Anti-glare electromagnetic shielding film with high transmittance and preparation method thereof

Abstract

The present invention discloses a high-transmittance anti-glare electromagnetic shielding film and a preparation method thereof. The electromagnetic shielding film includes a transparent thin film substrate, an anti-glare anti-reflection and anti-reflection enhancement layer, and two metal mesh electromagnetic shielding layers, and the two metal mesh electromagnetic shielding layers are respectively arranged on the upper and lower surfaces of the anti-glare anti-reflection and anti-reflection enhancement layer. The preparation method includes the following steps: sputtering a first metal mesh electromagnetic shielding layer on the upper surface of the transparent thin film substrate; sequentially sputtering a first low refractive index thin film layer, a first high refractive index thin film layer, a second low refractive index thin film layer, a second high refractive index thin film layer, a third low refractive index thin film layer, a third high refractive index thin film layer, and a fourth low refractive index thin film layer on the upper surface of the first metal mesh electromagnetic shielding layer to form an anti-glare anti-reflection and anti-reflection enhancement layer; sputtering a second metal mesh electromagnetic shielding layer on the upper surface of the anti-glare anti-reflection and anti-reflection enhancement layer. The electromagnetic shielding film prepared by the technical solution of the present invention has the advantages of high shielding efficiency, high transmittance, good wave absorption performance, good weather resistance, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical thin films, and particularly relates to an anti-glare electromagnetic shielding film with high transmittance and a preparation method thereof. Background Art

[0002] With the development of society and the improvement of living quality, people have put forward higher requirements for environmental quality and the shielding efficiency of electromagnetic radiation. For example, with the popularization of wireless charging and the development of 5G or even 6G technology, the shielding efficiency of shielding materials needs to be greater than 50 dB and have high transmittance.

[0003] Generally, people prepare electromagnetic shielding glass by directly sputtering or coating a conductive film on glass. However, for the electromagnetic shielding film prepared by this method, its electromagnetic shielding efficiency and optical transmittance do not meet the actual requirements. Therefore, there is an urgent need to develop a new type of electromagnetic shielding film and its preparation method to solve the problems such as low shielding efficiency and low transmittance of the electromagnetic shielding film prepared by the existing technology.

[0004] The invention patent with the application publication number CN105845203A discloses a flexible copper mesh grid-based transparent conductive film, which includes a flexible transparent substrate, an anti-reflection and anti-reflection enhancement layer, and a copper mesh grid conductive layer. The anti-reflection and anti-reflection enhancement layer is arranged between the flexible transparent substrate and the copper mesh grid conductive layer; the anti-reflection and anti-reflection enhancement layer includes a low refractive index thin film layer and a high refractive index thin film layer, and the low refractive index thin film layer and the high refractive index thin film layer are alternately stacked, and the number of low refractive index thin film layers is more than or equal to the number of high refractive index thin film layers; the copper mesh grid conductive layer includes a copper mesh grid layer and a copper oxide layer, and the copper oxide layer is arranged on the upper surface of the copper mesh grid layer or on the upper and lower surfaces of the copper mesh grid layer. This technical solution directly sputters the anti-reflection and anti-reflection enhancement layer on the flexible transparent substrate. Although it can improve the transmittance of the substrate, the situation where the anti-reflection and anti-reflection enhancement layer is in direct contact with the flexible transparent substrate still cannot meet the environmental weather resistance of the thin film material; sputtering copper oxide on the surface of the copper metal film can prevent the copper metal from being oxidized, but it increases the structural complexity and manufacturing process of the thin film material, and still cannot achieve the effect of completely preventing the copper metal from being oxidized only by sputtering copper oxide; in addition, this technical solution cannot improve the shielding efficiency and wave absorption ability of the thin film material.

[0005] The invention patent with the publication number of CN111477382A discloses a porous metal composite transparent conductive film and a preparation method thereof. The conductive film includes a transparent substrate, and a protective antireflective metal oxide layer, a porous metal conductive layer, and another protective antireflective metal oxide layer are sequentially prepared on one or both surfaces of the transparent substrate. The porous metal conductive layer is arranged between the two protective antireflective metal oxide layers. The porous metal conductive layer is prepared by a mask method, and the mask material is polyimide spheres. This technical solution prevents the metal film from being oxidized by the protective antireflective metal oxide layer and the method of preparing the porous metal by the mask method. Although it can improve the oxidation resistance of the metal film, it increases the structural complexity and manufacturing process of the film, and still cannot achieve the effect that the metal film is completely not oxidized only by this way. In addition, this technical solution cannot improve the shielding efficiency and wave absorption ability of the film. Summary of the Invention

[0006] To solve the problems existing in the prior art, the present invention provides an antiglare electromagnetic shielding film with high transmittance, which includes a transparent thin film substrate, an antiglare antireflection and antireflection enhancement layer, and a metal mesh grid electromagnetic shielding layer. The metal mesh grid electromagnetic shielding layer includes a first metal mesh grid electromagnetic shielding layer and a second metal mesh grid electromagnetic shielding layer. The arrangement order of the transparent thin film substrate, the antiglare antireflection and antireflection enhancement layer, and the metal mesh grid electromagnetic shielding layer from bottom to top is the transparent thin film substrate, the first metal mesh grid electromagnetic shielding layer, the antiglare antireflection and antireflection enhancement layer, and the second metal mesh grid electromagnetic shielding layer.

[0007] Preferably, the material of the transparent thin film substrate is any one of polyethylene terephthalate (PET), inorganic glass, and organic glass.

[0008] In any of the above solutions, preferably, the antiglare antireflection and antireflection enhancement layer sequentially includes a first low refractive index thin film layer, a first high refractive index thin film layer, a second low refractive index thin film layer, a second high refractive index thin film layer, a third low refractive index thin film layer, a third high refractive index thin film layer, and a fourth low refractive index thin film layer from bottom to top.

