Antenna structure and touch sensor provided with same

Abstract

A antenna structure (20) comprises: an antenna electrode (21) that extends along a reference direction (Rd); and a dummy pattern (30) that is disposed around the antenna electrode (21) and may be brought into an electrically non-conductive state with the antenna electrode (21). The antenna electrode (21) is composed of a plurality of conductive wires (14). The dummy pattern (30) has a plurality of dummy segments (31) each comprising the plurality of conductive wires (14). The plurality of dummy segments (31) are arranged with gaps (32) therebetween in the reference direction (Rd). Each gap (32) extends in a direction (intersecting direction) orthogonal to the reference direction (Rd).

Description

Antenna structure and touch sensor including same

[0001] The present invention relates to an antenna structure and a touch sensor including the same.

[0002] 2. Description of the Related Art Conventionally, an antenna structure is known, for example, as disclosed in Patent Document 1.

[0003] Specifically, Patent Document 1 discloses a film antenna including a dielectric layer, an antenna pattern including a mesh structure disposed on the upper surface of the dielectric layer, and a dummy pattern including the same mesh structure as the antenna pattern, the antenna pattern and the dummy pattern being physically and electrically separated from each other by a segmented region.

[0004] Special table 2021-501529 publication

[0005] As described above, the film antenna of Patent Document 1 includes a dummy pattern that includes the same mesh structure as the antenna pattern, thereby increasing the transparency and improving the visibility of the film antenna.

[0006] On the other hand, in the above-mentioned film antenna, the mesh structure of the dummy pattern includes a segmented portion. The segmented portion is formed by partially cutting the mesh line. However, in the above-mentioned film antenna, no specific aspects of the segmented portion, such as its position, size, and range within the entire antenna pattern, are specified. Therefore, depending on the aspect of the segmented portion, the electric field and signal generated from the antenna pattern may interfere with the dummy pattern, weakening the electric field and signal. In other words, in the film antenna of Patent Document 1, the presence of the dummy pattern may degrade the antenna performance of the antenna pattern.

[0007] The present disclosure has been made in view of the above points, and its purpose is to improve visibility in an antenna structure and prevent degradation of antenna performance.

[0008] To achieve the above object, one embodiment of the present disclosure is an antenna structure, which includes an antenna electrode extending along a reference direction and a dummy pattern arranged around the antenna electrode and electrically non-conductive with the antenna electrode. The antenna electrode is composed of a plurality of conductive lines. The dummy pattern has a plurality of dummy divisions, each of which is composed of a plurality of conductive lines. The plurality of dummy divisions are arranged with gaps between them in the reference direction. The gaps between the dummy divisions extend in an intersecting direction intersecting the reference direction.

[0009] According to the present disclosure, in an antenna structure, visibility can be improved and degradation of antenna performance can be prevented.

[0010] FIG. 1 is an overall perspective view of a touch sensor to which an antenna structure according to an embodiment of the present disclosure is applied. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 . FIG. 3 is a perspective view schematically illustrating the touch sensor as viewed from the front surface side. FIG. 4 is a schematic diagram illustrating multiple transmitting electrodes, multiple first wiring portions, and multiple pads as viewed from the back surface side of a substrate. FIG. 5 is a schematic diagram illustrating multiple receiving electrodes, multiple second wiring portions, an antenna electrode, and multiple pads as viewed from the front surface side of a substrate. FIG. 6 is a partial enlarged view of section VI shown in FIG. 5 . FIG. 7 is a partial enlarged view illustrating the configurations of the receiving electrodes, the antenna electrode, and the dummy pattern. FIG. 8 is a partial enlarged view of section VIII shown in FIG. 6 . FIG. 9 is a cross-sectional view schematically illustrating the cross-sectional structure of a conductive line. FIG. 10 is a view equivalent to FIG. 6 , partially enlarged, illustrating the configurations of the antenna electrode and the dummy pattern according to Modification 1. FIG. 11 is a view equivalent to FIG. 8 , partially enlarged, illustrating the configurations of the antenna electrode and the dummy pattern according to Modification 2. Fig. 12 is a diagram corresponding to Fig. 6 showing a partially enlarged view of the configuration of the antenna electrode and the dummy pattern according to Modification 3. Fig. 13 is a diagram corresponding to Fig. 6 showing a partially enlarged view of the configuration of the antenna electrode and the dummy pattern according to Modification 4.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0012] 1 shows an entire touch sensor 1 including an antenna structure 20 (see FIG. 6 ) according to an embodiment of the present disclosure. The touch sensor 1 is a capacitance-type sensor-type input device. The touch sensor 1 is used as an input device for, for example, in-vehicle devices such as car navigation systems, display devices for personal computers, mobile phones, personal digital assistants, portable game machines, copy machines, ticket vending machines, automated teller machines, watches, and the like.

