proposes an RFID module having a coil conductor in which coil elements with legs for mounting are arranged in a line.

[0004] International Publication No. 2018 / 235714

[0005] However, since the coil conductor in the RFID module disclosed in Patent Document 1 is disposed on a substrate, the diameter of the coil opening is reduced by the size of the substrate within the external size of the RFID module. Improving the antenna characteristics results in an increase in the size of the RFID module.

[0006] An object of the present invention is to provide an RFID module having improved antenna characteristics relative to its external size.

[0007] An RFID module according to one aspect of the present invention includes a substrate having a first and second main surface facing each other, an RFIC chip disposed on the first main surface of the substrate, a coil conductor having a plurality of annular electrodes, and a first pattern disposed on the substrate and electrically connecting the RFIC chip and the coil conductor. Each of the plurality of annular electrodes has a first end and a second end, and a gap exists between the first end and the second end. The gaps between the plurality of annular electrodes are arranged on a straight line, and the distance between the first end and the second end is smaller than the diameter of the opening of the annular electrode. The plurality of annular electrodes includes a first annular electrode and a second annular electrode, and the coil conductor has a second pattern electrically connecting the second end of the first annular electrode and the first end of the second annular electrode. At least a portion of the first pattern is disposed inside the annular electrodes.

[0008] According to the present invention, it is possible to provide an RFID module having improved antenna characteristics relative to its external size.

[0009] a perspective view of an RFID module according to a first embodiment; a perspective view of an RFID module from which the resin layer has been removed; an exploded perspective view of a coil assembly from which the substrate has been disassembled; a side view of an RFID module from which the substrate has been removed, viewed along the longitudinal direction; a side view of a coil conductor and a substrate, viewed along the longitudinal direction; a plan view showing wiring patterns on each base layer of the substrate; a perspective view of an RFID module according to a modified example of the first embodiment, from which the resin layer has been removed; a plan view of a resin block; a perspective view of an RFID module according to a second embodiment, from which the resin layer has been removed; a perspective view of an RFID module according to a modified example of the second embodiment, from which the resin layer has been removed; a perspective view showing a manufacturing process of an RFID module according to a modified example of the second embodiment; a side view of a coil conductor and a substrate, viewed along the longitudinal direction,

[0010] Each of the embodiments described below shows a specific example of the present invention, and the present invention is not limited to this configuration. Furthermore, the numerical values, shapes, configurations, steps, and step orders specifically shown in the following embodiments are examples and do not limit the present invention. Among the components in the following embodiments, components that are not described in the independent claims that represent the highest concepts are described as optional components. Furthermore, in all embodiments, the configurations in each modification are the same, and the configurations described in each modification may be combined with each other.

[0011] (Embodiment 1) Next, the schematic configuration of an RFID module 1 according to embodiment 1 will be described with reference to FIGS. 1 to 3. FIG. 1 is an overall perspective view of the RFID module 1 according to embodiment 1. FIG. 2 is a perspective view of the RFID module 1 with the resin layer 9 removed. FIG. 3 is an exploded perspective view of the substrate 3 disassembled from the coil assembly 6. In the figures, the X-Y-Z coordinate system is used to facilitate understanding of the invention and does not limit the invention. The X-axis direction indicates the longitudinal direction of the RFID module 1, the Y-axis direction indicates the depth direction, and the Z-axis direction indicates the thickness direction. The X, Y, and Z directions are perpendicular to one another. In addition, in the description of the embodiment, the positive direction of the Z axis is the upward direction, and the negative direction of the Z axis is the downward direction.

[0012] The RFID module 1 of the embodiment includes a substrate 3, a coil assembly 6 connected to a first main surface 4 and a second main surface 5 of the substrate 3, an RFIC chip 7 arranged on the first main surface 4 of the substrate 3, and a resin layer 9 that seals the substrate 3, the coil assembly 6, and the RFIC chip 7.

