JP2023023773A - Sensor electrode - Google Patents

Abstract

To provide a new touch sensor capable of following a surface of an article having flexibility and a complicated shape, capable of functioning as a switch even if it is bent, and having high pattern accuracy and a degree of freedom of a pattern.SOLUTION: A touch sensor electrode includes an insulation layer 3 and conductive layers 2, 4 having a conductive portion of two layers arranged on both sides of the insulation layer 3. At least one layer of the conductive layers 2, 4 is constituted as a conductive fabric layer 2 that is composed only of the conductive portion formed into a desired shape of conductive knitted fabric of high-density tissue composed of a double knit using a conductive yarn, for example.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a sensor electrode and a manufacturing method thereof. More specifically, the present invention relates to a sensor electrode having high pattern accuracy and pattern flexibility, which is composed of a laminate composite including a conductive fabric layer made of only conductive yarn.

With the development of the information society, in recent years, large electronic devices such as personal computers and televisions that use touch sensors, small electronic devices such as car navigation systems, mobile phones, smartphones, tablets, and electronic dictionaries, and display devices such as OA and FA equipment. is prevalent.

A touch sensor is usually provided on the display surface of the touch panel. When a stylus, finger, or the like touches (contacts) a position of an object such as a button displayed on the display, the position is detected by a touch sensor. Therefore, the user can perform operations more intuitively than, for example, the conventional method using a keyboard or mouse.

As a touch sensor system, several systems such as a resistive film system and an electromagnetic induction system have been proposed and put into practical use. One of these touch sensor systems is called a capacitive system. A capacitive touch sensor typically comprises a conductive film to which a high frequency voltage is applied. When the user touches any position of the conductive film with, for example, a finger, conduction occurs at that position and current flows. By detecting the current flow, the touched position (touch position) is specified.

As capacitive touch sensors, a type called a surface type and a type called a projection type are currently in practical use. In the surface type, for example, a voltage is applied to electrodes arranged at each of the four corners of the conductive film. When a user's finger touches any position on the conductive film, current flows between the electrode and the finger. A difference in resistance value between each of the four corner electrodes and the finger causes a difference in the amount of current flowing between those electrodes and the finger. A touch position is specified based on the difference.

On the other hand, the projection type has a structure in which a supporting substrate on which a matrix-like electrode layer is formed is covered with a protective insulating resin. When the user's finger touches any position on the conductive film, the capacitance of the electrode in the area centered on the touched position changes. The center point of the touched position is specified by the control IC detecting the change for each electrode.

As described above, in the capacitive touch sensor, the user can perform an input operation on the terminal device by directly touching the electrically conductive membrane with the finger. Compared to touch sensors, it is easier. Furthermore, the projected capacitive touch sensor can detect the position of each of the multiple points when touched at multiple points at the same time. is possible. Due to such convenience, projection-type capacitive touch panels are widely used in smartphones (PDA (Personal Digital Assistant) equipped with mobile phone functions) and pad-type PCs, which are rapidly gaining popularity these days. there is

In addition to panel-type devices such as touch panels, in recent years, sensors have been proposed that can follow a free-form surface such as the surface of an article having a complicated shape. For example, a touch sensor using a cloth woven with conductive yarn (Patent Document 1; Japanese Patent Application Laid-Open No. 2006-234716) and a touch sensor device using a conductive fabric woven with conductive fibers as a touch sensor (Patent Document 2) ; JP-A-2011-102457) and the like have been proposed. In addition, a film-like touch panel sensor using a synthetic resin film as a base material has also been proposed, for example, as in Patent Document 3 (Japanese Patent Application Laid-Open No. 2013-206315).

However, the touch sensor disclosed in Patent Document 1 using conductive fibers has a low degree of freedom in patterning and is difficult to manufacture. Also, it may be difficult to increase the sensitivity. In the touch sensor device of Patent Document 2, which uses a conductive material that is woven in a pattern using conductive threads and insulating threads, it is difficult to form a pattern other than a straight line, so its application is limited. In addition, the pattern accuracy is lowered due to bending, shrinkage, etc., and the sensor accuracy is not stable. Furthermore, the touch sensor of Patent Document 3, which uses a synthetic resin film as a base material, has the drawback of lacking flexibility and texture.

With the aim of providing a touch sensor device that has flexibility similar to that of fabric, can be attached to the surface of an article with a complicated shape, and can function as a switch even when bent, the inventors of the present application have made the following: We have proposed a composite material having an electrode part that constitutes a touch sensor between a laminate composed of a fibrous base material and a urethane resin layer (Patent Document 4; Japanese Patent Application No. 2016-003128), but even higher pattern accuracy and pattern There is a demand for development of a touch sensor having a degree of freedom and a sensor electrode used therefor.

JP-A-2006-234716 JP 2011-102457 A JP 2013-206315 A Japanese Patent Application No. 2016-003128

INDUSTRIAL APPLICABILITY The present invention is suitable for touch sensors, etc., which are flexible and can follow objects with complicated shapes, can function as a switch even when bent, and have high pattern accuracy and pattern freedom. An object of the present invention is to provide a novel sensor electrode that can be used.

As a result of intensive studies, the present inventors have found that the dimensional accuracy and degree of freedom of the pattern are significantly increased by using a conductive fabric consisting only of a conductive portion for at least one of the conductive layers that constitute the electrode. I have perfected my invention.

That is, the present invention relates to a sensor electrode described below.
(1) A laminate composite comprising an insulating layer and conductive material layers having two conductive portions disposed on both sides of the insulating layer, wherein at least one of the conductive material layers has only a conductive portion. A sensor electrode, which is a composed conductive fabric layer.

(2) The sensor electrode according to (1), wherein the conductive cloth layer is composed only of a conductive portion formed by forming a conductive knitted fabric using conductive yarn into a desired shape.
(3) The sensor electrode according to (2), wherein the conductive knitted fabric is composed of a high-density structure having a metal distribution area ratio of 60% or more.

