WO2015072321A1

WO2015072321A1 - Transparent conductive laminate and touch panel

Info

Publication number: WO2015072321A1
Application number: PCT/JP2014/078571
Authority: WO
Inventors: 和久吉岡; 正行森野; 富田　倫央
Original assignee: 旭硝子株式会社
Priority date: 2013-11-14
Filing date: 2014-10-28
Publication date: 2015-05-21
Also published as: JPWO2015072321A1; TW201528291A; CN105723473A

Abstract

Provided is a transparent conductive laminate obtained by laminating a transparent conductive film on a base, wherein adhesion between the base and the transparent conductive film is ensured, while maintaining the electrical characteristics of the transparent conductive film. This transparent conductive laminate has good light transmittance characteristics and excellent chemical resistance. Also provided is a highly reliable touch panel which is provided with this transparent conductive laminate. A transparent conductive laminate which comprises a transparent base, an SiO_x1 layer (wherein x1 is 1.8 or more but less than 2.0) that is provided on one main surface of the transparent base and has a thickness of 3-60 nm, an SiO_x2 layer (wherein x2 is from 1.9 to 2.0 (inclusive) and larger than x1) that is provided on the SiO_x1 layer and has a thickness of 0.2-5 nm, and a conductive layer that is provided on the SiO_x2 layer and is mainly formed of an indium tin oxide; and a touch panel which is provided with this transparent conductive laminate.

Description

Transparent conductive laminate and touch panel

The present invention relates to a transparent conductive laminate and a touch panel having the same.

A transparent conductive laminate in which a transparent conductive film is laminated on a transparent substrate has conductivity and optical transparency, so that a transparent electrode film, an electromagnetic wave shielding film, a planar heating film, an antireflection film, etc. In recent years, it has attracted attention as a touch panel electrode. There are various types of touch panels such as a resistive film type, a capacitive coupling type, and an optical type. The transparent conductive film is used in, for example, a resistance film type that identifies a touch position by contacting upper and lower electrodes, and a capacitive coupling method that senses a change in capacitance. The transparent conductive film used for the resistance film type is required to have high durability because the transparent conductive films are in mechanical contact with each other on the principle of operation.

In order to impart such high durability to a transparent conductive laminate used as a transparent conductive film, a base material is conventionally provided by providing a silicon oxide layer between the base material and a transparent conductive film such as indium tin oxide. Reinforcing the adhesion of the transparent conductive film to the surface has been performed. Here, when the SiO ₂ layer is used as the silicon oxide layer, the adhesion can be improved to some extent, but the chemical resistance such as adhesion and alkali resistance is not sufficient, and the required durability is satisfied. I couldn't say. In addition, when a SiO _x (x is less than 2) layer is used, although high adhesion is obtained, there is a problem in that the surface electric resistance of the transparent conductive film is changed.

Therefore, in order to achieve both the adhesion and the maintenance of the electrical characteristics of the transparent conductive film, for example, in Patent Document 1, SiO _x (x is 1) having a relative refractive index in the range of 1.6 to 1.9 from the substrate side. .5 or more and less than 2) layer, and a SiO ₂ layer in that order, and a transparent conductive laminate having a transparent conductive film thereon is described. However, in the transparent conductive laminate described in Patent Document 1, although adhesion and maintenance of electrical characteristics in the transparent conductive film can be both achieved, there may be a change in the color tone of transmitted light. Since the thickness is large, improvement in productivity and light transmittance has been desired.

Japanese Patent No. 4508074

The present invention provides a transparent conductive laminate in which a transparent conductive film is laminated on a base material, the adhesion between the base material and the transparent conductive film is ensured, and the electrical characteristics of the transparent conductive film are maintained, and further the light transmission characteristics It aims at providing the transparent conductive laminated body which is favorable and is excellent in chemical resistance. Furthermore, this invention aims at provision of the highly reliable touch panel provided with the above-mentioned transparent conductive laminated body.

The transparent conductive laminate of the present invention comprises a transparent substrate and a SiO _x1 layer having a thickness of 3 to 60 nm provided on one main surface of the transparent substrate (where x1 is 1.8 or more and 2. less than 0 is. a), _{SiO x2} layer of the thickness provided on _{SiO x1} layer on the 0.2 ~ 5 nm (although, x2 is 1.9 to 2.0, and greater than x1. And a conductive layer mainly composed of indium tin oxide provided on the SiO _x2 layer.
Moreover, the touch panel of this invention is equipped with the transparent conductive laminated body of the said invention.

