JP2009224152A - Transparent electrode, transparent conductive substrate, and transparent touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a transparent electrode with extremely thin film-thickness and superior thermal resistance; a transparent conductive substrate; and a transparent touch panel. <P>SOLUTION: In the transparent electrode of a lamination structure, a crystalline transparent conductive film (A) having indium oxide as a main component and an amorphous transparent conductive film (B) having indium oxide as a main component are formed in order on a substrate by a sputtering method; and the crystalline transparent conductive film (A) has a film-thickness of 5-40 nm, the amorphous transparent conductive film (B) has the film-thickness of 2-10 nm, and the surface resistance is 70-3,000 Ω/square. The transparent conductive substrate has the transparent electrode formed on the surface of a transparent substrate, and the transparent touch panel is obtained using the transparent conductive substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transparent electrode, a transparent conductive substrate, and a transparent touch panel, and more particularly to a transparent electrode, a transparent conductive substrate, and a transparent touch panel that are extremely thin and have excellent heat resistance.

  In recent years, in personal computers, word processors, electronic notebooks, portable terminals, etc., as an input device for inputting data to the computer main body (main storage device), a load is simply applied to the input surface with a finger or a pen. Transparent touch panels (including touch screens) that can perform data input have been widely used. There are various types of touch panels such as a resistance film type and a capacitance type. Resistive touch panels are roughly classified into an analog type and a digital type. Recently, an analog type transparent touch panel is being adopted in accordance with a demand for improving detection sensitivity of an input position.

  Transparent conductive films used as electrodes for transparent touch panels are generally ATO (antimony-containing tin oxide), FTO (fluorine-containing tin oxide), ITO (tin-containing indium oxide), ITiO (titanium-containing indium oxide), FATO (fluorine and Metal oxides such as antimony-containing tin oxide) are used. In particular, in the case of a resistance film type analog type transparent touch panel, a surface resistance value is 200 to 3000 Ω / □ (read as ohm-per-square), and a transparent electrode with high transparency and little color is used as an electrode. It has been demanded. When the touch panel is configured such that the surface resistance is less than 200Ω / □ and the two transparent substrates are arranged so that the transparent conductive film side faces each other, the opposing transparent conductive film comes into contact (when ON). The flowing current increases and the current consumption increases. On the other hand, when the surface resistance of the transparent conductive film exceeds 3000 Ω / □, electrical conduction at the time of contact becomes unstable. In the case of a capacitive touch panel, a transparent conductive film having a high transparency of 70 to 200Ω / □ is required as an electrode.

As an example, a resistive film type analog type transparent touch panel has a lower electrode substrate constituted by an insulating substrate such as a glass plate or a film provided with a lower electrode constituted by a transparent conductive film and a dot-like spacer on the surface, It has a structure in which an upper electrode substrate composed of an insulating substrate such as a film provided with an upper electrode composed of a transparent conductive film is laminated on the surface, and a part of the surface of the transparent touch panel is pressed from the input surface side. Thus, both electrodes can be brought into contact with each other to be electrically conducted for input.
This transparent conductive film is usually formed by a physical film formation method such as vapor deposition or sputtering, or a chemical vapor phase method such as CVD. In these methods, it is possible to control the average crystal grain size in the plane observed on the surface of the transparent conductive film. For example, in the case of a physical film forming method, a transparent conductive film generally composed of ITO or ITiO is generally used, and the surface resistance value is 200 to 3000Ω / □ in the case of a resistive film type touch panel. Slightly higher than the electrode for use is required. However, since ITO and ITiO have a small specific resistance, it is necessary to increase the surface resistance value by forming the film with a very thin film having a thickness of about 7 to 50 nm.
In general, a resistive touch panel has a structure in which an upper electrode made of a transparent substrate on which a thin film of a transparent conductive film is formed and a lower electrode in which a transparent conductor is provided on a glass or resin substrate are arranged at intervals. Have. In this resistive touch panel, when the input is made, the transparent conductive film peels off from the substrate because the surface is rubbed with a pen or the like while the transparent conductive film of the upper electrode and the transparent conductive film of the lower electrode are in contact with each other. Sometimes. In the portion where the transparent conductive film has been removed, the resistance value between the upper and lower electrodes becomes large, resulting in hindrance to input. In general, a transparent conductive film is more difficult to peel from a substrate than a crystal film, and is excellent in durability.

The transparent electrode for a transparent touch panel has a transparent substrate and a transparent conductive film formed on the one surface.
For example, in order to form a transparent conductive film such as an ITO or ITiO film by a sputtering method, first, in a cleaning process, a transparent substrate is cleaned with water (pure water) or alkaline water, and at a temperature of 120 ° C. or higher in the atmosphere. Dry for 1-4 hours. Then, sputtering film formation of ITO or ITiO is performed at a temperature of 200 to 400 ° C. under vacuum. By performing such high-temperature film formation, a crystalline transparent conductive film having strong adhesion to the substrate and excellent durability can be obtained. Thereafter, a silver paste is applied to the connection portion between the electrode and the lead electrode, and cured at a temperature of 130 to 170 ° C. At this time, if the heat resistance of the formed transparent electrode is not sufficient, the change in the surface resistance value is large, and if the change in the surface resistance of the transparent electrode is large in a temperature environment of 150 to 200 ° C., the high heat resistance is high. It cannot be used as an electrode for the required on-vehicle car navigation touch panel.

Numerous studies have been conducted so far to improve heat resistance. As for improving the heat resistance of the transparent conductive film itself, in Patent Document 1, the Ga concentration in the ZnO transparent conductive film is controlled to 0.5 to 12% in terms of Ga / Zn atomic ratio, and (002) It has been proposed to control the crystallinity of the film so that the half width of the X-ray diffraction line is 0.6 degrees or less. As a result, the specific resistance value is as low as 2 × 10 ⁻⁴ Ω · cm, which is equivalent to that of ITO. Furthermore, there is no deterioration in conductivity after heat treatment in air at 500 ° C. or higher, and extremely high heat resistance in an oxidizing atmosphere It is described that an excellent film can be obtained.

  Patent Document 2 discloses a sputtering target represented by In 2 O 3 that contains indium, tin, zinc, and oxygen, and in which only the peak of the bixbite structure compound is substantially observed by X-ray diffraction (XRD). A transparent conductive film formed by using the film has been proposed. Here, even if the indium content is reduced within the range of 60 to 75 atomic%, the etching processability similar to that of IZO and the film performance equivalent to that of ITO are exhibited. Excellent in heat resistance, heat resistance, etc., suitable for various applications such as liquid crystal displays, touch panels, solar cells, etc. It is described that it can also be applied to film formation.

