JPH1034797A - Transparent conductive laminate and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve anti-environmental property with inexpensive metal by laminating a transparent conductive thin film layer consisting mainly of indium oxide on one major surface of a transparent polymeric substrate, and laminating a metal thin film layer consisting of copper after the lapse of a specific period of time and being exposed in an atmospheric ambient once. SOLUTION: A transparent conductive film layer consisting mainly of at least indium oxide is laminated on one major surface of a transparent polymeric substrate, e.g. polyethylene terephthalate film. The transparent conductive film layer is formed mainly of indium oxide; however, it may contain 3-50wt.% tin allowing for lowering of resistivity or improvement of the film quality. In the next place, after forming the transparent conductive film layer, e.g. five seconds later, gas used during the period of forming indium tin oxide is interrupted for laminating a metal thin film layer consisting of copper as a second layer as maintaining the degree of vacuum. After the formation of the transparent conductive film layer, it is exposed in atmosphere once to then be evacuated again so as to form a metal thin film layer consisting of copper as a second layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent conductive laminate and a method for producing the same. More specifically, the present invention relates to a transparent conductive laminate excellent in environmental resistance, which can be suitably used as a transparent electrode of an electroluminescence display, and a method for producing the same.

[0002]

2. Description of the Related Art A transparent conductive laminate is used as an electrode of a display element such as a liquid crystal display, an electroluminescence display, an electrochromic display, an electromagnetic wave shielding film of an electromagnetic wave shield, or an electrode of an input device such as a transparent touch panel. . As a conventionally known transparent conductive laminate, a laminate of a metal thin film such as gold, palladium, and platinum and an oxide thin film such as indium oxide, tin oxide, and zinc oxide is known.

An electroluminescent display is based on a transparent conductive substrate having a transparent conductive film formed on a transparent substrate, and a luminescent layer, an insulating layer, and a back electrode are sequentially formed on the transparent conductive film. Structures coated with layers are well known. The light-emitting layer is made of zinc sulfide, cadmium sulfide, zinc selenide, etc., the insulating layer is made of yttrium oxide, silicon nitride, thallium oxide, etc. having a high dielectric constant, and the back electrode is made of aluminum. .

The transparent conductive substrate is required to have excellent transparency in order to emit the visible light emitted from the light emitting layer to the outside without waste, and to be able to withstand long-time use.

[0005] Conventional transparent conductive substrates are mainly glass substrates. By heating the substrate to a high temperature, a chemically stable transparent conductive film layer is formed, which is excellent in transparency and environmental resistance. A transparent conductive substrate was easily obtained. However, the glass substrate has problems such as cracking, heavy weight, and thickness, and there has been a strong demand for a transparent electrode using a polymer substrate that can solve this problem.

[0006]

However, when a transparent polymer substrate is used, when forming a transparent conductive film layer, the substrate temperature is limited to the heat-resistant temperature of the polymer substrate. Not get. Therefore, it is not easy to form a transparent conductive film layer having excellent environmental resistance.

As a transparent conductive substrate for electroluminescence, at least 75% or more of visible light and a surface resistance of 1
000Ω / □ or less is required. When a transparent conductive film layer mainly composed of indium oxide is formed to a thickness of 10 nm or more, visible light and surface resistance are satisfied. However, when this is used as a transparent electrode for an electroluminescence display, the luminescent layer and the transparent conductive film layer are in direct contact. Therefore, there is a problem in that if the voltage is applied and the device is used for a long period of time, the interface is deteriorated and the light emission luminance is reduced at an early stage.

As a method of suppressing the deterioration of the interface, a method of laminating a palladium thin film on a transparent conductive film layer (Japanese Patent Laid-Open No.
No. 18254) was developed, but the industry has strongly demanded the development of a transparent conductive substrate for an electroluminescent display which is inexpensive and excellent in environmental resistance because of its expensive material.

On the other hand, the present inventors have proposed that a transparent conductive film layer (B) composed mainly of indium oxide and a metal thin film layer (C) composed mainly of copper are provided on one main surface of the transparent polymer substrate (A). It has been found that by forming a transparent conductive substrate, a transparent conductive substrate for an electroluminescence display having excellent environmental resistance can be provided at low cost. However, surprisingly, using a roll-to-roll type multipolar sputtering apparatus, a transparent conductive film layer (B) mainly composed of indium oxide and a metal thin film layer (C) mainly composed of indium oxide were formed on the polymer substrate (A). ) Formed continuously, it was found that the environmental resistance was likely to decrease.

The present inventors have conducted intensive studies on the cause, and as a result, a reaction between the indium component in the transparent conductive film layer and the copper component in the metal thin film layer resulted in the formation of a composite oxide of indium and copper. As a result, it has been found that deterioration occurs at the interface with zinc sulfide or cadmium sulfide as the electroluminescence light emitting layer, and the light emission luminance is attenuated early. Furthermore, after completely stabilizing the transparent conductive film layer, the metal thin film layer is formed, that is, after forming the transparent conductive film layer, after 5 seconds or more, the metal thin film layer is laminated,
Alternatively, after forming a transparent conductive film layer, once exposing it to the air atmosphere, and then laminating a metal thin film layer, it has been found that environmental resistance is remarkably improved.

