CN103813700B - Based on the electromagnetic shielding optical window of multicycle metal ring two-dimensional quadrature nested array - Google Patents

Abstract

The electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings belongs to the field of electromagnetic shielding technology. Two sets of concentric ring pairs are respectively arranged in two-dimensional orthogonal arrangement to form a two-dimensional metal grid and overlapped. Loaded on the surface of the transparent substrate of the light window; a group of concentric rings paired with the middle and outer rings as the basic ring, which contains inscribed connected sub-rings inside, and the two together form the basic unit of the two-dimensional grid structure and form a basic ring array ; Another set of concentric ring pairs constitutes a modulated ring array; the basic ring array and the modulated ring array are overlapped and distributed to form a two-dimensional orthogonal nested array structure. At the joints where the rings are tangent to each other, overlap the lines or set metal to ensure reliable electrical connection between the tangent points of the metal rings, so as to ensure that all the rings conduct electricity with each other. The metal grid structure of the invention can significantly reduce the inhomogeneity of the high-order diffraction light intensity distribution of the grid, make the distribution of stray light caused by diffraction more uniform, and have less impact on imaging.

Description

Electromagnetic shielding light window based on two-dimensional orthogonal nested array of multi-period metal rings

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 nested array of multi-period metal rings.

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 "Moiré-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 fringes 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 US4871220 "Short wavelength pass filter having a metal mesh on asemiconducting 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 grid with multi-ring overlapping structure developed by Jennifer I.Halman et al. a metallic mesh coating". Proc. SPIE, 2009, 7302: 73020Y-1～73020Y-8), and it is believed that this structure can homogenize the high-order diffraction distribution of the grid and achieve low side lobes, which is beneficial to imaging.

12. Ian B. Murray from Exotic Electro-Optics, USA, Victor Densmore from the University of Arizona, Vaibhav Bora, and others jointly reported the introduction of parameter random distribution design to the inductive grid of hub-spoke structure and multi-ring overlapping structure The impact on the diffraction characteristics (Ian B. Murray, Victor Densmore, Vaibhav Bora et al., "Numerical comparison of grid pattern diffraction effects through measurement and modeling with OptiScan software", Proc.SPIE, 2011, 8016: 80160U-1-80160U 15), it is pointed out that the distance and diameter of each ring are randomly selected within a certain range, which is conducive to improving the uniformity of the 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, Jennifer I.Halman et al. and Ian B.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 Jennifer I.Halman et al. Human research 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 Ian B. Murray et al. went further, they proposed random overlapping circles The ring structure makes the diameter and spacing of the rings randomly distributed within a certain range to further improve the uniformity of the high-order diffraction distribution, but the random distribution of the diameter and spacing of the rings 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 To solve the problem of relatively concentrated stray light distribution caused by sub-diffraction, an electromagnetic shielding light window based on a two-dimensional orthogonal nested array of multi-period metal rings was developed to achieve depth homogenization of high-order diffraction and extremely low impact on imaging quality the goal of.

The technical scheme adopted in the present invention is: an electromagnetic shielding light window based on a two-dimensional orthogonal nested array of multi-period metal rings, the metal grid in the electromagnetic shielding light window is composed of two groups of concentric metal ring pairs respectively according to two-dimensional orthogonal Distributed arrangement closely arranged and overlapped and loaded on the surface of the transparent substrate of the light window; the outer ring of a group of concentric metal ring pairs as the basic ring contains sub-rings connected with its inscribed metal, concentric rings The sub-rings that are connected inscribed together form the basic unit of the two-dimensional metal grid structure and form a basic ring array. In the basic ring array, the diameters of each basic ring are equal and the adjacent basic rings are connected externally; Each ring pair in a group of concentric metal ring pairs is used as a modulation unit to form a modulation ring array, and the outer rings of each modulation unit are used as a modulation basic ring. The array and the modulation ring array form an overlapping distribution structure. The diameters of the rings in the basic unit and the modulation unit are on the order of millimeters and submillimeters, and the widths of the metal lines of the rings in the basic unit and the modulation unit are on the order of microns and submicrons; the circumscribed connection includes: ① two The ring is circumscribed and the connecting metal connecting the two rings is set at the circumscribed tangent point. ②The lines of the two rings are in a seamless overlapping structure. ③The lines of the two rings are in a seamless overlapping structure. , the connecting metal connecting the two rings is arranged at the overlap; the inscribed connection includes: ① the two rings are inscribed and the connecting metal connecting the two rings is set at the inscribed tangent point, and ② the two rings are connected The lines at the joint are in a seamless overlapping structure, ③ the lines at the joint of the two rings are in a seamless overlapping structure, and a connecting metal connecting the two rings is set at the overlapping position.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings, the diameter of the sub-rings in the basic unit is the same, and the diameter of the sub-ring is the same as that of the basic unit. The inner rings of the ring pair are circumscribed and connected; the angles formed by the centers of the adjacent sub-rings and the lines connecting the centers of the basic rings are equal; the number of sub-rings in the adjacent basic units is the same, and the diameters are equal.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings, the diameter of the outer rings of the basic unit and the two groups of concentric ring pairs in the modulation unit is equal , the diameter of the inner ring is equal, and the basic ring array and the modulation ring array are arranged overlappingly, the inner ring of each modulation unit is connected with the four basic rings circumscribed, and the inner ring of each basic unit is connected with The four modulation basic rings are circumscribed and connected to form a two-dimensional orthogonal nested ring array.

