Touch sensor

Abstract

A touch sensor (1) is provided with an antenna electrode (21) and a plurality of sensor electrodes. The antenna electrode (21) is configured from a plurality of first cells (51). Each first cell (51) includes a plurality of second cells (52). A reception electrode (12) is configured from a plurality of third cells (53). Each third cell (53) includes a plurality of fourth cells (54). The fourth cells (54) are surrounded by conductive wires (14), which surround the third cells (53), and a plurality of dummy conductive wires (55), which are electrically non-conductive with the conductive wires (14) surrounding the third cells (53). The fourth cells (54) have the same aperture ratio as the second cells (52).

Description

Touch Sensor

[0001] The present invention relates to a touch sensor.

[0002] Conventionally, a touch sensor including an electric field antenna such as a monopole antenna or a dipole antenna is known, for example, as disclosed in Patent Document 1. Specifically, Patent Document 1 discloses a touch sensor including an antenna and a touch sensor unit.

[0003] In the touch sensor of Patent Document 1, the antenna 16 has a pattern 54 arranged on the surface 20a of the substrate 20. The pattern 54 of the antenna 16 is composed of a plurality of thin metal wires 50. The pattern 54 of the antenna 16 has a plurality of openings 52.

[0004] The touch sensor unit 12 has a sensor unit 18a (a plurality of first conductive layers 30 and a plurality of second conductive layers 40). The plurality of first conductive layers 30 are arranged on the front surface 20a of the substrate 20. The plurality of second conductive layers 40 are arranged on the back surface 20b of the substrate 20. Each of the first conductive layers 30 and the second conductive layers 40 has a mesh pattern 39 formed in a mesh shape by the intersection of a plurality of conductive thin wires 35. The mesh pattern 39 has a plurality of cells 37. Each cell 37 is made up of a plurality of conductive thin wires 35. The conductive thin wires 35 are thin metal wires made of a metal or an alloy.

[0005] Japanese Patent Application Laid-Open No. 2016-219999

[0006] In Patent Document 1, in an electric field antenna such as a dipole antenna, generally, when the electrical resistance of the antenna becomes relatively low, the voltage value at the tip of the antenna (specifically, the end of antenna 16 located opposite the end to which first wiring 32 is connected (see Figure 1 of Patent Document 1)) increases. This improves the antenna function. For this reason, in order to lower the electrical resistance of the antenna, it is desirable to reduce the aperture ratio of each opening in the antenna pattern.

[0007] Furthermore, the presence of metal near the antenna generally leads to degradation of antenna function. Specifically, in the touch sensor of Patent Document 1, the sensor unit composed of multiple conductive thin wires is located near the antenna, which causes the sensor unit to block the radio waves (electric field) generated from the antenna, resulting in reduced antenna efficiency. To prevent such degradation of antenna function, it is desirable to increase the electrical resistance of the sensor unit. Specifically, to increase the electrical resistance of the sensor unit, it is desirable to increase the aperture ratio of each cell constituting the mesh pattern of each touch sensor unit.

[0008] If the aperture ratio of each opening in the antenna were the same as the aperture ratio of each cell in the touch sensor section, it would be difficult for the user of the touch sensor to distinguish between the antenna pattern and the mesh pattern of each touch sensor section. In other words, the so-called "line visibility" of the multiple thin metal wires 50 and the multiple thin conductive wires 35 would be suppressed. As a result, the visibility of the touch sensor would be improved. However, there is a risk that either the sensor function or the antenna function would be degraded.

[0009] On the other hand, if the aperture ratio of each opening in the antenna differs from the aperture ratio of each cell in each touch sensor unit, it becomes easier to achieve both antenna and sensor functions. On the other hand, it becomes easier for the user of the touch sensor to distinguish between the antenna pattern and the mesh pattern of each touch sensor unit, which makes it easier for the multiple thin metal wires 50 and the multiple thin conductive wires 35 to be "visible." In other words, there is a risk that the visibility of the touch sensor will be impaired.

[0010] The present disclosure has been made in view of the above points, and its purpose is to achieve both an antenna function and a sensor function while improving the visibility as a touch sensor.

