Antenna equipment

Abstract

To provide an antenna device further improved in antenna characteristics.SOLUTION: An antenna device 10 comprises a substrate 500 and a coil antenna 100. The substrate 500 has a planar conductive part 510. An opening 512 and a slit are formed in the conductive part 510. The coil antenna 100 is mounted on the substrate 500 so as to at least partially overlap the opening 512 when seen from a vertical direction orthogonal to the substrate 500. The coil antenna 100 is provided with a coil 200 and a magnetic core 300. The coil 200 has a winding axis AX extending vertically. The magnetic core 300 partially forms a magnetic path of the coil 200. The magnetic core 300 is positioned in a region excluding a specific region SR directly below the coil 200. The magnetic core 300 has at least a center core 310. The center core 310 is at least partially positioned on the inner side of the coil 200.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an antenna device including a substrate and a coil antenna.

Background Art

[0002] As shown in FIG. 31, Patent Document 1 discloses an antenna device 900 of this type. The antenna device 900 can be used for communication such as NFC (Near Field Communication) and RFID (Radio Frequency Identifier). The antenna device 900 includes a substrate 910, a first coil antenna (coil antenna) 930, and a second coil antenna (coil antenna) 940. As shown in FIG. 32, a planar conductor (conductor portion) 922 is formed on the first main surface 920 of the substrate 910. The conductor portion 922 is formed with a first opening (opening portion) 9222, a second opening (opening portion) 9224, a first slit (slit) 9223, and a second slit (slit) 9225. The slit 9223 is connected to the opening 9222. The slit 9225 is connected to the opening 9224. Referring to FIGS. 31 and 32, when viewed along the direction (Z direction) orthogonal to the substrate 910, the coil antenna 930 is mounted on the substrate 910 so as to partially overlap the opening 9222. The coil antenna 940 is mounted on the substrate 910 so as to partially overlap the opening 9224 when viewed along the direction (Z direction) orthogonal to the substrate 910. Each of the coil antennas 930 and 940 includes a coil (not shown) having a winding axis in the direction (Z direction) orthogonal to the first main surface 920, and a laminate (not shown) of an insulating base material layer such as a magnetic body ferrite.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] In antenna devices such as the antenna device 900 described in Patent Document 1, there is a need for further improvement in antenna characteristics.

[0005] Therefore, the present invention aims to provide an antenna device in which antenna characteristics are further improved. [Means for solving the problem]

[0006] In a coil antenna in which the coil is completely embedded in a magnetic core, a closed magnetic path is formed in the magnetic core. The inventors of the present invention noticed that when an antenna device such as antenna device 900 is constructed with such a coil antenna, the magnetic flux generated from the coil passes through the closed magnetic path formed by the magnetic core, thus weakening the coupling between the current loop flowing around the outer circumference of the slit in the substrate and the coil antenna. Therefore, the inventors of the present invention devised a way to construct the antenna device such that the magnetic core is not located directly beneath the coil of the coil antenna, so that the magnetic flux generated from the coil forms an open magnetic path. The inventors of the present invention found that this new configuration can strengthen the coupling between the current loop flowing around the outer circumference of the slit in the substrate and the coil antenna, and thus completed the present invention.

[0007] In other words, the present invention provides a first antenna device, An antenna device comprising a substrate and a coil antenna, The substrate has a planar conductive portion, The aforementioned conductor portion has an opening and a slit formed therein. The path encircling the opening and the slit in the conductor portion constitutes part of the resonant circuit. The slit is connected to the opening, The coil antenna is mounted on the substrate such that it at least partially overlaps the opening when viewed along the vertical direction perpendicular to the substrate. The coil antenna comprises a coil and a magnetic core. The coil has a winding shaft that extends in the vertical direction, The magnetic core partially constitutes the magnetic path of the coil, The magnetic core is located in a region excluding a specific region directly below the coil. The magnetic core has at least a central core, The core is located at least partially inside the coil. We provide antenna equipment.

[0008] Furthermore, the present invention provides a second antenna device, which is a first antenna device, The substrate has an edge, The slit extends toward the edge. We provide antenna equipment.

[0009] Furthermore, the present invention provides a third antenna device, which is a first antenna device, The aforementioned conductor portion is further formed with additional openings. The path encircling the additional opening in the conductor portion constitutes a part of the resonant circuit. The slit is connected to both the opening and the additional opening, The coil antenna is mounted on the substrate in such a way that it does not overlap with the additional opening when viewed along the vertical direction. We provide antenna equipment.

[0010] Furthermore, the present invention also includes a fourth antenna device, which is a third antenna device, The substrate has an edge, The aforementioned conductor portion is further formed with additional slits. The additional slit extends toward the edge, The antenna device further includes a capacitor that constitutes part of the resonant circuit. The capacitor is mounted on the substrate so as to straddle the additional slit. Provide an antenna device.

[0011] Moreover, the present invention provides, as a fifth antenna device, a fourth antenna device, wherein All of the opening, the slit, the additional opening, and the additional slit are connected to each other. Provide an antenna device.

[0012] Moreover, the present invention provides, as a sixth antenna device, a first antenna device, wherein The core extends downward below the lower end of the coil in the vertical direction. Provide an antenna device.

[0013] Moreover, the present invention provides, as a seventh antenna device, a first antenna device, wherein The core extends upward above the upper end of the coil in the vertical direction. Provide an antenna device.

[0014] Moreover, the present invention provides, as an eighth antenna device, a seventh antenna device, wherein The magnetic core further has an upper portion, The upper portion extends from the core toward the outer periphery of the coil, The upper portion overlaps the coil when viewed from the vertical direction. Provide an antenna device.

[0015] Moreover, the present invention provides, as a ninth antenna device, an eighth antenna device, wherein The magnetic core further has a side portion, The side portion is located outside the coil in a plane orthogonal to the vertical direction, The side portion extends downward in the vertical direction from the upper portion. Provide an antenna device.

[0016] Furthermore, the present invention also includes a tenth antenna device, which is a first antenna device, The substrate has an edge, The slit has a predetermined portion, The predetermined portion extends along the edge in the vicinity of the edge. We provide antenna equipment.

