RFID Module

Abstract

In the present invention, an RFID module comprises: a substrate; first and second electrodes that are positioned on the substrate; a coil element, of which one end is connected to the first electrode and the other end is connected to the second electrode; an RFIC chip via which the first electrode and the second electrode are electrically connected; and a first insulation layer that covers the RFIC chip. The coil element is wound around the substrate, at least a portion of the coil element being exposed outside the first insulation layer.

Description

[Technical Field]

[0001] The present invention relates to an RFID module having a substrate on which a coil conductor is mounted. [Background technology]

[0002] Conventionally, products are managed by attaching an RFID (Radio-Frequency Identification) module, which is a wireless communication device, to the product. One form of RFID module is one in which a coil conductor that functions as an antenna is arranged 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018-235714 Summary of the Invention [Problem to be solved by the invention]

[0005] The coil conductor in the RFID module disclosed in Patent Document 1 is disposed inside a mold, and therefore the opening of the coil conductor is narrow, resulting in a decrease in the communication characteristics as an antenna.

[0006] An object of the present invention is to provide an RFID module with improved communication characteristics. [Means for solving the problem]

[0007] An RFID module according to one embodiment of the present invention includes a substrate, a first electrode and a second electrode disposed on the substrate, a coil element connected at one end to the first electrode and at the other end to the second electrode, an RFIC chip electrically connected at one end to the first electrode and at the other end to the second electrode, and a first insulating layer covering the RFIC chip. The coil element wraps around the substrate, and at least a portion of the coil element is exposed to the outside of the first insulating layer. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an RFID module with improved communication characteristics. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an outline of an RFID module according to a first embodiment; [Figure 2] See-through side view of RFID module [Figure 3] A vertical cross section of an RFID module without the coil element [Figure 4] FIG. 1 is a plan view showing electrodes arranged on a substrate; [Figure 5] An explanatory diagram explaining the opening area [Figure 6] FIG. 1 is an explanatory diagram illustrating a method for forming a resist layer. [Figure 7] FIG. 10 is a plan view showing an outline of an RFID module according to a second embodiment. [Figure 8] Cross section of line AA in Figure 7 [Figure 9] FIG. 10 is a longitudinal sectional view of an RFID module according to a third embodiment. [Figure 10] FIG. 10 is a plan view showing electrodes arranged on a substrate according to a third embodiment. [Figure 11] 10 is a side view of the RFID module of the fourth embodiment. [Figure 12] FIG. 10 is a longitudinal sectional view of an RFID module according to a fourth embodiment. [Figure 13] Equivalent circuit diagram of the RFID module of embodiment 4 DETAILED DESCRIPTION OF THE INVENTION

[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, a schematic configuration of an RFID module 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of the RFID module 1 according to the first embodiment. FIG. 2 is a perspective side view of the RFID module 1. FIG. 3 is a longitudinal sectional view of the RFID module 1 from which the coil element 6 is omitted. In the figures, the XYZ 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 (width) direction, and the Z-axis direction indicates the thickness direction. The X, Y, and Z directions are perpendicular to one another. In the embodiments, the positive direction of the Z-axis is defined as the upward direction, and the negative direction of the Z-axis is defined as the downward direction.

[0012] The RFID module 1 of the embodiment includes a substrate 3, a coil element 6 and an RFIC chip 7 arranged on a first main surface 4 which is the upper surface of the substrate 3, and a resin layer 10 which seals the coil element 6 and the RFIC chip 7. The RFID module 1 is, for example, a cube or a rectangular parallelepiped.

[0013] The RFIC chip 7 has a first terminal 8 and a second terminal 9 which are input / output terminals. The substrate 3 in the first embodiment is a double-sided substrate, and a second main surface 5 which is the lower surface of the substrate 3 and a first main surface 4 face each other. The substrate 3 is insulating and is, for example, a glass epoxy substrate or a ceramic substrate.

[0014] A resist layer 17 is laminated on the second main surface 5 of the substrate 3. The resist layer 17 covers and protects a first electrode 29 and a second electrode 31, which will be described later, disposed on the second main surface 5. The resist layer 17 is, for example, an insulating resin layer.

