CN106413360B

CN106413360B - Double-layer metal mesh electromagnetic shielding optical window with graphene mesh interlayer

Info

Publication number: CN106413360B
Application number: CN201510448955.8A
Authority: CN
Inventors: 谭久彬; 陆振刚; 王赫岩
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2015-07-28
Filing date: 2015-07-28
Publication date: 2020-04-28
Anticipated expiration: 2035-07-28
Also published as: CN106413360A

Abstract

Double-deck metal net bars electromagnetic shield optical window with graphite alkene net bars intermediate layer belongs to optics transparency electromagnetic shield technical field, and this electromagnetic shield optical window utilizes graphite alkene net bars film to have different printing opacity and the microwave shielding characteristic that shows when different mesh unit open area ratio, with graphite alkene net bars film's low reflection and partial absorption microwave characteristic and the high-pass through strong electromagnetic reflection characteristic of electrically conductive film organic combination, constitutes multilayer structure: the transparent reflection layer is formed by assembling a first transparent absorption layer, a transparent medium A, a metal mesh grid A, a transparent medium B, a second transparent absorption layer, a transparent medium C and a metal mesh grid B which are sequentially overlapped and arranged in parallel, wherein the first transparent absorption layer is formed by N layers of graphene mesh grid films separated by the transparent medium, the second transparent absorption layer is formed by 1-6 layers of graphene mesh grid films separated by the transparent medium, and the metal mesh grid A and the metal mesh grid B form a transparent reflection layer; the invention solves the problem that strong electromagnetic shielding, low electromagnetic reflection and high light transmission of the existing transparent electromagnetic shielding technology can not be considered at the same time, and has the characteristics of strong electromagnetic shielding, low electromagnetic reflection and high light transmission.

Description

Double-layer metal mesh electromagnetic shielding optical window with graphene mesh interlayer

Technical Field

The invention belongs to the field of electromagnetic shielding of optical transparent parts, and particularly relates to a double-layer metal mesh electromagnetic shielding optical window with a graphene mesh interlayer.

Background

With the development of broadcasting, television, wireless communication technology and microwave technology, radio frequency equipment is equipped in a large number in various places where people move, the frequency spectrum range is continuously widened, and the intensity is multiplied, so that the radio frequency equipment not only causes interference to electronic equipment, but also threatens human health. The invisible electromagnetic pollution directly acts on machines or human bodies, is an invisible killer with serious harm, and becomes the fifth largest pollution following atmospheric pollution, water pollution, solid waste pollution and noise pollution. Electromagnetic shielding (including absorption and reflection) is a major measure for preventing and treating electromagnetic pollution, and in recent years, electromagnetic shielding technology has received much attention. The electromagnetic shielding, namely transparent electromagnetic shielding, which is required in visual observation occasions is always a difficult point and a hot point, and the application of the electromagnetic shielding, namely transparent electromagnetic shielding, comprises a medical electromagnetic isolation room observation window, a communication equipment transparent electromagnetic shielding element, an aerospace equipment optical window, an advanced optical instrument optical window, a confidential facility electromagnetic leakage prevention optical window, a liquid crystal display screen, a mobile phone touch screen, a vehicle-mounted transparent antenna and the like.

At present, the difficulty of realizing transparent electromagnetic shielding mainly lies in that most of traditional wave-absorbing materials are opaque or have poor transparency, and the transparency and the conductive shielding capability of the reflection transparent shielding technology based on transparent conductive materials or devices are mutually restricted, so that high transparency and strong electromagnetic shielding are difficult to realize simultaneously. In addition, the conductive reflective transparent shielding technology reflects electromagnetic radiation back to the space, which causes secondary pollution to the space environment and is not beneficial to the thorough prevention and treatment of electromagnetic pollution.

The transparent metal oxide film mainly made of indium tin oxide is widely applied to the visible light transparent occasions, but the light transmission waveband of the transparent metal oxide film is narrow, and the shielding capacity is not strong although the microwave shielding waveband is wide. The nano silver conductive network film can realize about 90% of light transmittance, but the nano silver wires have inevitable contact resistance, and particularly, the nano silver wires are very thin and sparse when the light transmittance is high, so that the surface resistance of the nano silver wires is high, and the shielding efficiency is further reduced. The band-pass type frequency selective surface adopts a periodic resonance unit structure, can highly reflect interference microwaves outside an operating frequency band, but has poor light transmission and is difficult to realize a wide light transmission band. Therefore, the technical schemes can not meet the requirements of the electromagnetic shielding optical window on high light transmission and strong microwave shielding capability.

