Transparent conductive film, touch screen and preparation method thereof

Abstract

The present invention relates to a transparent conductive film, which includes a first hard coating, a first transparent conductive layer and a first metal layer formed in sequence on the first surface of a substrate, and a second hard coating, a second transparent conductive layer and a second metal layer on the second surface of the substrate. Particles form a plurality of protrusions on the surface of the first metal layer. Among them, the range of the height Rz of the plurality of protrusions is 0.25 μm < Rz < 0.5 μm. The protrusions endow the transparent conductive film with an anti-adhesion function. Moreover, compared with the traditional conductive film, the height of the protrusions is reduced, so the height difference between the protrusions is also reduced, thereby reducing the roughness of the surface of the hard coating. Therefore, the crystallinity of the conductive layer formed on the surface of the hard coating is improved, resulting in uniform sheet resistance. Moreover, since only the first hard coating contains particles, the roughness of the surface of the second hard coating is further reduced. Therefore, the quality of the above-mentioned transparent conductive film is effectively improved. In addition, the present invention also provides a touch screen and a method for preparing the same.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitive touch screens, and in particular to a transparent conductive film, a touch screen and a preparation method thereof. Background Art

[0002] Transparent conductive films are a core component of capacitive touchscreens. With the rapid development of smart devices, the demand for transparent conductive films is increasing. Transparent conductive films generally consist of a substrate with a hard coating layer, a conductive layer, and a metal layer disposed on both sides of the substrate. Currently, most transparent conductive films use amorphous polymer films as substrates, as amorphous polymer films have a lower and more uniform birefringence than crystalline polymer films.

[0003] Amorphous polymer films are more fragile than crystalline polymer films and their surfaces are more susceptible to damage. When rolling a transparent conductive film into a cylindrical shape, the metal layers of adjacent transparent conductive films can stick together and press together. Therefore, transparent conductive films have been developed that incorporate particles into the hard coat layer to create raised bumps on the metal layer surface. These bumps allow adjacent metal layers to form point contact, thus preventing sticking and pressing together.

[0004] However, the protrusions will cause the surface of the hard coating to have height differences, thereby increasing the surface roughness of the hard coating. This will affect the crystallinity of the conductive layer, resulting in uneven square resistance, and thus poor quality of the conductive film. Summary of the Invention

[0005] Based on this, it is necessary to provide a transparent conductive film, touch screen and preparation method thereof that can effectively improve the quality, in order to solve the problem that the existing transparent conductive film with anti-adhesion function has uneven resistance and poor quality.

[0006] A transparent conductive film, comprising:

[0007] A substrate comprising a first surface and a second surface disposed opposite to each other;

[0008] forming a first hard coating layer, a first transparent conductive layer, and a first metal layer in sequence on the first surface;

[0009] forming a second hard coating layer, a second transparent conductive layer, and a second metal layer in sequence on the second surface;

[0010] The first hard coating layer contains a plurality of particles to form a plurality of protrusions on the surface of the first metal layer, and the height Rz of the plurality of protrusions is in the range of 0.25 μm. <Rz<0.5μm。

[0011] Due to the existence of the protrusions, the transparent conductive film has an anti-adhesion function. Moreover, the height Rz of the protrusions ranges from 0.25 μm < Rz < 0.5 μm. Compared with traditional conductive films, while meeting the anti-adhesion requirements, the height of the protrusions is effectively reduced, so the height difference between the protrusions is also reduced, thereby reducing the surface roughness of the hard coating. Further, the crystallinity of the conductive layer formed on the surface of the hard coating is improved, making the sheet resistance uniform. Moreover, since only the first hard coating contains particles, the surface roughness of the second hard coating is further reduced. Therefore, the quality of the above-mentioned transparent conductive film is effectively improved.

[0012] In addition, due to the reduction of the surface roughness of the hard coating, the flatness of the subsequent formed conductive layer and metal layer is also increased, thereby further improving the anti-cracking performance of the above-mentioned transparent conductive film.

[0013] In one embodiment, the distribution density of the protrusions is 100 to 3000 per mm 2 .

[0014] When the distribution density of the protrusions is too large, the haze value of the transparent conductive film will be too large and the light transmittance will decrease, which will seriously affect the appearance and optical effect of the transparent conductive film. If the distribution density of the protrusions is too small, the anti-adhesion effect will be limited. Within the above roughness and density ranges, the transparent conductive film can better balance the anti-adhesion and optical effects.