(4) The sensor electrode according to any one of (1) to (3), wherein the conductive material layer includes the conductive fabric layer and a base layer having a conductive pattern formed thereon.
(5) The sensor electrode according to any one of (1) to (4), wherein the conductive fabric layer is formed on a support.

(6) The sensor electrode according to (5), wherein the support is made of fabric, and a thermoplastic resin layer is formed on one side of the support.
(7) The sensor electrode according to any one of (1) to (6), wherein the laminated composite has a thickness of 1.5 mm or less.
(8) The sensor electrode according to any one of (1) to (7), which is formed by vacuum forming.

Since the sensor electrode of the present invention includes a conductive material layer that can be patterned by cutting a conductive fabric composed only of a conductive portion into an arbitrary shape, the dimensional accuracy of the pattern can be improved. If a method of forming a pattern by cutting is used, it becomes easy to increase the degree of freedom in the pattern shape of the electrode. Moreover, since the thickness of the sensor electrode of the present invention can be reduced, a thinner touch sensor can be provided. Furthermore, vacuum forming can also be enabled.

The sensor electrode of the present invention is useful for various touch sensors, and the touch sensor using the sensor electrode of the present invention has wide applicability as various switches. Since it has flexibility comparable to general synthetic leather, it can be made to follow the surface of an article with a complicated shape, and can function as a switch even when it is bent. Therefore, it can be used as interior parts for automobiles, aircraft, trains, etc., and covers for smartphones, tablets, laptop computers, etc.

It is a schematic diagram showing an example of the electrode for sensors of the present invention. It is a schematic diagram showing an example of the electrode for sensors of the present invention. It is a schematic diagram showing an example of the electrode for sensors of the present invention. It is a schematic diagram showing an example of the electrode for sensors of the present invention. It is a schematic diagram showing an example of the electrode for sensors of the present invention. It is a schematic diagram showing an example of the electrode for sensors of the present invention.

The sensor electrode of the present invention is composed of a laminate composite including an insulating layer and conductive material layers having two conductive portions disposed on both sides of the insulating layer, and at least one of the conductive material layers is a conductive fabric layer composed only of a conductive portion.

1. Conductive Material Layer (1) Conductive Cloth Layer Composed Only of Conductive Part In the laminate composite, of the two conductive material layers arranged on both sides of the insulating layer, at least one layer is composed only of the conductive part. It is a conductive fabric layer. The conductive portion in the conductive fabric layer is preferably formed of a conductive knitted fabric using conductive yarn.

(i) Conductive yarn Examples of the conductive yarn include thin metal wires, conductive fibers, filaments made of conductive fibers, and the like.
Gold, silver, copper, nickel, chromium, tin, etc. are mentioned as a metal used for a metal fine wire. The thickness of the thin line is preferably about 50-200 dtex.

Examples of conductive fibers include fibers made of conductive polymers, metal fibers, carbon fibers, and the like. Specific examples of conductive polymers include polyacetylene, poly(p-phenylene vinylene), polypyrrole, polythiophene, polyaniline, poly(p-phenylene), and the like. Although the thickness (single fineness) of the conductive fiber is not particularly limited, it is preferably 5 to 420 dtex.

In addition, as the conductive fiber, a non-conductive fiber which is a core thread and is plated with a metal can also be used. Non-conductive fibers include nylon fibers, vinylon fibers, polyester fibers, polyolefin fibers, acrylic fibers, vinylidene chloride fibers, polyurethane fibers, aramid fibers, and the like.

Gold, silver, copper, nickel, chromium, tin, zinc, alloys thereof, and the like are examples of metals for plating when non-conductive fibers are plated with metal. The plating method includes a dry method and a wet method. Examples of dry methods include vapor deposition and sputtering, and examples of wet methods include electroless plating and electroplating.

The thickness of the metal film formed by such plating is preferably 0.075 μm to 0.50 μm, more preferably 0.1 μm to 0.3 μm. The obtained conductive fiber preferably has a resistance value of 10000 Ω/m or less, more preferably 1000 Ω/m or less.

A conductive resin-coated yarn obtained by coating a non-conductive fiber with a conductive material such as carbon can also be used as the conductive fiber. A specific example thereof is conductive yarn (trade name: Metalian, manufactured by Teijin Limited) in which nylon fibers are coated with carbon.

A filament made of conductive fibers may be a monofilament or a multifilament. The filament thickness (total fineness) is not particularly limited, but is preferably about 10 to 150 dtex. Although the number of filaments is not particularly limited, it is preferably about 1 to 100.

(ii) Conductive Knitted Fabric The conductive knitted fabric is formed by knitting conductive yarns by a normal method, but it is preferable to form a high-density structure by a method such as double knitting. By forming a high-density structure, it is possible to generate a large change in capacitance due to compressive deformation of the conductive knitted fabric. It is possible to make the sensor (sensor electrode) thinner (the thickness of the laminated composite is, for example, 1.5 mm or less, more preferably 1.0 mm or less).

The density of the conductive knitted fabric referred to here indicates the metal distribution area ratio in the knitted fabric structure. The metal distribution area ratio is indicated by the area ratio in which the metal component is distributed in a planar image of the surface of the knitted fabric structure. A high-density structure has a metal distribution area ratio of preferably 60% or more, more preferably 80% or more.

INDUSTRIAL APPLICABILITY The sensor electrode of the present invention is used as a pressure sensor, and is used in a system that detects changes in capacitance by converting them into changes in pressure.
The capacitance depends on the electrode area and the distance between the electrodes, but when a conductive knitted fabric is used for the electrodes, the electrode area depends on the conductive yarn density (metal distribution area ratio), and the distance between the electrodes depends on the thickness of the insulating layer and the conductive knitted fabric. is determined by the surface roughness of the

Knitted fabrics are made up of loops of yarn, so they have unevenness on the surface. When these unevennesses are crushed when compressed, the distance between electrodes changes and the capacitance changes. Since the electrode area is increased and the capacitance is increased, the absolute amount of the capacitance change described above is increased. Therefore, by using a high-density conductive knitted fabric as an electrode, a large capacitance change can be detected only by deformation of the electrode. Therefore, it is not necessary to use a cushioning insulating layer. Foamed sponge with a thickness of 2 to 5 mm is usually used for the cushioning insulating layer, but in the present invention, by adopting a conductive knitted fabric with a high-density structure, a thin insulating layer of 150 μm or less can be obtained as described later. , a sensor electrode having a sufficiently high-precision detection capability can be obtained, so that the thickness of the touch sensor can be reduced.

