Transparent conductive film and manufacturing method thereof

Abstract

The invention provides a transparent conductive film and a manufacturing method thereof.The transparent conductive film comprises a transparent base film, an ITO transparent conductive layer and a conductive metal layer, the ITO transparent conductive layer and the conductive metal layer are communicated with each other, and the conductive metal layer comprises a metal grid and a metal electrode lead. The metal grid and the metal electrode lead are a whole which is communicated with each other and can be processed together in the same production process. The product has the advantages of low sheet resistance, uniform sheet resistance, simple process and the like.

Description

Technical Field

[0001] The invention belongs to the field of conductive films, and in particular relates to a transparent conductive film and a manufacturing method thereof. Background Art

[0002] Conventional electrochromic transparent electrodes use transparent conductive materials such as ITO. The square resistance of ITO (Indium tin oxide) is relatively high, usually 100-200Ω / □. Low-square-resistance ITO can reduce the resistance to 30Ω / □ or 20Ω / □ by thickening the coating or doping it with trace amounts of silver and other metals, but its transmittance will be greatly reduced, and the haze will also increase, sacrificing optical performance. The resistance is difficult to reduce further. At the same time, in order to better transmit current and voltage, a layer of silver paste, copper paste or carbon paste needs to be printed around the ITO film as an electrode lead to better transmit current.

[0003] There are also solutions combining ITO and metal mesh in the existing technology, but this conductive film also needs to be printed with a layer of silver paste, copper paste or carbon paste as electrode leads according to the shape of the product, which requires an additional printing process, resulting in increased costs for materials, labor and power media. In addition, the added process will also reduce the product yield and further increase the production cost of the product. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a transparent conductive film and a method for manufacturing the same. The transparent conductive film manufactured by the method combines the two advantages of the square resistance uniformity of ITO and the low resistance of the metal grid, and no longer needs to print electrode leads, thereby achieving the purpose of improving product performance, reducing processes, and reducing product costs.

[0005] Specifically, the present invention provides a transparent conductive film, wherein the transparent conductive film includes a transparent base film, an ITO transparent conductive layer, and a conductive metal layer, the ITO transparent conductive layer and the conductive metal layer are electrically connected to each other, the conductive metal layer includes a metal grid and a metal electrode lead, and the metal grid and the metal electrode lead are an integral whole.

[0006] Furthermore, the material of the transparent base film can be optical-grade glass, PET, PC, COP, CPI, PMMA or other materials with excellent optical properties.

[0007] Furthermore, the material of the conductive metal layer can be gold, silver, copper, aluminum and other metals with low resistance. Considering the convenience of subsequent etching process and the anti-oxidation and salt spray test requirements of the product after etching, the conductive material will also add nickel, titanium, molybdenum, chromium, palladium and other metals.

[0008] Furthermore, the conductive metal layer can be realized by magnetron sputtering, evaporation, electroplating or coating.

[0009] Specifically, the present invention also provides a method for manufacturing the transparent conductive film, which comprises the following steps: (a) sputtering an ITO transparent conductive layer on one surface of the transparent base film; (b) adding a conductive metal layer on the surface of the ITO transparent conductive layer, wherein the metal grid and the metal electrode lead structure on the conductive metal layer are integrated; (c) coating a photoresist layer on the surface of the conductive metal layer; (d) Exposure, exposing the required pattern on the photoresist layer to form a latent image; (e) Development, using a developer to dissolve the latent image portion, exposing the metal of the conductive metal layer at that location, and retaining the remaining photoresist layer to protect the conductive metal layer underneath; (f) etching, using an etchant to etch away the exposed conductive metal layer in the previous step, leaving only the metal grid and metal electrode lead pattern protected by the remaining photoresist layer; (g) Stripping: Use a stripping solution to peel off the remaining photoresist layer to obtain a transparent conductive film.

[0010] Furthermore, the material of the photoresist layer can be a commercially available photosensitive dry film, or a liquid photoresist, and can be a positive photoresist or a negative photoresist.

[0011] Furthermore, the exposure in step (d) can be performed by using a mask plate exposure method, where a circuit pattern is drawn on the mask plate, the mask plate is attached to the surface of the photoresist, and then the mask plate is exposed, and the pattern on the mask plate is transferred to the photoresist to form a latent image. The mask plate can be a chrome plate, a glass dry plate, a film plate, etc.; laser direct writing can also be used to scan the required pattern directly on the photoresist to form a latent image.

[0012] Furthermore, during the etching process in step (f), the etching solution will only etch the conductive metal layer without causing substantial damage to the ITO transparent conductive layer, thereby affecting its conductivity.

[0013] It can be understood that, since the conductive metal layer can be used for laying out the metal grid and the metal electrode leads at the same time, the metal grid and the metal electrode leads are manufactured simultaneously.

[0014] Furthermore, the shape of the metal grid is not particularly limited. It can be a very thin line bent to form various circuit patterns, or it can be a regular polygon, such as a triangle, quadrilateral, pentagon, hexagon... or even a circle, etc. In some preferred embodiments, the shape of the metal grid is a square, a diamond grid, a hexagon, a random polygon, a random curve, a randomly twisted diamond, etc.