  Furthermore, an attempt to improve heat resistance using a transparent conductive film as a laminated film has also been proposed. Patent Document 3 discloses a protective film that does not deteriorate the electrical and optical characteristics of a conductive film while having sufficient corrosion resistance on a conventional transparent conductive film mainly composed of a metal oxide such as indium oxide or tin oxide. A transparent conductive film is disclosed in which a protective film mainly composed of zinc oxide containing gallium is formed.

  In addition, when an ITO film is formed using a polyarylate molded article as a base material to form a transparent conductive laminate, the electrical resistance value may change due to heat treatment and wet heat treatment. A layer mainly composed of amorphous indium oxide having a high barrier property is formed on at least one surface of a simple substrate as an intermediate layer by sputtering in a high-concentration oxygen atmosphere, and an oxide mainly composed of indium and tin is formed on the intermediate layer. It has been proposed to form a transparent conductive layer composed of a product, and it is disclosed that a transparent conductive laminate having excellent heat resistance and moist heat resistance can be obtained even when polyarylate or the like is used as a transparent substrate. Yes.

Thus, although the transparent conductive film and transparent conductive laminated body which are excellent in heat resistance, heat-and-moisture resistance, etc. are proposed, when any transparent conductive film becomes a film thickness of about 7-50 nm, it is the atmosphere in 150-200 degreeC. Heat resistance deterioration in the inside becomes remarkable. This is presumably because, since the film thickness is 50 nm or less, the electrical characteristics are likely to deteriorate due to the oxidation of the film surface and the diffusion of oxygen from the film surface under the above environment. A transparent electrode having a stable surface resistance value for a heating process in a touch panel manufacturing process and a demand for a high heat-resistant temperature for car navigation applications has not been obtained so far.
JP-A-7-249316 JP 2007-84842 A JP-A-6-338223 Japanese Patent Laid-Open No. 9-226046

  In view of the above problems, an object of the present invention is to provide a transparent electrode, a transparent conductive substrate, and a transparent touch panel that are excellent in heat resistance in the air at 150 ° C. or higher even with an extremely thin film having a film thickness of 50 nm or less. There is.

  As a result of intensive studies in solving the above problems, the present inventors have found that a crystalline transparent conductive film mainly composed of indium oxide and an amorphous transparent conductive film mainly composed of indium oxide on the substrate. Heat resistance as a transparent conductive film was improved without impairing optical properties by forming a transparent electrode having a laminated structure in which films were sequentially formed with specific film thicknesses, and further, a transparent conductive film was produced at a high temperature. Even in this case, it was found that the characteristics of the laminated film are hardly affected, and the present invention has been completed.

  That is, according to the first invention of the present invention, on the substrate (C), the crystalline transparent conductive film (A) mainly composed of indium oxide and the amorphous transparent conductive film mainly composed of indium oxide. (B) is a transparent electrode having a laminated structure in which the crystalline transparent conductive film (A) has a film thickness of 5 to 40 nm, and the amorphous transparent conductive film (B) has a film thickness of 2 to 2. A transparent electrode having a thickness of 10 nm and a surface resistance of 70 to 3000 Ω / □ is provided.

According to the second invention of the present invention, in the first invention, the crystalline transparent conductive film (A) is an indium oxide containing at least one additive element (Me) selected from tin or titanium. The transparent electrode is characterized in that the total content is 0.01 to 0.15 in terms of Me / In atomic ratio.
According to the third invention of the present invention, in the first invention, the amorphous transparent conductive film (B) is added with at least one selected from gallium, cerium, silicon, germanium, tungsten, or zinc. A transparent electrode is provided, which is indium oxide containing an element (Me) and has a total content of 0.04 to 0.80 in terms of Me ₂ / In atomic ratio.
According to a fourth aspect of the present invention, there is provided the transparent electrode according to the third aspect, wherein the crystallization temperature of the amorphous transparent conductive film (B) is 250 ° C. or higher. .
According to a fifth aspect of the present invention, in the first aspect, the substrate (C) is any transparent substrate selected from a glass plate, a plastic resin plate, or a resin film. A transparent electrode is provided.
According to the sixth invention of the present invention, in any one of the first to fifth inventions, the crystalline transparent conductive film (A) on the substrate (C) heated to 200 ° C. or higher by the sputtering method. And an amorphous transparent conductive film (B) are sequentially formed to provide a transparent electrode.
According to the seventh invention of the present invention, in the first invention, the rate of change in surface resistance (R / R ₀ , where R: heat resistance test for 1 hour at a temperature of 150 ° C. or higher in the atmosphere. A transparent electrode is provided in which the subsequent surface resistance, R ₀ : surface resistance before test) is 0.80 to 1.20.
Furthermore, according to the eighth invention of the present invention, there is provided the transparent electrode according to the seventh invention, wherein the transparent electrode is heated to 200 ° C. in the heat resistance test.

On the other hand, according to the ninth invention of the present invention, there is provided a transparent conductive substrate according to any one of the first to eighth inventions, wherein the transparent electrode is formed on the surface of the transparent substrate.
According to a tenth aspect of the present invention, in the ninth aspect, there is provided a transparent touch panel using the transparent conductive substrate as a lower electrode and / or an upper electrode.
Furthermore, according to an eleventh aspect of the present invention, there is provided the transparent touch panel according to the tenth aspect, wherein the lower electrode and the upper electrode are laminated facing each other with a spacer interposed therebetween.

The transparent electrode of the present invention is excellent in heat resistance in the air at 150 ° C. or higher, despite being an extremely thin film having a thickness of 50 nm or less. That is, when the electrode and the lead electrode are applied with silver paste and cured at a temperature of 130 to 170 ° C., the change in the surface resistance value of the formed transparent electrode is extremely small. Moreover, since the transparent electrode of the present invention is excellent in heat resistance in the atmosphere at 200 ° C., it is suitable as an electrode for an in-vehicle car navigation touch panel.
Therefore, the transparent touch panel using the transparent electrode of the present invention has excellent heat resistance, and is used for a display screen of a flat display such as a liquid crystal display device, an electroluminescence element, a plasma display element, a fluorescent display tube, and a field emission display. It can be suitably used as an input device by being laminated, and is extremely useful industrially.

  Next, features of the present invention will be described in detail with reference to the drawings.

1. Transparent electrode The transparent electrode of the present invention comprises a crystalline transparent conductive film (A) mainly composed of indium oxide and an amorphous transparent conductive film (B) mainly composed of indium oxide on a substrate (C). A transparent electrode having a laminated structure formed in sequence, the crystalline transparent conductive film (A) has a thickness of 5 to 40 nm, the amorphous transparent conductive film (B) has a thickness of 2 to 10 nm, The surface resistance is 70 to 3000 Ω / □.