[0009] In any of the above solutions, preferably, the materials of the first low refractive index thin film layer, the second low refractive index thin film layer, the third low refractive index thin film layer, and the fourth low refractive index thin film layer are silicon dioxide (SiO2), magnesium fluoride (MgF2), silicon dioxide (SiO2), and magnesium fluoride (MgF2), respectively.

[0010] In any of the above solutions, preferably, the materials of the first high refractive index thin film layer, the second high refractive index thin film layer, and the third high refractive index thin film layer are tantalum pentoxide (Ta2O5), indium tin oxide (In2O3 - SnO2), and hafnium dioxide (HfO2), respectively.

[0011] The second high refractive index thin film layer, i.e., the indium tin oxide thin film layer, is a transparent conductive film, which has the functions of anti-reflection and anti-glare, electromagnetic shielding, and conductivity.

[0012] In any of the above solutions, preferably, the material of the first metal mesh grid electromagnetic shielding layer is copper alloy Cu 85 Ni8Ti5Cr2, and the material of the second metal mesh grid electromagnetic shielding layer is copper alloy Cu 83 Ni8Ti5Cr2V2.

[0013] Since the oxidation resistance of copper metal is very weak, during use, if copper metal comes into contact with air or organic substances, the copper metal is extremely easy to be oxidized into copper oxide, and copper oxide no longer has good electromagnetic wave reflection performance, thus affecting the shielding efficiency of the core functional layer of the electromagnetic shielding film. In order to fundamentally solve the problem of copper metal oxidation, the present invention alloyizes copper metal and uses different copper alloy components on the contact surface with air on the surface and the contact surface with the organic substrate at the bottom layer, so as to completely prevent the copper metal layer from being oxidized, thus meeting the environmental weather resistance of the electromagnetic shielding film. At the same time, due to the presence of the anti-glare and anti-reflection layer, the thin film can have good anti-reflection and anti-glare functions and scratch resistance.

[0014] The copper alloy Cu 85 The preparation method of Ni8Ti5Cr2 includes the following steps:

[0015] Step 1: Weigh pure metal particles by mass percentage, Cu is 85%, Ni is 8%, Ti is 5%, Cr is 2%, and the purity is not less than 99.99%. Mix the four kinds of pure metal particles evenly;

[0016] Step 2: Put the evenly mixed pure metal particles into a vacuum melting furnace for melting. The melting temperature is 1450 - 1500 °C, and the melting time is 2 - 3 h to form copper alloy Cu 85 Ni8Ti5Cr2.

[0017] The copper alloy Cu 83 The preparation method of Ni8Ti5Cr2V2 includes the following steps:

[0018] Step A: Weigh pure metal particles by mass percentage, Cu is 83%, Ni is 8%, Ti is 5%, Cr is 2%, V is 2%, and the purity is not less than 99.99%. Mix the five kinds of pure metal particles evenly;

[0019] Step B: Put the evenly mixed pure metal particles into a vacuum melting furnace for melting. The melting temperature is 1450 - 1500 °C, and the melting time is 2 - 3 h to form copper alloy Cu 83 Ni8Ti5Cr2V2.

[0020] Preferably, in any of the above solutions, the thickness of the transparent thin film substrate is 50 - 125 μm.

[0021] Preferably, in any of the above solutions, the thicknesses of the first low refractive index thin film layer, the first high refractive index thin film layer, the second low refractive index thin film layer, the second high refractive index thin film layer, the third low refractive index thin film layer, the third high refractive index thin film layer, and the fourth low refractive index thin film layer are 195 - 200 nm, 18 - 20 nm, 35 - 40 nm, 120 - 125 nm, 25 - 30 nm, 15 - 20 nm, and 60 - 65 nm respectively.

[0022] Preferably, in any of the above solutions, the thickness of the first metal mesh electromagnetic shielding layer is 400 - 500 nm, and the thickness of the second metal mesh electromagnetic shielding layer is 500 - 600 nm. More preferably, based on the thickness of the first metal mesh electromagnetic shielding layer being 400 - 500 nm and the thickness of the second metal mesh electromagnetic shielding layer being 500 - 600 nm, the thickness of the first metal mesh electromagnetic shielding layer is 0.75 - 0.85 times the thickness of the second metal mesh electromagnetic shielding layer.

[0023] Both of the two metal mesh electromagnetic shielding layers are hollow mesh structures composed of periodic hexagons.

[0024] In the first metal mesh electromagnetic shielding layer: the side lengths of the hexagons are all 300 - 400 μm, and the line widths of the side lengths are all 10 - 15 μm. More preferably, based on the side length of the hexagon being 300 - 400 μm and the line width of the side length being 10 - 15 μm, the side length is 28 - 34 times the line width.

[0025] In the second metal mesh electromagnetic shielding layer: the side lengths of the hexagons are all 240 - 340 μm, and the line widths of the side lengths are all 8 - 12 μm. More preferably, based on the side length of the hexagon being 240 - 340 μm and the line width of the side length being 8 - 12 μm, the side length is 25 - 36 times the line width.

[0026] While ensuring high transmittance and low reflectivity, the core functional layer of the electromagnetic shielding film can absorb electromagnetic waves and reflect a small amount. The metal mesh electromagnetic shielding layer mainly relies on the metal mesh to play a good role in electromagnetic shielding by reflection. By adopting a double - layer metal mesh and optimizing the spacing between the double - layer metal meshes in the present invention, strong resonance interference can be formed between the double - layer metal meshes for electromagnetic waves. At the same time, a conductive layer is introduced into the anti - glare, anti - reflection, and anti - transmission - increasing layer to further improve the resonance interference efficiency, thereby improving the electromagnetic wave absorption performance of the overall electromagnetic shielding film and showing more excellent electromagnetic shielding efficiency.