[0011] To achieve the above object, one embodiment of the present disclosure is a touch sensor, the touch sensor including an antenna electrode and a plurality of sensor electrodes spaced apart from the antenna electrode. The antenna electrode is composed of a plurality of first cells. The first cell includes a plurality of second cells. The first cells are surrounded by a plurality of conductive lines that are electrically connected to each other. The second cells are surrounded by a plurality of conductive lines that are electrically connected to each other. The sensor electrode is composed of a plurality of third cells. The third cells include a plurality of fourth cells. The third cells are surrounded by a plurality of conductive lines that are electrically connected to each other. The fourth cell is surrounded by a conductive line that surrounds the third cell and a plurality of dummy conductive lines that are electrically non-conductive to the conductive line that surrounds the third cell. The fourth cell has the same aperture ratio as the second cell.

[0012] According to the present disclosure, it is possible to achieve both the antenna function and the sensor function, and also to improve the visibility as a touch sensor.

[0013] FIG. 1 is an overall perspective view of a touch sensor according to an embodiment of the present disclosure. 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 side. FIG. 4 is a schematic diagram illustrating multiple transmitting electrodes, multiple first wiring portions, and multiple pads as viewed from the back 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 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, antenna electrodes (first antenna portions), and dummy patterns shown in FIG. 5 . FIG. 8 is a partial enlarged view of section VIII shown in FIG. 7 . FIG. 9 is a partial enlarged view of section IX shown in FIG. 7 . FIG. 10 is a cross-sectional view schematically illustrating the cross-sectional structure of a conductive line. FIG. 11 is a partially enlarged view corresponding to FIG. 9 illustrating a mesh pattern of a receiving electrode according to Modification 1. FIG. 12 is a partially enlarged view corresponding to FIG. 9 illustrating a mesh pattern of a receiving electrode according to Modification 2. FIG. 13 is a diagram equivalent to FIG. 9, showing a partially enlarged mesh pattern of the receiving electrode according to the third modification.

[0014] 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.

[0015] 1 shows an entire touch sensor 1 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 machines, automated teller machines, watches, and the like.

[0016] In the following description, the side on which an operation surface 2b (see FIGS. 1 and 2) of a cover member 2, which will be 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. In addition, in this embodiment, for the sake of 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," and the direction from the bottom side to the top side of the paper in FIG. 3 will be defined as the "second direction Y."

[0017] 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.

[0018] 1 and 2, the touch sensor 1 includes a light-transmitting cover member 2. The cover member 2 is made of, for example, a 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. 10) of a substrate 3, which will be described later.

[0019] 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.

[0020] 2 and 3, the touch sensor 1 includes one substrate 3. As shown in Fig. 10, 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.

[0021] 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).

[0022] 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.

[0023] 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.

[0024] 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 10 μm.

[0025] 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.

[0026] 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).

[0027] (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 of a plurality of transmitting electrodes 11 and a plurality of receiving electrodes 12. The mesh pattern 13 of the receiving electrodes 12 will be described later.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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. Furthermore, each receiving electrode 12 is arranged at intervals from the antenna electrode 21 (see FIG. 7 ).

[0035] (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 up of a conductive line 14, which will be described later.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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 14, which will be described later.

[0041] 6, the touch sensor 1 includes a dummy pattern 30. The dummy pattern 30 is disposed in the active area A (see FIGS. 5 and 6). The dummy pattern 30 is provided on the front surface side of the substrate 3.

[0042] 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 (see FIG. 7). In other words, the grooves 6 located between the receiving electrode 12 and the dummy pattern 30 are not filled with a conductive metal (described later). As a result, the dummy pattern 30 is electrically non-conductive to the receiving electrode 12 (sensor electrode).

[0043] The dummy pattern 30 is arranged around the antenna electrode 21. The dummy pattern 30 is arranged at a distance from the antenna electrode 21. Specifically, the plurality of conductive lines 14 constituting the dummy pattern 30 are arranged at a distance from the plurality of conductive lines 14 constituting the antenna electrode 21 (see FIG. 7). 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.

[0044] The dummy pattern 30 has a plurality of dummy divisions 31. Each dummy division 31 is composed of a plurality of conductive lines 14. Each dummy division 31 is configured so that its length along the reference direction Rd is shorter than its length along a direction intersecting the reference direction Rd. Note that in Figures 6 and 7, for convenience of illustration, predetermined dot hatching is applied to the areas corresponding to each dummy division 31 to clearly indicate the area of ​​each dummy division 31.

[0045] The multiple dummy dividing portions 31 are arranged with gaps 32 between them in the second direction Y. The gaps 32 extend in a direction perpendicular to the reference direction Rd. The gaps 32 are configured as electric field paths P through which the electric field generated from the antenna electrode 21 passes. Preferably, the gaps 32 are set to be equal to or greater than 1 μm and equal to or less than 100 μm.

