Transparent conductive film, touch screen and preparation method thereof

Abstract

The present invention relates to a transparent conductive film, comprising a first hard coating layer, a first transparent conductive layer and a first metal layer sequentially formed on the first surface of a substrate, and a second hard coating layer, a second transparent conductive layer and a second metal layer on the second surface of the substrate. The first hard coating layer and / or the second hard coating layer contains a plurality of particles to form a plurality of protrusions on the surface of the first metal layer and / or the second metal layer. The surface of the particles is provided with a plurality of strip-shaped grooves. When the transparent conductive film is rolled up, the plurality of protrusions can form point contact between two adjacent metal layers, thereby preventing adhesion. Moreover, since the surface of the particles is provided with a plurality of strip-shaped grooves, the surface area of ​​the particles is increased. Therefore, the contact area between the particles and the first hard coating layer and / or the second hard coating layer is increased, so the adhesion of the particles is increased, thereby effectively preventing the particles from falling off. In addition, the present invention also provides a touch screen and a preparation method thereof.

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 particles in existing conductive films are generally spherical or ellipsoidal, with relatively smooth surfaces. Consequently, the particles have limited adhesion to the hard coating layer. Forming a conductive layer and a metal layer on the hard coating layer containing the particles requires coating and drying steps, which can easily cause the particles with poor adhesion to fall off the hard coating layer, thereby compromising the anti-blocking properties of the conductive film. Summary of the Invention

[0005] Based on this, it is necessary to provide a transparent conductive film, a touch screen and a preparation method thereof that can effectively enhance the adhesion of particles in order to solve the problem that particles in the existing transparent conductive film with anti-adhesion function are easy to fall off.

[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 and / or the second hard coating layer contains a plurality of particles to form a plurality of protrusions on the surface of the first metal layer and / or the second metal layer;

[0011] Wherein, a plurality of strip-shaped grooves are provided on the surface of the particles.

[0012] Since the surface of the particles is provided with a plurality of strip-shaped grooves, the surface area of ​​the particles is increased. Therefore, the contact area between the particles and the first hard coating layer and / or the second hard coating layer is increased, thereby increasing the adhesion of the particles and effectively preventing the particles from falling off.

[0013] In one embodiment, the particles are made of the same material as the first hard coating layer and the second hard coating layer.

[0014] In other words, the particles share the same optical parameters as the first and second hard coatings (hereinafter collectively referred to as the hard coatings). Consequently, light propagation is less affected at the interface between the particles and the hard coatings, and the particles and hard coatings appear to be more integrated. When light passes through the hard coatings containing the particles, its propagation path is less distorted. Consequently, the transparent conductive film achieves anti-adhesion and anti-compression properties while also preventing adverse effects on its optical properties.

[0015] In one embodiment, both ends of the plurality of strip-shaped grooves are located on an axis passing through the particle.

[0016] The axis is a straight line passing through any point on the particle surface and the point farthest from that point. In this case, the multiple grooves share a common starting and ending points, maximizing the particle surface coverage. This helps maximize the particle's surface area while maintaining a constant particle volume.

[0017] In one embodiment, in the cross section of the particle, the inner wall profile of the strip-shaped groove is triangular.

[0018] The triangular grooves facilitate molding and can further increase the surface area of ​​the particles. Therefore, the strip grooves with triangular inner wall profiles can improve processing efficiency while further enhancing the adhesion of particles.

[0019] In one embodiment, the particles are in the shape of elongated strips, and the size of the particles in a direction perpendicular to the surface of the substrate is larger than the size in a direction parallel to the surface of the substrate.

[0020] 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.

[0021] In the present invention, the particles are elongated, and their dimensions in the direction perpendicular to the substrate surface (longitudinal direction) are larger than their dimensions in the direction parallel to the substrate 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.

[0022] In one embodiment, the particles are arranged perpendicularly relative to the surface of the substrate, and the strip-shaped grooves extend in a direction perpendicular to the surface of the substrate.