(1) Structure of transparent electrode The structure of the transparent electrode of this invention is shown in FIG. The transparent electrode (4) of the present invention comprises a crystalline transparent conductive film (1) mainly composed of indium oxide and an amorphous transparent conductive film (2) mainly composed of indium oxide on a substrate (3). It is formed sequentially and has a laminated structure.

  FIG. 3 shows a cross-sectional TEM image of the transparent electrode of the present invention. In FIG. 3, a crystalline transparent conductive film (In—Ti—Sn—O film) 1 confirmed at a crystal grain boundary 7 is formed on a glass substrate 3. On the film 1, a film 2 having a thickness of 4 nm is formed. This film is an amorphous transparent conductive film (In—Ga—O film) 2 because there is no crystal grain boundary and the atomic arrangement is not regular. When electron beam diffraction measurement is performed in a local region by focusing an electron beam on the 1 nm region, a diffraction spot peculiar to a crystalline film is observed in the film 1, and a halo pattern peculiar to an amorphous film is observed in the film 2. Observed.

  The transparent electrode of the present invention must have a structure in which an amorphous transparent conductive film (2) is laminated on the surface of a crystalline transparent conductive film (1). The amorphous transparent conductive film (2) not only transmits the conductivity of the crystalline transparent conductive film (1) to the surface, but also has a gas barrier function for preventing oxygen from entering the atmosphere. Unlike a crystal film, an amorphous film has very little gas ingress because there is no grain boundary. Thereby, even in a high temperature environment of 150 to 200 ° C. in the atmosphere, the oxidation of the crystalline transparent conductive film can be prevented and the heat resistance can be dramatically improved.

  The transparent electrode of the present invention needs to have a surface resistance of 70 to 3000 Ω / □. If it deviates from this range, it cannot be used as a capacitive touch panel or a resistive touch panel.

(2) Crystalline transparent conductive film (A)
More preferably, the crystalline transparent conductive film in the transparent electrode of the present invention contains indium oxide as a main component and contains at least one selected from tin and titanium.

An indium oxide film containing at least one selected from tin and titanium has excellent crystallinity, and realizes a surface resistance value (70 to 3000 Ω / □) suitable as a touch panel even with an extremely thin film thickness of 5 to 40 nm. be able to. The total amount of at least one additive element (Me) selected from tin and titanium is preferably 0.01 to 0.15 in terms of the Me / In atomic ratio.
Of course, the same effect can be obtained by including both tin and titanium at the same time. However, the indium oxide thin film containing titanium and containing as little tin as possible has excellent crystallinity, strong adhesion to the substrate, and excellent durability. It is preferable because an electrode can be formed and an electrode with large surface irregularities is easily formed, leading to an improvement in the response speed of the touch panel. Further, in addition to tin and titanium, other elements (for example, zinc, magnesium, gallium, germanium, silicon, tungsten, molybdenum, cerium, etc.) may be contained in a trace amount to such an extent that the characteristics of the present invention are not impaired. It doesn't matter.

  The film thickness of the crystalline transparent conductive film is 5 to 40 nm. When the thickness is less than 5 nm, it is not preferable because the film becomes an island shape and does not exhibit a stable surface resistance particularly when formed on a substrate having a composition different from that of glass or the like. This is because the film including the amorphous transparent conductive film covering the surface becomes too thick and the transmittance decreases. In order to achieve an excellent light transmittance of 91% or more with a transparent electrode alone in the visible region, the total film thickness of the laminate of the crystalline transparent conductive film and the amorphous transparent conductive film is 50 nm or less. There must be.

(3) Amorphous transparent conductive film (B)
The amorphous transparent conductive film in the transparent electrode of the present invention is more preferably one containing indium oxide as a main component and containing at least one selected from gallium, cerium, silicon, germanium, tungsten and zinc.

When at least one selected from gallium, cerium, silicon, germanium, tungsten, and zinc is added to indium oxide, the crystallization temperature is remarkably increased, and crystallization does not occur even in a high temperature environment of 150 to 200 ° C., and the substrate temperature However, it is advantageous because an amorphous film can be stably obtained even by sputtering film formation at 200 to 230 ° C.
The total amount of at least one additive element (Me) selected from gallium, cerium, silicon, germanium, tungsten, and zinc is preferably 0.04 to 0.80 in terms of the Me / In atomic ratio. If it is less than 0.04, the crystallization temperature is too low and amorphousness cannot be stably obtained, and if it exceeds 0.80, the electrical properties of the amorphous film become close to insulating properties, It is not preferable because the conductivity of the conductive transparent conductive film cannot be transmitted to the surface.
Among these, indium oxide containing gallium is most preferable because it is particularly excellent in heat resistance and gas barrier properties. In addition to gallium, cerium, silicon, germanium, and / or tungsten, other elements (eg, magnesium, calcium, tin, titanium, molybdenum, etc.) are contained in a trace amount to such an extent that the characteristics of the present invention are not impaired. It doesn't matter.

In order to obtain desired characteristics even under the above film forming conditions, the crystallization temperature of the amorphous transparent conductive film (2) needs to be 250 ° C. or higher. More preferably, it is 350 degreeC or more. This is not only necessary for the heat resistance of 200 ° C. required for touch panels for car navigation systems, etc., because the amorphous transparent conductive film on the surface does not crystallize, but also a crystal with high adhesion on the substrate. In order to form a conductive transparent conductive film and an amorphous transparent conductive film, it is very effective to continuously form a transparent conductive film by sputtering on a substrate heated to 200 to 230 ° C., After forming the crystalline transparent conductive film at the substrate temperature, the amorphous transparent conductive film having the crystallization temperature is used to form a desired amorphous transparent conductive film without taking much time. This is because the film needs to be a film, and in that case, it can be used in the manufacturing process as described above and can be stably maintained as an amorphous film.
In general, thin films such as SiO ₂ , SiOx, SiON, and SiNx are known as amorphous films that exhibit a gas barrier function. However, since these are insulative, if they are covered on the surface of a transparent conductive film, they are electrically conductive. Sex cannot be transmitted to the surface. In the present invention, it has not only gas barrier properties but also conductivity, and is an amorphous transparent conductive film having a stable structure and maintaining conductivity even at 250 ° C. or higher, more preferably 350 ° C. or higher. A major feature is to cover the surface of the conductive film.