[0017] Furthermore, the present invention also includes a 10th antenna device as an 11th antenna device, The antenna device further includes a capacitor that constitutes part of the resonant circuit. The capacitor is mounted in the region between the edge and the slit on the substrate. We provide antenna equipment.

[0018] Furthermore, the present invention also includes a twelfth antenna device, which is a tenth antenna device, The slit has a first portion and a second portion, The first portion extends from the opening toward the edge, The second portion extends from the first portion in a direction intersecting the first portion, The second part is the predetermined part. We provide antenna equipment.

[0019] Furthermore, the present invention also includes a 12th antenna device as a 13th antenna device, The aforementioned slit further comprises a third portion, The third portion extends from the second portion in a direction intersecting with the second portion. We provide antenna equipment.

[0020] Furthermore, the present invention also includes a 14th antenna device, which is a first antenna device, When the cross-sectional area of ​​the inner circumference of the coil is S1 and the area of ​​the opening is S2, the condition 1 ≤ S2 / S1 ≤ 2 is satisfied. We provide antenna equipment. [Effects of the Invention]

[0021] The antenna device of the present invention is configured as follows: The coil antenna is mounted on the substrate so as to at least partially overlap the opening when viewed along the vertical direction perpendicular to the substrate; the magnetic core is located in the region excluding a specific area directly below the coil; the magnetic core has at least a central core; the central core is located at least partially inside the coil. As a result, in the antenna device of the present invention, the coupling between the current loop flowing around the outer circumference of the slit in the substrate and the coil antenna is strengthened. That is, the antenna device of the present invention achieves further improvement in antenna characteristics. [Brief explanation of the drawing]

[0022] [Figure 1] This is a perspective view showing an antenna device according to a first embodiment of the present invention. [Figure 2] Figure 1 is a top view showing the antenna device. [Figure 3] This is a cross-sectional view of a portion of the antenna device shown in Figure 2, along line AA. The resin mold, terminals, and pads are omitted in the figure. [Figure 4] Figure 1 is a perspective view showing the coil antenna included in the antenna device. [Figure 5] Figure 4 is a side view showing the coil antenna. [Figure 6] Figure 4 is a top view showing a coil antenna. [Figure 7] Figure 4 is a front view showing the coil antenna. [Figure 8] Figure 4 is a perspective view showing the coil antenna with the resin mold removed. [Figure 9] Figure 8 is a side view showing the coil antenna. [Figure 10] Figure 8 is a top view showing a coil antenna. [Figure 11] Figure 8 is a front view showing the coil antenna. [Figure 12]Figure 2 is a top view showing the circuit board included in the antenna device. [Figure 13] Figure 4 is a perspective view showing a first modified example of the coil antenna. [Figure 14] Figure 13 is a side view showing the coil antenna. [Figure 15] Figure 13 is a top view showing a coil antenna. [Figure 16] Figure 13 is a front view showing the coil antenna. [Figure 17] Figure 13 is a perspective view showing the coil antenna with the resin mold removed. [Figure 18] Figure 17 is a side view showing a coil antenna. [Figure 19] Figure 17 is a top view showing a coil antenna. [Figure 20] Figure 19 is a cross-sectional view of the coil antenna along the BB line. [Figure 21] Figure 17 is a front view showing a coil antenna. [Figure 22] Figure 4 is a perspective view showing a second modified example of the coil antenna. [Figure 23] Figure 22 is a side view showing the coil antenna. [Figure 24] Figure 22 is a top view showing a coil antenna. [Figure 25] Figure 24 is a cross-sectional view of the coil antenna along the CC line. The resin mold is omitted in the figure. [Figure 26] Figure 22 is a front view showing the coil antenna. [Figure 27] This is a top view showing an antenna device according to a second embodiment of the present invention. [Figure 28] This is a top view showing an antenna device according to a third embodiment of the present invention. [Figure 29] This is a top view showing an antenna device according to a fourth embodiment of the present invention. [Figure 30] This is a top view showing an antenna device according to a fifth embodiment of the present invention. [Figure 31]This is a top view showing the antenna device described in Patent Document 1. [Figure 32] Figure 31 is a top view showing the circuit board included in the antenna device. [Modes for carrying out the invention]

[0023] (First embodiment) As shown in Figure 1, the antenna device 10 according to the first embodiment of the present invention comprises a substrate 500 and a coil antenna 100.

[0024] As shown in Figure 12, the substrate 500 of this embodiment has a planar conductive portion 510. More specifically, the conductive portion 510 is a ground conductor. Specifically, the substrate 500 has a conductive layer as the conductive portion 510 laminated on an insulating substrate such as a glass epoxy substrate.

[0025] As shown in Figure 12, the conductor portion 510 has an opening 512 and a slit 514. The path that circulates around the opening 512 and the slit 514 in the conductor portion 510 constitutes part of the resonant circuit.

[0026] Referring to Figure 12, the opening 512 in this embodiment is a portion of the substrate 500 that does not have a conductive pattern. The opening 512 has a substantially circular outer edge when the substrate 500 is viewed from above in the vertical direction. However, the present invention is not limited to this, and the opening 512 may have an outer edge of a shape other than substantially circular. In this embodiment, the vertical direction is the Z direction. Also, upward is the +Z direction, and downward is the -Z direction.

[0027] As shown in Figure 12, the slit 514 in this embodiment, like the opening 512, is a portion on the substrate 500 that does not have a conductive pattern. The slit 514 is connected to the opening 512. The slit 514 extends from the opening 512. In this embodiment, there is one slit 514 extending from the opening 512. However, the present invention is not limited thereto, and multiple slits 514 may extend from the opening 512. The slit 514 does not communicate with the outside of the conductive portion 510 in a plane perpendicular to the vertical direction. The slit 514 has a predetermined portion PP. The slit 514 has a first portion 5142 and a second portion 5144.

[0028] As shown in Figure 12, the width of the slit 514 is smaller than the diameter of the opening 512. However, the present invention is not limited to this, and the width of the slit 514 and the diameter of the opening 512 may be the same, or the width of the slit 514 may be larger than the diameter of the opening 512. Increasing the width of the slit 514 increases the current loop formed around the slit 514, thereby increasing the communication distance of the antenna device 10.