[0023] This further increases the particle's longitudinal to transverse dimension ratio, thereby reducing the particle's transverse dimension while maintaining the same protrusion height. Furthermore, the stripe-shaped grooves align with the particle's longitudinal direction. Therefore, the stripe-shaped grooves act as light pathways, further alleviating the particle's light-blocking effect and thus further reducing the haze of the transparent conductive film.

[0024] In one embodiment, the center of gravity of the particle is located at an end of the particle close to the substrate.

[0025] When preparing a transparent conductive film, a layer of fluid adhesive resin must first be applied to the 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. Finally, the adhesive resin is cured to obtain a hard coating containing the particles.

[0026] Because the particle's center of gravity is located at the end closest to the substrate, meaning it has an offset center of gravity, the particles naturally tilt under the influence of gravity during sedimentation, ultimately becoming fixed in the hard coating perpendicularly or approximately perpendicularly to the substrate surface. This simplifies the transparent conductive film fabrication process by allowing the particles to be positioned in a predetermined configuration without requiring additional manipulation.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] A method for preparing a touch screen comprises the following steps:

[0032] Providing a transparent conductive film as described in any one of the above preferred embodiments;

[0033] 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;

[0034] 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.

[0035] 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

[0036] Figure 1 Schematic diagram of the stacked structure of the transparent conductive film in a preferred embodiment of the present invention;

[0037] Figure 2 for Figure 1 An enlarged schematic diagram of a local area A in the transparent conductive film shown;

[0038] Figure 3 for Figure 1 Schematic diagram of the structure of particles in the transparent conductive film shown;

[0039] Figure 4 for Figure 3 Schematic diagram of the cross section of the particle along the BB direction;

[0040] Figure 5 is a schematic diagram of a stacked structure of a transparent conductive film in another embodiment of the present invention;

[0041] Figure 6 Schematic diagram of the stacked structure of the touch screen in a preferred embodiment of the present invention;

[0042] Figure 7 Schematic diagram of the process of manufacturing a touch screen in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0043] 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.

[0044] 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.

[0045] 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.

[0046] See also Figure 1 and Figure 2 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 .

[0047] The substrate 11 includes a first surface ( Figure 1 shown upper surface) and the second surface ( Figure 1 The 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] First metal layer 14 is formed on the surface of first transparent conductive layer 13. When the transparent conductive film of the present invention is used in a touch panel, for example, first metal layer 14 forms wiring outside the touch input area. Typical materials for first metal layer 15 are copper and silver, but any other metal with excellent conductivity may also be used. The thickness of first metal layer 14 is preferably 50 nm to 500 nm, more preferably 100 nm to 300 nm.

[0053] Furthermore, the second hard coating layer 22 , the second transparent conductive layer 23 and the second metal layer 24 have the same film structure, function and material composition as the first hard coating layer 12 , the first transparent conductive layer 13 and the first metal layer 14 , respectively, and thus are not described again herein.

[0054] In addition, the first hard coating layer 12 and / or the second hard coating layer 22 contain a plurality of particles 15 to form a plurality of protrusions 16 on the surface of the first metal layer 14 and / or the second metal layer 24. Figure 3 and Figure 4 The surface of the particle 15 is provided with a plurality of strip-shaped grooves 151. The plurality of strip-shaped grooves 151 are distributed along the circumference of the particle 15. Therefore, the surface area of ​​the particle 15 is increased, thereby increasing the contact area between the particle 15 and the first hard coating layer 12 and / or the second hard coating layer 22.

[0055] Specifically, the particles 15 can be randomly or uniformly distributed in the first hard coating layer 12 and / or the second hard coating layer 22. The particles 15 can be contained only in the first hard coating layer 12 or the second hard coating layer 12, thereby obtaining a transparent conductive film 10 having protrusions 16 formed on one side. The particles 15 can also be contained in both the first hard coating layer 12 and the second hard coating layer 12, thereby obtaining a transparent conductive film 10 having protrusions 16 formed on both sides.