  The film thickness of the amorphous transparent conductive film is 2 to 10 nm. It is because it is inferior to gas barrier property as it is less than 2 nm, and the heat resistance of the transparent electrode obtained will worsen. Moreover, when the film thickness of the amorphous transparent conductive film is 2 nm or more, gas barrier properties are exhibited. However, when the film thickness exceeds 10 nm, the total film thickness of the transparent electrode becomes too thick and the transmittance decreases, and the material cost also increases. Is also undesirable because it increases. Therefore, the film thickness of the amorphous transparent conductive film is preferably 2 to 10 nm.

(4) Substrate (C)
The substrate may be a glass plate, a plastic resin plate, or a resin film. In addition, a thin film such as silicon oxide having excellent barrier properties against the leaching of metal ions and gas from the film and the entering of the film may be formed on the surface of the glass plate, the plastic resin plate or the resin film. .

(5) Film formation method The transparent electrode of the present invention is preferably produced by sequentially forming a crystalline transparent conductive film and an amorphous transparent conductive film by a sputtering method at a substrate temperature of 200 ° C. or higher. .

In the sputtering method, generally, under an argon gas pressure of about 10 Pa or less, a substrate is used as an anode and a target is used as a cathode, and glow discharge is generated between them to generate argon plasma. Argon cations in the plasma collide with a cathode target to blow off target component particles, and deposit the particles on a substrate to form a film.
Sputtering methods are classified according to the method of generating argon plasma. Those using high-frequency plasma are called high-frequency sputtering methods, and those using DC plasma are called DC sputtering methods. In addition, a magnetron sputtering method is a method in which a magnet is disposed on the back side of a target so that argon plasma is concentrated directly on the target to increase the collision efficiency of argon ions so that a film can be formed even at a low gas pressure.

In the transparent electrode of the present invention, a crystalline transparent conductive film and an amorphous transparent conductive film are sequentially formed by sputtering at a substrate temperature of 200 ° C. or higher, preferably 200 to 350 ° C. .
The reason why the crystalline transparent conductive film (1) is formed on a substrate such as a glass plate is to enhance the adhesion between the substrate and the film. In general, glass, a plastic resin plate, a resin film, or the like is generally used for the substrate. However, since the composition and crystal structure are different from those of the transparent conductive film, the chemical bond is poor and it is difficult to obtain a strong adhesive force. In particular, when it is formed on a resin, it is difficult to obtain a strong adhesive force. However, a strong adhesion can be obtained by sputtering a crystalline transparent conductive film at a high temperature of 200 ° C. or higher. On the other hand, when an amorphous transparent conductive film or a film in which crystals and amorphous are mixed is formed, the film is easily peeled off from the substrate, resulting in poor durability.
Therefore, if there is only a crystalline transparent conductive film in a high temperature environment of 150 to 200 ° C. in the atmosphere, the film absorbs oxygen in the atmosphere and oxidizes, resulting in a significant change in conductivity. In particular, in the case of a thin film having a thickness of 5 to 40 nm, it is easy to diffuse and enter oxygen into the film, and the change in conductivity is remarkable.

  When the substrate temperature is less than 200 ° C., the adhesive force between the crystalline transparent conductive film and the substrate is weak, and the durability when used by rubbing with a pen or the like is poor. Further, when the temperature exceeds 500 ° C., not only a resin plate or film having a low softening point cannot be used, but a cooling time is required, which takes time and causes problems such as manufacturing costs. Since the transparent electrode obtained by such a manufacturing method has a high adhesion to the substrate, it has excellent durability when rubbed with a pen or the like.

The substrate temperature is important for the film formation conditions, and the target type (additive element content) is selected appropriately in consideration of the crystallinity of the resulting film, and the oxygen content, pressure, inert gas, input power It is done by adjusting the amount.
As a target, a powder sintering method, that is, a method in which an oxide of a metal element that is substantially an additive element is added to indium oxide in a desired composition, pressure-molded, and then sintered at a temperature of 1400 ° C. or higher. The indium oxide-based sintered body produced by the above is used. The indium oxide-based sintered body is processed by surface grinding or the like to have a predetermined dimension, and is then attached to a backing plate.
The amount of the additive element of the target may be considered that composition deviation hardly occurs at the time of film formation, and the same amount as the film composition is selected. In the present invention, it is preferable that the crystalline transparent conductive film on the substrate does not contain an element that hinders crystallinity, so that the target does not contain gallium, cerium, silicon, germanium, tungsten, or zinc. It is desirable to use it. In the case where at least one additive element (Me) selected from gallium, cerium, silicon, germanium, tungsten, and zinc is included, a target whose total amount is less than 0.02 in terms of Me / In atomic ratio is used. In order to obtain a crystal film with a high temperature substrate of 200 ° C. or higher, it is necessary.
The oxygen amount, pressure, and input electric power amount also depend on the film forming apparatus and cannot be generally specified, but the gas pressure is 0.1 to 2.0 Pa, the gas type is a mixed gas of argon and oxygen, and the oxygen mixture amount is 0. .5 to 10% input power amount: 0.8 to 3.5 W / cm ²
Under such conditions, the film is formed until the crystalline transparent conductive film has a thickness of 5 to 40 nm. When the thickness is less than 5 nm, it is not preferable because the film becomes an island shape and does not exhibit a stable surface resistance particularly when formed on a substrate having a composition different from that of glass or the like. The film including the amorphous transparent conductive film covering the surface becomes too thick, and the transmittance decreases. In order to achieve an excellent light transmittance of 91% or more with a transparent electrode alone in the visible region, the total film thickness of the laminate of the crystalline transparent conductive film and the amorphous transparent conductive film is 50 nm or less. There must be.

Thereafter, an amorphous transparent conductive film is formed by changing the target. Since it is preferable that the amorphous transparent conductive film contains an element that hinders crystallinity, it is preferable to use a target containing gallium, cerium, silicon, germanium, tungsten, or zinc. The total amount of at least one additive element (Me) selected from gallium, cerium, silicon, germanium, tungsten, and zinc is 200 ° C. or higher by using a target having a Me / In atomic ratio of 0.04 or more. It is necessary to obtain an amorphous film with a high temperature substrate. However, when a target having a total amount of additive element (Me) exceeding 0.80 in the Me / In atomic ratio is used, the electrical characteristics of the amorphous film having almost the same composition as the target become close to insulating, and the crystal It is not preferable because the conductivity of the conductive transparent conductive film cannot be transmitted to the surface.
The substrate temperature, oxygen amount, pressure, and input power amount may be changed within the above ranges, but the present invention may be the same as the conditions for forming the crystalline transparent conductive film. For this reason, operation is easier than before, productivity can be increased, and the cost of the transparent electrode can be reduced.