[0013] The substrate 3 is a double-sided substrate, and a first main surface 4 and a second main surface 5 of the substrate 3 face each other. The substrate 3 is insulating and is, for example, a glass epoxy substrate or a ceramic substrate. The RFIC chip 7 not only outputs information (e.g., ID information or security information) stored in advance in the chip, but also includes chips that have a built-in sensor for measuring environmental information (e.g., temperature, humidity, pressure) and have the function of outputting the acquired information together with the pre-stored information.

[0014] The resin layer 9 is a molding material that seals the substrate 3, the RFIC chip 7, and the coil conductor 19. The resin layer 9 is formed of a general sealing resin such as an epoxy resin.

[0015] The coil assembly 6 includes a plurality of annular electrodes 11. The annular electrodes 11 are made of a metal conductor and are manufactured, for example, by stamping a metal plate. See FIG. 4 . FIG. 4 is a side view of the RFID module 1 viewed along the longitudinal direction. Note that the substrate 3 is omitted from FIG. 4 for ease of understanding. The annular electrodes 11 have a first end 13, which is one end, a second end 15, which is the other end, and a gap 17 between the first end 13 and the second end 15. The annular electrodes 11 have, for example, a ring-like shape with a portion missing, and extend continuously from the first end 13 to the second end 15. The distance Wa of the gap 17 from the first end 13 to the second end 15 is smaller than the opening diameter Ra of the annular electrode 11, for example, smaller than 1 / 8 of the opening diameter Ra.

[0016] As shown in FIG. 3 , the annular electrodes 11 are arranged such that the gaps 17 of the annular electrodes 11 are aligned in a straight line. Therefore, as shown in FIG. 5 , the substrate 3 can be placed in the gaps 17 of the annular electrodes 11. The first end 13 of the annular electrode 11 is closer to the first main surface 4 than to the second main surface 5 of the substrate 3, and the second end 15 of the annular electrode 11 is closer to the second main surface 5 than to the first main surface 4 of the substrate 3. For example, the substrate 3 is inserted vertically into the gaps 17 and sandwiched between the first ends 13 and second ends 15 of the annular electrodes 11. In the first embodiment, the first end 13 of each annular electrode 11 is connected to the first main surface 4 of the substrate 3, and the second end 15 is connected to the second main surface 5 of the substrate 3. At least a portion of the substrate 3 is positioned inside the inner periphery 12 b of the annular electrode 11.

[0017] Each of the multiple annular electrodes 11 of the coil assembly 6 is connected to a conductor pattern arranged on the substrate 3 to form a single coil conductor 19, which functions as an antenna. The communication frequency band in the RFID module 1 of this embodiment is, for example, the UHF band of 860 MHz to 960 MHz. The number and dimensions of the annular electrodes 11 may be changed according to the communication characteristics.

[0018] Next, the substrate 3 will be described with reference to FIG. 6 . FIG. 6 is a plan view showing the wiring patterns on each base layer of the substrate 3. FIG. 6( a) is a perspective plan view of the substrate 3 seen from the first main surface side, showing the conductor pattern on the second main surface 5 of the substrate 3. FIG. 6( b) is a perspective plan view of the substrate 3 seen from the first main surface side, showing the conductor pattern on the third main surface. FIG. 6( c) is a perspective plan view of the substrate 3 seen from the first main surface side, showing the conductor pattern on the third main surface. In FIG. 6 , the dashed line indicates a connection by the ring-shaped electrode 11, and the dashed two-dot line indicates a through-hole connection.

[0019] The substrate 3 is a laminated substrate and has a first substrate layer 21, a second substrate layer 23, and a third substrate layer 25. In the substrate 3, the third substrate layer 25 serves as a bottom substrate, the second substrate layer 23 is laminated on the third substrate layer 25, and the first substrate layer 21 is further laminated on the second substrate layer 23. The first substrate layer 21 to the third substrate layer 25 are each insulating, and are, for example, a glass epoxy substrate or a ceramic substrate.

[0020] The outer main surface of the first base material layer 21 is the first main surface 4 of the substrate 3. The inner main surface of the first base material layer 21 is in contact with a main surface 29 of the second base material layer 23 on the RFIC chip 7 side. The main surface of the second base material layer 23 opposite to the main surface 29 is in contact with an inner main surface 33 of the third base material layer 25. The outer main surface, which is the bottom surface of the third base material layer 25, is the second main surface 5 of the substrate 3.

