JP2021018900A - Manufacturing method of conductive film, conductive film, sensor, touch panel and picture display unit - Google Patents

Abstract

To provide a conductive film capable of achieving a cost reduction while suppressing electric short-circuiting and a manufacturing method thereof, and also to provide a sensor, a touch panel and a picture display unit equipped with the conductive film.SOLUTION: A manufacturing method of a conductive film 10 having an optically transmissive substrate 11 and a conductive part 13 arranged on a first face 11A side of the optically transmissive substrate 11 includes: a process of forming two or more electrical insulation wall parts 12 alienated with each other on the first face 11A side of the optically transmissive substrate 11; and a process of filling a gap between the wall parts 12 with conductive fiber dispersion including conductive fibers to form the conductive part 13.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a conductive film, a conductive film, a sensor, a touch panel, and an image display device.

In recent years, an image display device such as a smartphone or a tablet terminal may be provided with a touch panel capable of directly inputting information by touching the image display surface with a finger or the like.

The touch panel usually includes a conductive film having a conductive portion on a light-transmitting base material. Indium tin oxide (ITO) is mainly used as the conductive material for the conductive portion of the light-transmitting conductive film. However, since ITO has no flexibility, cracks are likely to occur in the conductive portion when a flexible base material is used as the light-transmitting base material.

For this reason, it is currently being studied to use metal nanowires having a fiber diameter of nano size as a conductive material constituting the conductive portion instead of ITO (see, for example, Patent Document 1).

JP-A-2018-88318

Currently, the patterning of the conductive portion is performed by removing an unnecessary portion from the conductive layer containing the metal nanowires formed on the light transmissive substrate by etching. On the other hand, metal nanowires are an expensive material. For this reason, the metal nanowires removed by etching are wasted when patterning the conductive portion, resulting in high cost.

Further, when the conductive layer is etched, metal nanowires may remain in the etched portion. If the metal nanowires remain in this portion, the remaining metal nanowires and the migration of metal ions from the conductive portion are combined, and an electrical short circuit is likely to occur.

The present invention has been made to solve the above problems. That is, it is an object of the present invention to provide a conductive film capable of reducing costs and suppressing an electrical short circuit, a sensor provided with the conductive film, a touch panel, and an image display device.

The present invention includes the following inventions.
[1] A method for producing a conductive film including a light-transmitting base material and a conductive portion arranged on the first surface side of the light-transmitting base material, wherein the first of the light-transmitting base materials. A step of forming two or more electrically insulating wall portions separated from each other on the surface side, and a step of filling the wall portions with a conductive fiber dispersion liquid containing conductive fibers to form a conductive portion. A method for producing a conductive film.

[2] The method for producing a conductive film according to the above [1], wherein the wall portion contains a resin.

[3] A conductive film comprising a light-transmitting base material and a conductive portion arranged on the first surface side of the light-transmitting base material, on the first surface side of the light-transmitting base material. A conductive film having two or more electrically insulating wall portions arranged and separated from each other, the conductive portion containing conductive fibers, and being filled between the wall portions.

[4] The conductive film according to the above [3], wherein the thickness of the wall portion is larger than the thickness of the conductive portion.

[5] The conductive film according to the above [3] or [4], wherein the width of the wall portion is 5 μm or more and 500 μm or less.

[6] The dummy conductive portion containing conductive fibers and electrically insulated from the conductive portion is further provided, and the dummy conductive portion is filled between the wall portions different from the conductive portion. The conductive film according to any one of [3] to [5].

[7] A sensor comprising the conductive film according to any one of the above [3] to [6].

[8] A touch panel comprising the conductive film according to any one of the above [3] to [6].

[9] An image display device including the conductive film according to any one of the above [3] to [6] or the touch panel according to the above [8].

According to the present invention, it is possible to provide a conductive film capable of reducing costs and suppressing an electrical short circuit, a sensor provided with the conductive film, a touch panel, and an image display device.

FIG. 1 is a schematic configuration diagram of a conductive film according to an embodiment. FIG. 2 is a plan view of a part of the conductive film shown in FIG. FIG. 3 is an enlarged cross-sectional view of a part of the conductive film shown in FIG. FIG. 4 is a diagram for explaining the dimensions of each component of FIG. FIG. 5 is a plan view of a sample when measuring the electric resistance value. FIG. 6 is an enlarged view of a part of the sample of FIG. 7 (A) to 7 (C) are diagrams schematically showing the state of the folding test. FIG. 8 is a plan view of the conductive film after the folding test. 9 (A) and 9 (B) are diagrams schematically showing the manufacturing process of the conductive film according to the embodiment. 10 (A) to 10 (C) are views schematically showing the manufacturing process of the conductive film according to the embodiment. FIG. 11 is a schematic configuration diagram of an image display device according to an embodiment. FIG. 12 is a plan view of a part of the conductive film of the image display device of FIG.

Hereinafter, the conductive film, the sensor, the touch panel, and the image display device according to the embodiment of the present invention will be described with reference to the drawings. As used herein, the term "light transmissive" means the property of transmitting light. Further, "light transmission" does not necessarily have to be transparent, and may be translucent. FIG. 1 is a schematic configuration diagram of a conductive film according to the present embodiment, FIG. 2 is a plan view of a part of the conductive film shown in FIG. 1, and FIG. 3 is a conductive view shown in FIG. FIG. 4 is an enlarged cross-sectional view of a part of the sex film, and FIG. 4 is a diagram for explaining the dimensions of each component of FIG. 5 is a plan view of a sample for measuring an electric resistance value, FIG. 6 is an enlarged view of a part of the sample of FIG. 5, and FIGS. 7 (A) to 7 (C) are folded. It is a figure which showed the state of the test schematically, FIG. 8 is a plan view of the conductive film after a folding test, and FIG. 9 and FIG. 10 are schematics of the manufacturing process of the conductive film according to this embodiment. It is a figure shown as a target.

<<< Conductive film >>>
The conductive film 10 shown in FIG. 1 includes a light transmitting base material 11 and two or more electrically insulating wall portions 12 provided on the first surface 11A side of the light transmitting base material 11 and separated from each other. , The conductive portion 13 arranged on the first surface 11A side of the light transmissive base material 11 and filled between the wall portions 12, and the wall portion arranged on the first surface 11A side of the light transmissive base material 11 A dummy conductive portion 14 filled between the 12 and a light transmissive functional layer 15 provided on the second surface 11B side opposite to the first surface 11A of the light transmissive base material 11 is provided. However, the conductive film 10 may include the light-transmitting base material 11 and the conductive portion 13, and may not include the dummy conductive portion 14 and the light-transmitting functional layer 15. The "conductive portion" in the present specification is a portion that is electrically conductive and is actually energized, and the "dummy conductive portion" is a portion that is electrically conductive, but is actually It means a part that is not energized. The conductive portion 13 shown in FIG. 1 has a pattern having a predetermined shape (for example, a wiring pattern or the like).

Although the light-transmitting functional layer 15 is provided on the second surface 11B side of the light-transmitting base material 11, it may be provided between the light-transmitting base material 11 and the conductive portion 13, and the second It may be provided on both the surface 11B side and between the light transmitting base material 11 and the conductive portion 13. Further, in the conductive film 10 shown in FIG. 1, the wall portion 12, the conductive portion 13 and the dummy conductive portion 14 are provided only on one side, but the wall portion 12 and the conductive portion are provided on both side surfaces of the conductive film. 13 and a dummy conductive portion 14 may be provided.

The surface 10A of the conductive film 10 is composed of the surface 12A of the wall portion 12, the surface 13A of the conductive portion 13, and the surface 14A of the dummy conductive portion 14. In the present specification, since the surface of the conductive film is used to mean the surface of one side of the conductive film, the surface opposite to the surface of the conductive film is distinguished from the surface of the conductive film. Therefore, it shall be referred to as the back surface. The back surface 10B of the conductive film 10 is the front surface 15A of the light transmissive functional layer 15.

The haze value (total haze value) of the conductive film 10 is preferably 5% or less. When the haze value of the conductive film 10 is 5% or less, sufficient optical performance can be obtained. The haze value is a haze meter (for example, product name "HM-150", Murakami Color Technology Research Institute) in accordance with JIS K7136: 2000 under an environment where the temperature is 23 ± 5 ° C and the relative humidity is 30% or more and 70% or less. Can be measured using (manufactured by). The haze value is a value measured for the entire conductive film, and after cutting out to a size of 50 mm × 100 mm, the conductive portion side is the non-light source side in a state where there are no curls or wrinkles and no fingerprints or dust. (This is not the case when conductive parts are formed on both sides), and the arithmetic mean value obtained by measuring three times or more for one conductive film is used. In the present specification, "measuring three times" means not measuring the same place three times or more, but measuring three or more different places. By measuring the haze value at three or more different points of the cut out conductive film, it is considered that an approximate average value of the haze value of the entire in-plane of the conductive film can be obtained. As the number of measurements, it is preferable to measure 5 times, that is, 5 different points, and it is preferable to obtain an average value from the measured values of 3 points excluding the maximum value and the minimum value among them. If the conductive film cannot be cut out to the above size, for example, the HM-150 has an inlet opening of 20 mmφ at the time of measurement, so a sample having a diameter of 21 mm or more is required. Therefore, the conductive film may be appropriately cut out to a size of 22 mm × 22 mm or more. If the size of the conductive film is small, the measurement points are set to three points by shifting the light source spot little by little or changing the angle so as not to deviate. The haze value of the conductive film 10 is more preferably 3% or less, 2% or less, 1.5% or less, 1.2% or less, or 1.1% or less. The variation in the obtained haze value is within ± 10% regardless of whether the measurement target is as long as 1 m × 3000 m or the size of a 5-inch smartphone, and if it is within the above preferable range, , Low haze and low resistance value are more likely to be obtained. It is preferable that the haze value is the same as the above even in the entire laminated body in which a plurality of layers are overlapped, such as a touch panel on which a conductive film is mounted.

The total light transmittance of the conductive film 10 is preferably 80% or more. When the total light transmittance of the conductive film 10 is 80% or more, sufficient optical performance can be obtained. The total light transmittance is a haze meter (for example, product name "HM-150", Murakami) in accordance with JIS K7361-1: 1997 under an environment where the temperature is 23 ± 5 ° C and the relative humidity is 30% or more and 70% or less. It can be measured using (manufactured by Color Technology Laboratory). The total light transmittance of the conductive film 10 is more preferably 85% or more, 88% or more, or 89% or more. The total light transmittance is measured at 5 points and is the average value of the measured values at 3 points excluding the maximum value and the minimum value.

Even when the 180 ° folding test (folding test) is repeated 100,000 times so that the distance φ between the opposite sides of the conductive film 10 is 3 mm with respect to the conductive film 10, the conductivity before and after the folding test It is preferable that the electric resistance value ratio described later on the surface 13A of the conductive portion 13 of the sex film 10 is 3 or less. When the folding test is repeated 100,000 times on the conductive film, if the electric resistance value ratio on the surface of the conductive part of the conductive film before and after the folding test exceeds 3, the conductive film cracks or the like. Therefore, the flexibility of the conductive film becomes insufficient. Here, if the conductive film is cracked or the like in the folding test, the conductivity is lowered. Therefore, the electric resistance value on the surface of the conductive portion of the conductive film after the folding test is the conductive film before the folding test. It will be higher than the electric resistance value on the surface of the conductive part of. Therefore, by obtaining the electric resistance value ratio on the surface of the conductive portion of the conductive film before and after the folding test, it can be determined whether or not the conductive film is cracked or the like. The folding test may be performed so that the conductive film 10 is folded so that the conductive portion 13 is on the inside, or the conductive film 10 may be folded so that the conductive portion 13 is on the outside. However, in any case, it is preferable that the electric resistance value ratio on the surface 13A of the conductive portion 13 of the conductive film 10 before and after the folding test is 3 or less.

Even if the number of times of folding in the folding test is 200,000, 300,000, 500,000 or 1,000,000, the electric resistance value ratio of the conductive portion 13 of the conductive film 10 before and after the folding test is 3 or less. Is more preferable. As the number of times of folding increases, it becomes more difficult to reduce the electric resistance value ratio of the conductive part before and after the folding test to 3 or less. Therefore, the number of times of folding is 200,000, 300,000, 500,000 or 1,000,000. In the folding test of No. 1, the electric resistance value ratio of the conductive part 13 before and after the folding test is 3 or less, and in the folding test in which the number of times of folding is 100,000 times, the electric resistance value ratio of the conductive part 13 before and after the folding test is 3 or less. There is a remarkable technical difference from being. Further, the reason why the number of times of folding in the folding test is evaluated at least 100,000 times is as follows. For example, assuming that the conductive film is incorporated into a foldable smartphone, the frequency of folding (the frequency of opening and closing) becomes extremely high. Therefore, in the evaluation in which the number of times of folding in the folding test is, for example, 10,000 or 50,000, it may not be possible to evaluate at a practical level. Specifically, for example, assuming a person who always uses a smartphone, it is expected that the smartphone will be opened and closed 5 to 10 times even when commuting by train or bus in the morning, so at least one day alone. It is expected that the smartphone will be opened and closed 30 times. Therefore, assuming that the smartphone is opened and closed 30 times a day, the folding test in which the number of times of folding is 10,000 times is 30 times x 365 days = 10950 times, so that the test is assumed to be used for one year. That is, even if the result of the folding test in which the number of times of folding is 10,000 is good, there is a possibility that the conductive film may have folding habits or cracks after one year has passed. Therefore, the evaluation of 10,000 times of folding in the folding test means that only the level that cannot be used as a product can be confirmed, and the one that can be used but is insufficient is also good and cannot be evaluated. Therefore, in order to evaluate whether or not it is at a practical level, it is necessary to evaluate the number of times of folding in the folding test at least 100,000 times.

Regardless of whether the number of times of folding in the folding test is 100,000, 200,000, 300,000, 500,000 or 1,000,000, the electrical resistance of the conductive portion 13 of the conductive film 10 before and after the folding test. The value ratio is more preferably 1.5 or less.

In the folding test, the distance φ between the opposing sides of the conductive film 10 is 3 mm. However, from the viewpoint of reducing the thickness of the image display device, the distance φ between the facing sides of the conductive film 10 is Even when a folding test of folding 180 ° repeatedly 100,000 times so as to have a narrower range, specifically 2 mm or 1 mm, the electric resistance value ratio of the conductive portion 13 before and after the folding test is 3 or less. More preferably. Even if the number of times of folding is the same, as the interval φ becomes narrower, it becomes difficult to reduce the electric resistance value ratio of the conductive portion before and after the folding test to 3 or less. Therefore, the interval φ is 2 mm or 1 mm. It is technically that the electric resistance value ratio of the conductive part 13 before and after the folding test is 3 or less and that the electric resistance value ratio of the conductive part 13 before and after the folding test is 3 or less when the interval φ is 3 mm. There is a noticeable difference in.