The transparent electrode of the present invention thus obtained has a surface resistance R ₀ before the test (room temperature) and a surface resistance R after the test in a heat resistance test that is heated in the atmosphere at a temperature of 150 ° C. or higher for 1 hour. The change (R / R ₀ ) is 0.80 to 1.20. Because of having such excellent heat resistance, when the silver paste is applied to the connection portion of the electrode and the lead electrode and cured at a temperature of 150 ° C., the change in the surface resistance value of the transparent electrode is extremely small, A touch panel with stable quality can be manufactured. In the heat resistance test in which the transparent electrode of the present invention is heated in the atmosphere at 200 ° C. for 1 hour, when the surface resistance R ₀ before the test and the surface resistance R after the test are taken, the change (R / R ₀ ) 0.80 to 1.20.
When a heat resistance test similar to the above was performed on a conventional transparent electrode and the change in surface resistance R (R / R ₀ ) was measured, most of them exceeded 1.20. Therefore, the transparent electrode of the present invention was excellent. Although it has heat resistance, it is also suitable for an electrode of a car navigation touch panel.

2. Transparent conductive substrate The transparent conductive substrate of the present invention is such that the transparent electrode is formed on the surface of the transparent substrate.

The transparent conductive substrate of the present invention has a transparent electrode having a laminated structure in which a crystalline transparent conductive film mainly composed of indium oxide and an amorphous transparent conductive film mainly composed of indium oxide are sequentially formed. It is a substrate. As described above, the crystalline transparent conductive film has a thickness of 5 to 40 nm, the amorphous transparent conductive film has a thickness of 2 to 10 nm, and the surface resistance is 70 to 3000 Ω / □.
The transparent substrate needs to be a material having excellent heat resistance that does not change even in the above manufacturing process, and glass, a heat resistant resin plate having a heat resistance of 200 ° C. or higher, and a heat resistant resin film are suitable. Specific examples include, but are not limited to, polyimide, aramid, polyphenylene sulfide, polyether sulfone, and the like. The resin plate or the resin film may have an inorganic film such as silicon oxide, silicon oxynitride, or silicon nitride formed inside or on the surface thereof. Although the thickness in particular is not restrict | limited, For glass and a heat resistant resin board, 0.3-3.2 mm is appropriate, and if it is a heat resistant resin film, 50 micrometers-3.2 mm are suitable.

3. Transparent touch panel The transparent touch panel of the present invention is obtained by using the transparent conductive substrate as a lower electrode and / or an upper electrode, and the lower electrode and the upper electrode are laminated with a spacer therebetween as shown in FIG. Structure. The substrate of the upper electrode or the lower electrode may be glass, a resin plate, or a resin film, but if it is a glass substrate, it has mechanical strength and can be used for many applications. In the transparent touch panel of the present invention, since the transparent electrode having excellent heat resistance is used for at least one of the electrodes, it can be suitably used for in-vehicle car navigation applications.

In the analog touch panel, as shown in FIG. 2, an upper electrode (6) made of a glass substrate (3-1) on which a transparent electrode (4-1) is formed is prepared, and the transparent electrode (4-1) On the formation surface, resist printing, etching, silver ink printing and insulating ink printing are performed to form parallel electrodes and routing circuits. Then, it prints with electroconductive heat seal ink, it bonds together using a double-sided tape, and it punches out to make an electrode. Moreover, the lower electrode 9 which provided the transparent conductive film (4-2) on the glass-made board | substrate (3-2) is prepared, and a parallel electrode and a lead circuit are similarly produced for this. Next, spacers (5, 9) are disposed so that the transparent electrode surfaces of the two faces each other, and the upper and lower electrodes are bonded to each other with a space therebetween. As the spacer, for example, spherical glass or hard resin having a diameter of about 3 to 10 μm is preferable. The amount used depends on the type of the spacer and the type of the touch panel, but it is preferably disposed at a density of 50 to 300 / mm ² , for example. Moreover, although the space | interval of an upper-and-lower electrode is based also on the type of a touch panel, it is preferable to leave 3-20 micrometers, for example. Finally, it is heat-sealed and electrically connected to form a touch panel.

The transparent touch panel of the present invention can be directly attached to the LCD, which reduces reflected light and makes the display easier to see. Moreover, in order to prevent the crack by fall, the transparent substrate which is a structural member can be made into glass with higher impact strength, or special resin can also be used. The transparent touch panel of the present invention may adopt any of these known configurations.
The transparent touch panel of the present invention is used by being mounted on a display body such as an LCD or an organic EL. When the input is performed with a pen, the force applied through the transparent touch panel may blur the display of the LCD or the like. Therefore, the transparent touch panel is preferably attached with a gap from the LCD.

  Hereinafter, more specific examples of the above-described embodiment will be given, and the excellent operational effects will be shown in comparison with comparative examples. The present invention is not limited to these examples. The properties and properties of the transparent electrode of the laminate were measured and evaluated as follows.

<Crystallinity of each layer of transparent electrode>
The crystallinity of the transparent electrode layer of the laminate was thinned by FIB processing and carried out by cross-sectional TEM observation and electron diffraction measurement. The film thickness of each layer was also measured from a cross-sectional TEM image. Cross-sectional TEM observation of the first layer and the second layer of the sample was performed, and the layer in which the crystal alignment was observed was determined to be crystalline, and the non-arranged layer was determined to be amorphous. Further, electron beam diffraction was performed on the first layer and the second layer, and the layer in which diffraction spots and diffraction rings were observed was judged to be crystalline, and the layer in which the halo pattern was observed was judged to be amorphous.

<Characteristic evaluation of transparent electrode film>
The surface resistance value was measured by a four-end needle method using a resistivity measuring device (Loresta-EP MCP-T360 manufactured by Mitsubishi Chemical Corporation).
Spectral transmission characteristics were measured with a spectrophotometer (manufactured by JASCO, V-570). The transmittance of only the substrate (T _S (%)) and the transmittance of the substrate to which the film is attached (T _{S + F} (%)) are measured every wavelength of 1 nm, and the transmittance of the film itself (T _F (%) = (T _{S + F} / T _S ) × 100) and the average transmittance in the visible region (wavelength 400 to 800 nm) was calculated.

<Composition analysis of each layer film>
Only a thin film of the first layer was formed to a thickness of 2 μm on a synthetic quartz substrate. The film formation conditions were the same as the film formation conditions for the crystalline transparent conductive film in the production of the transparent electrode. Using this film sample, the composition by ICP emission spectroscopic analysis was analyzed to obtain the composition of the thin film of the first layer in the transparent electrode. The composition of the second layer thin film was determined in the same procedure. Moreover, the X-ray diffraction measurement of this film | membrane was performed, and the crystallinity of each layer when producing the following laminated body was analyzed preliminary.