In contrast, the metal mesh grid with the period from millimeter to submillimeter is much shorter than the interference electromagnetic wavelength and much longer than the optical wavelength, so that the low-frequency broadband electromagnetic shielding can be realized, and meanwhile, the higher light transmittance of the visible light and the infrared band can be ensured. Therefore, the metal mesh grid with millimeter and sub-millimeter period is widely applied in the technical field of optical window electromagnetic shielding due to good transparent conductive performance:

1. patent 200810063988.0 entitled "an electromagnetic shielding optical window with double-layer square metal grid structure" describes an electromagnetic shielding optical window formed by placing square metal grids or metal wire nets with the same structural parameters in parallel on two sides of an optical window or a transparent substrate, which greatly improves the electromagnetic shielding efficiency.

2. Patent 200810063987.6 entitled "electromagnetic shielding optical window with double-layer circular ring metal grid structure" describes an electromagnetic shielding optical window formed by two layers of circular ring metal grids loaded on two sides of the optical window, which solves the problem that high light transmittance and strong electromagnetic shielding efficiency cannot be simultaneously considered.

3. Patent 201410051497.X "multi-period master-slave nested circular ring array electromagnetic shielding optical window with concentric circular rings" describes a metal mesh grid structure nested with the concentric circular rings and used for realizing the electromagnetic shielding function of the optical window, wherein the metal mesh grid structure enables stray light caused by high-level diffraction to be homogenized to a certain extent, and the influence of the mesh grid on the imaging quality of the optical window is reduced.

4. Patent 201410051496.5 entitled "electromagnetic shielding optical window with double-layer staggered multicycle metal ring nested array" describes an electromagnetic shielding optical window formed by two layers of staggered metal grids, which significantly reduces the nonuniformity of the grid diffraction light intensity distribution and the influence on imaging.

Patent 200810063988.0 and patent 200810063987.6 all adopt double-deck metal net bars parallel to place in the both sides of light window transparent substrate or substrate and constitute, and two-deck metal net bars have the same unit appearance and structural parameter, through the interval of optimizing two-layer net bars, have improved electromagnetic shielding efficiency. Patent 201410051497.X proposes a mesh grid structure with a master-slave nested circular ring array of multi-period concentric circular rings, which realizes the depth homogenization of high-order diffraction and reduces the influence on the imaging quality. Patent 201410051496.5 makes stray light distribution more even through the selection of double-layer grid stagger angle, and has less influence on imaging quality. In the above patents, the metal mesh grid (or the metal wire mesh) is used as a core device for microwave shielding, so that a better electromagnetic shielding effect and light transmittance can be realized, but when the metal is used as a reflective electromagnetic shielding material, a reflected radio frequency signal can cause secondary pollution to the space environment, and the prevention and treatment of electromagnetic pollution is not facilitated thoroughly.

Carbon materials play a very important role in many areas of modern technology, among the many allotropes of carbon, graphene is a very typical material, graphene being formed from carbon atoms in sp₂The hexagonal honeycomb lattice planar thin film formed by the hybrid tracks is a two-dimensional material with the thickness of only one carbon atom, has multiple excellent properties, one of the outstanding properties is excellent transparent conductivity and certain microwave absorption performance, so that the graphene has high application value in the field of transparent electromagnetic shielding:

5. U.S. Pat. No. 20130068521, "graphene preparation method using graphene prepared by Chemical Vapor Deposition (CVD)" is loaded on a metal plate or a polymer substrate to realize Electromagnetic shielding, and compared with a metal plate or a polymer substrate which is not loaded with graphene, the Electromagnetic shielding efficiency of the whole structure is improved after the graphene is loaded.

6. Patent 201310232829. X "graphene-based structures and methods for shielding electromagnetic radiation" describes an electromagnetic shielding structure for shielding electromagnetic radiation having a frequency greater than 1 mhz, the structure being composed of one or more layers of graphene, at least one layer of graphene being doped with a dopant.

