CN103763907B - To distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature - Google Patents

Abstract

Electromangnetic spectrum field is belonged to based on distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window of two-dimensional quadrature, the metal ring of same diameter forms net grid array by the arrangement of two-dimensional quadrature arrangement contiguity and loads on optical window transparent substrate surface, and the circumscribed connection of adjacent rings, have the sub-annulus be communicated with this annulus inscribe in each annulus, this annulus forms the elementary cell of two-dimensional metallic net grid array structure jointly as basic annulus and the sub-annulus of its inscribe; Sub-annulus junction is communicated with basic annulus with its inscribe in adjacent basic annulus junction, overlapping or the metal ensureing reliably to electrically connect between metal ring tangent point is set by lines, guarantee that all annulus are interconnected conduction.Metallic mesh structure of the present invention can reduce the inhomogeneities of net grid senior diffraction intensity distribution significantly, and the stray light that diffraction is caused distribution is more even, less to Imaging.

Description

Electromagnetic shielding window based on two-dimensional orthogonal distribution of tangent ring and inscribed sub-ring array

technical field

The invention belongs to the field of electromagnetic shielding of optical transparent parts, in particular to an electromagnetic shielding light window based on a two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays.

Background technique

With the widening and increasing intensity of the electromagnetic wave application spectrum, the requirements for electromagnetic shielding light windows used in aerospace equipment, advanced optical instruments, communication equipment, medical diagnostic instruments and security facilities are getting higher and higher, mainly requiring light windows While having a super strong broadband electromagnetic shielding ability, it also has a very high light transmittance, and the less impact on optical imaging, observation, and detection, the better. For example, the optical window of an aircraft in the field of aerospace equipment must achieve high-quality isolation of electromagnetic signals inside and outside the cabin. On the one hand, it can shield external electromagnetic interference and harmful electromagnetic signals to avoid failure of electronic equipment in the cabin. When working, the electromagnetic signal passes through the light window to cause electromagnetic leakage, but the light transmission of the light window is an essential function. The electromagnetic shielding of the light window should minimize the impact on its transparency, especially as much as possible. Does not affect optical detection or optical imaging capabilities; similarly, light windows for advanced optical instruments must have the highest possible light transmittance and the lowest possible impact on imaging quality in order to achieve high-quality detection and measurement, while preventing The influence of electromagnetic interference on the photoelectric detection device inside the instrument; for the confidential building facilities of party and government organs, military command places, and important scientific research units, it is necessary to carry out electromagnetic shielding design on the window glass of the house while ensuring lighting to prevent indoor When computers and other electronic equipment are working, important information is transmitted to the outside in the form of electromagnetic radiation to cause leakage; the light window of the electromagnetic isolation room for medical use must ensure that most of the electromagnetic waves in the room are shielded to prevent outdoor operators from being radiated by electromagnetic waves for a long time and damage their health, etc. . At present, the electromagnetic shielding of this kind of light window mainly adopts transparent conductive film, metal-induced transmission multilayer film structure, band-stop frequency selective surface and metal grid with millimeter-submillimeter period, etc.

Transparent conductive film is a kind of transparent metal oxide film with indium tin oxide as the main material. It is often used in the occasions where the visible light band is transparent, but it cannot take into account the wider light transmission band. Although it has a wider microwave shielding band, the shielding ability Not strong. The metal-induced transmission multilayer film structure uses a composite structure of multilayer thin metal film and dielectric film to realize the shielding of electromagnetic waves, and has a strong shielding ability for low-frequency microwaves. The light-transmitting area is mainly visible light and ultraviolet light, but the light transmittance is not high. . The frequency selective surface uses a periodic resonant unit structure to realize the function of a bandpass or bandstop filter. Due to its high metal coverage, it can well reflect the interference electromagnetic waves outside the working frequency band, but the optical transmittance is low, which reduces the optical efficiency. The imaging quality of detection brings difficulties to optical image processing, pattern recognition, target search and tracking. To sum up, all the above-mentioned technical solutions have obvious deficiencies in meeting the two requirements of wide-band high light transmittance and wide-band electromagnetic shielding of the light window at the same time. In contrast, the metal grid with a millimeter-submillimeter period can achieve strong low-frequency broadband electromagnetic shielding because its period is much smaller than the interference electromagnetic wavelength; and the metal grid period is much larger than the optical wavelength, which can ensure The light transmittance of the optical band. Therefore, the metal grid with a millimeter-submillimeter period has good transparent and conductive properties, which can meet the requirements of high light transmittance and broadband electromagnetic shielding for light windows, and has been widely used in the field of light window electromagnetic shielding technology:

1. Patent 03135313.5 "an observation window for electromagnetic shielding" uses a single or multiple wire mesh and a semiconductor quantum well structure to form an electromagnetic shielding structure, which can achieve a shielding efficiency of more than 50dB within 10GHz. The light transmittance reaches more than 50%.