When performing the folding test, first, a sample S1 having a predetermined size (for example, a rectangular shape of 125 mm in length × 50 mm in width) including the conductive portion 13 from an arbitrary portion of the conductive film 10 before the folding test. Is cut out (see FIG. 5). Here, it is assumed that the sample S1 is cut out so that the longitudinal direction of the sample S1 is the direction in which the conductive portion 13 extends (conduction direction). If the sample cannot be cut out to a size of 125 mm × 50 mm, the size may be any size that can be evaluated later after the folding test. For example, the sample is cut out into a rectangular shape having a size of 80 mm × 25 mm. May be good. After the sample S1 is cut out from the conductive film before the folding test, the electric resistance value of the surface 12A of the conductive portion 13 is measured in the sample S1 before the folding test. Specifically, as shown in FIG. 5, silver is used to prevent the measurement distance of the electric resistance value from fluctuating on both ends of the sample S1 in the longitudinal direction (for example, each portion of 10 mm in length × 50 mm in width). A paste (product name "DW-520H-14", manufactured by Toyobo Co., Ltd.) is applied and heated at 130 ° C. for 30 minutes to provide cured silver paste 21 at both ends on the sample S1. Then, the cured silver paste 21 is irradiated with laser light to remove a part of the silver paste 21 so that the dummy conductive portion 14 does not electrically conduct with the conductive portion 13 (see FIG. 6). The portion indicated by reference numeral 21A in FIG. 6 is a portion from which the silver paste 21 has been removed. In that state, the electric resistance value of each sample is measured using a tester (product name "Digital MΩ Hister 3454-11", manufactured by Hioki Electric Co., Ltd.). The distance between the silver pastes 21 (the distance of the portion where the silver paste 17 is not provided) is the measurement distance of the electric resistance value in the sample S1 (for example, 100 mm), but this measurement distance is constant between the samples S1. And. When measuring the electric resistance value, the probe terminals of the tester are brought into contact with the portions of the cured silver paste 21 provided at both ends that are in contact with the conductive portion 13. The measurement of the electric resistance value of the conductive portion 13 shall be performed in an environment where the temperature is 23 ± 5 ° C. and the relative humidity is 30% or more and 70% or less. In the sample before the folding test, after measuring the electric resistance value of the conductive portion 13, the folding test is performed on the sample S1.

The folding test is performed as follows. As shown in FIG. 7A, in the folding test, first, the side portion S1a of the selected sample S1 and the side portion S1b facing the side portion S1a are arranged in parallel with each other in a folding durability tester (for example,). , Product name "U-shaped expansion and contraction tester DLDMLH-FS", manufactured by Yuasa System Co., Ltd., IEC62715-6-1 compliant). Fixing by the fixing portion 25 is performed by holding a portion of the sample S1 having a length of about 10 mm on one side in the longitudinal direction of the sample S1. However, when the sample S1 is further smaller than the above size, if the portion of the sample S1 required for this fixing is up to about 20 mm, the measurement can be performed by attaching the sample S1 to the fixing portion 25 with a tape. (That is, the minimum sample is 60 mm × 25 mm) Further, as shown in FIG. 7 (A), the fixed portion 25 can be slidably moved in the horizontal direction. It should be noted that the above device is preferable because it is possible to evaluate the durability against a bending load without generating tension or friction on the sample, unlike the conventional method of winding a sample around a rod.

Next, as shown in FIG. 7B, by moving the fixing portions 25 so as to be close to each other, the central portion S1c of the sample S1 is deformed so as to be folded, and further, as shown in FIG. 7C. After moving the fixing portion 25 to a position where the distance φ between the two opposing side portions S1a and S1b fixed by the fixing portion 25 of the sample S1 is 3 mm, the fixing portion 25 is moved in the opposite direction to sample. The deformation of S1 is eliminated.

By moving the fixing portion 25 as shown in FIGS. 7A to 7C, the sample S1 can be folded 180 ° at the central portion S1c. Further, by preventing the bent portion S1d of the sample S1 from protruding from the lower end of the fixed portion 25, performing a folding test under the following conditions, and controlling the interval when the fixed portion 25 is closest to the fixed portion 25 to 3 mm. The distance φ between the two opposing sides S1a and S1b of the sample S1 can be set to 3 mm. In this case, the outer diameter of the bent portion S1d is regarded as 3 mm. Since the thickness of the sample S1 is sufficiently smaller than the interval (3 mm) of the fixing portions 25, the result of the folding test of the sample S is considered not to be affected by the difference in the thickness of the sample S1. be able to.
(Folding conditions)
・ Round trip speed: 80 rpm (revolutions per minute)
・ Test stroke: 60 mm
・ Bending angle: 180 °

After the folding test, in the sample S1 after the folding test, the electric resistance value of the surface of the conductive portion is measured in the same manner as in the sample S1 before the folding test. Then, the ratio of the electric resistance value of the sample S after the folding test to the electric resistance value of the selected sample S before the folding test (the electric resistance value of the sample after the selected folding test / the electric resistance of the sample before the folding test). Value) is calculated. The electrical resistance value ratio is the arithmetic mean value of the values obtained by measuring three times.

When the above-mentioned folding test is performed on the conductive film, even if the electric resistance value ratio of the conductive part of the conductive film before and after the folding test is 3 or less, a bending habit occurs at the bent part and microcracks occur. As a result, there is a risk of poor appearance, specifically, delamination (poor adhesion) starting from a clouding phenomenon or microcracks. It is considered that one of the causes of the cloudiness phenomenon is that the crystal state of the organic compound, which is the material of any layer of the conductive film, changes. When poor adhesion occurs locally, moisture may accumulate in the delamination portion or air may enter the delamination portion due to changes in temperature and humidity, which may increase cloudiness. It should be noted that microcracks hardly occur in the case of only the light-transmitting base material or only the laminate in which some functional layer is provided on the light-transmitting base material. That is, the origin of the occurrence is unknown, but it is presumed that the conductive portion containing the conductive fiber is a factor. In recent years, displays are not just flat surfaces, but are being folded, curved, and various three-dimensional designs are increasing. Therefore, suppression of bending habits and microcracks at the bent portion is extremely important for use as an image display device. For this reason, the conductive film 10 preferably has flexibility. The term "flexibility" as used herein means that, before and after the folding test, not only the electrical resistance value ratio of the conductive portion is 3 or less, but also folding habits and microcracks are not confirmed. Therefore, the "flexibility" in the present specification is different from the flexibility that only requires that the electric resistance value ratio of the conductive portion is 3 or less before and after the folding test.

The above fold habits shall be observed visually, but when observing fold habits, the bent portion shall be evenly observed by transmitted light and reflected light in a bright room (800 lux to 2000 lux) with white illumination. In both cases, both the inner part and the outer part of the bent part when folded shall be observed. The observation of the bending habit shall be carried out in an environment where the temperature is 23 ± 5 ° C. and the relative humidity is 30% or more and 70% or less.

The observation of the microcracks shall be performed with a digital microscope (digital microscope). Examples of the digital microscope include VHX-5000 manufactured by KEYENCE CORPORATION. For microcracks, ring illumination is selected as the illumination for the digital microscope, and observation is made in the dark field and reflected light. Specifically, first, the sample after the folding test is slowly spread, and the sample is fixed to the stage of the microscope with tape. At this time, if the crease is strong, the observation area should be as flat as possible. However, the planned observation area (bent part) near the center of the sample should not be touched by hand and no force should be applied. Then, it is assumed that both the inner part and the outer part when folded are observed. The observation of the microcracks shall be performed in an environment where the temperature is 23 ± 5 ° C. and the relative humidity is 30% or more and 70% or less.

In the observation of the folding habit and the microcrack, the sample before the folding test is installed in the fixed part of the durability tester and folded once so that the position to be observed can be easily grasped. As shown, it is preferable to attach a mark A1 indicating the bent portion to both ends S1d ₁ located in the direction orthogonal to the folding direction FD in the bent portion S1d with an oil-based pen or the like. Further, in the case of a sample in which no folding habit is observed after the folding test, in order to prevent the observation position of the sample from becoming unclear, the bent portion S1d at both ends S1d _{1 with the} sample removed from the durability tester after the folding test. The line A2 (dotted line in FIG. 8) connecting the marks A1 may be drawn with an oil-based pen or the like. Then, in observing the bending habit, the entire bent portion S1d, which is a region formed by the mark A1 of both ends S1d ₁ of the bent portion S1d and the line A2 connecting the marks A1 to each other, is visually observed. In observing the microcracks, the position of the scope is adjusted so that the center of the scope visual field range (the range surrounded by the alternate long and short dash line in FIG. 8) is the center of the bent portion S1d. Be careful not to mark the mark with an oil-based pen in the sample area required for actual measurement.

Further, when the folding test is performed on the conductive film, the adhesion between the light-transmitting base material and the light-transmitting functional layer may decrease. Therefore, when the vicinity of the interface between the light-transmitting base material 11 and the light-transmitting functional layer 15 is observed with a digital microscope in the bent portion of the conductive film after the folding test, the light-transmitting base material 11 It is preferable that no peeling or the like is observed near the interface between the light transmissive functional layer 15 and the light transmissive functional layer 15. Examples of the digital microscope include VHX-5000 manufactured by KEYENCE CORPORATION.

When another film is provided on the conductive film via an adhesive layer or an adhesive layer, the haze value or total light transmittance is measured after peeling off the other film together with the adhesive layer or the adhesive layer. In addition, a folding test shall be conducted. The peeling of the other film can be performed, for example, as follows. First, heat the laminate with another film attached to the conductive film via an adhesive layer or adhesive layer with a dryer, insert the cutting edge of the cutter into the part that seems to be the interface between the conductive film and the other film, and slowly And peel off. By repeating such heating and peeling, the adhesive layer, the adhesive layer and other films can be peeled off. Even if such a peeling step is performed, it does not have a great influence on the measurement of the haze value and the like and the folding test.

Further, as described above, when measuring the haze value and total light transmittance of the conductive film 10, or when performing a folding test on the conductive film 10, the conductive film 10 is cut out to each of the above sizes. It is necessary, but when the size of the conductive film 10 is large (for example, in the case of a long roll such as a roll), A4 size (210 mm × 297 mm) or A5 size (148 mm × 210 mm) from an arbitrary position. After cutting out, it shall be cut out to the size of each measurement item. Further, when the conductive film 10 is in the form of a roll, it is not an ineffective region including both ends extending along the longitudinal direction of the roll while feeding out a predetermined length from the roll of the conductive film 10. It shall be cut out from the effective area near the center where the quality is stable. Further, when measuring the haze value and total light transmittance of the conductive film 10, or when performing a folding test on the conductive film 10, the measurement is performed using the above device, but even if it is not the above device, it is a successor model. It may be measured by a similar device such as.

The thickness of the conductive film 10 is not particularly limited, but can be 500 μm or less. The lower limit of the thickness of the conductive film 10 is more preferably 5 μm or more, 10 μm or more, or 20 μm or more from the viewpoint of handleability and the like. The upper limit of the thickness of the conductive film 10 is 250 μm or less and 100 μm or less from the viewpoint of thinning, and more preferably 78 μm or less, particularly 45 μm or less when flexibility is important. Therefore, when flexibility is important, the thickness of the conductive film 10 is preferably 5 μm or more and 78 μm or less, and more preferably 28 μm or less and 20 μm or less. The thickness of the conductive film is randomly selected from 10 cross-sectional photographs of the conductive film taken using a transmission electron microscope (TEM), a scanning transmission electron microscope (STEM), or a scanning electron microscope (SEM). The average value of the thicknesses of 8 points excluding the maximum value and the minimum value among the measured thicknesses of 10 points. The conductive film generally has uneven thickness. In the present invention, since the conductive film is used for optical purposes, the thickness unevenness is preferably ± 2 μm or less, and more preferably ± 1 μm or less.

When the thickness of the conductive film is measured using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM), it can be measured by the same method as the method for measuring the thickness of the conductive portion. However, the magnification when taking a cross-sectional photograph of the conductive film is 100 to 20,000 times. When measuring the thickness of a conductive film using a scanning electron microscope (SEM), the cross section of the conductive film can be obtained by using an ultramicrotome (product name "Ultramicrotome EM UC7", manufactured by Leica Microsystems, Inc.) or the like. It is good. The measurement sample for measurement by TEM or STEM is set to a delivery thickness of 100 nm by using the above-mentioned ultramicrotome to prepare an ultrathin section. The prepared ultrathin section is collected by a mesh with a collodion membrane (150) and used as a measurement sample. At the time of ultra-microtome cutting, a pretreatment that facilitates cutting may be performed, such as embedding a measurement sample in resin.

The use of the conductive film 10 is not particularly limited, and may be used, for example, in various applications in which a transparent conductive film is used (for example, a sensor application). Further, the conductive film of the present invention is used for image display devices (including smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PIDs), in-vehicle displays, etc.) and in-vehicle (trains and vehicles). Suitable for applications (including all types of vehicles, such as vehicle construction machines). When the conductive film is used as a sensor for in-vehicle use, for example, a sensor arranged in a portion touched by a person such as a steering wheel or a seat can be mentioned. The conductive film is also preferable for applications that require flexibility such as foldable and rollable. Further, it may be used for electric appliances and windows used in houses and cars (including all cars such as trains and vehicle construction machines). In particular, the conductive film of the present invention can be suitably used in a portion where transparency is important. Further, the conductive film of the present invention can be suitably used not only for technical viewpoints such as transparency, but also for electric appliances that are required to have designability and designability. Specific applications of conductive films other than image display devices include, for example, defrosters, antennas, solar cells, audio systems, speakers, electric fans, electronic blackboards, carrier films for semiconductors, and the like. The shape of the conductive film when used is appropriately designed according to the intended use, and is not particularly limited, but may be, for example, a curved surface.

The conductive film 10 may be cut to a desired size, but may be in a roll shape. If the conductive film is in the form of a roll, it may be cut to a desired size at this stage. When the conductive film 10 is cut to a desired size, the size of the conductive film is not particularly limited and is appropriately determined according to the size of the display surface of the image display device. Specifically, the size of the conductive film may be, for example, 5 inches or more and 500 inches or less. As used herein, the term "inch" means the length of the diagonal line when the conductive film is square, the diameter when it is circular, and short when it is elliptical. It shall mean the average value of the sum of the diameter and the major axis. Here, when the conductive film has a quadrangular shape, the aspect ratio of the conductive film when determining the inch is not particularly limited as long as there is no problem in the display screen of the image display device. For example, vertical: horizontal = 1: 1, 4: 3, 16:10, 16: 9, 2: 1 and the like. However, the aspect ratio is not limited to this, especially in in-vehicle applications and digital signage, which are rich in design. When the size of the conductive film 10 is large, it is cut out from an arbitrary position to a size that is easy to handle, such as A4 size (210 mm × 297 mm) or A5 size (148 mm × 210 mm), and then the size of each measurement item. It shall be cut out. For example, when the conductive film 10 is in the form of a roll, in an ineffective region including both ends extending along the longitudinal direction of the roll while paying out a predetermined length from the roll of the conductive film 10. It shall be cut out to the desired size from the effective region near the central part where the quality is stable.

<< Light-transmitting substrate >>
The light-transmitting base material 11 is not particularly limited as long as it has light-transparency. For example, as a constituent material of the light-transmitting base material 11, a base material containing a resin having light-transmitting property can be mentioned. Such a resin is not particularly limited as long as it has light transmissivity, and is, for example, a polyolefin resin, a polycarbonate resin, a polyacrylate resin, a polyester resin, an aromatic polyether ketone resin, or a polyether sulfone. Examples thereof include a based resin, a polyimide resin, a polyamide resin, a polyamide imide resin, and a mixture of two or more kinds of these resins. Since the light-transmitting base material touches the coating device when coating the light-transmitting functional layer or the like, it is easily scratched, but the light-transmitting base material made of polyester resin is scratched even if it touches the coating device. Since it is difficult to adhere, it is possible to suppress an increase in haze value, and it is also superior in heat resistance, barrier property, and water resistance to a light transmissive base material made of a light transmissive resin other than polyester resin. Of these, polyester-based resins are preferable.