According to the present invention, in the transparent conductive laminate in which the transparent conductive film is laminated on the base material, the adhesion between the base material and the transparent conductive film is ensured, the electrical characteristics of the transparent conductive film are maintained, and the light A transparent conductive laminate having good transmission characteristics and excellent chemical resistance can be provided. Furthermore, according to this invention, the reliable touch panel provided with the above-mentioned transparent conductive laminated body can be provided.

It is sectional drawing which shows an example of embodiment of the transparent conductive laminated body of this invention. It is sectional drawing which shows another example of embodiment of the transparent conductive laminated body of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is limited to the following description and is not interpreted.

[Transparent conductive laminate]
1 and 2 are cross-sectional views showing an example of an embodiment of the transparent conductive laminate of the present invention and another example, respectively.

1 and 2, the transparent conductive laminate 10 includes a transparent substrate 1 and a SiO _x1 layer 2 (provided that x1 is provided on one main surface of the transparent substrate 1 and has a thickness of 3 to 60 nm). Is 1.8 or more and less than 2.0), and the SiO _x2 layer 3 having a thickness of 0.2 to 5 nm provided on the SiO _x1 layer 2 (where x2 is 1.9 or more and 2.0 or less) And larger than x1), and a conductive layer 4 mainly composed of indium tin oxide provided on the SiO _x2 layer 3.

In the transparent conductive laminate 10 shown in FIG. 2, the transparent substrate 1 has

resin layers

5a and 5b on both main surfaces, and the SiO _x1 layer 2, the SiO _x2 layer 3, and the conductive layer on one resin layer 5a. Reference numeral 4 denotes a configuration provided in that order. In the transparent conductive laminate of the present invention, resin layers such as the

resin layers

5a and 5b shown in FIG. 2 are layers provided arbitrarily.

The conductive layer 4 is formed on the transparent base material 1 via the SiO _x1 layer 2 and the SiO _x2 layer 3 having the above-described configuration, thereby being in close contact with the transparent base material 1 and having high durability. In addition, the conductive layer 4 mainly composed of indium tin oxide can be formed in the same crystalline state as that formed directly on the transparent substrate 1 by being formed in contact with the SiO _x2 layer 3. Thereby, the electrical characteristics such as the sheet resistance value can be maintained at a predetermined value in the conductive layer 4. The transparent conductive laminate 10 has good light transmission characteristics such as high visible light transmittance and little change in color tone of transmitted light.
Hereinafter, each element which comprises the transparent conductive laminated body 10 is demonstrated.

As the transparent substrate 1, a transparent substrate usually used for a transparent conductive laminate, for example, a film-like or plate-like substrate made of a highly transparent material can be used without particular limitation. Examples of such transparent substrate 1 include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon 6 and nylon 66, polyimide, polyarylate, polycarbonate, and poly A plastic film made of a polymer or copolymer selected from (meth) acrylate, polyethersulfone, polysulfone and the like is preferable. The plastic film may be a stretched film or an unstretched film. Among these, a plastic film made of polyethylene terephthalate is particularly preferable as the transparent substrate 1.

In this specification, “(meth) acrylate” is used as a general term for acrylate and methacrylate. Hereinafter, “(meth) acryl ...” is used in the same meaning as described above.

The thickness of the transparent substrate 1 is appropriately selected depending on the use for which the transparent conductive laminate 10 is used. When used for a touch panel, the thickness of the transparent substrate 1 is preferably 10 to 200 μm, more preferably 20 to 150 μm, from the viewpoint of flexibility and durability.

In addition, at least the main surface of the transparent substrate 1 on the side where the SiO _x1 layer 2 is disposed is previously subjected to an easy adhesion treatment, a plasma treatment, a corona for the purpose of improving adhesion to the SiO _x1 layer 2 and the like. Surface treatment such as treatment may be performed. The surface treatment may be performed on both main surfaces of the transparent substrate 1.

Furthermore, the transparent substrate 1 may have a resin layer on at least the main surface on the side where the SiO _x1 layer 2 is disposed as long as the effect of the present invention is not impaired. The resin layer may be provided on both main surfaces of the transparent substrate 1. FIG. 2 shows a cross-sectional view of the transparent conductive laminate 10 having the

resin layers

5a and 5b on both main surfaces of the transparent substrate 1 as described above. As the resin layer, a resin layer having a function of improving the adhesion of the SiO _x1 layer 2 or a function of optical adjustment or a hard coat layer which is a transparent and hard resin layer is preferable.