[0021] 6( c), the RFIC chip 7 has a first terminal 35 and a second terminal 37, which are input / output terminals. A first conductor pattern 39, a plurality of second conductor patterns 41, and interlayer connection conductors 43 and 45 that penetrate the inside of the substrate 3 are arranged on the first main surface 4 of the first base layer 21.

[0022] The first conductor pattern 39 is a pattern for electrically connecting the RFIC chip 7 and the annular electrode 11. The second conductor pattern 41 is a part of a pattern for electrically connecting the two annular electrodes 11. One end (upper end) of the second conductor pattern 41 is connected to the first end 13 of the annular electrode 11 via a solder electrode.

[0023] 6(b), interlayer connection conductors 45 and 47 that penetrate the inside of the substrate 3 and a third conductor pattern 49 that corresponds to the first pattern are arranged on the main surface 29 of the second base layer 23. The interlayer connection conductor 47 and the third conductor pattern 49 are part of a pattern for connecting the RFIC chip 7 to the annular electrode 11 that is farthest from the RFIC chip 7.

[0024] 6( c), a plurality of fourth conductor patterns 51, a fifth conductor pattern 53, and interlayer connection conductors 45 and 47 that penetrate the inside of the substrate 3 are arranged on the second main surface 5 that faces the main surface 33 of the second base layer 23. The fourth conductor pattern 51 is part of a pattern for electrically connecting the two annular electrodes 11.

[0025] As shown in Figure 6, one end of the first conductor pattern 39 is electrically connected to the second terminal 37 of the RFIC chip 7 via solder, and the other end of the first conductor pattern 39 is electrically connected to the first end 13 of the annular electrode 11 closest to the RFIC chip 7 via solder.

[0026] The number of annular electrodes 11 included in the coil assembly 6 is defined as N. N is an integer equal to or greater than 2. The N annular electrodes 11 are arranged on one side, for example, as shown in FIG. 3 , from the RFIC chip 7 side, as annular electrode 11a1, annular electrode 11a2, ..., annular electrode 11an. Similarly, N-1 second conductor patterns 41 are arranged on the first main surface 4 of the first base layer 21, and from the RFIC chip 7 side, as second conductor pattern 41a1, second conductor pattern 41a2, ..., second conductor pattern 41an-1. Similarly, N-1 fourth conductor patterns 51 are arranged on the second main surface 5 of the third base layer 25, and from the RFIC chip 7 side, as fourth conductor pattern 51a1, fourth conductor pattern 51a2, ..., fourth conductor pattern 51an-1.

[0027] The interlayer connection conductor 43 is a conductive via that connects the first terminal 35 of the RFIC chip 7 on the first base material layer 21 to the third conductor pattern 49 on the second base material layer 23. The interlayer connection conductor 45 is a conductive via that connects the second conductor pattern 41 on the first base material layer 21 to the fourth conductor pattern 51 on the third base material layer 25. The interlayer connection conductor 47 is a conductive via that connects the third conductor pattern 49 on the second base material layer 23 to the fifth conductor pattern 53 on the third base material layer 25. The interlayer connection conductors 43, 45, 47 are, for example, conductors formed by solidifying (metallizing) a conductive paste that has been filled in a hole provided in the insulating substrate 3, but may also be plated through holes.

[0028] The other end of the first conductor pattern 39 on the first base layer 21 is electrically connected via solder to a first end 13 of the annular electrode 11a1 closest to the RFIC chip 7. The second end 15 of the annular electrode 11a1 is electrically connected via solder to one end (upper end) of the fourth conductor pattern 51a1 on the third base layer 25. The other end (lower end) of the fourth conductor pattern 51a1 on the third base layer 25 is electrically connected to the other end (lower end) of the second conductor pattern 41a1 on the first base layer 21 via an interlayer connection conductor 45.

