KR20200102930A - Light transmitting conductive film - Google Patents

Abstract

The objective of the present invention is to provide a light transmitting conductive film that can have both good conductivity and etching properties. The light transmitting conductive film (1) includes a transparent substrate (2) and a light-transmitting conductive layer (5) disposed above the transparent substrate (2), wherein the ratio of n to μ (n/μ) is 4.0 or more when the thickness of the light-transmitting conductive layer (5) exceeds 40 nm, carrier density is n × 10^19 (/cm^3), and hole mobility is μ (cm^2/V·s) in the light-transmitting conductive layer (5).

Description

Light transmissive conductive film {LIGHT TRANSMITTING CONDUCTIVE FILM}

The present invention relates to a light-transmitting conductive film, specifically, to a light-transmitting conductive film preferably used for optical applications.

Conventionally, a transparent conductive film including a transparent conductive layer is used for a substrate for a touch panel in an image display device or the like. For example, Patent Document 1 discloses a transparent conductive film comprising a polymer film and a transparent conductive layer made of an indium-tin composite oxide (ITO).

In general, in order to use as a substrate for a touch panel, a transparent conductive layer is patterned by etching into a desired pattern (eg, an electrode pattern or a wiring pattern) of a touch input region.

Japanese Patent Application Publication No. 2017-71850

By the way, in a transparent conductive film, in order to reduce resistance and improve conductivity, it is considered to thicken a transparent conductive layer such as ITO. However, when the transparent conductive layer is thickened, there arises a problem that the etching time increases. That is, the etching property is inferior. As a result, the productivity of the substrate for a touch panel provided with a desired pattern is inferior.

The present invention is to provide a light-transmitting conductive film that can achieve both good conductivity and etching properties.

The present invention [1] includes a transparent substrate and a light-transmitting conductive layer disposed on one side in the thickness direction of the transparent substrate, the thickness of the light-transmitting conductive layer is more than 40 nm, and the light-transmitting conductive layer When the carrier density in is n×10 ¹⁹ (/cm 3) and the hole mobility is μ (cm 2 /V·s), the ratio of n to μ (n/μ) is 4.0 or more. And a light-transmitting conductive film.

The present invention [2] includes the light-transmitting conductive film according to [1], in which the light-transmitting conductive layer is crystalline.

The present invention [3] includes the light-transmitting conductive film described in [1] or [2], in which the light-transmitting conductive layer contains an indium-based inorganic oxide.

In the present invention [4], the light-transmitting conductive layer includes a first region in which the mass ratio of impurity inorganic element to indium is 0.05 or more, and a second region in which the mass ratio of impurity inorganic element to indium is less than 0.05, in the thickness direction. And the light-transmitting conductive film described in [3].

In the present invention [5], the carrier density of the light-transmitting conductive layer is 50 × 10 ¹⁹ (/cm 3) or more and 170 × 10 ¹⁹ (/cm 3) or less, and the hole mobility is 5 (cm 2 /V·s). ) Or more and 40 (cm 2 /V·s) or less, the light-transmitting conductive film according to any one of [1] to [4].

The present invention [6] includes the light-transmitting conductive film according to any one of [1] to [5], in which the light-transmitting conductive layer is patterned.

According to the light-transmitting conductive film of the present invention, the conductivity is good and the light-transmitting conductive layer can be etched at a good rate.

1 shows a cross-sectional view of an embodiment of the light-transmitting conductive film of the present invention.
FIG. 2 is a cross-sectional view of a patterned light-transmitting conductive film in which the light-transmitting conductive film shown in FIG. 1 is patterned.
3 shows a graph plotting the relationship between the ratio of n to μ and the etch rate.

<one embodiment>

An embodiment of the light-transmitting conductive film 1 of the present invention will be described with reference to FIGS. 1 to 2.

In Fig. 1, the vertical direction of the paper is the vertical direction (thickness direction, the first direction), the upper side of the paper is the upper side (thickness direction one side, the first direction one side), the paper lower side, the lower side (thickness direction the other side) , The other side in the first direction). In addition, the left-right direction and the depth direction of the paper are plane directions orthogonal to the vertical direction. Specifically, it is based on the direction arrows in each drawing.

1. Light-transmitting conductive film

The light-transmitting conductive film 1 has a film shape (including a sheet shape) having a predetermined thickness, extends in a predetermined direction (surface direction) orthogonal to the thickness direction, and has a flat upper surface and a flat lower surface. The light-transmitting conductive film 1 is, for example, a component such as a substrate for a touch panel provided in an image display device, and in other words, it is not an image display device. That is, the light-transmitting conductive film 1 is a component for manufacturing an image display device and the like, and does not include an image display element such as an LCD module, and includes a transparent substrate 2 and a hard coat layer 3 and optical It is a device that includes an adjustment layer 4 and a light-transmitting conductive layer 5, distributes as a component alone, and can be used industrially.

