Antenna module

Abstract

An antenna module (1) comprises: a transparent conductive film (2); and a flexible wiring board (3) connected to the transparent conductive film (2). The transparent conductive film (2) includes: a first base material (41) having a first surface (41a) and a second surface (41b); an antenna (10); a first ground layer (51) provided on the second surface (41b); and a second ground layer (52) provided on the first surface (41a). The flexible wiring board (3) includes: a second base material (42) having a third surface (42a) and a fourth surface (42b); and a third ground layer (53) provided on the third surface (42a). The second ground layer (52) and the third ground layer (53) are electrically connected to one another. The first ground layer (51) and the second ground layer (52) are electrically connected to one another via one or more vias (60) provided to the first base material (41).

Description

Antenna Module

[0001] The present disclosure relates to an antenna module including a transparent conductive film.

[0002] Transparent conductive films having fine conductive lines formed on a transparent substrate are known. One such type of transparent conductive film is a film antenna having an antenna formed from fine conductive lines (see, for example, Patent Document 1). Film antennas are used in mobile devices requiring an antenna, such as smartphones or tablet devices. The antenna in a film antenna is formed from fine conductive lines having a line width of 100 μm or less, which is difficult to detect with the naked eye. This allows the antenna to be made transparent, so that the antenna can be easily mounted on a mobile device even if the mobile device is made thinner and lighter, reducing the space available for component placement.

[0003] International Publication No. 2021 / 229994 Special Publication No. 2021-528902

[0004] In a transparent conductive film having an antenna, an antenna and a signal line connected to the antenna are formed on one surface of a transparent substrate, and a ground layer is formed on the other surface of the transparent substrate. In a transparent conductive film having an antenna, crosstalk occurring between the signal lines is an issue.

[0005] Furthermore, in order to connect the transparent conductive film to an external device such as a control circuit, a flexible wiring board is connected to an end of the transparent conductive film (see, for example, Patent Document 2). An antenna module is constructed by connecting the transparent conductive film having an antenna to the flexible wiring board.

[0006] However, the antenna module structure disclosed in Patent Document 2 has a problem in that the return current generated in the ground layer of the transparent conductive film does not flow to the flexible wiring board, which worsens crosstalk. On the other hand, if a separate component is installed to suppress crosstalk, costs increase.

[0007] One aspect of the antenna module according to the present disclosure includes a transparent conductive film and a wiring board connected to the transparent conductive film, wherein the transparent conductive film includes a first substrate having a first surface and a second surface facing the first surface, an antenna provided on the first surface, a first signal terminal provided on the first surface and electrically connected to the antenna, a first ground layer provided on the second surface, and a second ground layer provided on the first surface, and the wiring board includes a second substrate, a third ground layer provided on the second substrate, and a second signal terminal provided on the second substrate, at least a portion of the wiring board is disposed facing the transparent conductive film, the first signal terminal and the second signal terminal are electrically connected, the second ground layer and the third ground layer are electrically connected, and the first ground layer and the second ground layer are electrically connected via one or more vias provided in the first substrate.

[0008] Another aspect of the antenna module according to the present disclosure includes a transparent conductive film and a wiring board connected to the transparent conductive film, wherein the transparent conductive film includes a first substrate, an antenna provided on the first substrate, a first signal terminal provided on the first substrate and electrically connected to the antenna, a first ground layer provided on the first substrate, a second ground layer provided on the first substrate that is a layer different from the first ground layer, and a connection line electrically connected to the first ground layer and electrically connecting the first ground layer and the second ground layer, and the wiring board includes a second substrate, a third ground layer provided on the second substrate and electrically connected to the second ground layer, and a second signal terminal provided on the second substrate and electrically connected to the first signal terminal, and at least a portion of the second substrate faces the first substrate.

[0009] According to the present disclosure, crosstalk can be suppressed without increasing the number of parts.

[0010] 1 is a diagram schematically illustrating a configuration of an antenna module according to a first embodiment. It is an enlarged view of an end portion of the antenna module in region II surrounded by a dashed line in FIG. 1. It is a cross-sectional view taken along line A-A in FIG. 2. It is a cross-sectional view taken along line B-B in FIG. 2. It is an enlarged view of a joint portion between a transparent conductive film and a flexible wiring board in an antenna module of a comparative example. It is a cross-sectional view taken along line A-A in FIG. 4. It is a cross-sectional view taken along line B-B in FIG. 4. It is a diagram illustrating measurement results of near-end crosstalk (NEXT) of the antenna module according to the first embodiment and an antenna module of a comparative example. It is a diagram illustrating measurement results of far-end crosstalk (FEXT) of the antenna module according to the first embodiment and an antenna module of a comparative example. It is an enlarged view of a joint portion between a transparent conductive film and a flexible wiring board in an antenna module according to a modified example of the first embodiment. It is a cross-sectional view taken along line A-A in FIG. 7. It is a cross-sectional view taken along line B-B in FIG. 7. It is an enlarged view of a joint portion between a transparent conductive film and a flexible wiring board in an antenna module according to a second embodiment. It is a cross-sectional view taken along line A-A in FIG. 9. It is a cross-sectional view taken along line B-B in FIG. 9.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, the arrangement and connection of the components, processes (steps), and the order of the processes shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims that represent the superordinate concept of the present disclosure will be described as optional components.

[0012] Note that each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, the scales and the like do not necessarily match in each figure. Furthermore, in each figure, substantially the same configuration is assigned the same reference numeral, and duplicate explanations are omitted or simplified. Furthermore, in this specification, the terms "up" and "down" do not necessarily refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition.

[0013] (Embodiment 1) An antenna module 1 according to embodiment 1 will be described using Figures 1 to 3B. Figure 1 is a diagram schematically illustrating the configuration of the antenna module 1 according to embodiment 1. In Figure 1, (a) is a plan view of the antenna module 1, (b) is a cross-sectional view taken along line b-b in (a), and (c) is a cross-sectional view taken along line c-c in (a). Figure 2 is an enlarged view of region II surrounded by a dashed line in Figure 1, illustrating the joint between the transparent conductive film 2 and the flexible wiring board 3 in the antenna module 1. In Figure 2, the end of the antenna module 1 in region II is illustrated separately as an end of the transparent conductive film 2 and an end of the flexible wiring board 3. Specifically, (a) in Figure 2 illustrates the end of the transparent conductive film 2 in region II, and (b) in Figure 2 illustrates the end of the flexible wiring board 3 in region II. Furthermore, Figure 3A is a cross-sectional view taken along line A-A in Figure 2, and Figure 3B is a cross-sectional view taken along line B-B in Figure 2. In addition, the second ground layer 52 is not shown in FIG.