In order to make the conductive knitted fabric have such a high-density structure, it is preferable to form the knitted fabric by double knitting. Specifically, it can be produced by knitting by a method such as making a smooth texture with a circular knitting machine, increasing the number of gauges (high gauge, for example, 12 threads/inch or more), or the like.

The conductive knitted fabric is preferably knitted with 35 to 45 courses/inch and 35 to 45 wales/inch. Moreover, the thickness of the conductive knitted fabric is preferably about 200 to 500 μm.

(iii) Conductive fabric layer The conductive fabric layer, which is composed only of the conductive part, is formed (cut) into a desired shape such as a band, wave, or ribbon, and placed on the insulating layer. formed by Since the pattern can be formed by cutting into an arbitrary shape, the dimensional accuracy of the pattern can be improved. In addition, since the pattern is formed by cutting, the degree of freedom of the shape is high. The conductive fabric layer may be placed on only one side of the insulating layer or on both sides of the insulating layer.

The conductive portion of the conductive fabric layer may be linear such as strip, wavy, or ribbon, or may be circular, but is preferably linear. Therefore, it is preferable to use the conductive knitted fabric by cutting it into a strip shape, a wave shape, a ribbon shape, or the like.
When cutting linearly, the width is preferably about 5 to 20 mm. Further, when arranged on the insulating layer, it is preferable to arrange the linear conductive knitted fabrics in parallel at a pitch of 5 to 20 mm.

(2) Base material layer having a conductive pattern formed In the laminated composite, among the two conductive material layers arranged on both sides of the insulating layer, as a conductive material layer other than the conductive fabric layer, any conductive layer can also be placed. The conductive material layer other than the conductive fabric layer does not have to be composed only of the conductive portion, and is not particularly limited as long as it has a conductive portion in at least a part thereof, but is preferably formed with a conductive pattern. and a base material layer.

Specifically, a base material having a conductive pattern formed on at least a part thereof can be mentioned. Examples of base materials include fabrics and films. The conductive pattern may be formed on at least a part of the base material, and may be formed on the entire surface of the base material or only on a part of the base material.

(i) Cloth with Conductive Pattern Formed When fabric is used as the base material, the method of forming a conductive pattern on at least a part of the fabric includes at least one conductive thread or a thread containing conductive fibers. Examples include a method of weaving or knitting using a part, or a method including electroless plating. Among these methods, the method of applying electroless plating to the non-conductive yarn forming the fabric is preferable because the degree of freedom of the conductive pattern is higher.

Conductive yarns used in methods involving weaving or knitting include metal yarns, conductive resin-coated yarns, and the like. Metals used for the metal threads include copper, nickel, tin, and silver. A specific example of the conductive resin-coated yarn is a conductive yarn in which nylon fibers are coated with carbon (trade name: Metalian, manufactured by Teijin Limited). Although the thickness of the conductive thread is not particularly limited, it is preferably 10 to 170 dtex.

Examples of conductive fibers include fibers made of conductive polymers, metal fibers, carbon fibers, and the like. Specific examples of conductive polymers include polyacetylene, poly(p-phenylene vinylene), polypyrrole, polythiophene, polyaniline, poly(p-phenylene), and the like. Although the thickness of the conductive fiber is not particularly limited, it is preferably 10 to 170 dtex.

Yarns containing conductive fibers (multifilaments) include yarns made of conductive fibers and yarns partially using conductive fibers. The thickness of the thread containing conductive fibers is not particularly limited, but is preferably 10 to 170 dtex. The weaving or knitting method is not particularly limited, and conventionally known methods are used.

Examples of the method including electroless plating include a method of forming a conductive pattern by applying electroless plating to a cloth on which a pattern having catalytic activity for plating is formed.
More specifically, after printing a plating resist on a cloth to form a resist layer having a pattern opposite to the desired conductive pattern, an electroless plating catalyst is applied to the cloth and then subjected to reduction treatment to activate the plating catalyst. forming the desired pattern of metal having a

The resist layer is then removed. A method for removing the resist layer is not particularly limited, and a known method can be used. For example, immerse in a 0.1% NaOH aqueous solution, use an ultrasonic cleaner (eg, trade name: US CLEANER, manufactured by AS ONE Corporation), etc., bath temperature about 25 to 35 ° C. (more preferably about 30 ° C.), The resist layer can be removed with a cleaning time of 1 to 2 minutes.
Then, a desired conductive pattern can be formed on the fabric by subjecting it to electroless plating treatment.

The plating resist is not particularly limited as long as it has chemical resistance to the catalyst and reducing solution used in the electroless plating process.
As a method for forming the reverse patterned plating resist layer, it is preferable to harden the reversed patterned plating resist. The curing method may be either heat curing or ultraviolet curing. Therefore, the plating resist of the present invention may be of a thermosetting type or an ultraviolet curable type.

Solvents, binder resins, coloring components, additives and the like are usually appropriately blended in plating resists as required. As the binder resin, epoxy-based, polyester-based, acrylic-based, isocyanate-based resins, and the like can be used. The binder resin may be of a thermosetting type or an ultraviolet curable type.

Known methods such as gravure printing, screen printing, photolithography, gravure offset printing, flexographic printing, and inkjet printing can be applied as printing methods for printing the plating resist on the fabric. Among these, screen printing, inkjet printing, and the like are preferable.

Examples of metals having catalytic activity for plating include copper, nickel, silver, tin, rhodium, palladium, gold, and platinum. Palladium, which has high catalytic activity for plating, is preferably used.

Electroless plating catalysts include solutions containing metal ions that can be reduced to metals having plating catalytic activity. Such metal ions include palladium ions, and examples of compounds that generate palladium ions include palladium chloride, palladium bromide, palladium acetate, palladium sulfate, palladium nitrate, palladium acetylacetonate, and palladium oxide. Among them, palladium chloride, which is widely used as a general catalyst, is preferably used because it is relatively easy to obtain.