2. Patent 93242068.0 "Electromagnetic shielding glass" sandwiches conductive metal mesh between two layers of glass, and uses conductive transparent film on the outside of the glass to bond it to the metal window frame to form an electromagnetic shielding structure. The structure has certain lighting properties.

3. Patent No. 94231862.5 "Moire-free electromagnetic shielding observation window" adopts two layers of metal mesh with different numbers placed in parallel, and their warp or weft has a certain angle to overcome the phenomenon of moiré and achieve a clearer view .

4. Patent 02157954.7 "High screen efficiency anti-information leakage glass" has a layer of polycarbonate film on both sides of the wire mesh, and a layer of glass on the outside of the film, and finally heat-pressed to form an electromagnetic shielding structure. When the rate reaches 60%, it has strong shielding efficiency.

5. Patent 200610084149.8 "Electromagnetic wave shielding film and its manufacturing method" describes a highly transparent electromagnetic shielding film with a metal mesh pattern formed by photolithography. Environmental pollution caused by the use of cured glue between layers and film substrates.

6. US Patent No. US4871220 "Short wave length pass filter having a metal mesh nasemiconducting substrate" describes a metal grid with a square structure, which is used to realize the anti-electromagnetic interference performance of the light window.

7. Patent 201010239355.8 "An electromagnetic shielding conformal optical window with latitude and longitude grid structure" describes a conformal electromagnetic shielding with a latitude and longitude metal grid structure realized by metal grid technology and conformal optical window technology The optical window mainly solves the structural design problem of the metal grid of the conformal optical window and improves the electromagnetic shielding performance of the conformal optical window.

8. Patent 200610010066.4 "Electromagnetic shielding optical window with ring metal grid structure" describes a metal grid unit with a ring shape, which is used to realize the electromagnetic shielding function of the optical window; compared with single-layer square metal grid The light transmittance and shielding ability have been improved, and the stray light caused by high order diffraction has also been homogenized to a certain extent.

9. Patent 200810063988.0 "An Electromagnetic Shielding Optical Window with a Double-layer Grid Structure" describes a grid or wire mesh with the same structural parameters placed in parallel on both sides of the optical window or transparent substrate. The electromagnetic shielding optical window formed by the side can greatly improve the electromagnetic shielding efficiency without reducing the light transmittance.

10. Patent 200810063987.6 "An Electromagnetic Shielding Optical Window with a Double-layer Ring Metal Grid Structure" describes an electromagnetic shielding optical window composed of two layers of ring metal grids loaded on both sides of the optical window to solve the problem of high transparency. The problem that light efficiency and strong electromagnetic shielding efficiency cannot be taken into account at the same time.

11. The hub-spoke structure based on the ring unit and the inductive metal mesh grid with multi-ring overlapping structure developed by JenniferI.Halman et al. of Battelle Research Institute of the United States (JenniferI.Halman et al., "Predicted and measured transmission and diffusion by ametallic mesh coating". Proc. SPIE, 2009 , 7302:73020Y-1 ~ 73020Y-8), and believed that this structure can make the high-order diffraction distribution of the grid uniform, and realize low side lobe, which is beneficial to imaging.

12. IanB.Murray from Exotic Electro-Optics, USA, Victor Densmore from the University of Arizona, VaibhavBora, etc. jointly reported that the inductive grids with hub-spoke structure and multi-ring overlapping structure introduced random distribution of parameters to the diffraction The impact of characteristics (IanB.Murray, VictorDensmore, VaibhavBora et al., "NumericalcomparisonofgridpatterndiffractioneffectthroughmeasurementandmodelingwithOptiScansoftware", Proc.SPIE, 2011, 8016: 80160U-1～80160U-15), pointed out that the spacing and diameter of each ring are randomly selected within a certain range, It is beneficial to improve the uniformity of high-order diffraction distribution.

The above schemes can achieve better electromagnetic shielding effect and a certain light transmittance due to the use of metal grids (or wire mesh) as the core shielding device. However, if a metal grid (or wire mesh) is used as the electromagnetic shielding structure, it will inevitably be affected by the diffraction of the grid in the optical band. Since the period of the metal grid is on the order of millimeters or submillimeters, in order to achieve high light transmittance, the width of its metal lines is generally on the order of microns and submicrons. Such structural parameters have a very strong diffraction effect in the optical band. Most of the energy of the incident light is transmitted by the metal grid, and the transmitted part includes zero-order diffracted light and high-order diffracted light. Usually, zero-order diffracted light is useful information for imaging and observation, and high-order diffracted light constitutes stray light. , interfere with imaging and detection. Therefore, the proportion of zero-order diffracted light should be increased as much as possible. At the same time, under the premise that high-order diffracted light is inevitable, the distribution of high-order diffracted light should be made as uniform as possible, and the stray light formed by it becomes relatively uniform. background or noise.