When a foldable conductive film is obtained as the conductive film, the resin constituting the light-transmitting base material has good flexibility, so that it is a polyimide resin, a polyamide-imide resin, or a polyamide resin. , Polyester resin or a mixture thereof is preferably used. Further, among these, not only has excellent flexibility, but also has excellent hardness and transparency, and also has excellent heat resistance, and by firing, further excellent hardness and transparency are imparted. From the viewpoint that it can also be used, a polyimide resin, a polyamide resin, or a mixture thereof is preferable.

Examples of the polyolefin-based resin include resins containing at least one component such as polyethylene, polypropylene, and cycloolefin polymer-based resins. Examples of the cycloolefin polymer resin include those having a norbornene skeleton.

Examples of the polycarbonate-based resin include aromatic polycarbonate resins based on bisphenols (bisphenol A and the like), aliphatic polycarbonate resins such as diethylene glycol bisallyl carbonate and the like.

Examples of the polyacrylate-based resin include a poly (meth) methyl acrylate base material, a poly (meth) ethyl acrylate base material, and a methyl (meth) acrylate- (meth) butyl acrylate copolymer.

Examples of the polyester-based resin include resins containing at least one of polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN) as constituents. Among these, PET is preferable from the following viewpoints.

Examples of the aromatic polyetherketone-based resin include polyetheretherketone (PEEK) and the like.

The polyimide resin may contain a polyamide structure as a part thereof. Examples of the polyamide structure that may be contained include a polyamide-imide structure containing a tricarboxylic acid residue such as trimellitic anhydride and a polyamide structure containing a dicarboxylic acid residue such as terephthalic acid. Polyamide-based resin is a concept that includes not only aliphatic polyamide but also aromatic polyamide (aramid). Specifically, examples of the polyimide-based resin include compounds having structures represented by the following chemical formulas (1) and (2). In the following chemical formula, n is a repeating unit and represents an integer of 2 or more. Among the compounds represented by the following chemical formulas (1) and (2), the compound represented by the chemical formula (1) is preferable because it has a low phase difference and high transparency.

The thickness of the light-transmitting base material 11 is not particularly limited, but can be 500 μm or less, and the lower limit of the thickness of the light-transmitting base material 11 is 3 μm or more and 5 μm or more and 10 μm or more from the viewpoint of handleability and the like. , Or more preferably 20 μm or more. The upper limit of the thickness of the light transmissive base material 11 is 250 μm or less, 100 μm or less, 80 μm or less, 50 μm or less from the viewpoint of thinning, and 35 μm or less, particularly 18 μm or less when flexibility is important. More preferred. The thickness of the light-transmitting substrate is randomly selected from a cross-sectional photograph of the light-transmitting substrate taken using a transmission electron microscope (TEM), a scanning transmission electron microscope (STEM), or a scanning electron microscope (SEM). The thickness at 10 points is measured, and the average value of the thicknesses at 8 points excluding the maximum value and the minimum value among the measured thicknesses at 10 points. The light-transmitting base material generally has uneven thickness. In the present invention, since the light-transmitting base material is used for optics, the thickness unevenness is preferably ± 2 μm or less, more preferably ± 1 μm or less.

When the thickness of the light transmissive substrate is measured using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM), it can be measured by the same method as the method for measuring the thickness of the conductive portion. However, the magnification when taking a cross-sectional photograph of the light-transmitting base material is 100 to 20,000 times. When measuring the thickness of a light-transmitting substrate using a scanning electron microscope (SEM), the cross section of the light-transmitting substrate is an ultramicrotome (product name "Ultramicrotome EM UC7", manufactured by Leica Microsystems), etc. It is good to obtain using. The measurement sample for TEM or STEM is set to a delivery thickness of 100 nm by using the above-mentioned ultramicrotome, and an ultrathin section is prepared. The prepared ultrathin section is collected by a mesh with a collodion membrane (150) and used as a measurement sample for TEM or STEM. At the time of ultra-microtome cutting, a pretreatment for easy cutting such as embedding a sample in resin may be performed.

Conductive fibers such as silver nanowires themselves are suitable for flexibility, for example, but the light-transmitting base material and functional layer (excluding the conductive parts) for laminating conductive parts containing conductive fibers are thick. When folded, the light-transmitting base material and the functional layer at the bent portion are cracked, and the cracks may cause the conductive fibers to break, and the light-transmitting base material and the functional layer at the bent portion may be broken. Folding habits and microcracks may occur. In addition to not being able to obtain the desired resistance value due to the above-mentioned disconnection, there is a risk that appearance defects, specifically, white turbidity and poor adhesion due to cracks may occur. For this reason, when the conductive film is used for flexible applications, the thickness of the light-transmitting base material and the functional layer is controlled, and the adhesion between the layers (adhesion due to chemical bonds influenced by the material and cracks do not occur). Close contact) is important. In particular, when the light-transmitting base material 11 contains a polyester-based resin or a polyimide-based resin, the resistance to cracking changes depending on the thickness, so it is important to control the thickness of the light-transmitting base material.

When the light-transmitting base material 11 contains, for example, a polyester-based resin, the thickness of the light-transmitting base material 11 is preferably 45 μm or less. When the thickness of the light-transmitting base material 11 is 45 μm or less, cracking of the light-transmitting base material 11 at the bent portion can be suppressed at the time of folding, and a clouding phenomenon at the bent portion can be suppressed. In this case, the upper limit of the thickness of the light-transmitting base material 11 is preferably 35 μm or less, 29 μm or less, and particularly preferably 18 μm or less. Further, the lower limit of the thickness of the light transmissive base material 11 in this case is preferably 5 μm or more from the viewpoint of handleability and the like.

When the light-transmitting base material 11 contains, for example, a polyimide resin, a polyamide-based resin, a polyamide-imide-based resin, or a mixture thereof, cracking of the light-transmitting base material 11 at the time of folding is suppressed, optical characteristics, and the like. From the viewpoint of mechanical properties, the thickness of the light-transmitting substrate 11 is preferably thin, specifically, 75 μm or less. In this case, the upper limit of the thickness of the light-transmitting base material 11 is preferably 70 μm or less, 50 μm or less, 35 μm or less, 29 μm or less, and particularly preferably 20 μm or less and 18 μm or less. Further, the lower limit of the thickness of the light transmissive base material 11 in this case is preferably 5 μm or more from the viewpoint of handleability and the like.

When the thickness of each of the above-mentioned light-transmitting substrates is 35 μm or less, particularly when it is 5 μm or more and 20 μm or less or 18 μm or less, it is preferable to attach a protective film at the time of manufacture because the processing suitability is improved.

The light-transmitting base material 11 may be subjected to a physical treatment such as a corona discharge treatment or an oxidation treatment on the surface in order to improve the adhesiveness. Further, the light transmissive base material 11 is applied to at least one surface side in order to improve the adhesiveness with the other layer, to prevent sticking at the time of winding, and / or to form another layer. It may have a base layer for suppressing the repelling of the liquid. However, when a conductive portion is formed on the surface of the base layer using a conductive fiber-containing composition containing conductive fibers and a dispersion medium, the dispersion medium penetrates into the base layer, although the degree varies depending on the type of dispersion system. As a result, conductive fibers may also enter the base layer and the electric resistance value may increase. Therefore, the conductive portion of the light-transmitting base material does not have a base layer, and the conductive portion is a light-transmitting group. It is preferably provided directly on the material. In the present specification, the base layer existing on at least one surface side of the light-transmitting base material and in contact with the light-transmitting base material shall form a part of the light-transmitting base material, and has a light-transmitting function. It shall not be included in the layer.

The base layer is a layer having a function of improving adhesion with other layers, a function of preventing sticking at the time of winding, and / or a function of suppressing repelling of a coating liquid forming the other layer. Whether or not the light-transmitting substrate has an underlayer is determined by using a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), or a transmission electron microscope (TEM) from 10 to 500,000. Confirmed by observing the cross section around the interface between the light-transmitting base material and the conductive part and around the interface between the light-transmitting base material and the light-transmitting functional layer at double (preferably 25,000 to 50,000 times). can do. Since the base layer may contain particles such as a lubricant to prevent sticking during winding, even if the particles are present between the light-transmitting base material and the light-transmitting functional layer, the particles may be present. It can be determined that this layer is the base layer.

The film thickness of the base layer is preferably 10 nm or more and 1 μm or less. When the film thickness of the base layer is 10 nm or more, the function as the base layer is fully exhibited, and when the film thickness of the base layer is 1 μm or less, there is no possibility of optical influence. The thickness of the base layer is 1000 to 500,000 times (preferably 25,000 to 5 times) using a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), or a transmission electron microscope (TEM). The thickness at 10 points is randomly measured from the cross-sectional photograph of the base layer taken at 10,000 times), and the thickness is taken as the arithmetic average value of the measured 10 points. The lower limit of the film thickness of the base layer is more preferably 30 nm or more, and the upper limit is more preferably 150 nm or less. The film thickness of the base layer can also be measured by the same method as the film thickness of the conductive portion 13. When taking a cross-sectional photograph by SEM, TEM, or STEM, it is preferable to prepare a measurement sample using an ultramicrotome as described above.

The base layer contains, for example, an anchor agent and a primer agent. Examples of the anchor agent and primer agent include polyurethane resin, polyester resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer, acrylic resin, polyvinyl alcohol resin, polyvinyl acetal resin, and ethylene. Polymers of vinyl acetate or acrylic acid, copolymers of ethylene and styrene and / or butadiene, thermoplastic resins such as olefin resins and / or modified resins thereof, polymers of ionizing radiation polymerizable compounds, And at least one of a polymer of a heat-polymerizable compound and the like can be used.

As described above, the base layer may contain particles such as a lubricant to prevent sticking during winding. Examples of the particles include silica particles.

<< Light-transmitting functional layer >>
The light-transmitting functional layer 15 is provided on the second surface 11B side of the light-transmitting base material 11. The "light-transmitting functional layer" in the present specification is a layer having light-transmitting property and intended to exert some function in a conductive film. Specifically, examples of the light transmissive functional layer include a layer for exerting a hard coat function, a refractive index adjusting function, and / or a color tint adjusting function. The light transmissive functional layer may be not only a single layer but also a laminated layer of two or more layers. When two or more light-transmitting functional layers are laminated, the functions of the respective layers may be the same, but may be different. In the present embodiment, the case where the light transmissive functional layer 15 is a layer that exerts a hard coat function, that is, a hard coat layer will be described. When obtaining flexibility, the light transmissive functional layer may be a layer other than the hard coat layer. In that case, the light-transmitting functional layer may be less than the pencil hardness and the cross-sectional hardness shown below. Even in such a case, the mechanical orientation strength is higher than that of the light-transmitting base material alone, so that it functions as a hard coat layer.

The light transmissive functional layer 15 is a layer having a hardness of "H" or higher in the pencil hardness test (4.9 N load) specified in JIS K5600-5-4: 1999. By setting the pencil hardness to "H" or higher, the conductive film 10 becomes hard and the durability can be improved. From the viewpoint of toughness of the light transmissive functional layer and prevention of curling, the upper limit of the pencil hardness of the surface 10A of the conductive film 10 is preferably about 2H to 4H.

Indentation hardness of the light-transmissive functional layer 15 _{(H IT)} is preferably at least 100 MPa. When flexibility is of paramount importance, it is preferably less than 20-100 MPa. The lower limit of the indentation hardness of the light transmissive functional layer 15 may be 200 MPa or more or 300 MPa or more, and the upper limit is to prevent microcracks, and the light transmissive functional layer, the light transmissive base material, and the conductive portion. From the viewpoint of maintaining the adhesion at the interface of each layer, it may be 800 MPa or less. By setting such a lower limit and an upper limit, the flexibility of the conductive portion itself due to conductive fibers or the like can be maintained. Further, in a structure having a conductive portion, in order to put it into practical use, it is necessary that the resistance value, the physical characteristics, and the optical characteristics are almost the same as those before the test even after the folding test. Further, the light transmissive functional layer is effective as a layer having a role of preventing scratches during processing. For this reason, in order to utilize the flexibility of conductive fibers such as silver nanowires and to obtain the above-mentioned physical characteristics for practical use, it is preferable that they are within the above-mentioned numerical range. Although it depends on the application, it is preferable that the light transmitting functional layer is provided on both side surfaces of the light transmitting base material rather than the case where the light transmitting functional layer is provided only on one surface side of the light transmitting base material. ..

The "indentation hardness" in the present specification is a value obtained from a load-displacement curve from indenter load to unloading. Measurement of the indentation hardness _{(H IT)} is under an environment of temperature 23 ± 5 ° C. and a relative humidity of 30% to 70% or less, using a Hysitron (Heidi Tron) manufactured by "TI950 TriboIndenter" measurement samples Assumed to be performed. The measurement sample may be prepared by the same method as the sample prepared at the time of taking the cross-sectional photograph by the SEM described above. When the thickness of the light transmissive functional layer 15 is thin, it is preferable to sufficiently increase the measurement area by using an oblique cutting device such as a surface / interface cutting test device (Surface And Interface Cutting Analysis System: SAICAS). Normally, cross-section analysis analyzes the surface (vertical cross-section) of a sample cut perpendicular to the surface, but if the sample has a multi-layer structure and each layer is thin, or if a large analysis area is required, a specific layer is used. Is difficult to selectively analyze. However, when the cross section is produced by diagonal cutting, the sample surface can be exposed more widely than the vertical cross section. For example, when a slope of 10 ° with respect to a horizontal plane is prepared, the sample plane is slightly wider than the vertical cross section by a little less than 6 times. Therefore, by producing a cross section by diagonal cutting with SAICAS, it is possible to analyze a sample that is difficult to analyze with a vertical cross section. Next, in the cross section of the obtained measurement sample, a flat part was searched, and in this flat part, the Berkovich indenter (Berkovich) indenter (Berkovich) indenter at a speed of 10 nm / sec so that the maximum indentation displacement was 100 nm in the displacement-based measurement. A triangular pyramid (TI-0039 manufactured by BRUKER Co., Ltd.) is pushed vertically into the light transmissive functional layer 15 while applying a load from a displacement of 0 nm to a displacement of 100 nm in 10 seconds. Here, the Berkovich indenter is light-transmitting from the interface between the light-transmitting base material and the light-transmitting functional layer in order to avoid the influence of the light-transmitting base material and the influence of the side edge of the light-transmitting functional layer. It is assumed that the light-transmitting functional layer is pushed into the portion of the light-transmitting functional layer 500 nm away from the center side of the functional layer and 500 nm or more from both side ends of the light-transmitting functional layer to the center side of the light-transmitting functional layer. After that, it is held at a displacement of 100 nm for 5 seconds, and then unloaded from the displacement of 100 nm to the displacement of 0 nm in 10 seconds. Then, the pushing depth h (nm) corresponding to the pushing load F (N) at this time is continuously measured, and a load-displacement curve is created. From the created load-displacement curve, the indentation hardness is calculated, the maximum pushing load F _max (N) is calculated as shown in the following mathematical formula (1), and the contact projection area _Ap (contact projection area Ap where the indenter and the light transmissive functional layer 15 are in contact) Calculated by the value divided by mm ² ). The indentation hardness is the arithmetic mean value of the measured values of 8 points obtained by subtracting the maximum value and the minimum value from the values obtained by measuring 10 points. A _p by using a fused quartz standard samples, the contact projected area obtained by correcting the indenter tip curvature in Oliver-Pharr method.
H _IT = F _max / _Ap ... (1)

In order to control the physical characteristics of the conductive film having the light transmissive functional layer, it is conceivable to measure the elastic coefficient of the light transmissive functional layer itself, but the light transmissive functional layer having a three-dimensional crosslinked structure Since is thin and brittle, it is difficult to form a film with a single layer, and it is difficult to measure the elastic characteristics and the like with the light-transmitting functional layer as a single layer. Therefore, in the above, the evaluation is performed by measuring the hardness by the nanoindentation method. By this method, it is possible to measure the physical properties of the film itself even if it is a thin film polymer material regardless of the influence of the light-transmitting base material, and from the load displacement curve of the elastic / plastic deformable substance, the mathematical formula (as described above) Hardness can be analyzed by 1).