[0029] As shown in Figure 12, the first portion 5142 extends to the right in the left-right direction from the opening 512. In this embodiment, the left-right direction is the Y direction. Here, the right is the +Y direction and the left is the -Y direction.

[0030] As shown in Figure 12, the second portion 5144 extends from the first portion 5142 in a direction intersecting the first portion 5142. The second portion 5144 extends from the right end of the first portion 5142 in the rearward direction. In this embodiment, the rearward direction is the X direction. Here, the front is the +X direction and the rear is the -X direction. The second portion 5144 is a predetermined portion PP.

[0031] As shown in Figure 12, the slit 514 further comprises a third portion 5146.

[0032] As shown in Figure 12, the third portion 5146 extends from the second portion 5144 in a direction that intersects with the second portion 5144. The third portion 5146 extends to the left in the left-right direction from the rear end of the second portion 5144.

[0033] As shown in Figure 12, the substrate 500 has an edge 520.

[0034] As shown in Figure 12, edge 520 defines the outer edge of the substrate 500. That is, edge 520 defines the outer edge of the substrate 500 in a direction perpendicular to the vertical direction. The slit 514 extends from the opening 512 toward edge 520, then bends and extends along edge 520, and then bends again and extends away from edge 520. The slit 514 does not reach edge 520. The first portion 5142 extends from the opening 512 toward edge 520. The predetermined portion PP extends along edge 520 in the vicinity of edge 520. This makes it possible to secure a large area on the substrate 500 where electronic components can be placed, and also increases the length of the slit 514, thereby increasing the current loop formed around the slit 514 and increasing the communication distance of the antenna device 10.

[0035] As described above, the slit 514 extends from the opening 512 toward the edge 520, then bends and extends along the edge 520, and then bends again and extends away from the edge 520. The slit 514 does not reach the edge 520, and the slit 514 does not communicate with the outside of the conductor portion 510 in a plane perpendicular to the vertical direction. However, the present invention is not limited thereto, and the slit 514 may extend toward the edge 520, or may reach the edge 520. That is, the slit 514 may communicate with the outside of the conductor portion 510 in a plane perpendicular to the vertical direction.

[0036] Referring to Figures 2 and 12, the coil antenna 100 is mounted on the substrate 500 such that it at least partially overlaps the opening 512 when viewed along the vertical direction perpendicular to the substrate 500. The coil antenna 100 is surface-mounted on the substrate 500. In other words, the coil antenna 100 is a surface-mount type antenna.

[0037] As shown in Figure 3, the coil antenna 100 comprises a coil 200 and a magnetic core 300.

[0038] As shown in Figure 3, the coil 200 of this embodiment has a winding shaft AX extending in the vertical direction. The coil 200 is formed by edgewise winding of a flat rectangular insulated wire. However, the present invention is not limited to this, and the coil 200 may also be made by winding an insulated round wire, and the material, cross-sectional shape, and winding method of the conductor are not limited to this embodiment. When viewed along the vertical direction, the coil 200 has a circular shape. However, the present invention is not limited to this, and the coil 200 may have a shape other than a circular shape.

[0039] Referring to Figures 3 and 12, when the cross-sectional area of ​​the inner circumference 240 of the coil 200 is S1 and the area of ​​the opening 512 is S2, the condition 1 ≤ S2 / S1 ≤ 2 is satisfied. This allows the coupling coefficient between the coil antenna 100 and the slit 514 to be maximized, making it easier for the coil antenna 100 to magnetically couple with the current (current loop) circulating around the opening 512 and the slit 514 in the conductor portion 510.

[0040] Referring to Figure 3, the magnetic core 300 in this embodiment is a cast core. More specifically, the magnetic core 300 is a composite magnetic material in which soft magnetic alloy powder, such as an iron-based alloy or ferrite, is dispersed inside a hardened binder. That is, the magnetic core 300 is made by hardening a slurry containing soft magnetic alloy powder and a binder. Note that the magnetic core 300 is not limited to this and can be manufactured by any manufacturing method. The magnetic core 300 partially constitutes the magnetic path of the coil 200. The magnetic core 300 is located in the region excluding the specific region SR directly below the coil 200. That is, the magnetic core 300 does not have a portion located directly below the coil 200. The specific region SR is the region hidden below the coil 200 when the coil 200 is viewed from above. The specific region SR is located below the lower end 220 of the coil 200 in the vertical direction. The specific region SR is located outside the inner circumference 240 of the coil 200 in the radial direction perpendicular to the winding axis AX. The specific region SR is located inside the outer circumference 230 of the coil 200 in the radial direction perpendicular to the winding axis AX. The magnetic core 300 has at least a central core 310.

[0041] Referring to Figure 3, the core 310 in this embodiment has a cylindrical shape extending in the vertical direction. The core 310 is located at least partially inside the coil 200. The central axis of the cylindrical shape of the core 310 coincides with the winding axis AX of the coil 200. The cross-sectional area of ​​the core 310 perpendicular to the vertical direction is smaller than the diameter of the opening 512. The projection image of the core 310 onto the substrate 500 in the vertical direction is located within the opening 512.

[0042] As described above, the coil antenna 100 is mounted on the substrate 500 such that it at least partially overlaps with the opening 512 when viewed along the vertical direction perpendicular to the substrate 500, the magnetic core 300 is located in the region excluding the specific region SR directly below the coil 200, the magnetic core 300 has at least a central core 310, and the central core 310 is at least partially located inside the coil 200. As a result, in the antenna device 10 of this embodiment, a portion of the magnetic flux of the coil 200 is directed toward the opening 512 of the substrate 500, making it easier for the coil antenna 100 to magnetically couple with the current (current loop) circulating around the opening 512 and slit 514 in the conductor portion 510. In other words, in the antenna device 10 of this embodiment, the coupling between the current loop flowing around the outer circumference of the slit 514 of the substrate 500 and the coil antenna 100 is strengthened, further improving the antenna characteristics.

