JP7492089B2 - Transparent conductive layer and transparent conductive film - Google Patents

Description

The present invention relates to a transparent conductive layer and a transparent conductive film.

A transparent conductive film on an organic polymer film substrate is known (see, for example, Patent Document 1 below). The transparent conductive film described in Patent Document 1 has a low specific resistance.

JP 2014-157814 A

Depending on the application and purpose, the transparent conductive film is patterned by etching.

For this reason, transparent conductive films are sometimes required to have excellent etching properties.

Etching properties are evaluated, for example, by dissolution time. The dissolution time is the time it takes for the transparent conductive film to be removed per unit thickness of the transparent conductive film when one side of the transparent conductive film in the thickness direction comes into contact with an etching solution and is dissolved and removed. The unit of dissolution time is (seconds/nm). The shorter the dissolution time, the better the etching properties.

However, the transparent conductive film described in Patent Document 1 has the disadvantage that it cannot satisfy the above-mentioned requirements.

The present invention provides a transparent conductive layer and a transparent conductive film with excellent etching properties.

The present invention (1) is a transparent conductive layer comprising an inorganic oxide containing a rare gas having an atomic number greater than that of argon, and includes a transparent conductive layer in which, when the transparent conductive layer is subjected to X-ray diffraction, the half-width of the peak in the (440) plane is 0.27 degrees or less.

The present invention (2) includes a transparent conductive layer described in (1), in which the inorganic oxide is an indium tin composite oxide.

The present invention (3) includes a transparent conductive film having a substrate and a transparent conductive layer described in (1) or (2) in that order toward one side in the thickness direction.

The present invention (4) includes a transparent conductive film described in (3), in which the substrate contains a resin.

The present invention (5) includes a transparent conductive film described in (3) or (4), in which the substrate is a resin.

The transparent conductive layer and transparent conductive film of the present invention have excellent etching properties.

FIG. 1 is a cross-sectional view of one embodiment of a transparent conductive layer of the present invention. 2 is a cross-sectional view of a transparent conductive film having the transparent conductive layer shown in FIG. 1. 1 is a graph showing the relationship between the amount of oxygen introduced and the resistivity in reactive sputtering in Example 1.

1. One embodiment of the transparent conductive layer A transparent conductive layer 1 according to one embodiment of the present invention will be described with reference to Fig. 1. The transparent conductive layer 1 extends in a planar direction. The planar direction is perpendicular to the thickness direction. The transparent conductive layer 1 is crystalline.

1.1 Inorganic oxide contained in the transparent conductive layer The transparent conductive layer 1 contains an inorganic oxide. Examples of the inorganic oxide include metal oxides. The metal oxide includes at least one metal selected from the group consisting of In, Sn, Zn, Ga, Sb, Nb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, and W. Specifically, the material of the transparent conductive layer 1 preferably includes indium zinc composite oxide (IZO), indium gallium zinc composite oxide (IGZO), indium gallium composite oxide (IGO), indium tin composite oxide (ITO), and antimony tin composite oxide (ATO), and preferably includes indium tin composite oxide (ITO) from the viewpoint of improving etching properties.

1.2 Content of tin oxide (SnO ₂ ) The content of tin oxide (SnO ₂ ) in the indium tin composite oxide is, for example, 0.5 mass% or more, preferably 3 mass% or more, more preferably 6 mass% or more, and even more preferably 8 mass% or more, and is, for example, less than 50 mass%, preferably 25 mass% or less, and more preferably 15 mass% or less. If the content of tin oxide in the indium tin composite oxide is the above-mentioned lower limit or more, the etching property is excellent. If the content of tin oxide (SnO ₂ ) in the indium tin composite oxide is the above-mentioned upper limit or less, the transparent conductive layer 1 is likely to have both excellent resistance properties and etching property.

1.3 Rare gas having an atomic number larger than that of argon contained in inorganic oxide The above-mentioned inorganic oxide contains a rare gas having an atomic number larger than that of argon. The rare gas 2 having an atomic number larger than that of argon is present throughout the entire transparent conductive layer 1 in the thickness direction, as shown in the enlarged view at the top of FIG.

The transparent conductive layer 1 is a composition comprising an inorganic oxide (preferably a metal oxide) mixed with a rare gas having an atomic number higher than that of argon.

Examples of rare gases with atomic numbers greater than argon include krypton, xenon, and radon. These can be used alone or in combination. Preferred rare gases with atomic numbers greater than argon include krypton and xenon, and more preferably, krypton (Kr) is used from the viewpoints of low cost and excellent electrical conductivity.