[0046] The dummy dividing portion 31 has a plurality of cells. Each cell of the dummy dividing portion 31 is formed by a plurality of conductive lines 14. In this embodiment, each cell of the dummy dividing portion 31 has the same size and shape as a second cell 52, which will be described later. The plurality of cells that make up the dummy dividing portion 31 are arranged continuously in a direction (first direction X) perpendicular to the reference direction Rd.

[0047] Each cell of the dummy dividing portion 31 is configured so that the length along the reference direction Rd is smaller than the length along the direction perpendicular to the reference direction Rd. With this configuration, in each cell of the dummy dividing portion 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.

[0048] 5 to 7, the touch sensor 1 includes an antenna electrode 21. For ease of illustration, in Fig. 6 and Fig. 7, predetermined dot hatching is applied to the area corresponding to the antenna electrode 21 (specifically, the first antenna portion 21a and the second antenna portion 21b described later) in order to clearly indicate the area of ​​the antenna electrode 21.

[0049] The touch sensor 1 including the antenna electrode 21 is applicable to devices that perform communication at frequencies between 3 GHz and 5 GHz, for example. The communication frequency of the antenna electrode 21, which will be described later, is a predetermined frequency band of, for example, 0.5 GHz to 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.

[0050] The antenna electrode 21 has the function of generating radio waves in space or receiving radio waves from space. As shown in Figures 3 and 5, the antenna electrode 21 is disposed in the active area A. Also, as shown in Figure 5, 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. The mesh pattern 22 of the antenna electrode 21 will be described later.

[0051] 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.

[0052] 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).

[0053] 8, the antenna electrode 21 is configured with a mesh pattern 22. The mesh pattern 22 is made up of a plurality of conductive lines 14.

[0054] 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.

[0055] The mesh pattern 22 of the antenna electrode 21 is composed of a plurality of first cells 51. Each first cell 51 is composed of a plurality of conductive wires 14 that are electrically connected to one another. Each first cell 51 has a quadrilateral shape. In this embodiment, the quadrilateral shape is a rhombus. Although not shown, the quadrilateral shape may also be a square or a rectangle.

[0056] The first cell 51 includes a plurality of second cells 52. In this embodiment, one first cell 51 includes four second cells 52. The first cell 51 is surrounded by a plurality of conductive lines 14 that are electrically connected to one another. Each second cell 52 is surrounded by a plurality of conductive lines 14 that are electrically connected to one another.

[0057] The second cells 52 are smaller than the first cells 51. The second cells 52 have a shape similar to that of the first cells 51. That is, the second cells 52 have a quadrangular (diamond) shape. The four second cells 52 have the same shape and size as each other.

[0058] The second cell 52 has approximately the same aperture ratio as the first cell 51. Specifically, the aperture ratio of the second cell 52 is, for example, 90.0% or more and 100% or less. Note that the "aperture ratio" is the ratio obtained by subtracting the ratio (shadow ratio) of the area of ​​one cell occupied by the multiple conductive wires 14 from the total area of ​​the cell (100%).

[0059] (Mesh Pattern of Sensor Electrode) As shown in Fig. 9 , the receiving electrode 12 (sensor electrode) is configured with a mesh pattern 13. Although not shown, the transmitting electrode 11 is also configured with the mesh pattern 13 of the receiving electrode 12. Note that in Figs. 7 and 9 , for convenience of illustration, predetermined dot hatching is applied to the area corresponding to the receiving electrode 12 (mesh pattern 13) in order to clearly indicate the area of ​​the receiving electrode 12 (mesh pattern 13).

[0060] The mesh pattern 13 is made up of a plurality of conductive lines 14. The mesh pattern 13 (not shown) constituting the transmitting electrode 11 and the mesh pattern 13 constituting the 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).

[0061] The mesh pattern 13 is made up of a plurality of third cells 53. The third cells 53 are surrounded by a plurality of conductive lines 14 that are electrically connected to one another.

[0062] The third cell 53 has the same size as the first cell 51. The third cell 53 also has the same shape as the first cell 51. That is, the third cell 53 has a quadrangular shape (diamond shape) like the first cell 51. The third cell 53 also has the same aperture ratio as the first cell 51.

