Ultra-thin composite transparent conductive film and preparation method thereof

Abstract

The present invention discloses an ultrathin composite transparent conductive film, comprising a transparent substrate, one surface of which is provided with a first UV adhesive layer, a second UV adhesive layer, and a third UV adhesive layer. The first UV adhesive layer is patterned, embossed, cured, and filled with a conductive material to form a grid-like groove in the first conductive layer and lead grooves in a first lead region. The depth of the grid-like grooves in the first conductive layer and the lead grooves in the first lead region are less than the thickness of the first UV adhesive layer. A second UV adhesive layer is provided on the surface of the first UV adhesive layer, and the second UV adhesive layer serves as a reinforced insulating support layer. The third UV adhesive layer is patterned, embossed, cured, and filled with a conductive material to form a grid-like groove in the second conductive layer and lead grooves in the second lead region. The depth of the grid-like grooves in the second conductive layer and the lead grooves in the second lead region is no greater than the thickness of the third UV adhesive layer. The conductive film of the present invention has a simple structure, a simplified and stable process, and a wide range of applications.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive films, in particular to an ultra-thin composite transparent conductive film and a preparation method thereof, as well as products using the conductive film. Background Art

[0002] Transparent conductive films, characterized by excellent electrical conductivity and high transmittance in the visible light band, have been widely used in fields such as flat-panel displays, photovoltaic devices, touch panels, and electromagnetic shielding, and have a broad market potential. Due to the various drawbacks of ITO, flexible, low-resistance metal mesh-based transparent conductive films are playing an increasingly important role.

[0003] The transparent conductive film in the prior art refers to "a conductive thin film that can realize some specific electronic functions". Generally, a conductive layer is made on a transparent substrate, which usually includes a transparent substrate layer and a related metal buried layer; the surface of the transparent substrate layer has a patterned and interconnected groove network, and the conductive material is filled in the groove network to form a conductive film.

[0004] Existing transparent conductive films form a single conductive layer on the surface of a substrate. This conductive structure only has the conductive function of a general-purpose conductive film, but lacks the circuit functions of a proprietary sensor. For example, for a mutual capacitance touch sensor with upper and lower electrodes, post-processing such as adding a lead area is required. The two layers of circuit film, after post-processing, must be combined using optical bonding adhesive to form a touch sensor.

[0005] Existing methods for fabricating transparent conductive films use microfabrication techniques such as photolithography to create microstructures, then use embossing techniques to form grooves, which are then filled with conductive ink and sintered. This single transparent conductive film produced using these steps fails to account for material deformation during the manufacturing process, leading to dimensional distortion in the capacitor electrode pattern. This leads to low yields and high costs in actual mass production.

[0006] The existing technology for producing conductive films usually has the following technical problems: the production process is complicated, and the product quality cannot be stably controlled, resulting in a low yield rate. In particular, the current capacitive screen basically adopts a process of laminating two transparent conductive films to each other, and the product thickness is limited, which does not conform to the existing trend of touch screens to develop towards ultra-light and ultra-thin, and the cost is high. In the future, electronic devices will gradually develop towards curved design and flexible screen design, but the touch module made by laminating two transparent conductive films to each other has poor bending resistance.

[0007] To this end, the present invention proposes a functional transparent conductive film with a multi-layer composite structure and a manufacturing method, which solves the defects of existing product structures and manufacturing methods. Summary of the Invention

[0008] The purpose of the present invention is to overcome the shortcomings of the existing technology, solve the problems existing in the existing technology, and provide an ultra-thin composite transparent conductive film. This ultra-thin composite transparent conductive film has a simple structure, simplified process, stable process, reduced cost, and a wide range of application scenarios.

[0009] To solve the above technical problems, the present invention provides the following technical solutions: an ultra-thin composite transparent conductive film, comprising a transparent substrate:

[0010] One side of the transparent substrate is provided with a first UV adhesive layer, a second UV adhesive layer, and a third UV adhesive layer;

[0011] The first UV adhesive layer is a first layer of UV curable adhesive coated on the surface of the transparent substrate. The first UV adhesive layer is patterned and embossed and cured to form the grid-shaped grooves of the first conductive layer and the lead grooves of the first lead area. The grid-shaped grooves of the first conductive layer and the lead grooves of the first lead area are filled with a conductive material. The depth of the grid-shaped grooves of the first conductive layer and the lead grooves of the first lead area are less than the thickness of the first UV adhesive layer.

[0012] A second UV adhesive layer is provided on the surface of the first UV adhesive layer, and the second UV adhesive layer serves as a reinforced insulating support layer;

[0013] A third UV adhesive layer is provided on the surface of the second UV adhesive layer. The surface of the third UV adhesive layer is patterned and cured to form grid-shaped grooves of the second conductive layer and lead grooves of the second lead area. The grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area are filled with conductive material. The depth of the grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area is not greater than the thickness of the third UV adhesive layer.

[0014] As a preferred embodiment of the ultra-thin composite transparent conductive film of the present invention: the first UV adhesive layer is patterned and embossed and cured to form grid-like grooves of the first conductive layer, lead grooves of the first lead area, and alignment pattern grooves of the first alignment mark; the grid-like grooves of the first conductive layer, the lead grooves of the first lead area, and the alignment pattern grooves of the first alignment mark are all filled with conductive material; and the depth of the grid-like grooves of the first conductive layer, the lead grooves of the first lead area, and the alignment pattern grooves of the first alignment mark are all less than the thickness of the first UV adhesive layer;

[0015] The surface of the third UV adhesive layer is patterned and cured to form grid-like grooves of the second conductive layer, lead grooves of the second lead area, and alignment pattern grooves of the second alignment mark. The grid-like grooves of the second conductive layer, the lead grooves of the second lead area, and the alignment pattern grooves of the second alignment mark are all filled with conductive material. The depth of the grid-like grooves of the second conductive layer, the lead grooves of the second lead area, and the alignment pattern grooves of the second alignment mark is no greater than the thickness of the third UV adhesive layer.

