JP4187315B2 - Method for producing transparent conductive laminate for liquid crystal display - Google Patents

Description

【００３２】
【発明の効果】
本発明により、バッチ式、ロールツーロール方式を問わず、スパッタリング法を用いて高分子フィルムの両面に硬化樹脂層が設けられており、該硬化樹脂層の少なくとも一方の面上に金属酸化物層が設けられている高分子積層フィルムの該金属酸化物層上にスパッタリング法によって透明導電薄膜を形成するにあたり、成膜雰囲気中に存在する水分が常に9.0x10 ^-6 Torrから2.0x10 ^-5 Torrであるように水分を導入しながら成膜することによって耐アルカリ性の良好な液晶表示用透明導電積層体を得ることができた。
【図面の簡単な説明】
【図１】本発明の成膜方法を実施するための装置の構成図である。
【符号の説明】
1. 真空チャンバー
2. 長尺ロール状ポリマーフィルム
3. ターゲット
4. 巻きだし軸
5. メインロール
6. サブロール
7. 巻き取り軸[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a transparent conductive laminate for liquid crystal display, and more specifically, a polymer laminate in which a cured resin layer is provided on both sides of a polymer film and a metal oxide layer is provided on at least one side of the cured resin layer. The present invention relates to a method for producing a conductive laminate for liquid crystal, in which a transparent conductive thin film mainly composed of indium oxide is formed on a metal oxide layer of a film under specific conditions.
[0002]
[Prior art]
In recent years, portable information devices such as pagers, mobile phones, electronic notebooks, and portable information terminals have begun to spread. In order to improve the portability of these information devices, further reduction in thickness, weight, and damage resistance are required. Conventionally, glass substrates that are heavy, thick, and easy to break have been used as transparent electrode substrates for LCDs and touch panels, but transparent resin substrates have been proposed as alternative materials. However, the transparent resin substrate is inferior to the glass substrate in basic characteristics such as durability, solvent resistance, and gas barrier properties. For example, when a transparent resin substrate is used as an electrode substrate for an LCD, gas barrier properties can be imparted by providing a metal oxide layer. Also, when coating a coating solution in which the precursor material of the liquid crystal alignment film is dissolved in a solvent such as N-methylpyrrolidone during the liquid crystal alignment film formation process, the transparent resin substrate may be damaged by whitening, swelling, etc. There was a problem to receive. In order to solve such problems, the present inventors have provided a cured resin layer on both sides of a polymer film, and the metal oxide layer of a polymer laminated film in which a metal oxide layer is provided on at least one side thereof. A transparent conductive thin film mainly made of indium oxide has been formed thereon, and a transparent conductive laminate for liquid crystal display has been produced and studied.
[0003]
In general, an ITO (In-Sn-O) film is widely used as an electrode material for liquid crystal displays, touch panels, etc., taking advantage of its high conductivity and high transparency properties. In recent years, a DC magnetron sputtering method has become common as a method for forming this ITO film in terms of controllability of the film formation rate and uniformity of the formed thin film. In particular, recent progress in thin film formation technology has been remarkable, and it has become possible to form a transparent conductive thin film on a polymer film substrate having little heat resistance. Among these, the sputtering method is one of the most utilized techniques, having features such that film formation can be performed for a long time, composition does not shift even when film formation is performed for a long time, and widening is easy.
[0004]
The present inventors formed an ITO film on the polymer laminated film by using this sputtering method, and evaluated its practicality. In the process of manufacturing a liquid crystal display element, adhesive properties, heat resistance, and chemical resistance are generally required as necessary properties of a transparent conductive laminate for liquid crystal display. However, when an ITO (In-SnMetal) or ITO target is used to deposit a film on a metal oxide of a polymer laminated film by DC magnetron sputtering, the ITO thin film may have poor alkali resistance depending on the deposition conditions. there were.
[0005]
[Problems to be solved by the invention]
The object of the present invention is to provide a transparent conductive material for liquid crystal displays having good alkali resistance when continuously formed on a metal oxide layer of a polymer laminated film by magnetron sputtering using an ITM (In-SnMetal) or ITO target. It is in providing the manufacturing method which gives a laminated body.