[0027] The present invention also provides a method for preparing an anti-glare electromagnetic shielding film with high transmittance, which is applied to the anti-glare electromagnetic shielding film with high transmittance described in any one of the above, and includes the following steps in sequence:

[0028] Step 1: Sputter copper alloy Cu 85 Ni8Ti5Cr2 on the upper surface of a transparent film substrate by using vacuum sputtering coating technology;

[0029] Step 2: Spin-coat a photoresist on the upper surface of the copper alloy Cu 85 Ni8Ti5Cr2, and place it in an oven for baking; after baking is completed, use laser direct writing technology to expose a preset grid pattern, then place it in the oven again for baking to cure the photoresist. After curing is completed, place it in a sodium hydroxide solution for development; put the copper alloy film with the grid pattern into a copper chloride solution for etching. After etching is completed, put it into acetone to remove the photoresist on the surface of the copper alloy Cu 85 Ni8Ti5Cr2 to form a first metal grid electromagnetic shielding layer;

[0030] Step 3: Use vacuum sputtering coating technology to sequentially sputter a first low refractive index film layer, a first high refractive index film layer, a second low refractive index film layer, a second high refractive index film layer, a third low refractive index film layer, a third high refractive index film layer, and a fourth low refractive index film layer on the upper surface of the first metal grid electromagnetic shielding layer to form an anti-glare, anti-reflection, and anti-reflection layer;

[0031] Step 4: Use vacuum sputtering coating technology to sputter copper alloy Cu 83 Ni8Ti5Cr2V2 on the upper surface of the anti-glare, anti-reflection, and anti-reflection layer;

[0032] Step 5: Spin-coat a photoresist on the upper surface of the copper alloy Cu 83 Ni8Ti5Cr2V2, and place it in an oven for baking; after baking is completed, use laser direct writing technology to expose a preset grid pattern, then place it in the oven again for baking to cure the photoresist. After curing is completed, place it in a sodium hydroxide solution for development; put the entire copper alloy film with the grid pattern into a copper chloride solution for etching. After etching is completed, put it into acetone to remove the photoresist on the surface of the copper alloy Cu 83 Ni8Ti5Cr2V2 to form a second metal grid electromagnetic shielding layer. At this time, the anti-glare electromagnetic shielding film with high transmittance can be obtained.

[0033] In Step 1, when sputtering the copper alloy Cu 85 Ni8Ti5Cr2, the sputtering pressure is 0.2 - 0.4 Pa, the sputtering power is 100 - 120 W, and the sputtering gas is pure argon.

[0034] In Step 2, the photoresist used is AZ5214, and the spin coating rate is 3000 - 3500 r / min; baking is performed before and after exposing the grating pattern, with the baking temperature being 110 - 125 °C and the baking time being 30 - 40 min for both; the concentration of sodium hydroxide (NaOH) solution is 0.1 - 0.3 mol / L; the concentration of copper chloride (CuCl2) solution is 0.5 - 0.6 mol / L, the etching temperature is room temperature, and the etching time is 3 - 4 min.

[0035] In Step 3, the sputtering pressures of the first, second, third, and fourth low refractive index thin film layers are all 0.3 - 0.4 Pa, the sputtering powers are all 150 - 200 W, and the sputtering gases are all pure argon. The sputtering pressures of the first and third high refractive index thin film layers are all 0.3 - 0.4 Pa, the sputtering powers are all 200 - 230 W, and the sputtering gases are all pure argon; for the second high refractive index thin film layer, i.e., the indium tin oxide thin film layer, the sputtering pressure is 0.3 - 0.4 Pa, the sputtering power is 100 - 120 W, and the sputtering gas is a mixture of argon and oxygen, where the mass percentage of argon in the mixture is 97.5% and the mass percentage of oxygen in the mixture is 2.5%.

[0036] In Step 4, when sputtering the copper alloy Cu 83 Ni8Ti5Cr2V2, the sputtering pressure is 0.2 - 0.4 Pa, the sputtering power is 120 - 150 W, and the sputtering gas is pure argon.

[0037] In Step 5, the photoresist used is AZ5214, and the spin coating rate is 3000 - 3500 r / min; baking is performed before and after exposing the grating pattern, with the baking temperature being 110 - 125 °C and the baking time being 30 - 40 min for both; the concentration of sodium hydroxide (NaOH) solution is 0.1 - 0.3 mol / L; the concentration of copper chloride (CuCl2) solution is 0.5 - 0.6 mol / L, the etching temperature is room temperature, and the etching time is 3 - 4 min.

[0038] The present invention adopts a double-layer metal mesh grid structure, which can improve the electromagnetic shielding effectiveness of the electromagnetic shielding film; on the basis of maintaining the high electromagnetic shielding effectiveness of the electromagnetic shielding film, in order to improve the transmittance of the electromagnetic shielding film, an anti-glare dielectric structure with anti-reflection and anti-reflection enhancement functions is designed between the double-layer metal mesh grids. In addition to serving as the dielectric of the double-layer metal mesh grid, by introducing a transparent conductive film as a high refractive index material into the anti-glare dielectric structure, it can also serve as a resonance interference layer to further improve the electromagnetic shielding effectiveness of the double-layer metal mesh grid and simultaneously have more excellent wave absorption performance; in order to improve the environmental weather resistance of the electromagnetic shielding film, a new type of copper alloy is designed, and the copper alloy components of the two-layer metal mesh grid are different to meet the weather resistance under the conditions of the surface layer contacting air and the bottom layer contacting organic matter.

