CN111446028A

CN111446028A - Transparent conductive film and touch screen

Info

Publication number: CN111446028A
Application number: CN202010349452.6A
Authority: CN
Inventors: 张玉春; 仲树栋
Original assignee: Beijing Zenithnano Technology Co Ltd
Current assignee: Beijing Zenithnano Technology Co Ltd
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2020-07-24

Abstract

The embodiment of the application discloses a transparent conductive film and a touch screen, wherein the transparent conductive film comprises a base material, at least two IM layers and a conductive layer which are sequentially stacked; the two IM layers sequentially comprise an organic material layer and an inorganic material layer which are arranged on the substrate; the conducting layer sequentially comprises a metal doping layer and a transparent conducting material layer which are arranged on the IM layer; the metal doped layer comprises metal and nitride metal and/or metal and oxide metal. The application changes the original metal into the metal doped layer, thereby improving the conductivity. The arrangement of the double IM layers reduces the overall reflectivity of the IM layer, so that the IM layer can be matched with the conductive layer with low reflectivity, and the chromatic aberration of the conductive film is reduced.

Description

Transparent conductive film and touch screen

Technical Field

The application relates to the field of optical films, in particular to a transparent conductive film and a touch screen.

Background

The transparent conductive film is a core element of many products such as touch screens, and it is a target pursued in the industry to improve the conductivity and reduce the thickness of the transparent conductive film. As shown in fig. 1, the structure of the transparent conductive film newly developed at present includes a substrate layer, and I M layers and a conductive layer sequentially disposed on the substrate layer, wherein the conductive layer is formed by sequentially stacking a transparent conductive material layer and a metal layer. By means of the principle of tunnel breakdown, the conducting layer structure improves the conductivity of the conducting film compared with the prior art.

In the above structure, the metal layer has a characteristic: when the thickness is thin, the film is formed into an island-shaped film structure, and the conductivity is poor due to the discontinuity. To ensure conductivity, the thickness must be ensured, and the thickness of a single metal layer is generally required to be more than 10 nm. A contradiction between the low thickness and the high conductivity of the transparent conductive film is created.

In addition, the AR antireflection effect is formed between the transparent conductive material layer and the metal layer in the above structure due to the high refractive index of the transparent conductive material layer and the low refractive index of the metal layer, so that the reflectance of the conductive layer is reduced, and the effect that the lower the resistance of the conductive layer is, the lower the reflectance is achieved. That is, the reflectivity of the conductive layer of the current transparent conductive film can be small. It is known that, in order to ensure that the chromatic aberration of the conductive film is small enough, it is better that the difference between the reflectances of the IM layer (INDEX mark) and the conductive layer is small, but the current reflectivity of the IM layer cannot be made lower, and therefore cannot be matched with the reflectivity of the conductive layer, and thus the chromatic aberration is large.

Therefore, how to improve the conductivity and reduce the color difference of the current conductive film under the condition of low thickness is a problem which is urgently needed to be solved at present.

Disclosure of Invention

The application provides a transparent conductive film and a touch screen to solve the above problems in the prior art.

The application provides the following scheme:

the transparent conductive film comprises a base material, at least two IM layers and a conductive layer which are sequentially stacked;

the two IM layers sequentially comprise an organic material layer and an inorganic material layer which are arranged on the substrate;

the conducting layer sequentially comprises a metal doping layer and a transparent conducting material layer which are arranged on the IM layer;

the metal doped layer is a doped layer of metal and nitride metal and/or metal and oxide metal.

Preferably, the atomic percentage of oxygen or nitrogen in the first metal doped layer and the first metal doped layer is 1.5 at% to 5.5 at%.

Preferably, the metal doped layer is a continuous film layer, and the thickness of the metal doped layer is less than 10 nm.

Preferably, the metal doped layer is formed by introducing a small amount of O2 and/or N2 during the metal target coating process.

Preferably, the organic material layer is disposed by coating, and the inorganic material layer is disposed by sputtering.

Preferably, the resistance value of the conductive layer is less than 100 ohms; the refractive index of the organic material layer is 1.6-1.7; the refractive index of the inorganic material layer is 1.4-1.6.

Preferably, the conductive layer has an equivalent refractive index of 1.4 to 1.5.