[0013] The touch sensor 1 including the antenna structure 20 is applicable to, for example, devices that perform communication between 3G and 5G in a mobile communication system. The communication frequency of the antenna electrode 21, which will be described later, is a predetermined frequency band, for example, between 0.5 GHz and 30 GHz. Specifically, the communication frequency of the antenna electrode 21 is the 700 MHz band / 800 MHz band / 900 MHz band, 1.5 GHz band, 1.7 GHz band, 2 GHz band, 2.5 GHz band, 3.4 GHz band / 3.5 GHz band, 3.7 GHz band / 4.5 GHz band, 5.0 GHz band, 6.0 GHz band, or 28 GHz band, etc. Details of the antenna structure 20 will be described later.

[0014] In the following description, the side on which an operation surface 2b (see FIGS. 1 and 2) of a cover member 2 (described later) is located will be referred to as the "front side" of the touch sensor 1, and the opposite side will be referred to as the "back side" of the touch sensor 1, and the positional relationship of each element constituting the touch sensor 1 will be defined accordingly. Furthermore, in the embodiment of the present disclosure, for convenience of description, the direction from the left side to the right side of the paper in FIG. 3 will be defined as the "first direction X," while the direction from the bottom side to the top side of the paper in FIG. 3 will be defined as the "second direction Y."

[0015] 3 , the touch sensor 1 is provided with an active area A and a non-active area B. The active area A has a rectangular shape in a plan view. The non-active area B has a rectangular frame shape. The non-active area B is arranged so as to surround the periphery of the active area A in a plan view.

[0016] 1 and 2, the touch sensor 1 includes a light-transmitting cover member 2. The cover member 2 is made of, for example, cover glass or a plastic cover lens. The cover member 2 is formed, for example, in the shape of a rectangular plate in a plan view. The cover member 2 is fixed to a second layer 5 (see FIG. 9) of a substrate 3, which will be described later.

[0017] A roughly frame-shaped decorative portion 2a is formed on the periphery of the back surface of the cover member 2 in a dark color such as black by screen printing or the like. The rectangular area inside this decorative portion 2a is a light-transmitting view area. That is, the user can obtain visual information from a display 100 (see FIG. 2 ) disposed on the back side of the touch sensor 1 through this view area. The surface of the cover member 2 in the view area is configured as an operation surface 2b that comes into contact with the user's fingers or the like during a touch operation.

[0018] 2 and 3, the touch sensor 1 includes one substrate 3. As shown in Fig. 9, the substrate 3 has a first layer 4 and a second layer 5. Each of the first layer 4 and the second layer 5 is formed, for example, in a substantially rectangular shape in a plan view.

[0019] The first layer 4 is made of a transparent resin material, such as polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin polymer (COP), or cycloolefin copolymer (COC).

[0020] The second layer 5 is laminated on the surface of the first layer 4. Although not shown in the drawings, in this embodiment, the second layer 5 is also laminated on the back surface of the first layer 4.

[0021] The second layer 5 is a layer for forming a plurality of grooves 6, which will be described later. The second layer 5 is made of an insulating and transparent resin material. The thickness of the second layer 5 is set to, for example, 1.0 μm or more and 10.0 μm or less to ensure flexibility. The thickness of the second layer 5 is also formed to be greater than the depth of the grooves 6, which will be described later.

[0022] A plurality of grooves 6 are provided on the surface of the second layer 5. Although not shown, a plurality of grooves 6 are also provided on the back surface of the second layer 5. Each groove 6 has a bottom that is recessed in the thickness direction of the substrate 3. The depth of each groove 6 is set to, for example, not less than 0.1 μm and not more than 20 μm.

[0023] 2 , the touch sensor 1 includes an adhesive layer 7. The adhesive layer 7 is laminated between the cover member 2 and the substrate 3. The adhesive layer 7 is an optically transparent adhesive (OCA: Optical Clear Adhesive). The thickness of the adhesive layer 7 is, for example, 25 μm or more and 250 μm or less.

[0024] 1, the touch sensor 1 is provided with a flexible wiring board 8. The flexible wiring board 8 is configured to be flexible and to maintain its electrical characteristics even when deformed. The flexible wiring board 8 is made of a flexible insulating film such as PI (polyimide), PET (polyethylene terephthalate), or PEN (polyethylene naphthalate).

[0025] (Sensor Electrodes) The touch sensor 1 includes a plurality of capacitance-type sensor electrodes. As shown in Figures 3 to 5, the plurality of sensor electrodes are configured by a plurality of transmitting electrodes 11 and a plurality of receiving electrodes 12.

