WO2022020975A1

WO2022020975A1 - Bending-resistant transparent conductive composite film and manufacturing method therefor

Info

Publication number: WO2022020975A1
Application number: PCT/CN2020/000179
Authority: WO
Inventors: 张汉焱; 沈奕; 冯兆昌; 郑丹旭; 吕岳敏; 欧建平
Original assignee: 汕头超声显示器技术有限公司; 汕头超声显示器（二厂）有限公司; 汕头超声显示器有限公司
Priority date: 2020-05-25
Filing date: 2020-08-10
Publication date: 2022-02-03
Also published as: CN111681806A; CN111681806B

Abstract

Disclosed are a bending-resistant transparent conductive composite film and a manufacturing method therefor. The bending-resistant transparent conductive composite film comprises a transparent conductive film arranged on a flexible support film and a polymer layer. The transparent conductive film is a transparent conductive oxide thin film plated on the flexible support film; the transparent conductive film comprises a thin film substrate and a large number of hill-shaped protrusions uniformly distributed on the thin film substrate; and the polymer layer is arranged on the transparent conductive film and comprises a large number of polymer chains, and at least some of the polymer chains surround the hill-shaped protrusions to form hill-shaped protrusion binding structures. The transparent conductive composite film has good bending resistance, and can maintain good transparency, conductivity and uniformity.

Description

Bending-resistant transparent conductive composite film and manufacturing method thereof

technical field

The invention relates to a transparent conductive composite film, in particular to a bending-resistant transparent conductive composite film and a manufacturing method thereof.

Background technique

Transparent conductive films are generally used as transparent electrodes on touch displays (such as touch screens, displays). In recent years, with the development of bending or flexible electronic products, it is expected that the touch display can also be made flexible, and thus the transparent conductive film as its transparent electrode is required to have bending resistance.

The traditional transparent conductive films are mostly transparent conductive oxide films such as indium tin oxide (ITO) and zinc aluminum oxide (AZO). However, since it is a brittle metal oxide, it is easily broken when subjected to bending, resulting in the failure of the function of the film layer, and it is currently difficult to apply in flexible touch displays.

For this reason, some people propose to use non-transparent conductive oxide films such as metal mesh and nano-silver wire film as a bending-resistant transparent conductive film, which generally has good bending resistance. However, these non-transparent conductive oxide films The transparency, conductivity or uniformity of oxide films are generally poor, and when they are applied to touch displays, the performance of the touch displays is often degraded.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a bending-resistant transparent conductive composite film and a manufacturing method thereof. The transparent conductive composite film has good bending resistance and can also maintain good transparency, conductivity and uniformity.

In order to solve the above technical problems, the technical solutions adopted are as follows:

The bending-resistant transparent conductive composite film includes a transparent conductive film arranged on a flexible support film, the transparent conductive film is a transparent conductive oxide film plated on the flexible support film, and is characterized in that: it also includes a polymer layer; the The transparent conductive film includes a film base and a large number of mound-shaped protrusions evenly distributed on the film base; the polymer layer is arranged on the transparent conductive film, and the polymer layer includes a large number of polymer chains, and at least part of the polymer chains surround the The mound-shaped bulge forms the binding structure of the mound-shaped bulge.

In the above-mentioned transparent conductive composite film, a large number of mound-shaped protrusions are evenly distributed on the film substrate, and the mound-shaped protrusions are surrounded by a large number of polymer chains to form a confinement structure of the mound-shaped protrusions; using this structure makes the transparent conductive composite film. When bending under force, the confinement structure of the mound-shaped protrusions can play a supporting and tightening role, tightening the transparent conductive composite film, avoiding the rupture of the transparent conductive composite film, and effectively maintaining the conductivity of the transparent conductive composite film.

The flexible support film usually adopts glass sheet, plastic film, polyimide plastic film or colorless polyimide plastic film. The glass sheet is usually a sheet with a thickness of less than 0.2mm. The polyimide plastic film has good high temperature resistance (high temperature facilitates the film formation and crystallization of the transparent conductive film), and the colorless polyimide plastic film can ensure transparency. The transparent conductive film is a thin film made of indium tin oxide (ITO), zinc aluminum oxide (AZO), indium gallium zinc oxide (IGZO) or other transparent conductive oxides. The thickness of the transparent conductive film is 10-100 nm, and in a specific solution, the thickness of the transparent conductive film is 20-60 nm. The use of such a thickness of the transparent conductive film can reduce the internal stress of the film when it is subjected to bending under the condition of ensuring the conductive performance of the film.

