Flexible conductive film for integrated black touch control and preparation method and application of flexible conductive film

Abstract

The invention relates to the technical field of touch display, and particularly discloses an integrated black touch flexible conductive film and a preparation method and application thereof.The flexible conductive film comprises a base material layer, and the base material layer is sequentially provided with an organic coating layer, an inorganic toning layer and a conductive layer from bottom to top; wherein the organic coating layer is prepared by taking an organic polymer as a main body and adding inorganic nanoparticles and siloxane; the inorganic toning layer is formed by overlapping at least one low-refractive-index layer and at least one high-refractive-index layer. Through matching of refractive indexes of the organic coating layer, the insulating inorganic substance layer and the conductive layer, after the flexible touch sensor is manufactured, the flexible touch sensor is matched with an LCD screen and a cover plate to have an excellent integrated black effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of touch display, and in particular relates to an integrated black touch flexible conductive film and a preparation method and application thereof. Background Art

[0002] Currently, all display products with black borders are pursuing the aesthetic effect of "black screen". Figure 1 As shown. Usually, the test of integrated black is to test the chromaticity values ​​(L, a*, b* values) of the BM area and the visual area (VA), and calculate the △E value through the formula.

[0003] ; The industry believes that when △E≤2, the integrated black effect is achieved.

[0004] The chromaticity values ​​of existing LCD screens on the market are basically L values ​​25~30, a* values ​​-1.5~0.7, and b* values ​​-1.7~1.3, while the chromaticity values ​​of black ink are basically L values ​​25~29, a* values ​​-1~0.5, and b* values ​​-1~0.5. Therefore, for conventional screens without external sensors, it is easy to achieve one-piece black by adjusting the chromaticity value of the ink. However, for touch screens with external sensors, especially touch sensors with flexible film substrates, since the substrate itself has a certain chromaticity value, and also has different chromaticity values ​​after being plated with a conductive layer, after the sensor is made through processes such as etching, the overall chromaticity value of the sensor changes too much, and it is impossible to meet the one-piece black by adjusting the ink chromaticity. At the same time, due to the color difference between the etched area and the unetched area (conductive area) of the sensor, the one-piece black cannot take into account all areas at the same time. As follows Figure 2 As shown in the figure, the large area is the ITO area, and the area in the middle of the line is the etching area. In order to ensure a good integrated black effect, the chromaticity of the conductive area and the etching area must be close, and the chromaticity value of the sensor as a whole after being bonded to the LCD screen must be close to the current mainstream black ink. Summary of the invention

[0005] The present invention provides a flexible conductive film for integrated black touch control, and a preparation method and application thereof, which controls the L, a*, and b* of the entire material from the film-sensor raw material end, so that the overall chromaticity value of the sensor is close to the chromaticity of the screen itself, so that after the external sensor is attached to the screen, the overall color is still close to the single screen color, and only a single fine-tuning of the ink chromaticity is required to achieve the integrated black effect.

[0006] The technical solution of the present invention is to provide an integrated black touch flexible conductive film, characterized in that it includes a substrate layer, on which an organic coating layer, an inorganic coloring layer and a conductive layer are arranged in sequence from bottom to top; wherein the organic coating layer is mainly composed of an organic polymer, to which inorganic nanoparticles and siloxane are added; and the inorganic coloring layer includes at least one layer of low refractive index and at least one layer of high refractive index layer stacked together.

[0007] Optionally, the substrate is PET, PMMA, TAC, PP, PE, PI or COP.

[0008] Optionally, the organic coating layer satisfies at least one of the following conditions: The organic polymer is polyacrylate, polyurethane or epoxy resin; The inorganic nanoparticles are zirconium oxide, titanium oxide and / or aluminum oxide; The siloxane is polysiloxane or modified siloxane, and the modified siloxane is specifically modified with a methyl group, a hydroxyl group or a carboxyl group.

[0009] Optionally, in the organic coating layer, the added amount of inorganic nanoparticles is 3% to 15% of the total material mass.

[0010] Optionally, in the organic coating layer, the added amount of siloxane is 1% to 10% of the total material mass.

[0011] Optionally, the low refractive index material is one or more of silicon oxide and magnesium fluoride, and the high refractive index material is one or more of zirconium oxide, titanium oxide, aluminum oxide, silicon nitride, and hafnium oxide. The thickness of each refractive index layer is adjusted according to the material type and the target chromaticity, the thickness of a single inorganic layer is 5 to 130 nm, and the number of coating layers is preferably an even number of 2, 4, 6, or the like.

[0012] Optionally, the thickness of a single layer of material in the inorganic color-tuning layer is 5-130 nm.

[0013] Optionally, the conductive layer is made of ITO, ATO or AZO. The target square resistance of the conductive film is determined.

[0014] The present invention also relates to a method for preparing the integrated black touch flexible conductive film, comprising the following steps: An organic polymer, inorganic nanoparticles and siloxane are mixed to form a coating liquid, which is coated on the surface of the substrate layer and cured to form an organic coating layer. A low refractive index layer and a high refractive index layer are then sputtered on the organic coating layer by a magnetron sputtering method to form an inorganic coloring layer. Finally, an ITO layer is sputtered on the inorganic coloring layer by magnetron sputtering to obtain a flexible conductive film.

