JP2020053311A - Touch sensor, wiring equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch sensor and a wiring device capable of improving the detection accuracy of a touch operation. A touch sensor includes a substrate 30, a sensor electrode 31, and a first ground electrode 32. The substrate 30 has a first layer L1 and a second layer L2. The sensor electrode 31 is formed on the first layer L1. The first ground electrode 32 is formed in the second layer L2 so that at least a part thereof overlaps with the sensor electrode 31 in the thickness direction of the substrate 30, and a parasitic capacitance is formed between the first ground electrode 32 and the sensor electrode 31. At least one of the sensor electrode 31 and the first ground electrode 32 includes a plurality of through holes 320 formed in a region where the sensor electrode 31 and the first ground electrode 32 overlap in the thickness direction of the substrate 30. [Selection diagram] Fig. 4

Description

  The present disclosure relates generally to touch sensors and wiring devices, and more particularly to capacitive touch sensors and wiring devices.

  Conventionally, there is a switch device (wiring device) provided with a touch sensor unit (touch sensor) (for example, see Patent Document 1).

  The switch device of Patent Document 1 includes a switch body and an operation unit.

  The operation unit has a touch sensor unit that detects a human operation (touch operation) and a flat box-shaped housing that houses the touch sensor unit, and the front surface of the housing is used as a detection surface of the touch sensor unit. It is configured.

  The switch device is configured to turn on / off power supply from an external power supply to the load according to a detection result of the touch sensor unit.

JP 2015-187918 A

  In touch sensors, there is a demand for improved detection accuracy of touch operations.

  The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a touch sensor and a wiring device that can improve the detection accuracy of a touch operation.

  A touch sensor according to an aspect of the present disclosure is a capacitance-type touch sensor that detects a touch operation. The touch sensor includes a substrate, a sensor electrode, and a ground electrode. The substrate has a first layer and a second layer. The sensor electrode is formed on the first layer. The ground electrode is formed in the second layer such that at least a part of the ground electrode overlaps the sensor electrode in a thickness direction of the substrate, and a parasitic capacitance is formed between the ground electrode and the sensor electrode. At least one of the sensor electrode and the ground electrode includes a plurality of through holes formed in a region where the sensor electrode and the ground electrode overlap in a thickness direction of the substrate.

  A wiring device according to an aspect of the present disclosure includes the touch sensor, and a control circuit that controls a load based on a detection result of a touch operation performed by the touch sensor.

  According to the present disclosure, there is an effect that detection accuracy of a touch operation can be improved.

FIG. 1 is a block diagram of a wiring device including a touch sensor according to an embodiment of the present disclosure. FIG. 2 is a perspective view of the above wiring device. FIG. 3 is an exploded perspective view of an operation unit included in the wiring device of the above. FIG. 4A is a schematic view of a first layer of a substrate provided in the touch sensor according to the first embodiment. FIG. 4B is a schematic view of a second layer of the substrate. FIG. 4C is a schematic view of a third layer of the substrate. FIG. 4D is a schematic diagram of a fourth layer of the above substrate. FIG. 5 is an enlarged view of a first ground electrode formed on a second layer of the substrate. FIG. 6 is a schematic diagram of the second layer of the substrate in the touch sensor according to the first modification of the embodiment of the present disclosure. FIG. 7 is a schematic diagram of the second layer of the substrate in the touch sensor according to the second modification of the embodiment of the present disclosure. FIG. 8 is a schematic diagram of the second layer of the substrate in the touch sensor according to the third modified example of the embodiment of the present disclosure. FIG. 9A is a schematic diagram of a first layer of a substrate in a touch sensor according to a fourth modification of one embodiment of the present disclosure. FIG. 9B is a schematic view of a second layer of the substrate.

  The embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and the modifications. Various changes can be made according to the design and the like, other than the embodiment and the modified examples, as long as they do not depart from the technical idea of the present disclosure.

  The wiring device 10 according to the present embodiment will be described with reference to FIGS.

  The wiring device 10 of the present embodiment is a switch device that controls power supply from the power supply 40 to the load 41. The wiring device 10 is embedded and disposed in a hole formed in a wall in advance using, for example, a mounting frame 100 (see FIG. 2). The power supply 40 is, for example, a commercial power supply. The load 41 is, for example, an electric device such as a lighting device or a ventilation fan.

  The wiring device 10 includes a switch body 1 and an operation unit 2.

  First, the switch body 1 will be described.

  The switch body 1 is configured to control power supply from the power supply 40 to the load 41. The switch body 1 includes a switch element 11, a control circuit 12, a power supply circuit 13, a first communication unit 14, and a second communication unit 15. The switch body 1 further includes a connector 16, a pair of power terminals 171A and 171B, a pair of load terminals 172A and 172B, and a pair of signal terminals 173A and 173B.