[0006]
[Means for Solving the Problems]
In the present invention, a cured resin layer is provided on both surfaces of a polymer film, and a metal oxide layer is provided on at least one surface of the cured resin layer. In addition, in the method for producing a transparent conductive laminate for liquid crystal display in which a transparent conductive thin film is formed by sputtering, the partial pressure of water existing in the film forming atmosphere is in the range of 9.0 × 10 ⁻⁶ Torr to 2.0 × 10 ⁻⁵ Torr. A transparent conductive thin film having a good alkali resistance and suitable as a substrate for a liquid crystal display is characterized by forming a transparent conductive thin film while introducing water so as to be inside.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
A sputtering method is used as the method for forming the transparent conductive thin film in the present invention. In a sputtering method for forming a layer mainly containing indium oxide, an alloy containing indium as a main component or a sintered body containing indium oxide as a main component can be used as a target. The former performs reactive sputtering by introducing an inert gas such as argon and a reactive gas such as oxygen gas into the vacuum chamber. In the latter, sputtering is performed using an inert gas such as argon alone or a mixture of an inert gas such as argon and a reactive gas such as a minute amount of oxygen gas. As a sputtering method, a known method such as direct current or high frequency bipolar sputtering, direct current or high frequency magnetron sputtering, or ion beam sputtering can be applied. Among these, the magnetron method is preferable because it has less plasma impact on the substrate and enables high-speed film formation.
[0008]
Moreover, it can apply to both a batch type and a roll-to-roll system as a sputtering device. Considering the productivity, the roll-to-roll method is particularly preferable.
[0009]
The inventors of the present invention have repeatedly studied a transparent conductive laminate for liquid crystal display in which an ITO thin film is formed on the metal oxide layer of the polymer laminate film, but particularly in the required properties. It was difficult to satisfy the alkalinity. As a result of intensive studies, the present inventors have determined that the alkali resistance of the transparent conductive laminate for liquid crystal display is determined by the moisture pressure in the deposition atmosphere when forming the ITO thin film on the metal oxide layer of the polymer laminate film. I found out. This moisture was mainly released from the polymer film and the cured resin layer. Therefore, an inert gas, which is a conventionally introduced gas, is used to continuously manufacture a transparent conductive laminate for liquid crystal displays, which is formed by transporting a polymer laminated film and forming a transparent conductive thin film mainly composed of indium oxide. In addition to oxygen (mainly argon) and oxygen, the moisture content in the deposition atmosphere is monitored with a quadrupole mass spectrometer so that the moisture pressure is kept constant in the range of 3.0x10 ^-6 to 2.0x10 ^-5 Torr. It was found that by performing sputtering while adding moisture from outside the system, a transparent conductive laminate for liquid crystal display with good alkali resistance can be obtained without cracking or peeling in the ITO thin film after the alkali test. When the moisture (massnumber18) present in the film-forming atmosphere is less than 3.0x10 ^-6 Torr, cracks that can be visually confirmed occur in the ITO thin film after the alkali test, and the transparent conductive laminate for liquid crystal displays is used. Alkali resistance was poor. When water present in the deposition atmosphere (massnumber18) exceeds 2x10 ^-5 Torr and cracks occur enough to visually check the ITO film after the alkali test, also seen portion and which has been peeled off, for liquid crystal display Alkali resistance when used as a transparent conductive laminate was poor. When the moisture (massnumber18) in the film-forming atmosphere is in the range of 3.0x10 ^-6 Torr to 2x10 ^-5 Torr, the ITO thin film after the alkali test has no cracks or peeling, and the transparent conductive laminate for liquid crystal display is obtained. When the alkali resistance was good. Thus, it was found that the moisture pressure existing during the film formation has a great influence on the alkali resistance when the transparent conductive laminate for liquid crystal display is formed. When moderate water is added to the film formation atmosphere and ITO is deposited on a metal oxide layer such as SiOx with the water content within the above range, the introduction of such water alleviates stress at the interface between ITO and SiOx. As a result, it is considered that the adhesion of ITO on SiOx is improved and the alkali resistance is improved. If the partial pressure is less than the above range, the ITO thin film itself has a very high film stress, and the adhesiveness at the interface with SiOx is deteriorated, so that it is considered that cracks occur. Further, if the partial pressure exceeds the above range, the ITO thin film itself becomes a film that is weak against alkali, so it is considered that the ITO thin film cracks and peels off.