[0015] 1 and 2, the coil element 6 is configured by winding a conducting wire 41 multiple times around a winding axis Wa, and the coil element 6 functions as an antenna. The communication frequency band in the RFID module 1 of the embodiment is, for example, the UHF band of 860 MHz to 960 MHz. The number of turns and dimensions of the coil element 6 may be changed according to the communication characteristics.

[0016] The coil element 6 has a first end 44 connected to the first electrode 29 and a second end 45 connected to the second electrode 31. The coil element 6 is an air-core coil having a cavity inside. The winding pitch of the conductor 41 is larger than the wire diameter of the conductor 41. As a result, the coil element 6 has gaps between adjacent wound conductors 41, which makes it easier for the magnetic field generated by the coil element 6 to be released to the outside and facilitates magnetic field coupling, thereby improving communication characteristics.

[0017] The conductor 41 may have a conductive core wire and an insulating film covering the outer periphery of the core wire, or may consist of only the core wire. If the conductor 41 has an insulating film, the insulating film is removed from the joints between the coil element 6 and the first electrode 29 and the second electrode 31, respectively, and the core wire is joined to each electrode. The conductor 41 and the first electrode 29 and the second electrode 31 are fixed by heating or laser irradiation. After connecting the conductor 41 to either the first electrode 29 or the second electrode 31, the coil element 6 is wound around the substrate 3 and the resin layer 10 and then connected to the other of the first electrode 29 and the second electrode 31. If the conductor 41 consists of only the core wire, an insulating film is formed to coat the coil element 6 exposed from the substrate 3 and the resin layer 10.

[0018] 3, a resin layer 10 serving as a first insulating layer seals the RFIC chip 7, and is laminated on the first main surface 4 of the substrate 3. The resin layer 10 is formed of a general sealing resin such as an epoxy resin.

[0019] Next, the substrate 3 will be described with reference to Figures 3 and 4. Figure 4 is a plan view showing wiring electrodes on the substrate 3. Figure 4(a) is a plan view showing wiring electrodes on the first main surface 4 of the substrate 3. Figure 4(b) is a perspective plan view seen through the substrate 3, showing wiring electrodes on the second main surface 5. The dashed dotted lines in Figure 4 indicate through-hole connections.

[0020] 3 and 4(a), a first land 19 connected to a first terminal 8 of the RFIC chip 7 via solder 23, and a second land 21 connected to a second terminal 9 of the RFIC chip 7 via solder 23 are arranged on the first main surface 4 of the substrate 3. Also arranged on the first main surface 4 of the substrate 3 are an electrode 27 that faces the first land 19 in the longitudinal direction of the substrate 3, and a conductor pattern 25 that connects the first land 19 to the electrode 27. The conductor pattern 25 has, for example, a linear shape that extends in the longitudinal direction of the substrate 3.

[0021] A second interlayer connection conductor 57 and a first interlayer connection conductor 55 are formed to penetrate the inside of the substrate 3. The first interlayer connection conductor 55 is a conductive via that connects the electrode 27 and the first electrode 29. The second interlayer connection conductor 57 is a conductive via that connects the second land 21 and the second electrode 31.

[0022] The first and second interlayer connection conductors 55, 57 are, for example, conductors formed by solidifying (metallizing) a conductive paste filled in a hole provided in the insulating substrate 3, but may also be plated through holes. The first and second interlayer connection conductors 55, 57 are disposed opposite each other in the longitudinal direction of the third substrate.

[0023] A first electrode 29 and a second electrode 31 connected to a first end 44 and a second end 45 of the coil element 6, respectively, are arranged on the second main surface 5 of the substrate 3. The first electrode 29 and the second electrode 31 face each other in the longitudinal direction of the substrate 3.

[0024] The first terminal 8 of the RFIC chip 7 is connected to the first end 44 of the coil element 6 via the solder 23 , the first land 19 , the conductor pattern 25 , the electrode 27 , the first interlayer connection conductor 55 , and the first electrode 29 .

[0025] The second terminal 9 of the RFIC chip 7 is connected to the second end 45 of the coil element 6 via the solder 23 , the second land 21 , the second interlayer connection conductor 57 , and the second electrode 31 .