  The switch element 11 is, for example, a bidirectional thyristor. The switch element 11 is electrically connected between the power supply terminal 171B and the load terminal 172B. The switch element 11 is electrically connected to a series circuit of a power supply 40 and a load 41 via a power supply terminal 171B and a load terminal 172B. The control terminal of the switch element 11 is electrically connected to the control circuit 12.

  The switch body 1 has, for example, a microcomputer having a processor and a memory. When the processor executes a program stored in the memory, the microcomputer functions as the control circuit 12. The program executed by the processor is pre-recorded in the memory of the microcomputer here, but may be provided by being recorded on a non-temporary recording medium such as a memory card or provided through an electric communication line such as the Internet. May be done.

  The control circuit 12 controls on / off of the switch element 11. Further, the control circuit 12 controls the first communication unit 14 and the second communication unit 15.

  The power supply circuit 13 is configured to convert an AC voltage output from the power supply 40 into a DC voltage. The power supply circuit 13 is, for example, an AC / DC converter. The power supply circuit 13 outputs a DC voltage converted from the AC voltage to the control circuit 12. The power supply circuit 13 is electrically connected between the power supply terminal 171B and the load terminal 172A. The power supply circuit 13 is electrically connected to the power supply 40 via a power supply terminal 171B and a load terminal 172A. The power supply circuit 13 is electrically connected to the control circuit 12. The power supply circuit 13 converts an AC voltage supplied from the power supply 40 into a DC voltage and outputs the DC voltage to the control circuit 12.

  The control circuit 12 operates with power supplied from the power supply circuit 13. The control circuit 12 supplies power to the operation unit 2 via the connector 16 based on the power supplied from the power supply circuit 13. That is, the power supply circuit 13 supplies power to the operation unit 2 via the control circuit 12.

  The pair of power terminals 171A and 171B are electrically connected to each other. The power supply terminal 171A is used, for example, for sending wiring.

  The first communication unit 14 is a communication interface that enables wired communication. The first communication unit 14 is electrically connected to the pair of signal terminals 173A and 173B. The pair of signal terminals 173A and 173B are connected to a pair of signal lines. The pair of signal terminals 173A and 173B are electrically connected to the pair of signal lines via the pair of signal terminals 173A and 173B. The pair of signal terminals 173A and 173B are electrically connected to the pair of signal terminals 173A and 173B of the switch main body 1 in another wiring device 10 via a pair of signal lines. Further, the first communication unit 14 is electrically connected to the control circuit 12.

  The first communication unit 14 receives, for example, a control signal (first control signal) transmitted from another wiring device 10 using a pair of signal lines via a pair of signal terminals 173A and 173B. The first communication unit 14 outputs the received first control signal to the control circuit 12. In addition, the first communication unit 14 transmits, for example, a control signal (second control signal) from the control circuit 12 to another wiring device 10 via the pair of signal terminals 173A and 173B and the pair of signal lines. .

  The second communication unit 15 is a communication interface that enables wireless communication using radio waves as a medium. In the present embodiment, the second communication unit 15 is configured to be able to perform wireless communication in a low-power wireless (specific low-power wireless) communication method that does not require a license. Regarding the low-power radio, specifications such as a frequency band to be used and an antenna power according to an application or the like are specified in each country. In Japan, a low-power radio using a 400 MHz band or 900 MHz band radio wave is specified. In addition, the second communication unit 15 may be configured to perform wireless communication by a Bluetooth (registered trademark) communication method using radio waves in the 2.4 GHz band.

  The second communication unit 15 is electrically connected to the control circuit 12. The second communication unit 15 receives a control signal (third control signal) transmitted from the control device by wireless communication, for example. The second communication unit 15 outputs the received third control signal to the control circuit 12. In addition, the second communication unit 15 transmits, for example, a control signal (fourth control signal) from the control circuit 12 to the control device by wireless communication.

  The connector 16 is used for electrical and mechanical connection between the switch body 1 and the operation unit 2. The connector 16 is electrically connected to the control circuit 12.

  The switch body 1 further includes a housing 18 (see FIG. 2). The housing 18 is formed in a rectangular box shape by, for example, a synthetic resin. The switch element 11, the control circuit 12, the power supply circuit 13, the first communication unit 14, the second communication unit 15, and the like are housed in a housing 18 while being mounted on a board. The connector 16 is exposed from the front of the housing 18. The pair of power terminals 171A and 171B, the pair of load terminals 172A and 172B, and the pair of signal terminals 173A and 173B are exposed from the rear surface of the housing 18.

  Next, the operation unit 2 will be described.

  The operation unit 2 is configured to receive, for example, an operation (touch operation) input by a person. The operation unit 2 is attached to the front of the switch body 1. The operation unit 2 outputs an operation signal corresponding to the input operation to the switch body 1, for example.