Specifically, as shown in FIG. 1, the light-transmitting conductive film 1 includes a transparent substrate 2, a hard coat layer 3 disposed on the upper surface (one side in the thickness direction) of the transparent substrate 2, and , An optical adjustment layer 4 disposed on the upper surface of the hard coat layer 3, and a light-transmitting conductive layer 5 disposed on the upper surface of the optical adjustment layer 4. More specifically, the light-transmitting conductive film 1 includes a transparent base material 2, a hard coat layer 3, an optical adjustment layer 4, and a light-transmitting conductive layer 5 in this order. . The light-transmitting conductive film (1) is preferably composed of a transparent base material (2), a hard coat layer (3), an optical adjustment layer (4), and a light-transmitting conductive layer (5). In addition, the light-transmitting conductive film 1 is a transparent conductive film.

2. Transparent substrate

The transparent substrate 2 is a transparent substrate for securing the mechanical strength of the light-transmitting conductive film 1. That is, the transparent substrate 2 supports the light-transmitting conductive layer 5 together with the hard coat layer 3 and the optical adjustment layer 4.

The transparent substrate 2 is the lowermost layer of the light-transmitting conductive film 1 and has a film shape. The transparent substrate 2 is disposed on the entire lower surface of the hard coat layer 3 so as to contact the lower surface of the hard coat layer 3.

As the transparent base material 2, a polymer film and an inorganic plate (a glass plate, etc.) are mentioned, for example, From the viewpoint of sharing transparency and flexibility, Preferably, a polymer film is mentioned.

Examples of the material of the polymer film include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, and (meth)acrylic resins such as polymethacrylate (acrylic Resins and/or methacrylic resins), for example, olefin resins such as polyethylene, polypropylene, and cycloolefin polymers, such as polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins , Polyimide resin, cellulose resin, and polystyrene resin. These polymer films can be used alone or in combination of two or more.

From the viewpoints of transparency, flexibility, mechanical strength, etc., as the transparent base material 2, preferably, a polyethylene terephthalate film and a cycloolefin polymer film are mentioned.

The total light transmittance (JIS K 7375-2008) of the transparent substrate 2 is, for example, 80% or more, preferably 85% or more.

The thickness of the transparent base material 2 is, for example, 2 µm or more, preferably 20 µm or more, from the viewpoints of mechanical strength and spot characteristics when the light-transmitting conductive film 1 is used as a film for a touch panel. And, for example, 300 µm or less, preferably 150 µm or less. The thickness of the transparent substrate 2 can be measured using, for example, a micro-gauge type thickness meter.

A separator or the like may be formed on the lower surface of the transparent substrate 2.

3. Hard coat layer

The hard coat layer 3 is a protective layer for suppressing the occurrence of scratches in the transparent substrate 2 when manufacturing the light-transmitting conductive film 1. In addition, when a plurality of light-transmitting conductive films 1 are laminated, it is a scratch-resistant layer for suppressing the occurrence of scratches on the light-transmitting conductive layer 5.

The hard coat layer 3 has a film shape. The hard coat layer 3 is disposed on the entire upper surface of the transparent substrate 2 so as to contact the upper surface of the transparent substrate 2. More specifically, the hard coat layer 3 is disposed between the transparent substrate 2 and the optical adjustment layer 4 so as to contact the upper surface of the transparent substrate 2 and the lower surface of the optical adjustment layer 4 have.

The hard coat layer 3 is formed from a hard coat composition. The hard coat composition contains a resin, and preferably consists of a resin.

Examples of the resin include a curable resin and a thermoplastic resin (eg, a polyolefin resin), and preferably, a curable resin is used.

Examples of the curable resin include active energy ray-curable resins cured by irradiation with active energy rays (specifically, ultraviolet rays, electron beams, etc.), for example, thermosetting resins cured by heating. There exist, Preferably, an active energy ray-curable resin is mentioned.

The active energy ray-curable resin includes, for example, a polymer having a functional group having a polymerizable carbon-carbon double bond in the molecule. As such a functional group, a vinyl group, a (meth)acryloyl group (methacryloyl group and/or acryloyl group), etc. are mentioned, for example.

As an active energy ray-curable resin, specifically, (meth)acrylic ultraviolet-curable resins, such as a urethane acrylate and an epoxy acrylate, are mentioned.

Further, examples of curable resins other than active energy ray-curable resins include urethane resins, melamine resins, alkyd resins, siloxane-based polymers, and thermosetting resins such as organosilane condensates.

Resins can be used alone or in combination of two or more.

The hard coat composition may contain particles. Thereby, the hard coat layer 3 can be made into an anti-blocking layer having anti-blocking properties.

Examples of the particles include inorganic particles and organic particles. Examples of the inorganic particles include silica particles, for example, metal oxide particles made of zirconium oxide, titanium oxide, zinc oxide, tin oxide, and the like, and carbonate particles such as calcium carbonate. As an organic particle, a crosslinked acrylic resin particle etc. are mentioned, for example. Particles can be used alone or in combination of two or more.

The hard coat composition may further contain known additives such as leveling agents, thixotropic agents, and antistatic agents.

The thickness of the hard coat layer 3 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and, for example, 10 μm or less, preferably 3 μm or less from the viewpoint of scratch resistance. to be. The thickness of the hard coat layer 3 can be measured by cross-sectional observation using, for example, a transmission electron microscope.

4. Optical adjustment layer

The optical adjustment layer 4 suppresses the visibility of the pattern of the light-transmitting conductive layer 5, and in order to secure the excellent transparency of the light-transmitting conductive film 1, the optical properties of the light-transmitting conductive film 1 (example For example, it is a layer to adjust the refractive index).

