JP2005093318A - Manufacturing method and flattening method of transparent conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive film having no surface with spike-like projections and having excellent surface smoothness for use in a transparent electrode such as a touch panel and an organic EL display for a flat panel display, and the like. A method of smoothing the surface of a transparent conductive film without changing the transparent conductive film forming line is provided.
A transparent conductive film in which a transparent conductive film is laminated on a transparent polymer film provided with a hard coat on at least one side through an underlayer, and the center line is polished by polishing the surface of the transparent conductive film. An average surface roughness Ra of 1 nm or less, a 10-point average roughness Rz of 10 nm or less, and a maximum height Rmax of 10 nm, and a method for smoothing the surface of the transparent conductive film.
[Selection] Figure 1

Description

  The present invention is a method for producing a transparent conductive film having no surface with spike-like projections and excellent surface smoothness for use in transparent electrodes such as flat panel displays such as touch panels and organic EL displays. Moreover, it is related with the method of smoothing the surface of a transparent conductive film, without changing the conventional transparent conductive film manufacturing line.

Transparent conductive films are widely used as transparent electrodes for Sn-doped In ₂ O ₃ (ITO) films, antistatic films, heat ray reflective films, surface heating elements, photoelectric conversion elements, touch panels and various flat panel displays. Transparent conductive films for LCD and other flat panel displays are strongly required to have low resistance and high transmittance. As a material for transparent conductive films, low resistance can be realized and pattern formation by wet etching is easy. Therefore, ITO is most widely used.

  Up to now, transparent conductive films have been formed on glass and used. However, in order to develop EL displays and flexible displays for which demand for mobile devices has recently been increasing and future development is expected, they are lightweight and flexible. There is an increasing demand for transparent conductive films in which a transparent conductive film is formed on a characteristic polymer film. Furthermore, taking advantage of the feature of being flexible, the transparent conductive film is also used as an upper electrode of a touch panel.

  As a method for forming the transparent conductive film on the film, a physical forming method such as a vacuum deposition method, a sputtering method, or an ion plating method is used. Among these, the sputtering method can relatively easily obtain a transparent conductive film having a desired resistance value by controlling the film forming atmosphere, and can be relatively easy due to the increase in the size of the target with respect to the increase in area of the substrate. Therefore, it is the mainstream of the current transparent conductive film manufacturing method.

  When the formed transparent conductive film is crystalline, the surface of the transparent conductive film including ITO formed by sputtering has a characteristic structure called a domain structure (Yuzo Shigesato, Yasui Toru, Applied Physics Vol. 64, No. 12, p1225-1229 (1995)), spike-like protrusions are formed. When an ITO film is formed by sputtering while keeping the polymer film at room temperature or lower, the formed ITO film has a structure in which amorphous and fine crystal grains are mixed. It becomes a protrusion.

  The average roughness Ra of the transparent conductive film having protrusions on the surface is about 5 nm to 20 nm, and when the transparent conductive film is used as the transparent electrode of the liquid crystal display, it is large if the resistance is low and the transmittance is high. Although it is not a problem, in recent organic EL device applications, in addition to low resistance and high transmittance, surface smoothness is strongly demanded, and the transparent conductive film having protrusions on the surface as described above is used as a transparent electrode. Can not do it. The organic EL device is a current injection type device, the organic thin film is as thin as about 100 nm to 200 nm, the low molecular weight material is formed by vapor deposition, and is easily affected by the shape of the base, etc. For this reason, if there are protrusions on the surface of the transparent electrode, current concentration occurs, leading to dark spots and increased leakage current.

  When using a transparent conductive film as an electrode for a contact resistance touch panel, the upper electrode made of a transparent conductive film and the lower electrode made of glass with a transparent conductive film come into contact with each other at the time of input. If there is a protrusion on the spike, the upper electrode may be damaged and peeled off during input. Further, if there are protrusions on the upper and lower electrodes, the protrusions may be scraped and the resistance at the time of contact may vary with time as the input is repeated. In addition, when the spike-like protrusions on the upper and lower electrode surfaces are large, the upper electrode and the lower electrode are in contact with each other even under a low load, which may cause a malfunction of the touch panel.