[0026] 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 element 6 receives radio waves of the communication frequency, a current flows through the RFIC chip 7 .

[0027] In the conductor 41 of the coil element 6, the portion that contacts the second main surface 5 of the substrate 3 and the first electrode 29 and second electrode 31 on the second main surface are covered and protected by the resist layer 17. This makes it possible to prevent a short circuit between the metal outside the RFID module 1 and the coil element 6, the first electrode 29, and the second electrode 31, and to prevent an effect on the resonant frequency of the RFIC chip 7.

[0028] In one turn of the conductor 41 of the coil element 6, the conductor 41 protrudes from inside one side of the resist layer 17 of the RFID module 1 to the outside, then winds around one side of the substrate 3 and the resin layer 10, the upper surface of the resin layer 10, and the surface opposite the one side of the substrate 3 and the resin layer 10, and then again enters the inside from the surface opposite the one side of the resist layer 17. In this way, the coil element 6 winds around the outer periphery of the resin layer 10.

[0029] Since the longitudinal cross section of the RFID module 1 perpendicular to the winding axis Wa of the coil element 6 is rectangular, the opening P of the coil element 6 formed by the conductor 41 wound around a portion of the outer periphery of the RFID module 1 is also rectangular when viewed from the winding axis Wa, as shown in Fig. 5(a). Therefore, compared to the circular coil-shaped coil element 91 shown in Fig. 5(b), assuming that the diameter R of the circle and the side length L of the rectangle are the same, the rectangular opening has a larger opening area, and therefore the RFID module 1 of embodiment 1 has better antenna characteristics.

[0030] The manufacturing procedure for the RFID module 1 will be described. First, the conductors, namely, the first lands 19, the second lands 21, the conductor pattern 25, the electrodes 27, the first electrodes 29, and the second electrodes 31, are patterned on a large double-sided board by photolithography, for example, using copper foil. At this time, the wiring for multiple RFID modules 1 is patterned.

[0031] Next, an RFIC chip 7 is mounted on each of the first lands 19 and the second lands 21, and the RFIC chip 7 on the substrate is molded with a resin layer 10. Next, the molded large-sized double-sided substrate is diced into individual modules. At this time, barrel processing may be performed to round off the corners of the individual modules. Next, as shown in FIG. 6 , the second main surface 5 side of the substrate 3 of each individual module 2 is immersed in, for example, a UV-curable resin liquid 101 to adhere the UV-curable resin liquid 101 to the second main surface 5 side, and then UV irradiation is performed to form a resist layer 17, thereby manufacturing the RFID module 1.

[0032] As described above, the RFID module 1 of the first embodiment includes the substrate 3, the first electrode 29 and the second electrode 31 arranged on the substrate 3, the coil element 6 connected at one end to the first electrode 29 and the other end to the second electrode 31, the RFIC chip 7 electrically connected at one end to the first electrode 29 and the other end to the second electrode 31, and the resin layer 10 covering the RFIC chip 7. The coil element 6 is wound around the substrate 3, and at least a portion of the coil element 6 is exposed to the outside of the resin layer 10.

[0033] According to the RFID module 1 having this configuration, at least a portion of the coil element 6 is exposed to the outside of the resin layer 10, and therefore a portion of the coil element 6 reaches the outer periphery of the RFID module 1, making it possible to widen the opening of the coil element 6. This allows a magnetic field to be radiated widely from the coil element 6, improving the communication characteristics of the coil element 6 as an antenna.

[0034] By disposing the RFID module 1 inside a metal coil spring, for example, it is possible to excite the coil spring and increase the communication distance.

[0035] The substrate 3 has a first main surface 4 and a second main surface 5 facing each other, with the RFIC chip 7 arranged on the first main surface 4 and the first electrode 29 and the second electrode 31 arranged on the second main surface 5. The RFID module 1 has a resin layer 10 arranged on the first main surface 4 to cover the RFIC chip 7, and a resist layer 17 on the second main surface 5 to cover the first electrode 29 and the second electrode 31. The coil element 6 is wound around the substrate 3 and the resin layer 10.