As a preferred structure, the above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings, each of the basic units contains four sub-rings, and each sub-ring is connected to A basic torus is inscribed connected, and a modulation basic torus is inscribed connected.

The above-mentioned electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings, the two groups of concentric ring pairs, the sub-rings and the connecting metal are all made of alloys with good electrical conductivity, and the thickness of the alloy is greater than 100nm.

In the electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings, the bonding layer is made of chromium or titanium.

The innovation and good effect of the present invention are:

The innovation of the present invention lies in that the metal grid in the electromagnetic shielding light window is composed of two groups of concentric metal ring pairs arranged in a two-dimensional orthogonal distribution and arranged in close contact, and are loaded on the surface of the transparent substrate of the light window in an overlapping distribution; The outer ring of a group of concentric metal ring pairs is used as a basic ring, and its interior contains metal sub-rings that are inscribed and connected with it. The basic unit constitutes a basic ring array. In the basic ring array, the diameters of each basic ring are equal and the adjacent basic rings are circumscribed and connected; each ring pair in another group of concentric metal ring pairs is used as a modulation unit to form a modulation circle. In the ring array, the outer ring of each modulation unit is used as the modulation basic ring with the same diameter and the adjacent modulation rings are circumscribed and connected; the basic ring array and the modulation ring array form an overlapping distribution structure. The diameters of the rings in the basic unit and the modulation unit are on the order of millimeters and submillimeters, and the widths of the metal lines of the rings in the basic unit and the modulation unit are on the order of microns and submicrons; the circumscribed connection includes: ① two The ring is circumscribed and the connecting metal connecting the two rings is set at the circumscribed tangent point. ②The lines of the two rings are in a seamless overlapping structure. ③The lines of the two rings are in a seamless overlapping structure. , the connecting metal connecting the two rings is arranged at the overlap; the inscribed connection includes: ① the two rings are inscribed and the connecting metal connecting the two rings is set at the inscribed tangent point, and ② the two rings are connected The lines at the joint are in a seamless overlapping structure, ③ the lines at the joint of the two rings are in a seamless overlapping structure, and a connecting metal connecting the two rings is set at the overlapping position. 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 two sets of concentric ring pairs in the metal grid are basically arranged in two-dimensional orthogonal distribution, which can overcome the shortcomings of the concentrated distribution of high-order diffraction energy existing in traditional square metal grids, and have good homogenized high-order diffraction The characteristics of energy distribution, and the use of two sets of concentric ring pairs overlapping two-dimensional metal ring arrays in two-dimensional orthogonal distribution, while ensuring the same light transmittance, compared with the structure of only a single-diameter ring array, it is necessary to increase each The diameter of the rings and the higher-order diffraction energy of each ring array are reduced; at the same time, the structure is optimized by changing the diameter of each ring or the positional relationship of two groups of concentric rings, so that their higher-order diffraction orders do not occur Superposition, so that the high-order diffraction energy distribution of the metal grid array structure can be effectively adjusted to achieve the purpose of homogenizing the high-order diffraction energy distribution, which is one of the reasons for the metal grid of the present invention to homogenize the high-order diffraction energy distribution.