[0056] Taking the formation of the protrusion 16 on the surface of the first metal layer 14 as an example for explanation:

[0057] The particles 15 protrude from the surface of the first hard coating layer 12, forming convex regions on the surface of the first hard coating layer 12. The regions of the first hard coating layer 12 not provided with the particles 15 form flat regions 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 layer 12, their surface shapes are identical to that of the first hard coating layer 12. Consequently, a plurality of protrusions 16 are formed in the regions of the first metal layer 14 corresponding to the particles 14.

[0058] Similarly, when the second hard coating layer 22 contains suspended particles 15 , a plurality of protrusions 16 may also be formed on the surface of the second metal layer 24 .

[0059] When a long strip of transparent conductive film 10 is manufactured using a roll-to-roll process, the particles 15 form a plurality of protrusions 16 on the surface of the first metal layer 14 and / or the second metal layer 24. Therefore, when the transparent conductive film 10 is rolled up, the plurality of protrusions 16 can form point contacts between adjacent metal layers, thereby preventing them from sticking or pressing against each other.

[0060] Furthermore, since the contact area between the particles 15 and the first hard coating layer 12 and / or the second hard coating layer 22 increases, the adhesion of the particles 15 increases, thereby effectively preventing the particles 15 from falling off.

[0061] In this embodiment, the first hard coating layer 12 and the second hard coating layer 22 both contain particles 15 , so that a plurality of protrusions 16 are formed on the surfaces of the first metal layer 14 and the second metal layer 24 .

[0062] That is, multiple protrusions 16 are formed on both sides of the obtained transparent conductive film 10. Therefore, when the transparent conductive film 10 is rolled up, the number of point contacts between two adjacent metal layers increases, thereby improving the anti-sticking and anti-compression effects.

[0063] See also Figure 5 In another embodiment, either the first hard coating layer 12 or the second hard coating layer 22 contains particles 15 , so that a plurality of protrusions 16 are formed on the surface of the first metal layer 14 or the second metal layer 14 .

[0064] In other words, the resulting transparent conductive film 1 has multiple protrusions 16 formed on only one side. Therefore, while providing anti-adhesion and anti-compression properties, it also prevents the shadows of the two layers of particles 15 from overlapping, thereby reducing haze and improving the optical effect of the transparent conductive film 10.

[0065] In this embodiment, the particles 15 are made of the same material as the first hard coating layer 12 and the second hard coating layer 22 .

[0066] Because particles 15 are made of the same material as the first hard coating layer 12 and the second hard coating layer 22 (hereinafter collectively referred to as the hard coating layers), their optical parameters are also identical. Therefore, light propagation is minimally affected at the interface between particles 15 and the hard coating layers, and particles 15 and the hard coating layers appear to be more integrated. When light passes through the hard coating layers containing particles 15, its propagation path is less distorted. Therefore, transparent conductive film 10 achieves anti-adhesion and anti-compression properties while also preventing adverse effects on its optical properties.

[0067] Please refer again Figure 3 and Figure 4 In this embodiment, both ends of the plurality of strip-shaped grooves 151 are located on the axis passing through the particle 15 .

[0068] Specifically, the axis is a straight line passing through any point on the surface of the particle 15 and the point farthest from that point. In this case, the plurality of strip-shaped grooves 151 have a common starting point and end point, thereby allowing the surface of the particle 15 to be covered to the greatest extent possible by the strip-shaped grooves 151. This facilitates maximizing the surface area of ​​the particle 15 while maintaining the same volume.

[0069] Furthermore, in this embodiment, in the cross section of the particle 15 perpendicular to the axis, the inner wall profile of the strip-shaped groove 151 is triangular.

[0070] The triangular groove facilitates molding and can further increase the surface area of ​​the particles 15. Therefore, the strip-shaped groove 151 with a triangular inner wall profile can improve processing efficiency while further enhancing the adhesion of the particles 15.

[0071] In this embodiment, the particles 15 are in the shape of elongated strips, and the size of the particles 15 in a direction perpendicular to the surface of the substrate 11 is larger than the size in a direction parallel to the surface of the substrate.