In order to solve the above problems, materials other than mainstream ITO have been studied as a transparent conductive film. In Japanese Patent Application Laid-Open No. 09-092037, In and Zn are used as main cation elements, and the atomic ratio of In and Zn. It is made of an amorphous oxide that is contained so that In / (In + Zn) is 0.8 or more and less than 0.9, the specific resistance is 2.0 × 10 ⁻⁴ Ω · cm or less, and the surface unevenness is 10 nm. The transparent conductive film which is the inside is provided on the transparent substrate, and the electroconductive transparent base material characterized by the above-mentioned is proposed. The In-Zn-O-based amorphous oxide thin film proposed in the publication can realize both surface smoothness and low specific resistance, and can be easily patterned by wet etching, and the patterning edge is sharp. Although there is an advantage, there is a disadvantage that the technology and experience that have been cultivated so far cannot be effectively used because it is necessary to change the transparent conductive film from an ITO thin film to an In—Zn—O-based thin film.

Japanese Patent Laid-Open No. 2001-307553 discloses that a sputtering target substantially consisting of In, Sn, Ge, and O is sputtered with a sputtering power in which rf is superimposed on dc, and has a resistivity of 2.5. A method for producing a transparent conductive film has been proposed in which × 10 ⁻⁴ Ω · cm or less and the maximum height difference (Z-Max) / film thickness (t) of surface irregularities satisfy 10% or less. When a transparent conductive film is formed by sputtering, a dc power supply is used in most production lines from the viewpoint of controllability and formation speed. In the method proposed in the publication, a new power supply is used. There are disadvantages such as introduction or modification. Furthermore, since the target contains an expensive Ge element, there is a problem that it is more effective than the ITO target.

Japanese Patent Application Laid-Open No. 2002-047559 includes a plasma beam generation source and a hearth disposed in a vacuum vessel and having a plasma beam incident surface, and is disposed concentrically with respect to the central axis of the hearth in the vicinity of the hearth. A stationary magnetic field is formed by the annular permanent magnet, and an adjustment magnetic field is superimposed on the stationary magnetic field by an electromagnetic coil arranged concentrically with the central axis of the hearth to change the magnetic field in the vicinity of the hearth, It is manufactured by an ion plating method in which a plasma beam from a plasma beam generation source is guided to an evaporation material for forming an ITO film accommodated in the hearth to form an ITO film on a substrate, and has a specific resistance of 4 × 10 ^−4. An ITO film characterized by an Ω · cm or less and a centerline average surface roughness Ra of 1 nm or less has been proposed. According to the ITO film proposed in the same publication and its manufacturing method, both surface smoothness and low specific resistance can be realized, but at present, the sputtering method is used for most ITO lines. However, the manufacturing method proposed in this publication requires a large capital investment, and further has the disadvantage that the technology and experience cultivated by the sputtering method so far cannot be used effectively.

JP 09-092037 A JP 2002-047559 A JP 2001-307553 A Yuzo Shigesato, Yasui, Applied Physics Vol. 64, No. 12, p1225-1229 (1995)

The present invention has been made to solve the above-described problems, and has no spike-like protrusions on the surface for use in transparent electrodes such as flat panel displays such as touch panels and organic EL displays. Providing a transparent conductive film having excellent surface smoothness, and
Provides a method for smoothing the surface of a transparent conductive film without changing the existing transparent conductive film forming apparatus and transparent conductive film forming process, and there is no spike-like protrusion on the surface, and the surface smoothness is excellent An object of the present invention is to provide a transparent conductive film.

  That is, in the present invention, a transparent base film is provided with a hard coat layer, a transparent conductive film is provided on the hard coat layer via an underlayer, and the surface of the transparent conductive film has a center line average surface roughness Ra of 1 nm. Hereinafter, a transparent conductive film having a flat surface is obtained by polishing a 10-point average roughness Rz to 10 nm or less and a maximum height Rmax to 10 nm or less. .