The basic unit is formed by adding sub-rings to the pair of concentric rings, because the number, diameter and positional relationship of the sub-rings in each basic unit are different, making the structure loose and stray arrangement, so the high-order diffraction energy It is relatively low, and the high-order diffraction distribution is relatively uniform, avoiding the concentrated distribution of high-order diffraction energy that exists in traditional square metal grids; at the same time, to ensure the same light transmittance, it is necessary to further increase two pairs of concentric rings. The diameter of the diameter reduces the high-order diffraction energy of each array as a whole; and because the high-order diffraction generated by the sub-annular array structure and the high-order diffraction of the two concentric ring array structures have a very low probability of superposition; especially changing The positional relationship of the two concentric ring pairs and the diameter of each ring interact with different sub-ring structures. After further optimization of the parameters, their higher-order diffractions with higher energy do not overlap, thus averaging the higher-order diffraction energy This is the second reason for the metal grid of the present invention to homogenize the energy distribution of high-order diffraction.

By changing the number of sub-rings in the basic unit or the diameter ratio of the sub-rings and the inner ring in the basic unit, the energy distribution of the high-order diffraction order can be homogenized, which is the metal mesh grid of the present invention. The third reason for energy distribution.

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, the two groups of concentric rings work together to effectively improve the uniformity of the metal ring grid structure, and effectively improve the energy distribution of high-order diffraction orders. At the same time of modulation, the electromagnetic shielding effect is basically not affected, and even the electromagnetic shielding effect can be improved 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 nested array of multi-period metal rings.

Fig. 2 is a schematic diagram of the basic structure of a typical two-dimensional grid composed of two groups of concentric circular ring pairs overlapping two-dimensional orthogonal arrangement.

Fig. 3 is a schematic diagram of several basic units when the sub-ring circumscribes the inner ring of the pair of concentric rings.

Fig. 4 is a schematic diagram of the circumscribed connection mode of two circular rings.

Fig. 5 is a schematic diagram of the inscribed connection mode of two circular rings.

Fig. 6 is a schematic diagram of an existing square grid structure.

Fig. 7 is a schematic diagram of the existing square grid high-order diffraction and its relative intensity distribution.

Fig. 8 is a schematic diagram of the existing ring grid structure.

Fig. 9 is a schematic diagram of high-order diffraction and its relative intensity distribution of an existing annular grid.

Fig. 10 is a schematic diagram of the metal grid structure of the preferred solution A in the present invention.

Fig. 11 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. 12 is a comparative diagram of the maximum relative intensity of high-order diffraction of three 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. Modulation basic ring 9. Connecting metal

Detailed ways

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

The electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings is characterized in that: the metal grid 5 in the electromagnetic shielding light window is composed of two groups of concentric metal ring pairs respectively arranged in two-dimensional orthogonal distribution and closely connected It is arranged and loaded on the surface of the transparent substrate of the light window by overlapping distribution; the outer ring of a group of concentric metal ring pairs is used as the basic ring 6, and its interior contains a metal sub-ring 7 that is inscribed and communicated with it. The ring pair and its inscribed sub-rings 7 together form the basic unit of the two-dimensional metal grid structure and form a basic ring array. In the basic ring array, each basic ring 6 has the same diameter and the adjacent basic ring 6 In another group of concentric metal ring pairs, each ring pair is used as a modulation unit to form a modulation ring array, and the outer ring of each modulation unit is used as a modulation basic ring 8. The outer diameter of the modulation basic ring 8 is equal and adjacent. connected; the basic ring array and the modulated ring array form an overlapping distribution structure. The diameters of the rings in the basic unit and the modulation unit are on the order of millimeters and submillimeters, and the widths of the metal lines of the rings in the basic unit and the modulation unit are on the order of microns and submicrons; the circumscribed connection includes: ① two The ring is circumscribed and the connecting metal 9 connecting the two rings is set at the circumtangent point. ②The lines at the connection of the two rings are in a seamless overlapping structure, ③The lines in the connection of the two rings are in a seamless overlapping structure. At the same time, a connecting metal 9 connecting the two rings is provided at the overlap; the inscribed connection includes: ① the two rings are inscribed and the connecting metal 9 connecting the two rings is set at the inscribed tangent point, ② two circles The lines at the joints of the rings are in a seamless overlapping structure, ③ while the lines at the joints of the two rings are in a seamless overlapping structure, a connecting metal 9 connecting the two rings is arranged at the overlapping positions. Described transparent base sheet 4 can be any transparent material, as long as it can be used as the transparent light window material that satisfies the requirement of using occasion, can simultaneously metal mesh grid 5 be processed on it according to certain technological process; According to technological process, metal mesh The grid 5 can be loaded on the surface of the transparent substrate 4 through the adhesive layer 1; the single-layer or multi-layer anti-reflection 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 long-term exposure of metal parts Cause corrosion and oxidation in the air, reduce the shielding ability, and also prevent the metal grid 5 from being scratched.

The electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings of the present invention, the basic structure of a typical two-dimensional grid composed of two groups of concentric ring pairs overlapping two-dimensional orthogonal arrangement is shown in Figure 2, Among them, two groups of concentric ring pairs are respectively arranged in two-dimensional orthogonal manner, and any one ring in the four adjacent basic rings 6 is adjacent to the other two rings and connected circumscribedly, with the circle center EFGH A square can be formed as a vertex, and the centers of any other four basic rings 6 arranged in this adjacent manner are also a vertex to form a square, that is, the centers of all basic rings 6 form a two-dimensional orthogonal equidistant lattice , such an arrangement ensures that all the basic rings 6 are closely arranged according to the two-dimensional orthogonal distribution; similarly, any one of the four adjacent modulation basic rings 8 is adjacent to the other two rings And the circumscribed connection, a square can be formed with the center of the circle ABDC as the vertex, and the centers of the other four modulated basic circles 8 arranged in this adjacent manner as the vertices also form a square, that is, the centers of all the modulated basic circles 8 A two-dimensional orthogonal equidistant lattice is formed, and such an arrangement ensures that all the modulation basic rings 8 are closely arranged according to the two-dimensional orthogonal distribution. The two-dimensional orthogonal circumscribed circular array formed by the basic ring 6 overlaps the two-dimensional orthogonal circumscribed circular array formed by the modulated basic ring 8 in the above-mentioned manner. Generally, the basic ring 6 and the modulation basic ring 8 may have different diameters, and the arrays formed by them may have different positions and arrangement directions when they are overlapped. As a typical structure, when the two-dimensional orthogonal circumscribed ring arrays composed of two sets of concentric ring pairs shown in Figure 2 are arranged overlappingly, the diameters of the outer rings of the two sets of concentric metal ring pairs are equal, The diameters of the inner rings are also equal, and the inner ring of each modulation unit communicates circumscribed with the four basic rings 6 , and the inner ring of each basic unit communicates circumscribed with the four modulation basic rings 8 . If a sub-ring 7 inscribed inside the basic ring 6 is added in the structure shown in FIG. 2 , this actually constitutes a two-dimensional orthogonal nested array structure of multi-period metal rings.

In the electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings of the present invention, the diameters of the rings in the basic unit and the modulation unit are on the order of millimeters and submillimeters, and the diameters of the rings in the basic unit and the modulation unit are The width of the metal lines is on the order of micron and sub-micron to ensure high light transmittance and good electromagnetic shielding effect. In addition, the two concentric ring pairs and the sub-rings 7 are made of metals 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.

The electromagnetic shielding light window based on the two-dimensional orthogonal nested array of multi-period metal rings of the present invention, as a preferred structural mode, the diameter of the sub-ring 7 in the basic unit is the same, and the diameter of the sub-ring 7 in the basic unit is the same as that of the concentric ring in the basic unit The outer ring of the pair is inscribed and connected, and is connected with the inner ring of the concentric ring pair. The diameter of the sub-ring 7 is equal to the radius difference between the inner and outer rings of the concentric ring pair in the basic unit; The angle formed by the center of the circle and the line connecting the centers of the basic rings 6 is equal: Figure 3 shows the schematic diagrams of several basic units when the sub-rings and the inner rings of the concentric rings are circumscribed, wherein Figure 3 (a) (b) (c) and (d) respectively represent the schematic diagrams of the basic units with the number of sub-rings being 3, 4, 5, and 6.