The method of identifying the rare gas having an atomic number greater than that of argon is not limited. For example, the rare gas having an atomic number greater than that of argon in the transparent conductive layer 1 is identified (the presence or absence is determined) by Rutherford backscattering spectrometry, secondary ion mass spectrometry, laser resonance ionization mass spectrometry, and/or X-ray fluorescence analysis, but preferably, from the viewpoint of analytical simplicity, it is identified by X-ray fluorescence analysis. Details of X-ray fluorescence analysis are described in the examples. When Rutherford backscattering analysis is performed to quantify the rare gas having an atomic number greater than that of argon, the content of the rare gas having an atomic number greater than that of argon is not equal to or greater than the detection limit (lower limit), and therefore the content cannot be quantified. On the other hand, when X-ray fluorescence analysis is performed, if the presence of the rare gas having an atomic number greater than that of argon is identified, it is determined that the transparent conductive layer 1 includes a region in which the content of the rare gas having an atomic number greater than that of argon is 0.0001 atom% or more.

The content of the rare gas having an atomic number greater than that of argon in the inorganic oxide (transparent conductive layer 1) is, for example, 0.0001 atom% or more, preferably 0.001 atom% or more, and for example, 1.0 atom% or less, more preferably 0.7 atom% or less, even more preferably 0.5 atom% or less, particularly preferably 0.3 atom% or less, particularly preferably 0.2 atom% or less, and most preferably 0.15 atom% or less. If the content of the rare gas having an atomic number greater than that of argon in the inorganic oxide (transparent conductive layer 1) is within the above range, the etching properties of the transparent conductive layer 1 can be improved.

Alternatively, a rare gas 2 having an atomic number greater than that of argon is present (distributed) in a portion of the transparent conductive layer 1 in the thickness direction, as shown in the enlarged view at the bottom of Figure 1. In the embodiment shown in the enlarged view at the bottom of Figure 1, the transparent conductive layer 1 has a first region 3 and a second region 4 in that order toward one side in the thickness direction.

The first region 3 contains a rare gas 2 having an atomic number larger than that of argon. The first region 3 is allowed to contain argon. Preferably, the first region 3 does not contain argon. The ratio of the thickness of the first region 3 in the transparent conductive layer 1 is, for example, 0.95 or less, preferably 0.8 or less, more preferably 0.7 or less, even more preferably 0.6 or less, and even more preferably 0.48 or less, and is, for example, 0.01 or more, preferably 0.1 or more, and even more preferably 0.3 or more. The thickness of the first region 3 is, for example, 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, even more preferably more than 40 nm, and especially preferably 50 nm or more, and is, for example, less than 300 nm, preferably 250 nm or less, more preferably 150 nm or less, even more preferably 100 nm or less, and even more preferably 70 nm or less.

The content of the rare gas having an atomic number larger than that of argon in the first region 3 is, for example, 0.0001 atom% or more, preferably 0.001 atom% or more, and for example, 1.0 atom% or less, more preferably 0.7 atom% or less, even more preferably 0.5 atom% or less, particularly preferably 0.3 atom% or less, particularly preferably 0.2 atom% or less, and most preferably 0.15 atom% or less.
If the content of the rare gas having an atomic number larger than that of argon in the first region 3 is within the above range, the etching properties of the first region 3 can be improved.

The second region 4 does not contain a rare gas 2 having an atomic number greater than that of argon. On the other hand, the second region 4 may contain, for example, argon or may not contain argon. Preferably, the second region 4 does not contain a rare gas 2 having an atomic number greater than that of argon, and contains argon. The presence of argon is confirmed, for example, by performing Rutherford backscattering analysis. The ratio of the thickness of the second region 4 to the thickness of the first region 3 is, for example, 0.99 or more, preferably 0.9 or more, preferably 1.2 or more, and, for example, 2.0 or less, preferably 1.5 or less. The thickness of the second region 4 is, for example, 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more, even more preferably 30 nm or more, particularly preferably more than 40 nm, and particularly preferably 50 nm or more, and for example, less than 300 nm, preferably 250 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, particularly preferably 100 nm or less, particularly preferably 75 nm or less, and most preferably 70 nm or less.

In the sputtering described later, when the sputtering gas contains argon, a large amount of argon is taken into the transparent conductive layer 1. In contrast, in the present embodiment in which the sputtering gas contains a rare gas with an atomic number larger than that of argon and does not contain argon, the transparent conductive layer 1 (or the first region 3) contains a rare gas with an atomic number larger than that of argon. In other words, the type of rare gas contained in the transparent conductive layer 1 differs between regions. The gas contained in the transparent conductive layer 1 acts as an impurity element and affects the crystal orientation of the transparent conductive layer 1 depending on the type of impurity element and the size of the atom. This effect is particularly large in the present embodiment in which the substrate 6 contains a resin. In the present application, the transparent conductive layer 1 (or the first region 3) contains a rare gas with an atomic number larger than that of argon, so that the orientation in the (440) plane can be suitably controlled, and as a result, the etching property of the transparent conductive layer 1 (including the first region 3) is improved.