The film thickness of the light transmissive functional layer 15 is preferably 0.2 μm or more and 15 μm or less. If the film thickness of the light transmissive functional layer 15 is 0.2 μm or more, a desired hardness can be obtained, and if the film thickness of the light transmissive functional layer 15 is 15 μm or less, the conductive film 10 is thin. Can be achieved. From the viewpoint of hard coatability, the lower limit of the film thickness of the light transmissive functional layer 15 is more preferably 0.3 μm or more, 0.5 μm or more, or 0.7 μm or more. Further, the upper limit of the film thickness of the light transmissive functional layer 15 is more preferably 12 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, or 2 μm or less from the viewpoint of thinning the light transmissive functional layer 15. .. However, when the light transmissive functional layer is laminated on both sides of the light transmissive base material, it is preferably thinner than the film thickness of the light transmissive functional layer 15 described above. In this case, the film thickness of each light-transmitting functional layer is preferably 3 μm or less, 1.5 μm or less, and 1 μm or less, particularly in the bent portion, in order to reduce the thickness and obtain good flexibility. When φ is less than 2 mm, for example, φ is less than 0.1 to 1 mm, the film thickness of each light transmissive functional layer is 0.8 μm or less, 0.7 μm or less, and further 0.5 μm or less. That is good. As will be described later, the film thickness of the conductive portion 13 is preferably 300 nm or less, but when the conductive layer is laminated on the light transmissive functional layer, the conductive layer is mixed in the light transmissive functional layer. It may end up. In such a case, the interface between the functional layer and the conductive layer may not be discriminated. In this case, the preferable film thickness of the light-transmitting functional layer may be the total film thickness of the light-transmitting functional layer and the conductive layer.

The thickness of the light transmissive functional layer is randomly selected from a cross-sectional photograph of the light transmissive functional layer taken using a transmission electron microscope (TEM), a scanning transmission electron microscope (STEM), or a scanning electron microscope (SEM). The thickness at 10 points is measured, and the average value of the thicknesses at 8 points excluding the maximum value and the minimum value among the measured thicknesses at 10 points. The light transmissive functional layer generally has uneven thickness. In the present invention, since the light transmissive functional layer is used for optics, the thickness unevenness is preferably ± 10% or less on average thickness, and more preferably ± 5% or less on average thickness.

When the thickness of the light transmissive substrate is measured using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM), it can be measured by the same method as the method for measuring the thickness of the conductive portion. However, the magnification when taking a cross-sectional photograph of the light-transmitting base material is 100 to 20,000 times. When measuring the thickness of a light-transmitting substrate using a scanning electron microscope (SEM), the cross section of the light-transmitting substrate is an ultramicrotome (product name "Ultramicrotome EM UC7", manufactured by Leica Microsystems), etc. It is good to obtain using. The measurement sample for TEM or STEM is set to a delivery thickness of 100 nm by using the above-mentioned ultramicrotome, and an ultrathin section is prepared. The prepared ultrathin section is collected by a mesh with a collodion membrane (150) and used as a measurement sample for TEM or STEM. At the time of ultra-microtome cutting, a pretreatment that facilitates cutting may be performed, such as embedding a measurement sample in resin.

If the thickness of the light-transmitting base material 11 is thin, it becomes difficult to pass through the line, it becomes easy to avoid it, and it becomes difficult to handle it in the process such as being easily scratched. Therefore, the conductive film 10 is at least the light-transmitting base material 11. It is preferable to provide the light transmissive functional layer 15 on one side of the above. When the conductive film 10 is used in a flexible application, it is important that the light transmissive functional layer 15 is brought into close contact with the light transmissive base material 11 and follows the light transmissive base material 11 when folded. In order to form the light-transmitting functional layer 15 that adheres to the light-transmitting base material 11 and can follow the light-transmitting base material 11 when folded, the light is transmitted with respect to the thickness of the light-transmitting base material 11. The balance of the film thickness of the sexual functional layer 15 is also important.

The light-transmitting functional layer 15 can be composed of at least a light-transmitting resin. The light-transmitting functional layer 15 may contain inorganic particles, organic particles, and a leveling agent in addition to the light-transmitting resin.

<Light transmissive resin>
Examples of the light-transmitting resin in the light-transmitting functional layer 15 include those containing a polymer (cured product, crosslinked product) of a polymerizable compound. The light-transmitting resin may contain a solvent-drying resin in addition to a polymer of a polymerizable compound. Examples of the polymerizable compound include an ionizing radiation polymerizable compound and / or a thermopolymerizable compound. Among these, an ionizing radiation polymerizable compound is preferable as the polymerizable compound because the curing rate is high and the design is easy.

The ionizing radiation polymerizable compound has at least one ionizing radiation polymerizable functional group in one molecule. The "ionizing radiation-polymerizable functional group" in the present specification is a functional group capable of polymerizing by ionizing radiation irradiation. Examples of the ionizing radiation polymerizable functional group include ethylenically unsaturated groups such as (meth) acryloyl group, vinyl group and allyl group. The "(meth) acryloyl group" means to include both the "acryloyl group" and the "methacryloyl group". Further, examples of the ionizing radiation emitted when polymerizing the ionizing radiation polymerizable compound include visible light, ultraviolet rays, X-rays, electron beams, α rays, β rays, and γ rays.

Examples of the ionizing radiation-polymerizable compound include an ionizing radiation-polymerizable monomer, an ionizing radiation-polymerizable oligomer, and an ionizing radiation-polymerizable prepolymer, which can be appropriately adjusted and used. As the ionizing radiation-polymerizable compound, a combination of an ionizing radiation-polymerizable monomer and an ionizing radiation-polymerizable oligomer or an ionizing radiation-polymerizable prepolymer is preferable.

Examples of the ionizing radiation polymerizable monomer include a monomer containing a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, and ethylene glycol di (meth) acrylate. , Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethyl propantri (meth) acrylate, trimethylol ethanetri (meth) ) Acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerol (meth) acrylate (Meta) acrylic acid esters such as and the like.

As the ionizing radiation polymerizable oligomer, a polyfunctional oligomer having two or more functional groups is preferable, and a polyfunctional oligomer having three or more (trifunctional) ionizing radiation polymerizable functional groups is preferable. Examples of the polyfunctional oligomer include polyester (meth) acrylate, urethane (meth) acrylate, polyester-urethane (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, and isocyanurate. Examples thereof include (meth) acrylate and epoxy (meth) acrylate.

The ionizing radiation polymerizable prepolymer has a weight average molecular weight of more than 10,000, and the weight average molecular weight is preferably 10,000 or more and 80,000 or less, and more preferably 10,000 or more and 40,000 or less. When the weight average molecular weight exceeds 80,000, the viscosity is high, so that the coating suitability is lowered, and the appearance of the obtained light-transmitting resin may be deteriorated. Examples of the polyfunctional prepolymer include urethane (meth) acrylate, isocyanurate (meth) acrylate, polyester-urethane (meth) acrylate, and epoxy (meth) acrylate.

The thermopolymerizable compound has at least one thermopolymerizable functional group in one molecule. The "thermopolymerizable functional group" in the present specification is a functional group capable of polymerizing with each other or with other functional groups by heating. Examples of the thermopolymerizable functional group include a hydroxyl group, a carboxyl group, an isocyanate group, an amino group, a cyclic ether group, and a mercapto group.

The thermopolymerizable compound is not particularly limited, and examples thereof include epoxy compounds, polyol compounds, isocyanate compounds, melamine compounds, urea compounds, and phenol compounds.

The solvent-drying type resin is a resin such as a thermoplastic resin that forms a film simply by drying a solvent added to adjust the solid content at the time of coating. When the solvent-drying resin is added, it is possible to effectively prevent film defects on the coated surface of the coating liquid when the light-transmitting functional layer 15 is formed. The solvent-drying resin is not particularly limited, and in general, a thermoplastic resin can be used.

Examples of the thermoplastic resin include styrene resin, (meth) acrylic resin, vinyl acetate resin, vinyl ether resin, halogen-containing resin, alicyclic olefin resin, polycarbonate resin, polyester resin, and polyamide resin. , Cellulose derivatives, silicone resins and rubbers or elastomers.

The thermoplastic resin is preferably non-crystalline and soluble in an organic solvent (particularly a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, from the viewpoint of transparency and weather resistance, styrene resins, (meth) acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.) and the like are preferable.

<Inorganic particles>
The inorganic particles are components for improving the mechanical orientation strength and the pencil orientation strength of the light-transmitting functional layer 15, and examples of the inorganic particles include silica (SiO ₂ ) particles, alumina particles, titania particles, and zinc oxide. Examples thereof include inorganic oxide particles such as particles, antimony-doped tin oxide (abbreviation: ATO) particles, and zinc oxide particles. Among these, silica particles are preferable from the viewpoint of further increasing the hardness. Examples of the silica particles include spherical silica particles and deformed silica particles, and among these, the deformed silica particles are preferable. In the present specification, the "spherical particles" mean, for example, true spherical particles, elliptical spherical particles, and the like, and the "odd particles" mean particles having a shape having random irregularities on the surface of potatoes. .. Since the surface area of the deformed particles is larger than that of the spherical particles, the contact area with the polymerizable compound and the like is increased by containing such the deformed particles, and the pencil hardness of the light transmissive functional layer 15 is increased. Can be made better. Whether or not the silica particles contained in the light transmissive functional layer 15 are deformed silica particles can be determined by using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM) for the cross section of the light transmissive functional layer 15. It can be confirmed by observing. When spherical silica particles are used, the smaller the particle size of the spherical silica particles, the higher the hardness of the light-transmitting functional layer. On the other hand, the deformed silica particles can achieve the same hardness as the spherical silica even if they are not as small as the spherical silica particles having the smallest particle diameter on the market.

The average particle size of the deformed silica particles is preferably 1 nm or more and 100 nm or less. Even if the average particle size of the irregularly shaped silica particles is in this range, the same hardness as that of spherical silica having an average particle size of 1 nm or more and 45 nm or less can be achieved. The average particle size of the irregularly shaped silica particles is the maximum distance between two points on the outer circumference of the particles from the cross-sectional image of the light transmissive functional layer taken using a transmissive electron microscope (TEM) or a scanning transmissive electron microscope (STEM). Measure the value (major axis) and the minimum value (minor axis), determine the particle size, and exclude the maximum and minimum values from the particle size of 20 particles, and the arithmetic average value of the remaining 18 particle sizes. And. The average particle size of the spherical silica particles is 20 from the cross-sectional image of the particles taken at a magnification of 10,000 to 100,000 times using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM). The particle size of the particles is measured and used as the arithmetic average value of the particle size of 20 particles. A detector (selection signal) when taking a cross-sectional photograph using a scanning transmission electron microscope (STEM) (for example, product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation). Is set to "TE", the acceleration voltage is set to "30 kV", and the emission is set to "10 μA" for observation. For other conditions for taking a cross-sectional photograph by STEM, the conditions described later can be referred to. The average particle size can be calculated by binarizing the image data as described later.

The content of the inorganic particles in the light transmissive functional layer 15 is preferably 20% by mass or more and 70% by mass or less. If the content of the inorganic particles is less than 20% by mass, sufficient hardness can be obtained, and if the content of the inorganic particles is 70% by mass or less, the filling rate does not increase too much, and the inorganic particles and the resin component Since the adhesion to the light-transmitting functional layer is good, the hardness of the light-transmitting functional layer is not lowered.

As the inorganic particles, it is preferable to use inorganic particles having a photopolymerizable functional group on the surface (reactive inorganic particles). Such inorganic particles having a photopolymerizable functional group on the surface can be produced by surface-treating the inorganic particles with a silane coupling agent or the like. As a method of treating the surface of the inorganic particles with a silane coupling agent, a dry method of spraying the silane coupling agent on the inorganic particles or a wet method of dispersing the inorganic particles in a solvent and then adding the silane coupling agent to react. And so on.

<Organic particles>
Organic particles are also components for improving the mechanical orientation strength and pencil orientation strength of the light-transmitting functional layer 15, and examples of the organic particles include plastic beads. Specific examples of the plastic beads include polystyrene beads, melamine resin beads, acrylic beads, acrylic-styrene beads, silicone beads, benzoguanamine beads, benzoguanamine / formaldehyde condensed beads, polycarbonate beads, polyethylene beads and the like.

The light-transmitting functional layer 15 can be formed by using a composition for a light-transmitting functional layer containing a polymerizable compound or the like. The composition for the light-transmitting functional layer contains the above-mentioned polymerizable compound and the like, but in addition, a solvent and a polymerization initiator may be added if necessary. Further, the composition for the light-transmitting functional layer includes conventionally known dispersants, surfactants, and silanes, depending on the purpose of increasing the hardness of the resin layer, suppressing curing shrinkage, controlling the refractive index, and the like. Coupling agents, thickeners, color inhibitors, colorants (pigments, dyes), defoamers, flame retardants, UV absorbers, adhesion enhancers, polymerization inhibitors, antioxidants, surface modifiers, slippery agents Etc. may be added.

<Solvent>
Examples of the solvent include alcohols (methanol, ethanol, propanol, isopropanol, n-butanol, s-butanol, t-butanol, benzyl alcohol, PGME, ethylene glycol, etc.), ketones (acetone, methyl ethyl ketone (MEK), cyclohexanone). , Methyl isobutyl ketone, diacetone alcohol, cycloheptanone, diethyl ketone, etc.), ethers (1,4-dioxane, dioxolane, diisopropyl ether dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic Hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), carbon halides (di dichloromethane, dichloroethane, etc.), esters (methyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, lactic acid) Ethyl, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethyl sulfoxide, etc.), amides (dimethylformamide, dimethylacetamide, etc.), or mixtures thereof.

<Polymerization initiator>
A polymerization initiator is a component that is decomposed by light or heat to generate radicals or ionic species to initiate or proceed with the polymerization (crosslinking) of a polymerizable compound. The polymerization initiator used in the composition for the resin layer is a photopolymerization initiator (for example, a photoradical polymerization initiator, a photocationic polymerization initiator, a photoanionic polymerization initiator) or a thermal polymerization initiator (for example, a thermal radical polymerization initiator). Agents, thermal cationic polymerization initiators, thermal anion polymerization initiators), or mixtures thereof.

When the conductive film 10 is used in a flexible application as described above, it is important that the light transmissive functional layer 15 is brought into close contact with the light transmissive base material 11 and follows the light transmissive base material 11 when folded. It becomes. In order to form a light-transmitting functional layer 15 that adheres to such a light-transmitting base material 11 and can follow the light-transmitting base material 11 when folded, an oxime ester-based compound is used as a polymerization initiator. Is preferable. Examples of commercially available oxime ester compounds include IRGACURE (registered trademark) OXE01, IRGACURE (registered trademark) OXE02, and IRGACURE (registered trademark) OXE03 (all manufactured by BASF Japan Ltd.).