[0043] As shown in Figure 3, the core 310 extends below the lower end 220 of the coil 200 in the vertical direction. As a result, in the antenna device 10 of this embodiment, a portion of the magnetic flux of the coil 200 is directed towards the opening 512 of the substrate 500, making it easier for the coil antenna 100 to magnetically couple with the current (current loop) circulating around the opening 512 and slit 514 in the conductor portion 510. In other words, in the antenna device 10 of this embodiment, the coupling between the current loop flowing around the outer circumference of the slit 514 (see Figure 12) of the substrate 500 and the coil antenna 100 is further strengthened, resulting in a further improvement in antenna characteristics.

[0044] As shown in Figure 3, the core 310 extends above the upper end 210 of the coil 200 in the vertical direction.

[0045] As shown in Figure 3, the magnetic core 300 further has an upper part 320.

[0046] As shown in Figure 3, the upper part 320 extends from the core 310 toward the outer circumference 230 of the coil 200. In the radial direction perpendicular to the central axis of the cylindrical shape of the core 310, the outer end of the upper part 320 is located outside the outer circumference 230 of the coil 200. The upper part 320 overlaps with the coil 200 when viewed from above. This allows the magnetic flux from the coil 200 that has flowed through the core 310 to the upper side of the magnetic core 300 to be efficiently directed toward the outer circumference 230 of the coil 200.

[0047] As shown in Figure 7, the coil antenna 100 further has two terminals 400.

[0048] Referring to Figure 8, in this embodiment, the terminals 400 are attached to the ends of the coil 200. However, the present invention is not limited thereto, and the terminals 400 may be formed by extending the ends of the coil 200. The terminals 400 define the lower end of the coil antenna 100. The terminals 400 are connected to a communication circuit (not shown) via pads (not shown) on the substrate 500.

[0049] As shown in Figure 4, the coil antenna 100 is equipped with a resin mold 700.

[0050] Referring to Figures 5 and 9, the resin mold 700 covers the coil 200. Referring to Figures 3, 5, and 7, the specific region SR is filled with the resin mold 700. That is, the resin mold 700 is located directly beneath the coil 200.

[0051] As shown in Figure 2, the antenna device 10 further includes a capacitor 600 that constitutes part of the resonant circuit.

[0052] Referring to Figure 12, the capacitor 600, together with the path circling around the opening 512 and slit 514 in the conductor portion 510, constitutes a current loop path. That is, the capacitor 600, together with the path circling around the opening 512 and slit 514 in the conductor portion 510, constitutes a resonant circuit. The resonant frequency of this resonant circuit is the communication frequency band of the antenna device 10. The capacitor 600 is mounted in the region between the edge 520 and the slit 514 on the substrate 500. More specifically, the capacitor 600 is mounted in the region between the edge 520 and the second portion 5144 on the substrate 500. Note that the placement of the capacitor 600 is not limited to the above location, and it may be placed anywhere on the conductor portion 510 as long as the capacitor 600 and the path circling around the opening 512 and slit 514 in the conductor portion 510 constitute a current loop path.

[0053] The configuration of the coil antenna 100 is not limited to those described above, and variations such as the following are possible.

[0054] (First variation) Referring to Figures 13 and 20, the coil antenna 100A according to the first modification of the present invention comprises a coil 200 and a magnetic core 300A. The coil 200 in this modification is the same as the coil 200 in the above-described embodiment, and a detailed description is omitted.

[0055] Referring to Figure 20, the magnetic core 300A in this embodiment is a cast core, similar to the magnetic core 300 described above. The magnetic core 300A partially constitutes the magnetic path of the coil 200. The magnetic core 300A is located in the region excluding a specific region SR directly below the coil 200. The specific region SR is the region hidden below the coil 200 when viewed from above. The specific region SR is located below the lower end 220 of the coil 200 in the vertical direction. The specific region SR is located outside the inner circumference 240 of the coil 200 in the radial direction perpendicular to the winding axis AX. The specific region SR is located inside the outer circumference 230 of the coil 200 in the radial direction perpendicular to the winding axis AX. The magnetic core 300A has a central core 310.

[0056] Referring to Figures 17 and 20, the core 310 in this embodiment has a cylindrical shape that extends in the vertical direction. The core 310 is partially located inside the coil 200.

[0057] As shown in Figure 20, the core 310 extends below the lower end 220 of the coil 200 in the vertical direction. The core 310 also extends above the upper end 210 of the coil 200 in the vertical direction.

[0058] Referring to Figures 10 and 20, the magnetic core 300A differs from the magnetic core 300 in that it does not have an upper portion 320.

[0059] As shown in Figure 13, the coil antenna 100A is equipped with a resin mold 700A.

[0060] Referring to Figures 14 and 18, the resin mold 700A covers the coil 200. Referring to Figure 20, the specific region SR is filled with the resin mold 700A. That is, the resin mold 700A is located directly below the coil 200. Note that, referring to Figure 15, the upper end of the core 310 is not covered by the resin mold 700A.

[0061] In this modified antenna device (not shown) in which the coil antenna 100A is mounted on the substrate 500, the same effects as in the above-described embodiment can be enjoyed.

[0062] (Second variation) Referring to Figures 22 and 25, the second modified coil antenna 100B of the present invention comprises a coil 200 and a magnetic core 300B. The coil 200 in this modified example is the same as the coil 200 in the above-described embodiment, and a detailed explanation is omitted.

[0063] Referring to Figure 25, the magnetic core 300B in this embodiment is a cast core, similar to the magnetic core 300 described above. The magnetic core 300B partially constitutes the magnetic path of the coil 200. The magnetic core 300B is located in the region excluding a specific region SR directly below the coil 200. The specific region SR is the region hidden below the coil 200 when viewed from above. The specific region SR is located below the lower end 220 of the coil 200 in the vertical direction. The specific region SR is located outside the inner circumference 240 of the coil 200 in the radial direction perpendicular to the winding axis AX. The specific region SR is located inside the outer circumference 230 of the coil 200 in the radial direction perpendicular to the winding axis AX. The magnetic core 300B has at least a core 310.

[0064] Referring to Figure 25, the core 310 in this embodiment has a cylindrical shape that extends in the vertical direction. The core 310 is located at least partially inside the coil 200.