[0072] 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.

[0073] In the present invention, particles 15 are elongated. When particles 15 are positioned perpendicular or approximately perpendicular to the surface of substrate 11, the size of particles 15 in the direction perpendicular to the surface of substrate 11 (longitudinal dimension) is greater than the size in the direction parallel to the surface of substrate 11 (lateral dimension). In other words, the longitudinal and lateral dimensions of particles 15 are relatively large. Therefore, even if the height of protrusions 16 increases, the lateral dimension of particles 15 can be maintained within a relatively small range, thereby improving the anti-blocking effect of transparent conductive film 10 while effectively reducing its haze.

[0074] Furthermore, in this embodiment, the particles 15 are disposed perpendicularly relative to the surface of the substrate 11 , and the strip-shaped grooves 151 extend in a direction perpendicular to the surface of the substrate 11 .

[0075] Specifically, the strip-shaped grooves 151 extend in the same direction as the elongated particles 15 and are both perpendicular to the surface of the substrate 11. This maximizes the ratio of the longitudinal to transverse dimensions of the particles 15, further reducing the transverse dimensions of the particles 15 while maintaining the same height as the protrusions 16. Furthermore, because the strip-shaped grooves 151 extend longitudinally, they serve as pathways for light, further alleviating the light-blocking effect of the particles 15 and thereby further reducing the haze of the transparent conductive film 10.

[0076] 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 .

[0077] When preparing the transparent conductive film 10, a layer of fluid adhesive resin is first applied to the surface of the substrate 11. Before the adhesive resin solidifies, prefabricated particles 15 are sprayed on it. 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 hard coating layer containing the particles.

[0078] Because the center of gravity of the particles 15 is located at the end closest to the substrate 11, in other words, the particles 15 have an offset center of gravity. Therefore, similar to the principle of a tumbler, the particles 15 naturally settle and then flip over under the action of gravity, ultimately becoming fixed in the hard coating layer in a direction perpendicular or approximately perpendicular to the surface of the substrate 11. Since the particles 15 can be arranged in a predetermined configuration without requiring any additional steps, the preparation process of the transparent conductive film 10 can be simplified.

[0079] In this embodiment, the particle 15 includes a solid region and a hollow region. The solid region is located at one end of the particle close to the substrate 11 , and the hollow region is located at the other end of the particle 15 .

[0080] Specifically, by providing solid and hollow regions, the center of gravity of the particle 15 can be offset. Furthermore, there are various methods for forming the hollow region on the particle 15, such as air blowing and 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.

[0081] In order to achieve better anti-adhesion and anti-compression effects, there are corresponding requirements for the surface roughness of the first metal layer 14 and the second metal layer 24 and the density of the protrusions 16 .

[0082] In this embodiment, the arithmetic mean roughness Ra of the first metal layer 14 and the second metal layer 24 is 0.0025 to 0.025 μm. In addition, the distribution density of the protrusions 16 on the surface of the first metal layer 14 is 100 to 3000 per mm. 2 .

[0083] 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 roughness and density ranges, the transparent conductive film 10 can achieve a good balance between anti-blocking and optical performance.

[0084] The surface arithmetic average roughness Ra and distribution density of the first metal layer 14 and the second metal layer 24 can be changed by adjusting the shape, size and content of the particles 15 .

[0085] Furthermore, in this embodiment, in a direction perpendicular to the surface of the first metal layer 14 and / or the second metal layer 24 , the height of the plurality of protrusions 16 is 0.1-0.5 μm.

[0086] The height of the protrusion 16 refers to the height of the protrusion 16 protruding from the surface of the first metal layer 14 and / or the second metal layer 24. Due to the small size of the particles 15, it is difficult to accurately control the height of each protrusion 16. Therefore, it is sufficient to control the height of the protrusion 16 within the above-mentioned height range. It should be noted that in actual production, due to the difficulty in accurately controlling the height of each particle 15, it is inevitable that the height of the protrusion 16 formed by a very small number of particles 15 will be outside the above-mentioned range. However, the impact of this portion of protrusion 16 can be ignored.