The content of the polymerization initiator in the composition for the light-transmitting functional layer is preferably 0.5 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polymerizable compound. By keeping the content of the polymerization initiator within this range, the hard coating performance can be sufficiently maintained and the curing inhibition can be suppressed.

<< Wall >>
The wall portion 12 has a function of guiding the filling of the conductive portion 13 and a function of suppressing an electrical short circuit between the conductive portion 13 and the dummy conductive portion 14. The wall portion 12 is made of an electrically insulating material. Examples of the electrically insulating material include resin. The resin is not particularly limited, and examples thereof include the light-transmitting resin described in the section of the light-transmitting functional layer.

The width W of the wall portion 12 (see FIG. 4) is preferably 5 μm or more and 500 μm or less. When the width W of the wall portion 12 is 5 μm or more, it is less likely to fall when filled with the conductive fiber dispersion liquid described later, and an electrical short circuit can be further suppressed. When the width W of the wall portion 12 is 500 μm or less, a fine pattern can be arranged. The lower limit of the width W of the wall portion 12 is preferably 10 μm or more, 20 μm or more, or 30 μm or more, and the upper limit is preferably 300 μm or less, 200 μm or less, or 100 μm or less.

The width W of the wall portion 12 was measured by randomly measuring the width of 10 points from a cross-sectional photograph of the wall portion 12 taken with a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM). The arithmetic average value of the width of 8 points excluding the maximum value and the minimum value among the widths of 10 points. The method of taking a cross-sectional photograph of the wall portion 12 is the same as the method of taking a cross-sectional photograph of the conductive portion 13 described later.

The thickness D1 of the wall portion 12 (see FIG. 4) is preferably larger than the thickness D2 of the conductive portion 13 (see FIG. 4). By making the thickness D1 of the wall portion 12 larger than the thickness D2 of the conductive portion 13, an electrical short circuit can be further suppressed. Specifically, it is more preferable that the thickness D1 of the wall portion 12 is 0.02 μm or more larger than the thickness D2 of the conductive portion 13. The thickness D1 of the wall portion 12 is the length of the wall portion 12 in the normal direction of the light transmissive base material 11, and the thickness D2 of the conductive portion 13 is the wall portion 12 in the normal direction of the light transmissive base material 11. Is the length of.

The thickness D1 of the wall portion 12 (see FIG. 4) is preferably 0.1 μm or more and 100 μm or less. When the thickness D1 of the wall portion 12 is 0.1 μm or more, it is possible to prevent the conductive fiber dispersion liquid from overflowing when the conductive fiber dispersion liquid described later is filled. When the thickness D1 of the wall portion 12 is 50 μm or less, the foldability can be guaranteed and the followability at the time of bonding can be guaranteed. The lower limit of the thickness D1 of the wall portion 12 is preferably 0.2 μm or more, 0.5 μm or more, or 1 μm or more, and the upper limit is preferably 40 μm or less, 30 μm or less, or 25 μm or less.

The thickness D1 of the wall portion 12 was measured by randomly measuring the thickness at 10 points from a cross-sectional photograph of the wall portion 12 taken with a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM). Of the 10 thicknesses, the arithmetic average value of the 8 thicknesses excluding the maximum and minimum values. The method of taking a cross-sectional photograph of the wall portion 12 is the same as the method of taking a cross-sectional photograph of the conductive portion 13 described later.

The absolute value of the refractive index difference between the wall portion 12 and the light-transmitting base material 11 (| the refractive index of the wall portion 12-the refractive index of the light-transmitting base material 11 |) is preferably 0.2 or less. When the difference in refractive index is 0.2 or less, an increase in the haze value can be suppressed, and the shape of the wall portion 12 can be suppressed from being visually recognized (bone visibility phenomenon).

The refractive index of the wall portion 12 and the like can be measured by, for example, the Becke method. When the refractive index of the wall portion 12 is measured by the Becke method, 10 pieces of the wall portion 12 are cut out, and the refractive index of the 10 pieces cut out is determined by the Becke method using a refractive index standard solution. The index of refraction of the wall portion 12 is defined as the average value of 10 pieces of the refractive index of the measured pieces. The refractive index of the light transmissive substrate 11 or the like can also be measured by the same method as the refractive index of the optical adjustment layer.

<< Conductive part >>
The conductive portion 13 is filled between the wall portions 12. The "conductive portion" in the present specification means that when a cross section is observed using a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM), conductive fibers are confirmed and conductive from the surface. Means the part. When it is difficult to confirm the interface of the conductive portion, it is advisable to perform a pretreatment generally used in electron microscope observation such as forming a metal layer such as Pt-Pd or Au by a sputtering method on the surface of the conductive portion. Further, if a dyeing treatment such as osmium tetroxide, ruthenium tetroxide, or phosphotungstic acid is performed, the interface between the organic layers becomes easy to see. Therefore, the entire conductive film may be embedded with a resin and then dyed.

As shown in FIG. 3, the conductive portion 13 includes a plurality of conductive fibers 16. The "conductive fibers" in the present specification are those having conductivity and having a shape whose length is sufficiently longer than the thickness (for example, diameter), for example, the length is generally thick. Those five times or more shall be contained in conductive fibers.

The conductive portion 13 is electrically conductive from the surface of the surface 13A of the conductive portion 13. Whether or not the conductive portion 13 is electrically conductive from the surface 13A can be determined by obtaining the surface resistance value of the conductive portion 13 or by measuring the linear resistance value.

When determining conduction from the surface resistance value of the conductive portion 13, if the surface resistance value of the conductive portion 13 is less than 2000Ω / □, it can be determined that electrical conduction is obtained from the surface of the conductive portion 13. .. The surface resistance value of the conductive portion 13 shall be obtained as follows. First, a sample is cut out from the conductive film 10 to a size of 5 mm × 100 mm so that the direction in which the conductive portion 13 extends is the longitudinal direction. Then, a linear silver paste extending in the width direction of the conductive portions is applied to both ends of the conductive portions 13 of this sample so as to straddle the plurality of conductive portions 13. The silver paste is then cured by heating at 130 ° C. for 30 minutes. After that, the cured silver paste is irradiated with laser light to remove a part of the silver paste 21 so that the dummy conductive portion 14 does not electrically conduct with the conductive portion 13. In that state, by contacting the probe terminals of a tester (product name "Digital MΩ Hister 3454-11", manufactured by Hioki Electric Co., Ltd.) in an environment with a temperature of 23 ± 5 ° C. and a relative humidity of 30% or more and 70% or less. Measure the resistance value. Specifically, since the Digital MΩ Hister 3454-11 has two probe terminals (red probe terminal and black probe terminal, both pin-shaped), the red probe terminal is conductive in one of the cured silver pastes. The resistance value is measured by bringing the black probe terminal into contact with the portion in contact with the portion 13 and contacting the black probe terminal with the portion in contact with the conductive portion 13 in the other cured silver paste. Then, the surface resistance value of the conductive portion is obtained from the following mathematical formula (2).
Rs = R × (C _W × C _N / C _L )… (2)
In the above equation (2), Rs is the surface resistance value (Ω / □), R is the measured resistance value (Ω), C _W is the line width (μm) of one conductive portion, and C _N is the number of the conductive portion, the C _L is the line length of the conductive portion ([mu] m).

The surface resistance value of the conductive portion 13 is preferably 3Ω / □ or more and 1000Ω / □ or less. If the surface resistance value of the conductive portion 13 is 3 Ω / □ or more, the optical performance is sufficient, and if the surface resistance value of the conductive portion 13 is 1000 Ω / □ or less, the response speed is slow, especially in touch panel applications. It is possible to suppress problems such as becoming. The lower limit of the surface resistance value of the conductive portion 13 is more preferably 5Ω / □ or more, or 10Ω / □ or more, and the upper limit of the surface resistance value of the conductive portion 13 is 100Ω / □ or less, 70Ω / □ or less, It is more preferably 60Ω / □ or less, or 50Ω / □ or less.

When determining the continuity from the linear resistance value of the conductive portion 13, it can be determined that electrical conduction is obtained from the surface of the conductive portion 13 if at least the linear resistance value of the conductive portion 13 is less than 20000Ω. The linear resistance value of the conductive portion 13 shall be obtained as follows. First, the resistance value of the sample is measured in the same manner as the surface resistance value of the conductive portion 13. Then, the linear resistance value of the conductive portion 13 is obtained from the following mathematical formula (3).
_RL = R × C _N … (3)
In the above equation (3), _RL is the linear resistance value (Ω), R is the measured resistance value (Ω), and _CN is the number of conductive parts.

The linear resistance value of the conductive portion 13 is preferably 15000Ω or less. When the line resistance values of the conductive portions 13 are 15000 Ω or less, problems such as slow response speed can be suppressed, especially in touch panel applications. The lower limit of the linear resistance value of the conductive portion 13 is more preferably 20 Ω or more, 100 Ω or more, or 200 Ω or more, respectively, and the upper limit of the linear resistance value of the conductive portion 13 is 12000 Ω or less, 1000 Ω or less, or 8000 Ω or less, respectively. Is preferable.

As the thickness of the conductive portion increases, the portion where the conductive fibers overlap each other increases, so that a low line resistance value can be achieved. However, if the conductive fibers overlap too much, the cost increases and the haze value becomes low. It can be difficult to maintain. Therefore, the thickness of the conductive portion 13 is preferably 300 nm or less. As long as the low line resistance value can be maintained, the thickness of the conductive portion is preferably as thin as possible from the viewpoint of optical characteristics and thinning. The upper limit of the thickness of the conductive portion 13 is 200 nm or less, 145 nm, 140 nm or less, 120 nm or less, 110 nm or less, 80 nm or less, or 50 nm or less, respectively, from the viewpoint of reducing the thickness and obtaining good optical characteristics such as low haze value. More preferably. Further, the lower limit of the thickness of the conductive portion 13 is preferably 10 nm or more. When the thickness of the conductive portion 13 is 10 nm or more, stable electrical conduction can be obtained. In order to obtain more stable electrical conduction, it is desirable that two or more conductive fibers are overlapped and contacted. Therefore, the lower limit of the film thickness of the conductive portion 13 is more preferably 20 nm or more or 30 nm or more. preferable. In order to obtain flexibility, if the interval φ is large and the number of times of folding is about 100,000, a stable linear resistance value can be obtained if the film thickness of the conductive portion 13 is 300 nm or less. Further, when the interval φ becomes small and the number of times of folding exceeds 100,000 times, the thickness of the conductive portion 13 is preferably thin, for example, 200 nm or less, 145 nm or less, and further preferably 120 nm or less.

The thickness D2 of the conductive portion 13 was measured by randomly measuring the thickness at 10 points from a cross-sectional photograph of the conductive portion 13 taken with a scanning transmission electron microscope (STEM) or a transmission electron microscope (TEM). Of the 10 thicknesses, the arithmetic average value of the 8 thicknesses excluding the maximum and minimum values.

A specific method for taking a cross-sectional photograph is described below. First, a sample for cross-section observation is prepared from the conductive film by the same method as described above. If continuity is not obtained in this sample, it may be difficult to see the observation image by STEM, so it is preferable to sputter Pt-Pd for about 20 seconds. The sputtering time can be adjusted as appropriate, but care must be taken because 10 seconds is short and 100 seconds is too long, so that the sputtered metal becomes a particulate foreign matter image. Then, a cross-sectional photograph of a sample for STEM is taken using a scanning transmission electron microscope (STEM) (for example, product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation). When taking this cross-sectional photograph, STEM observation is performed with the detector (selection signal) set to "TE", the acceleration voltage set to "30 kV", and the emission set to "10 μA". Regarding the magnification, adjust the focus and adjust the contrast and brightness appropriately at 5000 to 200,000 times while observing whether each layer can be distinguished. The preferred magnification is 10,000 to 100,000 times, the more preferable magnification is 10,000 to 50,000 times, and the most preferable magnification is 25,000 to 50,000 times. When taking a cross-sectional photograph, the beam monitor aperture was set to 3, the objective lens aperture was set to 3, and W. D. May be 8 mm. When measuring the film thickness of the first conductive portion and the second conductive portion, the interfacial contrast between the conductive portion and another layer (light-transmitting base material, embedded resin, etc.) is possible when the cross section is observed. It is important to be able to observe as clearly as possible. If this interface is difficult to see due to insufficient contrast, pretreatment generally used in electron microscope observation such as forming a metal layer such as Pt-Pd, Pt or Au by a sputtering method on the surface of the conductive portion is performed. You may go. Further, if a dyeing treatment such as osmium tetroxide, ruthenium tetroxide, or phosphotungstic acid is performed, the interface between the organic layers becomes easy to see, so the dyeing treatment may be performed. In addition, the contrast at the interface may be difficult to understand when the magnification is high. In that case, observe the low magnification at the same time. For example, observe at two magnifications, high and low, such as 25,000 times and 50,000 times, and 50,000 times and 100,000 times, obtain the above-mentioned arithmetic mean value at both magnifications, and further calculate the average value of the conductive part. The value of the line thickness.

The conductive portion 13 functions as, for example, an electrode in the X direction in a projection type capacitance type touch panel, and as shown in FIG. 2, a plurality of sensor portions 13B extending in the X direction and each sensor portion 13B. It is equipped with a terminal unit (not shown) connected to. Each sensor unit 13B is provided in a rectangular active area which is an area where the touch position can be detected, and the terminal unit is a non-area which is adjacent to the active area and surrounds the active area in a circumferential shape from all sides. It is provided in the active area.

Each sensor portion 13B has a line portion 13C extending linearly and a bulging portion 13D bulging from the line portion 13C. In FIG. 2, the line portion 13C extends linearly along a direction intersecting the arrangement direction of the sensor portion 13B. The bulging portion 13D is a portion bulging from the line portion 13C. Therefore, the width of each sensor portion 13B is increased at the portion where the bulging portion 13D is provided. In the present embodiment, the bulging portion 13D has an outer contour having a substantially square shape in a plan view. The bulging portion 13D is not limited to a substantially square shape in a plan view, and may be a diamond shape or a striped shape.

<Conductive fiber>
A plurality of conductive fibers 16 are present in the conductive portion 13. Since it is electrically conductive from the surface 13A of the conductive portion 13, the conductive fibers 16 are in contact with each other in the thickness direction of the conductive portion 13.

In the conductive portion 13, it is preferable that the conductive fibers 16 come into contact with each other to form a network structure (mesh structure) in the plane direction (two-dimensional direction) of the conductive portion 13. By forming the network structure of the conductive fibers 16, the conductive path can be formed.

The average fiber diameter of the conductive fibers 16 is preferably 30 nm or less. When the average fiber diameter of the conductive fibers 16 is 30 nm or less, an increase in the haze value of the conductive film 10 can be suppressed, and the light transmission performance becomes sufficient. The lower limit of the average fiber diameter of the conductive fibers 16 is more preferably 5 nm or more, 7 nm or more, and 10 nm or more from the viewpoint of the conductivity of the conductive portion 13. Further, the upper limit of the average fiber diameter of the conductive fibers 16 is more preferably 28 nm or less, 25 nm or less, or 20 nm or less. In order to control the balance between the resistance value and the haze value in a preferable range, the more preferable range of the fiber diameter of the conductive fiber 16 is 7 nm or more and 25 nm or less.