[0029] One end (upper end) of the second conductor pattern 41a1 on the first base layer 21 is electrically connected to the first end 13 of the annular electrode 11a2 via solder. The second end 15 of the annular electrode 11a2 is electrically connected to one end (upper end) of the fourth conductor pattern 51a2 on the third base layer 25 via solder. The other end (lower end) of the fourth conductor pattern 51a2 on the third base layer 25 is electrically connected to the other end (lower end) of the second conductor pattern 41a2 on the first base layer 21 via the interlayer connection conductor 45. In this way, the annular electrodes 11 are electrically connected in sequence in the X-axis direction. The coil conductor 19 includes the annular electrode 11, the fourth conductor pattern 51, the interlayer connection conductor 43, and the fifth conductor pattern 53, and functions as a single coil.

[0030] The annular electrodes 11 are electrically connected in sequence, and the second end 15 of the annular electrode 11an-1 is electrically connected via solder to one end (upper end) of the fourth conductor pattern 51an-1 on the third base layer 25. The other end (lower end) of the fourth conductor pattern 51an-1 on the third base layer 25 is electrically connected to the other end (lower end) of the second conductor pattern 41an-1 on the first base layer 21 via an interlayer connection conductor 45. One end (upper end) of the second conductor pattern 41an-1 on the first base layer 21 is electrically connected to the first end 13 of the annular electrode 11an via solder. The second end 15 of the annular electrode 11an is electrically connected to the fifth conductor pattern 53 on the third base layer 25 via solder.

[0031] The fifth conductor pattern 53 on the third base layer 25 is electrically connected to one end of the third conductor pattern 49 on the second base layer 23 via the interlayer connection conductor 47. The third conductor pattern 49 extends from one end to the other end in the X-axis direction on the third base layer 25, and the other end of the third conductor pattern 49 is electrically connected to the first terminal 35 of the RFIC chip 7 on the first base layer 21 via the interlayer connection conductor 43. In this way, an electrical connection is formed from the second terminal 37 of the RFIC chip 7 through the coil conductor 19, the interlayer connection conductor 47, the third conductor pattern 49, and the interlayer connection conductor 43 to the first terminal 35 of the RFIC chip 7. As shown in FIG. 5 , when the coil conductor 19 is viewed in the longitudinal direction or in a cross-sectional view perpendicular to the central axis of the coil conductor 19, at least a portion of the third conductor pattern 49 is disposed inside the annular electrode 11. Here, the inside of the annular electrode 11 refers to the inside of the area enclosed by the outer periphery 12a of the annular electrode 11 and the line connecting the outer periphery 12a side of the first end 13 of the annular electrode 11 and the outer periphery 12a side of the second end 15.

[0032] An LC parallel resonant circuit is configured within the RFID module 1 and is matched to radio waves of the communication frequency, so that when the coil conductor 19 receives radio waves of the communication frequency, a current flows through the RFIC chip 7 .

[0033] The first conductor pattern 39, the second conductor pattern 41, the third conductor pattern 49, the fourth conductor pattern 51, and the fifth conductor pattern 53 are each a conductor, and are formed by patterning copper foil by photolithography, for example.

[0034] As described above, the RFID module 1 of the first embodiment includes the substrate 3 having the first and second principal surfaces 4 and 5 facing each other, the RFIC chip 7 disposed on the first principal surface 4 of the substrate 3, the coil conductor 19 having a plurality of annular electrodes 11, and the third conductor pattern 49 disposed on the substrate 3 as a first pattern electrically connecting the RFIC chip 7 and the coil conductor 19. Each of the plurality of annular electrodes 11 has a first end 13 and a second end 15. A gap 17 exists between the first end 13 and the second end 15, and the gaps 17 between the plurality of annular electrodes 11 are arranged on a straight line. The distance Wa of the gap 17 from the first end 13 to the second end 15 is smaller than the opening diameter Ra of the annular electrode 11. The plurality of annular electrodes 11 includes an annular electrode 11a1 and an annular electrode 11a2. The coil conductor 19 has a fourth conductor pattern 51, an interlayer connection conductor 45, and a second conductor pattern 41 as a second pattern that electrically connects the second end 15 of the annular electrode 11a1 and the first end 13 of the annular electrode 11a2. At least a portion of the third conductor pattern 49 is disposed inside the annular electrode 11a1.