Although the solvent used for the metal ion-containing solution is not particularly limited, it is preferably water.
The metal ion concentration in the metal ion-containing solution is preferably 30-80 g/L, more preferably 30-50 g/L.

The reaction temperature when the fabric is brought into contact with the metal ion-containing solution is 10°C to 80°C, preferably 10°C to 50°C. The contact time of the metal ion-containing solution is preferably 10 seconds to 800 seconds, more preferably 30 seconds to 500 seconds.

After contact with the metal ion-containing solution, the fabric is preferably washed with water to remove non-specifically attached metal ions. As the water washing method, a known washing method can be applied.

As the reduction method, a method of contacting the cloth to which metal ions are adsorbed with an acidic treatment liquid containing a reducing agent (hereinafter referred to as a reduction treatment liquid) is preferable. Examples of the reducing agent used in the acidic treatment liquid containing the reducing agent include dimethylamine borane, sodium hypophosphite, hydrazine, diethylamine, ascorbic acid, hydrofluoroborate (tetrafluoroboric acid), and the like.

Also, the concentration of the reducing agent in the reducing treatment liquid is preferably 5 to 20 g/L. A solvent used for the reduction treatment liquid is not particularly limited, but water or the like is preferable. The pH of the reduction treatment solution is preferably 6 or less, more preferably 2 to 6, still more preferably 3 to 5.9.

The time for which the fabric is brought into contact with the reducing treatment solution is 30 seconds to 600 seconds, preferably 60 seconds to 300 seconds. The contact temperature is 10°C to 80°C, preferably 30°C to 50°C. After being brought into contact with the reducing treatment liquid, the fabric is washed with water to remove non-specifically adhered reducing agent. After the reduction treatment, the fabric is washed and dried as necessary to obtain a fabric on which a desired pattern having catalytic activity for plating is formed.

A known electroless plating method can be used as the electroless plating method. Electroless plating metals include at least one metal selected from the group consisting of copper, nickel, tin, and silver, or alloys thereof (for example, alloys of copper and tin). Copper and nickel are preferred, and copper is particularly preferred.

An existing plating bath can be used for electroless plating, and the fabric may be immersed in this plating bath. The reaction time and temperature of the electroless plating can be appropriately adjusted according to the thickness of the plated film, but the preferred plating time is 5 to 20 minutes and the preferred temperature is 40 to 50°C.

The film thickness of the electroless plated film (conductive pattern) thus obtained is preferably 0.1 to 10 μm, more preferably 0.2 to 7 μm.
After the electroless plating film is formed, the cloth can be washed with water to remove the non-specifically adhered plating solution, if necessary.

(ii) Film Substrate with Conductive Pattern Formed When a film is used as the substrate having the conductive pattern, a preferred film is a synthetic resin film such as polyethylene terephthalate.

Although the thickness of the synthetic resin film is not particularly limited, it is preferably 10 to 200 μm, more preferably 50 to 100 μm.

Methods for forming a conductive pattern on a film substrate include, for example, a method of printing a conductive pattern on a film substrate using a conductive ink, a method of disposing a patterned conductive member on a film substrate, and a method of disposing a patterned conductive member on a film substrate. Examples include a method of forming a conductive pattern on a material by metal plating.

The method of printing the conductive pattern is not particularly limited, and known methods such as gravure printing, screen printing, photolithography, gravure offset printing, flexographic printing, and inkjet printing can be applied. Among these, inkjet printing, gravure printing, screen printing, etc. are preferable.

Conductive inks include conductor-containing resin compositions, conductive polymer compositions, and the like. As the conductive member, a film or film made of a conductive polymer composition or a metal foil (hereinafter referred to as "conductive film"), or a fiber-based material such as a fine metal wire, conductive fiber, or cloth made of conductive fiber ( hereinafter referred to as "conductive fiber-based material").

The conductive ink can form conductive portions in a pattern by a printing method. When using a conductive member made of a conductive film or a conductive fiber-based material, a conductive pattern can be formed by punching them out in a pattern (patterned conductive member) and arranging them. Alternatively, the conductive pattern may be formed directly on the film substrate by metal plating.

A conductor-containing resin composition that can be used as a conductive ink is a resin composition containing a conductor, and more specifically, a composition in which a conductor such as metal fine particles or carbon particles is blended with a binder resin. be. Examples of conductors include metal fine particles and carbon particles. Metal fine particles include gold, silver, copper, zinc, nickel, tin, aluminum and their oxides. Preferred among these are silver, copper and nickel.

Examples of binder resins include polyester resins, polyurethane resins, polycarbonate resins, polyether resins, polyamide resins, polyamideimide resins, polyimide resins, acrylic resins, and the like. Preferred among these are polyester resins and polyurethane resins.

In addition, solvents, dispersants, reducing agents, curing agents, surface control agents, thickeners, etc. may be blended as additives.
A preferable compounding ratio of the conductor is preferably 80 to 99% by mass, more preferably 85 to 95% by mass, based on the total amount of the conductor-containing resin composition.

The conductive polymer composition is mainly composed of a conductive polymer (conductive polymer). Examples of conductive polymers include PEDOT/PSS (thiophene-based conductive polymer), polyacetylene, poly(p-phenylene vinylene), polypyrrole, polythiophene, polyaniline, poly(p-phenylene), and the like.

A conductive film that can be used as a conductive member is a film made of a conductive polymer composition. Conductive polymers used in the conductive polymer composition include PEDOT/PSS, polyacetylene, poly(p-phenylenevinylene), polypyrrole, polythiophene, polyaniline, and poly(p-phenylene).

The conductive polymer composition may also contain a binder resin (non-conductive polymer), a conductivity improver, a solvent, a cross-linking agent, a surface conditioner, a thickener, and the like. The blending ratio of the conductive polymer in the conductive polymer composition is preferably 10 to 99% by mass, more preferably 20 to 95% by mass. A film thickness of 10 to 200 μm is preferable.