Fig. 4 and Fig. 5 respectively show that the two circular rings are connected circumscribed or connected internally, and the metals that ensure reliable electrical connection between the tangent points of the metal rings are ensured by overlapping or setting (such as covering) the lines to ensure that the tangent metal rings are connected to each other. Close connection conducts electricity. Among them, Figure 4(a)(b)(c) respectively show the schematic diagrams of the seamless overlapping structure of the two rings when they are circumscribed connected: Figure 4(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 smaller than the center-to-center distance when the two rings are circumscribed, and greater than the difference between the center-to-center distance and the sum of the line widths of the two rings when the two rings are circumscribed. Figure 4(b) is a seamless overlapping In a special case, the inner and outer contours of the two rings circumscribe each other. Figure 4(c) is another special case of seamless overlap. The distance between the centers of the two rings is equal to the distance between the centers of the two rings and the two The difference between the sum of the widths of the ring lines, that is, the inner contours of the two ring lines is circumscribed. In Figure 4(d), since 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 5(a) and (b) respectively show the schematic diagrams of the seamless overlapping structure of two rings when inscribed connected: Figure 5(a) shows the general situation of seamless overlapping of two rings when inscribed connected, that is, two The distance between the centers of the rings is greater than the distance between the centers of the two rings when they are inscribed, and is smaller than 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. Figure 5(b) shows that when the two rings are connected inscribed A special case of seamless overlapping of rings, the distance between the centers of 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 outer contour of the two rings is inscribed. Figure 5(c) shows that the outer contour of the circular ring line with a smaller diameter is inscribed with the inner contour of the larger diameter circular ring line. At this time, it is necessary to set a metal at the tangent point to ensure reliable electrical connection between the tangent points of the metal ring. 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 them to ensure the circumscribed or inscribed communication of the metal rings. And Fig. 4 (d) and Fig. 5 (c) show a kind of preferred metal connection mode at the tangent point, the connecting metal 9 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 fall completely 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.

Fig. 6 and Fig. 7 are the schematic diagrams of the existing square grid structure and its high order diffraction and its relative intensity distribution in US Patent No. 4,871,220 respectively. Its schematic diagram of high-order diffraction and its relative intensity distribution; Figure 10 and Figure 11 are respectively a schematic diagram of the metal grid structure of the preferred scheme A in the present invention and a schematic diagram of its high-order diffraction and its relative intensity distribution, and the metal grid structure of the preferred scheme A The choice of the two-dimensional orthogonal circumscribed ring array overlapping structure shown in Figure 2 is the basic structure. The outer ring diameters of the two sets of concentric ring pairs are equal, and the inner ring diameters are equal; basically When the unit and the modulation basic unit are cross-arranged, the inner ring of each modulation unit is connected with the four basic rings 6 circumscribed, and the inner ring of each basic unit is connected with the four basic modulation rings 8; When a sub-ring is added to the basic unit, the diameter of the sub-ring 7 in the basic unit is the same, and it is connected inscribed with the outer ring of the concentric ring pair in the basic unit, and connected with the inner ring of the concentric ring pair in the basic unit. ; The angle formed by the center of the adjacent sub-ring 7 and the connecting line of the basic ring 6 centers is equal; the number of sub-rings 7 in the adjacent basic unit is the same, and the diameters are equal; each basic unit contains four sub-rings ring, and each sub-ring 7 is inscribed in communication with a basic ring 6 and inscribed with a modulation basic ring 8 .

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 three 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. Compared with the square grid and ring grid, the metal grid structure in the preferred scheme A has significantly lower maximum relative intensity of high-order diffraction, and the number of high-order diffraction spots in the same investigation interval has increased significantly, thus avoiding high-order diffraction The problem that the diffraction energy is concentrated on a small number of diffraction orders makes the distribution of high-order diffraction energy more uniform; Figure 12 shows the specific values of the maximum relative intensity of high-order diffraction for the above three structures. The maximum relative intensity of diffraction is significantly higher than that of other structures, and the maximum relative intensity of high-order diffraction of the metal grid structure corresponding to Scheme A of the present invention has been significantly reduced, from 0.0259% (the high-order of the existing ring grid structure The maximum relative intensity of diffraction) drops to 0.0094%, which is 64%. Metal grid structure.

The composition method of the present invention makes the mesh relatively average, especially the metal grid structure given in the preferred solution, which still has good light transmittance and shielding performance while deeply homogenizing the distribution of high-order diffraction energy. When used to construct a double-layer metal grid structure, it can improve the contradictory problem of light transmittance and shielding efficiency. At the same time, because the single-layer structure of the present invention is deeply homogenized with high-order diffraction energy distribution, it can also solve the existing double-layer structure. Due to the limitation of the single-layer grid structure in the metal grid structure, it is impossible to further homogenize the distribution of high-order diffraction energy.