1.4 Peak in the (440) plane in X-ray diffraction There is a peak in the (440) plane when X-ray diffraction is performed on the transparent conductive layer 1. The (440) plane is a specific peak contained in the spectrum obtained when the crystalline transparent conductive layer 1 is subjected to X-ray diffraction.

1.4.1 Half-width of peak in (440) plane The half-width of the peak in the (440) plane in X-ray diffraction is 0.27 degrees or less.

On the other hand, if the half-width of the peak in the (440) plane in X-ray diffraction exceeds 0.27 degrees, the etching ability of the transparent conductive layer 1 is poor.

In contrast, when transparent conductive layer 1 is subjected to X-ray diffraction, the half-width of the peak in the (440) plane is 0.27 degrees or less, so that transparent conductive layer 1 has excellent etching properties.

When the transparent conductive layer 1 is subjected to X-ray diffraction, the half-width of the peak in the (440) plane is preferably 0.26 degrees or less, more preferably 0.25 degrees or less, even more preferably 0.24 degrees or less, particularly preferably 0.23 degrees or less, and most preferably 0.22 degrees or less.

Furthermore, when the transparent conductive layer 1 is subjected to X-ray diffraction, the half-width of the peak in the (440) plane is, for example, 0.01 degrees or more, preferably 0.05 degrees or more, more preferably 0.10 degrees or more, and even more preferably 0.15 degrees or more.

If the half-width of the peak in the (440) plane is equal to or greater than the lower limit described above, side etching of the transparent conductive layer 1 due to excessive solubility can be suppressed. Side etching is one of the phenomena in which the transparent conductive layer 1 is excessively removed when the transparent conductive layer 1 is shaped into a pattern by etching. In detail, when an etching resist having a pattern is formed on one side of the transparent conductive layer 1 in the thickness direction, and the transparent conductive layer 1 exposed from the pattern comes into contact with an etching solution, the etching solution removes the transparent conductive layer 1 toward the other side, and the transparent conductive layer 1 in contact with the end of the etching resist is also excessively removed. At this time, when projected in the thickness direction, in the transparent conductive layer 1 overlapping the end of the etching resist, one side and its vicinity are largely removed toward the inside in the surface direction of the etching resist, while the other side and its vicinity are largely removed toward the inside in the surface direction of the etching resist, or are hardly removed at all.

There is no limitation on the method for bringing the half-width of the peak in the (440) plane in X-ray diffraction into the above range.

The half-width of the X-ray diffraction peak in the (440) plane is measured based on the description in the examples below.

1.5 Dissolution time of transparent conductive layer 1 The dissolution time when the transparent conductive layer 1 is immersed in 7 mass % hydrochloric acid is, for example, 20 (seconds/nm) or less, preferably 18 (seconds/nm) or less, more preferably 17 (seconds/nm) or less, and even more preferably 16 (seconds/nm) or less, and is, for example, 1 (seconds/nm) or more. A short dissolution time means excellent etching properties. The measurement of the dissolution time will be described in the following examples.

1.6 Other properties of the transparent conductive layer 1 The crystal grain size in the transparent conductive layer 1 is, for example, 0.05 μm or more, preferably 0.1 μm or more, more preferably 0.15 μm or more, and, for example, 3 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less, even more preferably less than 0.4 μm, particularly preferably 0.3 μm or less, and particularly preferably 0.25 μm or less. If the crystal grain size is equal to or greater than the above-mentioned lower limit, the etching property is excellent. If the crystal grain size is equal to or less than the above-mentioned upper limit, even if a substrate 6 containing a flexible resin is used, cracks are unlikely to occur in the transparent conductive layer 1. The crystal grain size can be determined, for example, by FE-SEM observation. Details of the determination method will be described in the following examples.

The thickness of the transparent conductive layer 1 is, for example, 15 nm or more, preferably 35 nm or more, more preferably 50 nm or more, even more preferably 75 nm or more, even more preferably 100 nm or more, and particularly preferably 120 nm or more. The thickness of the transparent conductive layer 1 is, for example, 500 nm or less, preferably 300 nm or less, more preferably 250 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less, even more preferably 140 nm or less, and particularly preferably 135 nm or less.

The total light transmittance of the transparent conductive layer 1 is, for example, 75% or more, preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the total light transmittance of the transparent conductive layer 1 is not limited. The upper limit of the total light transmittance of the transparent conductive layer 1 is, for example, 100%.

The transparent conductive layer 1 has a resistivity of, for example, 5.0×10 ⁻⁴ Ω·cm or less, or preferably 3×10 ⁻⁴ Ω·cm or less, and for example, 0.1×10 ⁻⁴ Ω·cm or more, or preferably 1.1×10 ⁻⁴ Ω·cm or more. The resistivity is measured by a four-terminal method.