Metal foils include foils made of metals such as gold, silver, copper, nickel, chromium, and tin. The thickness of the metal foil is preferably 10-200 μm, more preferably about 10-100 μm.

Examples of conductive fiber-based materials include thin metal wires, conductive fibers, and fabrics made of conductive fibers. Gold, silver, copper, nickel, chromium, tin, etc. are mentioned as a metal used for a metal fine wire. The thickness of the thin line is preferably about 50-200 dtex.

Examples of conductive fibers include fibers made of conductive polymers, metal fibers, carbon fibers, and the like. Specific examples of conductive polymers include polyacetylene, poly(p-phenylene vinylene), polypyrrole, polythiophene, polyaniline, poly(p-phenylene), and the like. Although the thickness of the conductive fiber is not particularly limited, it is preferably 5 to 420 dtex.

In addition, a non-conductive fiber plated with a metal can also be used as the conductive fiber. Non-conductive fibers include nylon fibers, vinylon fibers, polyester fibers, polyolefin fibers, acrylic fibers, vinylidene chloride fibers, polyurethane fibers, aramid fibers, and the like.

Gold, silver, copper, nickel, chromium, tin, zinc, alloys thereof, and the like are examples of metals for plating when non-conductive fibers are plated with metal. The plating method includes a dry method and a wet method. Examples of dry methods include vapor deposition and sputtering, and examples of wet methods include electroless plating and electroplating.

Fabrics made of conductive fibers include woven fabrics, knitted fabrics, non-woven fabrics, and the like made of the conductive fibers described above. A conductive mesh obtained by plating a mesh fabric made of non-conductive fibers with a metal is particularly preferable.

The conductive member made of a conductive mesh may be formed into a pattern by punching, or a patterned conductive member in which a conductive portion is formed by plating a portion of a mesh fabric made of non-conductive fibers in a pattern with a metal. good too.

A method of using a part of a mesh fabric made of non-conductive fibers as an electrode part includes a method of partially applying a plating catalyst by printing and then performing catalyst activation and plating. As another method, there is a method of plating the entire surface of the mesh fabric made of non-conductive fibers, and then removing the metal plating other than the portions to be the electrode portions by etching. As an etching method, a known etching method can be used.

A conductive pattern may be formed by performing a metal plating treatment directly on the substrate. Plating metals include gold, silver, copper, nickel, chromium, tin, zinc, and alloys thereof. The plating method includes a dry method and a wet method. Examples of the conductive pattern forming method include a method of pattern-printing a plating catalyst, and a method of applying a metal plating treatment to the front surface of the substrate and then removing the metal plating from portions other than the conductive portion by etching.

2. Insulating Layer The insulating layer can be formed of an insulating material such as an insulating resin. Although there are no particular restrictions on the standard of insulation, the resistance value is preferably 1×10 ¹¹ Ω/□ or more, more preferably 1×10 ¹² Ω/□, and particularly preferably 7×10 ¹² Ω/□.

Specific examples of insulating resins include acrylic resins, melamine resins, epoxy resins, urethane resins, polyester resins, polyurethane resins, and polyamine resins. Among these, acrylic resins, polyester resins and polyurethane resins are particularly preferred.

Moreover, since the insulating layer needs to insulate the conductive material arranged on both sides, it is preferable that the insulating layer has a non-porous structure. Specific examples include synthetic resin films, and non-porous synthetic resin films made of acrylic resin, polyester resin, polyurethane resin, or the like are particularly preferred.

The thickness of the insulating resin is not particularly limited, but the lower limit is preferably 5 µm or more, more preferably 10 µm or more, still more preferably 20 µm or more, and particularly preferably 30 µm or more, and the upper limit is preferably 150 µm or less, more preferably 150 µm or more. It is 100 μm or less, more preferably 70 μm or less.

In the present invention, when a conductive knitted fabric with a high-density structure is adopted as the conductive fabric layer composed only of the conductive portion, the insulating layer disposed between the two conductive material layers does not need cushioning properties. The sensor electrodes can be designed thin. For example, the thickness of the sensor electrode can be 1.5 mm or less, further 1.3 mm or less, particularly 1.0 mm or less.

3. Support In the laminated composite constituting the sensor electrode of the present invention, a conductive fabric layer composed only of a conductive portion can be formed on a support made of an insulator. That is, the conductive fabric is cut into a desired shape such as a strip, wave, or ribbon, and one or more, preferably a plurality of conductive fabric layers are arranged on a support made of an insulating material, thereby forming a conductive fabric layer composed only of conductive parts. can be formed on the support. As a measure of the insulating property of the support, the resistance value is preferably 1×10 ¹¹ Ω/□ or more, more preferably 1×10 ¹² Ω/□ or more, and particularly preferably 1×10 ¹³ Ω/□ or more.

The support can be formed from fabric, film, or the like. Of these, it is preferable to use cloth.
Fabrics consist primarily of non-conductive yarns. The thread may be a monofilament thread or a multifilament thread formed by bundling a large number of fibers. Although the thickness of the thread is not particularly limited, it is preferably about 10 to 70 dtex in the case of monofilament, and about 10 to 170 dtex in the case of multifilament. In the case of multifilaments, the number of filaments is not particularly limited, but preferably 1 to 100.

Specific examples of fabrics include fiber fabrics such as woven fabrics, knitted fabrics, and non-woven fabrics. Examples of fiber materials include natural fibers such as cotton, hemp, wool and silk, regenerated fibers such as rayon and cupra, semi-synthetic fibers such as acetate and triacetate, polyamide (nylon 6, nylon 66, etc.), polyester ( polyethylene terephthalate, polytrimethylene terephthalate, etc.), synthetic fibers such as polyurethane and polyacryl, etc., and two or more of these may be combined. Among these, fabrics made of synthetic fibers having excellent overall fiber physical properties are preferred, and fabrics made of commonly used synthetic fibers such as polyester fibers and nylon fibers are more preferred.