[0016] The patterns of the first alignment mark and the second alignment mark are either retained or cut out in the transparent conductive film product.

[0017] As a preferred solution of the ultra-thin composite transparent conductive film of the present invention: the thickness of the second UV adhesive layer is 1 to 10 microns.

[0018] As a preferred solution of the ultra-thin composite transparent conductive film of the present invention: the second UV adhesive layer and the third UV adhesive layer are made of different materials, and the first UV adhesive layer and the third UV adhesive layer are made of the same or different materials.

[0019] As a preferred solution of the ultra-thin composite transparent conductive film described in the present invention: the electrical connection area of ​​the first lead area is not coated with the second layer of UV curing glue, and the electrical connection area of ​​the second lead area of ​​the third UV glue layer does not overlap with the electrical connection area of ​​the first lead area of ​​the first UV glue layer.

[0020] As a preferred embodiment of the ultra-thin composite transparent conductive film of the present invention: an adhesion-enhancing layer is coated or treated between the transparent substrate and the first UV adhesive layer;

[0021] And / or, an adhesion-enhancing layer is coated between the first UV adhesive layer and the second UV adhesive layer or an adhesion-enhancing treatment is performed;

[0022] And / or, an adhesion-enhancing layer is coated between the second UV adhesive layer and the third UV adhesive layer or an adhesion-enhancing treatment is performed.

[0023] As a preferred solution of the ultra-thin composite transparent conductive film described in the present invention: the second UV adhesive layer is a composite layer formed by coating UV curing adhesive multiple times on the surface of the first UV adhesive layer, and the surface of the electrical connection area of ​​the first lead area is not covered by the second UV adhesive layer.

[0024] As a preferred solution of the ultra-thin composite transparent conductive film described in the present invention: the grid-shaped grooves of the first conductive layer and the second conductive layer and the lead grooves of the first lead area and the second lead area are filled with nano-silver paste or nano-copper paste or graphene material or nano-silver wire or carbon nanotube material.

[0025] As a preferred embodiment of the ultra-thin composite transparent conductive film described in the present invention: a protective layer is provided on the upper surface of the third UV adhesive layer, and the protective layer is a polymer layer. The first UV adhesive layer, the second UV adhesive layer, the third UV adhesive layer, the protective layer and the transparent substrate together form a composite transparent conductive film, and the electrical connection area of ​​the second lead area of ​​the third UV adhesive layer does not overlap with the electrical connection area of ​​the first lead area of ​​the first UV adhesive layer.

[0026] A method for preparing an ultrathin composite transparent conductive film, characterized by comprising the following main steps:

[0027] Step 1: A first layer of UV curable adhesive is coated on the surface of the transparent substrate, and a pattern is embossed and cured on the first layer of UV curable adhesive to form a grid-like groove of the first conductive layer, a lead groove of the first lead area, and a pattern groove of the first alignment mark, so that the depth of the grid-like groove and the lead groove is less than the thickness of the first UV adhesive layer;

[0028] Step 2: Filling the grid-shaped grooves of the first conductive layer, the lead grooves of the first lead area, and the pattern grooves of the first alignment mark with a conductive material to form a first UV adhesive layer;

[0029] Step 3: Then selectively coating a second layer of UV curing adhesive on the surface of the first UV adhesive layer to form a second UV adhesive layer, and the electrical connection area of ​​the first lead area is not coated with the second layer of UV curing adhesive;

[0030] Step 4: Coating a third layer of UV curing adhesive on the surface of the second UV adhesive layer, performing patterned alignment embossing and curing on the third layer of UV curing adhesive to form a grid-shaped groove with a second conductive layer, a lead groove of the second lead area, and a patterned groove of the second alignment mark, wherein the depth of the grid-shaped groove of the second conductive layer and the lead groove of the second lead area is no greater than the thickness of the third UV adhesive layer, and the electrical connection area of ​​the second lead area does not overlap with the electrical connection area of ​​the first lead area;

[0031] Step five: filling the grid-shaped grooves of the second conductive layer, the lead grooves of the second lead area, and the pattern grooves of the second alignment mark with conductive material.

[0032] An ultra-thin composite transparent conductive film structure comprises a transparent substrate, wherein one side of the transparent substrate is provided with a first UV adhesive layer, a second UV adhesive layer, and a third UV adhesive layer;

[0033] The first UV adhesive layer is a first layer of UV curable adhesive coated on the surface of the transparent substrate. The first layer of UV curable adhesive is patterned and embossed and cured to form grid-like grooves in the first conductive layer. The grid-like grooves in the first conductive layer are filled with a conductive material. The depth of the grid-like grooves is less than the thickness of the first UV adhesive layer.

[0034] The second UV adhesive layer is a second layer of UV curable adhesive provided on the surface of the first UV adhesive layer, and is cured to form a second UV adhesive layer serving as a reinforced insulating support layer;

[0035] The third UV adhesive layer is a third layer of UV curable adhesive arranged on the surface of the second UV adhesive layer. The third layer of UV curable adhesive is graphically embossed and cured to form a grid-shaped groove with a second conductive layer. The grid-shaped groove of the second conductive layer is filled with a conductive material. The depth of the grid-shaped groove is no greater than the thickness of the third UV adhesive layer.

[0036] A touch display panel comprises a display device and the ultra-thin composite transparent conductive film according to any one of claims 1 to 9.

[0037] A large-size all-in-one touch-screen device comprises a display device, a CPU processor, and a power supply. The display device comprises a touch panel, and the touch panel comprises the aforementioned ultra-thin composite transparent conductive film.