[0026] The plurality of transmitting electrodes 11 and the plurality of receiving electrodes 12 are arranged at positions on the substrate 3 corresponding to the active area A (see FIG. 3 ). The touch sensor 1 is capable of detecting a touch operation by a user's finger (detection target) that touches the operation surface 2 b through the plurality of transmitting electrodes 11 and the plurality of receiving electrodes 12 located in the active area A.

[0027] Each transmitting electrode 11 is connected to a drive circuit of an IC device (not shown) via a flexible wiring board 8. Each transmitting electrode 11 is configured to radiate an electric field to the surroundings by this drive circuit. A predetermined pulse potential for radiating an electric field is applied to the multiple transmitting electrodes 11.

[0028] Each receiving electrode 12 is connected to a detection circuit of an IC device (not shown) via a flexible wiring board 8. Each receiving electrode 12 is configured to detect an electric field radiated from each transmitting electrode 11. A predetermined potential is constantly applied to the multiple receiving electrodes 12 in order to detect the electric fields radiated from the multiple transmitting electrodes 11.

[0029] 3, the transmitting electrodes 11 and the receiving electrodes 12 are arranged to intersect (orthogonally intersect) each other in a plan view. A node is formed in the area where each transmitting electrode 11 and each receiving electrode 12 overlap. The node is configured as an area where electrostatic capacitance can be generated.

[0030] 4, a plurality of transmitting electrodes 11 are provided on the rear surface side of the substrate 3. Each transmitting electrode 11 extends along the long side direction (first direction X) of the substrate 3. The plurality of transmitting electrodes 11 are arranged at intervals from one another in the short side direction (second direction Y) of the substrate 3.

[0031] 5 , the plurality of receiving electrodes 12 are provided on the front surface side of the substrate 3. That is, the plurality of receiving electrodes 12 are arranged on the visible side of the touch sensor 1 (the side on which the operation surface 2 b of the cover member 2 is located) of the substrate 3. The plurality of receiving electrodes 12 are insulated from the plurality of transmitting electrodes 11 via the substrate 3.

[0032] Each receiving electrode 12 extends along the short side direction (second direction Y) of the substrate 3. The multiple receiving electrodes 12 are arranged at intervals from one another in the long side direction (first direction X) of the substrate 3.

[0033] As shown in Fig. 7, the sensor electrodes (receiving electrodes 12) are configured with a predetermined mesh pattern. Although not shown, the transmitting electrodes 11 are also configured with the same mesh pattern as the receiving electrodes 12. In Fig. 7, in order to clearly indicate the area of ​​the receiving electrodes 12, predetermined dot hatching is applied to the area corresponding to the receiving electrodes 12.

[0034] The mesh pattern of the sensor electrode is formed so as to have a plurality of cells 15 arranged side by side, each of which is made up of a plurality of conductive lines 14 (see FIGS. 2, 7, and 9). The mesh pattern (not shown) constituting each transmitting electrode 11 and the mesh pattern (see FIG. 7) constituting each receiving electrode 12 are arranged so as to overlap each other in the thickness direction of the touch sensor 1 (i.e., the thickness direction of the substrate 3).

[0035] Each conductive line 14 is conductive. The plurality of conductive lines 14 extend obliquely relative to each of the first direction X and the second direction Y. The line width of each conductive line 14 is, for example, 1 μm or more and 4 μm or less. The interval between adjacent conductive lines 14, 14 is, for example, 100 μm or more and 500 μm or less.

[0036] Each cell 15 has a quadrangular shape. In this embodiment, the quadrangular shape is a rhombus. Although not shown, the quadrangular shape may be a square or a rectangle.

[0037] (Wiring Section) The touch sensor 1 includes a plurality of wiring sections. The wiring sections are elements for electrically connecting the plurality of transmitting electrodes 11 and the plurality of receiving electrodes 12 to an IC device (not shown) (mainly the drive circuit and detection circuit described above). Each wiring section is made of a conductive line having a cross-sectional structure similar to that of the conductive line 14.

[0038] 3 to 5, the plurality of wiring portions are configured by a plurality of first wiring portions 16 and a plurality of second wiring portions 17. The plurality of first wiring portions 16 and the plurality of second wiring portions 17 are arranged in the inactive area B.

[0039] The first wiring portions 16 and the second wiring portions 17 are arranged at positions overlapping with the decorative portion 2a (see FIGS. 1 and 2) in a plan view seen from the operation surface 2b side. That is, the first wiring portions 16 and the second wiring portions 17 are prevented from being seen from the operation surface 2b side by the decorative portion 2a.

[0040] As shown in Fig. 4, a plurality of first wiring portions 16 are arranged on the back surface of the substrate 3. Each first wiring portion 16 is electrically connected to a corresponding transmitting electrode 11. One end of each first wiring portion 16 is electrically connected to an end of each transmitting electrode 11 located on the left side of the paper surface of Fig. 4.