[0015] In some specific embodiments, considering the condition of the same aperture ratio, the product requires higher transmittance and lower square resistance, and the metal grid is preferably a regular hexagonal grid.

[0016] In some specific embodiments, considering the mutual interference of the grids after the two layers are bonded, resulting in the appearance of moiré interference fringes, the metal grid is preferably a grid with a specific angle, or the above-mentioned random pattern.

[0017] The present invention provides a transparent conductive film in which the metal grid and the metal electrode lead are integrated as a whole and can be processed together in the same production process. There is no need to print a layer of silver paste, copper paste or carbon paste around them as electrode leads, and no additional printing process is required, thereby effectively reducing the cost of materials, labor and power media.

[0018] The metal grid and the metal electrode leads are processed together as a whole in the same production process, so that the thickness of the conductive metal layer becomes thinner, and then the thickness of the entire transparent conductive film becomes thinner, which enhances the flexibility of the transparent conductive film and improves the use effect of the transparent conductive film.

[0019] In addition, the simplification of the process will also improve the yield of the product and further reduce the production cost of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a transparent conductive film provided by the present invention; Figure 2 A schematic structural diagram of a conductive metal layer of a transparent conductive film provided by the present invention; Figure 3 It is a schematic diagram of the structure after the transparent conductive film is coated with a photoresist layer; Figure 4 It is a schematic diagram of the structure of a transparent conductive film coated with a photoresist layer after exposure; Figure 5 is a schematic diagram of the structure of the transparent conductive film after etching after exposure; Figure 6 It is a schematic diagram of the structure of the transparent conductive film after being stripped after etching; Figure 7 It is a schematic diagram of the structure of a square metal grid; Figure 8 It is a schematic diagram of the structure of a diamond-shaped metal grid; Fig. 9 It is a schematic diagram of the structure of a hexagonal metal grid; Fig.10 It is a schematic diagram of the structure of a random polygonal metal mesh; In the figure: 1-transparent base film, 2-ITO transparent conductive layer, 3-conductive metal layer, 3-1-metal grid, 3-2-metal electrode lead, 4-photoresist layer, 4-1-remaining photoresist layer. Implementation

[0021] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0022] See also Figure 1-Figure 2 This embodiment provides a transparent conductive film, which includes a transparent base film 1, an ITO transparent conductive layer 2, and a conductive metal layer 3. The ITO transparent conductive layer 2 and the conductive metal layer 3 are mutually conductive. The conductive metal layer 3 includes a metal grid 3-1 and a metal electrode lead 3-2. The metal grid 3-1 and the metal electrode lead 3-2 are a whole.

[0023] The material of the transparent base film 1 can be optical-grade glass, PET, PC, COP, CPI, PMMA or other materials with excellent optical properties.

[0024] The material of the conductive metal layer 3 can be gold, silver, copper, aluminum and other metals with low resistance. Considering the convenience of subsequent etching process and the requirements of anti-oxidation and salt spray test of the product after etching, the conductive material will also add nickel, titanium, molybdenum, chromium, palladium and other metals.

[0025] The conductive metal layer 3 can be formed by magnetron sputtering, evaporation, electroplating or coating.

[0026] This embodiment also provides a method for manufacturing the transparent conductive film, which comprises the following steps: (a) sputtering an ITO transparent conductive layer 2 on any surface of a transparent base film 1; (b) Adding a conductive metal layer 3 on the other surface of the ITO transparent conductive layer 2, the conductive metal layer 3 includes a metal grid 3-1 and a metal electrode lead 3-2, wherein the metal grid 3-1 and the metal electrode lead 3-2 are processed together as a whole in the same production process. The metal grid 3-1 and the metal electrode lead 3-2 are interconnected, the metal grid 3-1 is similar to the fine veins on a leaf, and the metal electrode lead 3-2 is similar to the large veins and petiole on the leaf. During production, the images of the metal grid 3-1 and the metal electrode lead 3-2 are made on the same plate, and the photosensitive material is coated, and the plate with the images of the metal grid 3-1 and the metal electrode lead 3-2 prepared above is exposed, and then developed, etched, and finally stripped, so that the metal grid 3-1 and the metal electrode lead 3-2 are made on the substrate as a whole. Preferably, opaque copper is used to make the metal grid 3-1 and the metal electrode lead 3-2; (c) Coating a photoresist layer 4 on the surface of the conductive metal layer 3 (see Figure 3 ); (d) exposing the desired pattern to the photoresist layer 4 to form a latent image; (e) Development: using a developer to dissolve the latent image portion, so that the conductive metal layer 3 is exposed at that portion, and the remaining photoresist layer 4-1 at the non-latent image portion is still retained to protect the conductive metal layer 3 below (see Figure 4 ); (f) Etching: using an etchant to etch away the exposed conductive metal layer 3 in the previous step, leaving only the metal grid 3-1 and the metal electrode lead 3-2 protected by the remaining photoresist layer 4-1, thereby forming the desired circuit pattern (see Figure 5 ); (g) Stripping: The remaining photoresist layer 4-1 is stripped off with a stripping solution to obtain a transparent conductive film (see Figure 6 ).