[0015] The present invention also relates to the application of the integrated black touch flexible conductive film in the preparation of an integrated black film-sensor.

[0016] The present invention has the following beneficial effects: The flexible conductive film provided by the present invention uses a flexible transparent film as a substrate, and an organic coating layer, an inorganic coloring layer and a conductive layer are sequentially arranged thereon, wherein the organic coating layer is mainly composed of an organic polymer, and inorganic nanoparticles are added to adjust the refractive index of the coating, and siloxane is added to effectively increase the bonding force between the organic coating layer and the inorganic coloring layer; the inorganic coloring layer is alternately stacked with a low refractive index layer and a high refractive index layer, and the chromaticity value of the entire material is adjusted by different refractive indices to achieve a chromaticity close to that of the etching area and the conductive area, and the chromaticity value is close to that of the black ink after the entire LCD screen is attached, which is convenient for debugging the integrated black effect. Finally, a conductive layer is sputtered on the inorganic coloring layer to achieve the conductive function of the touch function.

[0017] The present invention coats a coating with an inorganic compound adhesion-increasing coating on the surface of a flexible film substrate, and then magnetron sputters inorganic compounds with different refractive indices on the coating surface. By matching multiple layers of compounds with different refractive indices, the color difference between the conductive area and the etching area of ​​the conductive film can be adjusted, and the overall color of the conductive film can be adjusted to ensure that the chromaticity value of the film after being made into a touch sensor is close to the chromaticity value of the LCD screen, so that the integrated black effect of the external flexible sensor touch display screen can be effectively achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of a common external touch sensor display mentioned in the background technology.

[0019] Figure 2 This is a schematic diagram of the structure of the flm sensor etching circuit.

[0020] Figure 3 A structural schematic diagram of a flexible conductive film is provided for the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0022] The present invention can match the overall chromaticity of the sensor+LCD screen with the black ink by adjusting the material, number of layers and single layer thickness of the inorganic color adjustment layer for conductive films with different square resistance requirements and LCD screens with different chromaticities, thereby easily achieving an integrated black effect.

[0023] Comparative Example 1 A polyacrylate coating liquid containing 5% zirconium oxide was coated on a 125 μm thick PET surface and cured. A transparent conductive film was prepared by first sputtering 20 nm silicon oxide and then sputtering 18 nm ITO on the coating surface by magnetron sputtering.

[0024] Example 1 A polyacrylate coating liquid containing 5% zirconium oxide and 3% polysiloxane was coated on a 125um thick PET surface and cured. A transparent conductive film was prepared by sputtering 20nm silicon oxide and then 18nm ITO on the coating surface using a magnetron sputtering method.

[0025] The boiling adhesion of the transparent conductive films obtained in Comparative Example 1 and Example 1 was tested by boiling in pure water for 2 hours and then performing a 100-grid test. The 100-grid test standard refers to JIS K-5600 standard.

[0026] Table 1

[0027] It can be seen from Table 1 that in Example 1 of the present invention, the adhesion of the magnetron sputtering inorganic compound to the organic coating can be effectively improved by adding polysiloxane to the coating solution.

[0028] Comparative Example 2 A polyacrylate coating containing 5% zirconium oxide and 3% polysiloxane was coated on the surface of 125um PET and cured. A 20nm silicon oxide was first sputtered on the surface of the coating by magnetron sputtering, and then an 18nm ITO was sputtered to make a transparent conductive film. The chromaticity value of the ITO area was tested, and then the ITO was etched with hydrochloric acid and the chromaticity value of the etched area was tested to calculate the color difference value. The sensor was made of this conductive film and then bonded to the Tianma LCD screen. The black ink was adjusted according to the overall chromaticity value after bonding, and the integrated black effect was tested after the cover was screen printed.

[0029] Example 2 A polyacrylate coating containing 5% zirconium oxide and 3% polysiloxane was coated on the surface of 125um PET and cured. 13nm silicon nitride, 45nm silicon oxide, and 18nm ITO were plated on the surface of the coating by magnetron sputtering to make a transparent conductive film. The chromaticity value of the ITO area was tested, and then the chromaticity value of the etched area was tested after the ITO was etched with hydrochloric acid, and the color difference value was calculated. The sensor was made of this conductive film and then bonded to the Tianma LCD screen. The black ink was adjusted according to the overall chromaticity value after bonding, and the integrated black effect was tested after the cover was screen printed.

[0030] Example 3 A polyacrylate coating containing 5% zirconium oxide and 3% polysiloxane was coated on the surface of 125um PET and cured. 5.5nm niobium oxide, 55nm silicon oxide, and 18nm ITO were plated on the surface of the coating by magnetron sputtering to make a transparent conductive film. The chromaticity value of the ITO area was tested, and then the ITO was etched with hydrochloric acid and the chromaticity value of the etched area was tested to calculate the color difference value. The sensor was made of this conductive film and then bonded to the Tianma LCD screen. The black ink was adjusted according to the overall chromaticity value after bonding, and the integrated black effect was tested after screen printing the cover.