[0015] In one embodiment, the particles have the same material as the first hard coating.

[0016] That is to say, the particles and the first hard coating also have the same optical parameters. Therefore, at the connection interface between the particles and the first hard coating, the influence on the light propagation is small, and the particles and the first hard coating are closer to being a whole. When light passes through the first hard coating containing particles, the distortion of its propagation route is small. Therefore, while achieving the purposes of anti-adhesion and anti-compression connection, the transparent conductive film can also avoid adverse effects on its optical properties.

[0017] In one embodiment, there is a gap between the plurality of particles and the surface of the substrate.

[0018] The higher the height of the protrusions, the better the anti-adhesion effect. However, as the height increases, the size of the particles needs to increase accordingly, resulting in an increase in the haze value of the transparent conductive film.

[0019] However, in the present invention, since there is a gap between the particles and the surface of the substrate, it is equivalent to the particles being suspended in the first hard coating. Therefore, compared with traditional conductive films, while the height of the protrusions remains unchanged, it is beneficial to reduce the particle size, thereby reducing the haze.

[0020] In one embodiment, the particles are in the shape of elongated strips, and the size of the particles in a direction perpendicular to the first surface is larger than the size in a direction parallel to the first surface.

[0021] Conventional particles are spherical or amorphous, with comparable transverse (parallel to the substrate surface) and longitudinal (perpendicular to the substrate surface) dimensions. Therefore, to increase the height of the protrusions, both longitudinal and transverse dimensions must be increased proportionally. However, due to the excessively large transverse dimensions, the light-blocking effect of the particles becomes more pronounced, leading to increased haze in the conductive film.

[0022] In the present invention, the particles are elongated, and their dimensions in the direction perpendicular to the first surface (longitudinal direction) are larger than their dimensions in the direction parallel to the first surface (lateral direction). In other words, the longitudinal and lateral dimensions of the particles are relatively large. Therefore, even if the height of the protrusions increases, the lateral dimensions of the particles can be maintained within a relatively small range, thereby effectively reducing haze while improving anti-blocking effects.

[0023] In one embodiment, the particles are arranged perpendicularly relative to the first surface.

[0024] The ratio of the longitudinal to lateral dimensions of the particles can be further increased, thereby further reducing the haze of the transparent conductive film when the protrusion height remains the same.

[0025] In one embodiment, the center of gravity of the particle is located at an end of the particle close to the substrate.

[0026] When preparing a transparent conductive film, a layer of fluid adhesive resin is first applied to the first surface of the substrate. Before the adhesive resin solidifies, prefabricated particles are sprayed on it. The particles naturally settle under the action of gravity until they are embedded in the hard coating layer. Finally, the adhesive resin is cured to obtain a first hard coating layer containing the particles.

[0027] Because the center of gravity of the particles is located at the end closest to the substrate, that is, the particles have an offset center of gravity. Therefore, during natural settling, the particles can flip themselves under the influence of gravity and ultimately become fixed in the first hard coating layer in a direction perpendicular or approximately perpendicular to the first surface. Because the particles can be arranged in a predetermined configuration without requiring additional manipulation, the preparation process for the transparent conductive film can be simplified.

[0028] In one embodiment, the particle includes a solid region and a hollow region, wherein the solid region is located at one end of the particle close to the substrate, and the hollow region is located at the other end of the particle.

[0029] By providing solid and hollow regions, the center of gravity of the particle can be shifted. Furthermore, the hollow regions can be formed in a variety of ways, thereby improving the efficiency of transparent conductive film production and reducing costs.

[0030] A touch screen, the touch screen being made of the transparent conductive film described in any one of the above preferred embodiments, the touch screen comprising a touch area and a lead area, the first metal layer and the second metal layer being located in the lead area; the touch area comprising a first electrode formed by etching the first transparent conductive layer, and a second electrode formed by etching the second transparent conductive layer; the lead area comprising a first lead formed by etching the first metal layer and the first transparent conductive layer located in the lead area, and a second lead formed by etching the second metal layer and the second transparent conductive layer located in the lead area.