[0041] 5, a plurality of second wiring portions 17 are disposed on the surface of the substrate 3. Each second wiring portion 17 is electrically connected to a corresponding receiving electrode 12. One end of each second wiring portion 17 is electrically connected to an end of the corresponding receiving electrode 12 that is located on the lower side of the paper surface of FIG.

[0042] 3 to 5, a pad 18 is provided at the other end of each wiring portion for electrical connection to the flexible wiring board 8. Each pad 18 is made of a conductive wire having the same cross-sectional structure as the conductive wire 14.

[0043] 6, an antenna structure 20 according to an embodiment of the present disclosure includes an antenna electrode 21 and a dummy pattern 30. The antenna electrode 21 and the dummy pattern 30 will be described in detail below.

[0044] (Antenna Electrode) The antenna electrode 21 has the function of generating radio waves in space or receiving radio waves from space. As shown in FIGS. 3 and 5 , the antenna electrode 21 in this embodiment is disposed in the active area A. The antenna electrode 21 is provided on the front surface side of the substrate 3. The antenna electrode 21 is disposed between adjacent receiving electrodes 12, 12. In FIGS. 6 to 8 , in order to clearly indicate the area of ​​the antenna electrode 21, predetermined dot hatching is applied to the area corresponding to the antenna electrode 21 (specifically, the first antenna portion 21 a and second antenna portion 21 b described below).

[0045] The antenna electrode 21 in this embodiment is configured as a dipole antenna. As shown in Fig. 6, the antenna electrode 21 has a first antenna portion 21a and a second antenna portion 21b. Each of the first antenna portion 21a and the second antenna portion 21b has a substantially L-shape in a plan view. The first antenna portion 21a and the second antenna portion 21b are disposed at an interval in the second direction Y. Note that, for convenience of illustration, wiring portions connected to the first antenna portion 21a and the second antenna portion 21b are omitted from Figs. 5 to 7.

[0046] 6, the antenna electrode 21 extends along the reference direction Rd. Specifically, each of the first antenna portion 21a and the second antenna portion 21b is configured such that the longer side of the L-shape extends along the reference direction Rd. Here, the "reference direction Rd" is set so as to be along the electric field E generated from the antenna electrode 21 (both the first antenna portion 21a and the second antenna portion 21b).

[0047] The antenna electrode 21 is configured in a mesh pattern, similar to the sensor electrode. That is, the antenna electrode 21 is formed so that a plurality of cells 15, each consisting of a plurality of conductive wires 14, are arranged (see FIG. 8). The plurality of conductive wires 14 that make up the antenna electrode 21 have the same configuration as the conductive wires 14 that make up the sensor electrode.

[0048] (Dummy Pattern) The dummy pattern 30 is disposed in the active area A (see FIG. 6). The dummy pattern 30 is provided on the front surface side of the substrate 3. Note that, for convenience of illustration, the dummy pattern 30 is omitted from FIG. 5. Also, in FIG. 6, in order to clearly indicate the area of ​​the dummy pattern 30, a predetermined dot hatching is applied to the area corresponding to the dummy pattern 30.

[0049] As shown in FIGS. 5 and 7 , the dummy pattern 30 is disposed between adjacent receiving electrodes 12, 12. The dummy pattern 30 is disposed at a distance from the receiving electrode 12. Specifically, the plurality of conductive lines 14 constituting the dummy pattern 30 are disposed at a distance from the plurality of conductive lines 14 constituting the receiving electrode 12. In other words, the grooves 6 located between the receiving electrode 12 and the dummy pattern 30 are not filled with a conductive metal, which will be described later. As a result, the dummy pattern 30 is not electrically connected to the receiving electrode 12. Note that, for convenience of illustration, the plurality of grooves 6 are omitted from FIGS. 5 to 7 .

[0050] 6 and 7 , the dummy pattern 30 is disposed around the antenna electrode 21. The dummy pattern 30 is disposed at a distance from the antenna electrode 21. Specifically, the plurality of conductive lines 14 constituting the dummy pattern 30 are disposed at a distance from the plurality of conductive lines 14 constituting the antenna electrode 21. In other words, the grooves 6 located between the antenna electrode 21 and the dummy pattern 30 are not filled with a conductive metal, which will be described later. As a result, the dummy pattern 30 is not electrically connected to the antenna electrode 21.

[0051] 6 to 8, the dummy pattern 30 has a plurality of dummy divisions 31. Each dummy division 31 is made up of a plurality of conductive lines 14. In addition, in FIGS. 6 to 8, in order to clearly indicate the area of ​​each dummy division 31, predetermined dot hatching is applied to the area corresponding to each dummy division 31.

