WO2016103507A1

WO2016103507A1 - Metal mesh substrate, and production method therefor

Info

Publication number: WO2016103507A1
Application number: PCT/JP2014/084675
Authority: WO
Inventors: 護日高
Original assignee: 日本テクノリード株式会社
Priority date: 2014-12-26
Filing date: 2014-12-26
Publication date: 2016-06-30

Abstract

Provided is a metal mesh substrate capable of improving the visibility of a display screen. In the metal mesh substrate, a metal mesh pattern is provided on one or both surfaces of a transparent substrate. The metal mesh pattern is formed from a stacked body obtained by sequentially stacking, on the transparent substrate, a conductive polymer layer having a maximum reflectance for wavelengths in the range of 400-700 nm of 20% or lower, and a metal layer.

Description

Metal mesh substrate and manufacturing method thereof

The present invention relates to a metal mesh substrate. The present invention also relates to a method for manufacturing a metal mesh substrate. In particular, the present invention relates to a metal mesh substrate useful as a touch panel substrate.

In recent years, the demand for display devices with a touch panel in which a touch panel (hereinafter also referred to as a “touch sensor”) is provided on the front surface of the display is in widespread use of small portable terminals typified by cellular phones, portable information terminals, car navigation systems, and the like. It grows greatly with. The touch panel is an input device that enables an operation instruction and data input by detecting the position of a part touched by a finger, a pen, or the like. As a position detection method, a resistive film method, an infrared method, an ultrasonic method, an electromagnetic induction / coupling method, and the like are known in addition to the mainstream capacitive coupling method.

Although the ITO film, which is currently the mainstream touch panel material, is suitable for small display devices, it has a relatively high sheet resistance. For this reason, it cannot be used technically for medium- and large-sized touch panels, so in order to develop and popularize a new market for medium- and large-sized touch panels, we developed a cheaper base material and a touch panel with a more stable manufacturing process. There is a need to. Therefore, a metal mesh in which a sensor pattern used for a touch panel is formed of a highly conductive material such as copper or silver instead of an ITO film has been studied.

JP 2010-95776 A (Patent Document 1) describes a technique for forming a patterned metal film on a substrate by an electroless plating method. In this publication, a base coating for forming a metal film patterned by an electroless plating method on a substrate, the base coating comprising conductive or reducing polymer fine particles, a binder, and an inorganic system A base coating material containing a filler and having a mass ratio of the conductive or reducing polymer fine particles to the binder in the range of 1:11 to 1:60 and having a viscosity of 50 cps or more is disclosed. And it discloses that the said base coating material is pattern-printed on a base material, and the metal film is chemically plated from the electroless-plating liquid to the formed coating film layer.

JP 2010-95776 A

However, when the sensor pattern for the touch panel is formed using the technique described in Patent Document 1, light reflection from the metal film is likely to occur through the bottom surface (back surface) of the transparent substrate, which deteriorates the visibility of the display screen. There is a problem of end. Therefore, an object of the present invention is to provide a metal mesh substrate that can improve the visibility of a display screen. Another object of the present invention is to provide a method for manufacturing such a metal mesh substrate.

The present inventor has intensively studied to solve the above-mentioned problems. As a result, a metal mesh substrate manufactured by forming a conductive polymer layer having a low reflectance on a transparent substrate and forming a metal layer thereon is used as a touch panel. When used, it was found that the reflected light from the metal layer is shielded by the conductive polymer layer and hardly passes through the transparent substrate, so that the visibility of the display screen is improved. Moreover, since it becomes difficult to substantially visually recognize the wiring pattern formed by the metal mesh by setting the line width of the metal mesh to 5 μm or less, the visibility of the display screen can be further improved. The present invention has been completed based on the above findings.

In one aspect, the present invention is a metal mesh substrate having a metal mesh pattern on one or both sides of a transparent substrate, and the metal mesh pattern has a maximum reflectance of 20% or less in a wavelength region of 400 to 700 nm on the transparent substrate. It is a substrate formed of a laminate in which a certain conductive polymer layer and metal layer are sequentially laminated.

In one embodiment of the substrate according to the present invention, the conductive polymer layer has a thickness of 0.1 to 1 μm.

In another embodiment of the substrate according to the present invention, the metal layer has a thickness of 0.1 to 1 μm.