At present, the metal grid is mainly a traditional square grid structure, such as the structure mainly used in the above-mentioned patents 1-6 (the structure of patent 7 is a kind of grid structure because it is processed on a curved surface), and the square grid structure is transparent. There is an inherent contradiction between light ability and shielding ability, and it is difficult to take into account high light transmittance and strong electromagnetic shielding efficiency at the same time. In particular, the high-order diffraction energy of the square grid is mainly concentrated on two mutually perpendicular axes, which has a certain impact on the imaging quality. It is even difficult to apply in occasions with high image quality requirements. Changing the grid diffraction characteristics generally requires changing its structural characteristics. The above-mentioned patent 200610010066.4 "Electromagnetic shielding optical window with a ring metal grid structure" proposes to use a metal ring to form a ring metal grid, which improves the advanced quality of the square metal grid. The shortcomings of the concentrated distribution of sub-diffraction energy can alleviate the contradiction between its light transmission ability and shielding ability. In the above-mentioned documents 11 and 12, JenniferI.Halman et al. and IanB.Murray et al. also proposed a metal grid structure based on circular ring units to improve the uniformity of the high-order diffraction distribution, but the research of JenniferI.Halman et al. It is also a single-period ring arrangement structure, and the arrangement direction is determined. Its effect on adjusting high-order diffraction is equivalent to the structure proposed in patent 200610010066.4. Although the research of IanB. Murray et al. went further, they proposed a random overlapping ring structure, so that The ring diameter and spacing are randomly distributed within a certain range to further improve the uniformity of the high-order diffraction distribution, but the random distribution of the ring diameter and spacing changes the uniformity of the mesh distribution, which will damage the electromagnetic shielding efficiency.

With the increasingly complex electromagnetic environment, the requirements for the light transmission ability and electromagnetic shielding ability of the electromagnetic shielding light window are constantly increasing, especially in the field of aerospace equipment and advanced optical instruments, the light window has been required to reach 95% or even higher While having high light transmittance, it also has extremely low impact on imaging quality, and achieves a shielding efficiency of more than 30dB in the microwave frequency range below 20GHz, which makes it difficult to achieve with existing technologies. Patent 200810063988.0 and Patent 200810063987.6 both adopt double-layer metal grids placed in parallel on both sides of the transparent substrate or substrate of the light window. The two-layer metal grids have the same unit shape and structural parameters. By optimizing the two-layer grids The distance between them can greatly improve the electromagnetic shielding efficiency without reducing the light transmittance. However, the high order diffraction stray light distribution of this double-layer grid structure is still equivalent to that of a single-layer grid with the same light transmittance, which does not fully meet the requirements of future aerospace equipment and advanced optical instruments on low imaging quality.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned existing optical window electromagnetic shielding technical solutions, especially for the existence of advanced In order to solve the problem of relatively concentrated stray light distribution caused by sub-diffraction, an electromagnetic shielding light window based on two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays was developed to achieve depth homogenization and extremely low Imaging quality affects the purpose.

The purpose of the present invention is achieved like this: adopt a kind of electromagnetic shielding light window based on two-dimensional orthogonal distribution tangent ring and inscribed sub-ring array, the metal grid in the electromagnetic shielding light window is made of metal rings of the same diameter. The basic rings are arranged in close contact with two-dimensional orthogonal distribution and loaded on the surface of the transparent substrate of the light window, and the adjacent basic rings are circumscribed and connected; each basic ring is provided with its inscribed connection, metal The sub-rings, the basic ring and its inscribed sub-rings together form the basic unit of the two-dimensional grid array structure; the diameter of the basic ring and its inscribed sub-rings is millimeters and sub-rings On the order of millimeters, the metal line width of the sub-ring connected between the basic ring and its inscribed ring is on the order of micron and submicron; the described circumscribed connection includes: ① the two rings are circumscribed and the circumscribed points are set The connecting metal that connects the two rings, ②The lines at the joint of the two rings are in a seamless overlapping structure, ③The lines at the joint of the two rings are in a seamless overlapping structure, and at the same time, the two rings are set at the overlap Connected connecting metal; the inscribed connection includes: ① two rings are inscribed and a connecting metal connecting the two rings is set at the inscribed tangent point; ② two rings have a seamless overlapping structure at the joint; ③ While the lines at the joint of the two rings are in a seamless overlapping structure, a connecting metal connecting the two rings is provided at the overlap.

In the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, the number of sub-rings in each basic unit is greater than or equal to 2, and the diameters are the same or different, and the adjacent sub-rings The included angle formed by the center of the ring and the line connecting the centers of the basic rings is any angle, and the sub-rings in different basic units are rings of equal diameter or non-equal diameter, and the numbers are the same or different.