[0087] Generally, the higher the height of the protrusions 16, the better the anti-blocking effect. However, as the height increases, the size of the particles 15 must also increase, which in turn increases the haze value of the transparent conductive film 10. Once this haze reaches a certain level, it will seriously affect the optical performance of the transparent conductive film 10. Within the aforementioned height range, the transparent conductive film 10 can achieve a good balance between anti-blocking and optical performance. The height of the protrusions 16 can be adjusted by adjusting the size of the particles 15.

[0088] In the transparent conductive film 10, the particles 15 form a plurality of protrusions 16 on the surface of the first metal layer 14 and / or the second metal layer 24. Therefore, when the transparent conductive film 10 is rolled up, the plurality of protrusions 16 create point contact between adjacent metal layers, preventing adhesion. Furthermore, the surface of the particles 16 is provided with a plurality of strip-shaped grooves 151, increasing the surface area of ​​the particles 15. This increases the contact area between the particles 15 and the first hard coating layer 12 and / or the second hard coating layer 22, thereby enhancing the adhesion of the particles 15 and effectively preventing the particles 15 from falling off.

[0089] In addition, the present invention also provides a touch screen. Figure 6The touch screen 200 in the preferred embodiment of the present invention is made of the transparent conductive film 10 in the above embodiment.

[0090] The touch screen 200 includes a touch area 210 and a lead area 220. Specifically, the touch area 210 is located in the center of the touch screen 200, while the lead area 220 is disposed around the touch area 210. The first metal layer 14 and the second metal layer 24 are located in the lead area 220.

[0091] The touch area 210 includes a first electrode 211 and a second electrode 212. The first electrode 211 is etched from the first transparent conductive layer 13, while the second electrode 212 is etched from the second transparent conductive layer 23. The first and second electrodes 211, 212 are etched into an electrode pattern. Specifically, the electrode pattern is generally long and intersecting in a grid pattern. The opposing first and second electrodes 211, 212 form the two poles of a capacitor structure.

[0092] The lead region 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 region 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 region 220. The first lead 221 and the second lead 222 have a double-layer structure, thereby achieving electrical connection with the first electrode 211 and the second electrode 212.

[0093] In the aforementioned touch screen, first leads 221 and second leads 222 are formed by directly etching 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 silk screen printing is not required, the width of the electrode leads formed directly by the photolithography process can be further reduced, resulting in a narrow bezel on the touch screen.

[0094] Please also refer to Figure 7 The present invention also provides a method for preparing a touch screen, which includes steps S310 to S330:

[0095] Step S310: providing a transparent conductive film.

[0096] Specifically, the transparent conductive film is the transparent conductive film 100 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.

[0097] 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

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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; Characterized in that the first hard coating layer and / or the second hard coating layer contains a plurality of particles to form a plurality of protrusions on the surface of the first metal layer and / or the second metal layer, and the height of the plurality of protrusions is 0.1 to 0.5 μm; The surface of the particle is provided with a plurality of strip-shaped grooves distributed along the circumference of the particle, the center of gravity of the particle is located at one end of the particle close to the substrate, and 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 particles are made of the same material as the first hard coating layer and the second hard coating layer.

3. The transparent conductive film according to claim 1, wherein Both ends of the plurality of strip-shaped grooves are located on an axis passing through the particle.

4. The transparent conductive film according to claim 3, wherein On a cross section of the particle perpendicular to the axis, the inner wall profile of the strip-shaped groove is triangular.

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

6. The transparent conductive film according to claim 5, wherein The particles are arranged perpendicularly relative to the surface of the substrate, and the strip-shaped grooves extend in a direction perpendicular to the surface of the substrate.

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; The first metal layer and the second metal layer are etched to expose the first transparent conductive layer and the second transparent conductive layer in the touch area. Conductive layer, and forming a metal lead pattern located 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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