[0038] A composite transparent conductive film comprises a transparent substrate: one side of the transparent substrate is patterned and embossed to form grid-like grooves of a first conductive layer and lead grooves of a first lead area, wherein the grid-like grooves of the first conductive layer and the lead grooves of the first lead area are filled with a conductive material;

[0039] A second UV adhesive layer is provided on one side of the transparent substrate forming the first conductive layer, the second UV adhesive layer serving as a reinforced insulating support layer, and the electrical connection area of ​​the first lead area is not coated with the second UV adhesive layer;

[0040] A third UV adhesive layer is provided on the surface of the second UV adhesive layer. The surface of the third UV adhesive layer is patterned and cured to form grid-shaped grooves of the second conductive layer and lead grooves of the second lead area. The grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area are filled with conductive material. The depth of the grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area is no greater than the thickness of the third UV adhesive layer. The electrical connection area of ​​the second lead area does not overlap with the electrical connection area of ​​the first lead area.

[0041] The applicant has long been engaged in using nanoimprint technology to create grooves for embedding conductive metal particles and a light-transmitting grid on transparent substrates. By designing the groove width and depth, as well as the proportion of the grooves in the overall transparent conductive film, the inventor has achieved a transparent conductive film with high light transmittance and good conductivity. Based on previous technical experience, the inventor tried various solutions before arriving at the technical solution of this patent, but none of them were effective.

[0042] One of the solutions developed by the inventors is to directly dispose a double-layer or multi-layer patterned transparent conductive film structure on one surface of a transparent substrate. Although this technical solution is theoretically good, as long as the thickness of the upper transparent adhesive layer is controlled to be greater than the depth of the upper conductive layer, the two conductive layers can be insulated from each other. However, in practice, the inventors conducted extensive experiments and found that the yield of this technical solution is too low, making it unfeasible for large-scale mass production. For details, please refer to the experimental data and analysis in the specific examples section.

[0043] The inventors arrived at the technical solution of this patent after many improvements and continuous attempts. The technical solution of this patent has at least the following beneficial technical effects:

[0044] 1. The ultra-thin composite transparent conductive film of the present invention creatively uses a separately provided reinforced insulating support layer to isolate the first conductive layer from the second conductive layer. The second conductive layer is provided in the third UV adhesive layer, and the third UV adhesive layer is provided on the second UV adhesive layer (serving as the reinforced insulating support layer) that has been printed or coated and cured. This can greatly improve the insulation effect between the first conductive layer and the second conductive layer, and effectively prevent the short circuit problem of the conductive layer.

[0045] According to the present invention Figure 2 In the research and development reference example, a double-layer patterned transparent conductive film structure is directly set on a transparent substrate. It is found that the yield rate is very low and there are a large number of short-circuit problems in the conductive layer. The cause of this problem may be various factors such as cracking during high-temperature treatment, solvent volatilization, and defects formed in the polymer. The deeper reason is that the processing of polymer materials involved in the patented products and processes is an interdisciplinary technology. The processing of polymer materials involves the intersection of multiple disciplines such as polymer chemistry, chemical engineering, polymer physics, engineering thermal physics, and process control. The various properties of polymer materials are usually closely related to their chemical structure, and the chemical structure can be influenced by the processing technology of polymer materials. Therefore, many seemingly subtle changes in the processing technology often have unexpected changes in the output quality control of polymer materials.

[0046] The second UV adhesive layer set separately in this patent can effectively solve the above problems and produce better technical effects. Figure 2 In the research and development reference example, a second conductive layer is directly provided on the first conductive layer of the first UV adhesive layer. However, due to various factors in the processing of polymer materials, the conductive material may penetrate through the conductive material, thereby easily causing a short circuit. The yield is too low to be actually mass-produced.

[0047] This patent sets up a separate reinforced insulating support layer, which plays a certain smoothing role, and then prints a third UV adhesive layer on the cured second UV adhesive layer. When the surface of the third UV adhesive layer is patterned and filled with conductive material to make the second conductive layer, since the first conductive layer and the second conductive layer are separated by not only the third UV adhesive layer but also the cured second UV adhesive layer, the problem of interlayer short circuit between the two conductive layers is unlikely to occur, thereby greatly improving the product yield.

[0048] According to experimental data, it can be seen that providing a separate reinforced insulating support layer is more effective than simply increasing the thickness of the third UV adhesive layer.

[0049] At the same time, the technical solution of this patent can also make the first UV adhesive layer and the third UV adhesive layer appropriately thinner while controlling the original thickness of the conductive film product to remain unchanged or thinner, leaving thickness space for the separately set second UV adhesive layer for insulation isolation, so that the entire electronic product is thinner.

[0050] 2. The reinforced insulating support layer added in this patent not only plays a role in strengthening insulation, but also forms a composite layer structure with the upper and lower conductive layers, which increases the bending resistance of the conductive film, further improves the stability of the product, and expands the application scenarios of the product, making it suitable for multi-touch needs such as flexible screens.

[0051] 3. The present invention also provides a method for producing the ultra-thin composite transparent conductive film, which can prepare the ultra-thin composite transparent conductive film on a large scale, simplify the preparation process, improve the yield, enhance the product production efficiency, and reduce the product cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0053] Figure 1 is a schematic diagram of the three-dimensional structure of the ultra-thin composite transparent conductive film in the first embodiment of the present invention;

[0054] Figure 2 is a schematic structural diagram of a transparent conductive film developed by the inventor as a reference example;

[0055] Figure 3 is a schematic cross-sectional structure diagram of the ultra-thin composite transparent conductive film in the first embodiment of the present invention;

[0056] Figure 4 is a schematic structural diagram of an ultra-thin composite transparent conductive film according to a second embodiment of the present invention;

[0057] Figure 5 is a graph showing the thickness and yield of the second UV adhesive layer in the present invention;

[0058] Figure 6 This is a graph showing the relationship between the thickness and yield of the third UV adhesive layer when the second UV adhesive layer is not set.

[0059] Figure 7 A schematic diagram showing the electrical connection area of ​​the first conductive layer lead area and the electrical connection area of ​​the second conductive layer lead area is shown. DETAILED DESCRIPTION

[0060] The following is combined with Figure 1-7 The technical solution of the present invention is described in detail in the following embodiments: 1. a transparent substrate; 2. a first UV adhesive layer; 3. a first conductive layer; 4. a second UV adhesive layer (a reinforced insulating support layer); 5. a third UV adhesive layer; 6. a second conductive layer; a protective layer (not shown in the figure, which can enhance its wear resistance, prevent metal oxidation or sulfide, etc.); 7. an electrical connection area of ​​the first lead area; 8. an electrical connection area of ​​the second lead area.