In a preferred solution, when the mound-shaped protrusions are coated, the mound-shaped protrusions are naturally generated on the surface of the transparent conductive film through the control of coating parameters.

In a further preferred solution, the mound-shaped protrusions are the outwardly extending parts of the columnar crystals embedded in the film substrate. Specifically, a magnetron sputtering deposition process can be used to form the transparent conductive film, based on magnetron sputtering. The film formation mechanism of the sputtered island crystal growth makes the transparent conductive film a polycrystalline structure composed of columnar crystals, and the consistency of the growth rate of each columnar crystal is reduced by increasing the sputtering power, so that the final growth rate is higher. Some columnar crystals form hill-like protrusions on the surface of the transparent conductive film. The mound-shaped protrusion is the outward extension of the columnar crystal embedded in the film matrix, that is to say, the mound-shaped protrusion has a root embedded in the film matrix, and the combination with the film matrix is tighter. When the mound-shaped protrusions are bound by the polymer chains, the force of the polymer chains can be effectively transferred into the film matrix, which makes the transparent conductive composite film more tough.

In another preferred solution, the mound-shaped protrusions are formed by roughening a process after the transparent conductive film is formed.

In a further preferred solution, the mound-shaped protrusions are formed by etching the surface of the transparent conductive film with an etching solution after the transparent conductive film is fabricated. Since the crystallinity of different regions of the transparent conductive film (such as the center and edge of the crystal grains that constitute the polycrystalline film) is inconsistent, the etching speed is also inconsistent, and the position where the etching is slower (such as the center of the crystal grain) forms a mound-shaped protrusion. In other words, the mound-shaped protrusions formed by etching can also form a structure in which the roots are embedded in the film substrate. The above-mentioned etching solution can be diluted aqua regia or the like.

In a specific solution, the height of the mound-shaped protrusion is 20%-50% of the substrate of the transparent conductive film. The height of the mound-shaped protrusion can be controlled by process adjustment (such as coating power, etching time). The height of the mound-shaped protrusion is 20%-50% of the transparent conductive film substrate, so that the polymer chain can The protrusions form a restraining structure.

In a preferred solution, the polymer layer is a polymer coating, and the polymer layer is formed by polymerizing or cross-linking monomer molecules on the surface of the transparent conductive film. First, the polymer coating is made of materials with good elasticity and toughness (such as polyethylene, polypropylene, polyamide, polyimide, etc.), and the polymer coating generally contains a large number of polymer chains; When the polymer layer is used, the monomer molecules used to form the polymer chain can be placed on the surface of the transparent conductive film by means of evaporation, solution coating, etc., and then the polymerization reaction is initiated to form the polymer layer. The permeability is good, and it easily penetrates into the gaps between the mound-shaped protrusions, and then polymerization can effectively form a polymer chain that binds the mound-shaped protrusions.

In a further preferred solution, the polymer layer has a preset tensile stress. The polymer layer maintains a certain tension state between the mound-shaped protrusions, so that when the composite film is subjected to bending, the polymer layer can adapt to the bending change of the composite film more quickly, so as to maintain the toughness of the composite film during the bending process. Avoid cracking of the transparent conductive film.

In a further preferred solution, the polymer chain is formed by light-initiated polymerization or cross-linking reaction, and the light-initiated polymerization or cross-linking reaction can generally make the formed polymer chain in a tensioned state, and finally in the polymer layer. A preset tensile stress is formed. In a specific solution, the polymer layer is a polyacrylic acid film formed by photo-initiated polymerization or cross-linking reaction. Polyacrylic films are capable of forming significant tensile stress.

In a further preferred solution, in the formation process of the polymer layer, the polymer chain length of the polymer layer is increased by optimizing the components and/or the polymerization process, so that in the polymer layer, at least part of the polymer chain length is increased. The polymer chains together form a binding structure around two adjacent mound-like protrusions. Preferably, when the polymer chains together form a binding structure around two adjacent hill-shaped protrusions, the polymer chains together form an "8"-shaped binding structure around two adjacent hill-shaped projections. The above structure can bind the adjacent mound-shaped protrusions, improve the overall toughness of the composite film, and further increase its bending resistance. The thickness of the polymer layer only needs to be made equal to the height of the mound-shaped protrusions, so that the toughness and bending resistance of the transparent conductive composite film can be improved. In order to make it easier to manufacture, the polymer layer can also be made thicker, such as a thick coating of 1 μm to 10 μm, the bottom of which is in contact with the transparent conductive film also has the above-mentioned polymer chains surrounding the hill-shaped protrusions to form a bond. structure.