  The operation unit 2 includes a touch sensor 3, a connector 21, and a housing 22 (see FIG. 3).

  The touch sensor 3 is a capacitance-type touch sensor, and detects, for example, a touch operation by a finger or the like of a human body based on a change in parasitic capacitance (capacitance). The touch operation includes a tap operation, a long tap operation, a swipe operation, a slide operation, a flick operation, a pinch operation, and the like.

  The housing 22 is formed in a flat rectangular box shape by the base 23 and the panel 24.

  The base 23 is formed of, for example, a synthetic resin, and has a rectangular bottom wall 230 and a rectangular frame-shaped peripheral wall 231 protruding forward from a peripheral edge of the bottom wall 230. The substrate 30 of the touch sensor 3 is stored in a storage space surrounded by the bottom wall 230 and the peripheral wall 231. The substrate 30 is fixed to the bottom wall 230 of the base 23 with a plurality of screws.

  The panel 24 is formed in a rectangular flat plate shape from a synthetic resin material such as polycarbonate. The panel 24 has translucency and electrical insulation. The panel 24 preferably has a relatively high light diffusion property due to mixing of a light diffusion material, uneven processing, screen printing, or the like. The panel 24 is attached to the front surface 303 of the substrate 30 by a translucent and electrically insulating adhesive sheet 25 so as to cover the opening of the base 23. The front surface 240 of the panel 24 functions as an operation surface on which a user performs a touch operation.

  The board 30 is a multilayer printed board. A plurality of sensor electrodes 31 are formed on the front surface 303 of the substrate 30 (see FIG. 4A). A first ground electrode 32 (ground electrode) is formed on a layer inside the substrate 30 (see FIG. 4B). A parasitic capacitance is formed between each of the plurality of sensor electrodes 31 and the first ground electrode 32. A plurality of electronic components including a resistor, a capacitor, an inductor and the like are mounted on the rear surface 304 of the substrate 30. The plurality of electronic components include a detection unit 34 (see FIGS. 1 and 4D) that detects a touch operation based on a change in parasitic capacitance. The detailed configuration of the substrate 30 will be described later.

  The detection unit 34 has, for example, a microcomputer having a processor and a memory. When the processor executes a program stored in the memory, the microcomputer functions as the detection unit 34. The program executed by the processor is pre-recorded in the memory of the microcomputer here, but may be provided by being recorded on a non-temporary recording medium such as a memory card or provided through an electric communication line such as the Internet. May be done.

  The detection unit 34 monitors the parasitic capacitance of each sensor electrode 31. For example, when the user touches the front surface 240 (operation surface) of the panel 24 with a finger, a new parasitic capacitance is formed between the user's finger and the sensor electrode 31. That is, the parasitic capacitance is formed between the sensor electrode 31 and the first ground electrode 32 and between the sensor electrode 31 and the finger of the user. Therefore, the parasitic capacitance of the sensor electrode 31 increases. The detection unit 34 detects a touch operation by detecting a change (increase) in the parasitic capacitance of the sensor electrode 31.

  The connector 21 (FIGS. 1 and 4D) is provided on the rear surface 304 of the substrate 30. The connector 21 is used for electrical and mechanical connection between the switch body 1 and the operation unit 2. The connector 21 is electrically connected to the detection unit 34. The connector 21 is exposed from the bottom wall 230 of the base 23 in the housing 22. By attaching the operation unit 2 to the switch body 1, the connector 21 and the connector 16 of the switch body 1 are mechanically and electrically connected.

  When detecting the touch operation, the detection unit 34 outputs a signal (operation signal) corresponding to the detected touch operation to the control circuit 12 of the switch body 1 via the connector 21.

  The control circuit 12 controls the switch element 11 according to an operation signal from the operation unit 2. Thereby, the control circuit 12 can control the power supply from the power supply 40 to the load 41. That is, the control circuit 12 controls the load 41 based on the detection result of the touch operation by the touch sensor 3. Further, the control circuit 12 causes the first communication unit 14 to transmit a control signal by wired communication in accordance with an operation signal from the operation unit 2. Further, the control circuit 12 causes the second communication unit 15 to transmit a control signal by wireless communication in accordance with an operation signal from the operation unit 2.

  Next, a detailed configuration of the substrate 30 will be described with reference to FIGS. 4A to 4D.