The optical adjustment layer 4 has a film shape. The optical adjustment layer 4 is disposed on the entire upper surface of the hard coat layer 3 so as to contact the upper surface of the hard coat layer 3. More specifically, the optical adjustment layer 4 is in contact with the upper surface of the hard coat layer 3 and the lower surface of the light transmitting conductive layer 5 between the hard coat layer 3 and the light-transmitting conductive layer 5 So, it is arranged.

The optical adjustment layer 4 is formed of an optical adjustment composition. The optical adjustment composition contains a resin, and preferably contains a resin and a particle.

Although it does not specifically limit as a resin, For example, the resin illustrated by the hard coat composition is mentioned. Preferably, a curable resin, more preferably an active energy ray curable resin, and still more preferably a (meth)acrylic ultraviolet curable resin is used.

The content ratio of the resin is, for example, 10 mass% or more, preferably 25 mass% or more, and, for example, 95 mass% or less, preferably 60 mass% or less with respect to the optical adjustment composition. to be.

As the particle, a preferable material can be selected according to the refractive index required by the optical adjustment layer, and for example, particles exemplified in the hard coat composition can be mentioned. From the viewpoint of the refractive index, preferably, inorganic particles, more preferably metal oxide particles, and still more preferably zirconium oxide particles (ZrO ₂ ) are exemplified.

The content ratio of the particles is, for example, 5 mass% or more, preferably 40 mass% or more, and, for example, 90 mass% or less, preferably 75 mass% or less with respect to the optical adjustment composition. to be.

The optical adjustment composition may further contain known additives such as a leveling agent, a thixotropic agent, and an antistatic agent.

The refractive index of the optical adjustment layer 4 is, for example, 1.40 or more, preferably 1.55 or more, and, for example, 1.80 or less, preferably 1.70 or less. The refractive index can be measured with an Abbe refractometer, for example.

The thickness of the optical adjustment layer 4 is, for example, 5 nm or more, preferably 10 nm or more, and further, for example, 200 nm or less, preferably 100 nm or less. The thickness of the optical adjustment layer 4 can be measured by cross-sectional observation using, for example, a transmission electron microscope.

5. Light-transmitting conductive layer

The light-transmitting conductive layer 5 is a transparent conductive layer for forming into a desired pattern (eg, an electrode pattern or a wiring pattern) by etching.

The light-transmitting conductive layer 5 is an uppermost layer of the light-transmitting conductive film 1 and has a film shape. The light-transmitting conductive layer 5 is disposed on the entire upper surface of the optical adjustment layer 4 so as to contact the upper surface of the optical adjustment layer 4.

Examples of the material of the light-transmitting conductive layer 5 include indium-based inorganic oxide, antimony-based inorganic oxide, and the like, preferably indium-based inorganic oxide.

The material of the light-transmitting conductive layer 5 is preferably Sn, Zn, Ga, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, Fe, Pb, Ni, Nb, Cr At least one impurity inorganic element selected from the group consisting of is contained (doped). As an impurity inorganic element, Preferably, Sn is mentioned.

As an inorganic oxide containing an impurity inorganic element, for example, in the case of an indium-based inorganic oxide, an indium tin composite oxide (ITO) is exemplified, and in the case of an antimony-based inorganic oxide, for example, an antimony tin composite Oxide (ATO) is mentioned. Preferably, ITO is mentioned.

When the light-transmitting conductive layer 5 is formed of ITO, in the whole light-transmitting conductive layer 5, the tin oxide (SnO ₂ ) content is based on the total amount of tin oxide and indium oxide (In ₂ O ₃ ). , For example, 0.5% by mass or more, preferably 3% by mass or more, and for example, 15% by mass or less, preferably 13% by mass or less.

The light-transmitting conductive layer 5 may be constituted by a single layer, or may be constituted by a plurality of layers (areas in the thickness direction). The number of layers is not limited, for example, two or more layers and five or less layers are mentioned, and preferably, two layers are used.

Preferably, the light-transmitting conductive layer 5 is composed of a plurality of layers.

Specifically, as shown by the virtual line in FIG. 1, for example, the light-transmitting conductive layer 5 is a first layer (an example of a first region) 5a and an upper side of the first layer 5a. A second layer (an example of a second region) 5b disposed in is provided.

The first layer 5a and the second layer 5b are preferably both formed of an inorganic oxide containing an impurity inorganic element, and preferably both are indium-based inorganic oxides containing an impurity inorganic element And more preferably, all of them are formed of ITO.

Further, in this case, the mass ratio of the impurity inorganic element (preferably Sn) to indium in the layer most distant from the transparent substrate 2 (i.e., the second layer 5b) is the light-transmitting conductive layer 5 Among the plurality of layers constituting the (i.e., the first layer 5a and the second layer 5b), it is preferably not the maximum, more preferably the minimum. That is, when the light-transmitting conductive layer 5 consists of the first layer 5a and the second layer 5b, the mass ratio of the impurity inorganic element to indium in the second layer 5b is the first layer 5a ) Is less than the mass ratio of impurity inorganic elements to indium.