[0039] The high-transmittance anti-glare electromagnetic shielding film and its preparation method of the present invention have a simple structure and convenient operation. The prepared electromagnetic shielding film has high electromagnetic shielding effectiveness, low visible light reflectivity, and the electromagnetic shielding performance is mainly absorption-based, with excellent stealth performance. The electromagnetic shielding effectiveness of the electromagnetic shielding film is greater than 50 dB in the range of 2-18 GHz, the electromagnetic wave absorption effectiveness is greater than 40 dB, the visible light transmittance (380-780 nm) reaches more than 90%, and the visible light reflectivity is less than 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 FIG. is a schematic structural diagram of a preferred embodiment of the high-transmittance anti-glare electromagnetic shielding film according to the present invention.

[0041] Description of the reference numerals in the figure: 1 - transparent thin film substrate, 2 - anti-glare anti-reflection and anti-reflection enhancement layer, 21 - first low refractive index thin film layer, 22 - first high refractive index thin film layer, 23 - second low refractive index thin film layer, 24 - second high refractive index thin film layer, 25 - third low refractive index thin film layer, 26 - third high refractive index thin film layer, 27 - fourth low refractive index thin film layer, 3 - first metal mesh grid electromagnetic shielding layer, 4 - second metal mesh grid electromagnetic shielding layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] In order to further understand the content of the present invention, the present invention will be described in detail below in conjunction with specific embodiments.

[0043] Example 1:

[0044] As Figure 1As shown, according to a preferred embodiment of the anti-glare electromagnetic shielding film with high transmittance of the present invention, it includes a transparent thin film substrate 1, an anti-glare anti-reflection and anti-reflection enhancement layer 2, and a metal mesh electromagnetic shielding layer; the metal mesh electromagnetic shielding layer includes a first metal mesh electromagnetic shielding layer 3 and a second metal mesh electromagnetic shielding layer 4; the arrangement order of the transparent thin film substrate 1, the anti-glare anti-reflection and anti-reflection enhancement layer 2, and the metal mesh electromagnetic shielding layer is, from bottom to top in sequence, the transparent thin film substrate 1, the first metal mesh electromagnetic shielding layer 3, the anti-glare anti-reflection and anti-reflection enhancement layer 2, and the second metal mesh electromagnetic shielding layer 4.

[0045] The anti-glare anti-reflection and anti-reflection enhancement layer 2 includes, from bottom to top in sequence, a first low refractive index thin film layer 21, a first high refractive index thin film layer 22, a second low refractive index thin film layer 23, a second high refractive index thin film layer 24, a third low refractive index thin film layer 25, a third high refractive index thin film layer 26, and a fourth low refractive index thin film layer 27.

[0046] The material of the transparent thin film substrate is polyethylene terephthalate (PET).

[0047] The materials of the first low refractive index thin film layer, the second low refractive index thin film layer, the third low refractive index thin film layer, and the fourth low refractive index thin film layer are silicon dioxide (SiO2), magnesium fluoride (MgF2), silicon dioxide (SiO2), and magnesium fluoride (MgF2) respectively.

[0048] The materials of the first high refractive index thin film layer, the second high refractive index thin film layer, and the third high refractive index thin film layer are tantalum pentoxide (Ta2O5), indium tin oxide (In2O3 - SnO2), and hafnium dioxide (HfO2) respectively.

[0049] The material of the first metal mesh electromagnetic shielding layer is copper alloy Cu 85 Ni8Ti5Cr2, and the material of the second metal mesh electromagnetic shielding layer is copper alloy Cu 83 Ni8Ti5Cr2V2. In order to fundamentally solve the problem of copper metal oxidation, in this embodiment, the copper metal is alloyed, and different copper alloy components are used on the contact surface with air on the surface and the contact surface with the organic substrate at the bottom layer, so as to completely prevent the copper metal layer from being oxidized, thereby meeting the environmental weather resistance of the electromagnetic shielding film.

[0050] The copper alloy Cu 85 The preparation method of Ni8Ti5Cr2 includes the following steps: Weigh pure metal particles by mass percentage, Cu is 85%, Ni is 8%, Ti is 5%, Cr is 2%, and the purity is not less than 99.99%. Mix the four kinds of pure metal particles evenly; put the evenly mixed pure metal particles into a vacuum melting furnace for melting, the melting temperature is 1500 °C, and the melting time is 3 h to form copper alloy Cu 85Ni8Ti5Cr2。

[0051] The copper alloy Cu 83 The preparation method of Ni8Ti5Cr2V2 comprises the following steps: Weigh pure metal particles by mass percentage, where Cu is 83%, Ni is 8%, Ti is 5%, Cr is 2%, and V is 2%, and the purity is not less than 99.99%. Mix the five kinds of pure metal particles evenly; Put the evenly mixed pure metal particles into a vacuum melting furnace for melting. The melting temperature is 1500 °C and the melting time is 3 h to form the copper alloy Cu 83 Ni8Ti5Cr2V2。

[0052] The thickness of the transparent film substrate is 50 μm. The thicknesses of the first low refractive index film layer, the first high refractive index film layer, the second low refractive index film layer, the second high refractive index film layer, the third low refractive index film layer, the third high refractive index film layer, and the fourth low refractive index film layer are 195 nm, 18 nm, 35 nm, 120 nm, 25 nm, 15 nm, and 60 nm respectively.

[0053] The thickness of the first metal mesh grid electromagnetic shielding layer is 0.75 times that of the second metal mesh grid electromagnetic shielding layer, that is, the thickness of the first metal mesh grid electromagnetic shielding layer is 450 nm and the thickness of the second metal mesh grid electromagnetic shielding layer is 600 nm.

