JP2012129171A - Touch switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch switch capable of reducing regions with reduced detection sensitivity in which contact by a finger cannot be detected.SOLUTION: A touch switch comprises: an insulating layer 3; a plurality of sensor electrodes 21 disposed on a first surface side of the insulating layer 3; a plurality of wiring portions 22 that are disposed on the first surface side of the insulating layer 3 and are each connected to each sensor electrode; a plurality of auxiliary electrodes 4 each disposed in positions facing each sensor electrode 21 on a second surface side of the insulating layer 3; and an insulative protection layer 5 covering the plurality of auxiliary electrodes 4. The boundary between the adjacent auxiliary electrodes 4 is disposed in the region between the adjacent sensor electrodes 21.

Description

  The present invention relates to a capacitive touch switch.

  As a main method of the touch switch, a method for detecting a change in light and a method for detecting a change in electrical characteristics are known. As a method for detecting a change in electrical characteristics, a capacitive coupling method is known and disclosed in, for example, Patent Document 1. The touch switch described in Patent Document 1 is formed by arranging a plurality of sensor electrodes on a substrate. Each sensor electrode is connected to a wiring portion, and each wiring portion is connected to a capacitance detection circuit. When a finger is brought into contact with any of the auxiliary electrodes, the detection position is detected by detecting a change due to the capacitance of the human body with this detection circuit. At this time, the contact position is calculated by detecting the current value flowing through the sensor electrode.

JP 2009-146419 A

  Incidentally, in the touch switch, both the sensor electrode and the wiring portion are arranged on the substrate. For this reason, when the number of sensor electrodes increases, the number of wiring portions increases accordingly, and it is necessary to secure a space for arranging the wiring portions on the substrate. However, the space where the wiring portion is arranged is a region where the sensitivity of detecting a finger or a conductive pen is lowered even if it is brought into contact with it, and it is necessary to make it as small as possible for the function as a touch switch. . In order to solve this problem, it is conceivable to make the wiring part thinner. However, as the number of wiring parts increases, this also has a limit.

  The present invention has been made to solve the above problem, and an object of the present invention is to provide a touch switch capable of reducing a detection sensitivity reduction region in which contact with a finger or the like cannot be detected.

  The touch switch according to the present invention includes an insulating layer, a plurality of sensor electrodes disposed on one surface side of the insulating layer, and a plurality of sensor electrodes disposed on one surface side of the insulating layer and connected to the sensor electrodes, respectively. A plurality of auxiliary electrodes arranged at positions facing the sensor electrodes on the other surface side of the insulating layer, and an insulating protective layer covering the plurality of auxiliary electrodes, A boundary between the adjacent auxiliary electrodes is arranged in a region between the adjacent sensor electrodes.

  According to this configuration, the auxiliary electrode is formed at a position facing the sensor electrode via the insulating layer, and the boundary between the adjacent auxiliary electrodes is arranged in a region between the adjacent sensor electrodes. Therefore, even if a gap is formed between the sensor electrodes, or even if the detection sensitivity reduction region becomes large due to the wiring portion being arranged, by arranging the boundary between the auxiliary electrodes in this detection sensitivity reduction region, The detection sensitivity reduction region is covered by the auxiliary electrode. As a result, the detection sensitivity reduction region is reduced, and even when a finger, a conductive pen, or the like contacts the region between the sensor electrodes, it is possible to prevent the detection sensitivity from decreasing. For example, as the number of sensor electrodes increases, the number of wiring portions also increases accordingly, thereby increasing the detection sensitivity reduction region. However, such a wiring portion is also covered with the auxiliary electrode, so that the detection sensitivity reduction region can be reduced. In the present invention, “the boundary between adjacent auxiliary electrodes is arranged in the region between adjacent sensor electrodes”, but the position of the boundary between the auxiliary electrodes is not necessarily strictly the region between the sensor electrodes. Even if the boundary is arranged at a slightly deviated position, the “region between sensor electrodes” includes the vicinity thereof as long as the detection sensitivity is not greatly reduced.