The thickness of the hard coat layer is preferably 1 to 15 μm, more preferably 1.5 to 10 μm. By setting the film thickness of the hard coat layer to 1 μm or more, it is possible to obtain the expected effect due to the formation of the hard coat layer. Further, by setting the film thickness to 15 μm or less, it is possible to suppress a decrease in the film formation efficiency of the hard coat layer and to suppress the occurrence of cracks.

The hard coat layer is made of, for example, a cured product of a curable resin that is cured by ionizing radiation or heat. The curable resin cured by ionizing radiation may include an acrylic material, a polyfunctional (meth) acrylate compound such as a (meth) acrylic acid ester of a polyhydric alcohol, diisocyanate, a polyhydric alcohol, and (meth) acrylic. A polyfunctional urethane (meth) acrylate compound synthesized from a hydroxy ester of an acid or the like can be used. In addition to these, polyether resins, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins having an acrylate functional group, for example, a (meth) acryloyl group can be used. A thermosetting polysiloxane resin or the like can also be used.

As a method for applying the curable resin to the application surface of the transparent substrate, a wet film forming method is preferable, and a roll coater, a reverse roll coater, a gravure coater, a micro gravure coater, a knife coater, a bar coater, a wire bar coater, and a die coater. And a coating method using a dip coater is preferred.

As the ionizing radiation used for curing the curable resin, for example, ultraviolet rays and electron beams can be used. In the case of ultraviolet curing, a light source such as a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, or a xenon arc can be used. In the case of electron beam curing, electron beams emitted from various electron beam accelerators such as cockloftwald type, bandegraph type, resonant transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type can be used. .

The SiO _x1 layer 2 (where x1 is 1.8 or more and less than 2.0) is a layer having a thickness of 3 to 60 nm disposed on one main surface of the transparent substrate 1. The SiO _x1 layer 2 is formed through the resin layer when the transparent substrate 1 has a resin layer such as the hard coat layer as shown in FIG. 2, for example, in the case of FIG. It arrange | positions through one resin layer 5a of the resin layers 5a and 5b arrange | positioned on the main surface. As shown in FIG. 1, when the transparent substrate 1 does not have a resin layer, the SiO _x1 layer 2 is directly disposed on the transparent substrate 1.

If the thickness of x1 and SiO _x1 layer 2 in SiO _x1 of SiO _x1 layer 2 is in the above range, the transparent conductive multilayer body obtained, have good light transmission characteristics with sufficient adhesion can be obtained between each layer Yes, and alkali resistance is also good.

Furthermore, when the transparent conductive laminate is used in various applications, and the transparent conductive laminate and the electro-optic element are in contact with each other, the transparent conductive laminate has a good gas barrier against water vapor, oxygen, and the like. Sex is required. If x1 and the thickness of the _{SiO x1} layer 2 in _{SiO x1} of SiO _x1 layer 2 is in the above range, gas barrier properties also good while ensuring the adhesion.

The gas barrier property of the transparent conductive laminate can be evaluated by using, for example, the water vapor permeability measured by the following method as an index for the water vapor barrier property. That is, if the water vapor permeability is lower than a predetermined value, it can be said that the water vapor barrier property is excellent. The water vapor transmission rate can be measured by a moisture permeability test (cup method) defined in JIS Z0208 or an infrared sensor method defined in JIS K7129 B method. The water vapor permeability of the transparent conductive laminate is preferably 1 g / m ² / day or less as the water vapor permeability measured at a temperature of 40 ° C. and a humidity of 90% RH based on JIS K7129 B method, and 0.5 g / m ² / day or less is more preferable.

Further, from these viewpoints, x1 in the _{SiO x1} of _{SiO x1} layer 2 is preferably in the range of less than 2.0 A and 1.9 or more at x2 smaller value in _{SiO x2.} The thickness of the SiO _x1 layer 2 is preferably 3 to 10 nm, and more preferably 4 to 7 nm.

The method for forming the SiO _x1 layer 2 on the main surface of the transparent substrate 1 is not particularly limited as long as the SiO _x1 layer having the above thickness is formed. It may be a dry film forming method or a wet film forming method. The SiO _x1 layer 2 is usually formed by a dry film forming method having excellent heat and heat resistance. As the dry film forming method, a sputtering method, an ion plating method, or a vacuum deposition method is preferable, and a sputtering method is particularly preferable.