[0054] Both layers of the metal mesh grid electromagnetic shielding layer are hollow mesh grid structures composed of periodic hexagons. In the first metal mesh grid electromagnetic shielding layer, the side length of the hexagon is 30 times the line width, that is, the side length of the hexagon is 300 μm and the line width of the side length is 10 μm; In the second metal mesh grid electromagnetic shielding layer, the side length of the hexagon is 30 times the line width, that is, the side length of the hexagon is 240 μm and the line width of the side length is 8 μm.

[0055] This embodiment also provides a preparation method of a high transmittance anti-glare electromagnetic shielding film, which is applied to the above high transmittance anti-glare electromagnetic shielding film and comprises the following steps in sequence:

[0056] Step 1: Use vacuum sputtering coating technology to sputter the copper alloy Cu 85 Ni8Ti5Cr2 on the upper surface of the transparent film substrate;

[0057] Step 2: Spin-coat photoresist on the upper surface of the copper alloy Cu 85 Ni8Ti5Cr2, put it into an oven for baking; After baking is completed, use laser direct writing technology to expose the preset mesh grid pattern, put it into the oven again for baking to cure the photoresist. After curing is completed, put it into a sodium hydroxide solution for development; Put the copper alloy film with the mesh grid pattern into a copper chloride solution for etching. After etching is completed, put it into acetone to remove the copper alloy Cu85 Photoresist on the surface of Ni8Ti5Cr2 to form the first metal mesh grid electromagnetic shielding layer;

[0058] Step 3: Use vacuum sputtering coating technology to sequentially sputter the first low refractive index film layer, the first high refractive index film layer, the second low refractive index film layer, the second high refractive index film layer, the third low refractive index film layer, the third high refractive index film layer, and the fourth low refractive index film layer on the upper surface of the first metal mesh grid electromagnetic shielding layer to form an anti-glare, anti-reflection, and anti-reflection enhancement layer;

[0059] Step 4: Use vacuum sputtering coating technology to sputter copper alloy Cu 83 Ni8Ti5Cr2V2 on the upper surface of the anti-glare, anti-reflection, and anti-reflection enhancement layer;

[0060] Step 5: Spin-coat photoresist on the upper surface of copper alloy Cu 83 Ni8Ti5Cr2V2, and place it in an oven for baking; after baking is completed, use laser direct writing technology to expose the preset mesh grid pattern, place it in the oven again for baking to cure the photoresist, and after curing is completed, place it in a sodium hydroxide solution for development; immerse the entire copper alloy film with the mesh grid pattern in a copper chloride solution for etching, and after etching is completed, place it in acetone to remove the photoresist on the surface of copper alloy Cu 83 Ni8Ti5Cr2V2 to form the second metal mesh grid electromagnetic shielding layer. At this time, a high transmittance anti-glare electromagnetic shielding film can be obtained.

[0061] In Step 1, when sputtering copper alloy Cu 85 Ni8Ti5Cr2, the sputtering pressure is 0.2 Pa, the sputtering power is 120 W, and the sputtering gas is pure argon.

[0062] In Step 2, the photoresist used is AZ5214, and the spin coating rate is 3000 r / min; baking is performed before and after exposing the mesh grid pattern, the baking temperature is 110 °C, and the baking time is 40 min; the concentration of sodium hydroxide (NaOH) solution is 0.1 mol / L; the concentration of copper chloride (CuCl2) solution is 0.5 mol / L, the etching temperature is room temperature, and the etching time is 4 min.

[0063] In Step 3, the sputtering gas pressure of the first low refractive index thin film layer, the second low refractive index thin film layer, the third low refractive index thin film layer, and the fourth low refractive index thin film layer is 0.3 Pa, the sputtering power is 200 W, and the sputtering gas is pure argon. The sputtering gas pressure of the first high refractive index thin film layer and the third high refractive index thin film layer is 0.3 Pa, the sputtering power is 230 W, and the sputtering gas is pure argon; for the second high refractive index thin film layer, i.e., the indium tin oxide thin film layer, the sputtering gas pressure is 0.3 Pa, the sputtering power is 120 W, and the sputtering gas is a mixture of argon and oxygen, where the mass percentage of argon in the mixture is 97.5% and the mass percentage of oxygen in the mixture is 2.5%.

[0064] In Step 4, when sputtering the copper alloy Cu 83 Ni8Ti5Cr2V2, the sputtering gas pressure is 0.2 Pa, the sputtering power is 150 W, and the sputtering gas is pure argon.

[0065] In Step 5, the photoresist used is AZ5214, and the spin coating rate is 3000 r / min; baking is performed before and after exposing the grating pattern, the baking temperature is 110 °C, and the baking time is 40 min; the concentration of the sodium hydroxide (NaOH) solution is 0.1 mol / L; the concentration of the copper chloride (CuCl2) solution is 0.5 mol / L, the etching temperature is room temperature, and the etching time is 4 min.

[0066] The high transmittance anti-glare electromagnetic shielding film and its preparation method of this embodiment have a simple structure and convenient operation. The prepared electromagnetic shielding film has high electromagnetic shielding effectiveness, low visible light reflectivity, and the electromagnetic shielding performance is mainly absorption-based, with excellent stealth performance.

[0067] The electromagnetic shielding film prepared in this embodiment has an electromagnetic shielding effectiveness of 67 dB at 2 - 18 GHz, an electromagnetic wave absorbing effectiveness of 53 dB, a visible light (380 - 780 nm) transmittance of 92%, and a visible light reflectivity of 4.5%.