The present invention is also a method for planarizing the surface of a transparent conductive film provided on a transparent base film provided with a hard coat layer via an underlayer, wherein the surface of the transparent conductive film is coated with Al ₂ O ₃ , CeO. ₂ , center line average roughness obtained by coating a tape substrate with fine particles having a particle diameter of 0.1 to 1 μm made of at least one substance selected from the group consisting of ₂ , Cr ₂ O ₃ , Fe ₂ O ₃ , SiO ₂ and SiC. With a polishing tape having a Ra 0.03 to 1.00 μm, a 10-point average roughness Rz 0.8 to 4.0 μm, and a maximum height Rmax 1 to 5 μm, the center line average surface roughness Ra of the surface of the transparent conductive film is 1 nm or less. A method for planarizing the surface of a transparent conductive film, comprising polishing the point average roughness Rz to 10 nm or less and the maximum height Rmax to 10 nm or less.
This invention is also the transparent conductive film obtained by the above-mentioned manufacturing method.

The present invention has the following advantages.
(A) Since the surface of the transparent conductive film is smoothed by polishing after forming the transparent conductive film, it is not necessary to change the transparent conductive film formation line.
(A) Since a film on which a single-sided or double-sided hard coat of a polymer base film is formed is used, it is difficult for polishing marks to remain during polishing.
(C) Since the base layer having high affinity is provided on both the transparent conductive film and the hard coat, the transparent conductive film is difficult to peel off during polishing.
(D) Since polishing is performed using a polishing tape coated with fine particles of a hard substance, it is easy to obtain a polishing effect.
(E) Since the shape of the fine particles is spherical, polishing marks hardly remain.
(F) As a method of pressing the surface of the polishing tape against the surface of the transparent conductive film, a method of blowing a necessary and sufficient flow rate of air onto the back surface of the polishing tape and bringing it into contact with each other makes it difficult to leave polishing marks.

  According to the present invention, there is provided a method for smoothing the surface of a transparent conductive film without changing the existing transparent conductive film forming apparatus and the transparent conductive film forming process, and there is no spike-like protrusion on the surface. A transparent conductive film having excellent surface smoothness can be provided.

Hereinafter, embodiments of the present invention will be described in detail.
In FIG. 1, the cross-sectional schematic diagram of the laminated constitution of the transparent conductive film obtained by one Embodiment of this invention is shown. A base layer 3 and a transparent conductive film 4 are laminated on the surface of the transparent substrate film 1 via a hard coat layer 2. In addition to the effect of improving the adhesion of the transparent conductive film, the base layer 3 also has an effect of preventing water molecules from the base film side from diffusing to the transparent conductive film side.

  By providing the hard coat layer 2 in the present invention, the transparent conductive film is prevented from being damaged by polishing.

[Transparent substrate film]
The transparent substrate film used in the present invention is formed from a polymer. Examples of the polymer include polyester (for example, polyethylene terephthalate (PET), polyethylene naphthalate), poly (meth) acryl (for example, polymethyl methacrylate (PMMA)), polycarbonate (PC), polystyrene, polyvinyl alcohol, polyvinyl chloride, Examples thereof include polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyurethane, triacetate, and cellophane. Among these, polyester, polycarbonate, and polymethacrylate are preferable, and polyester is particularly preferable. As the polyester, polyethylene terephthalate is particularly preferable.

  The transparent substrate film may be an unstretched film or a stretched film depending on the type of polymer. For example, a biaxially stretched film is usually used for a polyester film, particularly a polyethylene terephthalate film, and an unstretched film is usually used for a polycarbonate film, a triacetate film, and a cellophane film.

  The thickness of the transparent substrate film is appropriately determined depending on the use of the antireflection film, and is preferably 20 to 500 μm. The transparent base film may be any film that transmits light, but a film having an average visible light transmittance of, for example, 50% or more, preferably 80% or more may be used.

[Hard coat layer]
In the present invention, the hard coat layer preferably forms a layer having transparency and appropriate hardness. The forming material is not particularly limited, and for example, a curable resin or a thermosetting resin by ionizing radiation or ultraviolet irradiation can be used. In particular, an ultraviolet irradiation curable acrylic or organic silicon resin or a thermosetting polysiloxane resin is suitable. Known resins can be used for these resins. More preferably, the hard coat layer has a refractive index equivalent to or close to that of the transparent substrate film. However, when the film thickness is 3 μm or more, there is no problem even if the refractive index is different.

  In forming the hard coat layer, there is no limitation on the coating method, but it is preferable to form the hard coat layer smoothly and uniformly.