The average fiber diameter of the conductive fibers 16 is 100,000 to 200,000 times, for example, using a transmission electron microscope (TEM) (for example, product name "H-7650", manufactured by Hitachi High-Technologies Corporation). It is assumed that 50 images are imaged, the fiber diameters of 100 conductive fibers are actually measured on the imaging screen by the software attached to the TEM, and the arithmetic average value is obtained. When measuring the fiber diameter using the above H-7650, the acceleration voltage is "100 kV", the emission current is "10 μA", the focusing lens diaphragm is "1", the objective lens diaphragm is "0", and the observation mode is set. Set "HC" and Spot to "2". It is also possible to measure the fiber diameter of conductive fibers with a scanning transmission electron microscope (STEM) (for example, product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation). When STEM is used, 50 images are taken at 100,000 to 200,000 times, the fiber diameter of 100 conductive fibers is actually measured on the imaging screen using the software attached to STEM, and the arithmetic mean value is conductive. The average fiber diameter of sex fibers shall be determined. When measuring the fiber diameter using the above S-4800 (TYPE2), the signal selection is "TE", the acceleration voltage is "30 kV", the emission current is "10 μA", the probe current is "Norm", and the focus mode. Is "UHR", condenser lens 1 is "5.0", W. D. Is set to "8 mm" and Til is set to "0 °".

When measuring the fiber diameter of the conductive fiber 16, a measurement sample prepared by the following method is used. Here, since the TEM measurement has a high magnification, it is important to reduce the concentration of the conductive fiber dispersion liquid as much as possible so that the conductive fibers do not overlap as much as possible. Specifically, the conductive fiber dispersion liquid is diluted with water or alcohol to a concentration of 0.05% by mass or less, or a solid content of 0.2% by mass or less, according to the dispersion medium. Is preferable. Further, one drop of this diluted conductive fiber dispersion is dropped on a grid mesh with a carbon support film for TEM or STEM observation, dried at room temperature, and observed under the above conditions to obtain observation image data. Based on this, the arithmetic mean value is calculated. As the grid mesh with a carbon support film, the Cu grid model number "# 10-1012 Elastic Carbon ELS-C10 STEM Cu100P Grid Specification" is preferable, and it is high because it is strong against electron beam irradiation and has better electron beam transmittance than the plastic support film. Those suitable for magnification and resistant to organic solvents are preferable. Further, when dropping, it is preferable to place the grid mesh on the slide glass and drop it because the grid mesh alone is too small to drop.

The fiber diameter can be obtained by actually measuring it based on a photograph, or may be calculated by binarizing processing based on image data. In the case of actual measurement, a photograph may be printed and enlarged as appropriate. At that time, the conductive fibers are reflected in a darker density than the other components. The measurement point is measured with the outside of the contour as the starting point and the ending point. The concentration of conductive fibers shall be determined by the ratio of the mass of conductive fibers to the total mass of the conductive fiber dispersion liquid, and the solid content shall be a component other than the dispersion medium (conductiveness) with respect to the total mass of the conductive fiber dispersion liquid. It shall be determined by the mass ratio of fibers, resin components, and other additives). The fiber diameter obtained by using the conductive fiber-containing composition and the fiber diameter obtained by actual measurement based on the photograph are almost the same value.

The average fiber length of the conductive fibers 16 is preferably 15 μm or more and 20 μm or less in order to suppress the feeling of cloudiness. If the average fiber length of the conductive fibers 16 is 15 μm or more, a conductive layer having sufficient conductive performance can be formed, and there is no risk of the influence of cloudiness due to aggregation, an increase in haze value, or a decrease in light transmission performance. .. Further, if the average fiber length of the conductive fibers 16 is 20 μm or less, coating can be performed without clogging the filter. The lower limit of the average fiber length of the conductive fiber 16 may be 5 μm or more, 7 μm or more and 10 μm or more, and the upper limit of the average fiber length of the conductive fiber 16 may be 40 μm or less, 35 μm or less, or 30 μm or less.

The average fiber length of the conductive fibers 16 is 500 to 2000, for example, using the SEM function of a scanning electron microscope (SEM) (for example, product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation). 10 images were taken at 10,000 times, and the fiber length of 100 conductive fibers was measured on the imaging screen using the attached software, and 98 of the 100 conductive fibers excluding the maximum and minimum values. It shall be calculated as the arithmetic mean value of the fiber length of. When measuring the fiber length using the above S-4800 (TYPE2), a 45 ° inclined sample table is used, the signal selection is "SE", the acceleration voltage is "3 kV", and the emission current is "10 μA". ~ 20 μA ”, SE detector“ mixed ”, probe current“ Norm ”, focus mode“ UHR ”, condenser lens 1“ 5.0 ”, W. D. Is set to "8 mm" and Til is set to "30 °". Since the TE detector is not used during SEM observation, be sure to remove the TE detector before SEM observation. The S-4800 can select the STEM function and the SEM function, but the SEM function is used when measuring the fiber length.

When measuring the fiber length of the conductive fiber 16, a measurement sample prepared by the following method is used. First, the conductive fiber dispersion was applied to the untreated surface of a B5 size polyethylene terephthalate (PET) film having a thickness of 50 μm so that the amount of the conductive fiber applied was 10 mg / m ^2, and the dispersion medium was dried. Conductive fibers are arranged on the surface of the PET film to prepare a conductive film. It is cut out from the central part of this conductive film to a size of 10 mm × 10 mm. Then, the cut-out conductive film is put on a silver paste on an SEM sample table having a 45 ° inclination (model number "728-45", manufactured by Nissin EM, inclined sample table 45 °, φ15 mm × 10 mm, made of M4 aluminum). Attach it flat to the surface of the table using. Further, Pt-Pd is sputtered for 20 to 30 seconds to obtain continuity. The image may be difficult to see without an appropriate sputter film. In that case, adjust appropriately.

The fiber length can be actually measured and obtained based on a photograph, or may be calculated by binarizing processing based on image data. When actually measuring based on a photograph, the same method as above shall be used. The fiber length obtained by using the conductive fiber-containing composition and the fiber length actually measured based on the photograph are almost the same value.

The conductive fiber 16 is preferably at least one fiber selected from the group consisting of conductive carbon fibers, metal fibers such as metal nanowires, metal-coated organic fibers, metal-coated inorganic fibers, and carbon nanotubes.

Examples of the conductive carbon fiber include a vapor phase growth method carbon fiber (VGCF), carbon nanotube, wire cup, wire wall and the like. One type or two or more types of these conductive carbon fibers can be used.

Examples of the metal fiber include stainless steel, Ag, Cu, Au, Al, Rh, Ir, Co, Zn, Ni, In, Fe, Pd, Pt, Sn, Ti, or a metal composed of an alloy thereof. Nanowires are preferable, and among metal nanowires, silver nanowires are preferable from the viewpoints of being able to realize a low resistance value, being difficult to oxidize, and being suitable for wet coating. As the metal fiber, for example, a fiber produced by a wire drawing method or a cutting method in which the metal is stretched thinly and longly can be used. One kind or two or more kinds of such metal fibers can be used.

When silver nanowires are used as the metal fibers, the silver nanowires can be synthesized by liquid phase reduction of a silver salt (eg, silver nitrate) in the presence of a polyol (eg, ethylene glycol) and poly (vinylpyrrolidone). Mass production of uniform size silver nanowires is described, for example, in Xia, Y. et al. et al. , Chem. Mater. (2002), 14, 4736-4745 and Xia, Y. et al. et al. , Nanoletters (2003) 3 (7), 955-960.

The means for producing the metal nanowires is not particularly limited, and for example, known means such as a liquid phase method and a gas phase method can be used. Further, the specific production method is not particularly limited, and a known production method can be used. For example, as a method for producing silver nanowires, Adv. Mater. , 2002, 14, 833-837; Chem. Mater. , 2002, 14, 4736-4745, etc., as a method for producing gold nanowires, JP-A-2006-233252, etc., as a method for producing Cu nanowires, JP-A-2002-266007, etc., as a method for producing cobalt nanowires. Japanese Patent Publication No. 2004-149871 and the like can be referred to.

Examples of the metal-coated synthetic fiber include fibers obtained by coating acrylic fiber with gold, silver, aluminum, nickel, titanium, or the like. One kind or two or more kinds of such metal-coated synthetic fibers can be used.

<< Dummy conductive part >>
The dummy conductive portion 14 has a function of suppressing the shape of the conductive portion 13 from being visually recognized. It is filled between the wall portions 12 different from the conductive portion 13. The dummy conductive portion 14 and the conductive portion 13 are electrically insulated from each other. Further, the dummy conductive portions 14 are alternately arranged with the conductive portions 13 via the wall portions 12.

The dummy conductive portion 14 includes a plurality of conductive fibers 16. By including the conductive fibers 16 in the dummy conductive portion 14, it is possible to prevent the shape of the conductive portion 13 from being visually recognized. Since the conductive fibers 16 in the dummy conductive portion 14 are the same as the conductive fibers 16 in the conductive portion 13, the description thereof will be omitted here. Since the dummy conductive portion 14 has the structure and physical property values of the conductive portion 13, the description thereof will be omitted here.

<< Manufacturing method of conductive film >>
The conductive film 10 can be produced, for example, as follows. First, as shown in FIG. 9A, the composition for the light-transmitting functional layer is applied to the second surface 11B of the light-transmitting base material 11, dried, and the composition for the light-transmitting functional layer is dried. The coating film 31 is formed.

Examples of the method for applying the composition for the light transmissive functional layer include known coating methods such as spin coating, dip method, spray method, slide coating method, bar coating method, roll coating method, gravure coating method, and die coating method. Be done.

Next, as shown in FIG. 9B, the coating film 31 is irradiated with ionizing radiation such as ultraviolet rays or heated to polymerize (crosslink) the polymerizable compound to cure the coating film 31, resulting in light. The permeable functional layer 15 is formed.

When ultraviolet rays are used as the light for curing the composition for the light transmissive functional layer, ultraviolet rays emitted from ultra-high pressure mercury lamps, high pressure mercury lamps, low pressure mercury lamps, carbon arcs, xenon arcs, metal halide lamps, etc. can be used. .. Further, as the wavelength of ultraviolet rays, a wavelength range of 190 to 380 nm can be used. Specific examples of the electron beam source include various electron beam accelerators such as Cockcroft-Walt type, bandegraft type, resonant transformer type, insulated core transformer type, linear type, dynamistron type, and high frequency type.

After forming the light-transmitting functional layer 15 on the light-transmitting base material 11, a plurality of wall portions 12 are formed on the first surface 11A of the light-transmitting base material 11 as shown in FIG. 10 (A). To do. For example, the wall portion 12 can be formed by applying a composition for a wall portion containing a polymerizable compound such as an ionizing radiation polymerizable compound and curing it. The application of the wall composition is performed by, for example, flexographic printing, offset printing, gravure printing, screen printing, an inkjet method, or a dispenser.

After forming the plurality of wall portions 12, a conductive fiber dispersion liquid containing the conductive fibers 16 and the dispersion medium is applied between the wall portions 12 to form the coating film 32 as shown in FIG. 10 (B). .. The application of the conductive fiber dispersion liquid is not particularly limited, but may be performed by an inkjet method or a dispenser.

The conductive fiber dispersion liquid may contain a resin component composed of a thermoplastic resin or a polymerizable compound in addition to the conductive fibers 16 and the dispersion medium. The term "resin" as used herein refers to resin (however, to prevent self-welding of conductive fibers covering the conductive fibers and reaction with substances in the atmosphere, etc., during the synthesis of conductive fibers. In addition to the resin (for example, polyvinylpyrrolidone, etc.) that constitutes the organic protective layer formed around the fibers, the concept includes components that can be polymerized to become a resin, such as a polymerizable compound.

The dispersion medium may be either an aqueous dispersion medium or an organic dispersion medium. However, if the content of the resin content in the conductive fiber dispersion is too large, the resin content may enter between the conductive fibers, and the continuity of the conductive portion may deteriorate. In particular, when the film thickness of the conductive portion is thin, the continuity of the conductive portion tends to deteriorate. On the other hand, the resin content in the conductive fiber dispersion is smaller when the organic dispersion medium is used than when the aqueous dispersion medium is used. Therefore, when forming the conductive portion 13 having a thin film thickness, for example, a film thickness of 300 nm, it is preferable to use an organic dispersion medium. The organic dispersion medium may contain less than 10% by mass of water.

The organic dispersion medium is not particularly limited, but is preferably a hydrophilic organic dispersion medium. Examples of the organic dispersion medium include saturated hydrocarbons such as hexane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, propanol and butanol; acetone, methyl ethyl ketone (MEK) and methyl isobutyl ketone. , Ketones such as diisobutylketone; esters such as ethyl acetate and butyl acetate; ethers such as tetrahydrofuran, dioxane and diethyl ether; N, N-dimethylformamide, N-methylpyrrolidone (NMP), N, N-dimethylacetamide And the like; examples thereof include halogenated hydrocarbons such as ethylene chloride and chlorbenzene. Among these, alcohols are preferable from the viewpoint of stability of the conductive fiber dispersion liquid.

Examples of the thermoplastic resin that may be contained in the conductive fiber dispersion liquid include acrylic resins; polyester resins such as polyethylene terephthalate; aromatic resins such as polystyrene, polyvinyltoluene, polyvinylxylene, polyimide, polyamide, and polyamideimide. Polyurethane resin; Epoxy resin; Polyolefin resin; Acrylonitrile-butadiene-styrene copolymer (ABS); Cellulosic resin; Polyvinyl chloride resin; Polyacetate resin; Polynorbornene resin; Synthetic rubber; Fluorine resin Examples include resin.

Examples of the polymerizable compound that may be contained in the conductive fiber dispersion include the same polymerizable compounds as those described in the column of the light-transmitting functional layer 15, and thus the description thereof will be omitted here. ..

After that, as shown in FIG. 10C, the coating film 32 is dried to form the conductive portion 13 and the dummy conductive portion 14, whereby the conductive film 10 is obtained.

According to this embodiment, since the conductive fiber dispersion liquid is filled between the wall portions 12 to form the conductive portion 13, it is not necessary to perform patterning by etching. As a result, unnecessary conductive fibers 16 can be reduced, so that cost can be reduced. Further, since etching is not required, the number of steps can be reduced and the manufacturing time can be shortened.

According to the present embodiment, since the conductive portion 13 is formed between the wall portions 12, the migration of the conductive material from the conductive portion 13 can be suppressed by the wall portion 12, whereby the conductive portion 13 and the dummy conductive portion 14 can be suppressed. It is possible to suppress an electrical short circuit between them.

According to the present embodiment, since the conductive fiber 16 is used, unlike ITO, it is possible to provide the conductive film 10 which is hard to break even if it is bent.

The use of the conductive film according to the present embodiment is not particularly limited, but it can be incorporated into an image display device including a sensor and a touch panel. FIG. 11 is a schematic configuration diagram of the image display device according to the present embodiment, and FIG. 12 is a plan view of a part of the conductive film of the image display device of FIG.

<<< Image display device >>>
The image display device 40 shown in FIG. 11 includes a display element 50, a circular polarizing plate 60, a touch panel 70, and a cover member 80 in this order toward the observer side. The display element 50 and the circular polarizing plate 60, the circular polarizing plate 60 and the touch panel 70, and the touch panel 70 and the cover member 80 are adhered to each other via adhesive layers 91 to 93. "Adhesion" as used herein is a concept including adhesion.