In yet another embodiment of the substrate according to the present invention, the total thickness of the conductive polymer layer and the metal layer is 1.5 μm or less.

In yet another embodiment of the substrate according to the present invention, the outer surface of the metal layer is blackened.

In yet another embodiment of the substrate according to the present invention, the metal mesh pattern is formed with a line width of 5 μm or less.

In yet another embodiment of the substrate according to the present invention, the metal mesh pattern forms a sensor pattern for a touch panel.

In yet another embodiment of the substrate according to the present invention, the conductive polymer layer is black.

In yet another embodiment of the substrate according to the present invention, a black dye and / or pigment is blended in the conductive polymer layer.

In another aspect of the present invention, a step 1 of forming a conductive polymer layer having a maximum reflectance of 20% or less in a wavelength region of 400 to 700 nm on one or both surfaces of a transparent substrate;
Step 2 of forming a resist film on the conductive polymer layer;
Step 3 of patterning the resist film through exposure and development,
Step 4 of removing the conductive polymer layer exposed by patterning the resist film;
Step 5 of removing the resist film remaining on the conductive polymer layer;
Forming a metal layer on the patterned conductive polymer layer; and
Is a method for manufacturing a metal mesh substrate.

In one embodiment of the method for manufacturing a metal mesh substrate according to the present invention, the method further includes a step of blackening the outer surface of the metal plating layer.

In another embodiment of the method for producing a metal mesh substrate according to the present invention, in Step 1, a conductive polymer layer is formed on both surfaces of the transparent substrate, and in Step 2, the conductive material formed on both surfaces of the transparent substrate. A resist film is formed on each of the conductive polymer layers, and in step 3, the resist films on both sides are simultaneously exposed by a double-side exposure apparatus.

In yet another embodiment of the method for manufacturing a metal mesh substrate according to the present invention, Step 4 and Step 5 are performed in the same plasma processing apparatus.

According to the present invention, the visibility of a display screen on a touch panel using a metal mesh substrate can be improved. Since the touch panel using the metal mesh technology is easy to increase in size, it is expected to spread in the future. According to the present invention, for example, a touch panel having a diagonal length of 15 inches or more, and further a diagonal length of 50 inches. The present invention can also be applied to the touch panel described above.

An example of a manufacturing process of a metal mesh substrate is illustrated.

<1. Metal mesh substrate>
In one embodiment of the metal mesh substrate according to the present invention, the metal mesh pattern is provided on one side or both sides of the transparent substrate. In the projected capacitive touch panel that is one of the uses of the metal mesh substrate according to the present invention, two electrode layers in the x-axis direction and the y-axis direction are stacked with an insulating layer interposed therebetween, and the touch position is set between the electrodes. It is detected from the change in capacitance. Therefore, in a preferred embodiment of the metal mesh substrate according to the present invention, the metal mesh pattern is provided on both surfaces of the transparent substrate. The metal mesh pattern can be typically a sensor pattern for a touch panel. When the metal mesh is provided on both surfaces of the transparent substrate, the electrode layer in the x-axis direction and the electrode layer in the y-axis direction can be formed with the metal mesh, respectively.

The material of the transparent substrate is not limited, but glass such as soda lime glass, silicate glass, barium glass, phosphate glass, borate glass, fluoride glass and quartz glass, polyethylene terephthalate (PET), Examples thereof include polyester resins such as polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN), and resins such as cycloolefin resins, polycarbonate resins, polyimide resins, and cellulose resins. Among them, resins that can be produced as a flexible substrate and can be produced in a roll-to-roll method are preferable, and polyethylene terephthalate or cycloolefin resins are particularly preferable. The transparent resin substrate can generally be provided in the form of a film.

The thickness of the transparent substrate is not limited, but is preferably 10 μm to 700 μm, more preferably 25 μm to 200 μm. If the thickness is within the above range, the transparent substrate can have durability and moderate flexibility when made of a resin film, so that a conductive polymer layer and a metal layer are roll-to-roll on it. It is possible to form a film with high productivity by the method.