In this hard coat layer, transparent inorganic fine particles having an average particle diameter of 0.01 μm to 1 μm may be mixed and dispersed. Thereby, the crosslinking shrinkage rate as a film | membrane can be improved and the flatness of a coating film can be improved. The inorganic fine particles can enhance the adhesion at the contact portion between the hard coat layer and the undercoat layer. As the inorganic fine particles, those having an affinity for the transparent conductive film are preferable, and SiO ₂ particles, TiO ₂ particles, ZrO ₂ particles, and Al ₂ O ₃ particles are preferable.

[Underlayer]
The underlayer of the present invention is preferably made of one or more substances selected from the group consisting of SiO ₂ , Si ₃ N ₄ and Al ₂ O ₃ . It may be a mixture of these substances. Particularly preferred is a mixture of SiO ₂ and Si ₃ N ₄ (SiO ₂ —Si ₃ N ₄ system). These substances or mixtures have a high affinity with the inorganic fine particles preferably contained in the hard coat layer and also have a high affinity with the conductive oxide forming the transparent conductive film. Can be produced.

The SiO ₂ —Si ₃ N ₄ -based thin film is more preferably used because it also has a moisture-proof effect that prevents water molecules from diffusing from the base film side to the transparent conductive film side (Miyadera et al., Organic EL Display technology December issue p65 (2001)).

  The underlayer is preferably a thin film having a thickness of 5 to 100 nm, and is most preferably formed by a sputtering method, but is not limited to this forming method, and is not limited to an ion plating method, a vacuum evaporation method, or a CVD method. The method can also be used.

The transparent conductive film of the present invention is selected from the group consisting of In ₂ O ₃ , ITO, SnO ₂ , Sb-doped SnO ₂ , F-doped SnO ₂ , ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO. It is preferable to consist of at least one kind of oxide. Among these, ITO is particularly preferable because it can achieve the lowest resistance and can easily form a pattern by wet etching.

[Transparent conductive film]
The transparent conductive film was selected from the group consisting of In ₂ O ₃ , Sn-doped In ₂ O ₃ , SnO ₂ , Sb-doped SnO ₂ , F-doped SnO ₂ , ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO. It is preferable to consist of at least one substance.

  The transparent conductive film is most preferably formed by a sputtering method, but is not limited to this forming method, and an ion plating method, a vacuum evaporation method, or a CVD method can also be used. The state of the transparent conductive film may be crystalline or amorphous, or a mixture of crystal and amorphous.

[Abrasive tape]
The fine particles coated on the polishing tape used in the present invention are made of at least one substance selected from the group consisting of Al ₂ O ₃ , CeO ₂ , Cr ₂ O ₃ , Fe ₂ O ₃ , SiO ₂ and SiC. This may consist of a mixture. Since these fine particles have a very high hardness, it is easy to obtain a polishing effect. While these fine particles are easy to obtain a polishing effect, they have very high hardness and may cause polishing marks depending on the shape of the particles. For this reason, the shape of the fine particles is preferably spherical. When the shape of the fine particles is an angular shape, the possibility that polishing marks remain after polishing becomes very high.

  The fine particles preferably have a particle size of 0.1 to 1 μm. If the particle size is smaller than 0.1 μm, the transparent conductive film cannot be sufficiently flattened by polishing, and if it is larger than 1 μm, the effect of roughening the surface is greater than the effect of flattening.

  As described above, the shape of the fine particles to be coated is preferably spherical, but fine particles having a corner shape can also be used. In this case, the base film used is made of a cushioning material. By using a base film having a cushioning property, it is possible to avoid polishing marks remaining after polishing. Polyurethane is suitable for the material of the cushioning base film.