Specifically, the first layer 5a preferably has a mass ratio of impurity inorganic elements to indium of 0.05 or more, and the second layer 5b preferably has a mass ratio of impurity inorganic elements to indium Is less than 0.05. Thereby, crystal conversion of the light-transmitting conductive layer 5 can be made possible in a short time more reliably.

More specifically, when the first layer 5a is formed of ITO, in the first layer 5a, the tin oxide (SnO ₂ ) content is the tin oxide and indium oxide (In ₂ O ₃ ). The total amount is, for example, 5% by mass or more, preferably 8% by mass or more, and further, for example, 15% by mass or less, and preferably 13% by mass or less. The content of tin oxide in the first layer 5a can improve transparency and stability of surface resistance.

When the second layer 5b is formed of ITO, in the second layer 5b, the tin oxide (SnO ₂ ) content is based on the total amount of tin oxide and indium oxide (In ₂ O ₃ ). For example, it is 0.5 mass% or more, Preferably it is 2 mass% or more, and, for example, it is less than 8 mass %, Preferably it is less than 5 mass %. When the content of tin oxide in the second layer 5b is within the above range, crystal conversion of the light-transmitting conductive layer 5 is facilitated, and the conductivity can be reliably improved.

The ratio in the thickness direction of the first layer 5a in the light-transmitting conductive layer 5 is, for example, 75% or more, preferably 80% or more, and more preferably 90% or more, Moreover, for example, it is 99% or less, Preferably it is 98% or less, More preferably, it is 97% or less. Specifically, the thickness of the first layer 5a is, for example, 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more, and, for example, 200 nm or less, Preferably, it is 150 nm or less, More preferably, it is 50 nm or less.

The ratio in the thickness direction of the second layer 5b in the light-transmitting conductive layer 5 is, for example, 25% or less, preferably 20% or less, more preferably 10% or less, For example, it is 1% or more, Preferably it is 2% or more, More preferably, it is 3% or more. Further, specifically, the thickness of the second layer 5b is, for example, 1 nm or more, preferably 1.5 nm or more, more preferably 2 nm or more, and, for example, 40 nm Hereinafter, preferably, it is 20 nm or less, More preferably, it is 10 nm or less.

The total thickness of the light-transmitting conductive layer 5 exceeds 40 nm, preferably 42 nm or more, and more preferably 50 nm or more. The upper limit of the total thickness is not limited, and is, for example, 300 nm or less, preferably 180 nm or less, and more preferably 100 nm or less. When the total thickness of the light-transmitting conductive layer 5 is more than the above lower limit, the conductivity of the light-transmitting conductive layer 5 is good.

The thickness of the light-transmitting conductive layer 5 can be measured by cross-sectional observation using, for example, a transmission electron microscope.

The light-transmitting conductive layer 5 may be crystalline or amorphous, but is preferably crystalline from the viewpoint of good conductivity and etching properties.

Whether the light-transmitting conductive layer is amorphous or crystalline, for example, when the light-transmitting conductive layer is an ITO layer, is immersed in hydrochloric acid at 20°C (concentration 5% by mass) for 15 minutes, washed with water and dried, and then about 15 mm It can be determined by measuring the resistance between the terminals between. In this specification, after immersion, washing and drying in hydrochloric acid (20°C, concentration: 5% by mass), when the resistance between terminals between 15 mm exceeds 10 kΩ, the ITO layer is said to be amorphous, and between 15 mm When the resistance between terminals of is less than 10 kΩ, the ITO layer is said to be crystalline.

6. Manufacturing method of light-transmitting conductive film

Next, the method of manufacturing the light-transmitting conductive film 1 is described. In order to manufacture the light-transmitting conductive film 1, for example, on the upper surface (thickness direction one side) of the transparent substrate 2, the hard coat layer 3, the optical adjustment layer 4, and the light-transmitting conductive layer 5 ) Is formed in this order. It will be described in detail below.

First, a known or commercially available transparent substrate 2 is prepared.

After that, if necessary, from the viewpoint of adhesion between the transparent substrate 2 and the hard coat layer 3, the transparent substrate 2 is, for example, sputtered, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion. , Etching treatment, such as oxidation, and primer treatment can be performed. In addition, the transparent substrate 2 can be dust-removed and cleaned by solvent cleaning or ultrasonic cleaning.

Next, the hard coat layer 3 is formed on the upper surface of the transparent substrate 2. For example, the hard coat layer 3 is formed on the upper surface of the transparent base material 2 by wet-coating the hard coat composition on the upper surface of the transparent base material 2.

Specifically, for example, a solution (varnish) obtained by diluting the hard coat composition with a solvent is prepared, and then, the hard coat composition solution is applied to the upper surface of the transparent substrate 2 and dried.

As a solvent, an organic solvent, an aqueous solvent (specifically, water), etc. are mentioned, for example, Preferably, an organic solvent is mentioned. Examples of the organic solvent include alcohol compounds such as methanol, ethanol, and isopropyl alcohol, such as ketone compounds such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, such as ethyl acetate and butyl acetate. And ether compounds such as propylene glycol monomethyl ether, and aromatic compounds such as toluene and xylene. These solvents can be used alone or in combination of two or more.