The fiber fabric may be subjected to dyeing, antistatic treatment, flame-retardant treatment, calendering, or the like, if necessary. The thickness of the fabric is not particularly limited. Especially preferably, it is 0.5 mm or less.

Examples of films include synthetic resin films such as polyethylene terephthalate. Although the thickness of the film is not particularly limited, it is preferably about 10 to 200 μm, more preferably about 50 to 100 μm.

4. Thermoplastic resin layer The support can be provided with a specific thermoplastic resin layer on at least one side thereof. In particular, it is preferable to select a fabric as the support and attach a thermoplastic resin film to one side of the fabric. When such a fabric having a thermoplastic resin layer on at least one side thereof is used as a support, it becomes possible to three-dimensionally form (vacuum form) the laminated composite obtained thereby.

By using a fabric as a support and attaching a thermoplastic resin film, it is possible to obtain a configuration in which the conductive fabric layer portion composed only of the conductive portion is hardly deformed even when the conductive material layer is elongated and deformed. Thereby, high pattern accuracy can be maintained.

The present invention using a laminated composite with a conductive fabric layer also has the advantage of allowing vacuum forming. Laminates containing knitted fabric layers such as conductive fabric layers may be difficult to suck during vacuum forming due to their air permeability. And it can play a role of shape maintenance. Therefore, it is possible to perform vacuum forming and increase the degree of freedom in the shape of the product.

Examples of the thermoplastic resin layer that is attached to the support include films made of polyester-based resins, polyolefin-based resins, vinyl chloride resins, polyurethane resins, and the like. The thickness of the thermoplastic resin layer is not particularly limited, but the lower limit is preferably 5 μm or more, more preferably 10 μm or more. Also, the upper limit is preferably 200 μm or less, more preferably 100 μm or less, still more preferably 40 μm or less, and particularly preferably 20 μm or less.

The thermoplastic resin layer is preferably an insulator. As a standard of insulation, the resistance value is preferably 1×10 ¹¹ Ω/□ or more, more preferably 1×10 ¹² Ω/□. Although the upper limit of the resistance value is not particularly limited, it is preferably 6×10 ¹² Ω/□ or less.

4. Layer Configuration Schematic diagrams of an example of the sensor electrode of the present invention are shown in FIGS. In FIG. 1, 1 is a laminated composite, 2 is a conductive material layer (conductive fabric layer composed only of conductive parts), 3 is an insulating layer, and 4 is a conductive material layer (a base layer on which a conductive pattern is formed). , 5 represents a support, and 6 represents a thermoplastic resin film.

An example of the sensor electrode of the present invention is shown in FIG. consists of That is, at least two layers of conductive material layers are arranged on both sides of the insulating layer. At least one of the conductive material layers on both sides of the insulating layer is a conductive fabric layer 2 composed only of a conductive portion. Only one or both of the conductive fabric layers may be composed of only the conductive portion.

In FIG. 1, on one side of the insulating layer 3, there is formed a conductive fabric layer 2 composed only of a conductive portion, in which a plurality of ribbon-like conductive fabrics made of only conductive yarn are arranged in parallel. A base layer 4 having a conductive pattern formed thereon can be arranged as a conductive material layer on the other side of the insulating layer (FIGS. 1 and 2). Also, this conductive material layer can be a conductive fabric layer 2 composed only of a conductive portion similar to that on the opposite side (FIG. 3).

A conductive fabric layer 2, consisting only of conductive parts, can be placed on a support 5 (Fig. 2). The conductive fabric layer 2 formed on the support 5 and composed only of the conductive portion is overlaid so that the conductive portion is in contact with the insulating layer 3 . In this case, therefore, a conductive fabric layer 2 consisting only of conductive parts is formed between the support 4 and the insulating layer 3 .

In the case where the conductive fabric layer 2 composed only of the conductive part is arranged on the other side of the insulating layer 3, the conductive fabric layer 2 formed on the support 5 can be superimposed (Fig. 3). Also in that case, they are overlapped so that the conductive portion is in contact with the insulating layer (FIG. 3).

When the conductive fabric layer 2 composed only of the conductive portion is provided on both sides of the insulating layer, it is preferable that the conductive portions on both sides are arranged in parallel with a strip-shaped or ribbon-shaped line. When the conductive fabric layers 2 having linear conductive portions are placed on both sides of the insulating layer, they can be superimposed so that the conductive portions cross each other (FIG. 3). As a result, it is possible to detect the degree of compressive deformation at the intersecting portion, and to function as a pressure sensor.

Similarly, when the conductive fabric layer 2 composed only of the conductive part is arranged on one side of the insulating layer, and the base material layer 4 on which the conductive pattern is formed is arranged on the other side (FIGS. 1, 2, 4, etc.), the linear can be overlapped so that the conductive portions and the conductive patterns of the layers intersect with each other.

When fabric is used as the support 5 and the thermoplastic resin film 6 is attached, the conductive fabric layer 2 is arranged on the support side. 6 can be laminated and arranged on the insulating layer in order (Fig. 4a).

On the other hand, when fabric is similarly used as the support 5 and the thermoplastic resin film 6 is attached, the conductive fabric layer 2 is arranged on the thermoplastic resin film side. The plastic resin film 6/support 5 can also be laminated and arranged on the insulating layer in this order (Fig. 4b).

In addition, a base layer having a conductive pattern formed thereon can be arranged on the opposite side of the insulating layer. (Fig. 5a). The thermoplastic resin layer can also be placed on the insulating layer side, in which case the thermoplastic resin layer can play the role of the insulating layer (FIG. 5b). If the thermoplastic resin layer serving as an insulating layer is integrated in advance with the conductive material layer using cloth as the base material, vacuum forming becomes possible.

If the insulating layer is superimposed on both sides with a conductive fabric layer consisting only of the conductive part, the thermoplastic resin layer can be arranged on the side opposite to the conductive part (outside the support) (Fig. 6a). A thermoplastic layer can also be placed between the fabric of the support and the conductive part (Fig. 6b). Further, of the conductive material layers arranged on both sides of the insulating layer, one conductive material layer has a thermoplastic resin layer arranged on the side opposite to the conductive portion (outside the support), and the other conductive material layer has A thermoplastic layer may be placed between the support fabric and the conductive portion (Fig. 6c). Three-dimensional molding (vacuum molding) becomes possible by providing a thermoplastic resin layer.