[0068] Example 2:

[0069] According to another preferred embodiment of the high transmittance anti-glare electromagnetic shielding film of the present invention, its thin film structure, the materials used for each layer, the preparation method, the design principle, the beneficial effects, etc. are basically the same as those of Example 1, except that:

[0070] The material of the transparent thin film substrate is plexiglass. The copper alloy Cu 85 Ni8Ti5Cr2 and the copper alloy Cu 83 In the preparation methods of Ni8Ti5Cr2V2, the melting temperature is 1450 °C and the melting time is 2 h.

[0071] The thickness of the transparent thin film substrate is 125 μm. The thicknesses of the first low refractive index thin film layer, the first high refractive index thin film layer, the second low refractive index thin film layer, the second high refractive index thin film layer, the third low refractive index thin film layer, the third high refractive index thin film layer, and the fourth low refractive index thin film layer are 200 nm, 20 nm, 40 nm, 125 nm, 30 nm, 20 nm, and 65 nm respectively.

[0072] The thickness of the first metal mesh electromagnetic shielding layer is 0.85 times that of the second metal mesh electromagnetic shielding layer, that is, the thickness of the first metal mesh electromagnetic shielding layer is 493 nm, and the thickness of the second metal mesh electromagnetic shielding layer is 580 nm.

[0073] In the first metal mesh electromagnetic shielding layer, the side length of the hexagon is 33 times the line width, that is, the side length of the hexagon is 396 μm, and the line width of the side length is 12 μm; in the second metal mesh electromagnetic shielding layer, the side length of the hexagon is 34 times the line width, that is, the side length of the hexagon is 340 μm, and the line width of the side length is 10 μm.

[0074] In this embodiment, the preparation method of the anti-glare electromagnetic shielding film with high transmittance includes the following main parameters:

[0075] In step one, when sputtering the copper alloy Cu 85 Ni8Ti5Cr2, the sputtering pressure is 0.4 Pa, the sputtering power is 100 W, and the sputtering gas is pure argon.

[0076] In step two, the photoresist used is AZ5214, and the spin coating rate is 3500 r / min; baking is performed before and after exposing the mesh pattern, the baking temperature is 125 °C, and the baking time is 30 min; the concentration of the sodium hydroxide (NaOH) solution is 0.3 mol / L; the concentration of the copper chloride (CuCl2) solution is 0.6 mol / L, the etching temperature is room temperature, and the etching time is 3 min.

[0077] In step three, the sputtering pressures of the first low refractive index thin film layer, the second low refractive index thin film layer, the third low refractive index thin film layer, and the fourth low refractive index thin film layer are all 0.4 Pa, the sputtering powers are all 150 W, and the sputtering gases are all pure argon. The sputtering pressures of the first high refractive index thin film layer and the third high refractive index thin film layer are all 0.4 Pa, the sputtering powers are all 200 W, and the sputtering gases are all pure argon; for the second high refractive index thin film layer, that is, the indium tin oxide thin film layer, the sputtering pressure is 0.4 Pa, the sputtering power is 100 W, and the sputtering gas is a mixture of argon and oxygen, where the mass percentage of argon in the mixture is 97.5%, and the mass percentage of oxygen in the mixture is 2.5%.

[0078] In step four, sputter the copper alloy Cu 83When Ni8Ti5Cr2V2, the sputtering pressure is 0.4 Pa, the sputtering power is 120 W, and the sputtering gas is pure argon.

[0079] In step five, the photoresist used is AZ5214, and the spin coating rate is 3500 r / min; baking is carried out before and after exposing the grating pattern, the baking temperature is 125 °C, and the baking time is 30 min; the concentration of sodium hydroxide (NaOH) solution is 0.3 mol / L; the concentration of copper chloride (CuCl2) solution is 0.6 mol / L, the etching temperature is room temperature, and the etching time is 3 min.

[0080] The electromagnetic shielding film prepared in this example has an electromagnetic shielding effectiveness of 75 dB in the range of 2 - 18 GHz, an electromagnetic wave absorption effectiveness of 56 dB, a visible light (380 - 780 nm) transmittance of 93%, and a visible light reflectance of 4.1%.

[0081] Example three:

[0082] According to another preferred embodiment of the anti - glare electromagnetic shielding film with high transmittance of the present invention, its film structure, materials used for each layer, preparation method, design principle, beneficial effects, etc. are basically the same as those in Example one, except that:

[0083] The material of the transparent film substrate is inorganic glass. The copper alloy Cu 85 Ni8Ti5Cr2 and the copper alloy Cu 83 In the preparation methods of Ni8Ti5Cr2V2, the melting temperature is 1480 °C and the melting time is 2.5 h.

[0084] The thickness of the transparent film substrate is 90 μm. The thicknesses of the first low - refractive - index film layer, the first high - refractive - index film layer, the second low - refractive - index film layer, the second high - refractive - index film layer, the third low - refractive - index film layer, the third high - refractive - index film layer, and the fourth low - refractive - index film layer are 198 nm, 19 nm, 37 nm, 122 nm, 28 nm, 17 nm, and 62 nm respectively.

[0085] The thickness of the first metal mesh electromagnetic shielding layer is 0.8 times that of the second metal mesh electromagnetic shielding layer, that is, the thickness of the first metal mesh electromagnetic shielding layer is 400 nm, and the thickness of the second metal mesh electromagnetic shielding layer is 500 nm.

[0086] In the first metal mesh electromagnetic shielding layer, the side length of the hexagon is 28 times the line width, that is, the side length of the hexagon is 364 μm, and the line width of the side length is 13 μm; in the second metal mesh electromagnetic shielding layer, the side length of the hexagon is 25 times the line width, that is, the side length of the hexagon is 300 μm, and the line width of the side length is 12 μm.

[0087] In this embodiment, the preparation method of the anti-glare electromagnetic shielding film with high transmittance includes the following main parameters:

[0088] In step one, when sputtering copper alloy Cu 85 Ni8Ti5Cr2, the sputtering pressure is 0.3 Pa, the sputtering power is 110 W, and the sputtering gas is pure argon.