(Examples 1-14, Comparative Examples 1-6)
First, a thin film production target was produced in the following manner.
<First Layer Thin Film Target>
(1) In-Ti-O-based transparent conductive film production target A predetermined amount of indium oxide powder and titanium oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered to contain titanium. An indium oxide sintered body was prepared. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
(2) Target for preparing an In—Sn—O-based transparent conductive film A predetermined amount of indium oxide powder and tin oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered to contain tin. An indium oxide sintered body was prepared. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
(3) In-Ti-Sn-O-based transparent conductive film preparation target A predetermined amount of indium oxide powder, titanium oxide powder, and tin oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered. Thus, an indium oxide sintered body containing titanium and tin was produced. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
<Second-layer thin film target>
(4) In-Ga-O-based transparent conductive film production target A predetermined amount of indium oxide powder and gallium oxide powder are mixed in various proportions, and the mixture is molded, then heated and sintered to contain titanium. An indium oxide sintered body was prepared. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
(5) In-Sn-O-based transparent conductive film production target A predetermined amount of indium oxide powder and tin oxide powder are mixed in various proportions, and the mixture is molded, then heated and sintered to contain tin. An indium oxide sintered body was prepared. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target. This is the same as (2) above.
(6) In—Ga—Sn—O-based transparent conductive film production target A predetermined amount of indium oxide powder, gallium oxide and tin oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered. Thus, an indium oxide sintered body containing tin was produced. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.

<Preparation of transparent electrode>
Next, one target from (1) to (3) and one target from (4) to (6) were attached to the two nonmagnetic target cathodes of the DC magnetron sputtering apparatus. .
A glass substrate having a thickness of 1 mm was attached to the substrate holder. The substrate holder can be moved in the deposition vacuum chamber, and the substrate can be disposed on the opposing surface of each target. First, the substrate is stationaryly arranged on the facing portion of the first layer thin film production target to form the first layer thin film, and then the substrate is statically arranged on the facing portion of the second layer thin film production target. A second layer thin film was formed to produce a transparent electrode. The distance between each target and the substrate was 50 to 80 mm.
Thereafter, in Examples 1 to 10 and Comparative Examples 1 to 4, the glass substrate fixed to the substrate holder in the film formation vacuum chamber was heated to a temperature of 300 ° C., and the degree of vacuum in the film formation vacuum chamber was 1 × 10 ^{−. When the} pressure reaches ⁴ Pa or less, argon gas having a purity of 99.9999% by mass is introduced into the film-formation vacuum chamber so that the gas pressure is 0.3 to 0.8 Pa and oxygen gas is argon by 0.25 to 5%. Mixed into gas. A direct current power of 350 W was applied between the target and the substrate to generate direct current plasma, and sputtering film formation was performed. Each target was pre-sputtered for 20 minutes to clean the target surface, and then a first layer thin film and a second layer thin film having a predetermined thickness were sequentially formed.
On the other hand, in Examples 11-14 and Comparative Examples 5-6, it carried out similarly to the above except having heated the glass substrate fixed to the substrate holder in the film-forming vacuum chamber to the temperature of 200 degreeC.

<Heating test>
In Examples 1 to 10 and Comparative Examples 1 to 4, the produced transparent electrode was put in an atmospheric oven heated to 200 ° C., heated for 1 hour, then taken out of the oven and cooled to room temperature. The surface resistance value of the transparent electrode at room temperature (23 ° C.) before and after the heating test was measured by the four probe method.
Moreover, in Examples 11-14 and Comparative Examples 5-6, the produced transparent electrode was put into the atmospheric oven heated at 150 degreeC, and after heating for 1 hour, it took out from oven and cooled to room temperature (23 degreeC). The surface resistance value was measured.
Table 1 shows the configuration of the produced transparent electrode and the results of the heating test.

<Evaluation>
Examples 1 to 10 and Comparative Examples 1 to 4 in Table 1 are transparent electrodes formed at 300 ° C., and the heating test is the result of carrying out at 200 ° C. FIG. 3 shows a cross-sectional TEM image of the transparent electrode of Example 1. In FIG. 3, a crystalline transparent conductive film 1 (in this case, an In—Ti—Sn—O film) confirmed at a crystal grain boundary 7 is formed on a substrate 3 (in this case, a glass substrate). Was confirmed. On the film 1, a film 2 having a thickness of 4 nm is formed. However, since there is no crystal grain boundary and the atomic arrangement is not regular, the amorphous transparent conductive film 2 (in this case, In -Ga-O film). Further, when electron beam diffraction measurement is performed in a local region by narrowing the electron beam to the 1 nm region, it is confirmed that the film 1 is a crystal film because a diffraction spot is observed, and the film 2 has a halo pattern observed. As a result, it was confirmed to be an amorphous film. For each of the transparent electrodes other than Example 1 (including comparative examples), the crystallinity of each layer was evaluated from the same TEM and electron diffraction measurement, and the results are shown in Table 1. As is clear from Table 1, in the transparent electrodes of Comparative Examples 1 to 4, the second layer thin film was crystalline, but the change in the surface resistance value before and after the test heated at 200 ° C. for 1 hour in the atmosphere (R / R ₀ ) deviates from the range of 0.80 to 1.20, and such a transparent electrode cannot be used as an electrode for a touch panel such as an in-vehicle car navigation system that requires heat resistance.

On the other hand, in the transparent electrodes of Examples 1 to 10, the second layer thin film was an In—Ga—O-based or In—Ga—Sn—O-based transparent conductive film, and was not formed even though it was formed at 300 ° C. Since it is crystalline, it covers the surface of the transparent conductive film of the first layer thinly (2 to 10 nm in thickness), thereby exhibiting a barrier property against oxidation of the film of the first layer, and the surface resistance value before and after the heating test Change (R / R ₀ ) can be suppressed to an extremely small range of 0.80 to 1.20. Moreover, the average transmittance | permeability of the visible region of the transparent electrode itself before a heat test was 91% or more, and the transparency was also excellent. Therefore, such a transparent electrode can be effectively used as an electrode for a touch panel such as an in-vehicle car navigation system that requires heat resistance.