[0052] 8, the dummy dividing portion 31 is configured so that the length L1 along the reference direction Rd is smaller than the length L2 along the direction perpendicular to the reference direction Rd. In this embodiment, the multiple dummy dividing portions 31 are configured so that the lengths L1 are the same.

[0053] In addition, the dummy division section 31 is configured so that the length L1 along the reference direction Rd is shorter than the total length (length L2) of the second diagonal d2 along the direction perpendicular to the reference direction Rd of multiple cells 15 (described later) that are consecutive in a direction perpendicular to the reference direction Rd.

[0054] Here, if the wavelength of the electric field E generated from the antenna electrode 21 is defined as "λ", the portion of each dummy division 31 corresponding to the reference direction Rd has a length equivalent to, for example, "λ / 32".

[0055] 8 , each dummy dividing portion 31 has a plurality of cells 15. Each cell 15 is formed by a plurality of conductive lines 14. Each cell 15 has a diamond shape. The plurality of cells 15 are continuously arranged in a direction perpendicular to the reference direction Rd (first direction X in the illustrated example).

[0056] In each cell 15 constituting the dummy dividing section 31, the length of the first diagonal line d1 corresponding to the reference direction Rd is defined as L3, while the length of the second diagonal line d2 corresponding to the direction perpendicular to the reference direction Rd is defined as L4. In this embodiment, the length of the first diagonal line d1 (dimension L3) is set to be shorter than the length of the second diagonal line d2 (dimension L4). That is, each cell 15 is configured so that the length along the reference direction Rd (the length corresponding to dimension L3) is shorter than the length along the direction perpendicular to the reference direction Rd (the length corresponding to dimension L4). With this configuration, in each cell 15 constituting the dummy dividing section 31, the electrical resistance of the portion along the reference direction Rd is smaller than the electrical resistance of the portion along the direction perpendicular to the reference direction Rd.

[0057] As a characteristic configuration according to the embodiment of the present disclosure, the multiple dummy dividing portions 31 are arranged with gaps 32 between them in the reference direction Rd. Specifically, the grooves 6 located in the gaps 32 between the dummy dividing portions 31, 31 are not filled with a conductive metal, which will be described later. As a result, the dummy dividing portions 31, 31 are electrically non-conductive to each other.

[0058] In this embodiment, the gap 32 between the dummy dividing portions 31, 31 extends in a direction (first direction X) perpendicular to the reference direction Rd. The gap 32 also extends linearly in the first direction X. The gap 32 is configured as an electric field path P through which the electric field E generated from the antenna electrode 21 passes. Preferably, the gap 32 is set to be equal to or greater than 1 μm and equal to or less than 100 μm.

[0059] In this embodiment, the length of the gap 32 in the second direction Y (dimension L5 shown in FIG. 8) is set to be smaller than the length L1 of the dummy dividing portion 31. Furthermore, the lengths L5 of the multiple gaps 32 are the same as each other.

[0060] (Cross-sectional structure of conductive wire) Next, a description will be given of the cross-sectional structure of the conductive wire 14. The conductive wire 14 includes a conductive metal buried in the groove portion 6. As shown in Fig. 9, the conductive wire 14 is composed of an adhesion layer 41, a seed layer 42, a conductive layer 43, and a blackening layer 44.

[0061] The adhesion layer 41 is an element for ensuring adhesion of the seed layer 42 to the groove portion 6. The adhesion layer 41 has a function of making the conductive lines 14 less visible when a user of the touch sensor 1 views the touch sensor 1 from the operation surface 2b side.

[0062] The adhesion layer 41 is a metal layer made of, for example, a metal nitride or metal oxide containing at least one metal selected from the group consisting of Ti, Ni, Al, V, W, Ta, Si, Cr, Ag, Mo, Cu, and Zn. The adhesion layer 41 may be a single layer or a laminate of multiple layers with different compositions. The adhesion layer 41 is disposed in the form of a thin film on the groove portion 6 by, for example, vapor deposition or sputtering.

[0063] The seed layer 42 has a function of bonding the conductive layer 43 to the adhesion layer 41. Specifically, the seed layer 42 functions as a cathode for depositing a plating solution containing copper (Cu) or the like, which will be described later, on the adhesion layer 41 in this embodiment, for example, during an electroplating process for forming the conductive layer 43. The seed layer 42 is deposited as a thin film on the adhesion layer 41 by, for example, vapor deposition, sputtering, or the like.

[0064] The conductive layer 43 is made of a conductive metal such as copper (Cu). The conductive layer 43 is formed, for example, by electroplating. When the electroplating is performed, the seed layer 42 and the conductive layer 43 are formed integrally. This makes it impossible to distinguish the interface between the seed layer 42 and the conductive layer 43. Note that although copper (Cu) is suitable as the main component of the plating solution used in the electroplating, metals other than copper (for example, silver or gold) may also be included.