[0014] The antenna module 1 is an example of an antenna device having an antenna for emitting radio waves into space and receiving radio waves from space. The antenna module 1 can be used, for example, in devices for 3G to 5G communications. The communication frequency of the antenna module 1 is, for example, a predetermined frequency band of 0.5 GHz to 30 GHz. For example, the communication frequency of the antenna module 1 is the 3.7 GHz band, the 4.5 GHz band, or the 28 GHz band.

[0015] As shown in FIG. 1( a ), the antenna module 1 includes a transparent conductive film 2 and a flexible wiring board 3 connected to the transparent conductive film 2 .

[0016] The transparent conductive film 2 is an example of a wiring substrate on which conductive lines of a predetermined shape are formed. Specifically, the transparent conductive film 2 is a flexible film-like wiring substrate that is transparent enough to allow the other side to be seen through. In this embodiment, the transparent conductive film 2 is a film antenna having an antenna made of conductive lines.

[0017] A flexible wiring board 3 is connected to the transparent conductive film 2. The flexible wiring board 3 may be a wiring board having only conductive lines formed thereon and having a wiring function only, or may be a COF (chip on film) on which a semiconductor chip such as a driver IC is mounted.

[0018] As shown in FIG. 1A, the transparent conductive film 2 has a first region, an effective region 2a (active region), and a second region, an ineffective region 2b (inactive region), which is different from the effective region 2a. The effective region 2a is a region located inside the ineffective region 2b. The ineffective region 2b is a region located outside the effective region 2a. In this embodiment, the ineffective region 2b surrounds the effective region 2a. Specifically, the ineffective region 2b is a frame-shaped region (frame region) surrounding the effective region 2a. Therefore, the effective region 2a is a rectangular region. The ineffective region 2b is a peripheral region located at the outer peripheral edge of the transparent conductive film 2.

[0019] The effective area 2a is a transparent area, and the ineffective area 2b is a non-transparent area. Therefore, for example, when the transparent conductive film 2 is placed on a display device of a mobile terminal, the effective area 2a is an area (view area) that can be seen by a user of the mobile terminal, and the ineffective area 2b is an area that is not visible to the user because it is covered by the housing of the mobile terminal or the like. The user can view an image displayed on the display device through the effective area 2a, which is a transparent area, and can operate the mobile terminal by touching the effective area 2a with their finger.

[0020] The effective area 2a is an antenna area in which the antenna 10 (antenna radiation portion) is provided. The antenna 10 is made of conductive wire. In this embodiment, the antenna 10 is a microstrip antenna (patch antenna) made of a microstrip line, which is a fine metal wire with a line width on the order of micrometers. Specifically, the line width of the metal wire that makes up the antenna 10 is 100 μm or less. As an example, the line width of the metal wire that makes up the antenna 10 is 1 μm to 30 μm. The metal wire that makes up the antenna 10 is formed in a predetermined pattern. In this embodiment, the conductive wire that makes up the antenna 10 is formed in a mesh shape. In other words, the antenna 10 is a mesh antenna.

[0021] In this embodiment, the antenna 10 is an assembly of multiple antenna elements 10a. This allows the radiation intensity of the antenna 10 to be increased and allows it to support multiple frequency bands. The multiple antenna elements 10a are formed in different regions within the effective area 2a. In this embodiment, each of the multiple antenna elements 10a is formed in a respective one of multiple island regions 2a1 that are partitioned into island-like regions within the effective area 2a. The multiple island regions 2a1 are formed in a matrix. As an example, the multiple island regions 2a1 are partitioned into 16 regions with 4 rows and 4 columns, as shown in FIG. 1A. In each island region 2a1, the antenna elements 10a are formed in a mesh pattern.

[0022] As shown in the enlarged view of FIG. 1A , the mesh-shaped antenna element 10a includes a plurality of first directional lines extending in a first direction and a plurality of second directional lines extending in a second direction intersecting the first direction. In this embodiment, the first directional lines and the second directional lines are not perpendicular to each other, but they may be perpendicular to each other. Furthermore, each of the plurality of first directional lines is parallel to each other. Similarly, each of the plurality of second directional lines is parallel to each other. The plurality of first directional lines and the plurality of second directional lines are formed on the same plane. Therefore, the plurality of first directional lines and the plurality of second directional lines are integrated at the intersections where the first directional lines and the second directional lines intersect. The first directional lines and the second directional lines may intersect at an intersection such that the first directional lines and the second directional lines do not contact each other at the intersections.

[0023] Furthermore, a first signal line 21 and a first signal terminal 31 are provided in the ineffective region 2b. Each of the first signal line 21 and the first signal terminal 31 is electrically connected to the antenna 10. Specifically, the antenna 10 and the first signal terminal 31 are electrically connected via the first signal line 21. In other words, the first signal line 21 is a connection wiring for connecting the antenna 10 and the first signal terminal 31. Furthermore, the first signal line 21 connected to the antenna 10 functions as a transmission path. Note that the first signal terminal 31 may be a part of the first signal line 21. For example, the first signal terminal 31 may be one end of a conductive wire that constitutes the first signal line 21.

[0024] A plurality of first signal lines 21 are provided. Each of the plurality of first signal lines 21 is connected to each of the plurality of antenna elements 10a. That is, the plurality of first signal lines 21 and the plurality of antenna elements 10a are provided in a one-to-one correspondence. Each of the plurality of first signal lines 21 is formed in a predetermined shape in the ineffective region 2b. The ineffective region 2b is a wiring region in which the first signal lines 21 are routed.

[0025] A plurality of first signal terminals 31 are provided to be connected to the first signal line 21. The number of first signal terminals 31 also corresponds to the number of antenna elements 10a. In other words, there is a one-to-one correspondence between the first signal terminals 31 and the antenna elements 10a.

[0026] The multiple first signal terminals 31 are provided in a connection terminal portion 31a in the ineffective region 2b. Therefore, the multiple first signal lines 21 connected to the multiple first signal terminals 31 are concentrated in the connection terminal portion 31a. Each of the multiple first signal terminals 31 is formed in an elongated shape and extends toward the end of the transparent conductive film 2. The multiple first signal terminals 31 are arranged in parallel.

[0027] The connection terminal portion 31a, which is an area where a plurality of first signal terminals 31 are provided, is a pad portion to which the flexible wiring board 3 is connected. The flexible wiring board 3 is connected to the ineffective area 2b of the transparent conductive film 2. Specifically, the flexible wiring board 3 is connected to the transparent conductive film 2 at the connection terminal portion 31a in the ineffective area 2b.

[0028] The flexible wiring board 3 and the transparent conductive film 2 are joined by a conductive joining member (not shown) such as an anisotropic conductive film (ACF) or solder. In this embodiment, the flexible wiring board 3 and the transparent conductive film 2 are joined by the anisotropic conductive film. As shown in (a) of FIG. 1, an ACF region 4a surrounded by a dashed line is a region where the anisotropic conductive film is disposed.