[0036] This allows the coil element 6 to be exposed to the outside of the upper and side surfaces of the resin layer 10, so that the opening of the coil element 6 can be made larger, and communication characteristics can be further improved.

[0037] (Embodiment 2) Next, an RFID module 1A of embodiment 2 will be described with reference to Fig. 7 and Fig. 8. Fig. 7 is a plan view showing an outline of the RFID module 1A of embodiment 2. Fig. 8 is a cross-sectional view taken along line AA in Fig. 7.

[0038] The substrate 3A in the second embodiment is a single-sided substrate. Except for this and other points described below, the configuration of the RFID module 1A in the second 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.

[0039] The thickness of the substrate 3A of the second embodiment is greater than the thickness of the substrate 3 of the first embodiment, and is, for example, about 1 mm.

[0040] In the second embodiment, the first land 19A extends from the center of the substrate 3A to one end in the longitudinal direction, and the second land 21A extends from the center of the substrate 3A to the other end in the longitudinal direction. A first end 44A of the coil element 6A is connected to one end of the first land 19A, and a second end 45A of the coil element 6A is connected to the other end of the second land 21A. The first land 19A on the center side of the substrate 3A is connected to a first terminal 8 of the RFIC chip 7 via solder 23. The second land 21A on the center side of the substrate 3A is connected to a second terminal 9 of the RFIC chip 7 via solder 23.

[0041] An insulating resist layer 18 is laminated on the first land 19A on the side opposite to the substrate 3A, except for the connection portion with the first end 44A of the coil element 6A and the connection portion with the solder 23. An insulating resist layer 18 is also laminated on the second land 21A on the side opposite to the substrate 3A, except for the connection portion with the second end 45A of the coil element 6A and the connection portion with the solder 23. This prevents electrical continuity between the coil element 6A and the first land 19A and the second land 21A, even if the conducting wire 41 of the coil element 6A is wound from one end side of the first land 19A around the substrate 3A, the first land 19A, and the second land 21A.

[0042] The conductor 41 of the coil element 6A of the second embodiment has a conductive core wire and an insulating film covering the outer periphery of the core wire. In this case, it is also possible to perform communication by placing the second main surface 5A of the RFID module 1A on a metal surface so that it faces the metal surface. In this case, the RFID module 1A can communicate by exciting the metal surface. If the conductor 41 is composed of only a core wire, a resin layer may be formed to cover the coil element 6A on the second main surface 5A side of the substrate 3A.

[0043] An insulating resin layer 10A is laminated on the first main surface 4A of the substrate 3A, covering the RFID module 1A, the first lands 19A, the second lands 21A, and the coil element 6A. The resin layer 10A does not need to be formed by resin molding, and may be formed from, for example, a UV-curable resin. In this case, the resin layer is not formed by resin molding, so the RFID module 1 can be manufactured inexpensively.

[0044] 7, the RFIC chip 7 is disposed in the center of the coil element 6A in the longitudinal direction in a plan view. Since the coil element 6A is disposed symmetrically with the RFIC chip 7 at the center, symmetric communication characteristics can be obtained.

[0045] Furthermore, on the first main surface 4A side of the substrate 3A, the coil element 6A and the RFIC chip 7 do not overlap in plan view. This reduces the effect of the magnetic field induced by the current flowing through the coil element 6A on the RFIC chip 7. It also reduces the load on the RFIC chip caused by the winding tension of the coil element.

[0046] According to the RFID module 1A of the second embodiment, the substrate 3A has a first main surface 4A and a second main surface 5A facing each other, and the RFIC chip 7, a first land 19A as a first electrode, and a second land 21A as a second electrode are arranged on the first main surface 4A side. The coil element 6A is wound around the substrate 3A, and at least a portion of the coil element 6A is exposed to the outside of the resin layer 10A.

[0047] As a result, like the RFID module 1 of embodiment 1, the RFID module 1A of embodiment 2 also has at least a portion of the coil element 6A exposed to the outside of the resin layer 10A, thereby improving the communication characteristics of the coil element 6 as an antenna.

[0048] (Embodiment 3) Next, an RFID module 1B according to a third embodiment will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a plan view showing an outline of the RFID module 1B according to the third embodiment, from which the coil element is omitted. Fig. 10 is a plan view showing electrodes arranged on the substrate 3.