1.7 Transparent conductive film 5
Next, a transparent conductive film 5 including the above-mentioned transparent conductive layer 1 will be described with reference to Fig. 2. The transparent conductive film 5 extends in the planar direction. The transparent conductive film 5 includes a substrate 6 and a transparent conductive layer 1 in this order toward one side in the thickness direction. That is, in the transparent conductive film 5 of this embodiment, the substrate 6 and the transparent conductive layer 1 are disposed in this order toward one side in the thickness direction. In this embodiment, the transparent conductive film 5 includes only the substrate 6 and the transparent conductive layer 1.

1.8 Substrate 6
In this embodiment, the substrate 6 forms the other surface of the transparent conductive film 5 in the thickness direction. The substrate 6 improves the mechanical strength of the transparent conductive film 5. The substrate 6 extends in the planar direction. The substrate 6 includes, for example, a resin. If the substrate 6 includes a resin, it is possible to achieve both excellent resistance characteristics and etching properties in the transparent conductive layer 1. Preferably, the substrate 6 is made of a resin. If the substrate 6 is made of a resin, it is possible to realize a transparent conductive film 5 having flexibility in addition to achieving both excellent resistance characteristics and etching properties in the transparent conductive layer 1. The resin will be described later. In this embodiment, the substrate 6 is not adjacent to a glass plate (not shown). In this embodiment, the other surface of the substrate 6 in the thickness direction does not contact the glass plate.

1.8.1 Layer structure of substrate 6 In this embodiment, the substrate 6 includes a substrate sheet 61 and a functional layer 60 in this order in the thickness direction. In this embodiment, the functional layer 60 is a single layer. The functional layer 60 contacts one side of the substrate sheet 61 in the thickness direction. The functional layer 60 is preferably a hard coat layer 62.
In this embodiment, the substrate 6 preferably includes a substrate sheet 61 and a hard coat layer 62 in this order toward the other side in the thickness direction.

1.8.1.1 Base sheet 61
The base sheet 61 has flexibility. Examples of the base sheet 61 include a resin film. The resin in the resin film is not limited. Examples of the resin include polyester resin, acrylic resin, olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, polystyrene resin, and norbornene resin. As the resin, a polyester resin is preferably used from the viewpoints of transparency and mechanical strength.
Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, and preferably PET.

The thickness of the base sheet 61 is preferably 1 μm or more, more preferably 10 μm or more, and even more preferably 30 μm or more. The thickness of the base sheet 61 is preferably 300 μm or less, more preferably 200 μm or less, even more preferably 150 μm or less, and particularly preferably 100 μm or less. The ratio of the thickness of the base sheet 61 to the thickness of the base material 6 is, for example, 0% or more, preferably 50% or more, even more preferably 80% or more, and, for example, 99.99% or less, preferably 99% or less.

1.8.1.2 Hard Coat Layer 62
The hard coat layer 62 makes it difficult for scratches to form on one side of the transparent conductive layer 1 in the thickness direction. The hard coat layer 62 contacts one side of the base sheet 61 in the thickness direction. The hard coat layer 62 is made of a resin. Specifically, the hard coat layer 62 is, for example, a cured layer of a curable composition containing a curable resin. Examples of the curable resin include acrylic resin, urethane resin, amide resin, silicone resin, epoxy resin, and melamine resin. Examples of the curable resin include acrylic resin. The thickness of the hard coat layer 62 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. The ratio of the thickness of the hard coat layer 62 to the thickness of the base sheet 61 is, for example, 0.1% or more, preferably 1% or more, and, for example, 100% or less, preferably 50% or less. The thickness of the hard coat layer 62 corresponds to the thickness of the functional layer 60.

1.8.2 Thickness of Substrate 6 The thickness of the substrate 6 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 25 μm or more, and for example, 500 μm or less, preferably 200 μm or less, more preferably 100 μm or less. The thickness of the substrate 6 is the total thickness of the substrate sheet 61 and the hard coat layer 62.

1.8.3 Physical properties of substrate 6 The total light transmittance of the substrate 6 is, for example, 75% or more, preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the total light transmittance of the substrate 6 is not limited. The upper limit of the total light transmittance of the substrate 6 is, for example, 100%. The total light transmittance of the substrate 6 is determined based on JIS K 7375-2008. The total light transmittance of the following members is determined based on the same method as above.

The substrate 6 can be a commercially available product.

1.9 Transparent conductive layer 1
In the transparent conductive film 5 of this embodiment, the transparent conductive layer 1 forms one surface of the transparent conductive film 5 in the thickness direction. The transparent conductive layer 1 is disposed on one surface of the substrate 6 in the thickness direction. The transparent conductive layer 1 contacts one surface of the substrate 6 in the thickness direction. In other words, the other surface of the transparent conductive layer 1 in the thickness direction contacts the substrate 6. In this embodiment, the other surface of the transparent conductive layer 1 contacts one surface of the hard coat layer 62 (functional layer 60) in the thickness direction.