In one embodiment of the metal mesh substrate according to the present invention, the metal mesh pattern is formed of a laminate in which a conductive polymer layer having a reflectance of 20% or less and a metal layer are sequentially laminated on a transparent substrate. . By forming the conductive polymer layer on the transparent substrate, the reflected light from the metal layer is shielded by the conductive polymer layer and hardly passes through the transparent substrate, thereby improving the visibility of the display screen. The reflectance of the conductive polymer layer is preferably in the range of 20 to 1%, more preferably in the range of 10 to 1%, still more preferably in the range of 7 to 1%, and still more preferably 5%. It is in the range of ˜1%. The color of the conductive polymer layer is preferably black from the viewpoint of reducing the reflectance. In the present invention, the reflectance can be measured with a spectral reflectometer (for example, URE-50 manufactured by USHIO INC.) And refers to the maximum reflectance in visible light (wavelength 400 to 700 nm). The incident angle at the time of reflectance measurement is 30 °, and a 75 W xenon lamp is used.

Examples of the polymer material constituting the conductive polymer layer include polyaniline, polythiophene, polypyrrole, polyphenylene, polyfluorene, polybithiophene, polyisothiophene, poly (3,4-ethylenedioxythiophene), polyisothione. Examples include thianaphthene, polyisonaphthothiophene, polyacetylene, polydiacetylene, polyparaphenylene vinylene, polyacene, polythiazyl, polyethylene vinylene, polyparaphenylene, polydodecylthiophene, polyphenylene vinylene, polythienylene vinylene, polyphenylene sulfide, and their derivatives. it can.

A dopant may be used in combination for the purpose of increasing the electrical conductivity of the conductive polymer. Examples of dopants include halogens such as iodine and chlorine, Lewis acids such as BF ₃ and PF ₅ , proton acids such as nitric acid and sulfuric acid, transition metals, alkali metals, amino acids, nucleic acids, surfactants, dyes, chloranil, tetra Well-known things are illustrated, such as cyanoethylene and TCNQ.

By forming the conductive polymer layer having high conductivity on the transparent substrate, the metal layer formed by the plating process is easily and uniformly formed under a wide range of process conditions. The sheet resistance value of the conductive polymer layer is preferably 10 ⁷ Ω / □ or less, more preferably 10 ⁵ Ω / □ or less, still more preferably 10 ⁴ Ω / □ or less, such as 10 ² to 10 ⁷ Ω / □. Further, the sheet resistance value varies depending on the thickness of the conductive polymer layer, but a preferable thickness is separately described below.

If low reflectivity cannot be ensured due to the polymer itself being transparent, etc., reflect the reflectivity by blending the conductive polymer layer with the necessary amount of dark color typified by black pigments such as black pigments and black dyes. Can be controlled. The pigment and the dye are preferably water-soluble from the viewpoint of uniform dispersibility in the polymer. The color of the conductive polymer layer is preferably black from the viewpoint of reducing the reflectance, but can be used even when it is not black. For example, when the polymer itself is blue or red, it can be used depending on its color density, or it can be colored by blending a blue or red pigment or dye. For example, since polythiophene is blue, it can be used as it is. However, it is more desirable to reduce the reflectance and improve the visibility by blending a black pigment or dye.

In the conductive polymer layer, a binder can be blended in order to improve adhesion with the transparent substrate. The binder is not particularly limited. For example, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly (N-vinylcarbazole), hydrocarbon resin, ketone resin. , Phenoxy resin, polyamide, ethyl cellulose, vinyl acetate, ABS resin, urethane resin, melamine resin, acrylic resin, unsaturated polyester resin, alkyd resin, epoxy resin, silicon resin and the like.

The binder used can be used in an amount of 11 parts by mass or more per 1 part by mass of the conductive polymer, and specifically, in the range of 11 to 60 parts by mass with respect to 1 part by mass of the conductive polymer fine particles. Preferably there is. If the binder exceeds 60 parts by mass, metal plating may be difficult to deposit, and if the binder is less than 11 parts by mass, it is difficult to increase the viscosity of the paint.

Also, the conductive polymer layer can be blended with inorganic fillers such as carbon black, titanium oxide and silica particles for promoting the deposition of metal plating. The amount of the inorganic filler used is not particularly limited, but is preferably in the range of 0.1 to 1.5 parts by mass with respect to 1 part by mass of the binder. When the amount of the inorganic filler used exceeds 1.5 parts by mass with respect to 1 part by mass of the binder, peeling between the base material and the coating film layer is likely to occur, and good adhesion may be difficult to obtain. Moreover, when it becomes less than 0.1 mass part, metal plating may become difficult to precipitate.