  The substrate 30 is a four-layer print having a first layer L1 (see FIG. 4A), a second layer L2 (see FIG. 4B), a third layer L3 (see FIG. 4C), and a fourth layer L4 (see FIG. 4D). It is a substrate. The substrate 30 is formed by bonding a plurality of electrically insulating base materials such as a glass epoxy substrate with, for example, a prepreg. In this embodiment, the first layer L1 to the fourth layer L4 are formed by bonding the first outer layer base 3021 and the second outer layer base 3022 to both surfaces of the inner layer base 3020, respectively. I have. The first layer L1, the second layer L2, the third layer L3, and the fourth layer L4 are formed in this order from the front in the thickness direction (front-back direction) of the substrate 30. The first layer L1 is a surface of the first outer layer base material 3021 opposite to the inner layer base material 3020. The second layer L2 is a surface of the first outer layer substrate side 3021 in the inner layer substrate 3020. The third layer L3 is the surface of the second outer layer substrate side 3022 in the inner layer substrate 3020. The fourth layer L4 is the surface of the second outer layer base 3022 opposite to the inner layer base 3020. That is, the first layer L1 is a layer on the front surface 303 (first surface) side of the substrate 30, and the fourth layer L4 is a layer on the rear surface 304 (second surface) side of the substrate 30.

  As shown in FIG. 4A, a plurality of (12 in the present embodiment) sensor electrodes 31 are formed on the first layer L1 of the substrate 30. The sensor electrode 31 is made of a conductive member such as a copper foil, and is formed on the surface of the first outer layer base material 3021 which is the first layer L1 by a photolithography technique or the like.

  In the present embodiment, the twelve sensor electrodes 31 are formed on the first layer L1 of the substrate 30 so as to be arranged two in the left-right direction and six in the up-down direction. Each sensor electrode 31 has a rectangular shape. Each sensor electrode 31 is individually electrically connected to a detection unit 34 provided on the rear surface (fourth layer L4) of the substrate 30. In the touch sensor 3, a plurality of sensor electrodes 31 are formed side by side on a substrate 30. Thus, not only a tap operation (long tap operation) in the touch operation but also a touch operation involving movement such as a swipe operation, a slide operation, a flick operation, and a pinch operation can be detected.

  Note that a plurality of sensor electrodes 31 may be electrically connected. For example, two sensor electrodes 31 arranged in the left-right direction may be electrically connected. In this case, a touch operation involving vertical movement can be detected.

  As shown in FIG. 4B, the first ground electrode 32 is formed on the second layer L2 of the substrate 30. The first ground electrode 32 is formed of a conductive member such as a copper foil, and is formed on the surface of the inner layer base material 3020 which is the second layer L2 by a photolithography technique or the like. The first ground electrode 32 is electrically connected to the detection unit 34.

  The outer shape of the first ground electrode 32 is rectangular. The first ground electrode 32 is formed on the second layer L2 so as to overlap with all of the plurality of sensor electrodes 31 in the thickness direction (front-back direction) of the substrate 30. In other words, each of the plurality of sensor electrodes 31 overlaps the first ground electrode 32 in the thickness direction of the substrate 30. The term "overlapping" as used herein means that each sensor electrode 31 and the first ground electrode 32 overlap when viewed from the thickness direction of the substrate 30, and each sensor electrode 31 and the first ground electrode 32 overlap. 32, a first outer layer base material 3021, a prepreg, and the like are interposed.

  As shown in FIG. 4B, the first ground electrode 32 includes a plurality of through-holes 320 formed in a region A1 overlapping each sensor electrode 31 in the thickness direction of the substrate 30. That is, each sensor electrode 31 partially overlaps with the plurality of through holes 320 in the thickness direction of the substrate 30. As shown in FIGS. 4B and 5, in the present embodiment, the first ground electrode 32 is formed in a mesh shape, and the plurality of through holes 320 are formed as a plurality of meshes. Here, the term “net-like” means that the shape of the conductive member is a net-like shape, and does not mean that the conductive member is knitted. The plurality of through holes 320 are formed regularly in a direction along the surface of the substrate 30. The plurality of through holes 320 have the same opening shape and the same size. The opening shape of each through hole 320 is square, and each side is inclined at 45 degrees or −45 degrees with respect to the vertical direction. That is, the diagonal line of each through-hole 320 extends in the vertical direction or the horizontal direction. However, the shape of the through-hole 320 formed at the periphery of the first ground electrode and at the periphery of the round hole 301 formed so as to penetrate the substrate 30 is different from other through-holes 320.

  The inside of each through-hole 320 is filled with an electrically insulating prepreg for bonding the inner layer base material 3020 and the first outer layer base material 3021. That is, an insulating member having electrical insulation properties is provided inside each through hole 320. In other words, there is no conductive member having electrical conductivity inside each through-hole 320.