[0063] The third cell 53 includes a plurality of (four in the illustrated example) fourth cells 54. The fourth cells 54 are surrounded by the conductive wires 14 surrounding the third cells 53 and a plurality of dummy conductive wires 55 that are electrically non-conductive with the conductive wires 14 surrounding the third cells 53. Specifically, in this embodiment, one fourth cell 54 is surrounded by two conductive wires 14 and two dummy conductive wires 55 in the third cell 53. The dummy conductive wires 55 are electrically non-conductive with the conductive wires 14 that constitute each third cell 53. The cross-sectional structure of the dummy conductive wires 55 is similar to the cross-sectional structure of the conductive wires 14, which will be described later.

[0064] The fourth cell 54 has the same shape as the second cell 52. That is, the fourth cell 54 has a quadrangular (diamond) shape. The fourth cell 54 also has the same size as the second cell 52. The fourth cell 54 also has the same aperture ratio as the second cell 52. The "aperture ratio" of the fourth cell 54 is the ratio obtained by subtracting the ratio (shadow ratio) of the conductive lines 14, 14 and the dummy conductive lines 55, 55 within one fourth cell 54 from the total area (100%) of the fourth cell 54.

[0065] The fourth cell 54 in this embodiment includes a plurality of (four in the illustrated example) first slit portions 56. Each first slit portion 56 is located between the conductive wire 14 and the end of the dummy conductive wire 55 that constitute the third cell 53. The length of each first slit portion 56 (the distance between the middle of the conductive wire 14 and the end of the dummy conductive wire 55) is, for example, not less than 1 μm and not more than 100 μm.

[0066] The fourth cell 54 in this embodiment includes a plurality of (four in the illustrated example) second slit portions 57. Each second slit portion 57 is located in the middle of the dummy conductive line 55. Specifically, the second slit portion 57 in this embodiment is located approximately in the center of one side of the rectangular shape of the fourth cell 54, which is made up of the dummy conductive line 55. The length of the second slit portion 57 is, for example, not less than 1 μm and not more than 100 μm.

[0067] (Cross-sectional structure of conductive wire) Next, a description will be given of the cross-sectional structure of the conductive wire 14. Each conductive wire 14 includes a conductive metal buried in each groove 6. As shown in Fig. 10, each conductive wire 14 is composed of an adhesion layer 41, a seed layer 42, a conductive layer 43, and a blackening layer 44.

[0068] 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.

[0069] 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.

[0070] 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, during, for example, 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 or sputtering.

[0071] 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.

[0072] 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.

[0073] [Effects of the Embodiment] As described above, the antenna electrode 21 is composed of a plurality of first cells 51. Each first cell 51 includes a plurality of second cells 52, each having approximately the same aperture ratio as the first cell 51. The first cells 51 are surrounded by a plurality of conductive wires 14 that are electrically connected to each other. The second cells 52 are surrounded by a plurality of conductive wires 14 that are electrically connected to each other. With this configuration, the antenna electrode 21 (specifically, the mesh pattern 22) is densified by the plurality of conductive wires 14. As a result, the electrical resistance of the antenna electrode 21 is relatively low. That is, in the antenna electrode 21 of this embodiment, the voltage at each tip end of the first and second antenna portions 22a, 21b (ends located on the opposite sides of the first and second antenna portions 22a, 21b facing each other) is increased. This improves antenna function.

[0074] The receiving electrode 12 (sensor electrode) is composed of a plurality of third cells 53. The third cells 53 include a plurality of fourth cells 54. The third cells 53 are surrounded by a plurality of conductive wires 14 that are electrically connected to each other. The fourth cells 54 are surrounded by the conductive wires 14 that surround the third cells 53 and a plurality of dummy conductive wires 55 that are electrically non-conductive to the conductive wires 14 that surround the third cells 53. With this configuration, the receiving electrode 12 (specifically, the mesh pattern 13) is made denser by the plurality of dummy conductive wires 55. As a result, the electrical resistance of the receiving electrode 12 is relatively high. As a result, even when the plurality of conductive wires 14 are located near the antenna electrode 21, the electric field E generated from the antenna electrode 21 is less likely to be obstructed by the plurality of conductive wires 14. In other words, the antenna function is less likely to deteriorate.