A manufacturing method of a bending-resistant transparent conductive composite film, characterized in that it comprises the following steps:

Step (1), disposing a transparent conductive oxide film on the flexible support film, and distributing a large number of mound-shaped protrusions on the surface of the transparent conductive oxide film;

In step (2), a polymer layer is arranged on the transparent conductive oxide film, and at least part of the polymer chain of the polymer layer is formed around the mound-shaped protrusion to form a binding structure.

In a preferred solution, in the above step (1), the mound-shaped protrusions are the outwardly extending parts of the columnar crystals embedded in the film substrate. Specifically, a magnetron sputtering deposition process can be used to form the transparent conductive Film, based on the film-forming mechanism of magnetron sputtering island crystal growth, the transparent conductive film is finally a polycrystalline structure composed of columnar crystals, and the consistency of the growth rate of each columnar crystal is reduced by increasing the sputtering power, so that the Finally, some columnar crystals with higher growth rate form hill-shaped protrusions on the surface of the transparent conductive film.

In a preferred solution, in the above step (1), the mound-shaped protrusions are formed by etching the surface of the transparent conductive film with an etching solution after the transparent conductive film is fabricated. The etching solution can be diluted aqua regia.

In a preferred solution, in the above step (2), the method for forming the polymer chain surrounding the mound-shaped protrusion is to use monomer molecules on the surface of the transparent conductive film by photo-induced polymerization or cross-linking reaction to form a polymer chain.

The beneficial effect of the present invention is that: a large number of mound-shaped protrusions are arranged on the surface of the transparent conductive oxide thin film of the transparent conductive film, and then a polymer layer is arranged on the transparent conductive film, so that the polymer chains surround the mound-shaped protrusions When the transparent conductive composite film is bent, the polymer chains bound on the mound-shaped protrusions can tighten the transparent conductive film and prevent it from cracking. The conductivity of the transparent conductive film is effectively maintained. Therefore, this transparent conductive composite film not only has good bending resistance, but also its conductive layer is a transparent conductive oxide film, which has the good transparency, conductivity and uniformity of a general transparent conductive oxide film.

Description of drawings

1 is a cross-sectional view of a transparent conductive composite film in Example 1 of the present invention;

2 is a schematic diagram of the transparent conductive film and the polymer layer of the transparent conductive composite film in Example 1 of the present invention.

detailed description

Below in conjunction with accompanying drawing and specific embodiment, the present invention is further described:

Example 1

The bending-resistant transparent conductive composite film shown in FIG. 1-2 includes a transparent conductive film 2 and a polymer layer 3 disposed on the flexible support film 1 , and the transparent conductive film 2 is a transparent conductive film plated on the flexible support film 1 . Conductive oxide film; the transparent conductive film 2 includes a film base 201 and a large number of mound-shaped protrusions 202 evenly distributed on the film base 201; the polymer layer 3 is arranged on the transparent conductive film 2, and the polymer layer 3 includes a large number of The polymer chains 301 , and part of the polymer chains 301 surround the mound-shaped protrusions 202 to form a binding structure of the mound-shaped protrusions 202 .

The thickness of the transparent conductive film 2 was 10 nm. The height of the hill-shaped protrusions 202 is 20% of the transparent conductive film substrate 201 . The polymer layer 3 is a polymer coating.

The specific manufacturing method of this bending-resistant transparent conductive composite film is as follows:

In step (1), a transparent conductive oxide film is arranged on the flexible support film 1, and a large number of mound-shaped protrusions 202 are distributed on the surface of the transparent conductive oxide film;

In step (2), a polymer layer 3 is arranged on the transparent conductive oxide film, and part of the polymer chains 301 of the polymer layer 3 surrounds the mound-shaped protrusion 202 to form a monocyclic binding structure 302; part of the polymer chains 301 surrounds together Two adjacent mound-shaped protrusions 202 form an encircling confinement structure 303 ; part of the polymer chains 301 jointly surround the two adjacent mound-shaped protrusions 202 to form an “8”-shaped confinement structure 304 .

In the above step (1), the mound-shaped protrusions 202 are the outwardly extending portions of the columnar crystals 203 embedded in the film substrate 201 , and the transparent conductive film 2 is formed by a magnetron sputtering deposition process. , based on the film-forming mechanism of the island crystal growth by magnetron sputtering, the transparent conductive film 2 is finally a polycrystalline structure composed of columnar crystals 203, and the consistency of the growth rate of each columnar crystal 203 is reduced by increasing the sputtering power , so that some columnar crystals 203 with a higher final growth rate form hill-shaped protrusions 202 on the surface of the transparent conductive film 2 .