[0029] The flexible wiring board 3 has a second signal line 22 and a second signal terminal 32. The second signal line 22 is made of a conductive wire such as a metal wire, and is electrically connected to the second signal terminal 32. As an example, the second signal line 22 and the second signal terminal 32 are made of copper. The second signal terminal 32 may be a part of the second signal line 22. For example, the second signal terminal 32 may be one end of the conductive wire that constitutes the second signal line 22.

[0030] A plurality of second signal lines 22 and a plurality of second signal terminals 32 are provided. The plurality of second signal lines 22 and the plurality of second signal terminals 32 are provided in a one-to-one correspondence. The plurality of second signal lines 22 are arranged in parallel. The plurality of second signal terminals 32 are also arranged in parallel.

[0031] 1(a) and 1(b), the plurality of second signal terminals 32 face the plurality of first signal terminals 31 of the transparent conductive film 2. The plurality of second signal terminals 32 and the plurality of first signal terminals 31 may be the same in number and provided in one-to-one correspondence, or they may not be the same in number.

[0032] The flexible wiring board 3 is provided with a connector 5. The connector 5 is provided at an end of the second signal line 22 opposite to the second signal terminal 32 side. A connector of an external device such as a control circuit is connected to the connector 5. The plurality of second signal terminals 32 are electrically connected to the external device such as the control circuit via the connector 5.

[0033] As shown in FIGS. 1 to 3B, the transparent conductive film 2 has a first substrate 41, a first ground layer 51, and a second ground layer 52.

[0034] 1B and 1C, the first substrate 41 has a first surface 41a and a second surface 41b facing away from the first surface 41a. In other words, the second surface 41b is the surface opposite to the first surface 41a. In FIGS. 1B and 1C, the first surface 41a is the upper surface of the first substrate 41, and the second surface 41b is the lower surface of the first substrate 41.

[0035] The first base material 41 has a base material layer 411 and a resin layer 412 laminated on the base material layer 411. In (b) and (c) of Figure 1, the resin layer 412 is disposed above the base material layer 411. In other words, the base material layer 411 is located below the resin layer 412. The upper surface of the resin layer 412 is a first surface 41a which is the upper surface of the first base material 41, and the lower surface of the base material layer 411 is a second surface 41b which is the lower surface of the first base material 41.

[0036] The antenna 10, the first signal line 21, and the first signal terminal 31 are provided on the first surface 41a of the first base material 41. Specifically, the antenna 10, the first signal line 21, and the first signal terminal 31 are provided on the resin layer 412 of the first base material 41. An insulating film may be formed to cover the antenna 10, the first signal line 21, and the first signal terminal 31.

[0037] The substrate layer 411 is a substrate that serves as a base film for the transparent conductive film 2. Specifically, the substrate layer 411 is a flexible sheet-like film substrate. The substrate layer 411 is a light-transmitting substrate that is transparent to visible light. Specifically, the substrate layer 411 is a transparent substrate with such high transmittance that the other side can be seen through it.

[0038] The base material layer 411 is made of a resin material. In this embodiment, the base material layer 411 is made of a translucent resin material. Specifically, the base material layer 411 is made of a transparent resin material. The base material layer 411 is also an insulating substrate made of an insulating material. Therefore, the base material layer 411 is made of a transparent insulating resin material. The base material layer 411 is a flat, planar plate with a constant thickness. The top view shape of the base material layer 411 is, for example, rectangular, but is not limited to this.

[0039] Examples of the light-transmitting resin material that can be used to form the base layer 411 include polyethylene terephthalate (PET) resin, polyimide (PI) resin, polyethylene naphthalate (PEN) resin, cycloolefin resin, polycarbonate resin, and acrylic resin. In this embodiment, the base layer 411 is a transparent PET film made of PET. Alternatively, a transparent glass substrate may be used as the base layer 411.

[0040] The resin layer 412 is located above the base material layer 411. In the present embodiment, the resin layer 412 is laminated on one surface of the base material layer 411. Specifically, the resin layer 412 is formed directly on the base material layer 411. Therefore, the upper surface of the base material layer 411 is in contact with the lower surface of the resin layer 412.

[0041] The resin layer 412 is an insulating layer made of an insulating resin material. In the present embodiment, the resin layer 412 is made of an insulating resin material having light-transmitting properties. Specifically, the resin layer 412 is made of a transparent insulating resin material. The resin material making up the resin layer 412 is a thermosetting resin or an ultraviolet-curing resin. Specifically, the resin material making up the resin layer 412 may be, for example, a PET resin, a polyimide resin, a cycloolefin resin, a polycarbonate resin, or an acrylic resin.

[0042] The resin layer 412 is provided with the conductive wires that make up the antenna 10, the first signal line 21, and the first signal terminal 31. The conductive wires that make up the antenna 10 have a smaller line width than the first signal line 21. In other words, the line width of the first signal line 21 is larger than the line width of the conductive wires that make up the antenna 10. This allows the resistance of the first signal line 21 to be reduced. As an example, the line width of the first signal line 21 is 5 μm to 200 μm, and is 20 μm in this embodiment.

[0043] The conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 may be made of the same metal material. For example, the conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 may be copper wiring mainly made of copper. Furthermore, the conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 may be formed in the same process. However, the conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 may be made of different metal materials or may be formed in different processes.

[0044] The conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 are embedded in grooves provided in resin layer 412. The conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 are embedded in the grooves of resin layer 412 so that their upper surfaces are exposed.

[0045] The grooves provided in the resin layer 412 are linear recesses formed so as to indent the surface of the resin layer 412. The resin layer 412 with the grooves provided therein is formed by an imprinting method. That is, the resin layer 412 is an imprinted layer. In this case, the resin layer 412 with the grooves provided therein can be formed by pressing a die member (mold) having protrusions corresponding to the grooves against the resin layer 412. Note that the resin layer 412 with the grooves can also be formed by a method other than the imprinting method. Specifically, the resin layer 412 with the grooves provided therein can be formed by forming a flat resin layer 412 and then forming the grooves in the resin layer 412. For example, the grooves can be formed by cutting out the surface of the flat resin layer 412 using a laser scriber or the like.

[0046] 1B and 1C, the first ground layer 51 is provided on the second surface 41b of the first substrate 41. Specifically, the first ground layer 51 is provided on the surface of the substrate layer 411 of the first substrate 41 opposite to the resin layer 412 side.

[0047] The first ground layer 51 faces the antenna 10 provided in the effective area 2a. Therefore, the first ground layer 51 is provided in the effective area 2a. In this embodiment, the first ground layer 51 faces all of the antenna elements 10a. In other words, in a plan view, the first ground layer 51 encompasses the entire antenna 10 and overlaps all of the multiple antenna elements 10a.