  In the touch switch, it is preferable to lay a plurality of auxiliary electrodes above the reference region where the plurality of sensor electrodes are arranged. Thereby, the gap between the adjacent auxiliary electrodes is reduced, and the detection sensitivity reduction region can be reduced. Note that the reference region is a region where at least the sensor electrode is disposed, and is a region where a finger, a conductive pen, or the like may come into contact. For example, when the touch switch is arranged on the display device, a region corresponding to the entire display screen of the display device or a part of the display screen used for the operation becomes the reference region.

  In the touch switch, a gap between adjacent auxiliary electrodes can be set to 10 μm to 3 mm, desirably 100 μm to 2 mm, and more desirably 0.5 mm to 1.5 mm. As described above, since the auxiliary electrode can be arranged regardless of the wiring of the wiring portion, the gap between the adjacent auxiliary electrodes can be reduced as described above. Although it is possible even outside the above range, if it is 10 μm or less, there is a possibility that stable insulation between adjacent auxiliary electrodes may not be obtained, and if it is 3 mm or more, the detection sensitivity reduction region becomes too wide for the finger, so that it is stable. There is a possibility that it cannot be detected. The gaps between adjacent auxiliary electrodes do not have to be the same length, and can be changed as necessary.

  In the touch switch, the sensor electrode can be formed by arranging metal wires in a mesh shape. The wiring portion can be formed of at least one metal wire. Thus, by forming with a metal wire, a sensor electrode having optical transparency and a low surface resistance value can be obtained.

  In the touch switch, each auxiliary electrode can be formed in various shapes. For example, at least a part of the edge of the auxiliary electrode is formed so as to form irregularities in the surface direction, and each auxiliary electrode of the adjacent auxiliary electrode is formed. The boundary can be formed so that the irregularities mesh with each other at a predetermined interval. If it does in this way, the detection sensitivity of the contact of the finger | toe in the boundary part with an adjacent auxiliary electrode can be improved.

  In the touch switch, the plurality of sensor electrodes can have the same area. In this way, since the electrostatic capacitance between the sensor electrode and the auxiliary electrode becomes constant, the detection sensitivity can be made uniform at any detection point where a finger or the like comes into contact. The plurality of sensor electrodes are not required to have the same area, and a slight difference is recognized as long as the detection sensitivity is almost uniform.

  According to the touch switch of the present invention, it is possible to reduce a detection sensitivity reduction region where contact with a finger cannot be detected.

It is a top view which shows one Embodiment of the touch switch which concerns on this invention. It is the sectional view on the AA line of FIG. It is the top view and sectional drawing which show the manufacturing method of the touch switch shown in FIG. It is the top view and sectional drawing which show the manufacturing method of the touch switch shown in FIG. It is the top view and sectional drawing which show the manufacturing method of the touch switch shown in FIG. It is a figure explaining the sensing mechanism of the conventional touch switch. It is a figure explaining the sensing mechanism of the touch switch shown in FIG. It is a top view which shows the other example of the auxiliary electrode of the touch switch shown in FIG. It is sectional drawing which shows the other example of the structure of the touch switch shown in FIG. It is a top view which shows the other example of the sensor electrode of the touch switch shown in FIG. It is a top view which shows the other example of the sensor electrode of the touch switch shown in FIG. It is sectional drawing which shows the Example and comparative example of a touch switch which concern on this invention.

  Hereinafter, an embodiment of a touch switch according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view of the touch switch, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIGS. 3 to 5 are plan views and cross-sectional views illustrating a manufacturing method of the touch switch shown in FIG. . In FIG. 1, for convenience of explanation, the protective layer described later is omitted.