In addition, Examples 11 to 14 and Comparative Examples 5 to 6 in Table 1 are transparent electrodes formed at 200 ° C., and a heating test at 150 ° C. is performed. In the transparent electrodes of Examples 11 to 14, the change in surface resistance value (R / R ₀ ) was less than 1.05 in a heating test at 150 ° C. for 1 hour, and the change was extremely small. When the film is formed at 200 ° C., the composition range (Ga / In) for making the second layer thin film amorphous is wider than that at the time of film formation at 300 ° C. For example, in Comparative Example 1 of film formation at 300 ° C., the second layer having a composition of Ga / In = 0.080 was crystalline, but in Example 13 of film formation at 200 ° C., the same composition was used. It is amorphous and has a barrier effect. In general, when the amount of Ga in the film increases, the crystallization temperature increases, and it can be assumed that a film with Ga / In = 0.080 exists between 200 and 300 ° C. in the crystallization temperature.
In Comparative Examples 5 to 6, the change in surface resistance value (R / R ₀ ) before and after the heat test at 150 ° C. for 1 hour in the atmosphere deviates from the range of 0.80 to 1.20. In the transparent electrode as in Comparative Examples 5 to 6, in the heating process (150 ° C.) when the silver paste is applied to the connection portion of the electrode and the lead electrode and cured at the time of manufacturing the touch panel, the resistance value changes significantly. For this reason, it cannot be manufactured with uniform and stable characteristics.

(Examples 15-16, Comparative Examples 7-8)
A transparent electrode was prepared and evaluated in the same manner as in Examples 13 to 14 except that In—Ce—O and In—Ce—Sn—O were selected as the second layer thin film. The target was produced as follows. The substrate temperature during film formation by sputtering was 200 ° C.
(7) In-Ce-O-based transparent conductive film production target A predetermined amount of indium oxide powder and cerium oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered to contain cerium. An indium oxide sintered body was prepared. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
(8) In-Ce-Sn-O-based transparent conductive film preparation target A predetermined amount of indium oxide powder, cerium oxide powder, and tin oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered. Thus, an indium oxide sintered body containing cerium and tin was produced. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
The evaluation results are shown in Table 2.

In Comparative Examples 7 to 8, since the In-Ce-O (In-Ce-Sn-O) thin film of the second layer is a crystalline film, the surface resistance values before and after the test heated at 150 ° C. for 1 hour in the atmosphere Change (R / R ₀ ) deviated from the range of 0.80 to 1.20. In the transparent electrode as in Comparative Examples 7 to 8, the resistance value changes significantly in the heating step (150 ° C.) when the silver paste is applied to the connecting portion of the electrode and the lead electrode and cured when the touch panel is manufactured. For this reason, it cannot be manufactured with uniform and stable characteristics. In Examples 15 to 16, since the second-layer In—Ce—O (In—Ce—Sn—O) -based thin film is covered with an amorphous film, the change in resistance value is within that range. . Moreover, the average transmittance | permeability of the visible region of the transparent electrode itself before a heat test is 91% or more, and is excellent also about the transmittance | permeability. Therefore, the transparent electrode of Examples 15-16 is useful as an electrode of a heat resistant touch panel.

(Examples 17-18, Comparative Examples 9-10)
A transparent electrode was prepared and evaluated in the same manner as in Examples 13 to 14 except that an In—Si—O system or an In—Si—Sn—O system was selected as the second layer thin film. The target was produced as follows. The substrate temperature during film formation by sputtering was 200 ° C.
(9) In-Si-O-based transparent conductive film production target A predetermined amount of indium oxide powder and cerium oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered to contain titanium. An indium oxide sintered body was prepared. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
(10) In-Si-Sn-O-based transparent conductive film production target A predetermined amount of indium oxide powder, cerium oxide powder, and tin oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered. Thus, an indium oxide sintered body containing titanium was produced. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
The evaluation results are shown in Table 3.

In Comparative Examples 9 to 10, since the second layer In—Si— (Sn—) O-based thin film is a crystalline film, the change in the surface resistance value before and after the 1 hour heating test at 150 ° C. in the atmosphere (R / R ₀ ) has deviated from the range of 0.80 to 1.20. The transparent electrodes as in Comparative Examples 9 to 10 have a remarkable change in resistance value in the heating step (150 ° C.) when the electrode and the lead electrode are applied with a silver paste and cured when the touch panel is manufactured. , It cannot be produced with uniform and stable characteristics. On the other hand, in Examples 17 to 18, since the second In-Si- (Sn-) O-based thin film is covered with an amorphous film, the change in resistance value is within that range. Moreover, the average transmittance | permeability of the visible region of the transparent electrode itself before a heat test is 91% or more, and is excellent also about the transmittance | permeability. Therefore, the transparent electrodes of Examples 17 to 18 are useful as electrodes for touch panels that require heat resistance.

(Examples 19-22, Comparative Examples 11-14)
Even when the following In—W—Zn—O system, In—Zn—O system, and In—Ge—Sn—O system are selected as the second layer thin film, the same manner as in Examples 13 to 14 is used. Carried out. As shown in Tables 4 and 5, the results of the heat resistance test were the same. Moreover, the average transmittance | permeability of the visible region of the transparent electrode itself of Examples 19-22 before a heat test was 91% or more, and was excellent also about the transmittance | permeability.
(11) In-W-Zn-O-based transparent conductive film production target A predetermined amount of indium oxide powder, tungsten oxide powder, and zinc oxide powder are mixed in various proportions, the mixture is molded, and then heated and sintered. Thus, an indium oxide sintered body containing tungsten and zinc was produced. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
(12) In-Zn-O-based transparent conductive film production target A predetermined amount of indium oxide powder and zinc oxide powder are mixed in various proportions, and the mixture is molded, then heated and sintered to contain zinc. An indium oxide sintered body was prepared. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.
(13) In-Ge-Sn-O-based transparent conductive film production target A predetermined amount of indium oxide powder, germanium oxide, and tin oxide powder are mixed in various proportions, and the mixture is molded, then heated and sintered. Thus, an indium oxide sintered body containing germanium and tin was produced. These sintered bodies were processed into 6 inches Φ × 5 mmt, and bonded to a backing plate made of oxygen-free copper using an In-based alloy to obtain a sputtering target.

(Comparative Examples 15-23)
In Examples 1-7 and Examples 13-14, evaluation of the transparent electrode in the case where the second layer was not laminated was performed in the same manner. The results are shown in Table 6. In any of the heating tests at 200 ° C. and 150 ° C., the change in surface resistance is remarkable and cannot be used as a transparent electrode for a touch panel having excellent heat resistance.

(Comparative Examples 24-25)
In Examples 15 to 16, the transparent electrode was evaluated in the same manner when the first layer was not laminated. The results are shown in Table 7. Even in the heating test at 150 ° C., the change in surface resistance was small, and the transparent electrode was excellent in heat resistance. However, when a touch panel in Comparative Example 29 described later is assembled and a heat resistance and moisture resistance test is performed, film peeling off is severe and cannot be used as a transparent electrode for a touch panel.