[0048] The first ground layer 51 is provided not only in the effective area 2 a but also in the ineffective area 2 b. For example, the first ground layer 51 may be provided over the entire effective area 2 a and the entire ineffective area 2 b. In this case, the first ground layer 51 may be a solid film formed over the entire second surface 41 b of the first substrate 41.

[0049] The first ground layer 51 provided in the ineffective region 2b overlaps the first signal terminal 31 as shown in Fig. 1B, and also overlaps the first signal line 21 as shown in Fig. 1C. In other words, in a plan view, the first ground layer 51 overlaps both the first signal terminal 31 and the first signal line 21.

[0050] 2 and 3A, the second ground layer 52 is provided on the first surface 41a of the first substrate 41. Specifically, the second ground layer 52 is provided on the surface of the resin layer 412 of the first substrate 41 opposite the substrate layer 411 side. As shown in Fig. 3A, in this embodiment, the second ground layer 52 is embedded in a groove provided in the resin layer 412, similar to the first signal terminal 31. The second ground layer 52 is embedded in the groove of the resin layer 412 so that the upper surface thereof is exposed.

[0051] 2A, the second ground layer 52 is provided in the ineffective region 2b. Specifically, the second ground layer 52 is provided in the ACF region 4a in the ineffective region 2b. Therefore, the second ground layer 52 is provided at the end of the first substrate 41 on the flexible wiring board 3 side. In this embodiment, the second ground layer 52 has an elongated shape and is formed so as to extend inward from the edge 41c of the first substrate 41.

[0052] The second ground layer 52 is located to the side of the first signal terminal 31. In this embodiment, a plurality of second ground layers 52 are provided, and the second ground layers 52 and the first signal terminals 31 are provided alternately. In other words, among the plurality of second ground layers 52, there is one or more second ground layers 52 located between two adjacent first signal terminals 31. Conversely, among the plurality of first signal terminals 31, there is one or more first signal terminals 31 located between two adjacent second ground layers 52.

[0053] The first ground layer 51 and the second ground layer 52 are made of a conductive material such as metal. For example, the first ground layer 51 and the second ground layer 52 are copper layers made of copper. The conductive material that makes up the first ground layer 51 and the conductive material that makes up the second ground layer 52 may be the same or different.

[0054] A specific voltage such as a ground potential (earth potential) may be applied to the first ground layer 51 and the second ground layer 52, but no specific voltage may be applied thereto. In other words, the first ground layer 51 and the second ground layer 52 may be in an electrically floating state.

[0055] 3A , the first ground layer 51 and the second ground layer 52 are electrically connected via one or more vias 60 provided in the first substrate 41. The vias 60 are connected to the first ground layer 51 and the second ground layer 52. The vias 60 function as connecting lines that electrically connect the first ground layer 51 and the second ground layer 52. The vias 60 are provided in through holes that penetrate the first substrate 41. Specifically, the vias 60 are provided in through holes that penetrate the substrate layer 411 and the resin layer 412. Note that the vias 60 are, for example, via holes, but may also be embedded vias that are formed to fill through holes provided in the first substrate 41.

[0056] In a plan view, the vias 60 are provided at positions overlapping with the second ground layers 52. The vias 60 are connected to each of the plurality of second ground layers 52 and are also connected to each of the plurality of first ground layers 51. Furthermore, a plurality of vias 60 are provided in each second ground layer 52.

[0057] In each second ground layer 52, the multiple vias 60 include first vias 61 and second vias 62. The first vias 61 are end vias located at the end of the first substrate 41 of the second ground layer 52. The second vias 62 are horizontal vias located to the sides of the first signal terminals 31 of the second ground layer 52. In each second ground layer 52, the first vias 61 are arranged in a row along the end edge 41 c of the first substrate 41, and the second vias 62 are arranged in a row along the longitudinal direction of the first signal terminals 31 (the longitudinal direction of the second ground layer 52). In each second ground layer 52, the second vias 62 are arranged in a row along the side surfaces of the second ground layer 52 at both ends of the second ground layer 52 in the width direction.

[0058] As shown in FIGS. 1 to 3B, the flexible wiring board 3 has a second substrate 42 and a third ground layer 53 .

[0059] 3A and 3B, the second substrate 42 has a third surface 42a and a fourth surface 42b facing away from the third surface 42a. In other words, the fourth surface 42b is the surface opposite to the third surface 42a. In FIG. 3A and 3B, the third surface 42a is the lower surface of the second substrate 42, and the fourth surface 42b is the upper surface of the second substrate 42.

[0060] The second substrate 42 is a substrate that serves as the base film of the flexible wiring board 3. Specifically, the second substrate 42 is a flexible sheet-like film substrate. The second substrate 42 is a base layer made of an insulating resin material and is a resin layer. For example, the second substrate 42 is made of polyimide resin, polyester resin, or the like. The second substrate 42 may or may not be light-transmitting.

[0061] In the flexible wiring board 3, the second signal line 22 and the second signal terminal 32 are provided on the third surface 42a of the second base material 42. An insulating film may be formed to cover the second signal line 22 and the second signal terminal 32.

[0062] The second signal line 22 and the second signal terminal 32 may be made of the same metal material. For example, the second signal line 22 and the second signal terminal 32 may be copper wiring mainly made of copper. The second signal line 22 and the second signal terminal 32 may be formed in the same process. However, the second signal line 22 and the second signal terminal 32 may be made of different metal materials or may be formed in different processes.

[0063] The second signal lines 22 and the second signal terminals 32 are embedded in grooves provided in the second substrate 42, but are not limited to this. The second signal lines 22 and the second signal terminals 32 may be formed in a predetermined pattern on the surface of the second substrate 42.

[0064] 3A , the third ground layer 53 is provided on the third surface 42a of the second substrate 42, similar to the second signal line 22 and the second signal terminal 32. The third ground layer 53 is embedded in a groove provided in the second substrate 42. Specifically, the third ground layer 53 is embedded in the groove of the second substrate 42 so that the surface is exposed. Note that the third ground layer 53 does not have to be embedded in the groove of the second substrate 42. In this case, the third ground layer 53 is formed on the surface of the second substrate 42.

[0065] The third ground layer 53 is provided at the end of the second base material 42 on the transparent conductive film 2 side. In the present embodiment, the second ground layer 52 has an elongated shape and is formed so as to extend inward from the edge 42 c of the second base material 42.

[0066] The third ground layer 53 is located to the side of the second signal terminal 32. In this embodiment, a plurality of third ground layers 53 are provided, and the third ground layers 53 and the second signal terminals 32 are provided alternately. In other words, among the plurality of third ground layers 53, there is one or more third ground layers 53 located between two adjacent second signal terminals 32. Conversely, among the plurality of second signal terminals 32, there is one or more second signal terminals 32 located between two adjacent third ground layers 53.

