CN103813701B - Double-deck triangle and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window - Google Patents

Abstract

The tangent annulus array electric magnetic screen optical window of double-deck triangle and quadrature hybrid distribution belongs to electromangnetic spectrum field, electromagnetic shielding optical window is rotated to be staggered by double layer of metal net grid and loads on optical window both sides and form, every layer of metallic mesh presses equilateral triangle and two-dimensional quadrature mixing arrangement contiguity arrangement formation by the metal ring of the circumscribed connection of same diameter as basic annulus, be provided with in each basic annulus be communicated with its inscribe, the sub-annulus of metal, both form the elementary cell of two-dimensional mesh grid array structure jointly; In the junction of the tangent connection of annulus, overlapping or the metal ensureing reliably to electrically connect between metal ring tangent point is set by lines, guarantee that all annulus conduct electricity mutually.By choosing of Double-level Reticulated grid alternate angle, metallic mesh structure of the present invention significantly can reduce the inhomogeneities of net grid Advanced Diffraction light distribution, and the stray light that diffraction is caused distribution is more even, less to Imaging; Choose suitable substrate thickness, good electromagnetic shielding efficiency can be obtained.

Description

Double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window

technical field

The invention belongs to the field of electromagnetic shielding of optical transparent parts, in particular to a double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window.

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. This 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 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 optical window with a latitude and longitude metal grid structure realized by metal grid technology and conformal optical window technology The electromagnetic shielding 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 due to the effect of the ring, the structure can make the high-order diffraction distribution of the grid uniform and achieve low side lobes. Imaging is beneficial.

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 After the effect 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, a double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window are developed to achieve depth homogenization and extremely low imaging quality for high-order diffraction. The purpose of the impact, but also has a good electromagnetic shielding efficiency.

The technical scheme adopted in the present invention is: adopt a double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, and place two layers of metal grids in parallel on both sides of the transparent substrate or substrate of the light window , the two layers of metal grids have the same unit shape and structural parameters, the two layers of metal grids are rotated and staggered, and each layer of metal grids is made of a metal ring with the same diameter as the basic ring according to the equilateral triangle and two-dimensional regular The cross-mixed arrangement is closely arranged and loaded on the transparent substrate of the light window or the surface of the substrate; the adjacent basic rings are circumscribed and connected, and the connecting lines between the centers of the adjacent basic rings form an equilateral triangle or square, and each adjacent equilateral Between triangles, between adjacent squares, or between adjacent equilateral triangles and squares share a side or a common apex; each basic ring is provided with a sub-ring connected to its inscribed, metal, the basic ring The sub-rings inscribed with it together constitute the basic unit of the two-dimensional metal grid structure; the diameters of the basic rings and sub-rings are on the order of millimeters and submillimeters, and the basic rings and sub-rings are The width of the metal lines is on the order of microns and submicrons; the rotation and staggered arrangement means that when the metal grids on both sides of the transparent substrate or the substrate are placed asymmetrically, there is relative rotation between the two layers of metal grids, The relative rotation angle is a staggered angle; 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 , 3. while the lines of the two rings are in a seamless overlapping structure, a connecting metal connecting the two rings is set at the overlap; the inscribed connection includes: ① two rings are inscribed and the inscribed tangent point A connecting metal connecting the two rings is provided at the joint, ② the lines at the joint of the two rings are in a seamless overlapping structure, ③ the lines at the joint of the two rings are in a seamless overlapping structure, and at the same time, two Connecting metal connected by rings.

As a preferred basic structure, the above-mentioned double-layer triangular and orthogonal mixed distribution rings and sub-ring array electromagnetic shielding light windows, the connecting lines between the centers of the adjacent basic rings form an equilateral triangle or a square, any of which A square shares a side or a vertex with at least one equilateral triangle, and any equilateral triangle shares a side or a vertex with at least one square.

For the above-mentioned double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, 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.

In the above-mentioned double-layer triangular and orthogonal mixed distribution rings and sub-ring array electromagnetic shielding light windows, the adjacent sub-rings in the basic unit are circumscribed or intersected.

As a preferred structure, the above-mentioned double-layer triangular and orthogonal mixed distribution rings and sub-ring array electromagnetic shielding light windows, the diameters of the sub-rings in the basic unit are the same, and the center of the adjacent sub-rings and the basic The included angles formed by the lines connecting the centers of the circles are equal.