When the sputtering method is applied, it is preferable to use a boron-doped polysilicon target as the sputtering target. For example, the SiO _x1 layer 2 is formed by sputtering a boron-doped polysilicon target at a pressure of 0.1 to 0.8 Pa while introducing a mixed gas obtained by mixing an oxygen gas into an argon gas into the sputtering apparatus. Yes. In the sputtering, by adjusting the power density and sputtering time, the thickness of the SiO _x1 layer 2 can be adjusted to a predetermined thickness within the above range, and x1 can be adjusted by the voltage and the oxygen gas flow rate.

In the SiO _x1 layer 2 thus obtained, the refractive index of SiO _x1 with respect to light having a wavelength of 550 nm is preferably approximately in the range of 1.43 to 1.55, and more preferably 1.46 to 1.53. Hereinafter, the refractive index refers to the refractive index with respect to light having a wavelength of 550 nm unless otherwise specified. The refractive index of the _{SiO x1} in _{SiO x1} layer 2 may vary under the influence when further forming the _{SiO x2} layer 3 on the _{SiO x1} layer 2. In this specification, the refractive index of _{SiO x1} in _{SiO x1} layer, the transparent substrate 1 is formed on, refers to refractive index of the _{SiO x1} in _{SiO x1} layer in a state where nothing is formed thereon.

The SiO _x2 layer 3 disposed on the SiO _x1 layer 2 has a thickness of 0.2 to 5 nm, _x2 in the SiO x2 is 1.9 or more and 2.0 or less, and x2 is larger than x1. Is a layer.
If the thickness of x2 and SiO _x2 layer 3 in SiO _x2 of SiO _x2 layer 3 is in the above range, the transparent conductive laminate obtained, light transmission characteristic is good with sufficient adhesion can be obtained between each layer Become. Furthermore, the film-forming property of the conductive layer 4 mainly composed of indium tin oxide formed on the SiO _x2 layer 3 can be equivalent to that when directly forming the film on the transparent substrate 1. Electrical characteristics can be made sufficient.

Further, from these viewpoints, x2 in _{SiO x2} of _{SiO x2} layer 3 is preferably in the range of a by 1.95 to 2.0 is greater than x1 in _{SiO x1,} 2.0 is more preferable. The thickness of the SiO _x2 layer 3 is preferably 0.5 to 5 nm, more preferably 1 to 3 nm.

Here, in the transparent conductive laminate 10, the total thickness of the SiO _x1 layer 2 and the SiO _x2 layer 3 is preferably 20 nm or less, and more preferably 10 nm or less. When the total thickness of the SiO _x1 layer 2 and the SiO _x2 layer 3 is in this range, the light transmission characteristics in the transparent conductive laminate 10 are further improved. That is, in the transparent conductive laminate 10, it is possible to achieve light transmission characteristics that have high visible light transmittance and little change in the color tone of transmitted light. Moreover, it is advantageous also in terms of productivity when the total thickness of the SiO _x1 layer 2 and the SiO _x2 layer 3 is in the above range.

The color tone of transmitted light can be evaluated using the value of b * in the L * a * b * display color system using a C light source based on JIS Z8729 (2004) as an index. The value of b * is used as a yellowness index. In this specification, the value of b * in the L * a * b * display color system using a C light source based on JIS Z8729 (2004) is simply referred to as “b * value”. In the transparent conductive laminate of the present invention, the value of b * is preferably 1.5 or less.

The method of forming the SiO _x2 layer 3 is not particularly limited as long as the SiO _x2 layer having the above thickness is formed. It may be a dry film forming method or a wet film forming method. The SiO _x2 layer 3 is usually formed by a dry film forming method having excellent heat and heat resistance. As the dry film forming method, a sputtering method, an ion plating method, or a vacuum deposition method is preferable, and a sputtering method is particularly preferable.

When the sputtering method is applied, it is preferable to use a boron-doped polysilicon target as the sputtering target. The film formation of the SiO _x2 layer 3 is performed, for example, by sputtering a boron-doped polysilicon target at a pressure of 0.1 to 0.8 Pa while introducing a mixed gas obtained by mixing oxygen gas into argon gas into the sputtering apparatus. Yes. In the sputtering, the thickness of the SiO _x2 layer 3 is adjusted to a predetermined thickness within the above range by adjusting the power density and the sputtering time. Further, x2 is adjusted by adjusting the voltage and the oxygen gas flow rate.