An object of the present invention is to solve the problems that could not be solved by the prior art, that is, to improve the environmental resistance and to improve the visible light by establishing a method for manufacturing an inexpensive metal thin film laminate. The purpose is to produce a transparent conductive laminate having a surface resistance of 75% or more and a surface resistance of 1000Ω / □ or less.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the conventional problems, and as a result, at least one of the main surfaces of the transparent polymer substrate (A) has been mainly made of indium oxide. When the transparent conductive film layer (B) and the metal thin film layer (C) made of copper are laminated in an ABC configuration,
After the transparent conductive film layer is formed, after 5 seconds or more or once exposed to the air atmosphere, the manufacturing method of laminating the metal thin film layer makes it possible to produce a transparent conductive laminate excellent in environmental resistance with inexpensive metal. The present invention has been completed and the present invention has been completed.

The first gist of the present invention is that a transparent conductive film layer (B) mainly made of indium oxide is laminated on at least one main surface of a transparent polymer substrate (A). When laminating a metal thin film layer (C) made of copper on B), after forming the transparent conductive film layer (B), after elapse of 5 seconds or more, or once exposed to the air atmosphere, A second aspect of the present invention is a method for producing a transparent conductive laminate, comprising laminating (C) a transparent conductive laminate obtained by the above method, particularly a transparent electrode for a transparent electrode of an electroluminescence display. The third point is that a transparent conductive layer (B) mainly made of indium oxide is laminated at least on one main surface of the transparent polymer substrate (A). (B)
A transparent conductive laminate characterized in that a metal thin film layer (C) made of copper is laminated thereon and no crystal peak appears in X-ray diffraction analysis.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polymer substrate is not particularly limited, but examples thereof include polyethylene terephthalate, polyether sulfone, polyarylate, polyacrylate, polycarbonate, polyether ether ketone,
Examples include a polymer substrate made of a homopolymer such as polyethylene, polyester, polypropylene, polyamide, polyimide, or polyvinyl fluoride, and a copolymer of a monomer of these resins with a copolymerizable monomer.
These polymer substrates may be unstretched, uniaxially stretched, or biaxially stretched. In addition, known additives in the polymer substrate or on the surface, for example, a lubricant, an antistatic agent, a hard coat agent,
A moisture-proof coating agent, a gas barrier coating agent, a corrosive agent and the like may be added or laminated. Further, the polymer substrate may be subjected to a known surface treatment, for example, a corona treatment, a roughening treatment, an anchor coat, or the like. Although the thickness of the polymer substrate is not particularly limited, it is usually 10-25
0 μm is preferred.

The transparent conductive film layer is mainly formed of indium oxide, but may contain 3 to 50% by weight of tin to reduce the resistivity and improve the film quality. The film thickness is usually 10
~ 200 nm is preferred. Since this thickness affects the surface resistance and the visible light transmittance, the thickness is determined by the required surface resistance and visible light transmittance.

As a method for forming the transparent conductive film layer, any of the conventionally known techniques such as a vacuum deposition method, a sputtering method and an ion plating method can be adopted. In the sputtering method, indium oxide containing indium oxide or tin may be used as a target, or indium or an indium tin alloy may be used.

The above-described film forming method can also be used for forming a metal thin film layer made of copper. The thickness is usually preferably 1 to 20 nm. If it is thinner than 1 nm, the effect of environmental resistance is small, and if it is thicker than 20 nm, transparency is impaired. That is, the thickness is preferably as thin as possible in consideration of economy, as long as the environment resistance is not impaired.

The time from the formation of the transparent conductive film layer (B) to the formation of the metal thin film layer (C) is preferably 5 seconds or more. 5
If the time is less than seconds, a composite oxide of indium and copper is formed, which is not preferable. The presence of the composite oxide can be estimated by X-ray diffraction analysis by detecting a third crystal peak other than the indium and copper peaks. Further, when the metal thin film layer is once exposed to the atmosphere, the pressure may be returned to the atmospheric pressure.

The transparent conductive laminate obtained by the above method may be subjected to a heat treatment in order to further improve environmental resistance. The heat treatment temperature is usually 200 ° C. or less.

[0020]

The present invention will be described below in detail with reference to examples. Example 1 On one surface of a polyethylene terephthalate film having a thickness of 125 μm, 30 indium tin oxide was used as a first layer.
(The target used was an indium tin alloy containing 20% by weight of tin, the reaction gas was argon gas and oxygen gas introduced at a ratio of 10: 4, and the film was formed by DC magnetron sputtering under an atmosphere of 0.4 Pa. ). Five seconds later, the gas used during the formation of indium tin oxide was shut off, and 2 n of copper was used as the second layer while maintaining the degree of vacuum.
(reaction gas is introduced only argon gas,
A film was formed by DC magnetron sputtering under an atmosphere of 0.4 Pa) to produce a transparent conductive laminate having a two-layer structure.