[0067] In a plan view, the third ground layer 53 overlaps with the second ground layer 52 of the transparent conductive film 2. That is, as shown in Fig. 3A, the third ground layer 53 faces the second ground layer 52. In the present embodiment, the shape of the third ground layer 53 in a plan view is the same as the shape of the second ground layer 52 in a plan view, but is not limited to this.

[0068] The third ground layer 53 is made of a conductive material such as a metal. For example, the third ground layer 53 is a copper layer made of copper. The conductive material of the third ground layer 53 may be the same as or different from the conductive materials of the first ground layer 51 and the second ground layer 52 in the transparent conductive film 2.

[0069] A specific voltage such as a ground potential (earth potential) may be applied to the third ground layer 53, but no specific voltage may be applied to the third ground layer 53. In other words, the third ground layer 53 may be in an electrically floating state.

[0070] The flexible wiring board 3 is connected to the transparent conductive film 2 with the third surface 42a of the second substrate 42 facing the first surface 41a of the first substrate 41 of the transparent conductive film 2. In this case, as described above, the transparent conductive film 2 and the flexible wiring board 3 are joined with a conductive bonding member such as an anisotropic conductive film. This electrically connects the first signal terminal 31 of the transparent conductive film 2 and the second signal terminal 32 of the flexible wiring board 3. Therefore, although not shown, a conductive bonding member such as an anisotropic conductive film is interposed between the first signal terminal 31 and the second signal terminal 32.

[0071] Furthermore, by joining the transparent conductive film 2 and the flexible wiring board 3 with a conductive bonding member such as an anisotropic conductive film, the second ground layer 52 of the transparent conductive film 2 and the third ground layer 53 of the flexible wiring board 3 are also electrically connected. Furthermore, by electrically connecting the third ground layer 53 to the second ground layer 52, the third ground layer 53 is also electrically connected to the first ground layer 51, which is connected to the second ground layer 52 via the via 60. Next, the effects of the antenna module 1 according to this embodiment will be described in comparison with the antenna module 1X of the comparative example using FIGS. 4, 5A, and 5B. FIG. 4 is an enlarged view of the bonded portion between the transparent conductive film 2X and the flexible wiring board 3 in the antenna module 1X of the comparative example. In FIG. 4, (a) shows the end of the transparent conductive film 2X, and (b) shows the end of the flexible wiring board 3. FIG. 5A is a cross-sectional view taken along line A-A in FIG. 4, and FIG. 5B is a cross-sectional view taken along line B-B in FIG. 4. Note that FIG. 4 corresponds to the enlarged view of FIG. 2.

[0072] As shown in FIGS. 4, 5A, and 5B, the antenna module 1X of the comparative example differs from the antenna module 1 according to the first embodiment in that the transparent conductive film 2X does not have vias 60 provided therein.

[0073] In the antenna module 1X of the comparative example configured in this manner, the second ground layer 52 of the transparent conductive film 2X and the third ground layer 53 of the flexible wiring board 3 are electrically connected, but the first ground layer 51 of the transparent conductive film 2X is not connected to either the second ground layer 52 or the third ground layer 53. For this reason, the return current generated in the first ground layer 51 when a signal is transmitted from the flexible wiring board 3 to the transparent conductive film 2X does not flow to the flexible wiring board 3. As a result, crosstalk occurring between signal lines in the antenna module 1X worsens.

[0074] In contrast, in the antenna module 1 according to this embodiment, as shown in FIG. 3A, the second ground layer 52 of the transparent conductive film 2 and the third ground layer 53 of the flexible wiring board 3 are electrically connected, and in the transparent conductive film 2, the first ground layer 51 and the second ground layer 52 are electrically connected via a via 60 provided in the first substrate 41.

[0075] With this configuration, a return current generated in the first ground layer 51 when a signal is transmitted from the flexible wiring board 3 to the transparent conductive film 2 flows through the via 60 to the second ground layer 52, as shown by the arrow in Figure 3A. As a result, the return current flows through the second ground layer 52 to the third ground layer 53 of the flexible wiring board 3. In this way, in the antenna module 1, a path for the return current from the transparent conductive film 2 to the flexible wiring board 3 can be secured, thereby effectively suppressing the deterioration of crosstalk that occurs between signal lines.

[0076] As described above, according to the antenna module 1 of this embodiment, crosstalk can be suppressed without mounting a separate component solely for the purpose of suppressing crosstalk. In other words, crosstalk can be suppressed without increasing the number of components.

[0077] In addition, in the antenna module 1 according to this embodiment, a plurality of vias 60 are provided.

[0078] This configuration allows the return current generated in the first ground layer 51 to be transmitted to the second ground layer 52 efficiently.

[0079] In this case, the multiple vias 60 include a first via 61 (end via) located at the end of the first substrate 41 in the second ground layer 52 .

[0080] In this way, by extending the second ground layer 52 to the end of the first substrate 41 and providing the first via 61 at the end of the first substrate 41 in the second ground layer 52, it is possible to smoothly flow a return current from the first ground layer 51 to the second ground layer 52. This makes it possible to effectively prevent crosstalk occurring between signal lines from worsening.

[0081] The vias 60 also include a second via 62 (horizontal via) located on the second ground layer 52 to the side of the first signal terminal 31 .

[0082] With this configuration, the first via 61 is provided in a location close to the first signal terminal 31 (first signal line 21), which not only ensures a return current path from the first ground layer 51 to the second ground layer 52, but also effectively suppresses crosstalk between the first signal lines 21 in the transparent conductive film 2.

[0083] Here, the crosstalk of the antenna module 1 according to the present embodiment and the antenna module 1X of the comparative example was measured, and the measurement results will be described using Figures 6A and 6B. Figure 6A shows near-end crosstalk (NEXT), and Figure 6B shows far-end crosstalk (FEXT). In Figures 6A and 6B, the dashed lines show the measurement results of the antenna module 1X of the comparative example ("Comparative Example" in the figures), and the solid lines show the measurement results of the antenna module 1 according to the present embodiment ("Example" in the figures).

[0084] As shown in Figures 6A and 6B, it can be seen that the antenna module 1 of this embodiment has lower isolation, which indicates crosstalk, than the antenna module 1X of the comparative example, in both near-end crosstalk and far-end crosstalk, and in all frequency bands.