The thickness of the conductive polymer layer is important from the viewpoints of a decrease in reflectance, simultaneous exposure on both sides, and plating properties. It is preferably 0.1 μm or more for the reason of ensuring a low reflectance, effectively suppressing the exposure influence on the opposite side photoresist during double-sided simultaneous exposure, and facilitating adhesion of the plating film. The thickness is more preferably 0.2 μm or more, and still more preferably 0.3 μm or more. Further, the thickness of the conductive polymer layer is preferably 1 μm or less, more preferably 0.7 μm or less, and 0.5 μm or less in order to maintain adhesion with the transparent substrate. Is even more preferred.

The material for forming the metal layer is not particularly limited as long as it is a metal, but copper, copper alloy, silver, silver alloy, gold, gold alloy, chromium, nickel, nickel alloy and the like having high conductivity are suitable. Copper is particularly preferred because it is relatively inexpensive and has high conductivity.

The thickness of the metal layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, and preferably 0.7 μm or more from the viewpoint of securing low sheet resistance and preventing disconnection. Even more preferred. In addition, the thickness of the metal layer is preferably 1 μm or less, more preferably 0.9 μm or less, and even more preferably 0.8 μm or less from the viewpoint of increasing production efficiency. In addition, although sheet resistance will fall if the thickness of a metal layer becomes large, 1 micrometer or less is sufficient for the thickness of a metal layer in this way for a touch-panel use.

In addition, since the total thickness of the conductive polymer layer and the metal layer is the height of the sensor wiring, if the wiring height becomes too high, there is a high possibility that the wiring will be peeled off during the process. Preferably, it is 1.3 μm or less, and more preferably 1.1 μm or less.

The outer surface of the metal layer is preferably blackened. Since the outer surface of the metal layer is black, light reflection from the metal layer is further suppressed, which is advantageous for improving the visibility of the display screen. As described above, in the present invention, since the conductive polymer layer having a low reflectance is interposed between the transparent substrate and the metal layer, the reflected light from the metal layer is shielded by the conductive polymer layer and is transparent. By making it difficult to pass through the substrate, the visibility of the display screen can be improved. However, this alone exposes the outer surface of the metal layer, and light reflection from the outer surface of the metal layer can still occur.

Therefore, the outer surface of the metal layer is blackened. Thereby, the light reflection from the outer surface of a metal layer can also be suppressed. From the viewpoint of effectively suppressing light reflection, the entire outer surface of the metal layer is preferably blackened. The blackening method is not particularly limited as long as the outer surface of the metal layer is blackened. For example, the outer surface of the metal layer (usually a copper layer) is oxidized to grow a cuprous oxide film. The surface oxidation process represented by the process to make is illustrated. In addition, it is possible to blacken by chemical conversion treatment, black chrome plating, black nickel plating, etc., but it is a process that can be incorporated on the plating process line and due to the high processing speed, blackening due to surface oxidation treatment of the thin film preferable. The blackening treatment also has a role of imparting a rust prevention function.

The line width of the metal mesh pattern is preferably 10 μm or less, more preferably 5 μm or less from the viewpoint of making the mesh pattern substantially unrecognizable by human vision and significantly improving the visibility of the display screen. Preferably, it is still more preferably 3 μm or less, still more preferably 2 μm or less, for example, about 1 to 5 μm.

The size of the metal mesh substrate is not particularly limited, and can be used for any of small, medium and large touch panels. For example, in the case of a film substrate wound on a roll, the river width of the film substrate can be 500 to 600 mm, can be 800 mm or more for a medium or larger panel, and can be 1500 mm or more for a large panel. You can also.

<2. Manufacturing method of metal mesh substrate>
A suitable method for manufacturing the metal mesh substrate according to the present invention will be described below with reference to the drawings. First, a transparent substrate 12 is prepared, and a conductive polymer layer 11 having a maximum reflectance of 20% or less is formed on one or both surfaces of the transparent substrate 12 ((1) in FIG. 1). The method for forming the conductive polymer layer 11 on the transparent substrate 12 is not limited, but a dispersion liquid in which fine particles of the conductive polymer are dispersed in an organic solvent is applied on the transparent substrate, followed by heat drying. The method of doing is mentioned. In order to avoid damage to the transparent substrate 12, the temperature at the time of heat drying is preferably 90 ° C. or lower. Further, a thin film may be formed by polymerizing a conductive polymer on the surface of the transparent substrate 12. The conductive polymer layer is usually in the form of a flat film having no pattern. As mentioned above, when the conductive polymer is not black or the blackness is insufficient, the conductive polymer layer is blended with a dark pigment such as black dye or black pigment. The reflectance may be adjusted. As the conductive polymer fine particles, commercially available fine particles may be used, or they can be produced by the production method described in JP 2010-95776 A.