The above-mentioned electromagnetic shielding light window is based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, and the adjacent sub-rings in the basic unit can be circumscribed or intersected.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, the diameters of the sub-rings in the basic unit are the same, and the diameters of adjacent sub-rings The included angle formed by the line connecting the center of the circle and the center of the basic ring is equal.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays has the same number of sub-rings in different basic units and the same diameter.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, the relative positions of the sub-rings in the different basic units are the same, and a basic After the cells are copied, they are arranged in close contact with each other according to two-dimensional orthogonal distribution to form a two-dimensional grid array.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, in the two-dimensional grid array, the sub-rings in adjacent basic units The relative positions are different, and a two-dimensional grid array is formed by copying a basic unit and arranged closely in two-dimensional orthogonal distribution, in which any basic unit circles its own basic circle in a two-dimensional plane relative to its adjacent basic units The center of the circle is rotated by a certain angle.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, any basic unit in the same row rotates at the same angle relative to the adjacent basic unit .

The above-mentioned electromagnetic shielding light window based on two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, the basic rings and sub-rings are both made of alloy with good electrical conductivity, and the thickness of the alloy is greater than 100nm.

In the electromagnetic shielding light window based on two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, the bonding layer is made of chromium or titanium.

The innovation and good effect of the present invention are:

The metal grid in the electromagnetic shielding light window is composed of metal rings of the same diameter as the basic rings arranged in a two-dimensional orthogonal distribution and arranged in close contact, and loaded on the surface of the transparent substrate of the light window, and the adjacent basic rings are circumscribed and connected. The innovation of the present invention lies in that: each basic ring is provided with a metal sub-ring that is inscribed and communicated with it, and the described basic ring and its inscribed and connected sub-rings together form a two-dimensional grid array structure The basic unit; the diameter of the basic ring and its inscribed sub-rings is on the order of millimeters and submillimeters, and the metal line width of the basic ring and its inscribed sub-rings is microns and sub-millimeters micron level; the circumscribed connection includes: ① the two rings are circumscribed and the connecting metal connecting the two rings is arranged at the circumtangent point; ② the lines at the joint of the two rings are in a seamless overlapping structure; While the lines at the joints of the rings are in a seamless overlapping structure, a connecting metal connecting the two rings is arranged at the overlap; the inscribed connection includes: ① the two rings are inscribed and the inscribed point is set with a The connecting metal of the two rings, ②The lines at the joint of the two rings are in a seamless overlapping structure, ③The lines at the joint of the two rings are in a seamless overlapping structure, and at the same time, the two rings are connected at the overlap connection metal. The good effect produced by the innovation of the present invention mainly focuses on the high-order diffraction energy distribution of the homogenized metal grid, as follows:

The basic rings in the metal grid adopt two-dimensional orthogonal distribution as the basic arrangement, which overcomes the shortcomings of the concentrated distribution of high-order diffraction energy in the traditional grid metal grid, and has a good homogenized high-order diffraction energy distribution. This is one of the reasons for the homogeneous high-order diffraction energy distribution of the metal grid of the present invention.

The sub-ring array in the metal mesh grid, because of the difference in the number, diameter and positional relationship of the sub-rings in each basic unit, makes its structure loose and stray, so the high-order diffraction energy is low, and The higher-order diffraction distribution is relatively uniform, avoiding the concentrated distribution of higher-order diffraction energy that exists in traditional square metal grids. This is the second reason for the metal grid of the present invention to homogenize the distribution of higher-order diffraction energy.

Adding sub-rings to the basic ring to form the basic unit, while ensuring the same light transmittance, compared with the structure with only the basic ring array, it is necessary to increase the diameter of the basic ring, which reduces the advanced level of each array as a whole. Second diffraction energy; and because the superposition probability of the high order diffraction produced by the sub-annular array structure and the high order diffraction of the basic annular array structure is very low, especially after optimizing the structure and parameters, their higher energy high order diffraction does not occur Superposition, thereby homogenizing the distribution of high-order diffraction energy, which is the third reason why the metal grid of the present invention homogenizes the distribution of high-order diffraction energy.

Each basic unit can be rotated at a certain angle around the center of its basic ring without changing the aperture ratio of the metal grid and thus not affecting the light transmittance, but the energy distribution of the higher-order diffraction orders can be further modulated to achieve better This is the fourth reason why the metal grid of the present invention homogenizes the energy distribution of high-order diffraction.

To sum up, the metal grid structure of the present invention can realize the depth homogenization of the high-order diffraction energy distribution of the grid, which is the most prominent effect of the present invention. In addition, adding sub-rings to the basic ring structure effectively improves the uniformity of the metal ring grid structure, and when the basic unit rotates at a certain angle around the center of the basic ring, it will not change the metal grid structure. The uniformity of the structure basically does not affect the electromagnetic shielding effect while effectively modulating the energy distribution of the high-order diffraction order, and even improves the electromagnetic shielding effect in some preferred solutions.

Description of drawings

Fig. 1 is a schematic cross-sectional view of a preferred structure of an electromagnetic shielding light window based on a two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays.

Fig. 2 is a schematic diagram of the basic ring distribution of the electromagnetic shielding light window based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays.

Fig. 3 is a schematic diagram of basic units respectively containing 2, 3, 4, and 5 circumconnecting sub-rings of the same diameter.