As shown in the enlarged view at the bottom of FIG. 1, when the transparent conductive layer 1 has the first region 3 and the second region 4, the first region 3 is preferably disposed on one side of the substrate 6 in the thickness direction. Preferably, the first region 3 contacts one side of the hard coat layer 62 (see FIG. 2) in the thickness direction. As shown in the enlarged view at the bottom of FIG. 1 and the enlarged view at the bottom of FIG. 2, when the transparent conductive layer 1 has the first region 3 and the second region 4, the transparent conductive film 5 includes the substrate sheet 61, the hard coat layer 62, the first region 3, and the second region 4 in this order toward one side in the thickness direction. In other words, the second region 4 is disposed on the opposite side of the substrate 6 from the first region 3 in the thickness direction.

1.10 Thickness and other physical properties of transparent conductive film 5 The thickness of the transparent conductive film 5 is, for example, 2 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and for example, 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less.

The total light transmittance of the transparent conductive film 5 is, for example, 75% or more, preferably 80% or more, and, for example, 100% or less.

1.11 Method for Producing Transparent Conductive Film 5 In this method, for example, each layer is disposed by a roll-to-roll method.

1.11.1 Preparation of Substrate 6 First, the substrate 6 is prepared. Specifically, a curable composition is applied to one side of a substrate sheet 61. Then, the curable resin in the curable composition is cured by heat or ultraviolet light irradiation. In this way, a hard coat layer 62 is formed on one side of the substrate sheet 61. In this way, the substrate 6 is prepared.

1.11.2 Formation of Transparent Conductive Layer 1 Then, the transparent conductive layer 1 is formed on one surface in the thickness direction of the substrate 6. Specifically, first, an amorphous transparent conductive layer is formed on one surface in the thickness direction of the substrate 6, and then the amorphous transparent conductive layer is converted to a crystalline material to form the transparent conductive layer 1.

1.11.2.1 Formation of amorphous transparent conductive layer (sputtering process)
To form the amorphous transparent conductive layer, for example, sputtering, preferably reactive sputtering, is carried out.

In sputtering, a sputtering device is used. The sputtering device is equipped with a single deposition roll and a single deposition chamber.

The deposition chamber is capable of supplying a sputtering gas into the deposition chamber. The sputtering gas may be a rare gas having an atomic number greater than that of argon. Examples of rare gases having an atomic number greater than that of argon include krypton, xenon, and radon, and preferably krypton (Kr). The sputtering gas preferably does not contain argon.

The sputtering gas is preferably mixed with a reactive gas. An example of the reactive gas is oxygen. The ratio of the amount of reactive gas introduced to the total amount of sputtering gas and reactive gas introduced is, for example, 0.1 flow% or more, preferably 0.5 flow% or more, and is, for example, less than 5.0 flow%, preferably 4.0 flow% or less, more preferably 3.5 flow% or less.

A single target is placed in a single deposition chamber. The target is, for example, a sintered body of the metal oxide described above.

As shown in the lower diagram of Figure 1, to provide the transparent conductive layer 1 with the first region 3 and the second region 4 described above, a first sputtering process and a second sputtering process are carried out in sequence. Specifically, a first and a second film formation chamber are provided in a sputtering device. The first and the second film formation chambers are arranged in sequence toward the downstream side in the transport direction of the substrate 6.

1.11.2.2 First sputtering step In the first sputtering step, a first sputtering gas is introduced into the first deposition chamber. The first sputtering gas includes a rare gas having an atomic number greater than that of argon. Preferably, the first sputtering gas is a rare gas having an atomic number greater than that of argon. A first region 3 is formed by the first sputtering step.

1.11.2.3 Second sputtering step In the second sputtering step, a second sputtering gas is introduced into the second film formation chamber. The second sputtering gas contains argon. Preferably, the second sputtering gas is argon. By the second sputtering step, the second region 4 is formed on one side of the first region 3.

The air pressure inside the sputtering apparatus is, for example, 1.0 Pa or less, and, for example, 0.01 Pa or more.

This produces a laminate including the substrate 6 and the amorphous transparent conductive layer. When the sputtering apparatus includes a first and a second deposition chamber, the amorphous transparent conductive layer includes a first region 3 and a second region 4.

1.11.2.4 Conversion of Amorphous Transparent Conductive Layer to Crystalline Thereafter, the amorphous transparent conductive layer is converted to a crystalline state to form the transparent conductive layer 1.

To convert the transparent conductive layer 1 to a crystalline form, the amorphous transparent conductive layer (or the laminate comprising the layer) is heated.

The heating temperature is, for example, 80°C or higher, preferably 110°C or higher, more preferably, even more preferably, 130°C or higher, particularly preferably, 150°C or higher, and, for example, 200°C or lower, preferably, 180°C or lower, more preferably, 175°C or lower, and more preferably, 170°C or lower. The heating time is, for example, 1 minute or more, preferably, 3 minutes or more, more preferably, 5 minutes or more, and, for example, 5 hours or less, preferably, 3 hours or less, and more preferably, 2 hours or less. The heating is performed, for example, in a vacuum or in the atmosphere. From the viewpoint of obtaining excellent etching properties of the transparent conductive layer 1, the heating is preferably performed in the atmosphere.