[0031] In this touchscreen, the first and second leads are directly etched from the first metal layer, the second metal layer, the first transparent conductive layer, and the second transparent conductive layer. Therefore, there is no need to form the leads electrically connecting the first and second electrodes through silk screen printing. Compared to traditional touchscreens, the electrode leads formed directly through the photolithography process can be further reduced in width due to the lack of silk screen printing, resulting in a narrower bezel.

[0032] A method for preparing a touch screen comprises the following steps:

[0033] Providing a transparent conductive film as described in any one of the above preferred embodiments;

[0034] Etching the first metal layer and the second metal layer to expose the first transparent conductive layer and the second transparent conductive layer in the touch area, and forming a metal lead pattern in the lead area;

[0035] The first transparent conductive layer and the second transparent conductive layer are etched to form a first electrode and a second electrode in the touch area, and a transparent lead pattern in the lead area. The metal lead pattern and the transparent lead pattern together constitute electrode leads.

[0036] When fabricating a touch screen using this method, the first and second metal layers, as well as the first and second transparent conductive layers, are directly etched to form the first and second electrodes, along with the electrode leads electrically connected to them. This eliminates the need for screen printing to form leads, effectively simplifying the process and improving efficiency. Furthermore, the touch screen fabricated using this method exhibits a narrow bezel. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the stacked structure of the transparent conductive film in a preferred embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of a stacked structure of a transparent conductive film in another embodiment of the present invention;

[0039] Figure 3 for Figure 2 A cross-sectional view of particles in the transparent conductive film;

[0040] Figure 4 Schematic diagram of the stacked structure of the touch screen in a preferred embodiment of the present invention;

[0041] Figure 5 Schematic diagram of the process of manufacturing a touch screen in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0042] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0043] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] See also Figure 1 The transparent conductive film 10 in a preferred embodiment of the present invention includes a substrate 11 , a first hard coating layer 12 , a first transparent conductive layer 13 , a first metal layer 14 , a second hard coating layer 22 , a second transparent conductive layer 23 and a second metal layer 24 .

[0046] The substrate 11 includes a first surface ( Figure 1 shown upper surface) and the second surface ( Figure 1The first surface and the second surface are only used to distinguish the two surfaces of the substrate 11, and the positions of the first surface and the second surface are interchangeable. The substrate 11 is formed of an amorphous polymer film. Since the birefringence of the amorphous polymer film is smaller and more uniform than that of the crystalline polymer film, the color unevenness in the transparent conductive film 10 of the present invention can be eliminated. The in-plane birefringence of the amorphous polymer film used in the present invention is preferably 0 to 0.001, and more preferably 0 to 0.0005. The deviation of the in-plane birefringence of the amorphous polymer film used in the present invention is preferably 0.0005 or less, and more preferably 0.0003 or less.

[0047] The aforementioned birefringence and its deviation can be achieved by selecting an appropriate type of amorphous polymer film. Specifically, in this embodiment, substrate 11 is a polycycloolefin, polycarbonate, or polyethylene terephthalate film. These two types of films can meet the requirements for birefringence and its deviation. The thickness of substrate 11 formed of amorphous polymer film is 20 μm to 200 μm.

[0048] The first hard coating layer 12, the first transparent conductive layer 13 and the first metal layer 14 are sequentially formed on the first surface of the substrate 11. The second hard coating layer 22, the second transparent conductive layer 23 and the second metal layer 24 are sequentially formed on the second surface of the substrate 11.

[0049] The first hard coating layer 12 protects the first surface of the substrate 11. The first hard coating layer 12 includes a binder resin. The binder resin includes, for example, a curable resin composition based on ultraviolet rays or electron beams. The curable resin composition preferably includes a polymer obtained by an addition reaction between a glycidyl acrylate polymer and acrylic acid. Alternatively, the curable resin composition preferably includes a multifunctional acrylate polymer (pentaerythritol, dipentaerythritol, etc.). The curable resin composition further includes a polymerization initiator.

[0050] The first transparent conductive layer 13 is formed on the surface of the first hard coat layer 12. The first transparent conductive layer 13 has a high transmittance (80% or more) in the visible light region (380nm to 780nm) and a surface resistance value per unit area (unit: Ω / m 2 ) is 500Ω / m 2 The following layers are formed. The thickness of the first transparent conductive layer 13 is preferably 15 nm to 100 nm, more preferably 15 nm to 50 nm. The first transparent conductive layer 13 is formed of, for example, indium tin oxide (ITO), indium tin oxide, or an indium oxide-zinc oxide composite.