In the surface smoothing method of the present invention, the surface coated with the fine particles of the polishing tape (hereinafter referred to as the coating surface) is brought into contact with the transparent conductive film surface, and air is blown onto the opposite surface (hereinafter referred to as the back surface). Polishing while applying pressing force. The flow rate of air to be blown is preferably in the range of 10 liters per minute to 500 liters per minute. If the flow rate is less than 10 liters per minute, the transparent conductive film surface cannot be flattened by polishing, and if the flow rate is greater than 500 liters per minute, polishing marks remain on the transparent conductive film during polishing. Probability is high. Further, in the drum type polishing method proposed in Japanese Patent Laid-Open No. 2002-086348, a polishing tape is supported by a cylindrical drum, and the roll is rotated and the tape is fed to apply pressure and polishing. When a soft polymer base material is used as in the present invention, the pressing load becomes strong, so that a polishing mark easily enters the film, which is not suitable for the polishing method of the present invention. Furthermore, in the present invention, when the surface of the transparent conductive film is polished and flattened with a polishing tape, it is not necessary to use a polishing liquid, and it is preferable to polish without using a polishing liquid. This is because the use of a polishing liquid during polishing leads to deterioration of characteristics when used as an electrode of a thin film transistor due to the influence of a residue of the polishing liquid.
In addition, there is no restriction | limiting in particular about the width | variety of an abrasive tape, What is necessary is just to match | combine with the magnitude | size of the surface to grind | polish.

Hereinafter, the present invention will be described more specifically with reference to examples.
In addition, the characteristic of the transparent conductive film was evaluated by the following method.
(1) Surface roughness The surface roughness was measured before and after smoothing by polishing. The surface of the transparent conductive film formed on the transparent polymer substrate provided with the hard coat layer via the underlayer was observed with an AFM (Atomic Force Microscope, Digital Instruments, Dimension3100), and the resulting AFM image was uneven. Was measured, and centrality average roughness Ra, 10-point average roughness Rz and maximum roughness Rmax were calculated.
(2) Surface resistance The surface resistance was measured before and after smoothing by polishing. The surface resistance of the surface of the transparent conductive film formed on the transparent polymer base material provided with the hard coat layer via the underlayer was measured with a four-probe surface resistance meter (Mitsubishi Chemical Loresta MP).
(3) Polishing marks Whether the polishing marks remain by observing the surface of the transparent conductive film formed on the transparent polymer base material provided with the hard coat layer via the underlayer with a reflection optical microscope after smoothing by polishing. I evaluated it. Evaluation was as follows: ○: Polishing traces, ×: No polishing traces.

[Example 1]
A transparent conductive film was produced in which the transparent conductive film was made of ITO. Using a biaxially oriented PET film (OLW-175 μm, manufactured by Teijin DuPont Film) as a transparent polymer film, a UV curable hard coat agent (JSR Desolite Z7501) was applied on one side by microgravure coating and UV cured. To form a hard coat layer. At this time, the thickness of the hard coat layer was 5 μm.

Next, an SiO ₂ film was formed as an underlayer on the hard coat layer by rf magnetron sputtering. It was formed while applying an electric power of 1 kW to the SiO ₂ target and introducing Ar gas into the vacuum chamber. At that time, the thickness of the SiO ₂ film was 20 nm.

Further, a transparent conductive film made of ITO was formed on the SiO ₂ film by a dc magnetron sputtering method. The ITO film was formed by applying a power of 1 kW to an ITO target containing 10% by weight of SnO ₂ and introducing a mixed gas in which 1% by volume of O ₂ gas was added to Ar gas into the vacuum chamber. At this time, the thickness of the ITO film was 175 nm. The surface resistance of the transparent conductive film thus produced was 36Ω / □, and Ra, Rz, and Rmax were 1.7 nm, 14 nm, and 22 nm, respectively.

This transparent conductive film was fixed to the polishing object support base 11 of the apparatus shown in FIG. 2, and the transparent conductive film surface was polished. As the polishing tape, AWA10000-25 (abrasive tape coated with 0.5 μm Al ₂ O ₃ particles) manufactured by Nihon Micro Coating is used, and the tape feed speed is constant at 200 mm / min. Polishing was performed while vibrating at a speed of 60 m / min. The air flow rate for bringing the transparent conductive film surface into contact with the coating surface of the polishing tape was 50 liters per minute.

  The transparent conductive film thus obtained by polishing had a surface resistance of 33Ω / □, and Ra, Rz, and Rmax were 0.7 nm, 4.5 nm, and 8.2 nm, respectively. Ra, Rz, and Rmax after polishing were less than 50% before polishing, and the smoothing effect could be clearly confirmed.