Examples of organic solvents include aliphatic esters such as butyl acetate, aromatic solvents such as toluene, ketones such as methyl ethyl ketone, cyclohexanone and isophorone, cyclic saturated hydrocarbons such as cyclohexane, and chain saturated hydrocarbons such as n-octane. , Chain saturated alcohols such as methanol, ethanol, n-octanol, aromatic esters such as methyl benzoate, aliphatic ethers such as diethyl ether, and mixtures thereof. In order to maintain the dispersion stability in the dispersion, it is preferable that the conductive polymer fine particles have a solid content of 5% by mass or less (solid content ratio) of the mass of the dispersion.

The average particle diameter of the conductive polymer fine particles used can be, for example, 1 to 500 nm, typically about 10 to 100 nm. Here, the particle size is defined as the diameter of the smallest circle that can surround the fine particles to be measured.

In the dispersion, various additives such as binders, dispersion stabilizers, thickeners, inorganic fillers and dopants can be added in addition to the conductive polymer fine particles.

Next, a resist film 13 is formed on the conductive polymer layer 11 ((2) in FIG. 1). As the resist, either a liquid or solid resist can be used. Photoresists and dry film resists can be suitably used, but liquid photoresists are more preferred because of their good workability and easy application uniformly. For example, a resist film can be formed by baking after applying a liquid photoresist on the conductive polymer layer using a slit coater for photoresist. Baking is preferably performed at 100 ° C. or lower in order to avoid thermal damage to the substrate.

Next, the resist film 13 is patterned ((3) in FIG. 1). The thickness of the resist film is not limited, but can be formed with a thickness of about 0.1 to 10 μm, and typically with a thickness of about 2 to 4 μm. What is important here is that when the conductive polymer layer is removed later, the thickness of the resist film is set so that the resist film does not disappear before the conductive polymer layer. Since the resist film generally has a higher removal rate than the conductive polymer layer, it is necessary to ensure a sufficient thickness of the resist film. However, it should be noted that side etching tends to occur if the resist film is too thick. Further, the uniformity of the applied resist film is important, and it is within ± 10%, more preferably ± 5%. Examples of a method for patterning the resist film 13 include a method of transferring the pattern to the resist film by exposing the resist film through a given mask pattern with ultraviolet rays or the like. A portion indicated by reference numeral 14 in FIG. 1 is an exposed portion. For the exposure, either a contact exposure system or a non-contact exposure system (for example, a proximity exposure system in which a gap is provided between the substrate and the mask and the exposure surface is scanned or exposed in a non-contact manner) can be adopted. However, the contact exposure method is preferable because the apparatus price is low and the resolution is high, and the hard contact exposure method is more preferable. The exposure amount is determined by the respective resist characteristics in order to ensure the optimum line width and development conditions.

When manufacturing touch panels with sensor patterns formed on the upper and lower surfaces of a transparent substrate, it is necessary to expose the upper and lower surfaces with an exposure device. However, with transparent materials, the upper and lower exposure amounts affect each other and are accurate. A pattern cannot be formed. However, in the present invention, since the conductive polymer layer on the transparent substrate sufficiently shields the influence of exposure from the upper and lower surfaces, an accurate pattern can be formed on the upper and lower surfaces of the transparent substrate. Therefore, in the present invention, it is possible to simultaneously expose the upper and lower surfaces of the transparent substrate using a double-side exposure apparatus, and the production efficiency can be remarkably improved.

Next, when the exposed resist film is developed with a developer, the resist film is removed according to the pattern to expose the conductive polymer layer ((4) in FIG. 1). A portion indicated by reference numeral 15 in FIG. 1 is a portion where the conductive polymer layer is exposed. The resist film may be either a positive type or a negative type. In the case of the positive type, the exposed resist film is removed, and an unexposed resist film is left as a pattern portion. The development processing can be performed by a resist development processing apparatus.