Preferably, the first and second liquid crystal materials are,

a first weather-resistant layer and/or a first anti-oxidation layer are/is arranged between the metal doping layer and the transparent conductive material layer;

and/or a second weather-resistant layer and/or a second antioxidant layer is/are arranged between the metal doped layer and the inorganic material layer.

Preferably, the first and second liquid crystal materials are,

the transparent conductive film comprises a hard coating layer, an antireflection layer, a substrate layer, an organic material layer, an inorganic material layer, a second weather-resistant layer, a second antioxidant layer, a metal doping layer, a first antioxidant layer, a first weather-resistant layer and a transparent conductive material layer which are sequentially stacked.

The application on the other hand also provides a touch screen, the touch screen comprises the transparent conductive film, and the conductive adhesive and the glass panel which are sequentially arranged on the transparent conductive film.

According to the specific embodiments provided herein, the present application discloses the following technical effects:

according to the technical scheme, the metal doping layer can have good conductivity even under the condition of low thickness of less than 10nm by utilizing the good continuous film layer characteristic of the metal doping layer in which metal and nitrogen oxide metal coexist, so that the conductivity under the condition of the same thickness is improved compared with a metal layer. Meanwhile, the overall reflectivity of the IM layer is reduced by arranging two IM layers, so that the I M layer can be matched with the low reflectivity of the conductive layer, and the overall chromatic aberration of the transparent conductive film is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a diagram of a low resistance transparent conductive film in the prior art;

fig. 2 to 4 are structural diagrams of the transparent conductive film provided in the embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments that can be derived from the embodiments given herein by a person of ordinary skill in the art are intended to be within the scope of the present disclosure.

The application aims to provide a transparent conductive film with a novel structure, a metal layer is replaced by a metal and nitrogen/oxide metal doped layer, and the conductivity of the conductive layer under the condition of low thickness is improved by utilizing the characteristic that the doped layer is still a continuous film under the condition of low thickness. The overall reflectivity of the IM layer is reduced by arranging the two IM layers, so that the IM layer can be matched with the low reflectivity of the conducting layer, and the overall chromatic aberration of the transparent conducting film is reduced.

As shown in fig. 2, a structure diagram of a transparent conductive film provided in the present application includes a substrate layer, a first IM layer, a second IM layer, and a conductive layer, which are sequentially stacked, where the conductive layer includes a metal doped layer and a transparent conductive material layer, which are sequentially stacked. The metal doped layer is a doped layer of metal and nitride metal and/or metal and oxide metal.

The doped layer in which metal and nitrogen/oxide metal coexist has a characteristic that even in the case of a thin thickness, for example, less than 10nm, it is a continuous film layer, and the conductivity is greatly improved compared with a pure metal layer of the same thickness. In an actual arrangement, the metal doped layer may be set to 10nm or less.

The metal doped layer can be formed by introducing a small amount of O2 and/or N2 during the metal target coating process, so that the metal and the oxidized/nitrided metal coexist. The metal is typically Ag, Cu, Al, Mo, Ag alloy, Cu alloy, Al alloy, Mo alloy, etc. The atomic percentage of oxygen or nitrogen atoms in the metal doped layer is 1.5at percent to 5.5at percent. The atomic percent of oxygen or nitrogen atoms can be controlled by controlling the amount of O2 and/or N2 introduced. In the preferred embodiment, the metal Ag is connected with O2, and the metal Cu is connected with N2.

In order to ensure the conductivity of the conductive film, the metal doped layer needs to adopt a continuous film layer structure, and preferably, the thickness of each layer of the metal doped layer is more than 10 nm. Wherein the material of the metal doped layer may preferably be silver.

In the structure shown in fig. 2, the first IM layer and the second IM layer are stacked, and the reflection light is cancelled by the interference effect by using the AR antireflection principle, thereby reducing the reflectance.

The first and second IM layers shown in fig. 2 are an organic material layer and an inorganic material layer, respectively, and the inorganic material layer is in contact with the first metal layer in consideration of not affecting the conductivity of the metal layer. Wherein the organic IM layer can achieve a 1-2% reflectivity subtraction effect. The inorganic IM layer can realize the antireflection effect with the reflectivity of 2-4 percent. The two are combined, so that the cost is low and the effect is better. The inorganic material layer is in contact with the first metal doped layer in consideration of not affecting the conductivity of the metal doped layer.