  The surface resistance slightly decreased after polishing. Since the surface of the transparent conductive film after polishing is very smooth, the contact area between the probe of the four-probe surface resistance meter and the surface of the transparent conductive film is considered to be slightly larger than before polishing ( 4a, b).

[Example 2]
The same operation as in Example 1 was conducted except that AWA-8000-25 (abrasive tape coated with 1 μm Al ₂ O ₃ particles) was used as the abrasive tape. Polishing marks were not observed and the evaluation was good. Ra, Rz, and Rmax after polishing were 0.8 nm, 5.1 nm, and 7.2 nm, respectively, and a flattening effect by polishing was clearly seen. The surface resistance after polishing was 34Ω / □.

[Example 3]
The same operation as in Example 1 was performed except that AWA-15000-25 (abrasive tape coated with 0.3 μm Al ₂ O ₃ particles) was used as the polishing tape. Polishing marks were not observed and the evaluation was good. Ra, Rz, and Rmax after polishing were 0.7 nm, 8.6 nm, and 9.1 nm, respectively, and a flattening effect by polishing was clearly seen. The surface resistance after polishing was 33Ω / □.

[Example 4]
This was carried out in the same manner as in Example 1 except that the air flow rate was 80 liters / min. Polishing marks were not observed and the evaluation was good. Ra, Rz, and Rmax after polishing were 0.6 nm, 4.9 nm, and 6.9 nm, respectively, and a flattening effect by polishing was clearly observed. The surface resistance after polishing was 35Ω / □.

[Example 5]
The same operation as in Example 2 was performed except that the air flow rate was 80 liters / min. Polishing marks were not observed and the evaluation was good. Ra, Rz, and Rmax after polishing were 0.8 nm, 7.1 nm, and 9.0 nm, respectively, and a flattening effect by polishing was clearly observed. The surface resistance after polishing was 34Ω / □.

[Example 6]
This was carried out in the same manner as in Example 3 except that the air flow rate was 80 liters / min. Polishing marks were not observed and the evaluation was good. Ra, Rz, and Rmax after polishing were 0.7 nm, 8.3 nm, and 8.8 nm, respectively, and a flattening effect by polishing was clearly observed. The surface resistance after polishing was 33Ω / □.

[Comparative Example 1]
It implemented like Example 1 except not providing a hard-coat layer in PET film. Polishing marks were observed and the evaluation was x. Ra, Rz, and Rmax after polishing of portions where polishing marks cannot be visually observed were 2.4 nm, 18 nm, and 25 nm, respectively. The surface resistance after polishing was 78Ω / □, and it was confirmed that the surface resistance was increased by polishing marks.

[Comparative Example 2]
This was carried out in the same manner as in Example 1 except that no underlayer was provided. Polishing marks were observed and the evaluation was x. Ra, Rz, and Rmax after polishing at portions where polishing marks cannot be visually observed were 2.1 nm, 15 nm, and 24 nm, respectively. The surface resistance after polishing was 84 Ω / □, and it was confirmed that the surface resistance was increased by polishing marks.

[Comparative Example 3]
It implemented like Example 1 except not providing both a hard-coat layer and a base layer. Polishing marks were observed and the evaluation was x. Ra, Rz, and Rmax after polishing of portions where polishing marks cannot be visually observed were 4.2 nm, 21 nm, and 35 nm, respectively. The surface resistance after polishing was 10 ³ Ω / □, and it was confirmed that the surface resistance was increased by polishing marks.

[Comparative Example 4]
This was carried out in the same manner as in Example 1 except that the air flow rate was 5 liters / min. Polishing marks were not observed and the evaluation was good. Ra, Rz, and Rmax after polishing were 1.6 nm, 16 nm, and 21 nm, respectively, and no planarization effect by polishing was observed. The surface resistance after polishing was 36Ω / □, and no change was observed.

[Comparative Example 5]
This was carried out in the same manner as in Example 2 except that the air flow rate was 5 liters / min. Polishing marks were observed and the evaluation was x. Ra, Rz, and Rmax after polishing at portions where polishing marks cannot be visually observed were 1.8 nm, 15 nm, and 24 nm, respectively. The surface resistance after polishing was 36 Ω / □, and it was confirmed that the surface resistance was increased by polishing marks.