Next, the exposed conductive polymer layer is removed by patterning the resist film ((5) in FIG. 1). A method for removing the conductive polymer layer includes, but is not limited to, wet etching and dry etching. At this time, a wet etching apparatus or a dry etching apparatus can be used. From the viewpoint of suppressing side etching and forming a highly accurate pattern, dry etching is preferable. Examples of dry etching include plasma etching, photoetching, ion beam etching, and the like. The resist film is also removed during the etching, but the resist film is removed while removing the conductive polymer layer by optimally setting the resist film thickness by determining the selection ratio of the resist and conductive polymer removal amount. Can be left behind. Thereby, since the resist film functions as a kind of mask, the exposed conductive polymer layer can be selectively removed. A portion indicated by reference numeral 16 in FIG. 1 is a portion from which the conductive polymer layer has been removed.

Next, the resist film remaining on the conductive polymer layer is removed ((6) in FIG. 1). This step can be performed, for example, by bringing a resist film into contact with a stripping solution, and a resist stripping apparatus can be used. As a contact method, a method in which the entire substrate on which the patterned resist film remains is placed in a container containing a stripping solution (immersion method), or a method in which the stripping solution is sprayed onto the resist film (spraying method, spraying method). Can be illustrated. As an even more efficient method, when dry etching is performed using a plasma processing apparatus in the previous process, a separate stripping condition is set using the plasma processing apparatus, and the resist film remaining on the conductive polymer layer is removed. The peeling method by doing can be used. In this case, it is not necessary to prepare a resist stripping apparatus separately, and the cost merit is high.

The stripping solution is generally used by heating, but the stripping solution may adversely affect the conductivity of the conductive polymer layer in high temperature treatment. Therefore, 50 degrees C or less is preferable. More preferably, it is 40 degrees C or less, More preferably, it is 35 degrees C or less, Most preferably, it is 30 degrees C or less. Moreover, since peeling ability falls at low temperature, 5 degreeC or more is preferable, More preferably, it is 10 degreeC or more.

Next, a metal layer 17 is formed on the patterned conductive polymer layer 11 ((7) in FIG. 1). The formation of the metal layer 17 is not limited, but an electroless plating method and an electroplating method can be employed and may be performed by a plating apparatus. Any known method may be used for the electroless plating method and the electroplating method. For example, in the case of the electroless plating method, the conductive polymer particles in the conductive polymer layer are dedoped and reduced. After that, the substrate having the patterned conductive polymer layer is immersed in a catalyst solution for adhering a catalytic metal such as palladium chloride, washed with water, and immersed in an electroless plating bath. A metal layer can be selectively formed on the molecular layer.

As the dedoping treatment, a reducing agent, for example, a borohydride compound such as sodium borohydride or potassium borohydride, an alkylamine borane such as dimethylamine borane, diethylamine borane, trimethylamine borane, triethylamine borane, hydrazine, etc. The method of processing and reducing with the solution to contain, or the method of processing with an alkaline solution is mentioned. It is preferable to treat with an alkaline solution from the viewpoint of operability and economy.

The catalyst solution is a solution containing a noble metal (catalyst metal) having catalytic activity for electroless plating. Examples of the catalyst metal include palladium, gold, platinum, rhodium, etc. These metals may be simple substances or compounds. A palladium compound is preferable from the viewpoint of stability including a metal, and palladium chloride is particularly preferable among them. A preferred specific catalyst solution includes 0.05% palladium chloride-0.005% hydrochloric acid aqueous solution (pH 3). The treatment temperature is 20 to 50 ° C., preferably 30 to 40 ° C., and the treatment time is 0.1 to 20 minutes, preferably 1 to 10 minutes.

After the catalyst application treatment, the substrate having the patterned conductive polymer layer is immersed in a plating solution, whereby an electroless plating film can be formed. The plating solution is not particularly limited as long as it is a plating solution usually used for electroless plating. That is, metal, copper, gold, silver, nickel, etc. that can be used for electroless plating can all be applied, but copper is preferred. Specific examples of the electroless copper plating bath include, for example, an ATS add copper IW bath (Okuno Pharmaceutical Co., Ltd.). The treatment temperature is 20 to 50 ° C., preferably 30 to 40 ° C., and the treatment time is 1 to 30 minutes, preferably 5 to 15 minutes. The obtained plated product is preferably cured for several hours or more, for example, 2 hours or more in a temperature range lower than Tg of the substrate used.