[0010]
The transparent conductive thin film used in the present invention mainly contains indium oxide. Indium oxide is essentially a transparent electrical insulator, but becomes a semiconductor when (1) it contains a small amount of impurities, or (2) it is slightly oxygen deficient. As a preferable semiconductor metal oxide, for example, indium oxide containing tin or fluorine as an impurity can be given. An indium oxide thin film containing 2 to 20% by weight of tin oxide is particularly preferable. The thickness of the transparent conductive thin film mainly containing indium oxide used in the present invention is preferably 100 mm or more in order to obtain sufficient conductivity. The upper limit is not particularly limited, but is about 3000cm.
[0011]
The polymer film in the present invention is not particularly limited as long as it is a transparent organic polymer compound having heat resistance. Usually, the heat resistance is 100 ° C. or higher, preferably 130 ° C. or higher. , Polycarbonate, polysulfone, polyarylate, polyester, polyamide, polyimide, polyolefin and the like. Of course, they can also be used as homopolymers, copolymers, alone or as a blend.
[0012]
Such a polymer film includes a film. The thickness of such a polymer film is usually 10 to 1000 μm.
[0013]
Examples of the metal oxide layer in the present invention include metal oxides mainly composed of one or more metals selected from the group of silicon, aluminum, magnesium and the like, and are known as materials having excellent gas barrier properties. It has been. These oxide layers are formed by sputtering, ion plating, plasma CVD, or the like.
[0014]
Among these, metal oxides mainly composed of silicon oxide having a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0 from the viewpoint of gas barrier properties, transparency, surface smoothness, flexibility and the like are good. The ratio of the number of oxygen atoms to silicon oxide is analyzed and determined by X-ray electron spectroscopy, X-ray microspectroscopy, Auger electron spectroscopy, Rutherford backscattering method, and the like. When this ratio is less than 1.5, the transparency is deteriorated, so 1.5 to 2.0 is preferable.
[0015]
The thickness of the metal oxide layer is preferably in the range of 5 nm to 200 nm. When the thickness is less than 5 nm, it is difficult to form a film uniformly, and a portion where the film is not formed is generated. Gas permeates from this portion, resulting in poor gas barrier properties. On the other hand, when it is thicker than 200 nm, not only the transparency is lost, but also the flexibility is poor, and cracks are generated to deteriorate the gas barrier property.
[0016]
For higher transparency requirements, the above silicon oxide SiOx (x is 1 to 2) containing 5 to 30% by weight of magnesium fluoride with respect to the total weight is preferable.
[0017]
The cured resin layer in the present invention has good adhesion to the polymer film and the metal oxide layer, and preferably has chemical resistance and flex resistance. In order for the cured resin layer to reduce curl deformation of the polymer laminated film used in the present invention, it is preferable to apply the same resin layer to both sides of the polymer film so that the film thickness is substantially equal.
[0018]
Specific examples of such a cured resin layer include an epoxy resin, an acrylic resin, an acrylic epoxy resin, a melamine resin, a phenol resin, or a urethane resin as a thermosetting resin. Examples of the photopolymerizable polymer include polyester acrylate, polyester urethane acrylate, and polyol acrylate. You may use these in mixture of 2 or more types.
[0019]
In addition, as a layer structure of the polymer laminated film in this invention, a cured resin layer / polymer film / cured resin layer / metal oxide layer / ITO layer can be mentioned, for example. An anchor coat layer can be interposed between the cured resin layer and the polymer film or between the cured resin layer and the metal oxide layer in order to improve adhesion and the like.
[0020]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[0021]
(1) Quadrupole mass spectrometer The quadrupole mass spectrometer used in the present invention is an apparatus that mainly evaluates the types and abundances of elements present in a vacuum chamber. In the present invention, this quadrupole mass spectrometer is used as a partial pressure gauge. The equipment used this time is the MicropoleAnalyzer ultra-compact partial pressure vacuum gauge system MPA manufactured by MC Electronics. As the MPA sensor, model number MPA-CF-215 with a maximum operating pressure of 5 mTorr and an analytical mass range of 2 to 100 AMU was used this time.
[0022]
(2) Evaluation of alkali resistance Alkaline resistance is determined by immersing the sample in a 3.5 wt% NaOH aqueous solution at 30 ° C for 10 minutes, washing it thoroughly with running water, drying it, and visually observing the appearance. When no change was confirmed, it was evaluated as having alkali resistance.