[0049] In the third embodiment, the connection point between the interlayer connection conductor and the electrode disposed on the second main surface 5 of the substrate 3 is offset from the connection point between this electrode and the coil element 6. Other than this point and points described below, the configuration of the RFID module 1B of the third embodiment is the same as that of the RFID module 1 of the first embodiment, and therefore a description of the common configuration will be omitted.

[0050] As shown in Figures 9 and 10(a), a first land 19B connected to the first terminal 8 of the RFIC chip 7 via solder 23 and a second land 21B connected to the second terminal 9 of the RFIC chip 7 via solder 23 are arranged on the first main surface 4, which is the upper surface of the substrate 3.

[0051] The first land 19B has an electrode 19Ba connected to the first terminal 8 of the RFIC chip 7, and an electrode 19Bb extending outward from the electrode 19Ba in the longitudinal direction of the substrate 3. The tip of the electrode 19Bb is connected to the upper end of the first interlayer connection conductor 55B that penetrates the substrate 3, and the lower end of the first interlayer connection conductor 55B is connected to the first electrode 29B arranged on the second main surface 5, which is the lower surface of the substrate 3.

[0052] The second land 21B has an electrode 21Ba connected to the second terminal 9 of the RFIC chip 7, and an electrode 21Bb extending outward from the electrode 21Ba in the longitudinal direction of the substrate 3. The tip of the electrode 21Bb is connected to the upper end of a second interlayer connection conductor 57B that penetrates the substrate 3, and the lower end of the second interlayer connection conductor 57B is connected to a second electrode 31B arranged on the second main surface 5, which is the lower surface of the substrate 3.

[0053] The first electrode 29B disposed on the second main surface 5 of the substrate 3 has an electrode 29Ba connected to the first interlayer connection conductor 55B, a wiring 29Bb extending from the electrode 29Ba outward in the longitudinal direction of the substrate 3, and an electrode 29Bc connected to the outer end of the wiring 29Bb. The electrode 29Bc is connected to the first end 44 of the coil element 6.

[0054] The second electrode 31B disposed on the second main surface 5 of the substrate 3 has an electrode 31Ba connected to the second interlayer connection conductor 57B, a wiring 31Bb extending from the electrode 31Ba outward in the longitudinal direction of the substrate 3, and an electrode 31Bc connected to the outer end of the wiring 31Bb. The electrode 31Bc is connected to the second end 45 of the coil element 6.

[0055] Electrode 29Ba and wiring 29Bb of first electrode 29B are covered and protected by resist layer 61. Electrode 31Ba and wiring 31Bb of second electrode 31B are covered and protected by resist layer 61. Connection portions between coil element 6 and electrodes 29Bc and 31Bc arranged on second main surface 5 of substrate 3 are exposed and are not covered by resist layer 61.

[0056] The first terminal 8 of the RFIC chip 7 is connected to the first end 44 of the coil element 6 via the solder 23, the first land 19B, the first inter-layer connection conductor 55B, and the first electrode 29B. The second terminal 9 of the RFIC chip 7 is connected to the second end 45 of the coil element 6 via the solder 23, the second land 21B, the second inter-layer connection conductor 57B, and the second electrode 31B.

[0057] In an electrode on the second main surface 5 of the substrate 3 that is connected to an interlayer connection conductor and a coil element, if the electrode and the coil element are connected along the extension of the interlayer connection conductor, the step in the interlayer connection conductor may affect the connection with the coil element.