[0051] The first metal layer 14 is formed on the surface of the first transparent conductive layer 13. When the transparent conductive film of the present invention is used for, for example, a touch panel, the first metal layer 14 is used to form wirings outside the touch input area. Regarding the material for forming the first metal layer 15, typical ones are copper and silver, and any other metal with excellent conductivity can also be used. The thickness of the first metal layer 14 is preferably 50 nm to 500 nm, and more preferably 100 nm to 300 nm.

[0052] Furthermore, the second hard coating 22, the second transparent conductive layer 23, and the second metal layer 24 have the same film layer structure, functions, and material compositions as the first hard coating 12, the first transparent conductive layer 13, and the first metal layer 14 respectively, so they will not be elaborated here.

[0053] In addition, the first hard coating 12 contains multiple particles 15 to form multiple protrusions 16 on the surface of the first metal layer 14. Moreover, the height Rz of the multiple protrusions 16 ranges from 0.25 μm < Rz < 0.5 μm. Therefore, compared with the existing conductive films having an anti-adhesion function, the height of the protrusions 16 in the transparent conductive film 10 is significantly reduced. Here, the height of the protrusion 16 refers to the height by which the protrusion 16 protrudes from the surface of the first metal layer 14.

[0054] It should be noted that since the size of the particles 15 is small, it is difficult to precisely control the height of each protrusion 16. Therefore, it is sufficient to control the height of the protrusions 16 within the above height range. Further, in actual production, since it is difficult to accurately control each particle 15, it is inevitable that the height of the protrusions 16 formed by a very small number of particles 15 is outside the above range. However, the influence caused by these protrusions 16 can be ignored. In addition, the height Rz can also refer to the average value of the heights of a certain number of protrusions 16 within a preset range.

[0055] Specifically, the particles 15 can be distributed irregularly or according to a preset rule (such as evenly) within the first hard coating 12. The particles 15 can be spherical particles or particles of other shapes.

[0056] The particles 15 are only contained within the first hard coating 12, thereby obtaining the transparent conductive film 10 with protrusions 16 formed on one side. The process of forming the protrusions 16 by the particles 15 is as follows:

[0057] The particles 15 protrude from the surface of the first hard coating 12, so that the surface of the first hard coating 12 forms a convex region, while the region of the first hard coating 12 without the particles 15 forms a flat region 17. Since the first transparent conductive layer 13 and the first metal layer 14 are sequentially stacked on the surface of the first hard coating 12, the surface shapes of the two are the same as the surface shape of the first hard coating 12. Therefore, in the region corresponding to the particles 14 on the first metal layer 14, a plurality of protrusions 16 will be formed.

[0058] When manufacturing the long transparent conductive film 10 by using the roll-to-roll process, since the particles 15 cause a plurality of protrusions 16 to be formed on the surface of the first metal layer 14. Therefore, when curling the transparent conductive film 10, the plurality of protrusions 16 can form point contacts between adjacent two metal layers, thereby preventing them from sticking and crimping to each other.

[0059] Moreover, the height Rz of the protrusions 16 ranges from 0.25 μm < Rz < 0.5 μm. Compared with the traditional conductive film, while meeting the anti-sticking requirement, the height of the protrusions 16 is reduced, so the height difference between the protrusions 16 is also reduced, and further the roughness of the hard coating surface is reduced. Further, the crystallinity of the conductive layer formed on the hard coating surface is improved, so that the sheet resistance is uniform. Moreover, since only the first hard coating 12 contains particles, the roughness of the surface of the second hard coating 22 is further reduced. Therefore, the quality of the transparent conductive film 10 is effectively improved.

[0060] In addition, since the roughness of the hard coating surface is reduced, the flatness of the subsequent formed conductive layer and metal layer is also increased, thereby further improving the crack resistance of the transparent conductive film 10.

[0061] In this embodiment, the particles 15 are made of the same material as the first hard coating 12.