Alternatively, the transparent conductive film 5 having an amorphous transparent conductive layer can be left in the atmosphere at a temperature in the range of 20°C or higher and lower than 80°C for, for example, 10 hours or more, preferably 24 hours or more, to convert the amorphous transparent conductive layer to a crystalline one.

1.12 Uses of the Transparent Conductive Film 5 The transparent conductive film 5 is used, for example, in articles. Examples of the articles include optical articles. More specifically, examples of the articles include touch sensors, electromagnetic wave shields, dimming elements, photoelectric conversion elements, heat ray control members, light-transmitting antenna members, light-transmitting heater members, image display devices, and lighting.

2. Effects of the embodiment The transparent conductive layer 1 provided on the transparent conductive film 5 has excellent etching properties. In other words, the dissolution time of the transparent conductive layer 1 is short.

The transparent conductive layer 1 is etched and patterned depending on the type of article described above.

3. Modifications In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, each modification can achieve the same effects as those in the embodiment, unless otherwise specified. Furthermore, the embodiment and the modifications can be appropriately combined.

In a modified example, the transparent conductive film 5 has a substrate 6, a second region 4, and a first region 3, arranged in that order toward one side in the thickness direction.

In another variant, the transparent conductive layer 1 has a repeating structure of first regions 3 and second regions 4.

In a modified example (not shown), the functional layer 60 is a multi-layer structure. The functional layer 60 is arranged on one side and the other side of the base sheet 61 in the thickness direction. For example, the functional layer 60 includes an optical adjustment layer and a hard coat layer. The optical adjustment layer is arranged on one side of the base sheet 61. The hard coat layer is arranged on the other side of the base sheet 61.

The present invention will be described in more detail below with reference to examples. Note that the present invention is not limited to the examples. In addition, the specific numerical values of the compounding ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (a numerical value defined as "equal to or less than") or lower limit (a numerical value defined as "equal to or more than" or "exceeding") of the corresponding compounding ratio (content ratio), physical property value, parameter, etc. described in the above "Form for carrying out the invention".

Example 1
A substrate 6 having a thickness of 52 μm was prepared.

Specifically, a substrate sheet 61 (50 μm thick, manufactured by Toray Industries, Inc.) made of PET was prepared. Next, a hard coat composition (ultraviolet-curable resin containing acrylic resin) was applied to one side of the substrate sheet 61 in the thickness direction to form a coating film. Next, the coating film was cured by ultraviolet irradiation. As a result, a hard coat layer 62 having a thickness of 2 μm was formed on one side of the substrate sheet 61. In this way, a substrate 6 was produced that had the substrate sheet 61 and the hard coat layer 62 in order toward one side in the thickness direction.

An amorphous transparent conductive layer was formed on one side of the substrate 6 by reactive sputtering (execution of the sputtering process). The reactive sputtering conditions were as follows:

A sintered body of indium oxide and tin oxide was used as the target. The tin oxide concentration in the sintered body was 10 mass %. A voltage was applied to the target using a DC power source. The horizontal magnetic field strength on the target was 90 mT. In addition, the film formation chamber in the DC magnetron sputtering device was evacuated until the ultimate vacuum in the film formation chamber reached 0.9×10 ⁻⁴ Pa, and a degassing process was performed on the substrate 6. Thereafter, Kr as a sputtering gas and oxygen as a reactive gas were introduced into the film formation chamber, and the pressure in the film formation chamber was set to 0.2 Pa. The ratio of the amount of oxygen introduced to the total amount of Kr and oxygen introduced into the film formation chamber was about 2.5 flow %. The amount of oxygen introduced was adjusted to be within the region X of the resistivity-oxygen introduction amount curve as shown in FIG. 3, so that the resistivity of the amorphous krypton-containing transparent conductive layer was 6.6×10 ⁻⁴ Ω·cm. The resistivity vs. oxygen introduction amount curve shown in Figure 3 can be created by investigating in advance the dependence of the resistivity of an amorphous krypton-containing transparent conductive layer on the amount of oxygen introduced when the layer is formed by a reactive sputtering method under the same conditions as described above except for the amount of oxygen introduced.

The laminate was then heated in a hot air oven at 160°C. This converted the amorphous transparent conductive layer into a crystalline one, forming transparent conductive layer 1. The thickness of transparent conductive layer 1 was 130 nm.

This resulted in the production of a transparent conductive film 5 having a substrate 6 and an amorphous transparent conductive layer arranged in that order toward one side in the thickness direction.

Example 2
A transparent conductive film was produced in the same manner as in Example 1. However, in forming the amorphous transparent conductive layer, the following changes were made, and the first sputtering step and the second sputtering step were carried out in that order.