[0058] The RFID module 1B of the third embodiment includes a first inter-layer connection conductor 55B that connects the RFIC chip 7 and the first electrode 29B by penetrating the substrate 3, and a second inter-layer connection conductor 57B that connects the RFIC chip 7 and the second electrode 31B by penetrating the substrate 3. An electrode 29Bc that is a connection point between the first electrode 29B and the coil element 6 is located further outward in the longitudinal direction of the substrate 3 than an electrode 29Ba that is a connection point between the first electrode 29B and the first inter-layer connection conductor 55B. An electrode 31Bc that is a connection point between the second electrode 31B and the coil element 6 is located further outward in the longitudinal direction of the substrate 3 than an electrode 31Ba that is a connection point between the second electrode 31B and the second inter-layer connection conductor 57B. In this way, electrode 29Ba connected to first inter-layer connection conductor 55B and electrode 29Bc connected to first end 44 of coil element 6 are positioned apart from each other, which prevents a step at the connection portion between first inter-layer connection conductor 55B and electrode 29Ba from affecting the connection between electrode 29Bc and first end 44 of coil element 6. Similarly, a step at the connection portion between second inter-layer connection conductor 57B and electrode 31Ba can be prevented from affecting the connection between electrode 31Bc and second end 45 of coil element 6.

[0059] In the RFID module 1B of the third embodiment, a matching capacitor 11 is connected in parallel to the RFIC chip 7 to the electrode 19Ba of the first land 19B and the electrode 21Ba of the second land 21B. The capacitance component of the capacitor 11 can reduce the resonance frequency of the RFID module 1B. The RFID module 1B may not necessarily be provided with the capacitor 11.

[0060] (Embodiment 4) Next, an RFID module 1C according to a fourth embodiment will be described with reference to Figs. 11 to 13. Fig. 11 is a side view showing an outline of the RFID module 1C according to a third embodiment. Fig. 12 is a vertical cross-sectional view of the RFID module 1C. Fig. 13 is an equivalent circuit diagram of the RFID module 1C.

[0061] The coil element 6C in the fourth embodiment extends in the longitudinal direction of the substrate 3 while winding outward from the substrate 3 and the resin layer 10. Except for this point and points described below, the configuration of the RFID module 1C in the fourth embodiment is the same as that of the RFID module 1 in the first embodiment or the RFID module 1B in the third embodiment, and therefore a description of the common configuration will be omitted.

[0062] As shown in Figure 12, on the first main surface 4, which is the upper surface of the substrate 3, there are arranged a first land 19C connected to the first terminal 8 of the RFIC chip 7 via solder 23, and a second land 21C connected to the second terminal 9 of the RFIC chip 7 via solder 23.

[0063] An outer end of the first land 19C in the longitudinal direction of the substrate 3 is connected to an upper end of a first interlayer connection conductor 55 that penetrates the substrate 3, and a lower end of the first interlayer connection conductor 55 is connected to a first electrode 29 disposed on the second main surface 5 of the substrate 3. The first electrode 29 is joined to the first connection portion 44C of the coil element 6C by, for example, solder 47. The first electrode 29 and the first connection portion 44C of the coil element 6C may be joined electrically by welding or ultrasonic waves, other than by solder 47.

[0064] An outer end of the second land 21C in the longitudinal direction of the substrate 3 is connected to an upper end of a second interlayer connection conductor 57 that penetrates the substrate 3, and a lower end of the second interlayer connection conductor 57 is connected to a second electrode 31 disposed on the second main surface 5 of the substrate 3. The second electrode 31 is joined to the second connection portion 45C of the coil element 6C by, for example, solder 47. The second electrode 31 and the second connection portion 45C of the coil element 6C may be joined electrically by welding or ultrasonic waves, other than by solder 47.

[0065] 13, the RFIC chip 7 has therein a feed point 7a and a capacitance C1. A first terminal 8 electrically connected to one of the feed point 7a and the capacitance C1 is connected to a first connection portion 44C of the coil element 6C via solder 23, a first land 19C, a first inter-layer connection conductor 55, and a first electrode 29. A second terminal 9 electrically connected to the other of the feed point 7a and the capacitance C1 is connected to a second connection portion 45C of the coil element 6C via solder 23, a second land 21C, a second inter-layer connection conductor 57, and a second electrode 31.

[0066] The joint portion between the first electrode 29 and the first connection portion 44C of the coil element 6C joined by the solder 47 is covered and protected by an insulating resist layer 17 such as resin. The joint portion between the second electrode 31 and the second connection portion 45C of the coil element 6C joined by the solder 47 is also covered and protected by the resist layer 17.

[0067] The coil element 6C has a first coil extension 6Ca and a second coil extension 6Cb that protrude further than the substrate 3 and the resin layer 10 in the longitudinal direction of the substrate 3. This allows the coil element 6C to function as a dipole antenna, thereby further improving communication performance.