[0062] Since the particles 15 are made of the same material as the first hard coating, their optical parameters are also the same. Therefore, at the connection interface between the particles 15 and the first hard coating 12, the influence on the light propagation is small, and the particles 15 and the first hard coating 12 are closer to being a whole. When the light passes through the first hard coating 12 containing the particles 15, the distortion of its propagation route is small. Therefore, while the transparent conductive film 10 achieves the purposes of anti-sticking and anti-crimping, it can also avoid adverse effects on its optical performance.

[0063] Further, in this embodiment, the material of the particles 15 is silicon dioxide, silicone polymer, acrylic polymer or styrene polymer.

[0064] The above materials have the advantages of good light transmittance and easy availability, and their use in particles 15 can reduce costs while meeting performance requirements. Of course, other suitable materials can also be selected based on actual performance and cost requirements.

[0065] In this embodiment, the distribution density of the protrusions 16 is 100 to 3000 per mm. 2 .

[0066] If the density of the protrusions 16 is too high, the haze value of the transparent conductive film 10 will be too high, and the light transmittance will be reduced, which will seriously affect the appearance and optical performance of the transparent conductive film 10. If the density of the protrusions 16 is too low, the anti-blocking effect will be limited. Within the above density range, the transparent conductive film 10 can achieve a good balance between anti-blocking and optical performance.

[0067] See also Figure 2 and Figure 3 In another embodiment of the present invention, the particle 15 is in an elongated shape, and the size of the particle 15 in a direction perpendicular to the first surface is larger than the size in a direction parallel to the first surface.

[0068] Conventional particles are spherical or amorphous, with comparable transverse (parallel to the substrate surface) and longitudinal (perpendicular to the substrate surface) dimensions. Therefore, when the height of protrusions 16 is increased, both longitudinal and transverse dimensions must be increased proportionally. However, when the transverse dimensions of particles 15 are too large, the light-blocking effect caused by particles 15 becomes more pronounced, resulting in increased haze in the conductive film.

[0069] Because the particles 15 in this embodiment are elongated, when the particles 15 are positioned perpendicular or approximately perpendicular to the first surface, the size of the particles 15 in the direction perpendicular to the first surface (longitudinal direction) is larger than the size in the direction parallel to the first surface (lateral direction). In other words, the longitudinal and lateral dimensions of the particles are relatively large. Therefore, even if the height of the protrusions 16 increases, the lateral dimensions of the particles 15 can still be maintained within a relatively small range, thereby improving the anti-blocking effect of the transparent conductive film 10 while effectively reducing its haze.

[0070] Furthermore, in this embodiment, the particles 15 are arranged perpendicularly to the first surface.

[0071] At this time, the ratio of the longitudinal to lateral dimensions of the particles 15 is maximized, so that the haze of the transparent conductive film 10 can be further reduced when the height of the protrusions 16 remains the same.

[0072] In this embodiment, the center of gravity of the particle 15 is located at an end of the particle 15 close to the substrate 11 .

[0073] When preparing the transparent conductive film 10, a layer of fluid adhesive resin is first applied to the first surface of the substrate 11. Before the adhesive resin cures, prefabricated particles 15 are sprayed thereon. The particles 15 naturally settle under the action of gravity until they are embedded in the hard coating layer. Finally, the adhesive resin is cured to obtain a first hard coating layer 12 containing the particles.

[0074] Because the center of gravity of the particles 15 is located at the end closest to the substrate 11, that is, the particles 15 have an offset center of gravity. Therefore, similar to the principle of a tumbler, the particles 15 can naturally flip over under the action of gravity during natural settling and ultimately become fixed in the first hard coating layer 12 in a direction perpendicular or approximately perpendicular to the first surface. Since the particles 15 can be arranged in a predetermined configuration without requiring additional steps, the preparation process of the transparent conductive film 10 can be simplified.

[0075] In this embodiment, the particle 15 includes a solid region 151 and a hollow region 153 . The solid region 151 is located at one end of the particle 151 close to the substrate 11 , and the hollow region 153 is located at the other end of the particle 15 .

[0076] Specifically, by providing the solid region 151 and the hollow region 153, the center of gravity of the particle 15 can be offset. Furthermore, the hollow region 153 can be formed on the particle 15 in a variety of ways, such as by air blowing or phase separation. This improves the efficiency of prefabrication of the particle 15, thereby increasing the efficiency of manufacturing the transparent conductive film 10 and reducing costs.