The first sputtering step was carried out in the same manner as in Example 1. However, the amount of oxygen introduced was changed so that the resistivity of the amorphous krypton-containing transparent conductive layer was 6.5×10 ⁻⁴ Ω·cm, and the ratio of the amount of oxygen introduced to the total amount of Kr and oxygen introduced was changed to 2.6 flow %. An amorphous first region 3 was formed by the first sputtering step. The thickness of the first region 3 was 55 nm.

Subsequently, a second sputtering process was carried out. At this time, the sputtering gas was changed to argon, the pressure in the sputtering film formation apparatus was changed to 0.4 Pa, the amount of oxygen introduced was changed so that the resistivity of the amorphous second region 4 was 6.5×10 ⁻⁴ Ω·cm, and the ratio of the amount of oxygen introduced to the total amount of Ar and oxygen introduced was changed to 1.5 flow %. An amorphous second region 4 was formed by the second sputtering process. The thickness of the second region 4 was 75 nm.

<Comparative Example 1>
The first sputtering step and the second sputtering step were carried out in the same manner as in Example 2, and then a transparent conductive film 5 was produced, except for the following points.

In the first sputtering process, the sputtering gas was changed to argon, and the air pressure in the sputtering deposition apparatus was changed to 0.4 Pa. The thickness of the first region 3 was 19 nm.

In the second sputtering step, the tin oxide concentration in the target was changed to 3 mass%. The thickness of the second region 4 was 3 nm.

<Comparative Example 2>
The first sputtering step and the second sputtering step were carried out in the same manner as in Example 2, and then a transparent conductive film 5 was produced, except for the following points.

In the first sputtering step, the tin oxide concentration in the sintered body was changed to 3 mass%. The amount of oxygen introduced was changed so that the resistivity in the first region 3 was 6.6×10 ⁻⁴ Ω·cm, and the ratio of the amount of oxygen introduced to the total amount of Kr and oxygen introduced was changed to 2.5 flow%. The amorphous transparent conductive layer was crystallized by contacting it with a heating roll in a vacuum heating device. The heating temperature was 160° C., and the heating time was 0.1 hours. The thickness of the first region 3 was 11 nm.

In the second sputtering step, the sputtering gas was changed from Kr to argon. The thickness of the second region 4 was 11 nm.

<Evaluation>
The transparent conductive films 5 of the respective Examples and Comparative Examples were evaluated for the following items.

<Thickness>
The thickness of the transparent conductive layer 1 was measured by FE-TEM observation. Specifically, first, a sample for cross-sectional observation of the transparent conductive layer 1 was prepared by FIB microsampling. In the FIB microsampling, an FIB device (trade name "FB2200", manufactured by Hitachi) was used, and the acceleration voltage was set to 10 kV. Next, the thickness of the transparent conductive layer 1 in the sample for cross-sectional observation was measured by FE-TEM observation. In the FE-TEM observation, an FE-TEM device (trade name "JEM-2800", manufactured by JEOL) was used, and the acceleration voltage was set to 200 kV.

In addition, in Example 2, Comparative Example 1, and Comparative Example 2, before forming the second region 4, a sample for cross-sectional observation was prepared from the first region 3, and the sample was observed using FE-TEM to calculate the thickness of the first region 3.

The thickness of the second region 4 was calculated by subtracting the thickness of the first region 3 from the thickness of the transparent conductive layer 1.

<Half-width of X-ray diffraction peak in (440) plane>
The X-ray diffraction peaks of the transparent conductive layer 1 were obtained by X-ray diffraction measurement using a horizontal X-ray diffractometer (product name "SmartLab", manufactured by Rigaku Corporation) under the following measurement conditions. The results are shown in Table 1.

[Measurement condition]
Parallel beam optical arrangement Light source: CuKα radiation (wavelength: 1.54059 Å)
Output: 45kV, 200mA
Entrance side slit system: Soller slit 5.0°
Entrance slit: 1.000 mm
Receiving slit: 20.100 mm
Receiving side slit: Parallel slit analyzer (PSA) 0.114 deg.
Detector: Multi-dimensional pixel detector Hypix-3000
Sample stage: A specimen in which glass was attached to the substrate 6 of a transparent conductive film 5 via an adhesive layer was placed on a sample plate (4-inch wafer sample plate).
Scan axis: 2θ/θ (Out of Plane measurement)
Step interval: 0.02°
Measurement speed: 0.8°/min Measurement range: 10° to 90°

The X-ray peak profile was obtained by subtracting the background from the substrate 6 (substrate 6 heated under the same conditions as the transparent conductive layer 1 in each example and comparative example). Then, using analysis software (software name "SmartLab StudioII"), an X-ray diffraction peak profile corresponding to the (440) plane was created so that 2θ was in the range of 49.8° to 51.8°, and the half-width (FWHM, unit: °) of the X-ray diffraction peak in the (440) plane was obtained by fitting the X-ray diffraction peak (peak shape: split-type Pearson VII function, background type: B-spline, fitting condition: automatic).