[0065] The blackening layer 44 has the function of making the conductive lines 14 less visible when a user of the touch sensor 1 views the touch sensor 1 from the operation surface 2b side. The blackening layer 44 is laminated on the surface of the conductive layer 43. The blackening layer 44 is formed by substituting palladium for copper crystal grains located at the boundaries between copper crystal grains located on the surface of the conductive layer 43 (blackening treatment). The thickness of the blackening layer 44 is, for example, 7 nm or more and 10 nm or less.

[0066] [Effects of the Embodiment] As described above, the antenna structure 20 includes the antenna electrode 21 extending along the reference direction Rd and the dummy pattern 30 disposed around the antenna electrode 21 and electrically disconnected from the antenna electrode 21. The dummy pattern 30 allows the portion where the antenna electrode 21 is provided and the portion where the antenna electrode 21 is not provided to have approximately the same degree of light transmittance. As a result, in the antenna structure 20, compared to a configuration without the dummy pattern 30 (a configuration different from the embodiment of the present disclosure, not shown), when a user of the touch sensor 1 views the touch sensor 1 from the operation surface 2b side, for example, the plurality of conductive lines 14 constituting the antenna electrode 21 and the dummy pattern 30 are less visible from the operation surface 2b side. That is, in the antenna structure 20, the plurality of conductive lines 14 are prevented from becoming "visible." This improves the visibility of the antenna structure 20.

[0067] The multiple dummy divided portions 31 are arranged with gaps 32 between them in the reference direction Rd. The gaps 32 extend in a direction perpendicular to (intersecting) the reference direction Rd. This allows the electric field E generated from the antenna electrode 21 (first antenna portion 21a and second antenna portion 21b) to easily pass through the gaps 32. In other words, the gaps 32 are configured as electric field paths P through which the electric field E passes. This configuration makes it difficult for the electric field E to interfere with the dummy pattern 30 (multiple dummy divided portions 31). In other words, the strength of the electric field E is easily maintained regardless of the presence of the dummy pattern 30. This ensures the antenna performance of the antenna structure 20.

[0068] Therefore, the antenna structure 20 according to the embodiment of the present disclosure can improve visibility and prevent degradation of antenna performance.

[0069] Furthermore, each dummy divided portion 31 is configured so that its length L1 along the reference direction Rd is smaller than its length L2 along a direction intersecting the reference direction Rd (intersecting direction). With this configuration, the electric field E generated from the antenna electrode 21 is less likely to interfere with the multiple dummy divided portions 31, and the electric field E is more likely to pass through the gaps 32 between the dummy divided portions 31. In other words, the strength of the electric field E is more likely to be maintained. As a result, antenna performance is ensured.

[0070] Furthermore, in the dummy division portion 31, the multiple cells 15 are continuously arranged in a direction (intersecting direction) perpendicular to the reference direction Rd. That is, the dummy division portions 31 are continuous in a direction perpendicular to the reference direction Rd. With this configuration, even if gaps 32 are provided between the dummy division portions 31, 31, the integrity of each dummy division portion 31 is maintained in a direction perpendicular to the reference direction Rd (first direction X in the illustrated example). As a result, the original function of the dummy pattern 30 (i.e., the function of improving the visibility of the antenna structure 20) can be ensured.

[0071] Furthermore, each cell 15 is configured so that its length L3 along the reference direction Rd is smaller than its length L4 along a direction perpendicular to the reference direction Rd (the intersecting direction). With this configuration, the electrical resistance of the portion of each cell 15 along the reference direction Rd is relatively small, while the electrical resistance of the portion of each cell 15 along the direction perpendicular to the reference direction Rd is large. Since the electrical resistance of the portion of each cell 15 along the reference direction Rd is relatively small, even if the electric field E generated from the antenna electrode 21 interferes with each dummy division 31, the strength of the electric field E is less likely to attenuate. Therefore, antenna performance can be ensured.

[0072] Furthermore, the gap 32 extends in a direction perpendicular to the reference direction Rd. With this configuration, the electric field E generated from the antenna electrode 21 easily passes through the gap 32 between the dummy divided portions 31, 31. As a result, the antenna performance can be ensured.

[0073] Furthermore, the touch sensor 1 equipped with the antenna structure 20 can have the original function (sensor function) of the touch sensor 1 while also achieving the above-mentioned effects of the antenna structure 20 (i.e., improving visibility and preventing a decline in antenna performance).

[0074] Furthermore, in the touch sensor 1, the antenna electrode 21 and the dummy pattern 30 are disposed between adjacent sensor electrodes (receiving electrodes 12, 12). As a result, when a user of the touch sensor 1 views the touch sensor 1 from the operation surface 2b side, the plurality of conductive lines 14 constituting each of the plurality of sensor electrodes, the antenna electrode 21, and the dummy pattern 30 are difficult to see from the operation surface 2b side. In other words, the plurality of conductive lines 14 are prevented from being "visible" in the touch sensor 1. This improves the visibility of the touch sensor 1.