The solid content concentration in the hard coat composition solution is, for example, 1 mass% or more, preferably 10 mass% or more, and, for example, 30 mass% or less, preferably 20 mass% or less. .

The application method can be appropriately selected depending on the hard coat composition solution and the transparent substrate (2). Examples of the coating method include a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, and an extrusion coating method.

The drying temperature is, for example, 50°C or more, preferably 70°C or more, and for example, 200°C or less, preferably 100°C or less.

The drying time is, for example, 0.5 minutes or more, preferably 1 minute or more, and for example, 60 minutes or less, preferably 20 minutes or less.

Thereafter, when the hard coat composition contains an active energy ray-curable resin, the active energy ray-curable resin is cured by irradiating an active energy ray after drying the hard coat composition solution.

In addition, when the hard coat composition contains a thermosetting resin, the thermosetting resin can be thermosetted together with drying of the solvent by this drying step.

Next, the optical adjustment layer 4 is formed on the upper surface of the hard coat layer 3. For example, the optical adjustment layer 4 is formed on the upper surface of the hard coat layer 3 by wet-coating the optical adjustment composition on the upper surface of the hard coat layer 3.

Specifically, for example, a solution (varnish) obtained by diluting the optical adjustment composition with a solvent is prepared, and subsequently, the optical adjustment composition solution is applied to the upper surface of the hard coat layer 3 and dried.

Conditions such as preparation, application, and drying of the optical adjustment composition can be the same as the conditions such as preparation, application, and drying exemplified in the hard coat composition.

In addition, when the optical adjustment composition contains an active energy ray-curable resin, the active energy ray-curable resin is cured by irradiating an active energy ray after drying the optical adjustment composition solution.

Moreover, when the optical adjustment composition contains a thermosetting resin, by this drying process, the thermosetting resin can be thermosetted together with drying of a solvent.

Next, a light-transmitting conductive layer 5 is formed on the upper surface of the optical adjustment layer 4. For example, the light-transmitting conductive layer 5 is formed on the upper surface of the optical adjustment layer 4 by a dry method.

As a dry method, a vacuum vapor deposition method, a sputtering method, an ion plating method, etc. are mentioned, for example. Preferably, a sputtering method is used. By this method, the light-transmitting conductive layer 5 of a thin film can be formed.

As a sputtering method, a dipole sputtering method, an ECR (electron cyclotron resonance) sputtering method, a magnetron sputtering method, an ion beam sputtering method, etc. are mentioned, for example. Preferably, a magnetron sputtering method is used.

The power source used in the sputtering method may be, for example, a direct current (DC) power source, an alternating current medium frequency (AC/MF) power source, a high frequency (RF) power source, and a high frequency power source in which a DC power source is superimposed.

In the case of employing the sputtering method, the above-described inorganic material constituting the light-transmitting conductive layer 5 is exemplified as a target material, and ITO is preferably used. The tin oxide concentration of ITO is, for example, 0.5% by mass or more, preferably 3% by mass or more, and, for example, 15% by mass or less, preferably from the viewpoint of durability and crystallization of the ITO layer. Is 13 mass% or less.

As the sputtering gas, an inert gas, such as Ar, is mentioned, for example. Further, preferably, a reactive gas such as oxygen gas is used in combination. In the case of using a reactive gas together, the flow rate ratio of the reactive gas to the inert gas is, for example, 0.0010 or more and 0.0100 or less.

The sputtering method is carried out under vacuum. Specifically, the pressure at the time of sputtering is, for example, 1 Pa or less, preferably 0.7 Pa or less, and, for example, 0.1 Pa or more, from the viewpoint of suppression of a decrease in sputtering rate and discharge stability. .

The partial pressure of water is, for example, 10 × 10 ^-4 Pa or less, preferably 5 × 10 ^-4 Pa or less, from the viewpoint of improving the speed of crystal conversion.

Further, in order to form the desired light-transmitting conductive layer 5, sputtering may be performed a plurality of times by appropriately setting a target material, sputtering conditions, and the like.

In particular, in the present invention, for example, by using a substrate containing a cycloolefin resin as a transparent substrate, the amount of oxygen introduced is adjusted, and a plurality of layers (preferably, the first layer 5a and the first layer By forming the light-transmitting conductive layer 5 with two layers (5b)), the light-transmitting conductive film 1 provided with the desired light-transmitting conductive layer 5 can be preferably produced.

Specifically, taking as an example the case of forming the ITO layer as the light-transmitting conductive layer 5 by sputtering, the ITO layer obtained by the sputtering method is generally formed as an amorphous ITO layer. Then, by reducing the amount of oxygen in the film forming atmosphere and generating oxygen vacancies in the ITO layer, an ITO layer capable of crystal conversion by heating is obtained. At this time, the amount of oxygen is slightly insufficient so that the ITO layer can be determined. Further, by using a cycloolefin-based resin for the transparent substrate 2, the generation of moisture that inhibits crystal conversion is reduced as compared to a polyethylene terephthalate-based resin. In addition, by configuring the light-transmitting conductive layer 5 with a plurality of layers (for example, the first layer 5a and the second layer 5b), a layer that is easy to crystallize to the exposed surface (topmost surface) (second Layer (5b)) is formed. Thereby, it is possible to form the light-transmitting conductive layer 5 capable of crystal conversion at a low temperature and in a short time.