  As shown in FIG. 4C, a second ground electrode 33 is formed on the third layer L3 of the substrate 30. The second ground electrode 33 is made of a conductive member such as a copper foil, and is formed on the surface of the inner layer base material 3020, which is the third layer L3, by photolithography or the like. The second ground electrode 33 is formed over the entire surface of the third layer L3 where a conductive member can be formed. The second ground electrode 33 functions as a circuit ground of a sensor circuit formed by a plurality of electronic components mounted on the rear surface 304 of the substrate 30. Further, the second ground electrode 33 is electrically connected to the first ground electrode 32.

  On the fourth layer L4 of the substrate 30, pads for mounting a plurality of electronic components (including the detection unit 34 and the connector 21), wirings for electrically connecting the plurality of electronic components, and the like are formed. The pad and the wiring are made of a conductive member such as a copper foil, and are formed on the surface of the second outer layer base material 3022 as the fourth layer L4 by a photolithography technique or the like. In FIG. 4D, illustration of pads, wirings, and the like is omitted.

  The substrate 30 has a plurality of (five in the present embodiment) round holes 301 formed at the center in the left-right direction and arranged in the up-down direction. The five round holes 301 penetrate the substrate 30. Five light emitting diodes 35 are mounted on the fourth layer L4 of the substrate 30 so as to straddle each of the five round holes 301 (see FIG. 4D). Each light emitting diode 35 is mounted such that light is emitted forward through the round hole 301. The light emitted from the light emitting diode 35 passes through the round hole 301 and is applied to the front of the panel 24 through the translucent adhesive sheet 25 and the panel 24.

(advantage)
In the touch sensor 3 of the present embodiment, the net-like first ground electrode 32 is formed on the second layer L2 of the substrate 30. In the first ground electrode 32, a plurality of through holes 320 are formed in a region A1 overlapping the sensor electrodes 31 formed on the first layer L1 of the substrate 30 in the thickness direction of the substrate 30. Therefore, each sensor electrode 31 partially overlaps with the plurality of through holes 320 of the first ground electrode 32 in the thickness direction of the substrate 30. Accordingly, in the touch sensor 3 of the present embodiment, the parasitic capacitance between each sensor electrode 31 and the first ground electrode 32 is smaller than that in the configuration in which the plurality of through holes 320 are not formed in the first ground electrode 32. Become smaller.

  As described above, when the user touches the front surface 240 (operation surface) of the panel 24 with a finger, a new parasitic capacitance is formed between the user's finger and the sensor electrode 31, so that the parasitic capacitance of the sensor electrode 31 is changed. Increase. The detection unit 34 detects a touch operation by detecting a change (increase) in the parasitic capacitance of the sensor electrode 31 when the touch operation is performed. As the parasitic capacitance between the sensor electrode 31 and the first ground electrode 32 increases, the rate of change in the parasitic capacitance of the sensor electrode 31 before and after the touch operation is performed decreases. Therefore, as the parasitic capacitance between the sensor electrode 31 and the first ground electrode 32 increases, the detection sensitivity of the detection unit 34 for a touch operation decreases.

  The touch sensor 3 of the present embodiment is configured such that the parasitic capacitance between the sensor electrode 31 and the first ground electrode 32 is reduced. Therefore, in the touch sensor 3 of the present embodiment, the detection sensitivity of the touch operation is improved, and the detection accuracy of the touch operation is improved as compared with the configuration in which the plurality of through holes 320 are not formed in the first ground electrode 32. be able to.

  Further, in order to reduce the parasitic capacitance of the sensor electrode 31, a configuration in which the first ground electrode 32 is omitted may be considered. In this case, a parasitic capacitance is formed between the sensor electrode 31 and the second ground electrode 33 formed on the third layer L3 of the substrate 30. The second ground electrode 33 is formed on a third layer L3 opposite to the first layer L1 on which the sensor electrode 31 is formed with respect to the second layer L2. Therefore, in the thickness direction of the substrate 30, the distance between the sensor electrode 31 and the second ground electrode 33 is longer than the distance between the sensor electrode 31 and the first ground electrode 32. Therefore, by omitting the first ground electrode 32, the parasitic capacitance of the sensor electrode 31 is reduced.

  However, in a configuration in which the first ground electrode 32 is omitted, the noise resistance of the sensor electrode 31 decreases. When the noise resistance is low, for example, noise due to a wireless signal or the like is likely to be received, and a touch operation may be erroneously detected. When the noise resistance is low, noise is easily emitted from the sensor electrode 31.

  In the touch sensor 3 of the present embodiment, the first ground electrode 32 is formed on the second layer L2, and the first ground electrode 32 functions as a noise shield for suppressing noise. Therefore, in the touch sensor 3 of the present embodiment, noise resistance is improved as compared with the configuration in which the first ground electrode 32 is omitted. Thereby, erroneous detection of the touch operation is suppressed, and the detection accuracy of the touch operation can be improved.