The metal grid 5 in the electromagnetic shielding light window of the multi-period ring two-dimensional orthogonally nested metal ring array of the present invention can be processed by the following processing method: make a mask by electron beam direct writing, etc., light 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. The mask making process can also be omitted, and the method of laser direct writing can be directly used to make the metal grid pattern of the two-dimensional orthogonally nested metal ring array of multi-period rings. 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 occasion, and can be ordinary glass, quartz glass, infrared material, transparent resin material, etc. The two groups of concentric rings of the present invention are paired with the metal structure of the sub-rings 7 according to the transparent The substrate 4 adopts a suitable processing process to completely cover the transparent substrate 4, and can achieve reliable electrical connection or sealing with the window frame to ensure excellent electromagnetic shielding function. In practical application, the surface of the transparent substrate 4 with the grid structure of the present invention can be plated 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 in the air for a long time Or oxidation to reduce the shielding ability, and also prevent the grid layer from being scratched, worn or otherwise damaged.

Claims (5)

1., based on the electromagnetic shielding optical window of multicycle metal ring two-dimensional quadrature nested array, it is characterized in that: the metallic mesh (5) in electromagnetic shielding optical window by two groups of concentric metal annulus to form by the arrangement of two-dimensional quadrature contiguity arranged evenly respectively and overlapping distributed load in optical window transparent substrate surface; The outer toroid that wherein one group of concentric metal annulus is right as basic annulus (6) containing being communicated with its inscribe, the sub-annulus (7) of metal, the sub-annulus (7) that donut pair is communicated with its inscribe jointly forms the elementary cell of two-dimensional metallic net grid structure and forms basic circle ring array, each basic annulus (6) equal diameters in basic circle ring array and adjacent basic annulus (6) circumscribed connection; The each annulus of another group concentric metal annulus centering forms modulation circle ring array to as modulating unit, and the outer toroid of each modulating unit is as modulating basic annulus (8) equal diameters and the basic annulus of adjacent modulation (8) circumscribed connection; Basic circle ring array forms overlapping distributed architecture with modulation circle ring array; In elementary cell and modulating unit, the diameter of each annulus is millimeter and submillimeter magnitude, and in elementary cell and modulating unit, the metal wire width of each annulus is micron and sub-micrometer scale; Described circumscribed connection comprises: 1. circumscribed the and circumscribed point of contact place of two annulus arranges the connection metal (9) 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 (9) 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 (9) 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 (9) be communicated with by two annulus at overlapping place; The outer toroid equal diameters that in elementary cell and modulating unit, two groups of donuts are right, interior circle diameter is equal, and basic circle ring array and modulation circle ring array is overlapping when arranging, the interior annulus of each modulating unit is communicated with four basic annulus (6) are circumscribed, with four, the interior annulus of each elementary cell modulates that basic annulus (8) is circumscribed to be communicated with, form the nested circle ring array of two-dimensional quadrature.

2. as claimed in claim 1 based on the electromagnetic shielding optical window of multicycle metal ring two-dimensional quadrature nested array, it is characterized in that: the diameter of elementary cell neutron annulus (7) is identical, and right with donut in the elementary cell of place in annulus is circumscribed is communicated with; The angle that the center of circle of adjacent sub-annulus (7) and basic annulus (6) circle center line connecting form is equal; The number of neighboring unit cells neutron annulus (7) is identical, and equal diameters.

3. as claimed in claim 1 based on the electromagnetic shielding optical window of multicycle metal ring two-dimensional quadrature nested array, it is characterized in that: containing four sub-annulus in each elementary cell, and every sub-annulus (7) is all communicated with basic annulus (6) inscribe, modulates basic annulus (8) inscribe be communicated with one.

4. as claimed in claim 1 based on the electromagnetic shielding optical window of multicycle metal ring two-dimensional quadrature nested array, it is characterized in that: two groups of donuts are formed by the alloy that electric conductivity is good with connection metal (9), sub-annulus (7), and alloy thickness is greater than 100nm.

5. as claimed in claim 1 based on the electromagnetic shielding optical window of multicycle metal ring two-dimensional quadrature nested array, it is characterized in that: adhesive linkage (1) chromium or titanium material are formed.