[0089] In step two, the photoresist used is AZ5214, and the spin coating rate is 3300 r / min; baking is performed before and after exposing the grid pattern, the baking temperature is 118 °C, and the baking time is 35 min; the concentration of sodium hydroxide (NaOH) solution is 0.2 mol / L; the concentration of copper chloride (CuCl2) solution is 0.55 mol / L, the etching temperature is room temperature, and the etching time is 3.5 min.

[0090] In step three, the sputtering pressures of the first low refractive index film layer, the second low refractive index film layer, the third low refractive index film layer, and the fourth low refractive index film layer are all 0.35 Pa, the sputtering powers are all 180 W, and the sputtering gases are all pure argon. The sputtering pressures of the first high refractive index film layer and the third high refractive index film layer are all 0.35 Pa, the sputtering powers are all 215 W, and the sputtering gases are all pure argon; for the second high refractive index film layer, that is, the indium tin oxide film layer, the sputtering pressure is 0.35 Pa, the sputtering power is 110 W, and the sputtering gas is a mixture of argon and oxygen, where the mass percentage of argon in the mixture is 97.5%, and the mass percentage of oxygen in the mixture is 2.5%.

[0091] In step four, when sputtering copper alloy Cu 83 Ni8Ti5Cr2V2, the sputtering pressure is 0.3 Pa, the sputtering power is 135 W, and the sputtering gas is pure argon.

[0092] In step five, the photoresist used is AZ5214, and the spin coating rate is 3300 r / min; baking is performed before and after exposing the grid pattern, the baking temperature is 118 °C, and the baking time is 35 min; the concentration of sodium hydroxide (NaOH) solution is 0.2 mol / L; the concentration of copper chloride (CuCl2) solution is 0.55 mol / L, the etching temperature is room temperature, and the etching time is 3.5 min.

[0093] The electromagnetic shielding film prepared in this embodiment has an electromagnetic shielding effectiveness of 53 dB at 2 - 18 GHz, an electromagnetic wave absorption effectiveness of 42 dB, a visible light (380 - 780 nm) transmittance of 91%, and a visible light reflectance of 4.9%.

[0094] Special Note: The technical solution of the present invention involves many parameters. It is necessary to comprehensively consider the synergistic effects among various parameters in order to obtain the beneficial effects and remarkable progress of the present invention. Moreover, the value ranges of each parameter in the technical solution are obtained through a large number of experiments. For each parameter and the mutual combination of various parameters, the inventor has recorded a large amount of experimental data. Due to space limitations, the specific experimental data are not disclosed here.

[0095] It is not difficult for those skilled in the art to understand that the high transmittance anti-glare electromagnetic shielding film and its preparation method of the present invention include any combination of the above-mentioned invention content, specific implementation manner part of the present invention specification and each part shown in the drawings. Due to space limitations and to make the specification concise, the various solutions formed by these combinations are not described one by one. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high transmittance anti-glare electromagnetic shielding film, comprising a transparent thin film substrate, an anti-glare, anti-reflection and anti-reflection enhancement layer, and a metal mesh electromagnetic shielding layer, characterized in that: The metal mesh grid electromagnetic shielding layer includes a first metal mesh grid electromagnetic shielding layer and a second metal mesh grid electromagnetic shielding layer; the arrangement order of the transparent thin film substrate, the anti-glare, anti-reflection and anti-reflection enhancement layer, and the metal mesh grid electromagnetic shielding layer from bottom to top is the transparent thin film substrate, the first metal mesh grid electromagnetic shielding layer, the anti-glare, anti-reflection and anti-reflection enhancement layer, and the second metal mesh grid electromagnetic shielding layer; The material of the first metal mesh electromagnetic shielding layer is copper alloy Cu 85 Ni8Ti5Cr2, and its preparation method: Weigh four kinds of pure metal particles according to mass percentage and mix them evenly, where Cu is 85%, Ni is 8%, Ti is 5%, and Cr is 2%; Put the evenly mixed pure metal particles into a vacuum melting furnace for melting, the melting temperature is 1450 - 1500 °C, and the melting time is 2 - 3 h; The material of the second metal mesh electromagnetic shielding layer is copper alloy Cu 83 Ni8Ti5Cr2V2. Its preparation method: Weigh five kinds of pure metal particles according to the mass percentage and mix them evenly, where Cu is 83%, Ni is 8%, Ti is 5%, Cr is 2%, and V is 2%; put the evenly mixed pure metal particles into a vacuum melting furnace for melting, the melting temperature is 1450 - 1500 °C, and the melting time is 2 - 3 h.

2. The high transmittance anti-glare electromagnetic shielding film according to claim 1, characterized in that: The material of the transparent thin film substrate is any one of polyethylene terephthalate, inorganic glass, and organic glass.

3. The high transmittance anti-glare electromagnetic shielding film according to claim 1, characterized in that: The anti-glare, anti-reflection and anti-reflection enhancement layer sequentially includes a first low refractive index thin film layer, a first high refractive index thin film layer, a second low refractive index thin film layer, a second high refractive index thin film layer, a third low refractive index thin film layer, a third high refractive index thin film layer, and a fourth low refractive index thin film layer from bottom to top.

4. The high transmittance anti-glare electromagnetic shielding film according to claim 3, characterized in that: The materials of the first low refractive index thin film layer, the second low refractive index thin film layer, the third low refractive index thin film layer, and the fourth low refractive index thin film layer are silicon dioxide, magnesium fluoride, silicon dioxide, and magnesium fluoride respectively.