[0085] Furthermore, in the antenna module 1 according to the first embodiment, only the third ground layer 53 is provided as a ground layer on the flexible wiring board 3 (i.e., there is only one ground layer), but this is not limited to this. For example, as in the antenna module 1A shown in FIGS. 7, 8A, and 8B, the flexible wiring board 3A may be provided with multiple ground layers. FIG. 7 is an enlarged view of a joint between the transparent conductive film 2 and the flexible wiring board 3A in the antenna module 1A according to a modification of the first embodiment. In FIG. 7, (a) shows an end of the transparent conductive film 2, and (b) shows an end of the flexible wiring board 3A. FIG. 8A is a cross-sectional view taken along line A-A in FIG. 7, and FIG. 8B is a cross-sectional view taken along line B-B in FIG. 7. Note that FIG. 7 corresponds to the enlarged view of FIG. 2.

[0086] 7, 8A, and 8B, the antenna module 1A of this modification differs from the antenna module 1 according to the first embodiment in that the flexible wiring board 3A has a fourth ground layer 54. The fourth ground layer 54 is provided on the fourth surface 42b of the second substrate 42. As an example, the fourth ground layer 54 is formed over the entire fourth surface 42b of the second substrate 42, but this is not limiting. The fourth ground layer 54 is also connected to the third ground layer 53 through a via 70 provided in the second substrate 42.

[0087] In this way, by providing the fourth ground layer 54 on the flexible wiring board 3A, not only can the effects of the antenna module 1 in the above-mentioned embodiment 1 be obtained, but crosstalk between the second signal lines 22 on the flexible wiring board 3A can also be effectively suppressed.

[0088] (Embodiment 2) Next, an antenna module 1B according to embodiment 2 will be described with reference to FIGS. 9, 10A, and 10B. FIG. 9 is an enlarged view of a joint between a transparent conductive film 2B and a flexible wiring board 3B in the antenna module 1B according to embodiment 2. In FIG. 9, (a) shows an end of the transparent conductive film 2B (the peripheral portion of the second ground layer 52B), (b) shows an end of the flexible wiring board 3B (the peripheral portion of the third ground layer 53B), and (c) shows an end of the flexible wiring board 3B (the peripheral portion of the fifth ground layer 55). Also, FIG. 10A is a cross-sectional view taken along line A-A in FIG. 9, and FIG. 10B is a cross-sectional view taken along line B-B in FIG. 9. Note that FIG. 9 corresponds to the enlarged view of FIG. 2.

[0089] The antenna module 1B according to the present embodiment differs from the antenna module 1 according to the above-described embodiment 1 in that the shapes in plan view of the second ground layer 52B of the transparent conductive film 2B and the third ground layer 53B of the flexible wiring board 3B are different. Specifically, in the above-described embodiment 1, the shapes in plan view of the second ground layer 52 of the transparent conductive film 2 and the third ground layer 53 of the flexible wiring board 3 are rectangular, but in the present embodiment, the shapes in plan view of the second ground layer 52B of the transparent conductive film 2B and the third ground layer 53B of the flexible wiring board 3B are comb-shaped, as shown in Fig. 9 .

[0090] As shown in (a) of Figure 9, in the transparent conductive film 2B of this embodiment, the second ground layer 52B has a base ground portion 52a and a side ground portion 52b located on the side of the first signal terminal 31.

[0091] The base ground portion 52a is an end ground portion located at an end of the first substrate 41. The base ground portion 52a extends in the arrangement direction of the multiple first signal terminals 31. The base ground portion 52a has a portion located between the end of the first signal terminal 31 and the edge 41c of the first substrate 41, and extends along the edge 41c of the first substrate 41. In the present embodiment, the side edge of the base ground portion 52a coincides with the edge 41c of the first substrate 41, but this is not limited thereto. Specifically, the side edge of the base ground portion 52a may be located at a position set back from the edge 41c of the first substrate 41.

[0092] Furthermore, the side ground portion 52b is provided so as to protrude from the base ground portion 52a in a plan view. In other words, the side ground portion 52b is a protrusion. The side ground portion 52b extends in a direction away from the edge 41c of the first substrate 41. In this embodiment, the side ground portion 52b is arranged in a line along the direction in which the first signal terminals 31 are arranged. The base ground portion 52a connects the side ground portions 52b together. The side ground portions 52b and the first signal terminals 31 are arranged alternately one by one.

[0093] In this embodiment, the first via 61, which is an end via of the plurality of vias 60, is connected to the base ground portion 52a of the second ground layer 52B. The second via 62, which is a horizontal via of the plurality of vias 60, is connected to the side ground portion 52b of the second ground layer 52B. The plurality of second vias 62 are arranged in a row along the longitudinal direction of the first signal terminal 31.

[0094] As shown in FIG. 9B, in the flexible wiring board 3B of this embodiment, the third ground layer 53B has a base ground portion 53a and a side ground portion 53b located on the side of the second signal terminal 32.

[0095] The base ground portion 53a of the third ground layer 53B is located inside the second signal terminal 32. In other words, the second signal terminal 32 is located between the base ground portion 53a and the edge 42c of the second substrate 42B. The base ground portion 53a extends in the arrangement direction of the multiple second signal terminals 32.

[0096] Additionally, the side ground portions 53b of the third ground layer 53B are provided so as to protrude from the base ground portion 53a in a plan view. The side ground portions 53b extend in a direction approaching the edge 42c of the second substrate 42B. In this embodiment, the side ground portions 53b are arranged in the same direction as the second signal terminals 32. The base ground portion 53a connects the side ground portions 53b together. The side ground portions 53b and the second signal terminals 32 are arranged alternately.

[0097] In a plan view, at least a portion of the base ground portion 53a of the third ground layer 53B overlaps with the base ground portion 52a of the second ground layer 52B. Furthermore, at least a portion of the side ground portion 53b of the third ground layer 53B overlaps with the side ground portion 52b of the second ground layer 52B. In this embodiment, the shape of the base ground portion 53a of the third ground layer 53B in a plan view is the same as the shape of the base ground portion 52a of the second ground layer 52B in a plan view, and the outline of the base ground portion 53a of the third ground layer 53B coincides with the outline of the base ground portion 52a of the second ground layer 52B. Furthermore, the shape of the lateral ground portion 53b of the third ground layer 53B in a plan view is the same as the shape of the lateral ground portion 52b of the second ground layer 52B in a plan view, and the outline of the lateral ground portion 53b of the third ground layer 53B in a plan view is the same as the outline of the lateral ground portion 52b of the second ground layer 52B. Specifically, the shape of the third ground layer 53B in a plan view is the same as the shape of the second ground layer 52B in a plan view.

[0098] The antenna module 1B of this embodiment also differs from the antenna module 1 of the first embodiment in the configuration of the second base material 42B of the flexible wiring board 3B and the position of the second signal line 22.