[0075] [First Modification of the Embodiment] As in the first modification shown in FIG. 10 , the multiple dummy divisions 31 may be arranged with gaps 33 between them in a direction perpendicular to the reference direction Rd. The gaps 33, like the gaps 32, are set to be 1 μm or more and 100 μm or less. In this configuration, compared to the above embodiment, the electric field path P through which the electric field E passes is branched. As a result, it is easier to prevent a deterioration in antenna performance. Note that in the antenna structure 20 and the touch sensor 1, the multiple gaps 33 may be arranged to an extent that does not affect visibility.

[0076] [Second Modification of the Embodiment] As shown in FIG. 11 , the dummy dividing portion 31 may have a slit 34. The slit 34 is disposed at a position corresponding to the intersection of the conductive lines 14. By providing this slit 34, the conductive lines 14 constituting each dummy dividing portion 31 are electrically non-conductive. As a result, in the second modification, the electrical resistance of each dummy dividing portion 31 is relatively reduced in both the portion of each dummy dividing portion 31 along the reference direction Rd and the portion of each dummy dividing portion 31 along a direction intersecting the reference direction Rd, compared to the above-described embodiment and the first modification. As a result, the antenna performance of the antenna structure 20 is more likely to be ensured. Furthermore, by dividing each conductive line 14 into smaller portions by the slit 34, electrical shorts between the conductive lines 14 constituting the dummy dividing portion 31 can be prevented.

[0077] The slits 34 may be arranged to such an extent that they do not affect visibility. In the second modification, at least one slit 34 may be provided.

[0078] 12 , each cell 15 may be configured such that its length along the reference direction Rd is greater than its length along a direction perpendicular to the reference direction Rd. Even in this modification, it is sufficient that the length along the reference direction Rd of each dummy division section 31 is smaller than its length along a direction perpendicular to the reference direction Rd. This can achieve the same effects as the above embodiment.

[0079] [Fourth Modification of the Embodiment] As in the fourth modification shown in FIG. 13 , the gaps 32 between the dummy divisions 31, 31 may extend in a direction intersecting the reference direction Rd (intersecting direction). Specifically, the gaps 32 in this modification extend obliquely with respect to each of the first direction X and the second direction Y. Even in this modification, the same effects as those of the above embodiment can be achieved as long as the multiple dummy divisions 31 are arranged with the gaps 32 between them in the reference direction Rd. Note that in the fourth modification, the dummy divisions 31 located around the first antenna portion 21 a and the second antenna portion 21 b are symmetrical with respect to the center line C shown in FIG. 13 as an axis of symmetry.

[0080] [Other Embodiments] In the above embodiment, the touch sensor 1 including the antenna structure 20 is exemplified, but the present invention is not limited to this embodiment. For example, even an antenna film including only the antenna structure 20 can achieve the above-described effects of the antenna structure 20. Furthermore, the antenna structure 20 may be applied to technical fields other than touch sensors (for example, technical fields related to displays, glass, eyeglasses, and particularly to portions of the antenna sheet that require transparency).

[0081] In the above embodiment, the antenna structure 20 includes one antenna electrode 21, but the present invention is not limited to this. That is, the antenna structure 20 may include a plurality of antenna electrodes 21.

[0082] In the above embodiment, the antenna electrode 21 is provided as a dipole antenna, but the present invention is not limited to this. For example, the antenna electrode 21 may be configured as a monopole antenna or an inverted F-shaped antenna (not shown). Alternatively, the antenna electrode 21 may be configured as a loop antenna for near field communication (NFC) or the like (not shown).

[0083] Furthermore, the antenna electrode 21 may be configured as a patch antenna (not shown). When the antenna electrode 21 is configured as a patch antenna, the reference direction Rd is set so that a plurality of electric fields directed from the radiating element of the antenna electrode 21 to GND are generated at both ends of the radiating element, and the reference direction Rd is set along the combined electric field of the plurality of electric fields.

[0084] In the above embodiment, the antenna electrode 21 is disposed on the front surface side of the substrate 3, but this is not limiting. Although not shown, the antenna electrode 21 may be disposed on the rear surface side of the substrate 3. In such a case, the antenna electrode 21 may be disposed between adjacent transmitting electrodes 11, 11. Furthermore, the dummy pattern 30 shown in the above embodiment may be disposed on the rear surface side of the substrate 3 and around the antenna electrode 21.

[0085] In the above embodiment, the length L1 of each of the dummy division sections 31 is the same as that of the other dummy division sections 31, but this is not limiting. That is, the length L1 of each of the dummy division sections 31 may be different from that of the other dummy division sections 31.