[0065] As shown in Figure 25, the core 310 extends below the lower end 220 of the coil 200 in the vertical direction. The core 310 also extends above the upper end 210 of the coil 200 in the vertical direction.

[0066] As shown in Figure 25, the magnetic core 300B further has an upper section 320B. The upper section 320B in this modified example is the same as the upper section 320 in the embodiment described above, and a detailed explanation is omitted.

[0067] As shown in Figure 25, the magnetic core 300B further has a side portion 340.

[0068] As shown in Figure 25, the side portion 340 of this embodiment is located outside the coil 200 in a plane perpendicular to the vertical direction. The side portion 340 extends downward from the upper portion 320B in the vertical direction. This allows the magnetic flux of the coil 200 that has passed through the upper portion 320B to flow efficiently downward towards the coil 200. The side portion 340 covers the entire outer circumference 230 of the coil 200. However, the present invention is not limited to this, and the side portion 340 may be configured to cover only a part of the outer circumference 230 of the coil 200.

[0069] Referring to Figure 25, the coil antenna 100B is equipped with a resin mold (not shown).

[0070] Referring to Figure 25, the resin mold in this modified example covers the coil 200. The specific region SR is filled with the resin mold. That is, the resin mold is located directly beneath the coil 200.

[0071] In this modified antenna device (not shown) in which the coil antenna 100B is mounted on the substrate 500, the same effects as in the above-described embodiment can be enjoyed.

[0072] (Second embodiment) As shown in Figure 27, the antenna device 10C according to the second embodiment of the present invention comprises a substrate 500C and a coil antenna 100. The coil antenna 100 in this embodiment has the same structure as the coil antenna 100 in the first embodiment, and a detailed explanation is omitted. In addition, the same expressions as those in the first embodiment will be used below for direction and orientation in this embodiment.

[0073] As shown in Figure 27, the substrate 500C of this embodiment has a planar conductive portion 510C. More specifically, the conductive portion 510C is a ground conductor. Specifically, the substrate 500C has a conductive layer as the conductive portion 510C laminated on an insulating substrate such as a glass epoxy substrate.

[0074] As shown in Figure 27, the conductor portion 510C has an opening 512 and a slit 514C. The opening 512 in this embodiment has the same structure as the opening 512 in the first embodiment, and a detailed explanation is omitted. The path circulating around the opening 512 and the slit 514C in the conductor portion 510C constitutes part of the resonant circuit.

[0075] As shown in Figure 27, the slit 514C in this embodiment, like the opening 512, is a portion on the substrate 500C that does not have a conductive pattern. The slit 514C is connected to the opening 512. The slit 514C extends from the opening 512. The slit 514C does not communicate with the outside of the conductive portion 510C in a plane perpendicular to the vertical direction. The slit 514C has a predetermined portion PP. The slit 514C has a first portion 5142 and a second portion 5144.

[0076] As shown in Figure 27, the width of the slit 514C is smaller than the diameter of the opening 512. However, the present invention is not limited to this, and the width of the slit 514C and the diameter of the opening 512 may be the same, or the width of the slit 514C may be larger than the diameter of the opening 512. Increasing the width of the slit 514C increases the current loop formed around the slit 514C, thereby increasing the communication distance of the antenna device 10C.

[0077] As shown in Figure 27, the first portion 5142 extends to the right in the left-right direction from the opening 512.

[0078] As shown in Figure 27, the second portion 5144 extends from the first portion 5142 in a direction intersecting the first portion 5142. The second portion 5144 extends backward in the anterior-posterior direction from the right end of the first portion 5142. The second portion 5144 is a predetermined portion PP.

[0079] Referring to Figures 2 and 27, the slit 514C differs from the slit 514 in the first embodiment in that it does not have a third portion 5146.

[0080] As shown in Figure 27, the substrate 500C has an edge 520.

[0081] As shown in Figure 27, the edge 520 in this embodiment defines the outer edge of the substrate 500C. That is, the edge 520 defines the outer edge of the substrate 500C in a direction perpendicular to the vertical direction. The first portion 5142 extends from the opening 512 toward the edge 520. The predetermined portion PP extends along the edge 520 in the vicinity of the edge 520. This makes it possible to secure a large area on the substrate 500C where electronic components can be placed, and also increases the length of the slit 514C, thereby increasing the current loop formed around the slit 514C and increasing the communication distance of the antenna device 10C.

[0082] As shown in Figure 27, the antenna device 10C further includes a capacitor 600 that constitutes part of the resonant circuit.

[0083] Referring to Figure 27, the capacitor 600, together with the path circling around the opening 512 and slit 514C in the conductor portion 510C, constitutes a current loop path. That is, the capacitor 600, together with the path circling around the opening 512 and slit 514C in the conductor portion 510C, constitutes a resonant circuit. The resonant frequency of this resonant circuit is the communication frequency band of the antenna device 10C. As shown in Figure 27, the capacitor 600 is mounted in the region between the edge 520 and the slit 514C on the substrate 500C. More specifically, the capacitor 600 is mounted in the region between the edge 520 and the second portion 5144 on the substrate 500C. Note that the placement of the capacitor 600 is not limited to the above location, and it may be placed anywhere on the conductor portion 510C as long as the capacitor 600 and the path circling around the opening 512 and slit 514C in the conductor portion 510C constitute a current loop path.

[0084] (Third embodiment) As shown in Figure 28, the antenna device 10D according to the third embodiment of the present invention comprises a substrate 500D and a coil antenna 100. The coil antenna 100 in this embodiment has the same structure as the coil antenna 100 in the first embodiment, and a detailed explanation is omitted. In addition, the same expressions as those in the first embodiment will be used below for direction and orientation in this embodiment.

[0085] As shown in Figure 28, the substrate 500D of this embodiment has a planar conductive portion 510D. More specifically, the conductive portion 510D is a ground conductor. Specifically, the substrate 500D has a conductive layer as the conductive portion 510D laminated on an insulating substrate such as a glass epoxy substrate.

[0086] As shown in Figure 28, the conductor portion 510D has an opening 512 and a slit 514D. The path encircling the opening 512 and slit 514D in the conductor portion 510D constitutes part of the resonant circuit. The opening 512 in this embodiment has the same structure as the opening 512 in the first embodiment, and a detailed explanation is omitted.