[0061] The terms "first UV adhesive layer", "second UV adhesive layer", and "third UV adhesive layer" in this patent are used to distinguish the various layer structures, and do not mean that the layer structure only contains UV adhesive. For example, the first and third UV adhesive layers include conductive structures according to their structural descriptions and drawings.

[0062] like Figure 1 As shown, this embodiment discloses an ultra-thin composite transparent conductive film, including a transparent substrate 1, on which a first UV adhesive layer 2 is provided, and the first conductive layer 3 is composed of a conductive material patterned and embossed in a plurality of grid grooves on the first UV adhesive layer 2; a third UV adhesive layer 5 is provided on the transparent reinforced insulating support layer 4, and the second conductive layer 6 is composed of a conductive material patterned and embossed in a plurality of grid grooves on the third UV adhesive layer 5.

[0063] It should be noted that the third UV adhesive layer containing the second conductive layer is arranged on the second UV adhesive layer (reinforced insulating support layer) cured after embossing, which can greatly improve the insulation strength between the first conductive layer and the second conductive layer and avoid the problem of conductive layer penetration. Figure 3 As shown, after the third UV adhesive layer is printed on the cured transparent reinforced insulating support layer, and the conductive material is filled after the third UV adhesive layer is cured to form the second conductive layer, the problem of interlayer short circuit is unlikely to occur, thereby greatly improving the product yield.

[0064] The transparent substrate is a polymer layer commonly used in conductive films. It should be noted that the materials of the first UV adhesive layer, the third UV adhesive layer and the second UV adhesive layer (reinforced insulating support layer) can be UV curing adhesives or thermosetting coatings, preferably UV curing adhesives. The surfaces of the first UV adhesive layer and the third UV adhesive layer are as smooth as possible after curing, for example, the friction coefficient is between 0.1 and 0.4, which is convenient for filling the conductive material by scraping. The second UV adhesive layer, that is, the adhesive layer of the reinforced insulating support layer, has a certain degree of roughness after curing, and the friction coefficient is preferably between 0.4 and 1.0, so that the reinforced insulating support layer has sufficient adhesion and increases the adhesion between the first UV adhesive layer and the third UV adhesive layer.

[0065] Each layer, for example, the transparent substrate, the first UV adhesive layer, the second UV adhesive layer and the third UV adhesive layer can be subjected to a tackifying treatment or coated with an tackifying coating according to conventional techniques. Conventional treatment of the tackifying layer itself cannot play a role in strengthening insulation and support. If the first UV adhesive layer, the third UV adhesive layer and the second UV adhesive layer (reinforced insulating support layer) all use the same UV curing adhesive, a tackifying treatment or a tackifying layer can be adopted for better bonding. The main materials of the conventionally used tackifying layer can be polyacetylene, polyaniline, polythiophene, graphene, polyethylene terephthalate, polyurethane, etc., which are usually coated on the surface of the substrate to achieve the effect of bonding with the upper structure, and the coating thickness ranges from 10 to 100 nm.

[0066] In addition to selecting PET, PI polyimide and other materials for transparent base materials according to different application scenarios and needs, in order to strengthen the insulation between the conductive layers, the preferred thickness of the strengthened insulating support layer is 5 to 10 microns. After embossing and curing, the surface is relatively flat and there will be no uneven thickness.

[0067] This patent strengthens the insulation and support function of the insulating support layer, so that the product yield can reach more than 90%. For details, please refer to Figure 2 , Figure 3 , Figure 5 , Figure 6 , and the following table explains.

[0068] The environmental test was conducted under the following conditions: temperature 85°C, humidity 85% RH, duration 240 hours, with power applied. Test method and key steps: 1. Collect test samples; 2. Inspect appearance and confirm functionality before testing; 3. Place in the test chamber; test conditions: temperature 85°C, humidity 85% RH, duration 240 hours, with power applied; 4. Remove the product after meeting test conditions; 5. After the product has rested for 24 hours, inspect appearance and conduct functional tests; 6. At the conclusion of the test, record the data as shown in the table below.

[0069]

[0070] The factors affecting the production yield of the aforementioned products are mainly the product structure. Products without a reinforced insulating support layer have a short circuit phenomenon between the upper and lower wires, while products with a reinforced insulating support layer (the solution of this patent) do not have this undesirable phenomenon.

[0071] For a structure without a reinforced insulating support layer, that is, a structure in which a double-layer patterned transparent conductive film is directly provided on a transparent substrate, such as Figure 2 The figure shows a research and development reference example developed by the inventors. In this conductive film structure, the transparent polymer layer may contain numerous tiny defects due to cracking during high-temperature processing, solvent volatilization, and defects in the polymer. The conductive material in the upper conductive layer can easily penetrate through these defects to the lower conductive layer, causing a short circuit between the two layers. This short circuit problem leads to product instability and a very high defect rate, making it impossible to achieve true industrial-scale production, especially when manufacturing large-scale conductive films.

[0072] Although the inventors have tried to increase the thickness of the upper transparent adhesive layer as much as possible to prevent problems such as short circuits between the upper conductive layer and the lower conductive layer, they found that the effect of improving product stability and yield is very limited. Figure 6 As shown, the bending resistance is not good either.

[0073] See Figure 3 and Figure 5 , where the thickness of the third UV adhesive layer is 8 microns, and the depth of the grid-like grooves embossed on the third UV adhesive layer is 5 microns. As can be seen from the figure, when the thickness of the reinforced insulating support layer, i.e., the second UV adhesive layer, is 5 microns or greater, the yield rate is close to 100%. It should be noted that the yield rate mentioned here refers to the yield rate of the interlayer short circuit test between the first conductive layer and the second conductive layer after the reinforced insulating support layer is added. The higher the yield rate, the lower the probability of interlayer short circuit.