[Comparative Example 6]
This was carried out in the same manner as in Example 3 except that the air flow rate was 5 liters / min. Polishing marks were observed and the evaluation was x. Ra, Rz, and Rmax after polishing at portions where polishing marks cannot be visually observed were 1.7 nm, 13 nm, and 20 nm, respectively. The surface resistance after polishing was 36 Ω / □, and it was confirmed that the surface resistance was increased by polishing marks.

[Comparative Example 7]
The same operation as in Example 1 was performed except that GC-10000-25 (abrasive tape coated with 0.5 μm SiC particles) manufactured by Nippon Micro Coating was used as the polishing tape. Polishing marks were observed and the evaluation was x. Ra, Rz, and Rmax after polishing of the portion where the polishing marks cannot be visually observed were 6.3 nm, 24 nm, and 36 nm, respectively. The surface resistance after polishing was 133 Ω / □, and it was confirmed that the surface resistance was increased by polishing marks.
The evaluation results are summarized in Table 1.

  If the transparent conductive film of this invention is used for the transparent electrode of an organic EL display, a display without a dark spot can be manufactured. Moreover, if a transparent conductive film is used as a transparent electrode of a touch panel, a panel with stable switching characteristics can be manufactured.

The structural example of the transparent conductive film of this invention. An example of the transparent conductive film surface polishing apparatus of this invention. An example of a roll contact type surface polishing apparatus. The contact state between the surface of the transparent conductive film before smoothing and the probe of the surface resistance measuring instrument. The contact state of the surface of the transparent conductive film after smoothing and the probe of the surface resistance measuring instrument.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base film 2 Hard coat layer 3 Underlayer 4 Transparent conductive film 5 Take-up spool 6 Supply spool 7 Polishing tape feed direction 8 Polishing tape 9 Polishing target 10 Support stand moving direction 11 Polishing target support stand 12 Air nozzle 13 Air flow direction 14 Contact roll 15 Resistance meter probe tip 16 Transparent conductive film surface 17 before smoothing Transparent conductive film surface after smoothing

Claims (5)

  A transparent base film is provided with a hard coat layer, a transparent conductive film is provided on the hard coat layer via an underlayer, and the surface of the transparent conductive film has a center line average surface roughness Ra of 1 nm or less and an average of 10 points. A method for producing a transparent conductive film, characterized in that a transparent conductive film having a flat surface is obtained by polishing the roughness Rz to 10 nm or less and the maximum height Rmax to 10 nm or less. The polishing of the surface of the transparent conductive film has a particle size of 0.1 to 10 consisting of at least one substance selected from the group consisting of Al ₂ O ₃ , CeO ₂ , Cr ₂ O ₃ , Fe ₂ O ₃ , SiO ₂ and SiC. Performed with a polishing tape having a center line average roughness Ra of 0.03 to 1.00 μm, a 10-point average roughness Rz of 0.8 to 4.0 μm, and a maximum height Rmax of 1 to 5 μm. The manufacturing method of the transparent conductive film of Claim 1.   The surface coated with the fine particles of the polishing tape is placed on the surface of the transparent conductive film of the transparent conductive film, and air is blown from the opposite surface of the polishing tape at a flow rate of 10 to 500 liters / min. The method for producing a transparent conductive film according to claim 1, wherein the surface coated with is contacted with the surface of the transparent conductive film of the transparent conductive film and the surface of the transparent conductive film is polished. A method for planarizing a surface of a transparent conductive film provided on a transparent base film provided with a hard coat layer via an underlayer, wherein the surface of the transparent conductive film is formed of Al ₂ O ₃ , CeO ₂ , Cr ₂ O _{3, Fe 2 O 3, SiO} 2 and at least one center line average roughness of the fine particle size 0.1~1μm made of a material coated on the tape base material selected from the group consisting of SiC Ra0.03～1 The center line average surface roughness Ra of the surface of the transparent conductive film is 1 nm or less and the 10 point average roughness Rz by a polishing tape having a 0.000 μm, 10 point average roughness Rz 0.8 to 4.0 μm and a maximum height Rmax 1 to 5 μm. Is polished to a thickness of 10 nm or less and a maximum height Rmax of 10 nm or less.   The transparent conductive film obtained by the manufacturing method of Claim 1.

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