  As described above, in the touch sensor 3 of the present embodiment, the first ground electrode 32 is formed in a net shape and has a plurality of through holes 320. Thereby, in the touch sensor 3 of the present embodiment, the detection sensitivity of the touch operation and the noise resistance are improved, so that the detection accuracy of the touch operation can be improved. In the first ground electrode 32, in the thickness direction of the substrate 30, the ratio of the area of the plurality of through holes 320 to the region A1 overlapping the sensor electrode 31 is preferably 30% or more and 95% or less.

  In addition, the wiring device 10 of the present embodiment includes a second communication unit 15 (communication unit) that transmits a wireless signal according to a detection result of a touch operation performed by the touch sensor 3. In the touch sensor 3 of the present embodiment, the opening dimension X1 (see FIG. 5) of each through hole 320 in the first ground electrode 32 is set so as to further suppress the influence of noise due to the wireless signal transmitted by the second communication unit 15. Is set. The opening dimension X1 is the maximum value of the size of the opening in the through hole 320. In the present embodiment, the opening shape of the through hole 320 is a square. Therefore, the opening dimension X1 is a diagonal dimension of the opening in the through hole 320 (see FIG. 5).

  The opening dimension X1 of each through hole 320 is set so as to prevent each sensor electrode 31 from receiving a wireless signal transmitted from the second communication unit 15. The opening dimension X1 of each through hole 320 is set based on the frequency of a wireless signal transmitted by the second communication unit 15. Specifically, the opening dimension X1 of each through hole 320 is equal to or less than a quarter of the wavelength of the wireless signal transmitted by the second communication unit 15. The wavelength of the wireless signal is represented by the following equation (1).

λ = c ÷ f × k (1)
In Equation (1), λ is the wavelength of the wireless signal, c is the speed of light [m / s], f is the frequency of the wireless signal [Hz], and k is the wavelength reduction rate of the substrate 30. The wavelength shortening rate k is represented by the following equation (2).

k = 1 / √ε _r (2)
In the equation (2), ε _r is the relative dielectric constant of the substrate 30.

  For example, when the frequency f of the wireless signal is 1 [GHz] and the relative permittivity of the substrate 30 is 4, the wavelength λ is represented by the following equation (3).

λ = 3 × 10 ⁸ ÷ (1 × 10 ⁹ ) × 1 / √4
= 0.15 [m] = 150 [mm] (3)
The opening dimension X1 of each through hole 320 is preferably equal to or less than a quarter of the wavelength λ of the wireless signal, more preferably equal to or less than one eighth of the wavelength λ, and still more preferably equal to or less than one tenth of the wavelength λ. The opening dimension X1 is 18.75 [mm] when it is one eighth of the wavelength λ, and is 15 [mm] when it is one tenth of the wavelength λ.

  Since the opening dimension X1 of each through-hole 320 is formed to the above numerical value, it is possible to prevent each sensor electrode 31 from receiving a wireless signal transmitted from the second communication unit 15 and suppress noise of the sensor electrode 31. be able to. Further, since the first ground electrode 32 is formed between the sensor electrode 31 and the switch body 1 (the second communication unit 15), noise of the sensor electrode 31 can be further suppressed.

(Modification)
Hereinafter, the modified examples will be listed. The modifications described below can be applied in appropriate combinations with the above embodiments.

(Modification 1)
The shape of the first ground electrode 32 is not limited to the shapes shown in FIGS. 4B and 5. As shown in FIG. 6, the first ground electrode 32A may be formed such that each side of each through hole 320A is a square along the vertical direction or the horizontal direction.

  Further, the shape of the first ground electrode 32 is not limited to a mesh shape in which the opening shape of each through hole 320 is a square (quadrangle). As shown in FIG. 7, in the first ground electrode 32B, the opening shape of each through hole 320B may be formed in a circular shape. Further, as shown in FIG. 8, in the first ground electrode 32C, each through hole 320C may be formed in a slit shape. In the example shown in FIG. 8, the opening of the through hole 320C is formed so as to extend along an oblique direction that is inclined with respect to the vertical direction.

(Modification 2)
In the above embodiment, the first ground electrode 32 is configured to include the plurality of through holes 320, but is not limited thereto. As shown in FIG. 9A, each sensor electrode 31D may be configured to include a plurality of through holes 310D.

  In the example shown in FIG. 9A, each sensor electrode 31D is formed in a mesh shape, and a plurality of through holes 320D are formed as a plurality of meshes. Further, in the present modification, as shown in FIG. 9B, the first ground electrode 32D is formed over one surface of a region where a conductive member can be formed in the third layer L3.