7. Patent 201420099425.8 "a transparent electromagnetic shielding film based on graphene film" describes a transparent electromagnetic shielding film with nano-silver wires arranged between a transparent substrate and a graphene film, wherein the nano-silver wires act as a charge bridge to increase the conductivity of the whole electromagnetic shielding film and improve the shielding efficiency.

8. James M. Tour et al, Rice University (Rice University) of America, used photolithography to prepare metal grids with line width of 5 μm, and transferred single-layer Graphene on the surface to make Graphene-metal grid mixed conductive Films (James M. Tour et al, "Rational Design of Hybrid Graphene Films for High-Performance transmission Electrodes". ACS Nano, 2011, 5 (8): 6472-6479), which can realize 90% transmittance and 20 Ω/sq sheet resistance.

9. Seul Ki Hong et al, Korea scientific and technical institute (KAIST), reported that the shielding efficiency of single-layer graphene was 2.27dB (Hong S K et al, "Electromagnetic interference shielding efficiency of monolayer graphene". Nanotechnology, 2012, 23 (45): 455704), with absorption and reflection losses of-4.38 dB and-13.66 dB, respectively.

10. Kim S of the University of Korea (Sungkyunkwan University) and Myeong-Gi, et al of the Korea three-star Motor company (Samsung Electro-Mechanics) use a polyetherimide/redox method to prepare a Graphene (PEI/RGO) laminate structure to achieve Electromagnetic Shielding (Kim S, et al, "Electromagnetic Interference (EMI) Transmission Shield of Reduced Graphene Oxide (RGO) Electromagnetic Interference disposed". AppACS plied materials & interfaces, Electromagnetic Shielding 2014, 6 (20): 17647 17653), the efficiencies of the double-layer PEI/RGO and single-layer PEI/RGO laminates are 6.37 and 3.09dB, respectively, and the absorption loss accounts for 96% and 92% of the total efficiency, respectively.

11. Hanjie et al, Harbin university of Industrial science, uses a copper mesh as a sacrificial layer, and prepares a plurality of graphene meshes (Han J, et al, "isolated-transmissive film based on a modulated graphene network fabric for electronic shielding". Carbon, 2015, 87: 206-type 214) by Chemical Vapor Deposition (CVD), respectively achieving 70.85% Infrared transmittance and 12.86dB shielding efficiency, and achieving 87.85% Infrared transmittance and 4dB shielding efficiency. And the graphene grid electromagnetic shielding is also dominated by absorption.

According to the scheme, the graphene is used for electromagnetic shielding, and a certain electromagnetic shielding effect can be achieved. US20130068521 uses graphene as a core device of an electromagnetic shielding device, and transfers a whole large-area graphene onto substrates such as metal and polymer by a roll-to-roll graphene transfer method, so as to achieve an excellent electromagnetic shielding effect, but the electromagnetic shielding device does not have transparency. Patent 201310232829. X "graphene-based structure and method for shielding electromagnetic radiation" uses a graphene thin film as a main body of an electromagnetic shielding structure, and at least one layer of the graphene thin film is doped to improve the electromagnetic shielding efficiency, but the doping affects the light transmittance of the whole structure. Patent 201420099425.8, "a transparent electromagnetic shielding film based on graphene thin film", utilizes nano-silver wires to increase the conductivity of the graphene thin film and increase the reflection loss to achieve the improvement of the electromagnetic shielding efficiency, but the main contribution of the electromagnetic shielding is caused by reflection. In the document 8, the graphene film is loaded on the metal mesh to form a structure in which the graphene and the metal mesh are tightly attached to each other, so that the conductivity of the metal mesh is improved, and meanwhile, the light transmittance reaches 91%, but the electromagnetic shielding of the structure is mainly reflected. The research results in the above-mentioned document 9 indicate that although the shielding efficiency of graphene increases greatly as the number of layers increases, the absorption loss increases little, and the light transmittance is lost by 2.3% per one layer of graphene, making it difficult to achieve high light transmittance, low reflection, and strong electromagnetic shielding at the same time with this structure. In the above document 10, the graphene thin film (RGO) and Polyetherimide (PEI) laminated structure prepared by the redox method realizes electromagnetic shielding, and the shielding mainly involves absorption loss, but the shielding efficiency of the double-layer PEI/RGO structure is only 6.37dB, and the light transmittance is only 62%, and it is difficult to realize both strong electromagnetic shielding and high light transmittance. The document 11 only adopts a graphene grid structure, and the shielding efficiency is low, and the strong shielding efficiency and the high light transmittance cannot be obtained at the same time.