The thickness of the sensor electrode of the present invention is preferably 1.5 mm or less, more preferably 1.0 mm or less. In the present invention, a conductive fabric layer consisting only of a conductive portion is employed, and a conductive knitted fabric with a high-density structure is employed, whereby a large change in capacitance can be caused by compressive deformation. Therefore, the insulating layer does not need to have cushioning properties, and the thickness of the sensor electrode can be reduced.

5. Method for Producing Sensor Electrode The method for producing the sensor electrode of the present invention is not particularly limited, but it is preferable to first form a conductive material layer and then laminate it with an insulating layer. When the conductive material layer is composed of a conductive fabric layer composed only of a conductive portion, a hot-melt film may be laminated on one side of the conductive fabric layer in advance by a heat press or the like, and then cut into a desired shape. can.

When the conductive material layer is composed of a conductive fabric layer, a support, and optionally a thermoplastic resin layer, the conductive fabric layer, the support, and the thermoplastic resin layer are laminated together using a hot-melt film. be able to. For example, after a hot-melt film is laminated on a support in advance by a heat press or the like, a thermoplastic resin layer is thermocompression bonded onto the hot-melt film, and the hot-melt film is laminated in advance by a heat press or the like. After that, a conductive fabric layer cut into a desired shape can be thermocompression bonded.

Examples of hot-melt films include polyurethane-based, polyamide-based, polyester-based, and polyolefin-based films, and the thickness is not particularly limited, but is preferably about 10 to 100 μm.

When fabric is selected as the support and a laminate of thermoplastic resin layers is used, three-dimensional molding can be performed by vacuum forming. As a specific method of vacuum forming, a conductive material layer including a conductive fabric layer, a support and a thermoplastic resin layer is heated with a heater to plasticize the thermoplastic resin layer and then placed on a mold. Then, it is molded and cooled by vacuum suction from the inside of the mold. After the thermoplastic resin layer has solidified, it is released from the mold to obtain a three-dimensional molded product. Then, by laminating with a three-dimensionally molded article comprising an insulating layer vacuum-formed by the same method and mold, a laminated composite having a desired three-dimensional shape can be obtained.

When the thermoplastic resin layer is used as an insulating layer as shown in FIG. 5b, the thermoplastic resin layer is attached to the base material layer on which the conductive pattern is formed, vacuum-molded to obtain a three-dimensional molded product, and then vacuum-molded separately. A three-dimensional molded product comprising a laminated composite can be obtained by laminating a three-dimensional molded product comprising a conductive material layer including a conductive fabric layer, a support and a thermoplastic resin layer.

In addition, a method of vacuum forming a laminated composite obtained by laminating a conductive material layer and an insulating layer in advance to produce a sensor electrode, and a method of vacuum forming the conductive material layer and the insulating layer separately and then stacking them. Any method, such as a method of producing a sensor electrode together, may be used.

The present invention will be described below with reference to examples, but the present invention is not limited by these examples.

<Example 1>
1. Conductive Material Layer Having Conductive Part A conductive material layer having a conductive part was produced using each material and method described below.
(1) Conductive Cloth Layer Consisting Only of Conductive Part A conductive knitted fabric using conductive yarn was cut into strips to form a conductive fabric layer. Ag-plated yarn (manufactured by Seiren Co., Ltd., metal film thickness 1.5 μm; resistance value 350 Ω/m; core yarn polyester) was used as the conductive yarn. This conductive yarn is a multifilament yarn having 12 filaments and a total fineness of 40 dtex.

Using the above conductive yarn, a smooth texture was formed by a circular knitting machine to obtain a conductive knitted fabric (thickness: 300 μm; resistance value: 0.6×10 ⁰ Ω/□) with 40 courses/inch and 44 wales/inch. The obtained conductive knitted fabric was cut into strips having a width of 1 cm to form conductive fabric layers. This conductive knitted fabric has a high-density structure with a metal distribution area ratio of 60% or more.

(2) Support A non-conductive knitted fabric using non-conductive yarn was used as a support. As the non-conductive yarn, polyester yarn (multifilament yarn with 24 filaments; total fineness of 33 dtex) was used. Using this non-conductive yarn, a cotton sheeting structure was made with a circular knitting machine, and a cylindrical non-conductive knitted fabric with 44 courses/inch and 44 wales/inch (thickness 250 μm; resistance value 2.0 × 10 ¹³ Ω/□) was obtained. ). A sheet having a size of 15 cm×15 cm was cut out from the obtained cylindrical non-conductive knitted fabric.

(3) Thermoplastic resin layer A polyurethane film (manufactured by Seiren Co., Ltd., thickness 15 μm; resistance value 5.9×10 ¹² Ω/□) was used as the thermoplastic resin layer. A sheet having a size of 15 cm×15 cm was cut out from a roll-shaped polyurethane film.

(4) Lamination of each material Each obtained material was laminated as follows.
A hot-melt film (manufactured by Nihon Matai Co., Ltd.: Elfan UH203, thickness: 30 μm) was attached to one side of the support using a heat press. Next, a polyurethane film as a thermoplastic resin layer was laminated on the hot-melt film by a heat press.

Furthermore, a conductive fabric layer (1 cm wide strip) obtained by bonding a hot melt film (manufactured by Nihon Matai Co., Ltd.: Elfan UH203, thickness 30 μm) in advance with a heat press is attached to the polyurethane film which is the thermoplastic resin layer. Four pieces were arranged in parallel on the top at a pitch of 2 cm and bonded together by a heat press to form a conductive material layer having a conductive portion. Two conductive material layers having the structure of "conductive cloth layer/thermoplastic resin layer/support" were prepared.

2. Insulating layer A polyurethane film (“Esmer URS” manufactured by Nihon Matai Co., Ltd., thickness 50 μm; resistance value 7.9×10 ¹² Ω/□) was used as the insulating layer. A sheet having a size of 15 cm×15 cm was cut out from a roll-shaped polyurethane film.