[0023]
(3) ITO Film Formation Method FIG. 1 is a block diagram of an apparatus for carrying out the film formation method of the present invention. Set various polymer laminated film rolls as a substrate film on the unwinding shaft 4 and unwind the film so that it can be wound on the winding core set on the winding shaft 7 along the film formation path shown in the figure. To do.
[0024]
[Example 1]
As the polymer film, a polycarbonate film having a thickness of 100 μm and a Tg of 150 ° C. measured by DSC was used. A radiation curable resin layer having a thickness of 5 μm was provided on both surfaces of the polycarbonate film. As a radiation curable resin layer, roll a solution of Aronix M400 and M8030 manufactured by Toa Synthetic Chemical Co., Ltd. in a ratio of 1: 1, 7 phr of Igalcure 184 manufactured by Ciba Geigy Co., Ltd. as photocuring agent, and 0.1 phr of SH28PA as leveling agent. Coating was performed using a bar RDS10, and UV curing was performed using a 160 W / cm high-pressure mercury lamp with an integrated light amount of about 700 mJ / cm ² . The polymer film laminated with the cured resin layer thus obtained was placed in a take-up magnetron sputtering apparatus and evacuated to 2 × 10 ⁻⁵ Torr. Then, after introducing O ₂ / Ar mixed gas (O ₂ / Ar = 30%) into the tank at 100 sccm and maintaining the pressure at 2.0x10 ^-3 mTorr, the target was Si (B-doped) target. A metal oxide layer made of silicon oxide is formed on the cured resin layer by continuously forming a roll at room temperature, a film speed of Vf = 1.0 m / min, and an input power density of 1 W / cm ^2. As a result, a polymer laminated film having a film formed thereon was obtained.
[0025]
After that, the Si target was replaced with an ITO target and exhausted. The ultimate vacuum before film formation was 3 × 10 ⁻⁶ Torr. After that, 150 sccm of O ₂ / Ar mixed gas (O ² /Ar=1.2%) was introduced into the tank, the pressure was maintained at 3.0x10 ^-3 Torr, the main roll temperature was room temperature, and the film speed was Vf = 0.1 m / min and input power density were set to 1 W / cm ² . Moisture (massnumber18) present in the film-forming atmosphere at that time is observed with a quadrupole mass spectrometer (MPA), and water is introduced so that the water pressure is 9x10 ^-6 Torr. A transparent conductive laminate was obtained by continuously forming an ITO layer on the metal oxide layer. Table 1 shows the evaluation results of the obtained transparent conductive laminate. It was a transparent conductive laminate having excellent alkali resistance.
[0026]
[Example 2]
The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was placed in a take-up magnetron sputtering apparatus and evacuated to 3 × 10 −6 Torr. Then, O ₂ / Ar mixed gas (O ₂ /Ar=1.2%) was introduced 150sccm in the tank, after the pressure was kept 3.0x10 ^-3 Torr, room temperature of the main roll, the film speed Vf = 0.1 Continuous film formation was performed by setting m / min and input power density to 1 W / cm ² . Transparent conductivity by continuously forming the film while introducing moisture so that the partial pressure by the quadrupole mass spectrometer (MPA) of the moisture (massnumber18) present in the deposition atmosphere at that time is 1.2x10 ^-5 Torr A conductive laminate was obtained. Table 1 shows the evaluation results of the obtained transparent conductive laminate. It was a transparent conductive laminate having excellent alkali resistance.
[0027]
[Example 3]
The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was placed in a take-up magnetron sputtering apparatus and evacuated to 3 × 10 ⁻⁶ Torr. After that, 150sccm of O ₂ / Ar mixed gas (O ₂ /Ar=1.2%) was introduced into the tank and the pressure was maintained at 3.0x10-3Torr, then the temperature of the main roll was room temperature and the film speed was Vf = 0.1m / min and the input power density were set to 1 W / cm ² for continuous film formation. Transparent conductivity by continuously forming the film while introducing moisture so that the partial pressure by the quadrupole mass spectrometer (MPA) of the moisture (massnumber18) present in the film-forming atmosphere is 2.0x10 ^-5 Torr A conductive laminate was obtained. Table 1 shows the evaluation results of the obtained transparent conductive laminate. It was a transparent conductive laminate having excellent alkali resistance.