In the above step (2), the method for forming the polymer chains 301 surrounding the mound-shaped protrusions 202 is to use monomer molecules to form polymer chains on the surface of the transparent conductive film 2 by light-induced polymerization or cross-linking reaction 301.

Example 2

In the case where other parts of this embodiment are the same as those of Embodiment 1, the difference is that the mound-shaped protrusions are formed by etching the surface of the transparent conductive film with an etchant after the transparent conductive film is fabricated. Since the crystallinity of different regions of the transparent conductive film (such as the center and edge of the crystal grains that constitute the polycrystalline film) is inconsistent, the etching speed is also inconsistent, and the position where the etching is slower (such as the center of the crystal grain) forms a mound-shaped protrusion, which The hill-like protrusions formed by etching can also form a structure in which the roots are embedded in the film substrate. The above-mentioned etching solution can be diluted aqua regia or the like.

Example 3

When other parts of this embodiment are the same as those of Embodiment 1, the difference is that the thickness of the transparent conductive film is 100 nm.

Example 4

When other parts of this embodiment are the same as those of Embodiment 1, the difference is that the height of the mound-shaped protrusion is 50% of the substrate of the transparent conductive film.

Claims

The bending-resistant transparent conductive composite film includes a transparent conductive film arranged on a flexible support film, the transparent conductive film is a transparent conductive oxide film plated on the flexible support film, and is characterized in that: it also includes a polymer layer; the The transparent conductive film includes a film base and a large number of mound-shaped protrusions evenly distributed on the film base; the polymer layer is arranged on the transparent conductive film, and the polymer layer includes a large number of polymer chains, and at least part of the polymer chains surround the The mound-shaped bulge forms the binding structure of the mound-shaped bulge.
The bending-resistant transparent conductive composite film according to claim 1, wherein the mound-shaped protrusions are naturally generated on the surface of the transparent conductive film by controlling coating parameters during coating.
The bending-resistant transparent conductive composite film according to claim 2, wherein the mound-shaped protrusions are the outwardly extending parts of the columnar crystals embedded in the film matrix, which can be deposited by magnetron sputtering. process to form the transparent conductive film, based on the film-forming mechanism of the magnetron sputtering island crystal growth, so that the transparent conductive film is finally a polycrystalline structure composed of columnar crystals, and by increasing the sputtering power, the columnar crystals are reduced. The consistency of the growth rate makes some columnar crystals with a higher final growth rate form hill-shaped protrusions on the surface of the transparent conductive film.
The bending-resistant transparent conductive composite film according to claim 1, wherein the mound-shaped protrusions are formed by roughening a process after the transparent conductive film is formed.
The bending-resistant transparent conductive composite film according to claim 4, wherein the mound-shaped protrusions are formed by etching the surface of the transparent conductive film with an etching solution after the transparent conductive film is fabricated.
The bending-resistant transparent conductive composite film according to claim 1, wherein the polymer layer is a polymer coating, and the polymer layer is formed by polymerizing or cross-linking monomer molecules on the surface of the transparent conductive film.
The bending-resistant transparent conductive composite film of claim 6, wherein the polymer layer has a predetermined tensile stress.
The bending-resistant transparent conductive composite film according to claim 7, wherein the polymer chain is formed by light-induced polymerization or cross-linking reaction, and the light-induced polymerization or cross-linking reaction generally can make the formed high polymer chain The molecular chain is in a state of tension, and finally a preset tensile stress is formed in the polymer layer.
The bending-resistant transparent conductive composite film according to claim 8, characterized in that: during the formation of the polymer layer, the polymer chains of the polymer layer are enlarged by optimizing the components and/or the polymerization process. The length is such that in the polymer layer, at least part of the polymer chains together form a binding structure around two adjacent hill-shaped protrusions.
The manufacturing method of a bending-resistant transparent conductive composite film is characterized by comprising the following steps:

Step (1), disposing a transparent conductive oxide film on the flexible support film, and distributing a large number of mound-shaped protrusions on the surface of the transparent conductive oxide film;

In step (2), a polymer layer is arranged on the transparent conductive oxide film, and at least part of the polymer chain of the polymer layer is formed around the mound-shaped protrusion to form a binding structure.