<< Display element >>
Examples of the display element 50 include a liquid crystal element, an organic light emitting diode element (hereinafter, also referred to as an “OLED element”), an inorganic light emitting diode element, a micro LED, a plasma element, and the like. As the organic light emitting diode element, a known organic light emitting diode element can be used. Further, the liquid crystal display element may be an in-cell touch panel liquid crystal display element having a touch panel function inside the element.

<< Circularly polarized light >>
Since the circularly polarizing plate 60 has a function of suppressing reflection of external light, the circularly polarizing plate 60 is particularly effective when an OLED element is used as a display element. The circular polarizing plate 60 is provided with, for example, a first retardation film, an adhesive layer, a second retardation film, an adhesive layer, and a polarizing plate in this order toward the observer side.

The thickness of the circular polarizing plate 60 is preferably 100 μm or less from the viewpoint of reducing the thickness. The lower limit of the thickness of the circular polarizing plate 60 is preferably 20 μm or more, 30 μm or more, or 50 μm or more from the viewpoint of workability due to a decrease in strength. Further, the upper limit of the thickness of the circular polarizing plate 60 is more preferably 95 μm or less, 90 μm or less, and 80 μm or less. The thickness of the circular polarizing plate 60 is determined by photographing the cross section of the circular polarizing plate 60 using a scanning electron microscope (SEM) and measuring the thickness of the circular polarizing plate 60 at 10 points in the image of the cross section. It can be obtained by calculating the arithmetic average value of the membrane.

The circular polarizing plate 60 may be incorporated into the image display device by either a chip cutting method or a roll-to-panel method. The chip cutting method is a method in which a circularly polarizing plate having a predetermined size is cut out from a roll-shaped circularly polarizing plate according to the size of an image display device and attached to a cover member such as glass via an adhesive layer. Further, the roll-to-panel method is a method in which a roll-shaped circularly polarizing plate is cut while being sent out in a manufacturing line of an image display device, and is attached to a cover member such as glass via an adhesive layer.

<< Touch panel >>
The touch panel 70 includes a conductive film 71 and a conductive film 10 arranged on the observer side of the conductive film 71. The conductive film 71 has almost the same structure as the conductive film 10, and includes a light-transmitting base material 72, a wall portion 73, a conductive portion 74, a dummy conductive portion 75, and a light-transmitting functional layer 76. I have. The light-transmitting base material 72 is the same as the light-transmitting base material 11, the wall portion 73 is the same as the wall portion 12, and the dummy conductive portion 75 is the same as the dummy conductive portion 14. Since the light transmissive functional layer 76 is the same as the light transmissive functional layer 15, the description thereof will be omitted here.

<Conductive part>
The conductive portion 74 functions as an electrode in the Y direction in a projection type capacitance type touch panel, and as shown in FIG. 12, a plurality of sensor portions 74B and a terminal portion (terminal portion) connected to each sensor portion 74B ( (Not shown). The sensor portion 74B has a line portion 74C extending in the Y direction and extending linearly, and a bulging portion 74D bulging from the line portion 74C.

<< Cover member >>
The surface 80A of the cover member 80 is the surface 40A of the image display device 40. The cover member 80 may be a cover film made of cover glass or resin. When the image display device 40 has flexibility, it is preferable that the cover member 80 is made of flexible glass or flexible resin. Examples of the flexible resin include a polyimide resin, a polyamideimide resin, a polyamide resin, a polyester resin (for example, a polyethylene terephthalate resin and a polyethylene naphthalate resin), or a mixture of two or more of these resins. Can be mentioned.

<< Adhesive layer >>
The adhesive layers 91 to 93 can be composed of a cured product of a liquid ionizing radiation curable adhesive (for example, OCR: Optically Clear Resin) or an adhesive (for example, OCA: Optical Clear Adhesive) containing a polymerizable compound. Is.

In order to explain the present invention in detail, examples will be given below, but the present invention is not limited to these descriptions.

<Preparation of composition for hard coat layer>
First, each component was blended so as to have the composition shown below to obtain a composition 1 for a hard coat layer.
(Composition for hard coat layer 1)
-Mixed mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (trade name "KAYARAD PET-30", manufactured by Nippon Kayaku Co., Ltd.): 30 parts by mass-polymerization initiator (trade name "Irgacure (registered trademark) 184", BASF Made in Japan): 1.5 parts by mass, methyl ethyl ketone (MEK): 50 parts by mass, cyclohexanone: 18.5 parts by mass

<Preparation of silver nanowire dispersion>
(Silver nanowire dispersion liquid 1)
Ethylene glycol as an alcohol solvent, silver nitrate as a silver compound, sodium chloride as a chloride, sodium bromide as a bromide, sodium hydroxide as an alkali metal hydroxide, aluminum nitrate nineahydrate as an aluminum salt, and vinylpyrrolidone as an organic protective agent. A copolymer of diallyldimethylamnium nitrate (complex prepared with 99% by mass of vinylpyrrolidone and 1% by mass of diallyldimethylammonium nitrate, weight average molecular weight of 130,000) was prepared.

Copolymer of sodium chloride 0.041 g, sodium bromide 0.00072 g, sodium hydroxide 0.0506 g, aluminum nitrate nine hydrate 0.0416 g, vinylpyrrolidone and diallyldimethylammonium nitrate in 540 g of ethylene glycol at room temperature. 5.24 g was added and dissolved to give solution A. In a separate container, 4.25 g of silver nitrate was added to and dissolved in 20 g of ethylene glycol to prepare a solution B. In this example, the Al / OH molar ratio was 0.0876 and the OH / Ag molar ratio was 0.0506.

The total amount of the solution A was heated from room temperature to 115 ° C. with stirring, and then the total amount of the solution B was added to the solution A over 1 minute. After the addition of the solution B was completed, the stirring state was further maintained and maintained at 115 ° C. for 24 hours. Then, the reaction solution was cooled to room temperature. After cooling, acetone was added to the reaction solution in an amount 10 times that of the reaction solution, and the mixture was stirred for 10 minutes and allowed to stand for 24 hours. After standing, a concentrate and a supernatant were observed, so the supernatant was carefully removed with a pipette to obtain a concentrate.

500 g of pure water was added to the obtained concentrate, and the mixture was stirred for 10 minutes to disperse the concentrate, 10 times more acetone was added, and the mixture was allowed to stand for 24 hours after stirring. After standing, a new concentrate and supernatant were observed, so the supernatant was carefully removed with a pipette. Since an excess organic protective agent is unnecessary for obtaining good conductivity, this cleaning operation was performed about 1 to 20 times as necessary to sufficiently clean the solid content.

Pure water was added to the solid content after washing to obtain a dispersion of this solid content. This dispersion was separated, the pure water of the solvent was volatilized on an observation table, and then observed with a high-resolution FE-SEM (high-resolution field emission scanning electron microscope). As a result, the solid content was found to be silver nanowires. confirmed.

Isopropyl alcohol was added to the washed silver nanowires to obtain a silver nanowire dispersion liquid 1. When the average fiber diameter and the average fiber length of the silver nanowires in the silver nanowire dispersion liquid 1 were measured, the average fiber diameter of the silver nanowires was 45 nm, and the average fiber length was 15 μm. The concentration of silver nanowires in the silver nanowire dispersion 1 was 1.5 mg / ml.

The average fiber diameter of silver nanowires is 50 images taken at 100,000 to 200,000 times using a transmission electron microscope (TEM) (product name "H-7650", manufactured by Hitachi High-Technologies Corporation), and TEM. The fiber diameters of 100 conductive fibers were actually measured on the imaging screen using the attached software, and the average value was calculated. When measuring the fiber diameter, the acceleration voltage is "100 kV", the emission current is "10 μA", the focusing lens diaphragm is "1", the objective lens diaphragm is "0", the observation mode is "HC", and the spot is "Spot". 2 ". In addition, the average fiber length of silver nanowires is 100 wires at a magnification of 5 to 20 million times using a scanning electron microscope (SEM) (product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation). The fiber length of the silver nanowires was measured, and among the fiber lengths of the 100 silver nanowires, 98 were calculated as the arithmetic mean value excluding the maximum value and the minimum value. When measuring the fiber length, the signal selection was "SE", the acceleration voltage was "3 kV", the emission current was "10 μA", and the SE detector was "mixed". The fiber length of silver nanowires was determined by using the SEM function of a scanning electron microscope (SEM) (product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation), and 10 images were taken at a magnification of 5 to 20 million. The fiber length of 100 silver nanowires is measured on the imaging screen using the attached software, and the arithmetic mean value of 98 lines excluding the maximum and minimum values is obtained from the fiber lengths of the 100 silver nanowires. It was. When measuring the fiber length, a sample table with a 45 ° inclination is used, the signal selection is "SE", the acceleration voltage is "3 kV", the emission current is "10 μA to 20 μA", and the SE detector is "mixed". , Probe current is "Norm", focus mode is "UHR", condenser lens 1 is "5.0", W. D. Was set to "8 mm" and Til was set to "30 °". The TE detector was removed in advance. When measuring the fiber diameter of silver nanowires, a measurement sample prepared by the following method was used. First, the silver nanowire dispersion liquid 1 was diluted with ethanol to a concentration of 0.05% by mass or less in accordance with the dispersion medium. Further, one drop of this diluted silver nanowire dispersion liquid 1 is dropped onto a grid mesh with a carbon support film for TEM or STEM observation (Cu grid model number "# 10-1012 Elastic Carbon ELS-C10 STEM Cu100P grid specification"). It was dried at room temperature and observed under the above conditions to obtain observation image data. Based on this, the arithmetic mean value was calculated. When measuring the fiber length of silver nanowires, a measurement sample prepared by the following method was used. First, silver nanowire dispersion 1 is applied to the untreated surface of a B5 size polyethylene terephthalate (PET) film having a thickness of 50 μm so that the amount of silver nanowires applied is 10 mg / m ^2, and the dispersion medium is dried to PET. Conductive fibers were arranged on the surface of the film to prepare a conductive film. A size of 10 mm × 10 mm was cut out from the central portion of this conductive film. Then, the cut-out conductive film is put on a silver paste on an SEM sample table having a 45 ° inclination (model number "728-45", manufactured by Nissin EM, inclined sample table 45 °, φ15 mm × 10 mm, made of M4 aluminum). It was attached flat to the surface of the table using. Further, Pt-Pd was sputtered for 20 to 30 seconds to obtain continuity.

<Example 1>
First, a 48 μm-thick polyethylene terephthalate film (trade name “Cosmo Shine (registered trademark) A4100”, manufactured by Toyobo Co., Ltd.) having a base layer on one side as a light-transmitting base material was prepared, and under the polyethylene terephthalate film. The composition 1 for the hard coat layer was applied to the formation side to form a coating film. Next, dry air at 50 ° C. was circulated through the formed coating film at a flow rate of 0.5 m / s for 15 seconds, and then dry air at 70 ° C. was further circulated at a flow rate of 10 m / s for 30 seconds for drying. The solvent in the coating film is evaporated by allowing the coating film to evaporate, and ultraviolet rays are irradiated so that the integrated light amount becomes 100 mJ / cm ² to cure the coating film, whereby a hard coat layer having a film thickness of 2 μm as a light transmissive functional layer. Was formed.

After forming the hard coat layer, the wall composition 1 (trade name "U-403B", manufactured by Chemitec Co., Ltd.) is placed on the untreated surface of the polyethylene terephthalate film opposite to the surface on which the hard coat layer is formed. Was applied by the flexographic printing method to form a coating film. Then, dry air at 40 ° C. was circulated for 15 seconds at a flow rate of 0.5 m / s to the formed coating film, and then dry air at 70 ° C. was further circulated for 30 seconds at a flow rate of 15 m / s for drying. The solvent in the coating film was evaporated. Then, by irradiating the coating film with ultraviolet rays so that the integrated light intensity was 100 mJ / cm ² , a plurality of electrically insulating wall portions having the shape shown in FIG. 2 were formed. The width of the wall portion was 30 μm, and the thickness of the wall portion was 1 μm.

After forming the plurality of wall portions, the conductive portion and the dummy conductive portion having the shapes shown in FIG. 2 were formed using the silver nanowire dispersion liquid 1. Specifically, first, the silver nanowire dispersion liquid 1 was filled between the walls by an inkjet method to form a coating film. Then, dry air at 40 ° C. was circulated through the formed coating film at a flow rate of 0.5 m / s for 15 seconds, and then dry air at 70 ° C. was further circulated at a flow rate of 15 m / s for 30 seconds to dry. The solvent in the coating film was evaporated. As a result, a conductive portion made of a dried coating film and a dummy conductive portion made of a dried coating film were formed on the surface of the polyethylene terephthalate film. The width of the line portion in the conductive portion was 0.5 mm, and the maximum width of the bulging portion was 4 mm. The thickness of the conductive portion was 0.1 μm.

The width of the wall was randomly measured at 10 points from the cross-sectional photograph of the wall taken with a scanning transmission electron microscope (STEM), and the maximum and minimum values were excluded from the 10 measured points. The arithmetic mean value of the width of 8 places was used. A specific cross-sectional photograph was taken by the following method. First, a sample for cross-section observation was prepared from the conductive film. Specifically, a conductive film cut out to a size of 2 mm × 5 mm was placed in a silicone-based embedding plate, an epoxy-based resin was poured into the conductive film, and the entire conductive film was embedded with the resin. Then, the embedded resin was left at 65 ° C. for 12 hours or more to be cured. Then, using an ultramicrotome (product name “Ultramicrotome EM UC7”, manufactured by Leica Microsystems, Inc.), the delivery thickness was set to 100 nm to prepare an ultrathin section. The prepared ultrathin section was collected by a mesh with a collodion membrane (150) and used as a sample for STEM. Then, a cross-sectional photograph of a sample for STEM was taken using a scanning transmission electron microscope (STEM) (product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation). At the time of taking this cross-sectional photograph, the detector (selection signal) was set to "TE", the acceleration voltage was set to 30 kV, and the emission was set to "10 μA". The magnification was adjusted appropriately at 5000 to 200,000 times while observing whether each layer could be distinguished by adjusting the focus. The preferred magnification is 10,000 to 50,000 times, more preferably 25,000 to 40,000 times. If the magnification is increased too much, the pixels at the interface become coarse and difficult to understand. Therefore, it is better not to increase the magnification too much when measuring the thickness of the wall portion. When taking a cross-sectional photograph, the beam monitor aperture was set to 3, the objective lens aperture was set to 3, and W. D. Was set to 8 mm. The line thicknesses of the conductive portion and the second conductive portion were measured by this method not only in Example 1 but also in all subsequent Examples and Comparative Examples.

The thickness of the wall was randomly measured at 10 points from the cross-sectional photograph of the wall taken with a scanning transmission electron microscope (STEM), and the maximum and minimum values were excluded from the 10 measured points. The arithmetic mean value of the thickness at 8 points was used. The cross-sectional photograph when measuring the thickness of the wall portion was taken under the same conditions as the cross-sectional photograph when measuring the width of the wall portion.

The thickness of the conductive part was randomly measured at 10 points from a cross-sectional photograph of the conductive part taken with a scanning transmission electron microscope (STEM), and the maximum and minimum values were excluded from the measured 10 points. The arithmetic mean value of the thickness at 8 points was used. The cross-sectional photograph when measuring the thickness of the conductive portion was taken under the same conditions as the cross-sectional photograph when measuring the width of the wall portion.

<Example 2>
In Example 2, a conductive film was obtained in the same manner as in Example 1 except that the width of the wall portion was 100 μm.

