KR20200102932A - Light transmitting conductive film - Google Patents

Abstract

Provided is a light transmission type conductive film, which has good crystallization speeds and conservative properties when heated. The light transmission type conductive film (1) comprises: a transparent basic material (2); and an amorphous light transmission type conductive layer (5) arranged on an upper side of the transparent basic layer (2), wherein the amorphous light transmission type conductive layer (5) can be converted into a crystalline structure. A thickness of the amorphous light transmission type conductive layer (5) exceeds 40 nm and a carrier density in the amorphous light transmission type conductive layer (5) is 40 × 10^19 /cm^3 or more.

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 including a polymer film and a transparent conductive layer made of indium tin composite oxide (ITO).

In such a transparent conductive film, in general, by heating amorphous ITO to crystallize, the conductivity (low resistance) of the transparent conductive layer is improved.

Japanese Unexamined Patent Publication No. 2012-134085

However, in the transparent conductive film of Patent Document 1, the crystallization rate of the transparent conductive layer is insufficient, and further improvement of the speed is required. That is, it is required to crystallize a transparent conductive film in a short time.

On the other hand, if the rate of crystallization during heating is improved, crystallization becomes easy even under low temperature conditions such as room temperature. That is, it crystallizes unintentionally before crystallization (before product shipment), temporarily, when stored in a warehouse, for example. In this case, since the transparent conductive layer is partially crystallized, a problem arises in that in the crystallization step by subsequent heating, deformation occurs at the boundary between the crystallized portion and the amorphous portion generated during storage, and cracks occur. In other words, it is inferior in preservation.

The present invention is to provide a light-transmitting conductive film with good crystallization rate during heating and good storage properties.

The present invention [1] includes a transparent substrate and an amorphous light-transmitting conductive layer disposed on one side in the thickness direction of the transparent substrate, and the amorphous light-transmitting conductive layer is capable of conversion into a crystalline substance, and the amorphous light It contains a light-transmitting conductive film in which the thickness of the transparent conductive layer exceeds 40 nm and the carrier density in the amorphous light-transmitting conductive layer is 40 × 10 ¹⁹ /cm 3 or more.

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

The present invention [3] includes the light-transmitting conductive film according to [1] or [2], wherein the amorphous light-transmitting conductive layer is an indium-based inorganic oxide layer containing indium and at least one impurity inorganic element. .

According to the light-transmitting conductive film of the present invention, the crystallization rate at the time of heating and storage properties are good. Therefore, even after storing the light-transmitting conductive film of the present invention for a certain period of time, the light-transmitting conductive film can be crystallized in a short time while suppressing the occurrence of cracks.

1 shows a cross-sectional view of an embodiment of the light-transmitting conductive film of the present invention.
2 is a cross-sectional view of a crystalline light-transmitting conductive film obtained by crystallizing the light-transmitting conductive film shown in FIG. 1.

<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 an amorphous light-transmitting conductive layer 5, and 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 an amorphous light-transmitting conductive layer 5 disposed on the upper surface of the optical adjustment layer 4. More specifically, 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 an amorphous light-transmitting conductive layer (5) in this order. do. 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 an amorphous 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 amorphous 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.

As the material of the polymer film, for example, polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, for example, (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 amorphous 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 amorphous light-transmitting conductive layer 5, and in order to secure excellent transparency to the light-transmitting conductive film 1, the optical properties of the light-transmitting conductive film 1 ( For example, it is a layer which adjusts 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 between the hard coat layer 3 and the amorphous light-transmitting conductive layer 5, the upper surface of the hard coat layer 3 and the lower surface of the amorphous light-transmitting conductive layer 5 Is arranged to contact

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 amorphous 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 amorphous light-transmitting conductive layer 5 is an uppermost layer of the light-transmitting conductive film 1 and has a film shape. The amorphous 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.

As the material of the amorphous light-transmitting conductive layer 5, for example, an indium-based inorganic oxide, an antimony-based inorganic oxide, and the like, and preferably an indium-based inorganic oxide.

