KR101550091B1 - Transparent conductive film with low surface resistance and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a transparent conductive film exhibiting a low surface resistance, and more particularly, to a transparent conductive film having a conductive layer containing a p-type oxide layer and an n-type oxide layer, .
The transparent conductive film of the present invention can secure a low surface resistance of less than 150 Ω / square without adding a metal material that lowers the transmittance, can utilize the existing process without a separate sputtering facility, Can be prepared.

Description

TECHNICAL FIELD [0001] The present invention relates to a transparent conductive film having a low surface resistance and a method of manufacturing the same. [0002]

The present invention relates to a transparent conductive film exhibiting a low surface resistance, and more particularly, to a transparent conductive film having a conductive layer containing a p-type oxide layer and an n-type oxide layer, .

Transparent electrode film is one of the most important parts in manufacturing touch panel. The most widely used transparent electrode film to date is indium tin oxide (ITO) film having a total light transmittance of 85% or more and a surface resistance of 400 Ω / square or less.

In general, a transparent electrode film is used as a base film in which a primer coating treatment and a hard coating treatment are applied to a transparent polymer film so as to have surface flatness and heat resistance.

On this base film, a transparent undercoat layer was formed by wet coating or vacuum stuttering method, and then a transparent conductive layer such as ITO was formed by a sputtering method.

However, in the case of a touch panel having an area of about 4 inches, there is no problem in driving even with a transparent electrode film having the surface resistance. However, since a touch panel of a large-sized display with 7 to 10 inches or more has a long sensing distance, There is a demand for a conductive film having a low resistance that can efficiently detect a minute constant current in order to minimize the leakage current. ITO (Indium Tin Oxide) glass can easily heat the substrate during ITO thin film sputtering, so it can easily lower the surface resistance and ensure reliability by crystallization by heat. However, since glass is used as a substrate, it is difficult to handle, and there is a problem that it breaks well during hole machining and side chamfering. In the case of ITO sputtering, the chemical strengthening property disappears under the heating condition and sputtering should be performed at a room temperature similar to a plastic or film substrate there is a problem.

In order to solve this problem and to realize a low resistance on the film, an attempt to replace the ITO film by applying a sandwich structure in which a metal thin film is inserted between two ITO layers or a wet coating solution containing a metal sol or a metal component there was. In this case, although the electric characteristics of the transparent electrode film can be improved, the transmittance of the transparent electrode film is not more than 85% in terms of optical characteristics, and reflectance and haze are high.

Korean Patent Laid-Open No. 2005-33439 discloses an antireflection film in which a high refractive index layer, a low refractive index layer and a conductive layer are laminated, but does not consider deformation in a conductive layer which can lower the resistance.

In particular, a capacitive touch panel requires a highly transparent transparent conductive film which can overcome resolution, contrast ratio, and color sensitivity. However, there is no alternative but an ITO film, and development of a transparent conductive film having low resistance is required It is true.

Accordingly, the present inventors have made efforts to develop a transparent conductive film which can exhibit low surface resistance without adding a separate metal material, and as a result, the conductive layer contains a p-type oxide layer and a n-type oxide layer made of a specific oxide , It is possible to achieve a low surface resistance of not more than 150? / Square. Thus, the present invention has been completed.

Accordingly, an object of the present invention is to provide a transparent conductive film which can maintain a low surface resistance by forming a conductive layer including a p-type oxide layer and an n-type oxide layer, and a method for producing the same.

In order to achieve the above object, the transparent conductive film of the present invention comprises a transparent film; An undercoat layer formed on the transparent film; And a conductive layer formed on the undercoat layer, wherein the conductive layer includes a p-type oxide layer and an n-type oxide layer.

According to another aspect of the present invention, there is provided a method of fabricating a transparent conductive film, comprising: forming an undercoat layer on a transparent film; And forming a p-type oxide layer and an n-type oxide layer on the undercoat layer, wherein the p-type oxide layer and the n-type oxide layer are formed by a sputtering method.

The transparent conductive film of the present invention can secure a low surface resistance of less than 150 Ω / square without adding a metal material that lowers the transmittance, can utilize the existing process without a separate sputtering facility, Can be prepared.

Therefore, it is expected that the transparent conductive film of the present invention can minimize the signal error and improve the response speed in the touch panel of the large area display.

1 is a cross-sectional view of a transparent conductive film according to an embodiment of the present invention.
2 is a cross-sectional view of a transparent conductive film according to another embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Hereinafter, a transparent conductive film according to an embodiment of the present invention and a method of manufacturing the same will be described in detail.

Transparent conductive film

1 is a schematic cross-sectional view of a transparent conductive film according to an embodiment of the present invention. The transparent conductive film includes a transparent film 110, an undercoat layer 120, and a conductive layer 130, 131) and an n-type oxide layer (132).