[0035] According to the RFID module 1 having this configuration, at least a portion of the third conductor pattern 49 is disposed inside the annular electrode 11, so that the opening diameter of the annular electrode 11, which functions as a coil, can be made larger relative to the external size of the RFID module 1. This allows for a longer communication distance and improved antenna characteristics relative to the external size of the RFID module 1. Furthermore, because at least a portion of the third conductor pattern 49, which electrically connects the RFIC chip 7 and the coil conductor 19, is disposed inside the annular electrode 11, attenuation of the magnetic field generated from the annular electrode 11 by the third conductor pattern 49 can be reduced.

[0036] Furthermore, the width Wb of the substrate 3 is smaller than the opening diameter Ra of the annular electrode 11. In other words, the opening diameter Ra of the annular electrode 11 can be made larger than the width Wb of the substrate 3, thereby improving the communication characteristics of the RFID module 1.

[0037] Furthermore, if the entire third conductor pattern 49 is arranged inside the annular electrode 11, the attenuation of the magnetic field generated from the annular electrode 11 by the third conductor pattern 49 can be greatly reduced, thereby further improving the communication characteristics of the RFID module 1.

[0038] Furthermore, the first main surface 4 and the second main surface 5 of the substrate 3 intersect with the direction in which the first end 13 and the second end 15 of the annular electrode 11 face each other. By arranging the substrate 3 in this manner, the opening diameter Ra of the annular electrode 11 can be made larger than the outer size of the RFID module 1.

[0039] Next, an RFID module 1A, which is a modification of the first embodiment, will be described with reference to FIG. 7 . FIG. 7 is a perspective view of the RFID module 1A of the modification of the first embodiment with the resin layer 9 removed. In the RFID module 1A of the modification, the multiple annular electrodes 11 are integrated with a resin block 61 to maintain the pitch of each annular electrode 11. Hardening the annular electrodes 11 with resin before attaching the electrodes to the substrate 3 facilitates attachment to the substrate 3. The resin block 61 may harden only a portion of the annular electrodes 11, or may harden most or all of the annular electrodes 11 while maintaining the gaps 17 between the multiple annular electrodes 11. The resin block 61 protects the annular electrodes 11.

[0040] The resin block 61 may be formed by molding the annular electrodes 11 arranged at a predetermined pitch, or the annular electrodes 11 may be fitted into a flexible resin block 61A as shown in Fig. 8. The resin block 61A has holes 63 arranged at a predetermined pitch, into which the annular electrodes 11A are inserted. The holes 63 have notches 65 formed therein that connect to the outer periphery of the resin block 61A. The resin block 61A may also be provided with a recess 66 that supports the lower end of the substrate 3, thereby improving the positioning accuracy of the substrate 3.

[0041] Second Embodiment Next, an RFID module 1B according to a second embodiment will be described with reference to Fig. 9. Fig. 9 is a perspective view showing an outline of an RFID module 1B according to the second embodiment.

[0042] While the coil conductor 19 of the RFID module 1 in embodiment 1 was substantially circular, the annular electrode 11B of the coil conductor 19B of the RFID module 1B in embodiment 2 has a rectangular or polygonal shape. Except for this point and points described below, the RFID module 1B in embodiment 2 and the RFID module 1 in embodiment 1 have the same configuration, and therefore a description of the common configuration will be omitted.

[0043] 9 has a substantially octagonal shape, with a gap 17 on one side of the octagon. The annular electrode 11B may be substantially hexagonal or may be substantially polygonal with 10 or more sides.

[0044] Next, an RFID module 1C that is a modification of the second embodiment will be described with reference to Fig. 10. In the annular electrode 11C of the coil conductor 19C of the RFID module 1C, the first end 13C and the second end 15C may each protrude outward in the direction of the opening diameter along the substrate 3. In this way, the first end 13C and the second end 15C of the annular electrode 11B have a shape that protrudes outward, thereby increasing the attachment area with the substrate 3 and improving the attachment strength.