In a word, in the prior electromagnetic shielding technology, a method mainly based on reflection-type electromagnetic shielding is easy to cause secondary electromagnetic pollution; in the electromagnetic shielding method with absorption loss, either the light transmittance is not high or the electromagnetic shielding efficiency is not strong, so that it is difficult to realize high transparency and strong electromagnetic shielding at the same time.

Disclosure of Invention

The invention aims to overcome the defects of the existing transparent electromagnetic shielding technology, in particular to the problems that the transparency and the conductive shielding capability of the existing reflective transparent shielding technology are mutually restricted, the high light transmittance and the strong microwave shielding efficiency are difficult to be considered, and electromagnetic leakage and secondary pollution are caused by reflected electromagnetic signals.

The purpose of the invention is realized as follows: the double-layer metal mesh electromagnetic shielding optical window with the graphene mesh interlayer is formed by assembling a first transparent absorption layer, a transparent medium A, a metal mesh A, a transparent medium B, a second transparent absorption layer, a transparent medium C and a metal mesh B which are sequentially overlapped and arranged in parallel; the first transparent absorption layer is composed of N layers of graphene grid films separated by transparent media, the second transparent absorption layer is composed of 1-6 layers of graphene grid films separated by transparent media, and the metal grid A and the metal grid B which are arranged in parallel form a transparent reflection layer.

The good effect produced by the invention is mainly focused on realizing the electromagnetic shielding, low electromagnetic reflection and high light transmittance, and the invention comprises the following specific steps:

firstly, electromagnetic shielding with high light transmission and absorption as main functions is realized by utilizing different light transmission and microwave shielding characteristics shown when the graphene grid film has different aperture unit opening area ratios; when the aperture area ratio t of the mesh unit of the graphene grid film is between 0.05 and 0.7, good light transmission and shielding performance can be realized by adjusting the number of layers of the graphene grid film. When the opening area ratio t of the mesh unit of the graphene grid film meets the condition that t is more than or equal to 0.3 and less than or equal to 0.7, the light transmittance which is similar to that of a single-layer graphene film is realized by utilizing the multi-layer graphene grid film, and meanwhile, the shielding performance is improved; when the opening area ratio t of the mesh unit of the graphene grid film meets the condition that t is more than or equal to 0.05 and less than 0.3, the microwave shielding performance similar to that of a single-layer graphene film is realized by utilizing the single-layer graphene grid film, and meanwhile, the light transmittance is improved; meanwhile, the microwave shielding performance of the graphene grid film is mainly microwave absorption.

Secondly, the microwave absorption characteristic of the graphene grid film and the strong microwave reflection characteristic of the double-layer metal grid are organically combined, the double-layer metal grid is used as a basic structure of the transparent reflection layer, compared with a single-layer metal grid, the microwave shielding efficiency and the reflectivity are remarkably improved on the premise that the light transmittance performance is not changed, and strong electromagnetic shielding and reflection of radio frequency radiation can be better realized; the N layers of graphene grid thin film structures separated by transparent media are used as a first transparent absorption layer, so that radio frequency radiation can be partially absorbed and pass through the first transparent absorption layer in a low-reflection mode; the transparent reflecting layer is arranged behind the first transparent absorbing layer, so that strong electromagnetic shielding is realized, microwaves transmitted through the transparent absorbing layer are reflected back to the transparent absorbing layer, and radio-frequency radiation is reflected and absorbed for multiple times; the graphene grid film structure with 1-6 layers separated by transparent media is used as a second transparent absorption layer, the second transparent absorption layer is placed between the double-layer metal grids A, B in parallel, the metal grid A passing through the first layer can be absorbed for multiple times, and due to the strong reflection effect of the metal grid A, B, microwave signals oscillating between the double-layer metal grids are generated, so that the electromagnetic shielding efficiency is greatly improved, and finally, strong electromagnetic shielding with low reflection is realized.