The transparent film 110 may be a film having excellent transparency and strength. As the material of the transparent film 110, it is possible to show PET (polyethylene terephthalate), PEN (polyethylenenaphthalate), PES (polyethersulfone), PC (poly carbonate), PP (polypropylene), norbornene resin, May be used alone or in combination of two or more. In addition, the transparent film 110 may be in the form of a single film or a laminated film.

The undercoat layer 120 serves to improve the insulating property and transmittance between the transparent film and the conductive layer, and may be formed of silicon oxide (SiO ₂ ) having a refractive index of about 1.4.

The undercoat layer 120 is preferably formed to a thickness of 10 to 100 nm. If the thickness of the undercoat layer 120 is more than 100 nm, the film stress becomes severe, cracks may occur, optical properties may be deteriorated, and if the undercoat layer 120 is formed thinner than 10 nm, there is a problem in transmittance and visibility.

The next conductive layer 130 includes a p-type oxide layer 131 and an n-type oxide layer 132. In the present invention, when a multilayer thin film is formed of a p-type oxide and an n-type oxide, the carrier concentration of the n-type oxide layer can be increased by supplying holes from the p-type oxide, and a transparent conductive film having low surface resistance can be realized. The order of laminating the p-type oxide layer and the n-type oxide layer is not limited, but it is advantageous to form an n-type oxide layer on the p-type oxide layer. The p-type oxide layer, the n-type oxide layer, the p-type oxide layer, the n-type oxide layer, the p-type oxide layer and the n- As shown in FIG.

The p-type oxide layer may include at least one oxide selected from CuGaO ₃ , SrCu ₂ O ₂ , CuAlO ₂ , CuGaO _{2 and} N-doped ZnO, and preferably includes CuGaO ₃ . On the other hand, the p-type oxide layer may be doped with a p-type dopant, and magnesium (Mg) may be used as the p-type dopant.

The n-type oxide layer may include at least one oxide selected from indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium zinc oxide (IZO) and indium tin zinc oxide It is better to include ITO. The n-type oxide layer may further be doped with an n-type dopant, and the n-type dopant may be silicon (Si), germanium (Ge), tin (Sn), or the like.

The thicknesses of the n-type oxide layer and the p-type oxide layer are not particularly limited, but they are preferably formed to a thickness of 1 to 40 nm, more preferably 10 to 30 nm. In particular, when the thickness of each of the oxide layers exceeds 40 nm, the transmittance is largely lowered, thereby causing a problem in optical characteristics.

2 is a schematic cross-sectional view of a transparent conductive film according to another embodiment of the present invention. The transparent conductive film includes a transparent film 110, an undercoat layer 120, and a p-type oxide layer (not shown) 131, an n-type oxide layer 132, and a hard coating layer 140.

2, since the transparent film 110, the undercoat layer 120, and the conductive layer 130 are the same as those shown in FIG. 1, a detailed description thereof will be omitted.

In FIG. 2, a hard coating layer 140 is further formed on the upper and lower portions of the transparent film 110.

The hard coating layer 140 serves to improve the surface hardness and can be used without limitation as long as it is used for forming a hard coating such as an acrylic compound.

The hard coating layer 140 may be formed on both sides of the transparent film 110 as shown in FIG. 2, but may be formed only on one side of the transparent film 110.

The transparent conductive film of the present invention can be realized with a surface resistance of the conductive layer of 150 Ω / square or less and a low resistance of 100 Ω / square.

Method for producing transparent conductive film

In the method for producing a transparent conductive film of the present invention,

Forming an undercoat layer on the transparent film; and forming a p-type oxide layer and an n-type oxide layer on the undercoat layer,

And the p-type oxide layer and the n-type oxide layer are formed by a sputtering method.

In forming the undercoat layer, a sputtering method or an ion plating method can be used. More specifically, the undercoat layer can be formed by a DC power reactive sputtering method using a SiO ₂ target.

As described above, the undercoat layer is preferably formed to a thickness of 10 to 100 nm.

The p-type oxide layer and the n-type oxide layer are formed by a sputtering method, and more specifically, they may be formed by a DC power reactive sputtering method. As described above, each of the oxide layers is preferably formed to a thickness of 1 to 40 nm, more preferably 10 to 30 nm. Although the order of stacking the p-type oxide layer and the n-type oxide layer is not limited, it is advantageous to form an n-type oxide layer on the p-type oxide layer. The p-type oxide layer, the n-type oxide layer, the p-type oxide layer, the n-type oxide layer, the p-type oxide layer and the n- As shown in FIG.