[0074] Furthermore, the material of the second UV adhesive layer, which serves as the reinforced insulating support layer, can be different from that of the third UV adhesive layer. UV adhesive layers of different materials can be easily bonded together, or the refractive index difference between the reinforced insulating support layer and the third UV adhesive layer can be less than 0.3. In this way, two materials with the same or similar refractive index will not or will barely reduce the light transmittance of the product. The grid grooves of the first and third UV adhesive layers are formed using a patterned embossing technique. The conductive material can be a metallic conductive material or a non-metallic conductive material, preferably a conductive material such as silver, copper, or graphene.

[0075] Preferably, the thickness of the first UV adhesive layer is 8-12 microns, the thickness of the first conductive layer is 4-5 microns; the thickness of the third UV adhesive layer is 8-12 microns, the thickness of the second conductive layer is 4-5 microns; the thickness of the reinforced insulating support layer is 5-10 microns.

[0076] In order to realize the multi-touch function, in addition to the conductive layer, the two transparent adhesive layers are also provided with a lead area that connects the conductive layer to the external data processing device. The lead area is distributed on at least one side of the outer periphery of the conductive layer, and the electrical connection area of ​​the lead area is shown in FIG. Figure 7 The lead area is an area formed by the convergence of multiple leads connected to the conductive layer.

[0077] A first conductive layer and a first lead region are provided on the first UV adhesive layer. The first lead region is an area formed by the convergence of multiple leads connected to the first conductive layer. A second conductive layer and a second lead region are provided on the third UV adhesive layer. The second lead region is an area formed by the convergence of multiple leads connected to the second conductive layer. The first UV adhesive layer is patterned and cured to form a grid of grooves in the first conductive layer, lead grooves in the first lead region, and alignment grooves for the first alignment mark. The grid of grooves in the first conductive layer, the lead grooves in the first lead region, and the alignment grooves for the first alignment mark are all filled with a conductive material. The surface of the third UV adhesive layer is patterned and cured to form a grid of grooves in the second conductive layer, the lead grooves in the second lead region, and the alignment grooves for the second alignment mark. The grid of grooves in the second conductive layer, the lead grooves in the second lead region, and the alignment grooves for the second alignment mark are all filled with a conductive material. The patterns of the first alignment mark and the second alignment mark may be retained or cut out in the transparent conductive film product. The electrical connection area of ​​the first lead area is not coated with the second layer of UV curing glue, and the electrical connection area of ​​the second lead area of ​​the third UV glue layer does not overlap with the electrical connection area of ​​the first lead area of ​​the first UV glue layer.

[0078] Furthermore, according to the requirements of different applications, the upper surface of the third UV adhesive layer described in this patent can be further provided with a reinforced insulating support layer, and then a polymer layer is provided on the reinforced insulating support layer. The polymer layer is patterned and embossed to form a grid-like groove, and the grid-like groove is filled with a conductive material to form a third conductive layer. The third conductive layer can be connected to the casing or grounded, thereby serving as an electromagnetic shielding layer.

[0079] Furthermore, the third conductive layer can also be connected to an external device and then connected to current to make it a heating layer, so that the entire touch product can be resistant to low temperatures and can remain stable in a relatively low temperature working environment.

[0080] Furthermore, an insulating reinforced insulating support layer can be added to the surface of the third conductive layer serving as the electromagnetic shielding layer. A polymer layer is then provided on top of the reinforced insulating support layer, which is then patterned and embossed to form a grid-like groove. The grid-like groove is filled with a conductive material to form a fourth conductive layer. The fourth conductive layer can also be connected to an external device to receive current, making it a heating layer. In this way, the entire conductive film product has four conductive layers. Depending on the application scenario, especially in environments that emphasize safety or low-temperature operation, two of the conductive layers can be used for touch display, one conductive layer can be used as an electromagnetic shielding layer, and the other layer can be used as a heating layer. This allows the product to be used in low-temperature environments without affecting touch control. At the same time, electromagnetic shielding is safer, which is not shown in the figure.

[0081] This embodiment also provides a method for preparing the ultra-thin composite transparent conductive film, which includes the following main steps:

[0082] 1. First, apply UV curing glue on the surface of the transparent substrate.

[0083] Before applying UV curing glue on the surface of the transparent substrate, the transparent substrate may be preferably aged. Of course, depending on the material, the transparent substrate may not be aged, but some materials may have upper and lower line size deviations if they are not aged. Among them, the aging method may be to place the transparent substrate under a plasma blower at a temperature of 50 to 150°C for 5 to 60 seconds to remove impurities on the surface of the substrate and stabilize the properties of the substrate; the material of the transparent substrate may be PET, PC, PMMA, etc., and the thickness of the transparent substrate may be 50 to 200 microns. The above-mentioned UV curing glue may also be replaced by a thermosetting coating, but UV glue is preferred.

[0084] 2. Then, pattern imprinting is performed on the UV curing adhesive based on a pattern imprinting technology and cured to form a first UV adhesive layer with grid-shaped grooves of the first conductive layer and lead grooves of the first lead area.

[0085] The patterned embossing method can be: a first UV adhesive layer is applied to a transparent substrate, and a metal stamp with a patterned pattern is brought into contact with the transparent substrate by rolling or flat pressing. Simultaneously or with a delay, UV curing or other means is used to transfer the pattern on the stamp surface to the first UV adhesive layer of the transparent substrate, thereby forming a patterned pattern with mesh lines as grooves. The grooves have a width of 1 to 20 microns and a depth of 4 to 5 microns. The thickness of the first UV adhesive layer is 8 to 12 microns.

[0086] 3. Fill the groove of the first UV adhesive layer with conductive material to form a first conductive layer and a first lead area.