Wherein the organic material layer can be made of C \ H \ O resin with high refractive index of 1.6-1.7, wherein metal elements such as Si, Zr, Ti and the like are doped; the thickness can be set as desired, preferably 0.5-5 um.

The inorganic material layer may be a single layer or may be a plurality of matching layers having different refractive indices.

If the insulation sheet resistance is a single layer, a non-conductive metal material with an insulation sheet resistance of more than 10 x 8 Ω/□ can be used, for example: ti, In, Sn, InSn alloy (In doping weight percentage is 0-50 percent), SiAl alloy (Al doping weight percentage is 0-50 percent), and the thickness can be set according to the requirement, and is preferably 0.5-80 nm.

The inorganic material layer is formed by combining at least one layer of low refractive index material and at least one layer of high refractive index material, and the insulation sheet resistance of the inorganic material layer is more than 10 x 8 omega/□. Wherein the low refractive index material can be metal oxide with a refractive index of 1.2-1.7, non-metal oxide, sulfide, fluoride, carbide, such as SiO2, Al2O3, MgF, MgS, SiC, etc., and the thickness can be set to 10-500 nm; the high-refractive-index material can be metal oxide, nitride, sulfide with a refractive index of 1.8-2.4, or a dopant thereof (the doped material comprises one or more of Al, Ga, Zr, B, Y, Mo, Sn and the like), such as TiO2, SnO2, ZnO, Nb2O5, Ta2O5, Si3N4, ZnS, the dopant comprises AZO, GZO, YZO and the like, and the thickness can be set to be 2-200 nm.

In the actual manufacturing process, the first IM layer is preferably coated, and the second IM layer is preferably sputtered, which takes into account that although the sputtering method has better adhesion, the sputtered layer has color difference. The coating mode has general adhesive force but small color difference, so the IM layer can be arranged by adopting the combination of coating and sputtering to meet the comprehensive requirements of adhesive force and color difference.

In a preferred embodiment, a greater number of IM layers may be provided as desired and will not be described in detail herein.

The provision of at least two IM layers allows the reflectance of the IM layer as a whole to be made low to match the low-reflectance conductive layer in the low-resistance conductive film. According to current low resistance technology, the resistance of the conductive layer can be less than 100 ohms, typically 20-25 ohms, with the reflectivity of the conductive layer being 5-6%. Correspondingly, in the present application, the overall reflectivity of at least two IM layers is 4.5-5.5%.

As shown in fig. 3, there is shown a structure of a transparent conductive film comprising: the anti-reflection coating comprises a hard coating layer, an anti-reflection layer, a base material layer, a first IM layer, a second IM layer, a metal doping layer and a transparent conductive material layer.

Wherein, the hard coating is a resin with the refractive index of 1.45-1.55C \ H \ O and the thickness of 0.5-5 um. The antireflection layer is C \ H \ O resin with the refractive index of 1.3-1.4 and the low refractive index, and is doped with F, S and other non-metallic elements; the thickness is 1-8 um.

In order to improve the weather resistance and oxidation resistance of the transparent conductive film, in a preferred embodiment of the present application, a functional film layer with weather resistance, oxidation resistance and the like is disposed in the transparent conductive film.

As one of the embodiments, the transparent conductive film includes: the anti-reflection coating comprises a hard coating layer, an anti-reflection layer, a base material layer, a first IM layer, a second anti-oxidation layer, a metal doping layer, a first anti-oxidation layer and a transparent conductive material layer. The oxidation resistance of the metal doping layer is ensured by arranging the oxidation resistant layers above and below the metal doping layer.

In another embodiment, the transparent conductive film includes, stacked in this order: the anti-reflection coating comprises a hard coating layer, an anti-reflection layer, a base material layer, a first IM layer, a second weather-resistant layer, a metal doping layer, a first weather-resistant layer and a transparent conductive material layer. The weather-resistant layers are arranged above and below the metal doped layer, so that the weather resistance of the metal doped layer is ensured.