After removing the resist film, the substrate may be cleaned with a cleaning solution such as water or an organic solvent before metal plating. Further, in order to improve the adhesion of the metal layer 17 to the conductive polymer layer 11, the surface of the conductive polymer layer 11 can be cleaned before the metal layer 17 is formed. The cleaning method is not limited, and examples thereof include plasma treatment.

After forming the metal layer 17, it is preferable to further blacken the outer surface of the metal layer to form a blackened film 18 ((8) in FIG. 1). The blackening process is exemplified by the method described above. The advantages of the blackening process are also as described above. The blackening process can be performed using a blackening apparatus. The plating apparatus may have the function of a blackening apparatus.

In the above method, a metal mesh substrate is manufactured by performing metal plating at the final stage using a thin black conductive polymer. This method has an effect of reducing copper consumption by 90% or more compared to a manufacturing method in which a pattern is formed by etching a copper foil. Moreover, since the consumed conductive polymer itself is an inexpensive material compared to the copper foil, the manufacturing cost of the metal mesh substrate can be significantly reduced by the present invention.

The metal mesh substrate according to the present invention can be applied to a capacitively coupled touch panel.

Hereinafter, examples for better understanding of the present invention and its advantages will be shown, but the present invention is not limited to these examples.

(Example 1)
A substrate in which a black polypyrrole layer having a thickness of about 0.3 μm was formed on the upper and lower surfaces of a polyethylene terephthalate (PET) film having a thickness of 100 μm was prepared. In the case of a double-sided coated product having a thickness of 0.3 μm of this polypyrrole layer, an ORC UV light source (42 mW / cm ² ) is used, and an ORC U-35 / U-42 illuminance meter is used. The rate of transmission through the sensor was measured. The measured transmittance was 27%. In addition, the reflectance of the polypyrrole layer of the double-sided coated product is irradiated with light in the region of 200 nm to 800 nm, and the reflectance is measured by a spectral reflectometer (USE 50 made by USHIO, incident angle 30 °, using a 75 W xenon lamp). As a result, the maximum reflectance of the region in the visible light (400 to 700 nm) was 5.89%.

Next, polypyrrole on one surface of the defoamed positive photoresist is uniformly (coating uniformity: ± 4.8%) with a thickness of about 2.2 μm using an Able Japan slit coater (TL0704) device. It was applied to the layer (application area 370 mm × 470 mm). After coating, the photoresist film was dried with hot air / IR heater at 100 ° C. or lower for 15 minutes. Subsequently, a photoresist film was formed in the same manner on the polypyrrole layer on the other surface. The uniformity of the photoresist coating was determined by measuring the film thickness of the photoresist film at 45 points over the entire film by spectral interference using an Optical NanoGauge film thickness meter manufactured by Hamamatsu Photonics, Inc. ± (maximum film thickness-minimum film) Thickness) / (maximum film thickness + minimum film thickness) × 100 (%).

Next, a mask of a sensor pattern for touch panel (the line width of the portion where the metal layer is formed is 1, 2, 3, 5, 8, 11 μm depending on the location) is applied to both the upper and lower photoresist films (Toa Gosei). Hard contact exposure (double-sided exposure equipment manufactured by Dainippon Kaken: RA series) was performed by vacuum-adhering to a positive resist (Clearmage TPR) made by UV irradiation and exposing the photoresist to UV light from the mask to transfer the pattern. . The exposure amount was in the range of 100 mJ to 140 mJ / cm ² .

Next, using a resist developing apparatus, the exposed resist was developed to expose the polypyrrole layer. In order to perform stable development processing, temperature control (25 ° C. ± 1 ° C.) and concentration management of the chemical solution were controlled by PID parameters.

Using the patterned resist film as a mask material, the exposed polypyrrole layer is removed by plasma etching, and then the photoresist film remaining on the polypyrrole layer is stripped with an alkaline aqueous solution using a resist stripping apparatus. Only the pattern portion of the polypyrrole layer was exposed on the surface. In order to remove the remaining resist film and perform the subsequent plating process more efficiently, the polypyrrole layer after resist removal was irradiated with plasma for a short time (about 1 minute).