[0087] In this step, the patterned grooves formed by embossing the UV curing adhesive surface can be filled with nanosilver paste using a scraping technique. Due to the self-leveling effect, the nanosilver paste will automatically deposit in the grooves during the scraping process. In order to ensure that the silver paste is evenly distributed in the patterned grooves, multiple scraping operations can be performed to ensure that the silver particles fill the grooves. After scraping, the UV curing adhesive surface needs to be polished to remove excess silver paste. The first lead area is arranged on the periphery of the first conductive layer.

[0088] 4. Apply UV curing adhesive to the surface of the first UV adhesive layer to form a second UV adhesive layer as a reinforced insulating support layer. The second UV adhesive layer can be embossed or applied using a flat, patternless mold or a mirror roller with a high surface finish to ensure the surface flatness of the reinforced insulating support layer. The thickness of the reinforced insulating support layer is preferably 5 to 10 microns. Since the lead area needs to be connected to external devices, the electrical connection area of ​​the first lead area cannot be coated with a UV adhesive layer to prevent subsequent processes from damaging the structure or conductivity of the lead area. Other methods such as selective coating can also be used to provide the second UV adhesive layer.

[0089] 5. Further apply UV curing glue on the second UV glue layer to form a third UV glue layer, perform alignment pattern imprinting on the UV curing glue and cure it to form a third UV glue layer with grid-shaped grooves of the second conductive layer and lead grooves of the second lead area.

[0090] To ensure that the grid-shaped grooves of the second conductive layer do not deviate significantly from the grid-shaped grooves of the first conductive layer, the molds used to stamp the first and third UV adhesive layers are equipped with positioning targets. There can be multiple positioning targets, distributed around the mold and not overlapping with other patterns. When stamping the third UV adhesive layer, the positioning targets on the mold are aligned with the positioning targets stamped on the first UV adhesive layer. The first UV adhesive layer is stamped with a first alignment mark and a groove pattern; the third UV adhesive layer is stamped with a second alignment mark and a groove pattern. The patterns of the first and second alignment marks are either retained or cut out of the transparent conductive film product.

[0091] The second lead area is arranged at the periphery of the second conductive layer, and the electrical connection area of ​​the second lead area cannot overlap with the electrical connection area of ​​the first lead area.

[0092] 6. Fill the groove of the third UV adhesive layer with conductive material to form a second conductive layer and a second lead area.

[0093] The first lead area and the second lead area are connected to the test equipment to test the function and performance of the ultra-thin composite transparent conductive film.

[0094] The above steps are the preparation method of a single ultra-thin composite transparent conductive film.

[0095] Since the steps for producing the ultra-thin composite transparent conductive film are relatively numerous, if a single piece is produced, the efficiency is extremely low. This embodiment improves on the above preparation method and provides a preparation method for mass production of the ultra-thin composite transparent conductive film, including the following main steps:

[0096] 1. First, a first layer of UV curing adhesive is coated on the surface of a roll of aged transparent substrate through a roll-to-roll process. Then, a pattern is embossed on the UV curing adhesive and cured to form a whole roll of film material including multiple first UV adhesive layers connected end to end, that is, a film material forming multiple continuous first UV adhesive layer units. The first UV adhesive layer has a grid-like groove of the first conductive layer, a lead groove of the first lead area, and a groove for the positioning target.

[0097] 2. Use multiple scrapers to fill the grid-shaped grooves of the first conductive layer of the multiple first UV adhesive layers and the lead grooves of the first lead area on the entire roll of film in a roll-to-roll coating manner with conductive material to form multiple first conductive layers and the first lead area.

[0098] The specific roll-to-roll coating method is: the entire roll of film moves under the traction of an automated traction device, the nozzle automatically sprays conductive material, and multiple scrapers are perpendicular to the moving direction, set above the film and in contact with the film. The scrapers remain stationary and the film moves, which will not cause waste of conductive material and save manpower. At the same time, an automatic wiping head can also be set to wipe the excess conductive material on the surface of the first UV adhesive layer.

[0099] 3. Through the roll-to-roll process, a second layer of UV curing adhesive is coated on the surface of the first UV adhesive layer, and a patternless embossing is performed on the second layer of UV curing adhesive and cured, thereby forming a plurality of reinforced insulating support layers, i.e., the second UV adhesive layer, on the surface of the plurality of first UV adhesive layers of the entire roll of film material, wherein the surface of the electrical connection area of ​​the first lead area of ​​the first UV adhesive layer is not coated with the UV adhesive layer.

[0100] 4. After aligning the positioning target on the mold for imprinting the third UV adhesive layer with the positioning target imprinted on the first UV adhesive layer, a third layer of UV curing adhesive is coated on the second UV adhesive layer (reinforced insulating support layer) of the entire roll of film material through a roll-to-roll process, and a graphic imprint is performed on the UV curing adhesive and cured to form a whole roll of film material including multiple third UV adhesive layers connected end to end, wherein the third UV adhesive layer has a grid-like groove of the second conductive layer and a lead groove of the second lead area.

[0101] Due to the alignment process, the grid-shaped groove areas of the multiple second conductive layers of the entire roll of film are respectively arranged directly above the grid-shaped groove areas of the multiple first conductive layers, and the electrical connection areas of all the second lead areas are staggered with the electrical connection areas of the first lead areas.

[0102] 5. Use multiple scrapers to fill the grooves of the multiple third UV adhesive layers of the entire roll of film material in a roll-to-roll coating manner with conductive material to form multiple second conductive layers and second lead areas.

[0103] 6. Slice the entire roll of ultra-thin composite transparent conductive film to obtain a plurality of ultra-thin composite transparent conductive films.

[0104] The above preparation method enables the mass production of ultra-thin composite transparent conductive films with high production efficiency. At the same time, the roll-to-roll coating method of conductive materials can reduce the waste of conductive materials and lower production costs. Taking nano silver paste as an example, a 500 ml bottle of nano silver paste costs tens of thousands of yuan.