[0099] Specifically, as shown in FIGS. 10A and 10B , the second substrate 42B includes a first substrate layer 421 and a second substrate layer 422 laminated on the first substrate layer 421. The surface of the first substrate layer 421 opposite the second substrate layer 422 (the bottom surface in FIGS. 10A and 10B ) is the third surface 42a of the second substrate 42B. The surface of the second substrate layer 422 opposite the first substrate layer 421 (the top surface in FIGS. 10A and 10B ) is the fourth surface 42b of the second substrate 42B. The first substrate layer 421 and the second substrate layer 422 are insulating layers made of an insulating resin material. The first substrate layer 421 and the second substrate layer 422 may each be made of the same material as the second substrate 42 of the flexible wiring board 3 of the antenna module 1 according to the above-described embodiment.

[0100] 10B , the second signal line 22 is provided between the first base material layer 421 and the second base material layer 422 of the second base material 42B. That is, the second signal line 22 and the second signal terminal 32 are formed on different wiring layers. Specifically, the first base material layer 421 is present between the second signal line 22 and the second signal terminal 32. In addition, in a plan view, an end of the second signal line 22 overlaps with the second signal terminal 32, and the second signal line 22 and the second signal terminal 32 are electrically connected via a via 71 provided in the first base material layer 421.

[0101] The flexible wiring board 3B of the antenna module 1B of this embodiment also differs from the antenna module 1 of the first embodiment in that it has a fourth ground layer 54 and a fifth ground layer 55 .

[0102] The fourth ground layer 54 is provided on the fourth surface 42b of the second substrate 42B, similarly to the flexible wiring board 3A according to the modified example of the above-described embodiment 1. In the present embodiment, the fourth ground layer 54 is also formed on the entire fourth surface 42b of the second substrate 42B, but this is not limiting.

[0103] 10A , the fourth ground layer 54 is electrically connected to the third ground layer 53B via a fifth ground layer 55 provided between the first base layer 421 and the second base layer 422. Specifically, the third ground layer 53B and the fifth ground layer 55 are electrically connected by a via 72 provided in the first base layer 421. The fifth ground layer 55 and the fourth ground layer 54 are electrically connected by a via 73 provided in the second base layer 422.

[0104] 9C, the fifth ground layer 55 has a comb-like shape in a plan view. The fifth ground layer 55 has a base ground portion 55a and a side ground portion 55b located on either side of the second signal line 22.

[0105] The base ground portion 55a of the fifth ground layer 55 is an end ground portion located at the end of the second substrate 42B. The base ground portion 55a extends in the arrangement direction of the multiple second signal lines 22. The base ground portion 55a has a portion located between the end of the second signal line 22 and the edge 42c of the second substrate 42B, and extends along the edge 42c of the second substrate 42B. In the present embodiment, the side of the base ground portion 55a coincides with the edge 42c of the second substrate 42B, but this is not limited thereto. Specifically, the side of the base ground portion 55a may be located at a position set back from the edge 42c of the second substrate 42B.

[0106] Furthermore, the side ground portion 55b of the fifth ground layer 55 is provided so as to protrude from the base ground portion 55a in a plan view. In other words, the side ground portion 55b is a protrusion. The side ground portion 55b extends in a direction away from the edge 42c of the second substrate 42B. In this embodiment, a plurality of side ground portions 55b are provided along the arrangement direction of the plurality of second signal lines 22. The base ground portion 55a connects the plurality of side ground portions 55b. The plurality of side ground portions 55b and the plurality of second signal lines 22 are provided alternately one by one.

[0107] In addition, in a plan view, at least a portion of the lateral ground portion 55b of the fifth ground layer 55 overlaps with the lateral ground portion 53b of the third ground layer 53B. In the present embodiment, the planar shape of the lateral ground portion 55b of the fifth ground layer 55 is the same as the planar shape of the lateral ground portion 53b of the third ground layer 53B, but this is not limited to this.

[0108] In the antenna module 1B configured in this manner, similar to the antenna module 1 according to the first embodiment, the first ground layer 51 and the second ground layer 52B in the transparent conductive film 2B are electrically connected via a via 60 provided in the first substrate 41.

[0109] Therefore, in the antenna module 1B according to this embodiment, the return current generated in the first ground layer 51 also flows to the second ground layer 52B through the via 60. This makes it possible to suppress crosstalk without increasing the number of components.

[0110] In the antenna module 1B of this embodiment, the second ground layer 52B has a base ground portion 52a and a side ground portion 52b, and the third ground layer 53B has a base ground portion 53a and a side ground portion 53b. At least a portion of the base ground portion 53a of the third ground layer 53B overlaps with the base ground portion 52a of the second ground layer 52B, and at least a portion of the side ground portion 53b of the third ground layer 53B overlaps with the side ground portion 52b of the second ground layer 52B.

[0111] With this configuration, the impedance can be controlled by adjusting the shape of at least one of the second ground layer 52 B and the third ground layer 53 B. Specifically, the impedance can be controlled by adjusting the amount of punching of the metal film when punching a metal film (copper foil) to form the second ground layer 52 B and the third ground layer 53 B in a predetermined pattern.

[0112] (Other Modifications) The transparent conductive film and antenna module according to the present disclosure have been described above based on the embodiments, but the present disclosure is not limited to the above-described embodiments.

[0113] For example, in the above embodiment, the conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 are embedded in the grooves of resin layer 412 of first base material 41, but this is not limiting. Specifically, the conductive wires, first signal line 21, and first signal terminal 31 that constitute antenna 10 may be formed on the flat upper surface of resin layer 412 without forming grooves in resin layer 412.

[0114] Furthermore, in the transparent conductive film 2 of the above embodiment, the antenna 10, the first signal terminal 31, and the second ground layer 52 are provided on the first surface 41a of the first substrate 41, but this is not limiting. The antenna 10, the first signal terminal 31, and the second ground layer 52 may be provided inside the first substrate 41, rather than on the exposed surface of the first substrate 41. Similarly, in the transparent conductive film 2, the first ground layer 51 is provided on the second surface 41b of the first substrate 41, but this is not limiting. The first ground layer 51 may be provided inside the first substrate 41, rather than on the exposed surface of the first substrate 41.

[0115] In the flexible wiring board 3 according to the above embodiment, the third ground layer 53 and the second signal terminal 32 are provided on the third surface 42 a of the second base material 42, but this is not limiting. The third ground layer 53 and the second signal terminal 32 may be provided inside the second base material 42, rather than on the exposed surface of the second base material 42.

[0116] In the above embodiment, the antenna 10 is a mesh antenna, but this is not limiting, and the antenna 10 may be formed in a pattern other than a mesh.