[0087] As shown in Figure 28, the slit 514D in this embodiment, like the opening 512, is a portion on the substrate 500D that does not have a conductive pattern. The slit 514D is connected to the opening 512. The slit 514D extends from the opening 512. The slit 514D extends from the opening 512 in the front-rear direction. The slit 514D does not communicate with the outside of the conductive portion 510D in a plane perpendicular to the vertical direction.

[0088] As shown in Figure 28, the width of the slit 514D is smaller than the diameter of the opening 512. However, the present invention is not limited to this, and the width of the slit 514D and the diameter of the opening 512 may be the same, or the width of the slit 514D may be larger than the diameter of the opening 512. Increasing the width of the slit 514D increases the current loop formed around the slit 514D, thereby increasing the communication distance of the antenna device 10D.

[0089] As shown in Figure 28, an additional opening 516 is further formed in the conductor portion 510D.

[0090] As shown in Figure 28, the additional opening 516 in this embodiment is a hole that penetrates the substrate 500D. That is, the additional opening 516 penetrates the substrate 500D in the vertical direction. However, the present invention is not limited thereto, and the additional opening 516 may be a portion on the substrate 500D that does not have a conductive pattern, similar to the opening 512. The additional opening 516 is located in front of the opening 512 in the front-rear direction. In a plane perpendicular to the vertical direction, the additional opening 516 is larger than the opening 512. The path that circumfers the additional opening 516 in the conductive portion 510D constitutes part of the resonant circuit. The slit 514D is connected to both the opening 512 and the additional opening 516.

[0091] As shown in Figure 28, an additional slit 518 is further formed in the conductor portion 510D.

[0092] As shown in Figure 28, the additional slit 518 in this embodiment, like the opening 512, is a portion on the substrate 500D that does not have a conductive pattern. The additional slit 518 is connected to the opening 512. The additional slit 518 extends from the opening 512. The additional slit 518 extends in the left-right direction. The additional slit 518 communicates with the outside of the conductive portion 510D in a plane perpendicular to the vertical direction. The opening 512, slit 514D, additional opening 516, and additional slit 518 are all connected to one another.

[0093] As shown in Figure 28, the width of the additional slit 518 is smaller than the diameter of the opening 512. However, the present invention is not limited to this, and the width of the additional slit 518 and the diameter of the opening 512 may be the same, or the width of the additional slit 518 may be larger than the diameter of the opening 512.

[0094] As shown in Figure 28, the substrate 500D has an edge 520.

[0095] As shown in Figure 28, edge 520 defines the outer edge of substrate 500D. That is, edge 520 defines the outer edge of substrate 500D in a direction perpendicular to the vertical direction. Slit 514D does not reach edge 520. Additional slit 518 extends toward edge 520. That is, additional slit 518 extends from opening 512 toward edge 520. Additional slit 518 reaches edge 520.

[0096] Referring to Figure 28, the coil antenna 100 is mounted on the substrate 500D such that it at least partially overlaps with the aperture 512 when viewed along the vertical direction perpendicular to the substrate 500D. The coil antenna 100 is mounted on the substrate 500D such that it does not overlap with the additional aperture 516 when viewed along the vertical direction. The coil antenna 100 is surface-mounted on the substrate 500D.

[0097] As shown in Figure 28, the antenna device 10D further includes a capacitor 600D that constitutes part of the resonant circuit.

[0098] Referring to Figure 28, the capacitor 600D, together with the path circling around the opening 512, additional opening 516, slit 514D, and additional slit 518 in the conductor portion 510D, constitutes a current loop path. That is, the capacitor 600D, together with the path circling around the opening 512, additional opening 516, slit 514D, and additional slit 518 in the conductor portion 510D, constitutes a resonant circuit. The resonant frequency of this resonant circuit is the communication frequency band of the antenna device 10D. The capacitor 600D is mounted on the substrate 500D so as to straddle the additional slit 518. Note that the placement of the capacitor 600D is not limited to the above location, and it may be placed anywhere in the conductor portion 510D as long as the capacitor 600D and the path circling around the opening 512, additional opening 516, slit 514D, and additional slit 518 in the conductor portion 510D constitute a current loop path.

[0099] (Fourth embodiment) As shown in Figure 29, the antenna device 10E according to the fourth embodiment of the present invention comprises a substrate 500E and a coil antenna 100. The coil antenna 100 in this embodiment has the same structure as the coil antenna 100 in the first embodiment, and a detailed explanation is omitted. In addition, the same expressions as those in the first embodiment will be used below for direction and orientation in this embodiment.

[0100] As shown in Figure 29, the substrate 500E of this embodiment has a planar conductive portion 510E. More specifically, the conductive portion 510E is a ground conductor. Specifically, the substrate 500E has a conductive layer as the conductive portion 510E laminated on an insulating substrate such as a glass epoxy substrate.

[0101] As shown in Figure 29, the conductor portion 510E has an opening 512 and a slit 514E. The path encircling the opening 512 and slit 514E in the conductor portion 510E constitutes part of the resonant circuit. The opening 512 in this embodiment has the same structure as the opening 512 in the first embodiment, and a detailed explanation is omitted.

[0102] As shown in Figure 29, the slit 514E in this embodiment, like the opening 512, is a portion on the substrate 500E that does not have a conductive pattern. The slit 514E is connected to the opening 512. The slit 514E extends to the left in the left-right direction from the opening 512, and then extends to the rear in the front-back direction. The slit 514E extends from the opening 512. The slit 514E does not communicate with the outside of the conductive portion 510E in a plane perpendicular to the vertical direction.

[0103] As shown in Figure 29, the width of the slit 514E is smaller than the diameter of the opening 512. However, the present invention is not limited to this, and the width of the slit 514E and the diameter of the opening 512 may be the same, or the width of the slit 514E may be larger than the diameter of the opening 512. Increasing the width of the slit 514E increases the current loop formed around the slit 514E, thereby increasing the communication distance of the antenna device 10E.

[0104] As shown in Figure 29, an additional opening 516 is further formed in the conductor portion 510E.