The material of the amorphous light-transmitting conductive layer 5 is preferably Sn, Zn, Ga, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, Fe, Pb, Ni, Nb, At least one impurity inorganic element selected from the group consisting of Cr 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) may be mentioned, and for example, in the case of an antimony-based inorganic oxide, an antimony tin composite Oxide (ATO) is mentioned. Preferably, ITO is mentioned.

When the amorphous light-transmitting conductive layer 5 is formed of ITO, in the entire amorphous light-transmitting conductive layer 5, the tin oxide (SnO ₂ ) content is the total amount of tin oxide and indium oxide (In ₂ O ₃ ). With respect to, for example, it is 0.5 mass% or more, preferably 3 mass% or more, and further, for example, it is 15 mass% or less, Preferably it is 13 mass% or less.

The amorphous light-transmitting conductive layer 5 may be composed of a single layer, or may be composed of 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.

When the amorphous light-transmitting conductive layer 5 is composed of a plurality of layers, preferably, as the imaginary line in Fig. 1 indicates, the amorphous light-transmitting conductive layer 5 is a first layer (first region ) (5a) and a second layer (second region) 5b disposed above the first layer 5a.

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 amorphous light-transmitting conductive layer 5 ) Of the plurality of layers (that is, the first layer 5a and the second layer 5b), which is preferably not the maximum, and more preferably the minimum. That is, when the amorphous light-transmitting conductive layer 5 is composed 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, crystallization of the amorphous 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, crystallization of the amorphous 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 amorphous light transmitting conductive layer 5 is, for example, 75% or more, preferably 80% or more, more preferably 90% or more. And, 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 amorphous light transmitting conductive layer 5 is, for example, 25% or less, preferably 20% or less, more preferably 10% or less. , For example, 1% or more, preferably 2% or more, and more preferably 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 amorphous light-transmitting conductive layer 5 exceeds 40 nm, and is, for example, 300 nm or less. From the viewpoint of the crystallization rate and resistance value at the time of heating, it is preferably 41 nm or more, more preferably 45 nm or more, still more preferably, more than 50 nm, particularly preferably 60 nm or more, and Preferably, it is 250 nm or less, More preferably, it is 200 nm or less, More preferably, it is 160 nm or less, Especially preferably, it is 90 nm or less. In addition, from the viewpoint of suppression of crystallization during storage and conductivity after heating, preferably, they are 100 nm or more and 180 nm or less.

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

The amorphous light-transmitting conductive layer 5 is amorphous and can be converted into crystalline (crystallization). The conversion to the crystalline material is performed by heating described later.

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 (concentration 5% by mass) at 20° C. 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

The method of manufacturing the light-transmitting conductive film 1 will be 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 amorphous 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, an amorphous light-transmitting conductive layer 5 is formed on the upper surface of the optical adjustment layer 4. For example, an amorphous 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, a thin amorphous light-transmitting conductive layer 5 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 amorphous light-transmitting conductive layer 5 is mentioned 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 rate of crystallization.

Further, in order to form the desired amorphous 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 adjusting the amount of oxygen introduced and the thickness of the amorphous light-transmitting conductive layer 5 to form an amorphous light-transmitting conductive layer 5 having a thickness exceeding 40 nm, the desired amorphous light transmittance The light-transmitting conductive film 1 provided with the conductive layer 5 can be preferably produced.

Specifically, taking as an example the case of forming the ITO layer as the amorphous 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 crystallization by heating is obtained. At this time, the amount of oxygen is slightly insufficient so that the ITO layer can be determined.

More specifically, for example, when the horizontal magnetic field strength is set to a high magnetic field strength of 50 mT or more and 200 mT or less (preferably 80 mT or more, 120 mT or less), and a DC power supply is employed, the following same. 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 0.0060 or more and 0.0080 or less, and the flow rate ratio "(O ₂ /Ar)/(ITO thickness)" to the ITO thickness (nm) is set to, for example, 0.00003 or more and 0.00020 or less, In the case of forming the second layer 5b as necessary, the flow rate ratio is appropriately set in the same manner.