  In this modification, a plurality of sensor electrodes 31D formed in a net shape are formed on the first layer L1 of the substrate 30. That is, in each sensor electrode 31D, in the thickness direction of the substrate 30, a plurality of through holes 320D are formed in a region overlapping with the first ground electrode 32D formed in the second layer L2 of the substrate 30. Therefore, the first ground electrode 32D partially overlaps the plurality of through holes 310D of the sensor electrode 31D in the thickness direction of the substrate 30. Thus, in the touch sensor 3 of the present modification, the parasitic capacitance between each sensor electrode 31D and the first ground electrode 32D is smaller than that in the configuration in which the plurality of through holes 310D are not formed in each sensor electrode 31D. Become. Thereby, the detection accuracy of the touch operation can be improved.

  In the present modification, the first ground electrode 32D is formed on one surface of a region where a conductive member can be formed in the third layer L3. Thereby, the noise received by each sensor electrode 31D can be further suppressed.

  Further, the opening area of each through hole 310D in each sensor electrode 31D is preferably smaller than the contact area between the finger and panel 24 when the user performs a touch operation on front surface 240 (operation surface) of panel 24. .

  Further, as shown in FIG. 9B, the first ground electrode 32D is formed over one surface of a region where the conductive member can be formed in the third layer L3, but is not limited thereto. In the third layer L3 of the substrate 30, a first ground electrode 32 (see FIG. 4B) formed in a net shape and having a plurality of through holes 320 may be formed. That is, the touch sensor 3 may have a configuration in which both the sensor electrodes 31D and the first ground electrode 32 are formed in a net shape.

(Other modifications)
In the above-described example, the plurality (12) of the sensor electrodes 31 are formed on the first layer L1 of the substrate 30. However, the number of the plurality of sensor electrodes 31 is not limited to 12, and may be another number. Is also good. Further, the number of the sensor electrodes 31 may be one.

  The outer shape of the sensor electrode 31 is not limited to a rectangular shape, but may be another shape (for example, a circular shape). The plurality of sensor electrodes 31 are not limited to the same outer shape and the same size, but may have different outer shapes and sizes.

  In the example described above, although the first ground electrode 32 has a plurality of through holes 320 formed in a region other than the region A1 (see FIG. 4B) overlapping the plurality of sensor electrodes 31 in the thickness direction of the substrate 30. This is not the case. In the first ground electrode 32, a conductive member may be formed over one surface of a region other than the region A1.

  In the above-described example, the plurality of sensor electrodes 31 are configured to overlap with one first ground electrode 32 in the thickness direction of the substrate 30, but this is not a limitation. A plurality of first ground electrodes may be formed on the second layer L2 of the substrate 30, and the plurality of first ground electrodes may overlap the plurality of sensor electrodes 31 in the thickness direction of the substrate 30.

  In the above-described example, the substrate 30 is a four-layer substrate, but is not limited thereto. The substrate 30 may be a double-sided substrate having only the first layer L1 and the second layer L2, or may be a substrate having three or five or more layers.

(Summary)
The touch sensor (3) according to the first aspect is a capacitive touch sensor that detects a touch operation. The touch sensor (3) includes a substrate (30), sensor electrodes (31, 31D), and ground electrodes (first ground electrodes 32, 32A, 32B, 32C, 32D). The substrate (30) has a first layer (L1) and a second layer (L2). The sensor electrodes (31, 31D) are formed on the first layer (L1). The ground electrodes (32, 32A, 32B, 32C, 32D) are formed on the second layer (L2) so that at least a part thereof overlaps the sensor electrodes (31, 31D) in the thickness direction of the substrate (30). And a sensor electrode (31, 31D), a parasitic capacitance is formed. At least one of the sensor electrode (31, 31D) and the ground electrode (32, 32A, 32B, 32C, 32D) is connected to the sensor electrode (31, 31D) and the ground electrode (32, 32A) in the thickness direction of the substrate (30). , 32B, 32C, 32D) includes a plurality of through holes (320, 320A, 320B, 320C, 310D) formed in an area (A1) where the through holes overlap.

  According to this aspect, the detection sensitivity of the touch operation and the noise resistance are improved, so that the detection accuracy of the touch operation can be improved.

  In the touch sensor (3) according to the second aspect, in the first aspect, the ground electrode (32, 32A, 32B, 32C) of the sensor electrode (31) and the ground electrode (32, 32A, 32B, 32C). Only a plurality of through holes (320, 320A, 320B, 320C) are formed.

  According to this aspect, the detection sensitivity of the touch operation and the noise resistance are improved, so that the detection accuracy of the touch operation can be improved.

  In the touch sensor (3) according to the third aspect, in the second aspect, the substrate (30) further includes a third layer (L3) and a fourth layer (L4). The first layer (L1) is a layer on the first surface (303) side of the substrate (30). The second layer (L2) is an inner layer of the substrate (30) and has first ground electrodes (32, 32A, 32B, 32C) as ground electrodes. The third layer (L3) is an inner layer of the substrate (30) formed on the opposite side of the second layer (L2) from the first layer (L1), and is a second ground electrode (33). Are formed. The fourth layer (L4) is a layer on the second surface (304) side of the substrate (30) formed on the opposite side of the third layer (L3) from the second layer (L2), and An electronic component (detection unit 34) for detecting an operation is arranged.