In another embodiment, as shown in fig. 4, the transparent conductive film comprises: the anti-reflection coating comprises a hard coating layer, an anti-reflection layer, a base material layer, a first IM layer, a second weather-resistant layer, a second oxidation-resistant layer, a metal doping layer, a first oxidation-resistant layer, a first weather-resistant layer and a transparent conductive material layer. The anti-oxidation layer and the weather-resistant layer are arranged above and below the metal doping layer, so that the anti-oxidation layer and the weather resistance of the metal doping layer are guaranteed.

In other embodiments, the weathering layer and the oxidation resistant layer in the structure shown in fig. 4 may be increased or decreased as desired.

The weather-resistant layer can be non-metal oxide, metal nitride, metal oxide, or dopant (doping material comprises one or more of Al, Ga, Zr, B, Y, Mo, Sn, etc) thereof, such as TiN, ZnO, TiO2, SnO2, SiO2, Si3N4, etc., and dopant includes AZO, IZO, YZO, etc.; the thickness is 2 to 200 nm.

As each of the above-mentioned oxygen-resistant layers, a metal nitride, a metal oxide, or the like, such as Ti, Ni, Cr, NiCr, TiN, ZnO, TiO2, SnO2, SiO2, Nb2O5, Ta2O5, Si3N4, or the like; the thickness can be 0.5 to 10 nm.

The substrate layer can be a flexible substrate such as transparent organic polymers PET, TAC, COP, PEN, CPI, PI. Preferably, PET is selected.

The transparent conductive material layer may be a metal oxide, such as In2O3, SnO2, ZnO, ITO (Sn2O doped at 0-50 wt%), IZO (ZnO doped at 0-50 wt%), AZO (Al2O3 doped at 0-50 wt%); ITiTO (TiO2 doped 0-10% by weight); ITZO (0-10% by weight of doped TIO2, 0-40% by weight of doped ZnO), and FTO (0-10% by weight of doped F).

Another embodiment of the present application further discloses a touch screen, which includes a glass panel, glue and the transparent conductive film sequentially disposed.

Table 1 below shows the conductivity of the prior art and the reflectivity of the IM layer compared to the transparent conductive film in the present application. Wherein the total thickness of the IM layer is not changed and is 2.5 um. The thickness of PET was the same and was 125 um. The thickness of each layer of the ITO layer was constant and was 45 nm. The following items are detected by adopting a detection mode known in the field, and the structure is as follows:

TABLE 1

The data in the table show that the metal doping layer replaces a metal layer, so that the conductivity is improved, and the thickness of the metal doping layer can be set below 10 nm; the provision of dual IM layers reduces the reflectivity of the IM layers.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A transparent conductive film is characterized by comprising a base material, at least two IM layers and a conductive layer which are sequentially stacked;

2. The transparent conductive film according to claim 1, wherein the atomic percent of oxygen or nitrogen in the metal doped layer is 1.5 at% to 5.5 at%.

3. The transparent conductive film according to claim 1, wherein the metal doped layer is a continuous film layer and the thickness of the metal doped layer is less than 10 nm.

4. The transparent conductive film according to claim 1, wherein the metal doped layer is formed by introducing a small amount of O2 and/or N2 during a metal target coating process.

5. The transparent conductive film according to claim 1, wherein the organic material layer is provided by coating and the inorganic material layer is provided by sputtering.

6. The transparent conductive film according to claim 1, wherein the conductive layer has a resistance value of less than 100 ohms; the refractive index of the organic material layer is 1.6-1.7; the refractive index of the inorganic material layer is 1.4-1.6.

7. The transparent conductive film according to claim 1, wherein the conductive layer has an equivalent refractive index of 1.4 to 1.5.

8. The transparent conductive film according to claim 1,

9. The transparent conductive film according to claim 1, wherein the transparent conductive film comprises a hard coat layer, an antireflection layer, the substrate layer, the organic material layer, the inorganic material layer, a second weather-resistant layer, a second antioxidant layer, the metal doping layer, a first antioxidant layer, a first weather-resistant layer, and the transparent conductive material layer, which are sequentially stacked.

10. A touch panel, comprising the transparent conductive film according to any one of claims 1 to 9, and a conductive adhesive and a glass panel sequentially disposed on the transparent conductive film.