More specifically, for example, using a cycloolefin-based film as the transparent substrate (2), the horizontal magnetic field strength is 50 mT or more and 200 mT or less (preferably, 80 mT or more, 120 mT or less). When the magnetic field strength is used and a DC power supply is used, it is as follows. In the formation of the first layer 5a, an ITO target having a high tin oxide concentration is used, and the flow rate ratio of oxygen gas to Ar gas (O ₂ /Ar) is, for example, 0.0050 or more, 0.0120 or less, preferably Specifically, it is set to 0.0070 or more and 0.0090 or less, and the flow rate ratio "(O ₂ /Ar)/(ITO thickness)" to the ITO thickness (nm) is set to, for example, 0.00010 or more and 0.00020 or less.

In addition, whether or not oxygen is introduced at a suitable ratio (slightly insufficient amount of oxygen) under the ITO film formation environment is, for example, the oxygen supply amount (sccm) (X axis) and the surface resistance of ITO obtained by the oxygen supply amount ( Ω/□) (Y axis) can be plotted on a graph and judged from the graph. That is, since the very near region (bottom region) of the graph has the smallest surface resistance and ITO has a stoichiometric composition, the value of the X axis slightly closer to the origin side than the very near region is in the present invention. It can be judged that it is an oxygen supply amount suitable for producing the light-transmitting conductive layer 5.

Thereby, the light-transmitting conductive film 1 provided with the transparent base material 2, the hard coat layer 3, the optical adjustment layer 4, and the light-transmitting conductive layer 5 in this order in the thickness direction is obtained.

Moreover, in the said manufacturing method, while conveying the transparent base material 2 by a roll-to-roll system, the hard coat layer 3, the optical adjustment layer 4, and the light-transmitting conductive layer 5 to the transparent base material 2 ) May be formed, and some or all of these layers may be formed by a batch method (single leaf method). From the viewpoint of productivity, preferably, each layer is formed on the transparent substrate 2 while conveying the transparent substrate 2 in a roll-to-roll system.

If necessary, the light-transmitting conductive film 1 can be heated. Thereby, the light-transmitting conductive layer 5 is crystallized, becomes crystalline, and the conductivity is further improved.

Specifically, heat treatment is performed on the light-transmitting conductive film 1 in the atmosphere.

The heat treatment can be performed using, for example, an infrared heater or an oven.

The heating temperature is, for example, 100°C or higher, preferably 120°C or higher, and further, for example, 200°C or lower, preferably 150°C or lower.

The heating time is appropriately determined depending on the heating temperature, but is, for example, 5 minutes or more, preferably 10 minutes or more, and further, for example, 120 minutes or less, preferably 100 minutes or less.

The light-transmitting conductive film 1 obtained in this way has the following characteristics.

The carrier density (Xa × 10 ¹⁹ /cm 3) in the light-transmitting conductive layer 5 is, for example, 50 × 10 ¹⁹ /cm 3 or more, preferably, 100 × 10 ¹⁹ /cm 3 or more, more preferably , 130 × 10 ¹⁹ /cm 3 or more, and, for example, 170 × 10 ¹⁹ /cm 3 or less, preferably 150 × 10 ¹⁹ /cm 3 or less.

The hole mobility (Ya cm 2 /V·s) in the light-transmitting conductive layer 5 is, for example, 5 cm 2 /V·s or more, preferably 10 cm 2 /V·s or more, more preferably Is 20 cm2/V·s or more, and, for example, 40 cm2/V·s or less, preferably 30 cm2/V·s or less, more preferably 23 cm2/V·s or less .

In addition, when the carrier density is n×10 ¹⁹ (/cm 3) and the hole mobility is μ (cm 2 /V·s), the ratio of n to μ (n/μ) is 4.0 or more, Preferably, it is 5.1 or more, more preferably, it is 5.5 or more, and still more preferably, it is 6.0 or more. The upper limit is not limited, and is, for example, 20.0 or less, preferably 10.0 or less. When the ratio (n/μ) is more than the above lower limit, the light-transmitting conductive layer 5 can be etched in a desired pattern in a short time, and productivity is excellent.

The surface resistance of the light-transmitting conductive layer 5 is, for example, 60 Ω/□ or less, preferably 55 Ω/□ or less, and, for example, 1 Ω/□ or more, preferably 10 It is more than Ω/□. Surface resistance can be measured by a four-terminal method.

The total light transmittance (JIS K 7375-2008) of the light-transmitting conductive film 1 is, for example, 80% or more, and preferably 85% or more.

The thickness of the light-transmitting conductive film 1 is, for example, 2 µm or more, preferably 10 µm or more, and further, for example, 100 µm or less, preferably 50 µm or less.

The light-transmitting conductive film 1 is provided in an optical device, for example. As an optical device, an image display device, a dimming device, etc. are mentioned, for example, Preferably, an image display device is mentioned. When the light-transmitting conductive film 1 is provided in an image display device (specifically, an image display device having an image display element such as an LCD module), the light-transmitting conductive film 1 is, for example, a touch panel It is used as a base material. As the form of the touch panel, various methods such as an optical method, an ultrasonic method, a capacitive method, and a resistive film method may be mentioned, and in particular, it is preferably used for a capacitive touch panel.