According to the double-layer metal mesh grid laminated structure with the graphene mesh grid interlayer, on one hand, due to the existence of the first transparent absorption layer, the problem that secondary electromagnetic pollution is easily caused by shielding mainly based on reflection when only a metal mesh grid exists is solved; on the other hand, due to the existence of the transparent reflecting layer, and the metal mesh A, B of the transparent reflecting layer is respectively arranged behind the first transparent absorbing layer and the second transparent absorbing layer, microwaves to be shielded are reflected and absorbed for multiple times, and the problem of low shielding efficiency when only the graphene mesh film absorbing layer exists is solved; in addition, the second transparent absorption layer is arranged between the metal grids A, B in parallel, so that radio frequency radiation reflected between the double-layer metal grids can be absorbed for multiple times, and the electromagnetic shielding efficiency is greatly improved; meanwhile, for light waves, the light waves only penetrate through the transparent absorption layer and the transparent reflection layer once, the loss is less, the high light transmission characteristic can be realized, and when the opening area ratio t of the mesh units of the graphene grid film is between 0.05 and 0.7, the graphene grid film has a periodic opening structure, so that the light transmission performance is improved, and the high light transmission characteristic can be realized; and when the double-layer metal mesh grid adopts a mesh grid structure with uniform distribution of diffracted stray light, the influence of the whole laminated structure on the imaging quality is very low.

In conclusion, the invention has the most outstanding effects of strong electromagnetic shielding, low electromagnetic reflection and high light transmittance.

Drawings

Fig. 1 is a schematic cross-sectional view of a double-layer metal mesh electromagnetic shielding light window with a graphene mesh interlayer.

Fig. 2 is a schematic structural diagram of a grid unit arrangement mode of a square-hole graphene grid.

Fig. 3 is a schematic structural diagram of a grid unit arrangement mode of a circular hole graphene grid.

Fig. 4 is a schematic structural diagram of a grid unit arrangement of a grid metal grid.

Fig. 5 is a schematic structural diagram of an arrangement mode of grid units of a circular ring metal grid.

Fig. 6 is a schematic diagram of the arrangement of grid cells of the multi-period micro-ring metal grid.

Fig. 7 is a schematic cross-sectional view of an electromagnetic shielding optical window with a graphene mesh interlayer and a double-layer metal mesh according to an embodiment.

Fig. 8 is a schematic structural diagram of an electromagnetic shielding optical window with a graphene grid interlayer and a double-layer metal grid according to an embodiment.

Description of part numbers in the figures: 1. the protective layer A2, the antireflection film A3, the first transparent absorption layer 4, the transparent medium A5, the metal grid A6, the transparent medium B7, the second transparent absorption layer 8, the transparent medium C9, the metal grid B10, the antireflection film B11, the protective layer B12, the square-hole graphene grid film A13, the transparent medium 14, the square-hole graphene grid film B15 and the square-hole graphene grid film C.

Detailed Description

Embodiments of the invention are described in detail below with reference to the accompanying drawings:

the electromagnetic shielding optical window is formed by assembling a first transparent absorption layer (3), a transparent medium A (4), a metal mesh grid A (5), a transparent medium B (6), a second transparent absorption layer (7), a transparent medium C (8) and a metal mesh grid B (9) which are sequentially overlapped and arranged in parallel; the first transparent absorption layer (3) is composed of N layers of graphene grid films separated by transparent media, the second transparent absorption layer (7) is composed of 1-6 layers of graphene grid films separated by transparent media, and the metal grid A (5) and the metal grid B (9) which are arranged in parallel form a transparent reflection layer; the graphene grid films forming the transparent absorption layers (3) and (7) are formed by graphene films with mesh array structures; the mesh array structure is a two-dimensional array structure formed by periodically arranging mesh units; the mesh units are in the shape of square holes or round holes; the mesh unit size is in the range of submicron to millimeter, and the mesh unit array period is in the range of micron to millimeter; the opening area ratio t of the mesh units is between 0.05 and 0.7; the open area ratio of the mesh unit refers to the ratio of the open area of the mesh unit to the unit area of the array period in one array period.

Arranging a single-layer or multi-layer antireflection film A (2) and a single-layer or multi-layer protective layer A (1) in parallel on the outer side part of the first transparent absorption layer (3); a single-layer or multi-layer antireflection film B (10) and a single-layer or multi-layer protective layer B (11) are sequentially arranged on the outer side part of the metal mesh B (9) in parallel.