[0105] Example 2

[0106] like Figure 4 As shown, this embodiment discloses an ultra-thin composite transparent conductive film, comprising a transparent substrate 1, a first conductive layer 3 disposed on the transparent substrate, and a second conductive layer 6 disposed on the first conductive layer 3, wherein a transparent reinforced insulating support layer 4 is disposed between the first conductive layer 3 and the second conductive layer 6, and the second conductive layer 6 is disposed on the cured reinforced insulating support layer 4;

[0107] Different from the first embodiment, the first conductive layer of the second embodiment is formed by a conductive material filled in grid grooves provided on the transparent substrate 1 .

[0108] It should be noted that, compared with Example 1, the first UV adhesive layer is removed in this Example 2, which is equivalent to a thinner thickness of the ultra-thin composite transparent conductive film. However, the effect of directly embossing the grid grooves on the transparent substrate is not as good as the effect of embossing the grid grooves on the UV light-curing coating, because the UV light-curing coating is still in a liquid state during embossing, and solidifies after embossing, and the groove depth will not rebound.

[0109] This second embodiment further provides a method for preparing the ultra-thin composite transparent conductive film, which includes the following main steps:

[0110] (1) Patterning grid-shaped grooves on a transparent substrate 1;

[0111] (2) filling the grooves embossed in step (1) with a conductive material to form a first conductive layer 3;

[0112] (3) coating a second UV adhesive layer, i.e., a transparent reinforced insulating support layer 4, on the first conductive layer 3 and curing the layer;

[0113] (4) coating a third UV adhesive layer 5 on the transparent reinforced insulating support layer 4, patterning and embossing grid-shaped grooves on the third UV adhesive layer 5 and curing the resultant;

[0114] (5) Fill the grooves embossed in step (4) with conductive material to form a second conductive layer 6.

[0115] In the above step (1), a mold can be used to directly emboss a grid-like groove on a transparent substrate (which can be PET or PMMA) with a groove depth of 4-5 microns. The specific implementation methods and parameters of the remaining steps refer to the preparation method of the first embodiment.

[0116] It should be noted that the dimensional parameters listed in the above embodiments are merely illustrative of the implementation of the present invention. For example, the groove width, as long as the groove width is less than the human eye's maximum resolution, will not affect normal viewing of the display device. The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent structures or equivalent processes derived from the present specification and drawings, or any direct or indirect application in other related technical fields, are also encompassed within the scope of the present invention.

Claims

1. An ultrathin composite transparent conductive film comprising a transparent substrate, characterized in that: One side of the transparent substrate is provided with a first UV adhesive layer, a second UV adhesive layer, and a third UV adhesive layer; The first UV adhesive layer is a first layer of UV curable adhesive coated on the surface of the transparent substrate. The first UV adhesive layer is patterned and embossed and cured to form the grid-shaped grooves of the first conductive layer and the lead grooves of the first lead area. The grid-shaped grooves of the first conductive layer and the lead grooves of the first lead area are filled with a conductive material. The depth of the grid-shaped grooves of the first conductive layer and the lead grooves of the first lead area are less than the thickness of the first UV adhesive layer. A second UV adhesive layer is provided on the surface of the first UV adhesive layer, and the second UV adhesive layer serves as a reinforced insulating support layer; A third UV adhesive layer is provided on the surface of the second UV adhesive layer. The surface of the third UV adhesive layer is patterned and cured to form grid-shaped grooves of the second conductive layer and lead grooves of the second lead area. The grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area are filled with a conductive material. The depth of the grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area is no greater than the thickness of the third UV adhesive layer. The thickness of the second UV adhesive layer is 1 to 10 microns, the friction coefficient of the surface of the second UV adhesive layer is 0.4-1.0, the first UV adhesive layer, the third UV adhesive layer and the second UV adhesive layer use the same UV curing adhesive, and the first UV adhesive layer, the second UV adhesive layer and the third UV adhesive layer are subjected to adhesion enhancement treatment.

2. The ultra-thin composite transparent conductive film according to claim 1, wherein: The first UV adhesive layer is patterned and embossed and cured to form grid-shaped grooves of the first conductive layer, lead grooves of the first lead area, and alignment pattern grooves of the first alignment mark, wherein the grid-shaped grooves of the first conductive layer, the lead grooves of the first lead area, and the alignment pattern grooves of the first alignment mark are all filled with conductive material, and the depth of the grid-shaped grooves of the first conductive layer, the lead grooves of the first lead area, and the alignment pattern grooves of the first alignment mark are all less than the thickness of the first UV adhesive layer; The surface of the third UV adhesive layer is patterned and cured to form grid-like grooves of the second conductive layer, lead grooves of the second lead area, and alignment pattern grooves of the second alignment mark. The grid-like grooves of the second conductive layer, the lead grooves of the second lead area, and the alignment pattern grooves of the second alignment mark are all filled with conductive material. The depth of the grid-like grooves of the second conductive layer, the lead grooves of the second lead area, and the alignment pattern grooves of the second alignment mark is no greater than the thickness of the third UV adhesive layer. The patterns of the first alignment mark and the second alignment mark are either retained or cut out in the transparent conductive film product.

3. The ultra-thin composite transparent conductive film according to claim 1, wherein: The electrical connection area of ​​the first lead area is not coated with the second layer of UV curing glue, and the electrical connection area of ​​the second lead area of ​​the third UV glue layer does not overlap with the electrical connection area of ​​the first lead area of ​​the first UV glue layer.

4. The ultra-thin composite transparent conductive film according to claim 1, wherein: An adhesion-enhancing layer is coated or treated between the transparent substrate and the first UV adhesive layer. An adhesion-promoting coating is coated between the first UV adhesive layer, the second UV adhesive layer and the third UV adhesive layer.

5. The ultra-thin composite transparent conductive film according to claim 1, wherein: The second UV adhesive layer is a composite layer formed by coating UV curing adhesive multiple times on the surface of the first UV adhesive layer, and the surface of the electrical connection area of ​​the first lead area is not covered by the second UV adhesive layer.