5. The high transmittance anti-glare electromagnetic shielding film according to claim 4, characterized in that: The materials of the first high refractive index thin film layer, the second high refractive index thin film layer, and the third high refractive index thin film layer are tantalum pentoxide, indium tin oxide, and hafnium dioxide respectively.

6. The high transmittance anti-glare electromagnetic shielding film according to claim 2, characterized in that: The thickness of the transparent thin film substrate is 50 - 125 μm.

7. The high transmittance anti-glare electromagnetic shielding film according to claim 3, characterized in that: The thicknesses of the first low refractive index thin film layer, the first high refractive index thin film layer, the second low refractive index thin film layer, the second high refractive index thin film layer, the third low refractive index thin film layer, the third high refractive index thin film layer, and the fourth low refractive index thin film layer are 195 - 200 nm, 18 - 20 nm, 35 - 40 nm, 120 - 125 nm, 25 - 30 nm, 15 - 20 nm, and 60 - 65 nm respectively.

8. The high transmittance anti-glare electromagnetic shielding film according to claim 1, characterized in that: The thickness of the first metal mesh grid electromagnetic shielding layer is 400 - 500 nm, and the thickness of the second metal mesh grid electromagnetic shielding layer is 500 - 600 nm.

9. A method for preparing a high transmittance anti-glare electromagnetic shielding film, characterized in that: For preparing the high transmittance anti-glare electromagnetic shielding film described in any one of claims 1 - 8, the following steps are included in sequence, Step 1: Sputter copper alloy Cu 85 Ni8Ti5Cr2 on the upper surface of a transparent thin film substrate by using vacuum sputtering coating technology; Step 2: Spin-coat photoresist on the upper surface of the copper alloy Cu 85 Ni8Ti5Cr2, place it in an oven for baking; after baking is completed, use laser direct writing technology to expose a preset grid pattern, and then place it in the oven for baking again to cure the photoresist. After curing is completed, place it in a sodium hydroxide solution for development; place the copper alloy film with the grid pattern in a copper chloride solution for etching. After etching is completed, place it in acetone to remove the photoresist on the surface of the copper alloy Cu 85 Ni8Ti5Cr2 to form a first metal grid electromagnetic shielding layer; Step three: Adopt vacuum sputtering coating technology to sequentially sputter deposit the first low refractive index thin film layer, the first high refractive index thin film layer, the second low refractive index thin film layer, the second high refractive index thin film layer, the third low refractive index thin film layer, the third high refractive index thin film layer, and the fourth low refractive index thin film layer on the upper surface of the first metal mesh grid electromagnetic shielding layer to form an anti-glare, anti-reflection and anti-reflection enhancement layer; Step 4: Sputter copper alloy Cu on the upper surface of the anti-glare, anti-reflection and anti-transmission layer by using vacuum sputtering coating technology 83 Ni8Ti5Cr2V2; Step Five: Spin-coat photoresist on the upper surface of the copper alloy Cu 83 Ni8Ti5Cr2V2, and place it in an oven for baking; after baking is completed, use laser direct writing technology to expose the preset grid pattern, and then place it in the oven for baking again to cure the photoresist. After curing is completed, place it in a sodium hydroxide solution for development; place the copper alloy film with the grid pattern as a whole in a copper chloride solution for etching. After etching is completed, place it in acetone to remove the photoresist on the surface of the copper alloy Cu 83 Ni8Ti5Cr2V2 to form a second metal grid electromagnetic shielding layer, and at this time, a high-transmittance anti-glare electromagnetic shielding film can be obtained.

10. The method for preparing a high transmittance anti-glare electromagnetic shielding film according to claim 9, characterized in that: In Step 1, sputter copper alloy Cu 85 When Ni8Ti5Cr2, the sputtering pressure is 0.2 - 0.4 Pa, the sputtering power is 100 - 120 W, and the sputtering gas is pure argon; In step two, the photoresist used is AZ5214, and the spin coating rate is 3000 - 3500 r / min; baking is carried out before and after exposing the grid pattern, the baking temperature is 110 - 125 °C, and the baking time is 30 - 40 min; the concentration of the sodium hydroxide solution is 0.1 - 0.3 mol / L; the concentration of the copper chloride solution is 0.5 - 0.6 mol / L, the etching temperature is room temperature, and the etching time is 3 - 4 min; In Step 3, the sputtering gas pressure of the first low refractive index thin film layer, the second low refractive index thin film layer, the third low refractive index thin film layer, and the fourth low refractive index thin film layer is 0.3 - 0.4 Pa, the sputtering power is 150 - 200 W, and the sputtering gas is pure argon; the sputtering gas pressure of the first high refractive index thin film layer and the third high refractive index thin film layer is 0.3 - 0.4 Pa, the sputtering power is 200 - 230 W, and the sputtering gas is pure argon; For the second high refractive index thin film layer, i.e., the indium tin oxide thin film layer, the sputtering gas pressure is 0.3 - 0.4 Pa, the sputtering power is 100 - 120 W, and the sputtering gas is a mixture of argon and oxygen, where the mass percentage of argon in the mixture is 97.5% and the mass percentage of oxygen in the mixture is 2.5%; In Step 4, sputter copper alloy Cu 83 When Ni8Ti5Cr2V2, the sputtering pressure is 0.2 - 0.4 Pa, the sputtering power is 120 - 150 W, and the sputtering gas is pure argon; In Step 5, the photoresist used is AZ5214, and the spin coating rate is 3000 - 3500 r / min; baking is performed before and after exposing the grating pattern, the baking temperature is 110 - 125 °C, and the baking time is 30 - 40 min; the concentration of the sodium hydroxide solution is 0.1 - 0.3 mol / L; the concentration of the copper chloride solution is 0.5 - 0.6 mol / L, the etching temperature is room temperature, and the etching time is 3 - 4 min.

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