[0105] As shown in Figure 29, the additional opening 516 in this embodiment is a hole that penetrates the substrate 500E. That is, the additional opening 516 penetrates the substrate 500E in the vertical direction. However, the present invention is not limited thereto, and the additional opening 516 may be a portion of the substrate 500E that does not have a conductive pattern, similar to the opening 512. The additional opening 516 is located behind the opening 512 in the front-rear direction. In a plane perpendicular to the vertical direction, the additional opening 516 is larger than the opening 512. The path that circumfers the additional opening 516 in the conductive portion 510E constitutes part of the resonant circuit. The slit 514E is connected to both the opening 512 and the additional opening 516.

[0106] As shown in Figure 29, an additional slit 518 is further formed in the conductor portion 510E.

[0107] As shown in Figure 29, the additional slit 518 in this embodiment, like the opening 512, is a portion on the substrate 500E that does not have a conductive pattern. The additional slit 518 is connected to the additional opening 516. The additional slit 518 extends from the additional opening 516. The additional slit 518 extends in the left-right direction. The additional slit 518 communicates with the outside of the conductive portion 510E in a plane perpendicular to the vertical direction. The opening 512, slit 514E, additional opening 516, and additional slit 518 are all connected to one another.

[0108] As shown in Figure 29, the substrate 500E has an edge 520.

[0109] As shown in Figure 29, edge 520 defines the outer edge of substrate 500E. That is, edge 520 defines the outer edge of substrate 500E in a direction perpendicular to the vertical direction. Slit 514E does not reach edge 520. Additional slit 518 extends toward edge 520. That is, additional slit 518 extends toward edge 520 from additional opening 516. Additional slit 518 reaches edge 520.

[0110] Referring to Figure 29, the coil antenna 100 is mounted on the substrate 500E such that it at least partially overlaps with the aperture 512 when viewed along the vertical direction perpendicular to the substrate 500E. The coil antenna 100 is mounted on the substrate 500E such that it does not overlap with the additional aperture 516 when viewed along the vertical direction. The coil antenna 100 is surface-mounted on the substrate 500E.

[0111] As shown in Figure 29, the antenna device 10E further includes a capacitor 600E that constitutes part of the resonant circuit.

[0112] Referring to Figure 29, the capacitor 600E, together with the path circling around the opening 512, additional opening 516, slit 514E, and additional slit 518 in the conductor portion 510E, constitutes a current loop path. That is, the capacitor 600E, together with the path circling around the opening 512, additional opening 516, slit 514E, and additional slit 518 in the conductor portion 510E, constitutes a resonant circuit. The resonant frequency of this resonant circuit is the communication frequency band of the antenna device 10E. The capacitor 600E is mounted on the substrate 500E so as to straddle the additional slit 518. Note that the placement of the capacitor 600E is not limited to the above location, and it may be placed anywhere in the conductor portion 510E as long as the capacitor 600E and the path circling around the opening 512, additional opening 516, slit 514E, and additional slit 518 in the conductor portion 510E constitute a current loop path.

[0113] (Fifth embodiment) As shown in Figure 30, the antenna device 10F according to the fifth embodiment of the present invention comprises a substrate 500F and a coil antenna 100. The coil antenna 100 in this embodiment has the same structure as the coil antenna 100 in the first embodiment, and a detailed explanation is omitted. In addition, the same expressions as those in the first embodiment will be used below for direction and orientation in this embodiment.

[0114] As shown in Figure 30, the substrate 500F of this embodiment has a planar conductive portion 510F. More specifically, the conductive portion 510F is a ground conductor. Specifically, the substrate 500F has a conductive layer as the conductive portion 510F laminated on an insulating substrate such as a glass epoxy substrate.

[0115] As shown in Figure 30, the conductor portion 510F has an opening 512 and a slit 514F. The path encircling the opening 512 and slit 514F in the conductor portion 510F constitutes part of the resonant circuit. The opening 512 in this embodiment has the same structure as the opening 512 in the first embodiment, and a detailed explanation is omitted.

[0116] As shown in Figure 30, the slit 514F in this embodiment, like the opening 512, is a portion on the substrate 500F that does not have a conductive pattern. The slit 514F is connected to the opening 512. The slit 514F extends from the opening 512.

[0117] As shown in Figure 30, the width of the slit 514F is smaller than the diameter of the opening 512. However, the present invention is not limited to this, and the width of the slit 514F and the diameter of the opening 512 may be the same, or the width of the slit 514F may be larger than the diameter of the opening 512. Increasing the width of the slit 514F increases the current loop formed around the slit 514F, thereby increasing the communication distance of the antenna device 10F.

[0118] As shown in Figure 30, an additional opening 516 is further formed in the conductor portion 510F.

[0119] As shown in Figure 30, the additional opening 516 in this embodiment is a hole that penetrates the substrate 500F. That is, the additional opening 516 penetrates the substrate 500F in the vertical direction. However, the present invention is not limited thereto, and the additional opening 516 may be a portion of the substrate 500F that does not have a conductive pattern, similar to the opening 512. The additional opening 516 is located behind the opening 512 in the front-rear direction. In a plane perpendicular to the vertical direction, the additional opening 516 is larger than the opening 512. The path that circles around the additional opening 516 in the conductive portion 510F constitutes part of the resonant circuit. The slit 514F is connected to both the opening 512 and the additional opening 516.

[0120] As shown in Figure 30, an additional slit 518 is further formed in the conductor portion 510F.

[0121] As shown in Figure 30, the additional slit 518 in this embodiment, like the opening 512, is a portion on the substrate 500F that does not have a conductive pattern. The additional slit 518 is connected to the slit 514F. The additional slit 518 extends from the slit 514F in the left-right direction. The additional slit 518 communicates with the outside of the conductive portion 510F in a plane perpendicular to the vertical direction. In a plane perpendicular to the vertical direction, the slit 514F communicates with the outside of the conductive portion 510F via the additional slit 518. The opening 512, the slit 514F, the additional opening 516, and the additional slit 518 are all connected to each other.

[0122] As shown in Figure 30, the width of the additional slit 518 is the same as the width of the slit 514F. However, the present invention is not limited to this, and the width of the additional slit 518 may be smaller than or larger than the width of the slit 514F.