In the SiO _x2 layer 3 thus obtained, the refractive index of SiO _x2 with respect to light having a wavelength of 550 nm is preferably in the range of about 1.46 to 1.54, more preferably 1.47 to 1.52. The refractive index of the _{SiO x2} in _{SiO x2} layer, similar to the refractive index of _{SiO x1} in the _{SiO x1} layer, is formed on the _{SiO x1} layer, the _{SiO x2} layer in a state where nothing is formed thereon It refers to the refractive index of SiO _x2 .

When the refractive index of SiO _x1 described above is compared with the refractive index of SiO _x2 , it can be seen that the difference is small. Since the refractive index difference between SiO _x1 and SiO _x2 is small, reflection at the interface between the SiO _x1 layer 2 and the SiO _x2 layer 3 is suppressed, and the value of b * in the transparent conductive laminate can be suppressed low.

As the conductive layer 4 mainly composed of indium tin oxide provided on the SiO _x2 layer 3, a layer mainly composed of indium tin oxide used in the transparent conductive laminate is used as the transparent conductive film without any particular limitation. .

In the transparent conductive laminate of the present invention, for example, an amorphous layer mainly composed of amorphous indium tin oxide is laminated on the SiO _x2 layer 3, and then the amorphous layer is subjected to heat treatment ( It is preferable to use as the conductive layer 4 a crystalline transparent conductive film obtained by crystallization by annealing. Hereinafter, the conductive layer 4 thus formed will be described. In the following description, an amorphous layer mainly composed of amorphous indium tin oxide is simply referred to as an “amorphous layer”.

Here, for amorphous and crystalline, the resistance value change rate obtained by measuring the resistance value before and after immersing in an HCl solution (concentration 1.5 mol / L) for 5 minutes, specifically, Resistance value / resistance value before immersion) × 100 (%) It is evaluated by a resistance value change rate obtained by (%). When this resistance value change rate exceeds 200%, it is evaluated as amorphous, and when the resistance value change rate is 200% or less, it is evaluated as crystalline.

The indium tin oxide mainly constituting the amorphous layer or the conductive layer 4 crystallized therefrom is indium and tin oxide. Examples of the oxide include a mixture of indium oxide and tin oxide, indium oxide and oxide. A composite oxide of tin is included. The composition of indium tin oxide does not change both in the amorphous state and in the crystallized state.

The content of tin in the indium tin oxide used in the present invention is preferably 5.5 to 10% by mass in terms of SnO ₂ . Hereinafter, the content of tin in oxide tin conversion (SnO ₂ conversion) may be referred to as tin oxide content. The tin oxide content in the indium tin oxide is preferably 5.8% by mass or more, more preferably more than 6% by mass, and even more preferably 6.5% by mass or more. In addition, the content is preferably 8.9% by mass or less, more preferably 8.5% by mass or less, and further preferably 8.3% by mass or less. When the content of tin oxide in the indium tin oxide is in the above range, crystallization by heat treatment from the amorphous state is easy, the sheet resistance value when crystallized is low, and the increase in film thickness is also suppressed. It can be done.

The conductive layer 4 is a layer mainly composed of indium tin oxide. The phrase “consisting mainly of indium tin oxide” specifically means that the content ratio of indium tin oxide in the conductive layer 4 is 90% by mass or more. That is, the amorphous layer or the conductive layer 4 may contain a component other than indium tin oxide within a range of 10% by mass or less as necessary and within the limits not departing from the spirit of the present invention. Examples of components other than indium tin oxide include oxides such as aluminum, zirconium, gallium, silicon, tungsten, zinc, titanium, magnesium, cerium, and germanium. The content of components other than these indium tin oxides in the amorphous layer or the conductive layer 4 is preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 1% by mass or less. The amorphous layer or the conductive layer 4 is particularly preferably made of only indium tin oxide.

Here, the amorphous layer mainly composed of indium tin oxide and the conductive layer 4 have substantially the same thickness. The thickness of the conductive layer 4 is preferably 10 to 50 nm, more preferably 15 to 35 nm, from the viewpoints of ease of crystallizing the amorphous layer by heat treatment and optical properties such as transmittance.

The conductive layer obtained by crystallizing the amorphous layer mainly composed of indium tin oxide has been described above. However, in the transparent conductive laminate of the present invention, indium tin laminated as described above is necessary. An amorphous layer mainly composed of an oxide may be used as a conductive layer in an unheated state to form a transparent conductive laminate.