Fig. 4 is a schematic diagram of basic units respectively containing 3, 4, 5, and 6 intersecting linker rings of the same diameter.

Fig. 5 is a schematic diagram of a basic unit composed of sub-rings with different diameters.

Fig. 6 is a schematic diagram of the circumscribed connection mode of two circular rings.

Fig. 7 is a schematic diagram of the inscribed connection mode of two circular rings.

Fig. 8 is a schematic diagram of a rotation mode of a basic unit of the present invention relative to an adjacent basic unit.

Fig. 9 is a schematic diagram of an existing square grid structure.

Fig. 10 is a schematic diagram of the existing square grid high-order diffraction and its relative intensity distribution.

Fig. 11 is a schematic diagram of the existing ring grid structure.

Fig. 12 is a schematic diagram of the high-order diffraction of the existing annular grid and its relative intensity distribution.

Fig. 13 is a schematic diagram of the metal grid structure of preferred solution A in the present invention.

Fig. 14 is a schematic diagram of the high-order diffraction of the metal grid and its relative intensity distribution of the preferred solution A in the present invention.

Fig. 15 is a schematic diagram of the metal grid structure of the preferred solution B in the present invention.

Fig. 16 is a schematic diagram of the high-order diffraction of the metal grid and its relative intensity distribution of the preferred solution B in the present invention.

Fig. 17 is a comparative diagram of the maximum relative intensity of high-order diffraction of four kinds of grid structures.

Part number description in the picture: 1. Adhesive layer 2. Protective layer 3. Anti-reflection film 4. Transparent substrate 5. Metal grid 6. Basic ring 7. Sub-ring 8. Connecting metal

Detailed ways

The present invention is further described below with reference to accompanying drawing and preferred embodiment:

Based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays, the electromagnetic shielding light window is characterized in that: the metal grid 5 in the electromagnetic shielding light window consists of a metal ring of the same diameter as the basic ring 6 according to the two-dimensional Orthogonal distribution and close arrangement are formed and loaded on the surface of the transparent substrate of the light window, and the adjacent basic rings 6 are circumscribed and connected; each basic ring 6 is provided with a metal sub-ring 7 that is inscribed and communicated with it. , the basic ring 6 and its inscribed sub-ring 7 together form the basic unit of the two-dimensional grid array structure; the diameter of the basic ring 6 and its inscribed sub-ring 7 are mm and The sub-millimeter level, the metal line width of the sub-ring 7 connected with the basic ring 6 and its inscribed part is micron and sub-micron level; the described circumscribed connection includes: The connection metal 8 connecting the two rings is set at the point, ② the lines of the two rings are in a seamless overlapping structure, and ③ the lines of the two rings are in a seamless overlapping structure, and the overlapping structure is set The connection metal 8 connecting the two rings; the inscribed communication includes: 1. the two rings are inscribed and the connecting metal 8 connecting the two rings is set at the inscribed tangent point; Seam overlapping structure, ③ the lines of the two rings are in a seamless overlapping structure at the joint, and a connecting metal 8 connecting the two rings is arranged at the overlap. The transparent substrate 4 can be any transparent material, as long as it can be used as a transparent light window material that meets the requirements of the application, and the metal grid 5 can be processed on it according to a certain process flow; according to the process flow, the metal grid 5 can be Loaded on the surface of the transparent substrate 4 through the adhesive layer 1; the single-layer or multi-layer antireflection film 3 enhances the light transmission ability of the light window, and the single-layer or multi-layer protective layer 2 is used to prevent the metal part from being exposed to the air for a long time Corrosion and oxidation are caused, the shielding ability is reduced, and the metal grid 5 is prevented from being scratched.

The electromagnetic shielding light window based on the two-dimensional orthogonal distribution tangent ring and the inscribed sub-ring array of the present invention uses metal rings of the same diameter as the basic rings 6 to be closely arranged in two-dimensional orthogonal distribution to form a grid array And loaded on the surface of the transparent substrate of the light window, and the adjacent basic rings 6 are circumscribed and connected. The distribution of the basic rings 6 is shown in Figure 2. Points A, B, C, and D in Figure 2 are four adjacent basic The center of the ring 6, any one of the four adjacent basic rings is adjacent to the other two rings and connected circumscribedly, a square can be formed with the center of the circle ABCD as the vertex, and any other four are as follows The centers of the basic rings 6 arranged adjacently form a square as the apex, that is, the centers of all the basic rings 6 form a two-dimensional orthogonal equidistant lattice. Such an arrangement ensures that all the basic rings 6 are The metal mesh grid 5 is formed by a two-dimensional orthogonal distribution and a close-connected arrangement.