6. The ultra-thin composite transparent conductive film according to claim 1, wherein: The grid-shaped grooves of the first conductive layer and the second conductive layer and the lead grooves of the first lead area and the second lead area are filled with nano silver paste or nano copper paste or graphene material or nano silver wire or carbon nano tube material.

7. The ultra-thin composite transparent conductive film according to claim 1, wherein: A protective layer is provided on the upper surface of the third UV adhesive layer, and the protective layer is a polymer layer. The first UV adhesive layer, the second UV adhesive layer, the third UV adhesive layer, the protective layer and the transparent substrate together form a composite transparent conductive film, and the electrical connection area of ​​the second lead area of ​​the third UV adhesive layer does not overlap with the electrical connection area of ​​the first lead area of ​​the first UV adhesive layer.

8. A method for preparing an ultra-thin composite transparent conductive film, characterized in that The steps include: Step 1: A first layer of UV curable adhesive is coated on the surface of the transparent substrate, and a pattern is embossed and cured on the first layer of UV curable adhesive to form a grid-like groove of the first conductive layer, a lead groove of the first lead area, and a pattern groove of the first alignment mark, so that the depth of the grid-like groove and the lead groove is less than the thickness of the first UV adhesive layer; Step 2: Filling the grid-shaped grooves of the first conductive layer, the lead grooves of the first lead area, and the pattern grooves of the first alignment mark with a conductive material to form a first UV adhesive layer; Step 3: Then, a second layer of UV curing adhesive is selectively coated on the surface of the first UV adhesive layer to form a second UV adhesive layer. The electrical connection area of ​​the first lead area is not coated with the second layer of UV curing adhesive. The thickness of the second UV adhesive layer is 1 to 10 microns, and the friction coefficient of the surface of the second UV adhesive layer is 0.4 to 1.

0. Step 4: Coating a third layer of UV curing adhesive on the surface of the second UV adhesive layer, performing patterned alignment embossing and curing on the third layer of UV curing adhesive to form a grid-shaped groove with a second conductive layer, a lead groove of the second lead area, and a patterned groove of the second alignment mark, wherein the depth of the grid-shaped groove of the second conductive layer and the lead groove of the second lead area is no greater than the thickness of the third UV adhesive layer, and the electrical connection area of ​​the second lead area does not overlap with the electrical connection area of ​​the first lead area; Step 5: Fill the grid-shaped grooves of the second conductive layer, the lead grooves of the second lead area, and the graphic grooves of the second alignment mark with conductive material. The first UV adhesive layer, the third UV adhesive layer, and the second UV adhesive layer use the same UV curing adhesive, and perform adhesion enhancement treatment between the first UV adhesive layer, the second UV adhesive layer, and the third UV adhesive layer.

9. An ultrathin composite transparent conductive film structure comprising a transparent substrate, characterized in that: One side of the transparent substrate is provided with a first UV adhesive layer, a second UV adhesive layer, and a third UV adhesive layer; The first UV adhesive layer is a first layer of UV curable adhesive coated on the surface of the transparent substrate. The first layer of UV curable adhesive is patterned and embossed and cured to form grid-like grooves in the first conductive layer. The grid-like grooves in the first conductive layer are filled with a conductive material. The depth of the grid-like grooves is less than the thickness of the first UV adhesive layer. The second UV adhesive layer is a second layer of UV curable adhesive provided on the surface of the first UV adhesive layer, and is cured to form a second UV adhesive layer serving as a reinforced insulating support layer. The thickness of the second UV adhesive layer is 1 to 10 microns, and the friction coefficient of the surface of the second UV adhesive layer is 0.4-1.

0. The third UV adhesive layer is a third layer of UV curing adhesive provided on the surface of the second UV adhesive layer. The third layer of UV curing adhesive is patterned and embossed and cured to form a grid-shaped groove with a second conductive layer. The grid-shaped grooves of the second conductive layer are filled with a conductive material. The depth of the grid-shaped grooves is no greater than the thickness of the third UV adhesive layer. The first UV adhesive layer, the third UV adhesive layer, and the second UV adhesive layer use the same UV curing adhesive, and adhesion-enhancing treatment is performed between the first UV adhesive layer, the second UV adhesive layer, and the third UV adhesive layer.

10. A touch display panel, comprising a display device, characterized in that: It also includes the ultra-thin composite transparent conductive film according to any one of claims 1 to 7.

11. A large-scale all-in-one touchscreen device, comprising a display device, a CPU processor, and a power supply, characterized in that: The display device includes a touch panel, and the touch panel further includes the ultra-thin composite transparent conductive film according to any one of claims 1 to 7.

12. A composite transparent conductive film comprising a transparent substrate, characterized in that: Patterning is performed on one side of the transparent substrate to form grid-shaped grooves of the first conductive layer and lead grooves of the first lead area, wherein the grid-shaped grooves of the first conductive layer and the lead grooves of the first lead area are filled with a conductive material; A second UV adhesive layer is provided on one side of the transparent substrate forming the first conductive layer, the second UV adhesive layer serving as a reinforced insulating support layer, the electrical connection area of ​​the first lead area is not coated with the second UV adhesive layer, the thickness of the second UV adhesive layer is 1 to 10 microns, and the friction coefficient of the surface of the second UV adhesive layer is 0.4-1.0; A third UV adhesive layer is provided on the surface of the second UV adhesive layer. The surface of the third UV adhesive layer is patterned and cured to form grid-shaped grooves of the second conductive layer and lead grooves of the second lead area. The grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area are filled with a conductive material. The depths of the grid-shaped grooves of the second conductive layer and the lead grooves of the second lead area are not greater than the thickness of the third UV adhesive layer. The electrical connection area of ​​the second lead area does not overlap with the electrical connection area of ​​the first lead area. The first UV adhesive layer, the third UV adhesive layer, and the second UV adhesive layer use the same UV curing adhesive. The first UV adhesive layer, the second UV adhesive layer, and the third UV adhesive layer are subjected to an adhesion-enhancing treatment.

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