[0031] Example 4 A polyacrylate coating containing 5% zirconium oxide and 3% polysiloxane was coated on the surface of 125um PET and cured. 12nm silicon nitride, 51nm silicon oxide, 28nm silicon nitride, 52nm silicon oxide, and 27nm ITO were plated on the surface of the coating by magnetron sputtering to make a transparent conductive film. The chromaticity value of the ITO area was tested, and then the chromaticity value of the etched area was tested after the ITO was etched with hydrochloric acid, and the color difference value was calculated. The sensor was made of the conductive film and then bonded to the Tianma LCD screen. The black ink was adjusted according to the overall chromaticity value after bonding, and the integrated black effect was tested after the cover was screen printed.

[0032] Example 5 A polyacrylate coating containing 5% zirconium oxide and 3% polysiloxane was coated on the surface of 125um PET and cured. 6nm niobium oxide, 50nm silicon oxide, 15nm niobium oxide, 51nm silicon oxide, and 27nm ITO were plated on the surface of the coating by magnetron sputtering to make a transparent conductive film. The chromaticity value of the ITO area was tested, and then the chromaticity value of the etched area was tested after the ITO was etched with hydrochloric acid, and the color difference value was calculated. The sensor was made of the conductive film and then bonded to the Tianma LCD screen. The black ink was adjusted according to the overall chromaticity value after bonding, and the integrated black effect was tested after the cover was screen printed.

[0033] The test results of Control Example 2 and Examples 2 to 5 are shown in Table 2 below (specifically, the test was performed using a Konica Minolta CM700D spectrum tester).

[0034] Table 2

[0035] As can be seen from Table 2, before the conductive layer is plated on the flexible material, by adding an inorganic layer composed of alternately plated high refractive index and low refractive index materials, the color difference between the conductive area and the etched area after the conductive film material is made into a sensor can be effectively reduced, making the sensor look more integrated. At the same time, through the color adjustment effect of the inorganic color adjustment layer, the chromaticity value of the conductive film material can be adjusted to be close to that of the screen, so that the conductive film material will not significantly change the overall chromaticity after being made into a sensor and bonded to the screen, so that the chromaticity value of the sensor matching screen can match the black ink currently on the market, perfectly achieving an integrated black effect.

[0036] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A flexible conductive film for integrated black touch control, characterized in that: It includes a substrate layer, on which an organic coating layer, an inorganic coloring layer and a conductive layer are arranged in order from bottom to top; the organic coating layer is mainly made of organic polymer, with inorganic nanoparticles and siloxane added; the inorganic coloring layer is composed of at least one layer of low refractive index and at least one layer of high refractive index stacked together.

2. The integrated black touch-sensitive flexible conductive film according to claim 1, characterized in that: The substrate is PET, PMMA, TAC, PP, PE, PI or COP.

3. The integrated black touch-sensitive flexible conductive film according to claim 1, characterized in that: The organic coating layer satisfies at least one of the following conditions: The organic polymer is polyacrylate, polyurethane or epoxy resin; The inorganic nanoparticles are zirconium oxide, titanium oxide and / or aluminum oxide; The siloxane is polysiloxane or modified siloxane, and the modified siloxane is specifically modified with a methyl group, a hydroxyl group or a carboxyl group.

4. The integrated black touch-sensitive flexible conductive film according to claim 1, characterized in that: In the organic coating layer, the added amount of inorganic nanoparticles is 3% to 15% of the total material mass.

5. The integrated black touch-sensitive flexible conductive film according to claim 1, characterized in that: In the organic coating layer, the added amount of siloxane is 1-10% of the total material mass.

6. The integrated black touch-sensitive flexible conductive film according to any one of claims 1 to 5, characterized in that: The low refractive index material is one or more of silicon oxide and magnesium fluoride, and the high refractive index material is one or more of zirconium oxide, titanium oxide, aluminum oxide, silicon nitride and hafnium oxide.

7. The integrated black touch-sensitive flexible conductive film according to claim 6, characterized in that: The thickness of a single layer of material in the inorganic coloring layer is 5 to 130 nm.

8. The integrated black touch-sensitive flexible conductive film according to claim 1, characterized in that: The conductive layer is made of ITO, ATO or AZO.

9. The method for preparing the integrated black touch flexible conductive film according to any one of claims 1 to 8, characterized in that: The following steps are involved: An organic polymer, inorganic nanoparticles and siloxane are mixed to form a coating liquid, which is coated on the surface of the substrate layer and cured to form an organic coating layer. A low refractive index layer and a high refractive index layer are then sputtered on the organic coating layer by a magnetron sputtering method to form an inorganic coloring layer. Finally, an ITO layer is sputtered on the inorganic coloring layer by magnetron sputtering to obtain a flexible conductive film.

10. Use of the integrated black touch flexible conductive film according to any one of claims 1 to 8 in preparing an integrated black film-sensor.

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