  The touch switch of this embodiment is a capacitive touch switch disposed on the upper surface of a display device such as a liquid crystal display panel. As shown in FIGS. 1 and 2, this touch switch has a transparent substrate 1 on which a sensor electrode 21, an insulating layer 3, an auxiliary electrode 4, and a protective layer 5 are arranged in this order. Are stacked. A plurality of sensor electrodes 21 are formed on the substrate 1 in a rectangular shape, and are arranged in a reference region R that may be touched with a finger or a conductive pen. As shown in FIG. 3, each sensor electrode 21 is integrally connected with a wiring portion 22 extending linearly. Each wiring portion 22 is wired so as to extend to the end portion of the substrate 1, and the other end portion is connected to a capacitance detection circuit (not shown). The wiring portion 22 preferably has a low resistance in consideration of the distance and width. For example, the surface resistivity is preferably 10Ω / □ or less. In the present embodiment, ten sensor electrodes 21 are arranged on the substrate 1, and two rows of five sensor electrodes 21 arranged in the vertical direction in FIGS. 1 and 3 are arranged. Here, for convenience of explanation, the first to fifth sensor electrodes 21a to 21e are referred to from the top to the bottom of FIGS. And since the sensor electrodes 21a-21e of each row | line are the same, the sensor electrode of the right side of FIG. 3 is demonstrated. For convenience of explanation, the vertical direction in FIGS. 1 and 3 is referred to as a longitudinal direction, and the horizontal direction is referred to as a width direction.

  As shown in FIG. 3, the first sensor electrode 21a is arranged at one end in the longitudinal direction of the substrate 1 (upper side in FIG. 3), and the other end in the longitudinal direction from the right end of the sensor electrode 21a. The wiring portion 22a extends in a straight line up to (lower side in FIG. 3). The second sensor electrode 21b is disposed on the other end side in the longitudinal direction than the first sensor electrode 21a, and the length in the width direction is smaller than that of the first sensor electrode 21a. That is, the sensor electrodes 21a and 21b are arranged so that the left side in the width direction is aligned, but the right side of the second sensor electrode 21b is more in contact with the wiring part 22a of the first sensor electrode 21a. Located on the left side. The wiring portion 22b of the second sensor electrode 21b extends linearly in parallel with the wiring portion 22a of the first sensor electrode 21a from the right end portion of the second sensor electrode 21b to the other end portion side in the longitudinal direction. Similarly, the third to fifth sensor electrodes 21c to 21e are gradually reduced in width so that they do not come into contact with the wiring portions of adjacent sensor electrodes on one end side in the longitudinal direction. The width of the electrode 21e is the smallest. In addition, each of the wiring portions 22a to 22e is formed to be bent in an L shape at the end portion of the substrate 1, thereby increasing the interval between the wiring portions 22a to 22e at the end portion of the substrate 1. Yes.

  An insulating layer 3 is formed on the upper surfaces of the sensor electrodes 21a to 21e formed as described above (see FIG. 4). The insulating layer 3 has a thickness of 10 to 500 μm and is arranged so as to cover all the sensor electrodes 21 and the wiring portions 22. A plurality of auxiliary electrodes 4 are arranged on the insulating layer 3. Ten auxiliary electrodes 4 are arranged in the same manner as the sensor electrodes 21, and two auxiliary electrodes 4 arranged in the vertical direction in FIG. 1 are arranged in two rows. Here, as in the description of the sensor electrodes, the first to fifth auxiliary electrodes 4a to 4e are referred to from the top to the bottom of FIG. 1, and the auxiliary electrodes 4a to 4e in each column are the same. The right auxiliary electrode will be described. For example, in the case of indium tin oxide (ITO), each of the auxiliary electrodes 4a to 4e has a thickness of 10 to 100 nm, and is disposed on the insulating layer 3 at a position corresponding to each of the sensor electrodes 21a to 21e. All the auxiliary electrodes 4a to 4e are formed in a square having the same size, and are arranged at a narrow interval. More specifically, as shown in FIG. 2, a boundary b between adjacent auxiliary electrodes 4 is arranged in a region L between adjacent sensor electrodes 21, and the sensor electrode 21 is formed by the auxiliary electrode 4. A region L between them is filled. That is, the wiring part 22 disposed between the sensor electrodes 21 is covered with the auxiliary electrode 4. The surface resistivity of the auxiliary electrode 4 may be higher than that of the sensor electrode 21, and is preferably 1 kΩ / □ or less, and more preferably 300Ω / □ or less. The auxiliary electrode 4 is electrically independent and is not in conduction with any member. The plurality of auxiliary electrodes 4 arranged as described above are covered with a protective layer 5. The thickness of the protective layer 5 is preferably larger than the insulating layer 3 described above, and can be, for example, 0.5 to 10 mm.