3. Evaluation of Vacuum Forming and Dimensional Change A conductive material layer and an insulating layer were formed using a vacuum forming machine. As a mold for molding, a dome-shaped mold having a bottom surface of 7 cm in diameter and a height of 2.5 cm was used. That is, each of the conductive material layer or the insulating layer is heated to 180 ° C. with a heater, placed on a mold, vacuum suctioned from the inside of the mold, molded and cooled, and then released from the mold and the same Three dome-shaped moldings of the mold (two conductive material layers and one insulating layer) were obtained.

In the obtained molded product of the conductive material layer, the width of each of the four strip-shaped conductive fabric layers was measured with a metal rule to determine the rate of change before and after molding. As a result, the rate of change in the width of the conductive fabric layer before and after molding was 4% (the average rate of change of the four conductive fabric layers). By using the conductive cloth layer composed only of the conductive portion as the conductive material layer, it was possible to maintain the dimensional accuracy of the pattern even after the three-dimensional molding.

4. Production of Electrode for Touch Sensor The obtained moldings were stacked in the order of the conductive material layer, the insulating layer, and the conductive material layer. At this time, the two conductive material layers were superimposed so that the conductive fabric layers of the conductive material layers faced the insulating layer side and crossed each other at right angles to form a touch sensor electrode (thickness: 1.2 mm). With the obtained electrode for touch sensor, when the capacitance of the portion where the conductive fabric layers intersect is measured with a capacitance meter, a sufficient change in capacitance is observed, and it functions as a pressure sensor. could be confirmed.

<Comparative example>
1. Conductive Material Layer Having Conductive Part A conductive material layer having a conductive part was produced using each material and method described below.
(1) Cloth Formed with a Conductive Pattern A conductive knitted fabric in which conductive yarns and non-conductive yarns are alternately woven into strips was used as the conductive material layer. Ag-plated yarn (manufactured by Seiren Co., Ltd., metal film thickness 1.5 μm; resistance value 350 Ω/m; core yarn polyester) was used as the conductive yarn. This conductive yarn is a multifilament yarn having 12 filaments and a total fineness of 40 dtex. A polyester yarn (multifilament yarn with 24 filaments; total fineness of 33 dtex) was used as the non-conductive yarn.

Using the above conductive yarn and non-conductive yarn, a circular knitting machine is used to form a conductive pattern in which a strip-shaped conductive part (width 12 mm) and a strip-shaped non-conductive part (width 12 mm) are alternately arranged in parallel. Tubular conductive knitted fabric (thickness: 300 μm; resistance value of conductive part: 0.6×10 ⁰ Ω/□, resistance value of non-conductive part: 2.2× 10 ¹¹ Ω/□). A sheet having a size of 15 cm×15 cm was cut out from the obtained cylindrical conductive knitted fabric.

(2) Thermoplastic resin layer A polyurethane film (manufactured by Seiren Co., Ltd., thickness 15 μm; resistance value 5.9×10 ¹² Ω/□) was used as the thermoplastic resin layer. A sheet having a size of 15 cm×15 cm was cut out from a roll-shaped polyurethane film.

(3) Lamination of each material Each obtained material was laminated as follows.
A hot-melt film (manufactured by Nihon Matai Co., Ltd.: Elfan UH203, thickness: 30 μm) was attached to one side of the conductive material layer using a heat press. Next, a thermoplastic resin layer (polyurethane film) was laminated on the hot-melt film using a heat press.

2. Insulating Layer The thermoplastic resin layer bonded to the conductive material layer was made to function as an insulating layer.

3. Evaluation of Vacuum Forming and Dimensional Change A conductive material layer laminated with a thermoplastic resin layer was formed by a vacuum forming machine. As a mold for molding, a dome-shaped mold having a bottom surface of 7 cm in diameter and a height of 2.5 cm was used. That is, the conductive material layer was heated to 180 ° C. with a heater, placed on a mold, vacuumed from the inside of the mold to form and cool, and then released from the mold to obtain a molded product. .

In the obtained molded product of the conductive material layer, the width of each of the four conductive portions was measured with a metal rule to determine the rate of change before and after molding. As a result, the rate of change in the width of the conductive portion before and after molding was 21% (average rate of change in four conductive portions).

The sensor electrode of the present invention has a wide range of applicability as various switches. Since three-dimensional molding (vacuum molding) is possible, it can be made to conform to the surface of an article with a complicated shape, and even if it is bent, it can function as a switch. Moreover, since compression deformation can be detected, it can be made to function as a pressure sensor. Therefore, it can be used as interior parts for automobiles, aircraft, trains, etc., and covers for smartphones, tablets, laptop computers, etc.

1: Laminated Composite 2: Conductive Cloth Layer Consists Only of Conductive Part 3: Insulating Layer 4: Base Layer Formed with Conductive Pattern 5: Support 6: Thermoplastic Resin Layer

Claims (8)

It is composed of a laminate composite including an insulating layer and conductive material layers having two conductive portions disposed on both sides of the insulating layer, at least one of the conductive material layers being composed only of the conductive portion. A sensor electrode, which is a conductive fabric layer. 2. The sensor electrode according to claim 1, wherein said conductive cloth layer is composed only of a conductive portion formed by forming a conductive knitted fabric using conductive yarn into a desired shape. 3. The sensor electrode according to claim 2, wherein said conductive knitted fabric is composed of a high-density structure having a metal distribution area ratio of 60% or more. The sensor electrode according to any one of claims 1 to 3, wherein the conductive material layer includes the conductive fabric layer and a base layer on which a conductive pattern is formed. The sensor electrode according to any one of claims 1 to 4, wherein said conductive fabric layer is formed on a support. 6. The sensor electrode according to claim 5, wherein said support is made of cloth, and a thermoplastic resin layer is formed on one side thereof. 7. The sensor electrode according to claim 1, having a thickness of 1.5 mm or less. The sensor electrode according to any one of claims 1 to 7, which is formed by vacuum forming.

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