Example 2 Example 1 was repeated except that after forming the first layer of Example 1, the film was once exposed to the atmosphere and then evacuated again to form the second layer of copper.
Under the same conditions as above, a transparent conductive laminate was produced.

Example 3 A transparent conductive laminate was produced under the same conditions as in Example 1 except that the thickness of the second layer copper was changed to 1 nm.

Example 4 A transparent conductive laminate was produced under the same conditions as in Example 1 except that the thickness of the second layer copper was changed to 5 nm.

Example 5 A transparent conductive laminate was produced under the same conditions as in Example 1 except that the thickness of the second layer copper of Example 1 was changed to 10 nm.

Example 6 The film thickness of the first layer of indium tin oxide of Example 1 was 10 n.
A transparent conductive laminate was produced under the same conditions as in Example 1 except that m was used.

Comparative Example 1 A transparent conductive laminate was produced under the same conditions as in Example 1 except that the first layer and the second layer of Example 1 were continuously manufactured.

Comparative Example 2 A transparent conductive laminate having a one-layer structure was produced under the same conditions as in Example 1 except that the second layer of Example 1 was not formed.

Comparative Example 3 A transparent conductive laminate was produced under the same conditions as in Example 1 except that the thickness of the second layer copper was 25 nm.

Comparative Example 4 The thickness of the first layer of indium tin oxide in Example 1 was 5 nm.
A transparent conductive laminate was produced under the same conditions as in Example 1 except for the above.

Comparative Example 5 The film thickness of the first layer of indium tin oxide of Example 1 was 300
A transparent conductive laminate was produced under the same conditions as in Example 1 except that the thickness was changed to nm.

The surface resistance, visible light transmittance and environmental resistance of the transparent conductive laminate produced as described above were evaluated by the following methods.・ Surface resistance (R, Ω / □): Measured by 4-terminal method ・ Visible light transmittance (Tvis%): Hitachi, Ltd.
Environmental resistance: An electroluminescent luminescent layer was prepared by the following steps, and a voltage of 100 V AC (frequency 1 kHz) was applied under an atmosphere of 50 ° C. and 60% RH to emit light. Let
The initial luminance at that time and the luminance change rate after 300 hours were evaluated. The luminance meter uses LS-110 manufactured by Minolta Co., Ltd. In the case of producing an electroluminescent luminescent material, a liquid in which zinc sulfide powder is dispersed in an acetone solution is applied onto the transparent conductive laminate, and then 60 C. for 2 hours, then 12
The light emitting layer was formed by performing a heat treatment at 0 ° C. for 2 minutes. Thereafter, a liquid in which barium titanate powder was dispersed in an acetone solution was further applied, and then heat treatment was performed at 60 ° C. for 2 hours to form a dielectric layer. Furthermore, aluminum having a thickness of 0.2 mm was overlaid thereon and heat-treated at 150 ° C. for 2 minutes. This was sandwiched between two moisture-proof films to obtain an electroluminescent luminescent material. Table 1 shows the evaluation results.

[0032]

[Table 1] Examples 1 to 6 and Comparative Example 2 in X-ray diffraction analysis
No third crystal peak was observed. Comparative Example 1,
In Comparative Examples 3 to 5, a third crystal peak was observed, and the presence of a composite oxide of indium and copper was estimated.

[0033]

According to the present invention, a transparent conductive film layer mainly composed of indium oxide is formed on one main surface of the transparent polymer substrate of the present invention as a first layer, and a metal thin film layer composed of copper is formed as a second layer in a separate step. By forming, a transparent conductive laminate suitable for a transparent electrode for electroluminescence having excellent environmental resistance can be provided.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuichiro Harada 2-1-1 Tango-dori, Minami-ku, Nagoya-shi, Aichi Inside Mitsui Toatsu Chemicals Co., Ltd. (72) Akira Suzuki 2-chome Tango-dori, Minami-ku, Nagoya-shi, Aichi No. 1 Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Akemi Nakajima 2-1-1 Tango-dori, Minami-ku, Nagoya-shi, Aichi Prefecture

Claims (5)

[Claims] 1. A transparent polymer substrate (A) having one main surface
At least a transparent conductive film layer (B) mainly made of indium oxide is laminated, and when a metal thin film layer (C) made of copper is laminated on the transparent conductive film layer (B), the transparent conductive film layer (B) is formed. A) forming a transparent conductive laminate, wherein the metal thin film layer (C) is laminated after elapse of 5 seconds or more or once exposed to the atmosphere. 2. The transparent conductive film layer (B) has a thickness of 10 to 2
The method for producing a transparent conductive laminate according to claim 1, wherein the thickness of the metal thin film layer (C) is 1 to 20 nm. 3. A transparent conductive laminate obtained by the method according to claim 1. 4. A transparent conductive laminate for a transparent electrode of an electroluminescence display obtained by the method according to claim 1. 5. The method according to claim 1, wherein one main surface of the transparent polymer substrate (A) is
At least a transparent conductive film layer (B) mainly composed of indium oxide is laminated, and a metal thin film layer (C) composed of copper is laminated on the transparent conductive film layer (B). A transparent conductive laminate having no crystal peak.