As a preferred structure, the above-mentioned double-layer triangular and orthogonal mixed distribution rings and sub-ring array electromagnetic shielding light windows, the number of sub-rings in the different basic units is the same, and the diameters are equal.

As a preferred structure, the above-mentioned double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, the relative positions of the sub-rings in the different basic units are the same, and after being copied by one basic unit A single-layer metal grid is formed by an equilateral triangle and a two-dimensional orthogonal mixed arrangement.

As a preferred structure, the above-mentioned double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, the relative positions of the sub-rings in the adjacent basic units are different, and the two-dimensional metal mesh In the grid, a basic unit is copied and arranged closely in an equilateral triangle and a two-dimensional orthogonal mixed arrangement, wherein any basic unit is rotated by a certain angle around the center of its own basic ring in a two-dimensional plane relative to its adjacent basic unit.

The above-mentioned double-layer triangular and orthogonal mixed distribution rings and sub-ring array electromagnetic shielding light windows, the basic rings, sub-rings and connecting metals are composed of alloys with good electrical conductivity, and the thickness of the alloy is greater than 100nm.

For the above-mentioned double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, the metal grid and the transparent substrate material of the light window are bonded by an adhesive layer composed of chromium or titanium material.

For the above-mentioned double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, the selection range of the stagger angle of the double-layer metal mesh grid is 1°～29°, 31°～59°, 61° ~89°.

For the above-mentioned double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, the thickness of the transparent substrate or substrate with double-layer metal mesh grid is less than 5mm.

The innovation and good effect of the present invention are:

The innovation of the present invention lies in that the two layers of metal grids are rotated and staggered, and each layer of metal grids is composed of metal rings with the same diameter as the basic rings, which are arranged closely in an equilateral triangle and two-dimensional orthogonal mixed arrangement. Loaded on the transparent substrate of the light window or the surface of the substrate; the adjacent basic rings are circumscribed and connected, and the lines connecting the centers of adjacent basic rings form equilateral triangles or squares. Between adjacent equilateral triangles and between adjacent squares Occasionally or adjacent equilateral triangles and squares share sides or common vertices; each basic ring is provided with a metal sub-ring connected to its inscribed part, and the sub-ring connected to its inscribed part is provided in each basic ring Together constitute the basic unit of the two-dimensional metal grid structure; the diameters of the basic ring and the sub-ring are on the order of millimeters and submillimeters, and the metal line widths of the basic ring and the sub-rings are microns and sub-millimeters. micron level; said rotation and staggered arrangement means: when the transparent substrate or the metal grids on both sides of the substrate are placed asymmetrically, there is relative rotation between the two layers of metal grids, and the relative rotation angle is the staggered angle; The circumscribed connection includes: ① the two rings are circumscribed and the connecting metal connecting the two rings is set at the circumtangent point; ② the lines at the joint of the two rings are in a seamless overlapping structure; While the lines are in a seamless overlapping structure, a connecting metal connecting the two rings is arranged at the overlap; the inscribed connection includes: ① two rings are inscribed and a metal connecting the two rings is set at the inscribed tangent point. Connect the metal, 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, a connecting metal connecting the two rings is set at the overlap. 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:

For a single-layer metal grid, the basic rings are arranged in an equilateral triangle or orthogonal arrangement as the basic arrangement, which can overcome the shortcomings of the concentrated distribution of high-order diffraction energy existing in the traditional grid metal grid, and has good homogenization and advanced The characteristics of the sub-diffraction energy distribution, and the use of basic rings arranged in an equilateral triangle and an orthogonal mixed arrangement to form a metal ring array can effectively adjust the high-order diffraction energy distribution of the metal grid array structure to achieve uniformity. The purpose of optimizing the energy distribution of high-order diffraction is one of the reasons why the metal grid of the present invention homogenizes the energy distribution of high-order diffraction.

The basic unit is formed by adding sub-rings to the basic ring, 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 comparison of high-order diffraction energy 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; at the same time, while ensuring the same light transmittance, it is necessary to further increase the diameter of the basic ring, from On the whole, the high-order diffraction energy of each array is reduced; and because the high-order diffraction generated by the sub-annular array structure and the high-order diffraction of the basic annular array structure have a very low probability of superposition; especially after further optimizing the parameters, their energy is relatively low. The high-order diffractions do not superimpose, thereby homogenizing the energy distribution of the high-order diffractions, which is the second reason why the metal grid of the present invention homogenizes the energy distribution of the high-order diffractions.