When the ratio t of the open area of the mesh unit of the graphene grid film satisfies 0.3 ≦ t ≦ 0.7, the transparent absorption layers (3) and (7) are composed of the graphene grid film in which N layers are separated by the transparent medium, wherein N ≦ 6 { [1/(1-t) ] +1}, and [1/(1-t) ] represents the maximum positive integer of not more than 1/(1-t).

When the ratio t of the open area of the mesh units of the graphene grid film is more than or equal to 0.05 and less than 0.3, the transparent absorption layers (3) and (7) are formed by N graphene grid films separated by transparent media, wherein N is less than or equal to 6.

The metal grids A, B (5, 9) are both composed of two-dimensional plane structures with grid units arranged periodically, the period of the grid units is sub-millimeter to millimeter magnitude, the width of the metal lines is sub-micrometer to micrometer magnitude, and connecting metal for communicating the two metal lines is arranged between the adjacent grid units through metal line overlapping or at the overlapping position.

The distance between the metal mesh grid A (5) and the metal mesh grid B (9) is millimeter magnitude, and the distance is less than 0.25 time of the minimum shielding wavelength.

The number of layers of the graphene grid films forming the first and second transparent absorption layers (3, 7) is single-layer, double-layer or three-layer, and the number of layers of the graphene grid films separated by the transparent medium forming the first and second transparent absorption layers (3, 7) can be the same or different.

The metal grids A, B (5, 9) are made of alloy materials with good conductivity, and the thickness of the alloy is larger than 100 nm.

The transparent reflective layer formed from metal mesh A, B (5, 9) has a light transmission greater than 90%.

The transparent medium A, B, C (4, 6, 8) and the transparent medium manufacturing material for separating the first transparent absorption layer and the second transparent absorption layer (3, 7) from the graphene grid film comprise common glass, quartz glass, infrared materials and transparent resin materials.

According to the double-layer metal mesh electromagnetic shielding optical window with the graphene mesh interlayer, the distance between the double-layer metal mesh A5 and the double-layer metal mesh B9 is in the millimeter order, and compared with a single-layer metal mesh structure, the microwave shielding effect of the electromagnetic shielding optical window can be remarkably improved under the condition that the light transmittance is not changed.

Examples

The electromagnetic shielding optical window is formed by assembling a first transparent absorption layer 3, a transparent medium A4, a metal grid A5, a transparent medium B6, a second transparent absorption layer 7, a transparent medium C8 and a metal grid B9 which are sequentially overlapped and arranged in parallel; the first transparent absorption layer 3 is composed of a single-layer graphene grid film A12, a transparent medium D13 and a single-layer graphene grid film B14 which are sequentially arranged in parallel, the second transparent absorption layer is composed of a single-layer graphene grid film C15, and the metal grid A5 and the metal grid B9 which are arranged in parallel form a transparent reflection layer.

The invention has the technical effects that: when the electromagnetic shielding efficiency of the double-layer metal mesh grid is 29.8dB, the electromagnetic shielding efficiency of the double-layer metal mesh grid is 35.34dB, the absorption loss accounts for 59% of the total shielding energy, strong electromagnetic shielding with absorption as the main is realized, the light transmittance is 88.1%, and the double-layer metal mesh grid still has high light transmittance. The double-layer micro-ring metal mesh grid is used as a transparent reflecting layer, the electromagnetic shielding efficiency is 34.12dB, the absorption loss accounts for 58.5% of the total shielding energy, and the light transmittance is 90.4%. Compared with a simulation result that the double-layer micro-ring metal mesh grid is used as the transparent reflecting layer, the double-layer metal mesh grid electromagnetic shielding optical window with the graphene mesh grid interlayer has the advantages that the microwave shielding performance is remarkably improved under the condition that the light transmittance is sacrificed to a small extent, and the ultra-strong microwave shielding efficiency can be realized.

The invention also corresponds to other embodiments, changes the shape and the structural parameters of the basic unit of the double-layer metal mesh grid in the figure 7 and the arrangement mode of the basic unit, keeps the original arrangement mode of each layer unchanged, and finally can obtain similar effect; on the basis of the first transparent absorption layer composed of two single-layer graphene grids separated from each other in fig. 7, increasing or decreasing the number of single-layer graphene grid films separated by a transparent medium will result in an increase in absorption loss or an increase in light transmittance; can be adjusted correspondingly according to actual needs.