[0028]
[Comparative Example 1]
The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was placed in a take-up magnetron sputtering apparatus and evacuated to 3 × 10 ⁻⁶ Torr. After that, 150 sccm of O ₂ / Ar mixed gas (O ₂ /Ar=1.2%) was introduced into the tank, the pressure was maintained at 3.0x10 ^-3 Torr, the main roll temperature was room temperature, and the film speed was Vf = 0.1 Continuous film formation was performed by setting m / min and input power density to 1 W / cm ² . Laminate by successively formed while introducing water so that the partial pressure due to the quadrupole mass spectrometer (MPA) water (massnumber18) present in the deposition atmosphere at that time is 2.9x10 ^-5 Torr Got. The evaluation results of the obtained laminate are also shown in Table 1. Cracks that could be visually confirmed occurred on the ITO thin film after the alkali test, and the peeled part was also observed, resulting in poor alkali resistance.
[0029]
[Comparative Example 2]
The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was placed in a take-up magnetron sputtering apparatus and evacuated to 1 × 10 ⁻⁶ Torr. After that, 150 sccm of O ₂ / Ar mixed gas (O ₂ /Ar=1.2%) was introduced into the tank, the pressure was maintained at 3.0x10 ^-3 Torr, the main roll temperature was room temperature, and the film speed was Vf = 0.1 Continuous film formation was performed by setting m / min and input power density to 1 W / cm ² . Transparent conductivity by continuously depositing moisture while introducing moisture so that the partial pressure of the moisture (massnumber18) in the deposition atmosphere at that time by the quadrupole mass spectrometer (MPA) is 2x10 ^-6 Torr A laminate was obtained. The evaluation results of the obtained laminate are also shown in Table 1. The ITO thin film after the alkali test had cracks that could be visually confirmed, and the alkali resistance was poor.
[0030]
[Comparative Example 3]
The polymer laminated film provided with the cured resin layer and the metal oxide layer shown in Example 1 was placed in a take-up magnetron sputtering apparatus and evacuated to 1 × 10 ⁻⁶ Torr. After that, 150 sccm of O ₂ / Ar mixed gas (O ₂ /Ar=1.2%) was introduced into the tank, the pressure was maintained at 3.0x10 ^-3 Torr, the main roll temperature was room temperature, and the film speed was Vf = 0.1 Continuous film formation was performed by setting m / min and input power density to 1 W / cm ² . The laminated body is formed by continuous film formation while introducing moisture so that the partial pressure of the water (massnumber18) in the film formation atmosphere at that time is 1x10 ^-6 Torr by the quadrupole mass spectrometer (MPA). Obtained. The evaluation results of the obtained laminate are also shown in Table 1. The ITO thin film after the alkali test had cracks that could be visually confirmed, and the alkali resistance was poor.
[0031]
[Table 1]

[0032]
【The invention's effect】
According to the present invention, a cured resin layer is provided on both surfaces of a polymer film using a sputtering method regardless of batch type or roll-to-roll method, and a metal oxide layer is formed on at least one surface of the cured resin layer. When the transparent conductive thin film is formed on the metal oxide layer of the polymer laminated film provided with a sputtering method, the moisture present in the film formation atmosphere is always 9.0 × 10 ⁻⁶ Torr to 2.0 × 10 ⁻⁵ Torr. A transparent conductive laminate for liquid crystal display having good alkali resistance could be obtained by forming a film while introducing moisture.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an apparatus for carrying out a film forming method of the present invention.
[Explanation of symbols]
1. Vacuum chamber
2. Long roll polymer film
3. Target
4. Unwinding shaft
5. Main role
6. Sub-roll
7. Winding shaft

Claims (3)

A cured resin layer is provided on both surfaces of the polymer film, and a metal oxide layer is provided on at least one surface of the cured resin layer. In the method for producing a transparent conductive laminate for a liquid crystal display in which a transparent conductive thin film is formed by water, water is adjusted so that the partial pressure of water in the film forming atmosphere is in the range of 9.0 × 10 ⁻⁶ Torr to 2.0 × 10 ⁻⁵ Torr. A method for producing a transparent conductive laminate for liquid crystal display having good alkali resistance, characterized in that a transparent conductive thin film is formed while introducing.   The transparent conductive thin film for liquid crystal display according to claim 1, wherein the transparent conductive thin film contains indium oxide as a main component and contains at least one oxide selected from tin, zinc and gallium. Method.   The metal oxide layer is mainly composed of silicon oxide having a thickness of 5 to 200 nm and a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0. Or the manufacturing method of the transparent conductive laminated body for liquid crystal displays of 2.

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