[0117] In addition, the present disclosure also includes embodiments obtained by applying various modifications to the above-described embodiments that would occur to a person skilled in the art, and embodiments realized by arbitrarily combining the components and functions of the embodiments within the scope of the present disclosure. Furthermore, the present disclosure also includes any combination of two or more claims from among the multiple claims set forth in the claims at the time of filing, within the scope of technical compatibility. For example, when a dependent claim set forth in the claims at the time of filing is made into a multiple claim or multiple multiple claims that cite all of the superordinate claims within the scope of technical compatibility, the present disclosure also includes any combination of all claims included in that multiple claim or multiple multiple claims.

[0118] The transparent conductive film and antenna module according to the present disclosure can be used in various electrical devices such as mobile terminals.

[0119] REFERENCE SIGNS 1, 1A, 1B Antenna module 2, 2B Transparent conductive film 2a Effective area 2a1 Island area 2b Ineffective area 3, 3A, 3B Flexible wiring board 4a ACF area 5 Connector 10 Antenna 10a Antenna element 21 First signal line 22 Second signal line 31 First signal terminal 31a Connection terminal portion 32 Second signal terminal 41 First substrate 411 Substrate layer 412 Resin layer 41a First surface 41b Second surface 41c Edge 42, 42B Second substrate 421 First substrate layer 422 Second substrate layer 42a Third surface 42b Fourth surface 42c Edge 51 First ground layer 52, 52B Second ground layer 52a Base ground portion 52b Side ground portion 53, 53B Third ground layer 53a: base ground portion 53b: side ground portion 54: fourth ground layer 55: fifth ground layer 55a: base ground portion 55b: side ground portion 60, 70, 71, 72, 73: vias 61: first via 62: second via

Claims

1. An antenna module comprising: a transparent conductive film; and a wiring board connected to the transparent conductive film, wherein the transparent conductive film has: a first substrate having a first surface and a second surface facing the first surface, an antenna provided on the first surface, a first signal terminal provided on the first surface and electrically connected to the antenna, a first ground layer provided on the second surface, and a second ground layer provided on the first surface, wherein the wiring board has: a second substrate, a third ground layer provided on the second substrate, and a second signal terminal provided on the second substrate, wherein at least a portion of the wiring board is disposed to face the transparent conductive film, the first signal terminal and the second signal terminal are electrically connected, the second ground layer and the third ground layer are electrically connected, and the first ground layer and the second ground layer are electrically connected through one or more vias provided in the first substrate.

2. The antenna module described in claim 1, wherein the second base material has a third surface and a fourth surface facing away from the third surface, the third ground layer and the second signal terminal are provided on the third surface, and the wiring board is disposed on the transparent conductive film with the third surface facing the first surface.

3. The antenna module described in claim 1, wherein the second ground layer has a base ground portion located at an end of the first substrate, the base ground portion has a portion located between the first signal terminal and an edge of the first substrate and extends along the edge of the first substrate, and the one or more vias include a first via connected to the base ground portion of the second ground layer.

4. The antenna module described in claim 1, wherein the second ground layer has a side ground portion located on a side of the first signal terminal, the one or more vias have a plurality of second vias connected to the side ground portion, and the plurality of second vias are arranged along the longitudinal direction of the first signal terminal.

5. The antenna module described in claim 2, wherein the second ground layer has a base ground portion located at an end of the first substrate and a side ground portion located on a side of the first signal terminal, the base ground portion of the second ground layer has a portion located between the first signal terminal and an edge of the first substrate and extends along the edge of the first substrate, the one or more vias include a first via connected to the base ground portion of the second ground layer and a plurality of second vias connected to the side ground portion, and the plurality of second vias are arranged along the longitudinal direction of the first signal terminal.

6. The antenna module as described in claim 5, further comprising a plurality of first signal terminals, wherein the second ground layer further has a plurality of side ground portions, wherein each of the plurality of first signal terminals is the first signal terminal, wherein the plurality of first signal terminals are arranged side by side, wherein each of the plurality of side ground portions of the second ground layer is the lateral ground portion of the second ground layer, wherein in a plan view, the plurality of lateral ground portions are arranged to protrude from the base ground portion, and wherein the plurality of first signal terminals and the plurality of lateral ground portions are arranged alternately one by one.

7. The antenna module according to any one of claims 3, 5 and 6, wherein the third ground layer has a base ground portion, and in a planar view, at least a portion of the base ground portion of the third ground layer overlaps with the base ground portion of the second ground layer.

8. The antenna module described in any one of claims 4 to 6, wherein the third ground layer has a side ground portion located on a side of the second signal terminal, and in a planar view, at least a portion of the side ground portion of the third ground layer overlaps with the side ground portion of the second ground layer.

9. The antenna module described in claim 6, wherein the third ground layer has a base ground portion and a side ground portion located on a side of the second signal terminal, and in a planar view, at least a portion of the base ground portion of the third ground layer overlaps with the base ground portion of the second ground layer, and at least a portion of the side ground portion of the third ground layer overlaps with the side ground portion of the second ground layer.

10. The antenna module as described in claim 9, further comprising a plurality of second signal terminals, the third ground layer having a plurality of side ground portions, each of the plurality of second signal terminals being the second signal terminal, each of the plurality of side ground portions being the side ground portion of the third ground layer, the plurality of second signal terminals being arranged side by side, each of the plurality of second signal terminals facing a corresponding one of the plurality of first signal terminals, in a planar view, the plurality of side ground portions of the third ground layer being arranged to protrude from the base ground portion of the third ground layer, and the plurality of second signal terminals and the plurality of side ground portions of the third ground layer being arranged alternately one by one.

11. The antenna module according to claim 2, 5 or 6, wherein the wiring board has a fourth ground layer provided on the fourth surface.

12. The antenna module described in any one of claims 6, 9 and 10, wherein the second substrate has a first substrate layer having the third surface, and a second substrate layer laminated on the first substrate layer and having the fourth surface, a signal line electrically connected to the second signal terminal is provided between the first substrate layer and the second substrate layer, the wiring board has a fourth ground layer provided on the third surface and a fifth ground layer provided between the first substrate layer and the second substrate layer, the second signal terminal is electrically connected to the signal line through a via provided in the first substrate layer, and the third ground layer, the fifth ground layer and the fourth ground layer are electrically connected through vias provided in the first substrate layer and the second substrate layer.

13. An antenna module comprising: a transparent conductive film; and a wiring board connected to the transparent conductive film, wherein the transparent conductive film comprises: a first substrate; an antenna provided on the first substrate; a first signal terminal provided on the first substrate and electrically connected to the antenna; a first ground layer provided on the first substrate; a second ground layer provided on the first substrate and being a layer different from the first ground layer; and a connection line electrically connected to the first ground layer and electrically connecting the first ground layer and the second ground layer; and the wiring board comprises: a second substrate; a third ground layer provided on the second substrate and electrically connected to the second ground layer; and a second signal terminal provided on the second substrate and electrically connected to the first signal terminal, and at least a portion of the second substrate faces the first substrate.

Images