[0045] Such an annular electrode 11C can be manufactured by the following method. As shown in FIG. 11 , an annular electrode 11C is formed having protrusions 67 protruding outward from the first end 13C and the second end 15C of the annular electrode 11B with an opening diameter Ra. Multiple annular electrodes 11C may be integrated into a resin block 61. When inserting a substrate 3 into the gap 17 of the annular electrode 11C, the protrusions 67 can be opened with a tool to allow the substrate 3 to enter the widened gap 17, thereby reducing the risk of solder paste applied to the second conductor pattern 41 and the fourth conductor pattern 51 of the substrate 3 coming into contact with and flowing to other parts of the substrate 3. Furthermore, when transporting the coil conductor 19C, the protrusions 67 can be grasped to transport the coil conductor 19C, allowing the annular electrode 11C to be transported without being damaged.

[0046] After the first end 13 and the second end 15 of the annular electrode 11C are attached to the substrate 3, the protrusion 67 can be cut to form an annular electrode 11C having a first end 13C and a second end 15C protruding outward as shown in Figure 10.

[0047] The extending direction of the protrusion 67 is not limited to a direction parallel to the first main surface 4 and the second main surface 5 of the substrate 3. As shown in Fig. 12, the extending direction of the protrusion 67 may be a direction intersecting the first main surface 4 and the second main surface 5 of the substrate 3. In this case, the connecting end surfaces of the first end 13 and the second end 15 of the annular electrode 11C to the substrate 3 are inclined with respect to the first main surface 4 and the second main surface 5 of the substrate 3. This increases the attachment area between the first end 13 and the second end 15 of the annular electrode 11C and the substrate 3, thereby improving the attachment strength between the annular electrode 11C and the substrate 3.

[0048] (Embodiment 3) Next, an RFID module 1D of embodiment 3 will be described with reference to Figs. 13 and 14. Fig. 13 is a perspective view of an RFID module with the resin layer removed according to embodiment 3. Fig. 14 is a plan view showing wiring patterns on each main surface of a substrate 3 according to embodiment 3. Fig. 14(a) is a plan view of the substrate 3 viewed from the first main surface 4 side, showing the conductor pattern on the first main surface 4 of the substrate 3. Fig. 14(b) is a perspective plan view of the substrate 3 viewed from the first main surface 4 side, showing the conductor pattern on the second main surface 5.

[0049] Whereas the substrate 3 of the RFID module 1 in the first embodiment is arranged to fit into the gap 17 of the annular electrode 11, the substrate 3 of the RFID module 1D in the third embodiment is arranged entirely inside the gap 17, i.e., inside the annular electrode 11D. Other than this and the points described below, the configuration of the RFID module 1D in the third embodiment is the same as that of the RFID module 1 in the first embodiment, and therefore a description of the common configuration will be omitted.

[0050] The RFIC chip 7 is disposed on the second main surface 5 of the substrate 3D. A second terminal 37 of the RFIC chip 7 is electrically connected to a first conductor pattern 39D disposed on the first main surface 4 of the substrate 3D via an interlayer connection conductor. The first conductor pattern 39D is also electrically connected to the second end 15 of the annular electrode 11Da1.

[0051] A second conductor pattern 41D electrically connecting the first end 13 of the annular electrode 11Dak and the second end 15 of the adjacent annular electrode 11Dak+1 is arranged on the first main surface 4 of the substrate 3D. k is an integer greater than or equal to 1 and less than or equal to N-1. The first end 13 and second end 15 of the annular electrode 11D are attached to the first main surface 4 of the substrate 3D. The first end 13 of the annular electrode 11Da1 is electrically connected to one end of the second conductor pattern 41Da1 via solder. The other end of the second conductor pattern 41Da1 is electrically connected to the second end 15 of the annular electrode 11Da2 via solder.

[0052] The plurality of annular electrodes 11D are electrically connected in sequence via the second conductor pattern 41D, and the second end 15 of the annular electrode 11Dn is electrically connected to one end of the second conductor pattern 41Dan-1 via solder, and the first end 13 of the annular electrode 11Dn is electrically connected to the fifth conductor pattern 53D via solder.