In the measurement of the half-width of the X-ray diffraction peak in the (440) plane, the following procedure is carried out.
[1] A baseline passing through the two tails of the peak in the (440) plane is plotted on an X-ray diffraction chart.
[2] The intensity from the peak top to the baseline on the (440) plane is obtained as the peak intensity.
[3] The intensity at half the peak intensity in the (440) plane is determined.
[4] For the peak on the (440) plane, 2θ (degrees) between two points at half maximum is taken as the full width at half maximum (FWHM).

(440) is determined using an X-ray diffraction apparatus equipped with a program including the above-mentioned procedure.

<Crystal Grain Size>
One surface of the transparent conductive layer 1 was observed with an FE-SEM (apparatus; Hitachi, SU8020) to determine the crystal grain size of the transparent conductive layer 1. Specifically, the transparent conductive layer 1 was fixed to a stand, and then surface FE-SEM observation (accelerating voltage; 0.8 kV, observed image: secondary electron image) was performed to photograph the transparent conductive layer 1 in a planar view. The magnification was adjusted so that the crystal grains could be clearly observed.

Next, the captured images were subjected to image analysis to determine the area of the region defined by the grain boundaries (regions within each grain boundary) from the number of pixels present in that region, and the diameter of a circle with the same area as that region was calculated as the grain size (equivalent circle diameter). The results are shown in Table 1.

<Dissolution time (etching property)>
The dissolution time (sec/nm) of the transparent conductive layer 1 was measured to evaluate the etching property of the transparent conductive layer 1. The results are shown in Table 1.

Specifically, a cycle including the following first step, the following second step, and the following third step, in that order, was performed once or multiple times on the transparent conductive film 5.

If it was determined in the third step that the etching was complete, the cycle was terminated. On the other hand, if it was determined in the third step that the etching was not complete, the cycle was repeated.

First step: the transparent conductive film 5 was immersed in hydrochloric acid having a concentration of 7% by mass at a temperature of 35° C. The immersion time was 30 seconds.
Second step: The transparent conductive film 5 was washed with water and then dried.
Third step: On one surface (exposed surface) of the transparent conductive layer 1 of the transparent conductive film 5, the resistance between a pair of terminals separated by a distance of 15 mm (terminal-to-terminal resistance) was measured using a surface resistance measuring tester.

In the third step, if the measured inter-terminal resistance exceeded 100 kΩ or was impossible to measure, it was determined that the dissolution (etching) of the transparent conductive layer 1 was completed in the first step of the cycle to which the third step belonged.

The dissolution time (more specifically, the dissolution time per unit thickness) was calculated by dividing the cumulative immersion time (dissolution time) of multiple first steps by the thickness of the transparent conductive layer 1. A shorter dissolution time indicates better etching properties of the transparent conductive layer 1.

<Confirmation of Kr atoms in transparent conductive layer 1>
It was confirmed that the transparent conductive layers 1 in Examples 1 and 2 and Comparative Example 2 contained Kr atoms as follows.

First, using a scanning X-ray fluorescence analyzer (product name "ZSX Primus IV", manufactured by Rigaku Corporation), X-ray fluorescence analysis was repeated five times under the following measurement conditions, and the average value of each scanning angle was calculated to create an X-ray spectrum. It was then confirmed that a peak appeared at a scanning angle of about 28.2° in the created X-ray spectrum, thereby confirming that Kr atoms are contained in the transparent conductive layer 1.

[Measurement condition]
Spectrum: Kr-KA
Measurement diameter: 30 mm
Atmosphere: Vacuum Target: Rh
Tube voltage: 50 kV
Tube current: 60mA
Primary filter: Ni40
Scanning angle (deg): 27.0 to 29.5
Step (deg): 0.020
Speed (deg/min): 0.75
Attenuator: 1/1
Slit: S2
Analyzing crystal: LiF(200)
Detector: SC
PHA: 100-300

Transparent conductive films are used in optical articles.

The above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be interpreted as being limiting. Modifications of the present invention that are obvious to a person skilled in the art are included in the scope of the claims below.

1 Transparent conductive layer 2 Rare gas 5 Transparent conductive film 6 Substrate

Claims (4)

a transparent conductive layer including an inorganic oxide containing krypton ,
the half-width of a peak in a (440) plane when the transparent conductive layer is subjected to X-ray diffraction is 0.25 degrees or less;
the inorganic oxide is an indium tin composite oxide,
The transparent conductive layer, wherein the indium tin composite oxide has a tin oxide content of 8% by mass or more and 15% by mass or less . A transparent conductive film comprising a substrate and the transparent conductive layer according to claim 1, arranged in that order toward one side in the thickness direction. The transparent conductive film according to claim 2, wherein the substrate contains a resin. The transparent conductive film according to claim 2, wherein the substrate is a resin.