By performing electroless copper plating on the patterned polypyrrole layer, a copper plating layer was formed only on the polypyrrole layer, and a metal mesh substrate having a predetermined sensor pattern was obtained. Then, the blackening process which forms a cuprous oxide on the surface of a copper plating layer was performed. The thickness of the obtained copper plating layer was about 0.5 μm.

When the metal mesh substrate obtained by the above method was visually observed, the reflected light from the sensor pattern was hardly confirmed, and it was difficult to visually recognize the sensor pattern. When the sensor pattern was observed with a microscope, the metal mesh was patterned on the transparent substrate with a line width of about 1, 2, 3, 5, 8, and 11 μm with high accuracy according to the line width of the sensor pattern. The transmittance in the sensor pattern was 83 to 88%. The sheet resistance value was 1 to 20Ω / □. The transmittance was determined by measuring the ratio of visible light passing through the sensor using an ORC UV light source (42 mW / cm ² ) and using an ORC U-35 / U-42 illuminometer. . The sheet resistance is a contact-type (4-probe method) resistance measuring instrument. Four needle-shaped electrodes are placed on a measurement sample on a straight line, a constant current is passed between the two outer probes, and the inner two The resistance was determined by measuring the potential difference generated between the probe tips.

The touch panel sensors currently produced are mainly substrates using ITO film, but the ITO substrate cannot be applied to medium and large panels due to its high sheet resistance. A low sheet resistance material sensor such as a mesh sensor is required. The touch panel made using the metal mesh substrate according to the present invention has a low electric resistance because the sensor pattern is made of metal. Therefore, according to the present invention, not only a small touch panel but also a medium / large touch panel can be easily manufactured, and high visibility can be secured. For this reason, it is considered that the present invention greatly contributes to the expansion of the medium and large touch panel market, which is a new market.

DESCRIPTION OF SYMBOLS 11 Conductive polymer layer 12 Transparent substrate 13 Resist film 14 Exposure location 15 Exposed location of the conductive polymer layer 16 Location where the conductive polymer layer is removed 17 Metal layer 18 Blackening treatment film

Claims

A metal mesh substrate having a metal mesh pattern on one or both sides of the transparent substrate, the metal mesh pattern having a maximum reflectivity of 20% or less in a wavelength region of 400 to 700 nm on the transparent substrate; A substrate formed of a laminate in which metal layers are sequentially laminated.
2. The substrate according to claim 1, wherein the conductive polymer layer has a thickness of 0.1 to 1 μm.
3. The substrate according to claim 1, wherein the metal layer has a thickness of 0.1 to 1 μm.
The substrate according to any one of claims 1 to 3, wherein the total thickness of the conductive polymer layer and the metal layer is 1.5 µm or less.
The substrate according to any one of claims 1 to 4, wherein the outer surface of the metal layer is blackened.
6. The substrate according to claim 1, wherein the metal mesh pattern is formed with a line width of 5 μm or less.
The substrate according to any one of claims 1 to 6, wherein the metal mesh pattern forms a sensor pattern for a touch panel.
The substrate according to any one of claims 1 to 7, wherein the conductive polymer layer is black.
The substrate according to any one of claims 1 to 8, wherein the conductive polymer layer is mixed with a black dye and / or pigment.
Forming a conductive polymer layer having a maximum reflectance of 20% or less in a wavelength region of 400 to 700 nm on one or both surfaces of a transparent substrate;
Step 2 of forming a resist film on the conductive polymer layer;
Step 3 of patterning the resist film through exposure and development,
Step 4 of removing the conductive polymer layer exposed by patterning the resist film;
Step 5 of removing the resist film remaining on the conductive polymer layer;
Forming a metal layer on the patterned conductive polymer layer; and
A method of manufacturing a metal mesh substrate including:
The method for producing a metal mesh substrate according to claim 10, further comprising a step of blackening the outer surface of the metal plating layer.
In step 1, a conductive polymer layer is formed on both surfaces of the transparent substrate, in step 2, a resist film is formed on the conductive polymer layer formed on both surfaces of the transparent substrate. The method for producing a metal mesh substrate according to claim 10 or 11, wherein the resist film is simultaneously exposed by a double-side exposure apparatus.
The method for manufacturing a metal mesh substrate according to any one of claims 10 to 12, wherein the step 4 and the step 5 are performed in the same plasma processing apparatus.