And this light-transmitting conductive film 1, in the light-transmitting conductive layer 5, has a thickness exceeding 40 nm, and a ratio of n to μ (n/μ) exceeds 4.0. The electroconductivity and the etching property of the light-transmitting conductive layer 5 can be compatible. That is, the light-transmitting conductive layer 5 can be patterned in a short time while the light-transmitting conductive layer 5 has good conductivity. Therefore, for example, the productivity of the patterned light-transmitting conductive film 1 having good conductivity is excellent.

For patterning of the light-transmitting conductive film 1, known etching can be employed. As the etching method, either wet etching or dry etching may be used, but from the viewpoint of production efficiency, wet etching is mentioned.

In wet etching, for example, a covering portion (masking tape, etc.) is disposed on the light-transmitting conductive layer 5 so as to correspond to the pattern portion and the non-pattern portion, and the light-transmitting conductive layer 5 exposed from the covering portion (Non-pattern part) is etched using an etching solution.

Examples of the etching solution include acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, and mixed acids thereof. After that, the covering portion is removed from the upper surface of the crystalline light-transmitting conductive layer 6, for example, by peeling or the like.

The pattern of the light-transmitting conductive layer 5 is appropriately determined depending on the application to which the light-transmitting conductive film 1 is applied, and examples thereof include an electrode pattern or wiring pattern having a stripe shape.

Thereby, the patterned light-transmitting conductive film 1A in which the light-transmitting conductive layer 5 is patterned is mentioned.

<modification example>

In the above-described embodiment, the light-transmitting conductive film (1) is provided with a transparent base material (2), a hard coat layer (3), an optical adjustment layer (4) and a light-transmitting conductive layer (5). The conductive film 1 may further include layers other than these.

For example, in one embodiment, the lower surface of the transparent substrate 2 is exposed. For example, the light-transmitting conductive film 1 has other functions such as an anti-blocking layer on the lower surface of the transparent substrate 2 You may further include a layer.

In addition, the light-transmitting conductive film (1) of one embodiment is provided with a transparent base material (2), a hard coat layer (3), an optical adjustment layer (4), and a light-transmitting conductive layer (5), for example , At least one of the hard coat layer 3 and the optical adjustment layer 4 may not be provided. Preferably, a hard coat layer 3 and an optical adjustment layer 4 are provided from the viewpoints of scratch resistance and suppression of visibility of patterns in the light-transmitting conductive layer 5.

Example

Examples and comparative examples are shown below to describe the present invention in more detail. In addition, the present invention is not limited to Examples and Comparative Examples at all. In addition, specific values such as the blending ratio (content), physical property values, and parameters used in the following description are described in the above ``Forms for carrying out the invention'', and the corresponding blending ratios (containing Ratio), physical property values, parameters, etc., can be replaced with the upper limit (a value defined as ``less than'' or ``less than'') or a lower limit (a value defined as ``above'' or ``exceeding'').

(Example 1)

As a transparent substrate, a cycloolefin polymer (COP) film (manufactured by Xeon Corporation, brand name "Zeonoa", thickness 40 µm) was prepared. On the upper surface of the transparent substrate, an ultraviolet curable resin composition made of an acrylic resin was applied, and ultraviolet rays were irradiated to form a hard coat layer (thickness of 1 μm). Subsequently, an ultraviolet curable composition containing zirconia particles was applied to the upper surface of the hard coat layer and irradiated with ultraviolet rays to form an optical adjustment layer (thickness of 90 nm, refractive index of 1.62). Thereby, a layered product including a transparent base material, a hard coat layer, and an optical adjustment layer was obtained.

A first layer (thickness of 43 nm) made of an indium tin composite oxide (ITO) layer was formed on the upper surface of the optical adjustment layer of the laminate using a vacuum sputtering device. Specifically, the inside of the vacuum sputtering apparatus is evacuated until the partial pressure of water becomes 2.0 × 10 ^-4 Pa or less, and thereafter, a mixed gas of argon gas and oxygen (flow ratio: O ₂ /Ar = 0.00763, (O ₂ /Ar)/ITO thickness ratio: 0.000178) was introduced, and a DC magnetron sputtering method was performed on the laminate in an atmosphere of a pressure of 0.4 Pa. As a target, a sintered compact of 10% by mass of tin oxide/90% by mass of indium oxide was used. In addition, the horizontal magnetic field of the target surface was set to 100 mT.

Subsequently, the target was changed to a sintered body of 3% by mass of tin oxide/97% by mass of indium oxide, and the flow rate ratio of the mixed gas of argon gas and oxygen was set to O ₂ /Ar = 0.00160. Sputtering was further performed to form a second layer (thickness 2 nm) on the upper surface of the first layer. Thereby, a light-transmitting conductive layer (transparent conductive layer) having a total thickness of 45 nm was formed on the upper surface of the optical adjustment layer.

Subsequently, it heated for 90 minutes in a 130 degreeC hot air oven, and the light-transmitting conductive layer was crystallized.

In this way, the light-transmitting conductive film (transparent conductive film) of Example 1 was produced.