[0123] As shown in Figure 30, the substrate 500F has an edge 520.

[0124] As shown in Figure 30, edge 520 defines the outer edge of substrate 500F. That is, edge 520 defines the outer edge of substrate 500F in a direction perpendicular to the vertical direction. The additional slit 518 extends toward edge 520. That is, the additional slit 518 extends from slit 514F toward edge 520. The additional slit 518 reaches edge 520.

[0125] Referring to Figure 30, the coil antenna 100 is mounted on the substrate 500F such that it at least partially overlaps with the aperture 512 when viewed along the vertical direction perpendicular to the substrate 500F. The coil antenna 100 is mounted on the substrate 500F such that it does not overlap with the additional aperture 516 when viewed along the vertical direction. The coil antenna 100 is surface-mounted on the substrate 500F.

[0126] As shown in Figure 30, the antenna device 10F further includes a capacitor 600F that constitutes part of the resonant circuit.

[0127] Referring to Figure 30, the capacitor 600F, together with the path circling around the opening 512, additional opening 516, slit 514F, and additional slit 518 in the conductor portion 510F, constitutes a current loop path. That is, the capacitor 600F, together with the path circling around the opening 512, additional opening 516, slit 514F, and additional slit 518 in the conductor portion 510F, constitutes a resonant circuit. The resonant frequency of this resonant circuit is the communication frequency band of the antenna device 10F. The capacitor 600F is mounted on the substrate 500F so as to straddle the additional slit 518. Note that the placement of the capacitor 600F is not limited to the above location, and it may be placed anywhere on the conductor portion 510F as long as the capacitor 600F and the path circling around the opening 512, additional opening 516, slit 514F, and additional slit 518 in the conductor portion 510F constitute a current loop path.

[0128] Although the present invention has been described in detail with reference to embodiments above, the present invention is not limited thereto, and various modifications and changes are possible.

[0129] In the antenna devices 10 and 10C of the first and second embodiments described above, there was no portion corresponding to the additional opening 516 of the antenna devices 10D, 10E, and 10F of the third, fourth, and fifth embodiments. However, the present invention is not limited thereto. That is, even in the antenna devices 10 and 10C, an additional opening 516 that constitutes part of the slits 514 and 514C may be provided. [Explanation of symbols]

[0130] 10, 10C, 10D, 10E, 10F Antenna Equipment 100, 100A, 100B coil antenna 200 coils 210 Top 220 bottom end 230 Outer circumference 240 inner circumference 300, 300A, 300B Magnetic Cores 310 Core 320,320B upper part 340 Side 400 terminals 500, 500C, 500D, 500E, 500F circuit boards 510, 510C, 510D, 510E, 510F Conductor section 512 Opening 514, 514C, 514D, 514E, 514F Slit 5142 Part 1 5144 Part 2 5146 Part 3 516 Additional opening 518 Additional slit 520 Edge 600, 600D, 600E, 600F Capacitors 700, 700A resin mold AX winding shaft PP designated area SR specific area

Claims

1. An antenna device comprising a substrate and a coil antenna, The substrate has a planar conductive portion, The aforementioned conductor portion has an opening and a slit formed therein. The path encircling the opening and the slit in the conductor portion constitutes part of the resonant circuit. The slit is connected to the opening, The coil antenna is mounted on the substrate such that it at least partially overlaps the opening when viewed along the vertical direction perpendicular to the substrate. The coil antenna comprises a coil and a magnetic core. The coil has a winding shaft that extends in the vertical direction, The magnetic core partially constitutes the magnetic path of the coil, The magnetic core is located in a region excluding a specific region directly below the coil. The magnetic core has at least a central core, The core is located at least partially inside the coil, The aforementioned conductor portion is further formed with additional openings. The path encircling the additional opening in the conductor portion constitutes a part of the resonant circuit. The slit is connected to both the opening and the additional opening. Antenna device.

2. The antenna device according to claim 1, The substrate has an edge, The slit extends toward the edge. Antenna device.

3. The antenna device according to claim 1, The coil antenna is mounted on the substrate in such a way that it does not overlap with the additional opening when viewed along the vertical direction. Antenna device.

4. The antenna device according to claim 1, The substrate has an edge, The aforementioned conductor portion is further formed with additional slits. The additional slit extends toward the edge, The antenna device further includes a capacitor that constitutes part of the resonant circuit. The capacitor is mounted on the substrate so as to straddle the additional slit. Antenna device.

5. The antenna device according to claim 4, The opening, the slit, the additional opening, and the additional slit are all connected to one another. Antenna device.

6. The antenna device according to claim 1, The core extends below the lower end of the coil in the vertical direction. Antenna device.

7. The antenna device according to claim 1, The core extends above the upper end of the coil in the vertical direction. Antenna device.

8. The antenna device according to claim 7, The aforementioned magnetic core further has an upper part, The upper part extends from the core toward the outer circumference of the coil, The upper part overlaps with the coil when viewed from the vertical direction. Antenna device.

9. The antenna device according to claim 8, The magnetic core further has sides, The aforementioned side portion is located outside the coil in a plane perpendicular to the vertical direction, The side portion extends downward in the vertical direction from the upper part. Antenna device.

10. The antenna device according to claim 1, The substrate has an edge, The slit has a predetermined portion, The predetermined portion extends along the edge in the vicinity of the edge. Antenna device.

11. The antenna device according to claim 10, The antenna device further includes a capacitor that constitutes part of the resonant circuit. The capacitor is mounted in the region between the edge and the slit on the substrate. Antenna device.

12. The antenna device according to claim 10, The slit has a first portion and a second portion, The first portion extends from the opening toward the edge, The second portion extends from the first portion in a direction intersecting the first portion, The second part is the predetermined part. Antenna device.

13. The antenna device according to claim 12, The aforementioned slit further comprises a third portion, The third portion extends from the second portion in a direction intersecting the second portion. Antenna device.

14. The antenna device according to claim 1, When the cross-sectional area of ​​the inner circumference of the coil is S1 and the area of ​​the opening is S2, the condition 1 ≤ S2 / S1 ≤ 2 is satisfied. Antenna device.

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