When an amorphous layer mainly composed of indium tin oxide is crystallized by heat treatment to form a conductive layer, the sheet resistance value of the amorphous layer used is 200 to 500Ω / □ is preferable, and 300 to 450Ω / □ is more preferable. The sheet resistance value of the conductive layer obtained by crystallizing such an amorphous layer mainly composed of indium tin oxide is preferably 50 to 200Ω / □, and more preferably 70 to 160Ω / □.

The sheet resistance value of the conductive layer in the transparent conductive laminate of the present invention is preferably 50 to 500Ω / □, and preferably 70 to 450Ω from the viewpoint of suppressing a decrease in transmission speed during operation accompanying an increase in the size of an electronic device such as a touch panel. / □ is more preferable. Moreover, according to such a thing, etching property can also be made favorable. The range of the sheet resistance value of the preferable conductive layer includes the sheet resistance value of the amorphous layer that is converted into the conductive layer by the heat treatment described above. Therefore, in the transparent conductive laminate of the present invention, the amorphous layer itself can be used as a conductive layer.

In order to form the conductive layer 4 in which an amorphous layer mainly composed of indium tin oxide is crystallized, first, a non-crystalline state mainly composed of indium tin oxide in an amorphous state is formed on the SiO _x2 layer 3 described above. A crystalline layer is formed. The film forming method is not necessarily limited, but a sputtering method, an ion plating method, or a vacuum evaporation method is preferable, and a sputtering method is particularly preferable.

When applying the sputtering method, it is preferable to use a sputtering target made of a sintered body of indium tin oxide obtained by mixing and sintering tin oxide (SnO ₂ ) and indium oxide (In ₂ O ₃ ). For forming the amorphous layer, the sputtering target is used, for example, a mixed gas in which 0.5 to 10% by volume, preferably 0.8 to 6% by volume of oxygen gas is mixed with argon gas in the sputtering apparatus. Sputtering is preferably performed while being introduced into the substrate. By performing sputtering while introducing such a mixed gas, it is possible to form an amorphous layer that is amorphous, easy to crystallize by heat treatment, and low in sheet resistance when crystallized. .

Prior to the formation of the amorphous layer, the degree of vacuum in the sputtering apparatus is evacuated to 5 × 10 ⁻⁴ Pa or less, preferably 9 × 10 ⁻⁵ Pa or less, so that moisture or a transparent substrate in the sputtering apparatus is evacuated. It is preferable to have an atmosphere from which impurities such as moisture or organic gas generated from the material are removed. By reducing the presence of moisture and organic gas during film formation, crystallization by heat treatment is easy, and a sheet having a low sheet resistance when crystallized can be easily obtained.

The flow rate of the oxygen gas when forming the amorphous layer is preferably in the range of 0.6 to 1.4 times the flow rate when the sheet resistance value after crystallization becomes the minimum value, and 0.7 The range of -1.3 times is more preferable, and the range of 0.8-1.2 times is particularly preferable. Therefore, in the actual film formation of the amorphous layer, the flow rate of the oxygen gas when the sheet resistance value after crystallization becomes the minimum value in this way is obtained in advance, It is preferable to adjust the flow rate of the oxygen gas so as to be within the range. Since the optimum flow rate varies slightly depending on the film forming apparatus, an amorphous layer having a low sheet resistance value after crystallization can be effectively formed particularly by such a method.

The sheet resistance value of the amorphous layer thus formed is generally within the preferred range of the above-described amorphous layer, and the amorphous layer itself obtained without performing the following heat treatment if necessary. Can also be used as a conductive layer. In this way, when the amorphous layer itself is a conductive layer, a transparent conductive laminate can be obtained without performing the heat treatment described below.

The conductive layer 4 obtained by crystallizing the amorphous layer is formed by heat-treating such an amorphous layer and crystallizing it into a crystalline transparent conductive film. The heat treatment is preferably performed, for example, in the atmosphere at 100 to 150 ° C. for 10 to 180 minutes. By setting the heat treatment temperature to 100 ° C. or more and the heat treatment time to 10 minutes or more, the amorphous layer can be effectively crystallized. Further, when the heat treatment temperature is 150 ° C. or less and the heat treatment time is 180 minutes or less, sufficient crystallization can be achieved. Note that the crystallized indium tin oxide has a crystal structure of indium oxide (In ₂ O ₃ ), and it is preferable that tin is substituted at the site of indium.

Thus, the transparent conductive laminate 10 in which the SiO _x1 layer 2, the SiO _x2 layer 3, and the conductive layer 4 are laminated in this order on one main surface of the transparent substrate 1 shown in FIG. 1, or 2 has

resin layers

5a and 5b on both main surfaces of the transparent substrate 1, and the SiO _x1 layer 2, the SiO _x2 layer 3, and the conductive layer 4 are laminated in this order on the resin layer 5a. A transparent conductive laminate 10 is obtained.