3, a hard coating layer (140 in FIG. 2) may be further formed on one side or both sides of the transparent film 110 with an acrylic compound or the like in order to improve the surface hardness.

The hard coating layer 140 may be formed on one side or both sides of the transparent film 110 on which the undercoat layer is not formed and may be formed only on the lower side of the transparent film 110 in the state where the undercoat layer is formed.

Hereinafter, the transparent conductive film of the present invention will be described in detail with reference to preferred embodiments and comparative examples of the present invention.

The following examples and comparative examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example  One

A silicon oxide thin film was deposited to a thickness of 20 nm on a surface of a 125 탆 thick PET film having acrylic hard coatings on both sides by reactive sputtering to form an undercoat layer. Then, an oxide layer was formed by sputtering in the order of a CuGaO ₃ layer and an ITO layer each having a thickness of 20 nm to prepare a transparent conductive film.

Example  2

A transparent conductive film was produced in the same manner as in Example 1, except that an oxide layer was formed on the undercoat layer in the order of 20 nm thick ITO layer and CuGaO ₃ layer by sputtering.

Example  3

A transparent conductive film was prepared in the same manner as in Example 1, except that an oxide layer was formed on the undercoat layer in the order of 20 nm thick CuGaO ₃ layer, ITO layer and CuGaO ₃ layer by sputtering.

Example  4

A transparent conductive film was produced in the same manner as in Example 1, except that an oxide layer was formed on the undercoat layer in the order of 20 nm thick ITO layer, CuGaO ₃ ITO layer and CuGaO ₃ layer by sputtering.

Comparative Example

A silicon oxide thin film was formed on one surface of the same hard-coated PET film as in Example 1 to a thickness of 20 nm, heat-treated thereon, and only a 20 nm thick ITO layer was formed by sputtering to form a transparent conductive film.

Evaluation (comparison of surface resistance)

In order to measure the surface resistivity of the transparent conductive films of the examples and comparative examples, the surface resistance was measured by a thinning method using a low resistivity meter manufactured by Mitsubishi Chemical.

The measurement results are shown in Table 1 below.

Transparent conductive film Surface resistance (Ω / square) Example 1 125 Example 2 156 Example 3 149 Example 4 168 Comparative Example 270

As shown in Table 1, the transparent conductive film of the present invention can significantly reduce the surface resistance compared with the transparent conductive film of the comparative example in which the conductive layer is formed only of ITO, thereby minimizing the occurrence of malfunction or noise in a touch panel of a large- can do.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. . Accordingly, the true scope of the present invention should be determined by the following claims.

110: Transparent film 120: Undercoat layer
130: conductive layer 131: p-type oxide layer
132: n-type oxide layer 140: hard coat layer

Claims (11)

Transparent film;
An undercoat layer formed of silicon oxide (SiO ₂₎ on the transparent film; And
And a conductive layer formed on the undercoat layer,
Wherein the conductive layer comprises a p-type oxide layer including CuGaO ₃ and an n-type oxide layer on the p-type oxide layer, and the p -Type oxide layer and an n-type oxide layer are formed to a thickness of 20 to 40 nm by a sputtering method using a SiO ₂ target, the p-type oxide layer contains Mg as a p-type dopant, and the surface resistance of the conductive layer is 100 To 150 < RTI ID = 0.0 > OMEGA / square < / RTI &
The method according to claim 1,
Wherein the p-type oxide layer further comprises at least one oxide selected from SrCu ₂ O ₂ , CuAlO ₂ and CuGaO ₂ .
The method according to claim 1,
Wherein the n-type oxide layer comprises at least one oxide selected from the group consisting of ITO (Indium Tin Oxide), FTO (Fluorine-doped Tin Oxide), IZO (Indium Zinc Oxide) and ITZO (Indium Tin Zinc Oxide) Conductive film.
delete delete The method according to claim 1,
The transparent film is a single or laminated film made of at least one of PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PES (polyethersulfone), PC (poly carbonate), PP By weight.
delete delete Of silicon oxide (SiO ₂₎ on a transparent film to form the undercoat layer; And
Forming a p-type oxide layer containing CuGaO ₃ on the undercoat layer and an n-type oxide layer on the p-type oxide layer to form a conductive layer having a surface resistance of 100 to 150 Ω / square or less, A hard coating layer is formed on one side or both sides of a transparent film by an acrylic compound, and the p-type oxide layer and the n-type oxide layer are formed to a thickness of 20 to 40 nm by a sputtering method using a SiO ₂ target, Wherein the p-type dopant contains Mg as the p-type dopant.
10. The method of claim 9,
Wherein the p-type oxide layer and the n-type oxide layer are formed by a DC power reactive sputtering method.
delete

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