[0075] In a characteristic configuration according to the embodiment of the present disclosure, the fourth cell 54 has the same aperture ratio as the second cell 52. This makes it difficult for a user of the touch sensor 1 to distinguish between the antenna electrode 21 and the receiving electrode 12 (sensor electrode). That is, when viewed from the operation surface 2b side of the touch sensor 1, the user of the touch sensor 1 has difficulty distinguishing between the mesh pattern 22 of the antenna electrode 21 and the mesh pattern 13 of the receiving electrode 12. More specifically, it makes it difficult for a user of the touch sensor 1 to distinguish between the plurality of conductive wires 14 in the first cell 51 and the plurality of second cells 52 and the plurality of conductive wires 14 in the third cell 53 and the dummy conductive wires 55 in each fourth cell 54. This suppresses so-called "line visibility" of the plurality of conductive wires 14 and the plurality of dummy conductive wires 55. That is, the visibility of the touch sensor 1 is improved.

[0076] Therefore, the touch sensor 1 according to the embodiment of the present disclosure can perform both the antenna function and the sensor function, and can improve the visibility of the touch sensor 1 .

[0077] As for the above-mentioned "same aperture ratio as the second cell 52," if the aperture ratio of the fourth cell 54 is 90% or more and 100% or less of the aperture ratio of the second cell 52, it becomes difficult to distinguish between the antenna electrode 21 and the receiving electrode 12 (sensor electrode). As a result, as described above, "line visibility" of the plurality of conductive wires 14 and the plurality of dummy conductive wires 55 is suppressed, and the visibility of the touch sensor 1 is improved.

[0078] Furthermore, the third cell 53 has the same aperture ratio as the first cell 51. This makes it difficult to distinguish between the antenna electrode 21 and the receiving electrode 12 (sensor electrode). Specifically, when viewing the touch sensor 1 from the operation surface 2b side, it becomes difficult for a user of the touch sensor 1 to distinguish between the multiple conductive wires 14 in the first cell 51 and the multiple conductive wires 14 and dummy conductive wires 55 in the third cell 53. This improves the visibility of the touch sensor 1.

[0079] As for the above-mentioned "same aperture ratio as the first cell 51," if the aperture ratio of the third cell 53 is 90% or more and 100% or less of the aperture ratio of the first cell 51, it becomes difficult to distinguish between the antenna electrode 21 and the receiving electrode 12 (sensor electrode). As a result, as described above, it becomes difficult to distinguish between the multiple conductive wires 14 in the first cell 51 and the multiple conductive wires 14 and dummy conductive wires 55 in the third cell 53. This improves the visibility of the touch sensor 1.

[0080] The fourth cell 54 also includes a first slit 56. The first slit 56 is located between the conductive wire 14 of the third cell 53 and the end of the dummy conductive wire 55. This configuration makes it possible to electrically disconnect the conductive wire 14 of the third cell 53 from the dummy conductive wire 55. This allows the receiving electrode 12 (mesh pattern 13) to be made denser or thinner. As a result, the electrical resistance of the receiving electrode 12 becomes relatively high, making it less likely for the antenna function to deteriorate.

[0081] The fourth cell 54 also includes a second slit 57. The second slit 57 is located midway through the dummy conductive line 55. The second slit 57 allows the fourth cell 54 to be subdivided. Furthermore, as an effect of subdividing the fourth cell 54, the electric field E generated from the antenna electrode 21 is less likely to interfere with the receiving electrode 12 (sensor electrode). As a result, the antenna efficiency of the antenna electrode 21 is improved.

[0082] Furthermore, the first cell 51 may have the same shape as the third cell 53. That is, by making the shape of the first cell 51 and the shape of the third cell 53 common, uniformity in appearance can be achieved between the two cells. As a result, the visibility of the touch sensor 1 can be further improved.

[0083] The touch sensor 1 according to this embodiment further includes a substrate 3 on which a plurality of sensor electrodes are provided. The plurality of sensor electrodes include a plurality of transmitting electrodes 11 and a plurality of receiving electrodes 12. The plurality of transmitting electrodes 11 are provided on the rear surface of the substrate 3, and the plurality of receiving electrodes 12 are provided on the front surface of the substrate 3. In this manner, the touch sensor 1 including a single substrate 3 can be made thinner and manufacturing costs can be reduced compared to a touch sensor 1 including, for example, two substrates 3 (see other embodiments described below).

[0084] 11 , the fourth cell 54 may include a third slit portion 58. The third slit portion 58 is located at the intersection of the dummy conductive lines 55, 55 extending in different directions. The third slit portion 58 allows the fourth cell 54 to be subdivided.

[0085] Here, the fourth cell 54 of Modification 1 does not include the second slit portion 57 shown in the above embodiment. However, in Modification 1, the fourth cell 54 includes the first slit portion 56 and the third slit portion 58, and therefore, similar to the above embodiment, it is possible to obtain the effect of dividing the fourth cell 54 into smaller portions (the effect of improving the antenna efficiency).