  Further, as shown in FIG. 1, the length s of the gap between the adjacent auxiliary electrodes 4 can be 10 μm to 3 mm, preferably 100 μm to 2 mm, and more preferably 0.5 mm to 1.5 mm. be able to. Although it is possible even outside the above range, if it is 10 μm or less, there is a possibility that stable insulation between adjacent auxiliary electrodes 4 cannot be obtained. In addition, if it is 3 mm or more, the detection sensitivity reduction region is too wide for the finger, so that stable detection may not be possible. Note that the lengths s of the gaps between the adjacent auxiliary electrodes 4 do not have to be the same, and can be changed depending on the position.

  Next, the material of each member mentioned above is demonstrated. First, the substrate 1 will be described. The substrate 1 can be formed of various materials such as a transparent inorganic material, an organic material, or an organic / inorganic hybrid material, and the material is not particularly limited. For example, an organic material is preferable from the viewpoint of light weight and impact resistance, and a plastic film is preferable from the viewpoint of flexibility and roll-to-roll productivity. Examples of the plastic film include polyester terephthalate (PET), polyethylene naphthalate (PEN), acrylic (PMMA), and polycarbonate (PC). However, these materials are not simple substances, but those with an anchor layer such as a silane coupling layer formed to improve adhesion, those with surface treatment such as corona treatment or plasma treatment, and those with improved scratch resistance and chemical resistance. Therefore, a hard coat layer can be used.

The sensor electrode 21, the wiring part 22, and the auxiliary electrode 4 can be formed of various known materials and are not particularly limited, but can be appropriately selected from necessary physical properties such as conductivity and transparency. Examples thereof include metals such as aluminum, silver and copper, and metal oxide materials such as indium tin oxide (ITO), zinc oxide (ZnO), and tin oxide (SnO ₂ ). Further, a metal such as aluminum, gallium, or titanium can be added to these metal oxide materials. In addition, organic materials such as transparent conductive polymers such as PEDOT / PSS are also included, and these may be used alone or in combination. Since the sensor electrode 21 and the wiring part 22 need to have a low surface resistivity as described above, for example, a three-layer structure in which a silver layer is sandwiched between two ITO layers can be formed.

  The insulating layer 3 is not particularly limited as long as it is transparent and has no electrical conductivity. However, it is desirable that the insulating layer 3 has high adhesion to the auxiliary electrode 4 and the sensor electrode 21 disposed on the upper and lower surfaces thereof. General transparent adhesives and pressure-sensitive adhesives such as epoxy-based and acrylic-based materials can be used, and a transparent film of polyester-based resin or the like may be included. The thickness is not particularly limited, but is preferably 200 μm or less for practical use.

  The protective layer 5 can be formed of a known transparent material used for a general touch switch. The protective layer 5 can be formed of, for example, silicon nitride, silicon dioxide, benzocyclobutene (BCB), polyester, or acrylic acid. Moreover, resin films, such as glass and surface-hardened PET, can be laminated.

  Next, a manufacturing method of the touch switch configured as described above will be described with reference to FIGS. First, as shown in FIG. 3, a plurality of sensor electrodes 21 and wiring portions 22 are formed on the substrate 1. There are various formation methods, and examples thereof include a patterning method after forming the material of the sensor electrode 21 and the wiring portion 22 on the entire surface of the substrate 1. Examples of the method for forming this material include vacuum coating, dry coating such as sputtering and CVD, and wet coating such as gravure coating and spray coating. The patterning method is not limited, and examples thereof include photolithography and laser etching. The former removes the film with chemicals, and the latter removes the film by absorbing laser light of a specific wavelength. Desirably, patterning of the sensor electrode 21 and the wiring part 22 is provided with invisible property (the difference between the presence and absence of the electrode is invisible). From this viewpoint, the third harmonic of YAG capable of removing the film with a width of 10 μm or less is used. It is preferable to use the used laser etching. Compared with photolithography, laser etching has advantages such as the absence of chemicals, good environment and fewer man-hours, and the fact that photomasks are not required and patterning is possible from CAD data, making wiring design more convenient. Can be mentioned. In addition, a paste of silver or the like can be formed into a fine line pattern by screen printing or the like.