[0068] Thus, according to the RFID module 1C of the fourth embodiment, the coil element 6C has, on one side, a first coil extension 6Ca that extends from the connection with the first electrode 29 further outward from the substrate 3, and, on the other side, a second coil extension 6Cb that extends from the connection with the second electrode 31 further outward from the substrate 3 in the direction opposite to the direction in which the first coil extension 6Ca extends. This can further improve the communication performance of the RFID module 1C.

[0069] The present invention is not limited to the above-described embodiments, but can be modified as follows.

[0070] In the first embodiment, the RFIC chip 7 is disposed at the end of the substrate 3, but this is not limiting. As in the second embodiment, the RFIC chip 7 may be disposed at the center of the substrate 3 together with the first lands 19 and the second lands 21. This places the RFIC chip 7 at the center of the coil element 6 in the longitudinal direction in a plan view. When the coil element 6 is disposed symmetrically around the RFIC chip 7, symmetrical communication characteristics can be obtained. Furthermore, the load transmitted to the RFIC chip 7 when connecting the coil element 6 to the first electrode 29 and the second electrode 31 can be reduced.

[0071] 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.

[0072] An RFID module according to a first aspect of the present invention includes a substrate, first and second electrodes disposed on the substrate, a coil element connected at one end to the first electrode and at the other end to the second electrode, an RFIC chip electrically connected at one end to the first electrode and at the other end to the second electrode, and a first insulating layer covering the RFIC chip. The coil element wraps around the substrate, and at least a portion of the coil element is exposed to the outside of the first insulating layer.

[0073] According to this RFID module, at least a portion of the coil element is exposed to the outside of the first insulating layer, and therefore a portion of the coil element reaches the outer periphery of the RFID module, allowing the opening of the coil element to be widened, thereby enabling the magnetic field to be radiated widely from the coil element and improving the communication characteristics of the coil element as an antenna.

[0074] According to a second aspect, in the RFID module of the first aspect, the coil element has a conductor wound multiple times, and the winding pitch of the conductor is larger than the wire diameter of the conductor. As a result, the coil element has gaps between adjacent wound conductors, which makes it easier for the magnetic field generated by the coil element to be released to the outside and for magnetic field coupling to occur, thereby improving communication characteristics.

[0075] According to a third aspect, in the RFID module of the first or second aspect, the substrate has a first main surface and a second main surface facing each other, an RFIC chip is arranged on the first main surface, first electrodes and second electrodes are arranged on the second main surface, a first insulating layer covering the RFIC chip is arranged on the first main surface, a second insulating layer covering at least a portion of the first electrodes and the second electrodes is provided on the second main surface, and the coil element is wound around the substrate and the first insulating layer. This makes it possible to use a double-sided substrate as the substrate, and even with this configuration, it is possible to realize an RFID module with improved communication characteristics.

[0076] According to a fourth aspect, in the RFID module of any one of the first to third aspects, the cross section of the first insulating layer perpendicular to the winding axis of the coil element is rectangular. Since the opening of the coil element can be made rectangular, communication characteristics can be improved compared to a coil element with a circular opening.

[0077] According to the fifth aspect, the substrate of the first or second aspect has a first main surface and a second main surface facing each other, and the RFIC chip, the first electrode, and the second electrode are arranged on the first main surface side. This makes it possible to use a single-sided substrate as the substrate, and even with this configuration, it is possible to realize an RFID module with improved communication characteristics.

[0078] According to a sixth aspect, in the RFID module of any one of the first to third aspects, the RFIC chip is disposed at the center of the coil element in the longitudinal direction in a plan view, whereby the coil elements are disposed symmetrically with respect to the RFIC chip, thereby achieving symmetric communication characteristics.

[0079] According to the seventh aspect, in the RFID module of the sixth aspect, the coil element and the RFIC chip do not overlap in plan view on the first main surface side of the substrate, thereby reducing the influence of the magnetic field induced by the current flowing through the coil element on the RFIC chip.