The present invention is based on two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring array electromagnetic shielding light windows, each basic ring 6 has a sub-ring 7 inscribed with the ring, and the basic ring 6 and its The inscribed connected sub-rings 7 together form the basic unit of the two-dimensional grid array structure. The diameter of the basic ring 6 and the sub-ring 7 is on the order of millimeters and submillimeters, and the width of the metal lines of the basic ring 6 and the sub-rings 7 is on the order of microns and sub-microns, so as to ensure high light transmittance and good electromagnetic shielding effect . In addition, each ring part is made of a metal with good electrical conductivity, such as gold, silver, copper, aluminum and other pure metals and metal alloys, and the thickness of the metal is greater than 100 nm.

In the electromagnetic shielding light window based on two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays of the present invention, the number of sub-rings 7 in each basic unit is greater than or equal to 2, and the diameters are the same or different. The angle formed by the center of the ring 7 and the line connecting the centers of the basic ring 6 is any angle; the adjacent sub-rings 7 in the basic unit are tangentially connected or intersected. As shown in Fig. 3 and Fig. 4, the preferred scheme is that the diameter of the sub-annular 7 in the basic unit is the same, and the angle formed by the center of the adjacent sub-annular 7 and the line connecting the centers of the basic annulus 6 is equal: Fig. 3 is the basic The sub-rings 7 of the same diameter in the unit are circumscribed and connected, and Fig. 3 (a) (b) (c) (d) respectively represent the schematic diagrams of the basic units of the 7 sub-rings whose numbers are 2, 3, 4, and 5; 4 is the intersecting connection of the sub-rings 7 of the same diameter in the basic unit, where Figure 4 (a) (b) (c) (d) respectively represent the schematic diagrams of the basic units with 7 sub-rings numbered 3, 4, 5, and 6 . Figure 5 lists a schematic diagram of a basic unit composed of three sub-rings 7 with different diameters, wherein R1, R2, and R3 are the radii of the sub-rings 7, and R1≠R2≠R3, the centers of adjacent sub-rings 7 and the basic The included angles formed by the lines connecting the centers of the rings 6 are different.

Fig. 6 and Fig. 7 respectively represent the circumscribed communication and inscribed communication of each two circular rings, and the metals that ensure the reliable electrical connection between the tangent points of the metal rings are ensured by lines overlapping or setting (such as covering), so as to ensure that the tangent metal rings are connected to each other. Closely connected to conduct electricity. Among them, Figure 6(a)(b)(c) respectively show the schematic diagrams of the seamless overlapping structure of the two rings when they are circumscribed connected: Figure 6(a) shows the general situation of the seamless overlapping of the two rings, that is, the two circles The center-to-center distance of the rings is less than the distance between the two rings when they are circumscribed, and is greater than the difference between the center-to-center distance when the two rings are circumscribed and the sum of the line widths of the two rings. Figure 6(b) is a seamless overlapping In a special case, the inner and outer contours of the two rings circumscribe each other. Figure 6(c) is another special case of seamless overlap. The center distance of the two rings is equal to the distance between the centers of the two rings and the The difference between the sum of the widths of the ring lines, that is, the inner contours of the two ring lines is circumscribed, and in Figure 6(d) because the two rings are circumscribed, it is necessary to set a reliable electric current between the tangent points of the metal rings at the point of tangency. Jointed metal. Figure 7(a) and (b) respectively show the schematic diagrams of the seamless overlapping structure of two rings when inscribed connected: Figure 7(a) shows the general situation of seamless overlapping of two rings when inscribed connected, that is, two The center-to-center distance of the ring is greater than the distance between the two rings when they are inscribed, and is less than or equal to the sum of the center-to-center distance when the two rings are inscribed and the line width of the larger-diameter ring. Figure 7(b) shows that the inscribed connection A special case where two rings overlap seamlessly, the distance between the centers of the two rings is equal to the sum of the distance between the centers of the two rings when they are inscribed and the line width of the ring with a larger diameter, that is, the inner contour of the lines of the two rings Fig. 7(c) shows that the outer contour of the ring line with a smaller diameter is inscribed with the inner contour of the ring line with a larger diameter. . In addition, if the overlapping area of the two metal rings is small when the two rings overlap seamlessly, it is not enough to ensure a reliable electrical connection between the two metal rings, and it is also necessary to set a guaranteed metal ring tangent point at the tangent point. Metals that can be electrically connected between metal rings to ensure the circumscribed or inscribed communication of the metal rings. Figure 6(d) and Figure 7(c) show a preferred metal connection method at the tangent point, the connecting metal 8 covered at the tangent point is a rectangle, the side length of the rectangle is greater than the line width of the metal ring, and the rectangle covers the cut When pointing the connection, one side of the rectangle should completely fall within a metal ring line, and its opposite side should completely fall within another tangent metal ring line. According to different processing methods and technological levels, other forms of connecting metals can also be used at the tangent point of the rings, as long as the two tangent metal rings can have reliable electrical connection.