[0086] 12 , the fourth cell 54 may include only the first slit portion 56. Even in this modification 2, it is possible to electrically disconnect the conductive wire 14 of the third cell 53 from the dummy conductive wire 55. This allows the receiving electrode 12 (mesh pattern 13) to be made denser or coarser.

[0087] 13 , the fourth cell 54 may include all of the above-described first slit portion 56, second slit portion 57, and third slit portion 58. In this modification 3, the fourth cell 54 can be further subdivided in comparison with the configurations of the above embodiment and the above-described modifications 1 and 2.

[0088] Other Embodiments In the above embodiment, the touch sensor 1 includes one antenna electrode 21. However, the present invention is not limited to this. That is, the touch sensor 1 may include a plurality of antenna electrodes 21.

[0089] 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 (not shown).

[0090] 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 configuration, 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.

[0091] In the above embodiment, the third cell 53 has the same shape as the first cell 51, but the present invention is not limited to this. For example, the third cell 53 may have a different shape from the first cell 51. In other words, the shape of the third cell 53 may be different from the shape of the first cell 51 as long as the third cell 53 has the same aperture ratio as the first cell 51 within a range that does not impair the visibility of the touch sensor 1.

[0092] In the above embodiment, the fourth cell 54 has the same shape as the second cell 52, but the present invention is not limited to this. For example, the fourth cell 54 may have a different shape from the second cell 52. That is, the shape of the fourth cell 54 may be different from the shape of the second cell 52 as long as the fourth cell 54 has the same aperture ratio as the second cell 52 within a range that does not impair the visibility of the touch sensor 1.

[0093] In the above embodiment, an example in which four second slit portions 57 are provided has been described, but this is not limiting. For example, in another embodiment, the fourth cell 54 may include one second slit portion 57. Alternatively, the fourth cell 54 may include five or more second slit portions 57.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] The present disclosure is industrially applicable to a touch sensor having an antenna electrode.

[0101] 1: Touch sensor 2: Cover member 3: Substrate 11: Transmitting electrode 12: Receiving electrode 14: Conductive wire 16: First wiring portion 17: Second wiring portion 21: Antenna electrode 21a: First antenna portion 21b: Second antenna portion 30: Dummy pattern 31: Dummy divided portion 51: First cell 52: Second cell 53: Third cell 54: Fourth cell 55: Dummy conductive wire 56: First slit portion 57: Second slit portion 58: Third slit portion A: Active area B: Inactive area Rd: Reference direction P: Electric field path

Claims

1. A touch sensor comprising: an antenna electrode; and a plurality of sensor electrodes spaced apart from the antenna electrode, wherein the antenna electrode is composed of a plurality of first cells, the first cells include a plurality of second cells, the first cells are surrounded by a plurality of conductive lines that are electrically conductive to each other, the second cells are surrounded by a plurality of conductive lines that are electrically conductive to each other, the sensor electrode is composed of a plurality of third cells, the third cells include a plurality of fourth cells, the third cells are surrounded by a plurality of conductive lines that are electrically conductive to each other, the fourth cells are surrounded by a conductive line surrounding the third cell and a plurality of dummy conductive lines that are electrically non-conductive to the conductive line surrounding the third cell, and the fourth cells have the same aperture ratio as the second cell.

2. A touch sensor according to claim 1, wherein the third cell has the same aperture ratio as the first cell.

3. A touch sensor as described in claim 1, wherein the fourth cell includes a first slit portion, and the first slit portion is located between the conductive line constituting the third cell and an end of the dummy conductive line.

4. A touch sensor according to claim 3, wherein the fourth cell includes a second slit portion, and the second slit portion is located in a middle portion of the dummy conductive line.

5. A touch sensor as claimed in claim 3 or 4, wherein the fourth cell includes a third slit portion, and the third slit portion is located at an intersection of the dummy conductive lines extending in different directions.

6. The touch sensor according to claim 1, wherein the first cell has a shape similar to that of the third cell.

7. A touch sensor as described in claim 1, further comprising a substrate on which the plurality of sensor electrodes are provided, the plurality of sensor electrodes having a plurality of transmitting electrodes and a plurality of receiving electrodes, the plurality of transmitting electrodes being provided on a rear surface of the substrate, and the plurality of receiving electrodes being provided on a front surface of the substrate.

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