  Next, as shown in FIG. 4, the insulating layer 3 is formed so as to cover the entire sensor electrode 21 and the wiring portion 22. The insulating layer 3 can be formed by the same method as the sensor electrode 21 described above.

  Subsequently, as shown in FIG. 5, the auxiliary electrode 4 is formed on the insulating layer 3. The auxiliary electrode 4 can be formed by the same method as the sensor electrode 21 described above. The patterning of the sensor electrode 21, the wiring part 22, and the auxiliary electrode 4 needs to be appropriately selected in consideration of the formation order and the material. Finally, the protective layer 5 is formed on the auxiliary electrode 4. The protective layer 5 can be formed by a known method.

The touch switch configured as described above is used as follows. The touch position detection method is the same as that of the conventional electrostatic capacitance type touch switch. By detecting a change in the electrostatic capacitance when an arbitrary position on the surface of the protective layer 5 is touched with a finger or the like, the touch position is detected. A location is identified. Here, the sensing mechanism when the auxiliary electrode 4 is used as described above is as follows. First, a conventional touch switch having no auxiliary electrode as shown in FIG. 6 will be described. Generally, in a touch switch, the capacitance is proportional to the area of a finger touching the protective layer 5 above the sensor electrode 21. In the example shown in FIG. _6A , since all of the touched portion of the finger is above the sensor electrode 21, the capacitance C _x0 increases. On the other hand, as shown in FIG. 6B, when the upper part of the wiring portion 22 between the sensor electrodes 21 is touched with a finger, the area of the finger on each sensor electrode 21 is small. The combined capacitance (C _x01 + C _X02 ) is smaller than the capacitance C _{x0 in} FIG. _6A , and the sensitivity is lowered.

On the other hand, when the auxiliary electrode 4 is provided like the touch switch of this embodiment, it is as follows. First, as shown in FIG. 7A, when the upper side of the sensor electrode 21 is touched with a finger, the combined capacitance C _n between the finger and the sensor electrode 21 is expressed by the following equation. Here, C ₀ is a capacitance between the sensor electrode 21 and the auxiliary electrode 4, and C _x1 is a capacitance between the auxiliary electrode 4 and the finger.

C _n = C _x1 / (1 + C _x1 / C ₀ ) (1)
At this time, when the distance between the sensor electrode 21 and the auxiliary electrode 4 is sufficiently small, C _x1 << C ₀ and Cx ₁ / C _{0 in} the above equation (1) is a value close to 0. a _n ≒ _{C x1.}

On the other hand, as shown in FIG. 7B, when touching between adjacent sensor electrodes 21, the auxiliary electrode 4 is disposed between the sensor electrodes 21, so that the behavior differs from that in FIG. 6B. Show. That is, there is a gap between the auxiliary electrodes 4, but this is very small compared to the gap between the sensor electrodes 21, so that when the region between the sensor electrodes 21 is touched, the auxiliary electrode corresponding to each sensor electrode 21 is provided. The gap between the sensor electrodes 21 can be complemented between the adjacent auxiliary electrodes 4 by the electrodes 4. Accordingly, the total capacitance C _{n at} this time is _expressed by the following equation (2), which is substantially the same as the capacitance C _x1 shown in FIG. C _x11 is a capacitance between one auxiliary electrode and the finger, and C _x12 is a capacitance between the other auxiliary electrode and the finger.