[0077] In another embodiment, gaps exist between the plurality of particles 15 and the surface of the substrate 11 .

[0078] Therefore, the particles 15 are essentially suspended in the first hard coating layer 12 and do not directly contact the substrate 11. In existing anti-adhesion conductive films, the particle size must be larger than the thickness of the hard coating layer; otherwise, no protrusions can be formed on the surface of the metal layer. Therefore, the particle size is limited by the thickness of the hard coating layer and cannot be further reduced.

[0079] In this embodiment, the particles 15 are suspended within the first hard coating layer 12. Therefore, even if the particle size of the particles 15 is smaller than the thickness of the hard coating layer, it does not affect the formation of protrusions 16 on the surface of the first metal layer 14. In other words, the particle size of the particles 15 is not limited by the thickness of the hard coating layer, and the particle size of the suspended particles 15 can be further reduced, thereby reducing the haze value, increasing light transmittance, and ultimately improving the optical effect.

[0080] In order to achieve better anti-adhesion and anti-compression effects, there are corresponding requirements for the density of the surface protrusions 16 of the first metal layer 14 and the second metal layer 24 .

[0081] In the above-mentioned transparent conductive film 10, due to the existence of the protrusions 16, the transparent conductive film 10 has an anti-adhesion function. Moreover, the range of the height Rz of the protrusions 16 is 0.25um < Rz < 0.5μm. Compared with the traditional conductive film, while meeting the anti-adhesion requirement, the height of the protrusions 16 is reduced, so the height difference between the protrusions 16 is also reduced, thereby reducing the surface roughness of the hard coating. Further, the crystallinity of the conductive layer formed on the surface of the hard coating is improved, so that the sheet resistance is uniform. Moreover, since only the first hard coating 12 contains particles, the surface roughness of the second hard coating 22 is further reduced. Therefore, the quality of the above-mentioned transparent conductive film 10 is effectively improved.

[0082] In addition, the present invention also provides a touch screen. Please refer to Figure 4 together. The touch screen 200 in the preferred embodiment of the present invention is made of the transparent conductive film 1 in the above-mentioned embodiment. Among them:

[0083] The touch screen 200 includes a touch area 210 and a lead area 220. Specifically, the touch area 210 is located in the middle of the touch screen 200, and the lead area 220 is arranged around the circumference of the touch area 210. The first metal layer 14 and the second metal layer 24 are located in the lead area 220.

[0084] The touch area 210 includes a first electrode 211 and a second electrode 212. Among them, the first electrode 211 is formed by etching the first transparent conductive layer 13; the second electrode 212 is formed by etching the second transparent conductive layer 23. The first electrode 211 and the second electrode 212 are etched into electrode patterns. Specifically, the electrode patterns are generally strip-shaped and vertically intersect to form a grid shape, and the opposite first electrode 211 and second electrode 212 form two poles of a capacitive structure.

[0085] The lead area 220 includes a first lead 221 and a second lead 222. The first lead 221 is formed by etching the first metal layer 14 and the first transparent conductive layer 13 located in the lead area 220; the second lead 222 is formed by etching the second metal layer 24 and the second transparent conductive layer 23 located in the lead area 220. The first lead 221 and the second lead 222 are of a double-layer structure, so as to realize electrical connection with the first electrode 211 and the second electrode 212.

[0086] In the above-mentioned touch screen, the first lead 221 and the second lead 222 are directly etched from the first metal layer 14, the second metal layer 24, the first transparent conductive layer 13 and the second transparent conductive layer 23. Therefore, since there is no need for screen printing, the width of the electrode leads formed directly by the yellow light process can be further reduced, so the touch screen has a narrow border.

[0087] Please refer to Figure 5The present invention also provides a method for preparing a touch screen, which includes steps S310 to S330:

[0088] Step S310: providing a transparent conductive film.

[0089] Specifically, the transparent conductive film is the transparent conductive film 10 in the above embodiment, which includes a first transparent conductive layer 13 and a first metal layer 14 stacked together, and a second transparent conductive layer 23 and a second metal layer 24 stacked together.