In the present invention, the sub-rings 7 in different basic units are equal-diameter or non-equal-diameter rings, and the numbers are the same or different, so as to achieve the purpose of homogenizing the stray light caused by high-order diffraction. As a preferred solution, the diameters of the sub-rings 7 in the basic unit are the same, and the angles formed by the centers of the adjacent sub-rings 7 and the lines connecting the centers of the basic rings 6 are equal; The 7 sub-rings have the same number and equal diameters. As a special example of this preferred solution, the relative positions of the sub-rings 7 in different basic units are the same, and the metal mesh grid 5 is formed by a two-dimensional orthogonal distribution after duplication of a basic unit. In order to achieve a good homogenization of the stray light effect caused by high-order diffraction, as another special case of this preferred solution, the relative positions of the sub-rings 7 in adjacent basic units in the metal grid 5 array in the present invention are different, and A basic unit is copied and arranged closely in two-dimensional orthogonal distribution to form a two-dimensional grid array, in which any basic unit is rotated at a certain angle around the center of its own basic ring 6 in a two-dimensional plane relative to its adjacent basic units , the rotation angles of any basic unit in the same row relative to adjacent basic units can be the same; for example, Fig. 8 is a schematic diagram of a rotation mode of a basic unit of the present invention relative to adjacent basic units, wherein the basic unit selection diagram of the metal grid 5 In the structure of 4(b), each basic unit in the same row is rotated by 60° relative to the adjacent basic units.

Fig. 9 and Fig. 10 are the schematic diagrams of the existing square grid structure and its high-order diffraction and its relative intensity distribution in US Patent No. 4871220 respectively. Fig. 11 and Fig. 12 are the schematic diagrams of the existing ring grid structure and Its schematic diagram of high order diffraction and its relative intensity distribution; Fig. 13 and Fig. 14 are respectively the schematic diagram of the metal grid structure of the preferred scheme A in the present invention and its high order diffraction and its relative intensity distribution diagram, the metal grid in the preferred scheme A The structure of Fig. 3 (c) is selected as the basic unit and there is no relative rotation between the basic units; Fig. 15 and Fig. 16 are the schematic diagram of the metal grid structure of the preferred scheme B in the present invention and its high-order diffraction and its relative intensity distribution Schematic diagram, the metal grid of the preferred scheme B still uses the structure of Figure 3(c) as the basic unit, but different from the preferred scheme A, the adjacent basic units of the preferred scheme B are rotated according to the rotation method shown in Figure 8 , and the rotation angle is 22.5°.

In order to illustrate the superiority of the present invention in the homogenization of the high-order diffraction energy distribution, based on the scalar diffraction theory, the theoretical calculations are carried out on the high-order diffraction energy distribution of the above four structures and the maximum relative intensity of the high-order diffraction. During the calculation, each The light transmittance of the structure is the same (both are 95.4%), and their zero-order relative intensities are both 91%, that is, the proportion of useful information for imaging is the same. Fig. 10, Fig. 12, Fig. 14 and Fig. 16 respectively provide the homogenization degree of high-order diffraction of four kinds of structures, show that: the metal grid structure in preferred scheme A and B is compared with square grid, ring grid, The relative intensity of the highest-order diffraction is significantly reduced, and the number of high-order diffraction spots is significantly increased in the same investigation interval, thus avoiding the problem that the high-order diffraction energy is concentrated on a few diffraction orders, and making the high-order diffraction energy distribution more uniform ; Fig. 17 is the concrete numerical value of the maximum relative intensity of the higher order diffraction of above-mentioned four kinds of structures, it can be seen that the maximum relative intensity of the higher order diffraction of the lattice metal grid structure is obviously higher than other structures, and the preferred scheme A of the present invention corresponds The maximum relative intensity of high-order diffraction of the metal grid structure has been significantly reduced, from 0.0259% (the maximum relative intensity of high-order diffraction of the existing circular ring grid structure) to 0.0168%, which is reduced by 35%. The homogenization effect is obvious; the maximum relative intensity of the higher-order diffraction of the metal grid structure of the preferred scheme B is further reduced, and drops to 0.0058% from 0.0259% (the maximum relative intensity of the higher-order diffraction of the existing circular ring grid structure), which reduces the 78%, completed the depth averaging of high-order diffraction. In summary, the metal grid structure of the present invention has a very significant effect on homogenizing the distribution of high-order diffraction energy, which is not only superior to the existing grid metal grid structure in US Patent No. Ring metal grid structure.

The composition of the basic ring 6 and the sub-ring 7 of the present invention makes the mesh relatively average, and while the depth averages the high-order diffraction energy distribution, it still has good light transmission and shielding performance. When used to construct a double When the single-layer metal grid structure is used, the contradictory problem of light transmittance and shielding efficiency can be improved. At the same time, because the single-layer structure of the present invention is deeply homogenized and the distribution of high-order diffraction energy can be solved, it can also solve the problem in the existing double-layer metal grid structure. Due to the limitation of the single-layer grid structure, it is impossible to further homogenize the distribution of high-order diffraction energy.