C _{n ≈C x11} + C _{x12 ≈C x1} (2)
According to the present embodiment described above, the auxiliary electrode 4 is formed at a position facing the sensor electrode 21 via the insulating layer 3, and as shown in FIG. A boundary b between adjacent auxiliary electrodes 4 is arranged. Therefore, even if the detection sensitivity reduction region becomes large due to the wiring part 22 being arranged between the sensor electrodes 21, the detection sensitivity is reduced by arranging the boundary b between the auxiliary electrodes 4 in this detection sensitivity reduction region. The area is covered by the auxiliary electrode 4. As a result, the detection sensitivity reduction region is reduced, and the detection sensitivity can be improved even if a finger or a conductive pen contacts the region L between the sensor electrodes 21.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning. For example, in the above embodiment, the sensor electrode 21 and the auxiliary electrode 4 are formed in a rectangular shape, but this shape is not particularly limited, and can be various shapes such as a polygonal shape, a circular shape, and an irregular shape. . In addition, a linear gap is formed between the adjacent auxiliary electrodes 4. An unevenness extending in the surface direction is formed on the edge of the auxiliary electrode 4, and the adjacent auxiliary electrodes 4 are engaged with each other to engage the adjacent auxiliary electrode 4. The boundary of the electrode 4 can be formed. For example, as shown in FIG. 8, a plurality of sharp protrusions can be formed on the edge of the auxiliary electrode 4, and these can be engaged with each other. In this way, the sensitivity of detection is higher than when the gap between the auxiliary electrodes 4 is linear. In other words, if the unevenness is formed on the edge of the auxiliary electrode 4, there is a high possibility of contact with any one of the adjacent auxiliary electrodes 4 when a finger is placed on the boundary portion. Sensitivity can be improved. The unevenness can be not only the sharp shape as described above but also various shapes such as a rectangular shape and a waveform.

  Moreover, in the said embodiment, although the sensor electrode 21, the wiring part 22, and the auxiliary electrode 4 were laminated | stacked directly, what formed these in the film form can also be laminated | stacked. For example, in the example shown in FIG. 9, a material in which a sensor electrode 21 and a wiring part 22 are formed on an insulating transparent film 6 such as PET, and a material in which an auxiliary electrode 4 is formed on a similar insulating transparent film 6 are prepared. And these are laminated | stacked with the board | substrate 1 and the protective layer 5 through the insulating adhesive material 8. FIG. Moreover, the formation method of an electrode and a wiring part is the same as the method mentioned above. In the example shown in FIG. 9, the transparent film 6 and the adhesive material 8 disposed between the sensor electrode 21 and the auxiliary electrode 4 constitute the insulating layer of the present invention. Alternatively, an insulating transparent film is used as an insulating layer, and the sensor electrode 21 and the wiring portion 22 are formed on one surface thereof, and the auxiliary electrode 4 is formed on the other surface, and this is formed between the substrate 1 and the protective layer 5. It can also be placed in between. Thus, when forming the sensor electrode 21 and the wiring part 22 in a film, the board | substrate 1 is not necessarily required.

  Moreover, the touch electrode 21, the wiring part 22, and the auxiliary electrode 4 can also be formed of at least one metal wire. For example, as shown in FIG. 10, the touch electrode 21 and the wiring part 22 can be formed by arranging the metal wires 20 in a mesh shape having a certain area. Moreover, the wiring part 22 can also arrange | position a some metal wire in parallel other than mesh shape. The width of the metal wire 20 can be 5 to 50 μm, for example, and the pitch of the metal wire 20 in the mesh can be 100 to 1000 μm, for example. By forming each electrode and wiring portion with such a metal wire, the electrode can have optical transparency and a surface resistance value can be lowered.

  Moreover, in the said embodiment, although the protective layer 5 is provided, this is arbitrary. In the case of providing the protective layer 5 or a film, plate material or the like corresponding thereto, the manufacturing method can be performed in the order opposite to that of the above embodiment. For example, the auxiliary electrode 4, the insulating layer 3, the sensor electrode 21, the wiring part 22, and the substrate 1 can be manufactured in this order on the protective layer 5. As a method for forming each member, the same method as described above can be adopted.

  In the above embodiment, as shown in FIG. 3, the areas of the sensor electrodes 21 are different. For example, as shown in FIG. 11, all the sensor electrodes 21 can have the same area. In this way, since the electrostatic capacitance between the sensor electrode 21 and the auxiliary electrode 4 becomes constant, the detection sensitivity at each detection point can be made uniform.

  Examples of the present invention will be described below. However, the present invention is not limited to the following examples.