The transparent conductive laminate 10 shown in FIGS. 1 and 2 has been described above, but the transparent conductive laminate of the present invention is not limited to this. The transparent conductive laminate 10 can be changed or modified without departing from the spirit and scope of the present invention. The transparent conductive laminate of the present invention is suitably used for electronic equipment. Examples of the electronic device include a liquid crystal display, a plasma display, and a touch panel, and a touch panel is particularly preferable.

[Touch panel]
The touch panel of the present invention includes the transparent conductive laminate of the present invention. A touch panel has a display part and the touch panel part arrange | positioned in the front surface of this display part, for example. The transparent conductive laminate is used as a transparent electrode substrate having a transparent electrode in such a touch panel unit. The touch panel unit may be either a resistive film type that specifies a touch position by contacting upper and lower electrodes, or a capacitive coupling type that senses a change in capacitance.

Hereinafter, embodiments of the present invention will be specifically described with reference to examples. In addition, this invention is not limited by these Examples. In addition, Example 1 is an example, and Examples 2 and 3 are comparative examples. The thickness is a value obtained from optical characteristics or a sputtering film formation rate and a sputtering time, and is not an actually measured thickness. The thickness is a geometric thickness.

(Example 1)
A polyethylene terephthalate (PET) film having a total thickness of 100 μm having a hard coat layer (acrylic resin layer, 8 μm) on both surfaces was used as a transparent substrate with a hard coat layer. A 7 nm thick SiO _x1 layer (x1 = 1.95) was formed on the hardcoat layer of the transparent substrate with the hardcoat layer. The SiO _x1 layer was formed by performing AC magnetron sputtering at a pressure of 0.2 Pa while introducing a mixed gas obtained by mixing oxygen gas into argon gas using a boron-doped polysilicon target. The thickness of the SiO _x1 layer was adjusted by adjusting the power density and the sputtering time, and x1 was adjusted by adjusting the voltage and the oxygen flow rate.

A SiO _x2 layer (x2 = 2.0) having a thickness of 3 nm was formed on the SiO _x1 layer. The SiO _x2 layer was formed by performing AC magnetron sputtering at a pressure of 0.2 Pa while introducing a mixed gas obtained by mixing oxygen gas into argon gas using a boron-doped polysilicon target. The thickness of the SiO _x2 layer was adjusted by adjusting the power density and the sputtering time, and x2 was adjusted by adjusting the voltage and the oxygen flow rate.

The _{SiO x1} layer, on the _{SiO x2} layer of PET _{film SiO x2} layer is formed, using a target made of indium tin oxide, while introducing a mixed gas obtained by mixing 1.4% by volume of oxygen gas to argon gas However, DC magnetron sputtering was performed at a pressure of 0.25 Pa to form an amorphous layer having a thickness of 23 nm. The indium tin oxide target is composed of a sintered body obtained by mixing and sintering 10% by mass of tin oxide (SnO ₂ ) and 90% by mass of indium oxide (In ₂ O ₃ ). The thickness of the amorphous layer was adjusted by adjusting the power density and the sputtering time. The content of tin in terms of oxide in the amorphous layer is estimated to be about 10% by mass.

The obtained laminate was cut into a size of 100 mm × 100 mm, and the sheet resistance value was measured by the method described later. Although the obtained laminated body can be used as a transparent conductive laminated body as it is, in this example, this laminated body was heat-treated in the atmosphere at 150 ° C. for 30 minutes to produce a transparent conductive laminated body.

(Example 2)
On the same transparent substrate as in Example 1, a 10 nm thick SiO _x1 layer (x1 = 1.95) was formed. The SiO _x1 layer was formed by performing AC magnetron sputtering at a pressure of 0.2 Pa while introducing a mixed gas obtained by mixing oxygen gas into argon gas using a boron-doped polysilicon target. The thickness of the SiO _x1 layer was adjusted by adjusting the power density and the sputtering time, and x1 was adjusted by adjusting the voltage and the oxygen flow rate. A conductive layer mainly composed of indium tin oxide was formed on the SiO _x1 layer directly in the same manner as in Example 1 without forming the SiO _x2 layer.

In the formation of the conductive layer, the amorphous layer mainly composed of indium tin oxide was cut into a size of 100 mm × 100 mm before the heat treatment and the sheet resistance value was measured in the same manner as in Example 1, and then the heat treatment was performed. A transparent conductive laminate was produced.