Claims

1. Double-deck metal net bars electromagnetic shield light window with graphite alkene net bars intermediate layer, its characterized in that: the electromagnetic shielding optical window is formed by assembling a first transparent absorption layer (3), a transparent medium A (4), a metal mesh grid A (5), a transparent medium B (6), a second transparent absorption layer (7), a transparent medium C (8) and a metal mesh grid B (9) which are sequentially overlapped and arranged in parallel; the first transparent absorption layer (3) is composed of N layers of graphene grid films separated by transparent media, the second transparent absorption layer (7) is composed of 1-6 layers of graphene grid films separated by transparent media, and the metal grid A (5) and the metal grid B (9) which are arranged in parallel form a transparent reflection layer; the graphene grid films forming the transparent absorption layers (3) and (7) are formed by graphene films with mesh array structures; the mesh array structure is a two-dimensional array structure formed by periodically arranging mesh units; the mesh units are in the shape of square holes or round holes; the mesh unit size is in the range of submicron to millimeter, and the mesh unit array period is in the range of micron to millimeter; the opening area ratio t of the mesh units is between 0.05 and 0.7; the ratio of the open area of the mesh units refers to the ratio of the open area of the mesh units to the area of the units in an array period; when the ratio t of the open area of the mesh unit of the graphene grid film satisfies 0.3 ≦ t ≦ 0.7, the transparent absorption layers (3) and (7) are composed of the graphene grid film with N layers separated by the transparent medium, wherein N ≦ 6 { [1/(1-t) ] +1}, and [1/(1-t) ] represents the maximum positive integer not exceeding 1/(1-t); when the ratio t of the open area of the mesh units of the graphene grid film satisfies 0.05-t <0.3, the transparent absorption layers (3) and (7) are composed of N layers of graphene grid films separated by transparent media, wherein N is less than or equal to 6; the number of layers of the graphene grid film forming the first and second transparent absorption layers (3 and 7) is single layer, double layer or three layer; the metal grids A, B (5, 9) are both formed by two-dimensional plane structures in which grid units are periodically arranged, the period of the grid units is in the sub-millimeter to millimeter magnitude, the width of metal lines is in the sub-micron to micron magnitude, and connecting metal for communicating the two metal lines is arranged between the adjacent grid units through the overlapping of the metal lines or at the overlapping position; the distance between the metal mesh grid A (5) and the metal mesh grid B (9) is millimeter magnitude, and the distance is less than 0.25 time of the minimum shielding wavelength.

2. The double-layer metal mesh electromagnetic shielding optical window with the graphene mesh interlayer according to claim 1, wherein: arranging a single-layer or multi-layer antireflection film A (2) and a single-layer or multi-layer protective layer A (1) in parallel on the outer side part of the first transparent absorption layer (3); a single-layer or multi-layer antireflection film B (10) and a single-layer or multi-layer protective layer B (11) are sequentially arranged on the outer side part of the metal mesh B (9) in parallel.

3. The double-layer metal mesh electromagnetic shielding optical window with the graphene mesh interlayer according to claim 1, wherein: the number of layers of the graphene grid thin film which forms the first transparent absorption layer (3) and the second transparent absorption layer (7) and is separated by the transparent medium can be the same or different.

4. The double-layer metal mesh electromagnetic shielding optical window with the graphene mesh interlayer according to claim 1, wherein: the metal grids A, B (5, 9) are made of alloy materials with good conductivity, and the thickness of the alloy is larger than 100 nm.

5. The double-layer metal mesh electromagnetic shielding optical window with the graphene mesh interlayer according to claim 1, wherein: the transparent reflective layer formed from metal mesh A, B (5, 9) has a light transmission greater than 90%.

6. The double-layer metal mesh electromagnetic shielding optical window with the graphene mesh interlayer according to claim 1, wherein: the transparent medium A, B, C (4, 6, 8) and the transparent medium manufacturing material for separating the first transparent absorption layer and the second transparent absorption layer (3, 7) from the graphene grid film comprise common glass, quartz glass, infrared materials and transparent resin materials.