[0053] The fifth conductor pattern 53D is electrically connected to one end of the third conductor pattern 49D by an interlayer connection conductor. The other end of the third conductor pattern 49D is electrically connected to the first terminal 35 of the RFIC chip 7.

[0054] According to the RFID module 1D of the third embodiment, in addition to the effects of the RFID module 1 of the first embodiment, the substrate 3D is entirely disposed inside the annular electrode 11D, so that the substrate 3D is protected from impacts and the like.

[0055] Fourth Embodiment Next, an RFID module 1E according to a fourth embodiment will be described with reference to Fig. 15. Fig. 15 is a perspective view of an RFID module 1E according to the fourth embodiment.

[0056] Whereas the annular electrode 11D of the RFID module 1D in the third embodiment is formed by punching out a metal plate, the annular electrode 11E of the RFID module 1E in the fourth embodiment is formed by rolling a pattern electrode that is formed in a linear shape on the flexible substrate 71. Other than this point and the points that will be described below, the RFID module 1D in the third embodiment and the RFID module 1E in the fourth embodiment are identical in configuration, and therefore a description of the common configuration will be omitted.

[0057] By using a heat-resistant resin material as the base material for the flexible substrate 71, the substrate 3D and the flexible substrate 71 can be attached using a reflow oven. By using a pattern electrode formed on the flexible substrate 71 as the annular electrode 11E, costs can be significantly reduced. Furthermore, by rolling the flexible substrate 71 so that the annular electrode 11E is on the inside and attaching it to the substrate 3D, the annular electrode 11E can be protected, and the resin layer 9 can be omitted.

[0058] 16 is a perspective view of an RFID module 1F according to a modification of the fourth embodiment. The RFID module 1F further includes a core material 73 in addition to the components of the RFID module 1E of the fourth embodiment. The core material 73 is made of, for example, a resin material. The core material 73 has a generally cylindrical shape, and the flexible substrate 71 is wound around and fixed to the core material 73, thereby increasing the strength of the RFID module 1F. The substrate 3D may be attached to the core material 73 or may be formed within the core material 73.

[0059] Although the present invention has been described in various embodiments with a certain degree of detail, the disclosure of these embodiments may vary in structural details, and variations in the combination and order of elements in the various embodiments may be realized without departing from the scope and spirit of the invention as claimed.

[0060] (Summary of the Embodiment) An RFID module according to a first aspect of the present invention includes a substrate having a first main surface and a second main surface facing each other, an RFIC chip disposed on the first main surface of the substrate, a coil conductor having a plurality of annular electrodes, and a first pattern disposed on the substrate and electrically connecting the RFIC chip and the coil conductor. Each of the plurality of annular electrodes has a first end and a second end, and a gap exists between the first end and the second end. The gaps between the plurality of annular electrodes are arranged on a straight line, and the distance between the first end and the second end is smaller than the diameter of the opening of the annular electrode. The plurality of annular electrodes includes a first annular electrode and a second annular electrode, and the coil conductor has a second pattern electrically connecting the second end of the first annular electrode and the first end of the second annular electrode. At least a portion of the first pattern is disposed inside the annular electrodes.

[0061] According to this aspect of the RFID module, since at least a portion of the first pattern is disposed inside the annular electrode, the opening diameter of the annular electrode that functions as a coil can be made larger relative to the external size of the RFID module. Therefore, the communication distance can be increased relative to the external size of the RFID module. Furthermore, since at least a portion of the first pattern is disposed inside the annular electrode, attenuation of the magnetic field generated from the annular electrode by the first pattern of the RFID module can be reduced.

[0062] According to a second aspect, in the RFID module of the first aspect, the width of the substrate is smaller than the diameter of the opening of the annular electrode.

[0063] According to a third aspect, in the RFID module of the first or second aspect, the first pattern connects the RFIC chip to the annular electrode that is disposed farthest from the RFIC chip.

[0064] According to a fourth aspect, in the RFID module of any one of the first to third aspects, the first pattern is entirely disposed inside the annular electrode.