(Example 3)
A SiO _x2 layer (x2 = 2.0) having a thickness of 10 nm was directly formed on the transparent substrate similar to Example 1 without forming the SiO _x1 layer. The SiO _x2 layer was formed by performing AC magnetron sputtering at a pressure of 0.2 Pa while introducing a mixed gas obtained by mixing oxygen gas into argon gas using a boron-doped polysilicon target. The thickness of the SiO _x2 layer was adjusted by adjusting the power density and the sputtering time, and x2 was adjusted by adjusting the discharge voltage and the oxygen flow rate. A conductive layer mainly composed of indium tin oxide was formed on the SiO _x2 layer in the same manner as in Example 1.

The following evaluation was performed about the transparent conductive laminated body obtained by said each example. The results are shown in Table 1.
(B * value)
Based on JIS Z8729 (2004), a transmittance spectrum (380 to 780 nm) of light incident from the conductive layer side of the transparent conductive laminate by a C light source is measured with a spectrophotometer (TC-1800 MKIII, manufactured by Tokyo Denshoku Co., Ltd.). ) To calculate L * a * b * values. The b * values are shown in Table 1.

(Sheet resistance value)
The sheet resistance value of each transparent conductive laminate having a size of 100 mm × 100 mm was measured by a four probe method using Lorester (trade name, manufactured by Mitsubishi Chemical Corporation).

(Alkali resistance)
After each transparent conductive laminate was immersed in a 5.6 mass% potassium hydroxide aqueous solution (40 ° C.) for 3 minutes, the presence or absence of cracks on the conductive layer side surface of the transparent conductive laminate was visually confirmed. Judgment was made according to the criteria.
○: No cracks are confirmed.
X: Even a slight crack is confirmed.

(Water vapor barrier property)
The water vapor permeability of each transparent conductive laminate was measured according to JIS K7129 B method (infrared sensor method) using a water vapor permeability measuring device (manufactured by MOCON, product name “PERMATRAN-W 3 / 33MG”). The measurement was performed in an atmosphere of 40 ° C. and humidity 90% RH. In addition, humidity control to the transparent conductive laminated body was made into the direction which water vapor | steam permeate | transmits from the film-forming surface side to the base material side. If the water vapor permeability is 0.5 g / m ² / day or less, it can be said that the water vapor barrier property is good.

* In Table 1, the HC layer represents a hard coat layer.

From Table 1, it turns out that the transparent conductive laminated body of Example 1 is a favorable result about all of color, resistance value, alkali resistance, and water vapor | steam barrier property. As for the water vapor barrier property, the transparent conductive laminate (Example 1) having the laminated structure of the SiO _x1 layer and the SiO _x2 layer has the best result even when the total thickness of the silicon oxide layer is 10 nm. Met. As shown in Example 3, the silicon oxide layer is essentially a complete oxide (SiO ₂ ), which has better barrier properties. However, when both barrier properties and adhesion to the substrate are compatible, SiOx (x <2) results better. Therefore, it is considered that the laminate of the SiO _x1 layer and the SiO _x2 layer has the highest adhesion and excellent barrier properties.

DESCRIPTION

_{OF SYMBOLS} 10 ... Transparent conductive laminated body, 1 ... Transparent base material, 2 ... _SiOx1 layer, 3 ... _SiOx2 layer, 4 ... Conductive layer, 5a, 5b ... Resin layer.

Claims

A transparent substrate;
A SiO x1 layer (provided that x1 is 1.8 or more and less than 2.0) having a thickness of 3 to 60 nm provided on one main surface of the transparent substrate;
SiO x2 layer thickness provided in the SiO x1 layer on the 0.2 ~ 5 nm (although, x2 is 1.9 or more and 2.0 or less, and x1 is greater than.) And,
A conductive layer mainly composed of indium tin oxide provided on the SiO x2 layer;
A transparent conductive laminate comprising:
The transparent conductive laminate according to claim 1, wherein the thickness of the SiO x1 layer is 3 to 10 nm.
The transparent conductive laminate according to claim 1 or 2, wherein the total thickness of the SiO x1 layer and the SiO x2 layer is 10 nm or less.
The transparent conductive laminate according to any one of claims 1 to 3, further comprising a resin layer between the transparent substrate and the SiO x1 layer.
A touch panel comprising the transparent conductive laminate according to any one of claims 1 to 4.