<Comparative example 1>
In Comparative Example 1, a conductive film was obtained in the same manner as in Example 1 except that the silver nanowire dispersion liquid 1 was applied using a bar coater and then wet-etched. Specifically, first, the silver nanowire dispersion liquid 1 is applied to the entire surface of the polyethylene terephthalate film using a bar coater on the untreated surface opposite to the surface on which the hard coat layer is formed in the polyethylene terephthalate film. A coating film was formed.

Next, dry air at 40 ° C. was circulated through the formed coating film at a flow rate of 0.5 m / s for 15 seconds, and then dry air at 70 ° C. was further circulated at a flow rate of 15 m / s for 30 seconds to dry. The solvent in the coating film was evaporated. As a result, a dried conductive portion was formed on the surface of the polyethylene terephthalate film.

After forming the conductive layer, the silver nanowires existing in the region corresponding to the wall portion of the conductive film according to Example 1 are wetted with an etching solution (product name "SEA-NW01", manufactured by Kanto Chemical Co., Inc.). The conductive portion was patterned by removing it by etching. As a result, a conductive film having a conductive portion and a dummy conductive portion was obtained.

<Electrical short-circuit evaluation>
The electrical short circuit of the conductive film according to Examples and Comparative Examples was evaluated. Specifically, first, in a sample cut out to a size of 50 mm × 50 mm so that two sides facing each other in the direction in which the conductive portion extends from the conductive film are aligned, a tester (product name “Digital MΩ Hister 3454-11”” , Hioki Electric Co., Ltd.) was used to evaluate whether or not a current flows between the conductive portion and the dummy conductive portion adjacent to the conductive portion. Then, a durability test was conducted in which a voltage of 32 V was applied to one of the conductive parts of the sample for 100 hours in an environment of 65 ° C. and 95% relative humidity. After the durability test, a tester (product name "Digital MΩ Hister 3454-11", manufactured by Hioki Electric Co., Ltd.) is used to evaluate whether or not a current flows through the conductive part and the dummy conductive part adjacent to the conductive part. By doing so, it was evaluated whether or not there was an electrical short circuit. The evaluation criteria are as follows.
◯: No current flowed between the conductive part and the dummy conductive part not only before the durability test but also after the durability test.
X: No current flowed between the conductive part and the dummy conductive part before the durability test, but a current flowed between the conductive part and the dummy conductive part after the durability test.

<Measurement of line resistance>
In the conductive films according to Examples and Comparative Examples, the linear resistance values of the conductive portions were measured. Specifically, first, the conductive portions straddle the conductive portions at both ends in the longitudinal direction of the sample cut into a rectangular shape of 5 mm × 100 mm so that the conductive portion extends from the conductive film in the longitudinal direction. A linear silver paste extending in the width direction of the above (trade name "DW-520H-14", manufactured by Toyo Boseki Co., Ltd.) was applied. The silver paste was then cured by heating at 130 ° C. for 30 minutes. Then, the cured silver paste was irradiated with laser light under the following conditions to remove a part of the silver paste so that the dummy conductive portion did not electrically conduct with the conductive portion. In that state, in an environment of a temperature of 23 ° C. and a relative humidity of 50%, the probe terminal of the tester (product name "Digital MΩ Hister 3454-11", manufactured by Hioki Electric Co., Ltd.) is brought into contact with the conductive part of the cured silver paste. It was measured by contacting the part. Specifically, the Digital MΩ Hister 3454-11 has two probe terminals (red probe terminal and black probe terminal, both pin-shaped), so that the red probe terminal contacts one of the cured silver pastes. The black probe terminal was brought into contact with the other cured silver paste, and the linear resistance value of the conductive portion was measured. Then, the linear resistance value of the conductive portion was obtained from the above mathematical formula (3).
(Laser light irradiation conditions)
・ Type: YVO ₄
-Wavelength: 1064 nm
・ Pulse width: 8 to 10 ns
・ Frequency: 100kHz
・ Spot diameter: 30 μm
・ Pulse energy: 16μJ
-Processing speed: 1200 mm / sec

<Measurement of haze value>
In the conductive films according to Examples and Comparative Examples, JIS was used in an environment of a temperature of 23 ° C. and a relative humidity of 50% using a haze meter (product name "HM-150", manufactured by Murakami Color Technology Research Institute Co., Ltd.). The haze value (total haze value) of the conductive film was measured according to K7136: 2000. The haze value is a value measured for the entire conductive film, and after cutting into a size of 50 mm × 100 mm, there are no curls or wrinkles, and there are no fingerprints, dust, etc., Examples 1 to 5 In the conductive film according to Comparative Example 1, the measurement was performed by installing the film so that the conductive portion side was the non-light source side. The haze value was measured 5 times for one conductive film, and was taken as an arithmetic mean value of the values obtained by measuring 3 times excluding the maximum value and the minimum value.

<Flexibility evaluation>
(1) Evaluation of Electrical Resistance Value Ratio Before and After Folding Test (FD Test) The conductive film according to Examples 1 and 2 was subjected to a folding test to evaluate its flexibility. Specifically, first, one rectangular sample having a length of 125 mm and a width of 50 mm was cut out from the conductive film. Here, these samples were cut out so that the longitudinal direction of the samples was the direction in which the conductive portion extends (conducting direction). After cutting out the samples from the conductive film, apply silver paste (trade name "DW-520H-14", manufactured by Toyobo Co., Ltd.) to both ends of the surface in the longitudinal direction of each sample in a length of 10 mm and a width of 50 mm. Then, it was heated at 130 ° C. for 30 minutes to obtain a sample in which the cured silver paste was provided on both ends. The measurement distance of the electric resistance value in the sample provided with the cured silver paste at both ends was 105 mm, and the measurement width was 50 mm. After that, the cured silver paste is irradiated with a laser beam under the conditions described in the column of linear resistance value measurement, and as shown in FIG. 6, one of the silver pastes is used so that the dummy conductive portion does not electrically conduct with the conductive portion. The part was removed. Then, the electric resistance value of this sample was measured using a tester (product name "Digital MΩ Hister 3454-11", manufactured by Hioki Electric Co., Ltd.). Specifically, since the Digital MΩ Conductor 3454-11 has two probe terminals (a red probe terminal and a black probe terminal, both of which are pin-shaped), a red probe terminal is provided at one end. The electric resistance value was measured by contacting the portion of the cured silver paste that came into contact with the conductive portion and contacting the black probe terminal with the portion of the cured silver paste that came into contact with the conductive portion provided at the other end.

After that, as a folding durability tester, the short side (50 mm) side of this selected sample was fixed to a U-shaped expansion / contraction tester (product name "DLDMLH-FS", manufactured by Yuasa System Co., Ltd.) with fixing portions. , As shown in FIG. 7C, attach the two side portions facing each other so that the minimum distance between them is 3 mm (outer diameter of the bent portion is 3.0 mm), and under the following conditions, the conductive portion of this sample. A test of folding the side surface by 180 ° (a test of folding so that the conductive portion is on the inside and the base material is on the outside) was performed 100,000 times.
(Folding conditions)
・ Round trip speed: 80 rpm (revolutions per minute)
・ Test stroke: 60 mm
・ Bending angle: 180 °

After the folding test, the electric resistance value of the surface of the conductive portion was measured in the sample after the folding test in the same manner as the sample before the folding test. Then, the electric resistance value ratio (the electric resistance value of the sample after the selected folding test / before the folding test), which is the ratio of the electric resistance value of the sample after the folding test to the electric resistance value of the sample before the selected folding test. The electrical resistance of the sample) was determined. Further, a new sample cut from the conductive film according to Examples 1 and 2 in the same manner as described above and selected by measuring the electric resistance value in the same manner is attached to the above-mentioned durability tester in the same manner as described above. A test in which the surface of the sample on the substrate side is folded 180 ° (a test in which the conductive portion is on the outside and the substrate is on the inside) is performed 100,000 times, and similarly, the surface of the conductive portion of the sample after the folding test is performed. The electrical resistance value of was measured to determine the electrical resistance value ratio. Then, the result of the folding test was evaluated according to the following criteria. The electrical resistance value ratio was measured 5 times and used as the arithmetic mean value of the values obtained in 3 measurements excluding the maximum value and the minimum value out of the 5 times.
⊚: In all the folding tests, the electric resistance value ratio was 1.5 or less.
◯: In all the folding tests, the electric resistance value ratio exceeded 1.5 and was 3 or less.
X: In any of the folding tests, the electrical resistance value ratio exceeded 3.

(2) Evaluation of Folding Habit after Folding Test In the conductive films according to Examples 1 and 2, the appearance after the folding test was observed to evaluate whether or not a bending habit was generated at the bent portion of the conductive film. The folding test was performed by the method described in the column of surface resistance evaluation before and after the folding test. The folds were observed visually in an environment of a temperature of 23 ° C. and a relative humidity of 50%. When observing folding habits, in a bright room with white lighting (800 lux to 2000 lux), the bent part is evenly observed by transmitted light and reflected light, and the part that was inside the bent part when folded and Both parts that were outside were observed. In observing folding habits, the sample before the folding test is placed on the fixed part of the durability tester so that the position to be observed can be easily grasped, and when folded once, as shown in FIG. An oil-based pen was used to mark both ends of the bent portion in a direction orthogonal to the folding direction to indicate that the bent portion was a bent portion. Further, after the folding test, in a state of being removed from the durability tester after the folding test, a line connecting the marks at both ends of the bent portion was drawn with an oil-based pen. Then, in observing the bending habit, the entire bent portion, which is a region formed by the marks at both ends of the bent portion and the line connecting the marks, was visually observed. When the region serving as the bent portion of each conductive film was observed before the folding test, no folding habit was observed. The evaluation criteria were as follows.
◯: No folding habit was observed on the conductive film even after the folding test.
Δ: After the folding test, some folding habits were observed on the conductive film, but the level was not a problem in actual use.
X: After the folding test, folding habits were clearly observed on the conductive film.

(3) Evaluation of Microcracks After Folding Test In the conductive films according to Examples 1 and 2, the appearance after the folding test was observed to evaluate whether microcracks were generated at the bent portion of the conductive film. The folding test was performed by the method described in the column of surface resistance evaluation before and after the folding test. Observation of microcracks was performed using a digital microscope (product name "VHX-5000", manufactured by KEYENCE CORPORATION) in an environment of a temperature of 23 ° C. and a relative humidity of 50%. Specifically, first, the sample after the folding test was slowly spread, and the sample was fixed to the stage of the microscope with tape. At this time, if the crease is strong, the observation portion should be as flat as possible. However, do not touch the planned observation part (bent part) near the center of the sample with your hands, and do not apply any force. Next, both the inner part and the outer part when folded were observed. The observation of the microcracks was performed in a dark field and reflected light at a magnification of 200 times by selecting ring illumination as the illumination of the digital microscope. In observing microcracks, as shown in FIG. 8, when the sample before the folding test is installed in the fixed part of the durability tester and folded once so that the position to be observed can be easily grasped. An oil-based pen was used to mark both ends of the bent portion in a direction orthogonal to the folding direction to indicate that the bent portion was a bent portion. Further, after the folding test, in a state of being removed from the durability tester after the folding test, a line connecting the marks at both ends of the bent portion was drawn with an oil-based pen. Then, in observing the microcracks, the position of the scope was adjusted so that the center of the scope field of view was the center of the bent portion. When the region serving as the bent portion of each conductive film was observed before the folding test, no microcracks were observed. The evaluation criteria were as follows.
(Micro crack)
◯: No microcracks were observed in the conductive film even after the folding test.
Δ: After the folding test, some microcracks were observed in the conductive film, but the level was not a problem in actual use.
X: After the folding test, microcracks were clearly observed on the conductive film.

The results are shown in Table 1 below.

As shown in Table 1, in the conductive film according to Comparative Example 1, an electrical short circuit occurred between the conductive portion and the dummy conductive portion after the durability test. It is considered that this is because the silver ions in the conductive portion and the dummy conductive portion migrated by the durability test and precipitated from the conductive portion and the dummy conductive portion. On the other hand, in the conductive films according to Examples 1 and 2, since an electrically insulating wall portion was formed between the conductive portion and the dummy conductive portion, the conductive portion was electrically connected before and after the durability test. No short circuit occurred. It is considered that this is because the silver ions in the conductive portion migrated in the durability test and the silver ions were blocked by the wall portion even when the silver ions were precipitated from the conductive portion or the dummy conductive portion.

In the conductive film according to Comparative Example 1, since it was wet-etched, the silver nanowires in the removed portion were wasted. On the other hand, in the conductive film according to Examples 1 and 2, since the silver nanowire dispersion liquid is filled between the wall portions, the conductive portion directly formed into a desired shape can be obtained without wasting the silver nanowires. Was made.

Regarding the fiber diameter of the silver nanowires of the conductive films according to Examples 1 and 2, when each conductive film was observed with a scanning electron microscope (SEM) as follows, the results obtained from the above composition were obtained. Although there was a deviation of about 1 to 2 nm, it was almost the same.

Using the SEM function of a scanning electron microscope (SEM) (product name "S-4800 (TYPE2)", manufactured by Hitachi High-Technologies Corporation), 10 images were taken at 10,000 to 20 million times, and the attached software was used. The fiber diameters of 100 conductive fibers were measured on the imaging screen, and the fiber diameters of 98 conductive fibers excluding the maximum and minimum values among the 100 fibers were calculated as the arithmetic mean value. When measuring the fiber diameter, use a sample table with a 45 ° inclination, signal selection is "SE", acceleration voltage is "3kV", emission current is "10μA to 20μA", and SE detector is "mixed". , Probe current is "Norm", focus mode is "UHR", condenser lens 1 is "5.0", W. D. Was set to "8 mm" and Til was set to "30 °". Since the TE detector is not used during SEM observation, be sure to remove the TE detector before SEM observation. The S-4800 can select the STEM function and the SEM function, but the SEM function is used when measuring the fiber diameter.

10 ... Conductive film 10A ... Front surface 10B ... Back surface 11 ... Light-transmitting base material 12 ... Wall part 13 ... Conductive part 14 ... Dummy conductive part 15 ... Light-transmitting functional layer 16 ... Conductive fiber 40 ... Image display device 50 ... Display element 70 ... Touch panel

Claims (9)

A method for producing a conductive film including a light-transmitting base material and a conductive portion arranged on the first surface side of the light-transmitting base material.
A step of forming two or more electrically insulating walls separated from each other on the first surface side of the light-transmitting base material, and
A step of filling a conductive fiber dispersion liquid containing conductive fibers between the wall portions to form a conductive portion.
A method for producing a conductive film. The method for producing a conductive film according to claim 1, wherein the wall portion contains a resin. A conductive film comprising a light-transmitting base material and a conductive portion arranged on the first surface side of the light-transmitting base material.
Two or more electrically insulating walls are provided on the first surface side of the light-transmitting base material and are separated from each other.
A conductive film in which the conductive portion contains conductive fibers and is filled between the wall portions. The conductive film according to claim 3, wherein the thickness of the wall portion is larger than the thickness of the conductive portion. The conductive film according to claim 3 or 4, wherein the width of the wall portion is 5 μm or more and 500 μm or less. A dummy conductive portion containing conductive fibers and electrically insulated from the conductive portion is further provided.
The conductive film according to any one of claims 3 to 5, wherein the dummy conductive portion is filled between the wall portions different from the conductive portion. A sensor comprising the conductive film according to any one of claims 3 to 6. A touch panel comprising the conductive film according to any one of claims 3 to 6. An image display device comprising the conductive film according to any one of claims 3 to 6 or the touch panel according to claim 8.

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