[0065] According to a fifth aspect, in the RFID module of any one of the first to fourth aspects, the first and second main surfaces of the substrate intersect with the direction in which the first end and second end of the annular electrode face each other.

[0066] According to a sixth aspect, in the RFID module of the fifth aspect, the first end of the annular electrode is closer to the first main surface of the substrate than the second main surface of the substrate, and the second end of the annular electrode is closer to the second main surface of the substrate than the first main surface of the substrate.

[0067] According to a seventh aspect, in the RFID module of the fifth or sixth aspect, the first end and the second end of the annular electrode are inclined with respect to the first main surface and the second main surface of the substrate, respectively.

[0068] According to an eighth aspect, in the RFID module of any one of the first to fourth aspects, the plurality of annular electrodes are pattern electrodes arranged on a flexible substrate.

[0069] According to a ninth aspect, in the RFID module of the eighth aspect, the second pattern is arranged on the first main surface or the second main surface of the substrate, and the first end and the second end of the annular electrode are arranged on either the first main surface or the second main surface of the substrate.

[0070] According to a tenth aspect, in the RFID module of the eighth or ninth aspect, a core material made of resin is provided, and the flexible substrate is wound around the core material.

[0071] REFERENCE SIGNS LIST 1, 1A, 1B, 1C, 1D, 1E, 1F RFID module 3, 3D Substrate 4 First main surface 5 Second main surface 6 Coil assembly 7 RFIC chip 9 Resin layer 11, 11B, 11C, 11D Ring-shaped electrode 13 First end 15 Second end 17 Gap 19, 19B, 19C, 19D Coil conductor 21 First base material layer 23 Second base material layer 25 Third base material layer 29 Main surface 33 Main surface 35 First terminal 37 Second terminal 39 First conductor pattern 41 Second conductor pattern 43, 45, 47 Interlayer connection conductor 49, 49D Third conductor pattern 51 Fourth conductor pattern 53, 53D Fifth conductor pattern 61, 61A Resin block 63 Hole 65 Notch 67 Protrusion 71 Flexible substrate 73 Core material Wa Distance Ra Opening diameter

Claims

1. A substrate having a first main surface and a second main surface facing each other, An RFIC chip disposed on the first main surface of the substrate, A coil conductor having multiple annular electrodes, The substrate comprises a first pattern arranged on the substrate and electrically connecting the RFIC chip and the coil conductor, Each of the aforementioned plurality of annular electrodes has a first end and a second end. A gap exists between the first end and the second end. The gaps between the plurality of annular electrodes are each arranged in a straight line. The distance of the gap from the first end to the second end is smaller than the aperture diameter of the annular electrode. The plurality of annular electrodes include a first annular electrode and a second annular electrode, The coil conductor has a second pattern that electrically connects the second end of the first annular electrode and the first end of the second annular electrode. At least a portion of the first pattern is located inside the annular electrode. RFID module.

2. The width of the substrate is smaller than the aperture diameter of the annular electrode. The RFID module according to claim 1.

3. The first pattern connects the annular electrode furthest from the RFIC chip to the RFIC chip. The RFID module according to claim 1.

4. All of the first pattern is arranged inside the annular electrode. The RFID module according to claim 1.

5. The first and second main surfaces of the substrate intersect in the direction in which the first and second ends of the annular electrode face each other. The RFID module according to claim 1.

6. The first end of the annular electrode is closer to the first main surface of the substrate than to the second main surface. The second end of the annular electrode is closer to the second main surface of the substrate than to the first main surface. The RFID module according to claim 5.

7. The first and second ends of the annular electrode are inclined with respect to the first and second main surfaces of the substrate, respectively. The RFID module according to claim 5 or 6.

8. The aforementioned plurality of annular electrodes are pattern electrodes arranged on a flexible substrate. The RFID module according to claim 1.

9. The second pattern is arranged on the first main surface or the second main surface of the substrate. The first and second ends of the annular electrode are positioned on either the first main surface or the second main surface of the substrate. The RFID module according to claim 8.

10. Equipped with a resin core, The flexible substrate is wound around the core material. The RFID module according to claim 8 or 9.