(Examples 2 to 5 and Comparative Examples 1 to 3)

In the formation of the first layer and the second layer, a light-transmitting conductive film was produced in the same manner as in Example 1, except that the thickness of each layer and the flow rate ratio of gas were changed as shown in Table 1.

(1) Measurement of thickness

The thickness of the hard coat layer, the optical adjustment layer, the first layer, and the second layer was measured by cross-sectional observation using a transmission electron microscope (manufactured by Hitachi Corporation, "H-7650").

The thickness of the transparent substrate was measured using a film thickness meter (manufactured by Peacock, "Digital Dial Gauge DG-205").

(2) Measurement of carrier density and hole mobility

Using a Hall effect measuring system (manufactured by BioRad, "HL5500PC"), the hole mobility (μcm2/V·s) of the light-transmitting conductive layer was measured. The carrier density (n×10 ¹⁹ /cm 3) was calculated using the total thickness of the light-transmitting conductive layer.

(3) Evaluation of etching time

The light-transmitting conductive films of Examples and Comparative Examples were immersed in hydrochloric acid at a concentration of 7 wt% and 35° C. for a predetermined period of time (15 second intervals), followed by washing and drying, and each time, the resistance between terminals between 15 mm was increased. It was measured using a tester. At this time, the time when the resistance between terminals exceeded 50 kΩ or the insulation (error, etc.) was indicated was taken as the etching completion time. The time obtained by dividing the etching time by the value of the light-transmitting conductive layer (the value of the thickness) was calculated as the etching rate per 1 nm thickness.

The case where the etching rate is 20.0 sec/nm or less is evaluated as ◎, the case where the etching rate is more than 20.0 sec/nm and 25.0 sec/nm or less is evaluated as ○, and the etching rate exceeds 25.0 sec/nm and 31.0 sec/ The case of nm or less was evaluated as Δ, and the case where the etching rate exceeded 31.0 seconds was evaluated as x. Table 1 shows the results.

(4) surface resistance

The surface resistance of the light-transmitting conductive film of each Example and each comparative example was measured by the four-terminal method. If the surface resistance is 40 Ω/□ or less, evaluate as ◎, if the surface resistance exceeds 40 Ω/□ and 60 Ω/□ or less, evaluate as ○, and if the surface resistance exceeds 60 Ω/□ It evaluated as x. Table 1 shows the results.

In addition, from each Example and each comparative example, the ratio of n to μ (n/μ) was plotted on the horizontal axis, and the etching rate was plotted on the vertical axis, and their relational expressions were shown in graphs. This graph is shown in FIG. 3.

One ; Light transmissive conductive film
2 ; Transparent substrate
5; Light-transmitting conductive layer
5a; First floor
5b; Second floor

Claims (10)

A transparent substrate and a light-transmitting conductive layer disposed on one side in the thickness direction of the transparent substrate,
The thickness of the light-transmitting conductive layer exceeds 40 nm,
When the carrier density in the light-transmitting conductive layer is n×10 ¹⁹ (/cm 3) and the hole mobility is μ (cm 2 /V·s),
The light-transmitting conductive film, characterized in that the ratio of n to μ (n/μ) is 4.0 or more. The method of claim 1,
The light-transmitting conductive film, wherein the light-transmitting conductive layer is crystalline. The method of claim 1,
The light-transmitting conductive film, wherein the light-transmitting conductive layer contains an indium-based inorganic oxide. The method of claim 2,
The light-transmitting conductive film, wherein the light-transmitting conductive layer contains an indium-based inorganic oxide. The method of claim 3,
Wherein the light-transmitting conductive layer has a first region in which a mass ratio of impurity inorganic elements to indium is 0.05 or more, and a second region in which a mass ratio of impurity inorganic elements to indium is less than 0.05, in a thickness direction, Conductive film. The method of claim 4,
Wherein the light-transmitting conductive layer has a first region in which a mass ratio of impurity inorganic elements to indium is 0.05 or more, and a second region in which a mass ratio of impurity inorganic elements to indium is less than 0.05, in a thickness direction, Conductive film. The method of claim 1,
The carrier density of the light-transmitting conductive layer is 50 × 10 ¹⁹ (/cm 3) or more and 170 × 10 ¹⁹ (/cm 3) or less,
The light-transmitting conductive film, characterized in that the hole mobility is 5 (cm 2 /V·s) or more and 40 (cm 2 /V·s) or less. The method of claim 2,
The carrier density of the light-transmitting conductive layer is 50 × 10 ¹⁹ (/cm 3) or more and 170 × 10 ¹⁹ (/cm 3) or less,
The light-transmitting conductive film, characterized in that the hole mobility is 5 (cm 2 /V·s) or more and 40 (cm 2 /V·s) or less. The method of claim 3,
The carrier density of the light-transmitting conductive layer is 50 × 10 ¹⁹ (/cm 3) or more and 170 × 10 ¹⁹ (/cm 3) or less,
The light-transmitting conductive film, characterized in that the hole mobility is 5 (cm 2 /V·s) or more and 40 (cm 2 /V·s) or less. The method according to any one of claims 1 to 9,
The light-transmitting conductive film, characterized in that the light-transmitting conductive layer is patterned.

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