(Comparative Examples 26-27)
In Examples 1 and 2, a laminated structure in which the first layer film and the second layer film are interchanged, that is, an amorphous transparent conductive film is formed on a substrate, and a crystalline transparent conductive film is stacked thereon. A transparent electrode having the above structure was prepared. The production conditions are the same as in Examples 1-2. Table 8 shows the structure of the transparent electrode and the change in resistance value when the heating test was performed in the same manner as in Examples 1 and 2. In the heating test at 200 ° C., the change in surface resistance was remarkable, and it was found that it could not be used as a transparent electrode for a touch panel having excellent heat resistance. In the heating test at 150 ° C., the same result was obtained, and the resistance value change was large.

(Comparative Example 28)
In Example 8, a transparent electrode film having the same laminated structure was produced except that the film thickness of the second layer of amorphous transparent conductive film was changed to 20 nm. The change in resistance value when the heating test was performed in the same manner as in Example 8 was a transparent electrode having a small and excellent heat resistance as in Example 8, but before the heating test in the same manner as in Example 8. The average transmittance in the visible region of the measured transparent electrode itself was 88%, which was inferior in permeability compared to the examples. Therefore, it cannot be used as a transparent electrode for a touch panel that places importance on visibility.

(Example 23)
Using the glass substrate with a transparent electrode obtained in Examples 1 to 22, an analog touch panel as shown in FIG. 2 was produced by a conventional method.
First, the upper electrode (6) which consists of the glass-made board | substrates (3-1) in which the transparent electrode (4-1) of Examples 1-22 was formed is prepared, and it forms in the formation surface of a transparent electrode (4-1). Then, resist printing, etching, silver ink printing and insulating ink printing were performed, and parallel electrodes and routing circuits were formed. Then, it printed with the electroconductive heat seal ink, bonded together using the double-sided tape, and was punched out, and it was set as the electrode. Similarly, the lower electrode 9 provided with the transparent conductive film (4-2) on the glass substrate (3-2) was also connected to the parallel electrode to produce a circuit. With the transparent electrode faces facing each other, spherical spacers (5, 9) with a diameter of 7 μm are arranged at a density of 100 pieces / mm ² , the upper and lower electrodes are bonded together with a spacing of 7 μm, and heat sealing is performed. The touch panel was manufactured by electrical connection.
The assembly of the touch panel includes a heating step, but the resistance value distribution (so-called linearity) of the obtained touch panel was good. This is considered because the favorable linearity of the transparent conductive film of Examples 1-22 excellent in heat resistance is maintained.
A test that repeats the action of pressing the surface of the touch panel 500 times for 2 seconds after applying a pressure 1.96N (200 g) to an area of 1 mm ² after performing a heat resistance test (90 ° C., 24 h) on the manufactured touch panel (Hereinafter referred to as a push test). When the surface state of the touch panel before and after the test was observed visually and with a microscope, it was found that there was no film peeling and the heat resistance was extremely excellent.
Further, as a moisture resistance test, a sheet resistance was applied to the transparent conductive film on the side to which a positive potential was applied after applying a potential of 8 V for 250 hours between the electrodes of the cell in an atmosphere of 60 ° C. and 95% RH. When the value was measured and the ratio with the initial sheet resistance value was calculated and judged, it was 1.02 to 1.05, the change was very small, high visible light transmittance was maintained, and the moisture resistance was extremely high. It was good.

(Example 24)
The same as Example 23, except that a commercially available resin film with a transparent conductive film (trade name: 300RK, manufactured by Toyobo Co., Ltd., film material: PET, transparent conductive film: ITO film, thickness 125 μm) was used for the upper electrode. As a result, the heat resistance and moisture resistance were good as in Example 23.

(Comparative Example 29)
In the same manner as in Example 23, a touch panel was assembled using the glass substrate on which the transparent electrodes of Comparative Examples 1 to 27 were formed, and heat resistance and moisture resistance tests were performed.
In the heat resistance test of the touch panel, when visual observation after the push test and observation with a microscope were performed, film peeling was observed to be noticeably clouded, and a decrease in transmittance was observed.
Therefore, it cannot be used as a touch panel as an application requiring heat resistance such as an in-vehicle car navigation system.

It is explanatory drawing which shows the cross-section of the board | substrate which laminated | stacked the transparent electrode of this invention. It is the schematic which shows the transparent touch panel (sectional structure) of the structure where the lower electrode and the upper electrode were laminated | stacked through the spacer. It is a cross-sectional TEM image of the transparent electrode of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crystalline transparent conductive film 2 Amorphous transparent conductive film 3 Substrate 4 Transparent electrode 5 Spacer 6 Upper electrode 7 Grain boundary 9 Lower electrode 10 Pen

Claims (11)

  A transparent electrode having a laminated structure in which a crystalline transparent conductive film (A) mainly composed of indium oxide and an amorphous transparent conductive film (B) mainly composed of indium oxide are sequentially formed on a substrate (C). The crystalline transparent conductive film (A) has a thickness of 5 to 40 nm, the amorphous transparent conductive film (B) has a thickness of 2 to 10 nm, and the surface resistance is 70 to 3000 Ω / □. A transparent electrode characterized by being.   The crystalline transparent conductive film (A) is indium oxide containing at least one additive element (Me) selected from tin or titanium, and the total content thereof is 0.01 to Me / In atomic ratio. The transparent electrode according to claim 1, which is 0.15. The amorphous transparent conductive film (B) is indium oxide containing at least one additive element (Me) selected from gallium, cerium, silicon, germanium, tungsten, or zinc, and its content is Me ₂ as a total amount. The transparent electrode according to claim 1, wherein the / In atomic ratio is 0.04 to 0.80.   4. The transparent electrode according to claim 3, wherein the crystallization temperature of the amorphous transparent conductive film (B) is 250 ° C. or higher.   The transparent electrode according to claim 1, wherein the substrate (C) is any one of a transparent substrate selected from a glass plate, a plastic resin plate, and a resin film.   The crystalline transparent conductive film (A) and the amorphous transparent conductive film (B) are sequentially formed on the substrate (C) heated to 200 ° C. or higher by a sputtering method. The transparent electrode in any one. The rate of change in surface resistance (R / R ₀ , where R: surface resistance after a heat resistance test heated in air at 150 ° C. or higher for 1 hour, R ₀ : surface resistance before test) is 0.80 The transparent electrode according to claim 1, which is ˜1.20.   The transparent electrode according to claim 7, wherein the transparent electrode is heated to 200 ° C. in the heat resistance test.   The transparent conductive substrate in which the transparent electrode in any one of Claims 1-8 is formed in the surface of a transparent substrate.   A transparent touch panel using the transparent conductive substrate according to claim 9 as a lower electrode and / or an upper electrode.   11. The transparent touch panel according to claim 10, wherein the lower electrode and the upper electrode are laminated so as to face each other with a spacer interposed therebetween.

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