[0086] In the above embodiment, the length L5 of each of the plurality of gaps 32 is the same, but this is not limiting. That is, the plurality of gaps 32 may be configured so that the lengths L5 of each of the plurality of gaps 32 are different from each other.

[0087] In the above embodiment, a rectangular active area A is used, but the present invention is not limited to this. The active area A may have a polygonal shape other than a rectangular shape in a plan view.

[0088] In the above embodiment, a configuration using one substrate 3 has been described, but the present invention is not limited to this. That is, a configuration using two substrates 3 (not shown) may also be used. Although not shown, two substrates 3 may be used in which the second layer 5 is stacked on the front or back surface of the first layer 4.

[0089] In the above embodiment, the substrate 3 has the first layer 4 and the second layer 5, but this is not limiting. For example, the substrate 3 may have only the first layer 4. In such a configuration, it is sufficient that the plurality of grooves 6 are formed on at least one of the front and back surfaces of the first layer 4.

[0090] In the above embodiment, a configuration has been shown in which the plurality of transmitting electrodes 11 and the plurality of first wiring portions 16 are provided on the rear surface side of the substrate 3, while the plurality of receiving electrodes 12, the plurality of second wiring portions 17, the antenna electrode 21, and the dummy pattern 30 are provided on the front surface side of the substrate 3. However, this configuration is not limiting. For example, although not shown, the plurality of transmitting electrodes 11 and the plurality of first wiring portions 16 may be provided on the front surface side of the substrate 3, while the plurality of receiving electrodes 12, the plurality of second wiring portions 17, the antenna electrode 21, and the dummy pattern 30 may be provided on the rear surface side of the substrate 3.

[0091] In the above embodiment, the transmitter electrodes 11 extend along the first direction X, while the receiver electrodes 12 extend along the second direction Y. However, the present invention is not limited to this. For example, although not shown, the transmitter electrodes 11 may extend along the second direction Y, while the receiver electrodes 12 may extend along the first direction X.

[0092] In the above embodiment, the touch sensor 1 is shown in a state in which the cover member 2 and the flexible wiring board 8 are attached to the substrate 3, but this is not limited to this configuration. That is, the concept of the touch sensor 1 according to the present disclosure includes a state before the cover member 2, the flexible wiring board 8, etc. are attached to the substrate 3. Furthermore, the concept of the touch sensor 1 according to the present disclosure also includes a configuration in which the above-mentioned plurality of transmitting electrodes 11, the plurality of receiving electrodes 12, the plurality of first wiring portions 16, the plurality of second wiring portions 17, the plurality of pads 18, the antenna electrode 21, and the dummy patterns 30 are formed on a long base material (e.g., a long hoop-shaped member not shown) in a state before the substrates 3 are individually formed.

[0093] The present disclosure is industrially applicable to an antenna structure and a touch sensor including the same.

[0094] 1: Touch sensor 2: Cover member 3: Substrate 4: First layer 5: Second layer 6: Groove portion 11: Transmitting electrode 12: Receiving electrode 14: Conductive wire 15: Cell 16: First wiring portion 17: Second wiring portion 20: Antenna structure 21: Antenna electrode 21a: First antenna portion 21b: Second antenna portion 30: Dummy pattern 31: Dummy division portion 32, 33: Gap 34: Slit A: Active area B: Inactive area Rd: Reference direction P: Electric field path

Claims

1. An antenna structure comprising: an antenna electrode extending along a reference direction; and a dummy pattern arranged around the antenna electrode and not electrically conductive with the antenna electrode, wherein the antenna electrode is composed of a plurality of conductive lines, the dummy pattern has a plurality of dummy divisions, each of which is composed of a plurality of conductive lines, the plurality of dummy divisions are arranged with gaps between them in the reference direction, and the gaps between the dummy divisions extend in an intersecting direction that intersects the reference direction.

2. An antenna structure according to claim 1, wherein each of the plurality of dummy divisions is configured so that the length along the reference direction is smaller than the length along the intersecting direction.

3. An antenna structure according to claim 1, wherein the dummy division portion has a plurality of cells, each of the plurality of cells being formed by a plurality of conductive lines, and the plurality of cells being arranged consecutively in the intersecting direction.

4. An antenna structure according to claim 3, wherein each of said plurality of cells is configured such that the length along said reference direction is smaller than the length along said intersecting direction.

5. An antenna structure according to claim 1, wherein said gap extends in a direction perpendicular to said reference direction.

6. A touch sensor comprising the antenna structure according to any one of claims 1 to 5.

7. A touch sensor as claimed in claim 6, further comprising a plurality of sensor electrodes arranged at intervals from each other, and the antenna electrode and the dummy pattern are arranged between adjacent sensor electrodes.

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