The metal mesh grid 5 in the electromagnetic shielding light window based on the two-dimensional orthogonal distribution of the tangent ring and the inscribed sub-ring array of the present invention can be processed by the following processing method: a mask is made by electron beam direct writing, etc. The window transparent substrate 4 is cleaned and then plated with chrome or titanium as the adhesive layer 1, coated with a metal film, then coated with photoresist, photolithography is carried out using the processed mask, and finally dry or wet etching is carried out , to get the grid pattern after removing the glue. It is also possible to omit the process of making the mask, and directly use the method of laser direct writing to make the metal grid pattern based on the two-dimensional orthogonal distribution of tangent rings and inscribed sub-ring arrays. Other microelectronic processing processes or binary optical element manufacturing processes can also be used to manufacture the metal grid structure of the present invention.

The transparent substrate 4 involved in the present invention is determined by the actual application, and can be ordinary glass, quartz glass, infrared material, transparent resin material and the like. The metal structure of the basic ring 6 and the sub-ring 7 of the present invention should be based on the transparent substrate 4 to take a suitable processing process to make it completely covered on the transparent substrate 4, and can realize reliable electrical connection or connection with the window frame or the like. Sealed to ensure excellent electromagnetic shielding function. In practical applications, the transparent substrate 4 with the grid structure of the present invention can be coated with an anti-reflection film to increase the light transmission capacity, and can also be coated with a protective layer on the surface of the grid layer to prevent the metal structure from being corroded or placed in the air for a long time. Oxidation reduces the shielding ability and also prevents the grid layer from being scratched, worn or otherwise damaged.

Claims (7)

1. to distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature, metallic mesh (5) in electromagnetic shielding optical window is formed and loads on optical window transparent substrate surface as basic annulus (6) by two-dimensional quadrature contiguity arrangement arranged evenly by the metal ring of same diameter, and adjacent basic annulus (6) circumscribed connection; It is characterized in that: be provided with in each basic annulus (6) be communicated with its inscribe, the sub-annulus (7) of metal, the sub-annulus (7) that described basic annulus (6) is communicated with its inscribe forms the elementary cell of two-dimensional mesh grid array structure jointly; The diameter of the sub-annulus (7) that described basic annulus (6) is communicated with its inscribe is millimeter and submillimeter magnitude, and the metal wire width of the sub-annulus (7) that described basic annulus (6) is communicated with its inscribe is micron and sub-micrometer scale; In described each elementary cell, the number of sub-annulus (7) is more than or equal to 2, and diameter is identical or different, the angle that the center of circle of adjacent sub-annulus (7) and basic annulus (6) circle center line connecting form is arbitrarily angled, sub-annulus (7) in different elementary cell is equal diameter or non-equal diameter annulus, and number is identical or different; The tangent connection of adjacent sub-annulus (7) or crossing in elementary cell; Described circumscribed connection comprises: 1. circumscribed the and circumscribed point of contact place of two annulus arranges the connection metal (8) be communicated with by two annulus, 2. two annulus are seamless overlapping configuration at junction lines, 3. two annulus are while junction lines are seamless overlapping configuration, arrange the connection metal (8) be communicated with by two annulus at overlapping place; Described inscribe is communicated with and comprises: 1. two annulus inscribes and inscribe point of contact place arranges the connection metal (8) be communicated with by two annulus, 2. two annulus are seamless overlapping configuration at junction lines, 3. two annulus are while junction lines are seamless overlapping configuration, arrange the connection metal (8) be communicated with by two annulus at overlapping place.

2. according to claim 1ly to distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature, it is characterized in that: the diameter of elementary cell neutron annulus (7) is identical, the angle that the center of circle of adjacent sub-annulus (7) and basic annulus (6) circle center line connecting form is equal.

3. according to claim 2ly to distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature, it is characterized in that: sub-annulus (7) number in different elementary cell is identical, equal diameters.

4. according to claim 3ly to distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature, it is characterized in that: sub-annulus (7) relative position in different elementary cell is identical, and form two-dimensional mesh grid array by two-dimensional quadrature contiguity arrangement arranged evenly after an elementary cell copies.

5. according to claim 3ly to distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature, it is characterized in that: in two-dimensional mesh grid array, sub-annulus (7) relative position in neighboring unit cells is different, and two-dimensional mesh grid array is formed by two-dimensional quadrature contiguity arrangement arranged evenly after an elementary cell copies, wherein any one elementary cell rotates to an angle around self basic annulus (6) center of circle in two dimensional surface relative to its neighboring unit cells.

6. according to claim 5ly to distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature, it is characterized in that: the angle rotated relative to neighboring unit cells with any elementary cell in a line is identical.

7. according to claim 1ly to distribute tangent annulus and inscribe sub-circle ring array electromagnetic shielding optical window based on two-dimensional quadrature, it is characterized in that: basic annulus (6) is formed by the alloy that electric conductivity is good with sub-annulus (7), and alloy thickness is greater than 100nm.