[0080] According to an eighth aspect, the RFID module of the third aspect further includes a first inter-layer connection conductor that connects the RFIC chip and the first electrode by penetrating the substrate, and a second inter-layer connection conductor that connects the RFIC chip and the second electrode by penetrating the substrate. The connection point between the first electrode and the coil element is located further outward in the longitudinal direction of the substrate than the connection point between the first electrode and the first inter-layer connection conductor, and the connection point between the second electrode and the coil element is located further outward in the longitudinal direction of the substrate than the connection point between the second electrode and the second inter-layer connection conductor. This reduces the influence of steps at the connection points between the inter-layer connection conductors and the electrodes on the connection points between the coil element and each electrode.

[0081] According to a ninth aspect, in the RFID module of the third or eighth aspect, the coil element has a first coil extension on one side that extends from the connection with the first electrode further outward from the substrate 3, and a second coil extension on the other side that extends from the connection with the second electrode further outward from the substrate 3 in the opposite direction to the extension of the first coil extension, thereby improving communication characteristics. [Explanation of symbols]

[0082] 1. 1A RFID module 2 Modules 3, 3A board 4, 4A First main surface 5, 5A 2nd main surface 6, 6A, 6C coil elements 7 RFIC chips 7a Power supply point 8 1st terminal 9 2nd terminal 10, 10A resin layer 11 Capacitor 17 Resist layer 18 Resist layer 19, 19A, 19B, 19C 1st Land 21, 21A, 21B, 21C Land 2 23 Solder 25 Conductor Pattern 27 electrodes 29, 29B 1st electrode 29Ba electrode 29Bb wiring 29Bc electrode 31, 31B 2nd electrode 31Ba electrode 31Bb wiring 31Bc electrode 41 Conductor 44, 44A 1st end 44C First connection part 45, 45A 2nd end 45C Second connection part 47 Solder 55, 55B First interlayer connecting conductor 57 Second interlayer connecting conductor 61 Resist layer 91 Coil element 101 UV curing resin liquid Wa Winding shaft

Claims

1. A substrate; a first electrode and a second electrode disposed on the substrate; a coil element connected at one end to the first electrode and at the other end to the second electrode; an RFIC chip electrically connected to the first electrode and the second electrode; a first insulating layer covering the RFIC chip; the coil element is wound around the substrate, and at least a portion of the coil element is exposed to the outside of the first insulating layer; The coil element a first coil extension portion extending from a connection portion with the first electrode on one side to an outside of the substrate; and a second coil extension portion on the other side extending from the connection portion with the second electrode further outward from the substrate in a direction opposite to the direction in which the first coil extension portion extends. RFID module.

2. The coil element has a conductive wire wound multiple times, The winding pitch of the conductor is larger than the wire diameter of the conductor. The RFID module according to claim 1 .

3. the substrate has a first main surface and a second main surface facing each other, The RFIC chip is disposed on the first main surface side, the first electrode and the second electrode are disposed on the second principal surface side, the first insulating layer is disposed on the first main surface; a second insulating layer on the second main surface that covers at least a portion of the first electrode and the second electrode; the coil element is wound around the substrate and the first insulating layer; The RFID module according to claim 1 .

4. a cross section of the first insulating layer perpendicular to the winding axis of the coil element is rectangular; The RFID module according to claim 1 .

5. the substrate has a first main surface and a second main surface facing each other, the RFIC chip, the first electrode, and the second electrode are arranged on the first main surface side; The RFID module according to claim 1 .

6. The RFIC chip is disposed at the center of the coil element in a longitudinal direction in a plan view. The RFID module according to claim 1 .

7. On the first main surface side of the substrate, the coil element and the RFIC chip do not overlap in a plan view. The RFID module according to claim 6 .

8. a first interlayer connection conductor that connects the RFIC chip and the first electrode through the substrate; a second interlayer connection conductor that connects the RFIC chip and the second electrode through the substrate, a connection point between the first electrode and the coil element is located outside a connection point between the first electrode and the first interlayer connection conductor in a substrate longitudinal direction; a connection point between the second electrode and the coil element is located outside a connection point between the second electrode and the second interlayer connection conductor in a substrate longitudinal direction; The RFID module according to claim 3 .

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