[0027] The exposure in step (d) can be performed by using a mask plate exposure method. The mask plate has a circuit pattern drawn on it. The mask plate is attached to the surface of the photoresist, and then the mask plate is exposed. The pattern on the mask plate is transferred to the photoresist to form a latent image. The mask plate can be a chrome plate, a glass dry plate, a film plate, etc.; laser direct writing can also be used to scan the required pattern directly on the photoresist to form a latent image.

[0028] During the etching process in step (f), the etching solution will only etch the conductive metal layer, but will not cause substantial damage to the ITO transparent conductive layer 2, thereby affecting its conductivity.

[0029] It can be understood that, since the conductive metal layer 3 can be used for laying out the metal grid 3-1 and the metal electrode lead 3-2 at the same time, the metal grid 3-1 and the metal electrode lead 3-2 are manufactured synchronously.

[0030] The shape of the metal grid 3-1 is not particularly limited, and can be a very thin line bent to form various circuit patterns, or a regular polygon, such as a triangle, a quadrilateral, a pentagon, a hexagon, or even a circle, etc. In some preferred embodiments, the shape of the metal grid 3 is a square grid (see Figure 7 ), diamond grid (see Figure 8 ), hexagon (see Fig. 9 ), random polygons (see Fig.10 ), random curves, random twisted diamonds, and more.

[0031] In this embodiment, considering the condition of the same aperture ratio, the product requires higher transmittance and lower square resistance, and the metal grid 3-1 is preferably a regular hexagonal grid.

[0032] In other embodiments, considering the mutual interference of the grids after the two layers are bonded together and the appearance of moiré interference fringes, the metal grid 3-1 is preferably a grid with a specific angle, or the above-mentioned random pattern.

[0033] The above-mentioned embodiments are described in detail and are not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the relevant art, several modifications and improvements may be made without departing from the present concept, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A transparent conductive film, characterized in that: The transparent conductive film comprises a transparent base film (1), an ITO transparent conductive layer (2), and a conductive metal layer (3). The ITO transparent conductive layer (2) and the conductive metal layer (3) are electrically connected to each other. The conductive metal layer (3) comprises a metal grid (3-1) and a metal electrode lead (3-2). The metal grid (3-1) and the metal electrode lead (3-2) are an integral whole.

2. The transparent conductive film according to claim 1, characterized in that: The material of the transparent base film (1) is selected from one of optical grade glass, PET, PC, COP, CPI and PMMA.

3. The transparent conductive film according to claim 1, characterized in that: The material of the conductive metal layer (3) is selected from one or an alloy of gold, silver, copper, aluminum, nickel, titanium, molybdenum, chromium and palladium.

4. The transparent conductive film according to claim 1, characterized in that: The conductive metal layer (3) is achieved by magnetron sputtering, evaporation, electroplating or coating.

5. The method for producing a transparent conductive film according to any one of claims 1 to 4, characterized in that: The production method comprises the following steps: (a) sputtering an ITO transparent conductive layer (2) on one surface of a transparent base film (1); (b) adding a conductive metal layer (3) on the surface of the ITO transparent conductive layer (2), wherein the metal grid (3-1) and the metal electrode lead (3-2) on the conductive metal layer (3) are structured as a whole; (c) coating a photoresist layer (4) on the surface of the conductive metal layer (3); (d) exposing the desired pattern onto the photoresist layer (4) to form a latent image; (e) developing, using a developer to dissolve the latent image portion, so that the metal of the conductive metal layer (3) at that location is exposed, and the remaining photoresist layer (4-1) is still retained to protect the conductive metal layer (3) below; (f) etching, using an etchant to etch away the exposed conductive metal layer (3) in the previous step, leaving only the metal grid (3-1) and the metal electrode lead (3-2) pattern protected by the remaining photoresist layer (4-1); (g) Stripping: using a stripping solution to peel off the remaining photoresist layer (4-1) to obtain a transparent conductive film.

6. The method according to claim 5, characterized in that: The material of the photoresist layer (4) is selected from a photosensitive dry film and a liquid photoresist.

7. The manufacturing method according to claim 5, characterized in that: The photoresist layer (4) is a positive photoresist or a negative photoresist.

8. The manufacturing method according to claim 5, characterized in that: The exposure in step (d) is performed by mask or laser direct writing.

9. The manufacturing method according to claim 5, characterized in that: During the etching process described in step (f), the etching solution will only etch the conductive metal layer (3) without causing substantial damage to the ITO transparent conductive layer (2).

10. The manufacturing method according to claim 5, characterized in that: The shape of the metal grid (3-1) is a regular polygon, a circle, a random polygon, a random curve, or a randomly twisted rhombus.

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