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 amorphous 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 amorphous 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 amorphous light-transmitting conductive layer ( 5) 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.

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

The carrier density in the amorphous light-transmitting conductive layer 5 is 40 × 10 ¹⁹ /cm 3 or more, preferably 42 × 10 ¹⁹ /cm 3 or more, more preferably 52 × 10 ¹⁹ /cm 3 or more, and , For example, 170×10 ¹⁹ /cm 3 or less, preferably 100×10 ¹⁹ /cm 3 or less. If the carrier density is more than the above lower limit, it is possible to improve the crystallization rate during heating while suppressing crystallization during storage.

The hole mobility in the amorphous 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 20 cm 2 /V·s. s or more, and, for example, 40 cm 2 /V·s or less, preferably 30 cm 2 /V·s or less.

The specific resistance of the amorphous light-transmitting conductive layer 5 is, for example, 10 × 10 ^-4 Ω·cm or less, preferably 5 × 10 ^-4 Ω·cm or less, and, for example, 0.1 × 10 ^It is more than ^-4 Ω·cm. When the specific resistance is less than or equal to the above upper limit, the resistance value is small and the conductivity is excellent. The specific resistance can be measured by the 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.

In particular, when using the light-transmitting conductive film 1 for a substrate for a touch panel, heat treatment is preferably performed with respect to the light-transmitting conductive film 1.

In the heat treatment, for example, the light-transmitting conductive film 1 is heated 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, for example, 60 minutes or less, preferably 30 minutes or less.

Thereby, the amorphous light-transmitting conductive layer 5 is crystallized, and the crystalline light-transmitting conductive layer 6 with improved conductivity is formed. That is, as shown in Fig. 2, a crystalline light-transmitting conductive layer comprising a transparent substrate 2, a hard coat layer 3, an optical adjustment layer 4, and a crystalline light-transmitting conductive layer 6 in this order in the thickness direction. The film 7 is obtained.

The surface resistance of the crystalline light-transmitting conductive layer 6 is, for example, 60 Ω/□ or less, preferably 40 Ω/□ or less, and, for example, 1 Ω/□ or more. Surface resistance can be measured by a four-terminal method. Thereby, it is excellent in electroconductivity.

Further, if necessary, patterning treatment may be performed on the light-transmitting conductive film 1 (or the crystalline light-transmitting conductive film 7).

In the patterning treatment, a known etching method 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.

The shape of the pattern of the amorphous light-transmitting conductive layer 5 (or the crystalline light-transmitting conductive layer 6) includes, for example, an electrode pattern or a wiring pattern having a stripe shape.

And in this light-transmitting conductive film 1, the thickness of the amorphous light-transmitting conductive layer 5 exceeds 40 nm, and the carrier density in the amorphous light-transmitting conductive layer 5 is 40 × 10 ¹⁹ / It is not less than cm 3. For this reason, the crystallization rate at the time of heating and storage property can be compatible. That is, when heating the light-transmitting conductive film 1 to convert the amorphous light-transmitting conductive layer 5 into the crystalline light-transmitting conductive layer 6, the speed is good. Therefore, the crystalline light-transmitting conductive film 7 can be obtained in a short time. In addition, during storage in a low-temperature environment (e.g., 80° C. or less) before heating, the natural crystallization of the amorphous light-transmitting conductive layer 5 can be suppressed, and the amorphous light-transmitting conductive layer 5 is partially It can suppress crystallization. Therefore, in heating (crystallization) after storage, cracks resulting from the boundary between the crystalline portion and the amorphous portion that may occur during storage can be suppressed.

Therefore, the light-transmitting conductive film 1 can crystallize in a short time while suppressing the crack of the amorphous light-transmitting conductive layer 5 even after storage for a certain period of time, and the productivity of the crystalline light-transmitting conductive film 7 is excellent. Do. Furthermore, after crystallization by heating, the resistance of the crystalline light-transmitting conductive film 7 can be reduced, and conductivity can be improved.