Here, three examples and one comparative example were produced. In Example 1 shown in FIG. 12A, sensor electrodes made of a conductive tape having a width of 20 mm were arranged on the upper surface of the lower acrylic plate, and the distance between them was set to 10 mm. An auxiliary electrode made of a conductive tape having a width of 30 mm was disposed on the lower surface of the upper acrylic plate, and the gap between them was set to 1 mm. Then, both acrylic plates were fixed with an insulating adhesive material. At this time, the boundary between the two auxiliary electrodes was arranged between the sensor electrodes. In Example 2 shown in FIG. 12B, four auxiliary electrodes having a width of 10 mm are used, two auxiliary electrodes are arranged in the region between the sensor electrodes, and one auxiliary electrode is provided at each of the left and right ends of each sensor electrode. Arranged one by one. That is, the auxiliary electrode is not disposed above the center of the sensor electrode. In Example 3 shown in FIG. 12C, an ITO film was used as the auxiliary electrode. That is, a film formed by sputtering ITO on a PET film having a thickness of 125 μm was used. The surface resistance value of this ITO film was 250Ω. And in the comparative example shown in FIG.12 (d), the auxiliary electrode is not arrange | positioned. The details of each material are as follows.
Conductive tape: Teraoka Seisaku "conductive copper thin adhesive tape 8323"
Adhesive: "ST-415" manufactured by Sumitomo 3M Co., Ltd. 120μm thick acrylic plate: 1mm thick Static when touching the upper part of the center of the sensor electrodes and touching between the sensor electrodes using Examples and Comparative Examples above The electric capacity was calculated as a value converted into a digital value using a microcomputer (Programmable System-on-Chip (PSoC) CY8C24994-24LTXI) manufactured by Cypress Semiconductor (Cypress Semiconductor). The results are as follows.

センサ電極間をタッチしたときの数値は、２つのセンサ電極それぞれで検出された静電容量である。上記の結果から、実施例１〜３では、センサ電極間をタッチしたときには、両センサ電極において、ほぼ２分割された静電容量が検出されていることが分かる。実施例３のような比較的抵抗の高い補助電極を用いた場合でも両センサ電極にほぼ２分割された静電容量が検出されている。したがって、センサ電極間に隙間があっても、これを埋める補助電極が配置されていれば、検出感度が低下しないことが分かる。これに対して、補助電極を有していない比較例では、両センサ電極での静電容量の検出量が小さかった。

The numerical value when touching between the sensor electrodes is the capacitance detected by each of the two sensor electrodes. From the above results, it can be seen that in Examples 1 to 3, when the sensor electrodes were touched, the capacitance divided into two was detected in both sensor electrodes. Even when an auxiliary electrode having a relatively high resistance as in the third embodiment is used, the capacitance divided into two is detected for both sensor electrodes. Therefore, even if there is a gap between the sensor electrodes, it can be seen that the detection sensitivity does not decrease if the auxiliary electrode that fills the gap is arranged. On the other hand, in the comparative example which does not have an auxiliary electrode, the detection amount of the electrostatic capacitance in both sensor electrodes was small.

21 Sensor electrode 22 Wiring part 3 Insulating layer 4 Auxiliary electrode

Claims (7)

An insulating layer;
A plurality of sensor electrodes disposed on one side of the insulating layer;
A plurality of wiring portions disposed on one side of the insulating layer and connected to the sensor electrodes;
A plurality of auxiliary electrodes respectively disposed at positions facing the sensor electrodes on the other surface side of the insulating layer;
With
A touch switch, wherein a boundary between adjacent auxiliary electrodes is arranged in a region between adjacent sensor electrodes.   The touch switch according to claim 1, wherein the plurality of auxiliary electrodes are spread above a reference region in which the plurality of sensor electrodes are arranged.   The touch switch according to claim 1, wherein a gap between adjacent auxiliary electrodes is 10 μm to 3 mm.   The touch switch according to claim 1, wherein the sensor electrode is formed by arranging metal wires in a mesh shape.   The touch switch according to claim 1, wherein the wiring portion is formed of at least one metal wire. Each of the auxiliary electrodes has at least a part of an edge extending so as to form irregularities in the surface direction,
6. The touch switch according to claim 1, wherein a boundary between the adjacent auxiliary electrodes is formed such that the concave and convex portions mesh with each other at a predetermined interval.   The touch switch according to claim 1, wherein areas of the plurality of sensor electrodes are the same.

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