[0090] Step S320: Etching the first metal layer 14 and the second metal layer 24 to expose the first transparent conductive layer 13 and the second transparent conductive layer 23 in the touch area and forming a metal lead pattern in the lead area

[0091] Specifically, a metal lead pattern can be formed on the surface of the metal layer through a yellow light process. The metal lead pattern is arranged along the edge of the touch screen. After the metal layer is etched, the first transparent conductive layer 13 and the second transparent conductive layer 24 below are partially exposed.

[0092] In step S330 , the first transparent conductive layer 13 and the second transparent conductive layer 23 are etched to form the first electrode 211 and the second electrode 212 in the touch area, and a transparent lead pattern in the lead area. The metal lead pattern and the transparent lead pattern together constitute electrode leads.

[0093] Specifically, another yellow light process is used to etch the exposed portions of the first transparent conductive layer 13 and the second transparent conductive layer 24 to form an electrode pattern, thereby obtaining the first electrode 211 and the second electrode 212. Simultaneously, the first metal layer 14 and the second metal layer 24, which are formed into a metal lead pattern, are superimposed on the first transparent conductive layer 13 and the second transparent conductive layer 23 in the lead region, respectively, to form a double-layer structure of first leads 221 and second leads 222. The first leads 221 and the second leads 222 are electrically connected to the first electrode 211 and the second electrode 212, respectively.

[0094] When fabricating a touch screen using the above method, the first metal layer 14, the second metal layer 24, the first transparent conductive layer 13, and the second transparent conductive layer 23 are directly etched to form the first electrode 211, the second electrode 212, and the first lead 221 and the second lead 222 electrically connected to the first electrode 211 and the second electrode 212. Therefore, there is no need to form the leads using silk screen printing, effectively simplifying the process and improving processing efficiency. Furthermore, the touch screen fabricated using the above method has a narrow bezel.

[0095] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A transparent conductive film comprising: A substrate comprising a first surface and a second surface disposed opposite to each other; forming a first hard coating layer, a first transparent conductive layer, and a first metal layer in sequence on the first surface; forming a second hard coating layer, a second transparent conductive layer, and a second metal layer in sequence on the second surface; It is characterized in that the first hard coating layer contains a plurality of particles to form a plurality of protrusions on the surface of the first metal layer, and the height Rz of the plurality of protrusions is in the range of 0.25um <Rz<0.5μm; There are gaps between the plurality of particles and the surface of the substrate; The size of the particle in a direction perpendicular to the first surface is larger than the size in a direction parallel to the first surface; the particle includes a solid area and a hollow area, the solid area is located at one end of the particle close to the substrate, and the hollow area is located at the other end of the particle.

2. The transparent conductive film according to claim 1, wherein The distribution density of the protrusions is 100 to 3000 per mm2.

3. The transparent conductive film according to claim 1, wherein The particles are made of the same material as the first hard coating layer.

4. The transparent conductive film according to any one of claims 1 to 3, wherein: The particles are in an elongated shape, and a size of the particles in a direction perpendicular to the first surface is larger than a size of the particles in a direction parallel to the first surface.

5. The transparent conductive film according to claim 4, wherein The particles are arranged perpendicularly relative to the first surface.

6. The transparent conductive film according to claim 4, wherein The center of gravity of the particle is located at one end of the particle close to the substrate, and the particle size of the particle is smaller than the thickness of the first hard coating layer.

7. A touch screen, characterized in that: The touch screen is made of the transparent conductive film described in any one of claims 1 to 6 above, and the touch screen includes a touch area and a lead area, and the first metal layer and the second metal layer are located in the lead area; the touch area includes a first electrode formed by etching the first transparent conductive layer, and a second electrode formed by etching the second transparent conductive layer; the lead area includes a first lead formed by etching the first metal layer and the first transparent conductive layer located in the lead area, and a second lead formed by etching the second metal layer and the second transparent conductive layer located in the lead area.

8. A method for preparing a touch screen, characterized in that: Including steps: Provided is a transparent conductive film according to any one of claims 1 to 6; Etching the first metal layer and the second metal layer to expose the first transparent conductive layer and the second transparent conductive layer in the touch area, and forming a metal lead pattern in the lead area; The first transparent conductive layer and the second transparent conductive layer are etched to form a first electrode and a second electrode in the touch area, and a transparent lead pattern in the lead area. The metal lead pattern and the transparent lead pattern together constitute electrode leads.

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