<modification example>

In the above-described embodiment, the light-transmitting conductive film (1) is provided with a transparent substrate (2), a hard coat layer (3), an optical adjustment layer (4), and an amorphous light-transmitting conductive layer (5). The transparent 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 substrate (2), a hard coat layer (3), an optical adjustment layer (4), and an amorphous 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, the hard coat layer 3 and the optical adjustment layer 4 are provided from the viewpoints of scratch resistance and the visibility suppression property of the pattern in the amorphous 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, an amorphous light-transmitting conductive layer (amorphous transparent conductive layer) having a total thickness of 45 nm was formed on the upper surface of the optical adjustment layer.

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 4)

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. In addition, in Examples 4 and 5 and Comparative Examples 2 and 4, a polyethylene terephthalate (PET) film (23 µm in thickness) was used as the transparent substrate.

(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

The hole mobility of the amorphous light-transmitting conductive layer was measured using a Hall effect measuring system (manufactured by BioRad, "HL5500PC"). The carrier density was calculated using the total thickness of the amorphous light-transmitting conductive layer.

(3) Measurement of specific resistance

The specific resistance of the amorphous light-transmitting conductive layer was measured by the four-terminal method. Table 1 shows the results.

(4) Evaluation of crystallization rate in heating

The light-transmitting conductive film of each Example and each comparative example was heated in a 140 degreeC hot air oven for 30 minutes or 60 minutes, and the sample was produced. This sample was immersed in hydrochloric acid having a concentration of 5 wt% and 35° C. for 15 minutes, washed with water and dried, and each time, the resistance between terminals between 15 mm was measured using a tester. At this time, when the resistance between the terminals was 10 kΩ or less, it was determined that crystallization of the amorphous light-transmitting conductive layer was completed.

The case where the time to complete crystallization was 30 minutes or less was evaluated as ◎, the case where the time to complete crystallization was more than 30 minutes and less than 60 minutes was evaluated as ○, and the case where the time to complete crystallization exceeded 60 minutes It evaluated as x. Table 1 shows the results.

(5) Evaluation of preservability (inhibition of crystallization when left to stand)

About the light-transmitting conductive films of each Example and each comparative example, Sample 1 left to stand at 50 degreeC for 15 hours, and Sample 2 left to stand at 80 degreeC for 6 hours were prepared, respectively. These samples were further crystallized by heating in a 150°C hot air oven for 90 minutes. The surface of the light-transmitting conductive layer of this crystallized sample was observed with an optical microscope (100 times magnification, observation area 2 cm in width and height), and the presence or absence of cracks was confirmed.

In both samples 1 and 2, a case where no crack was found is evaluated as ◎, and a case where only sample 1 and no crack was found is evaluated as ○, and a case where a crack was found in both samples 1 and 2 is evaluated as x. Evaluated. Table 1 shows the results.

(6) Evaluation of conductivity after crystallization

The light-transmitting conductive film of each Example and each comparative example was heated in a 140 degreeC hot air oven for 120 minutes, and the amorphous light-transmitting conductive layer was crystallized. The surface resistance of the light-transmitting conductive film of this crystallized sample 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.

One ; Light transmissive conductive film
2 ; Transparent substrate
5; Amorphous light-transmitting conductive layer

Claims (4)

A transparent substrate and an amorphous light-transmitting conductive layer disposed on one side in the thickness direction of the transparent substrate,
The amorphous light-transmitting conductive layer is capable of conversion into crystalline,
The thickness of the amorphous light-transmitting conductive layer exceeds 40 nm,
The light-transmitting conductive film, characterized in that the carrier density in the amorphous light-transmitting conductive layer is 40×10 ¹⁹ /cm 3 or more. The method of claim 1,
The light-transmitting conductive film, wherein the amorphous light-transmitting conductive layer contains an indium-based inorganic oxide. The method of claim 1,
The light-transmitting conductive film, wherein the amorphous light-transmitting conductive layer is an indium-based inorganic oxide layer containing indium and at least one impurity inorganic element. The method of claim 2,
The light-transmitting conductive film, wherein the amorphous light-transmitting conductive layer is an indium-based inorganic oxide layer containing indium and at least one impurity inorganic element.

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