  According to this aspect, it is possible to suppress transmission of noise of the sensor circuit including the electronic components for detecting the touch operation to the sensor electrode (31).

  In the touch sensor (3) according to the fourth aspect, in the first aspect, among the sensor electrode (31D) and the ground electrode (32D), a plurality of through holes (310) are formed only in the sensor electrode (31D). I have.

  According to this aspect, the detection sensitivity of the touch operation and the noise resistance are improved, so that the detection accuracy of the touch operation can be improved.

  In the touch sensor (3) according to the fifth aspect, in any one of the first to fourth aspects, the plurality of through-holes (320, 320A, 320B, 320C, 310D) extend in a direction along the surface of the substrate (30). Are regularly arranged.

  According to this aspect, in the direction along the surface of the substrate (30), the difference in the detection sensitivity of the touch operation can be reduced.

  In the touch sensor (3) according to the sixth aspect, in any of the first to fifth aspects, at least one of the sensor electrode (31, 31D) and the ground electrode (32, 32A, 32B, 32C, 32D) It is formed in a mesh shape, and a plurality of through holes (320, 320A, 320B, 320C, 310D) are formed as a plurality of meshes.

  According to this aspect, the detection sensitivity of the touch operation and the noise resistance are improved, so that the detection accuracy of the touch operation can be improved.

  In the touch sensor (3) according to the seventh aspect, in any one of the first to sixth aspects, the opening dimension (X1) of each of the plurality of through holes (320) is transmitted according to a detection result of the touch operation. Less than a quarter of the wavelength (λ) of the wireless signal.

  According to this aspect, it is possible to suppress noise received by the sensor electrodes (31, 31D) due to the wireless signal.

  A wiring device (10) according to an eighth aspect controls a load (41) based on the touch sensor (3) according to any one of the first to seventh aspects and a detection result of a touch operation by the touch sensor (3). And a control circuit (12).

  According to this aspect, in the touch sensor (3), the detection sensitivity of the touch operation and the noise resistance are improved, so that the detection accuracy of the touch operation can be improved.

Reference Signs List 10 wiring device 12 control circuit 3 touch sensor 30 substrate 303 front surface (first surface)
304 back surface (second surface)
31, 31D Sensor electrode 310D Through holes 32, 32A, 32B, 32C, 32D First ground electrode (ground electrode)
320, 320A, 320B, 320C Through hole 33 Second ground electrode 34 Detection unit (electronic component)
L1 First layer L2 Second layer L3 Third layer L4 Fourth layer X1 Opening dimension 41 Load

Claims (8)

A capacitance-type touch sensor that detects a touch operation,
A substrate having a first layer and a second layer;
A sensor electrode formed on the first layer;
A ground electrode formed at the second layer so that at least a part thereof overlaps the sensor electrode in a thickness direction of the substrate, and a parasitic capacitance is formed between the sensor electrode and the ground electrode.
At least one of the sensor electrode and the ground electrode includes a plurality of through holes formed in a region where the sensor electrode and the ground electrode overlap in a thickness direction of the substrate.
Touch sensor. Of the sensor electrode and the ground electrode, the plurality of through holes are formed only in the ground electrode,
The touch sensor according to claim 1. The substrate further has a third layer and a fourth layer,
The first layer is a layer on a first surface side of the substrate,
The second layer is a layer inside the substrate, and a first ground electrode as the ground electrode is formed,
The third layer is an inner layer of the substrate formed on a side opposite to the first layer with respect to the second layer, wherein a second ground electrode is formed,
The fourth layer is a layer on the second surface side of the substrate formed on the side opposite to the second layer with respect to the third layer, on which an electronic component for detecting the touch operation is arranged. Done,
The touch sensor according to claim 2. Of the sensor electrode and the ground electrode, the plurality of through holes are formed only in the sensor electrode,
The touch sensor according to claim 1. The plurality of through holes are formed regularly in a direction along the surface of the substrate,
The touch sensor according to claim 1. At least one of the sensor electrode and the ground electrode is formed in a mesh, and the plurality of through holes are formed as a plurality of meshes.
The touch sensor according to claim 1. The opening size of each of the plurality of through holes is equal to or less than a quarter of the wavelength of the wireless signal transmitted in accordance with the detection result of the touch operation.
The touch sensor according to claim 1. A touch sensor according to any one of claims 1 to 7,
A control circuit that controls a load based on a detection result of the touch operation by the touch sensor,
Wiring equipment.

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