Each basic unit can be rotated at a certain angle around the center of the corresponding 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, which can To further homogenize the energy distribution of the higher-order diffraction, this is the third reason for the metal grid of the present invention to homogenize the energy distribution of the higher-order diffraction.

When the above-mentioned metal grid is used to construct a double-layer metal grid with staggered angles, because the substrate between the double-layer metal grids has a very low influence on the light transmission performance, and the overall structure of the double-layer metal grid is ensured. When the light transmittance is the same as that of the single-layer metal grid before construction, it is necessary to increase the diameter of each ring of the single-layer metal grid used to construct the double-layer metal grid, which results in two layers of the double-layer metal grid The energy distribution of the high-order diffraction orders of the metal grid is significantly reduced. When the two-layer metal grid forms a double-layer grid, the high-order diffraction with higher energy of the two-layer grid is effectively avoided due to the rotation and staggered arrangement. The superposition of the order averages the energy distribution of the high-order diffraction order as a whole, which is the fourth reason why the metal grid of the present invention averages the energy distribution of the high-order diffraction order.

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 metal ring structure closely arranged by the basic ring and the sub-ring structure effectively improve the uniformity of the metal ring grid structure, and the basic unit is centered on the center of the basic ring corresponding to the basic unit. When rotating at a certain angle, while effectively modulating the energy distribution of high-order diffraction orders, it basically does not affect the electromagnetic shielding effect, and even improves the electromagnetic shielding effect in some preferred solutions. In particular, when a single-layer metal grid is used to form a double-layer metal grid, the electromagnetic coupling between the double-layer metal grids is very strong, which can significantly improve the electromagnetic shielding efficiency.

Description of drawings

Fig. 1 is a schematic cross-sectional view of a preferred structure of a double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window.

Fig. 2 is a schematic diagram of a typical structure of basic circular rings arranged in close contact with equilateral triangles and two-dimensional orthogonal mixed arrangements.

Fig. 3 is a schematic diagram of an optimal structure of a basic unit composed of a basic ring and a sub-ring.

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 a rotation mode of the basic unit of the present invention

Fig. 7 is a schematic diagram of the existing square grid structure.

Fig. 8 is a schematic diagram of high-order diffraction and its relative intensity distribution of existing square grids.

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

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

Fig. 11 is a schematic diagram of the metal grid structure of preferred solution A in the present invention.

Fig. 12 is a schematic diagram of the higher order diffraction and its relative intensity distribution of the preferred single-layer metal grid A in the present invention.

Fig. 13 is a schematic diagram of the structure of double-layer symmetrically arranged metal grids in the present invention.

Fig. 14 is a schematic diagram of high-order diffraction and relative intensity distribution of double-layer symmetrically arranged metal grids in the present invention.

Fig. 15 is a schematic diagram of the structure of double-layer staggered metal grids in the present invention.

Fig. 16 is a schematic diagram of high-order diffraction and its relative intensity distribution of double-layer staggered metal grids in the present invention.

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

Part number description in the picture: 1. AR coating 2. Protective layer 3. Metal grid 4. Adhesive layer 5. Transparent substrate 6. Adhesive layer 7. Metal grid 8. Protective layer 9. AR coating 10 .Basic ring 11. Sub-ring 12. Connecting metal

Detailed ways

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

Double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, two layers of metal grids are placed in parallel on both sides of the transparent substrate or substrate of the light window, and the two layers of metal grids have the same unit shape and structural parameters, the two layers of metal grids 3 and 7 are rotated and staggered, and each layer of metal grids is composed of metal rings of the same diameter as the basic rings 10, which are arranged closely in an equilateral triangle and two-dimensional orthogonal mixed arrangement. and loaded on the transparent substrate of the light window or the surface of the substrate; the adjacent basic rings 10 are circumscribed and connected, and the connecting lines between the centers of the adjacent basic rings 10 form equilateral triangles or squares, and between adjacent equilateral triangles, Between adjacent squares or between adjacent equilateral triangles and squares, there is a common side or a common apex; in each basic ring 10, there is a metal sub-ring 11 connected to its inscribed circle, and the basic ring 10 and its inner The connected sub-rings 11 together constitute the basic unit of the two-dimensional metal grid structure; the diameters of the basic rings 10 and the sub-rings 11 are on the order of millimeters and submillimeters, and the basic rings 10 and the sub-rings The width of the metal lines of the ring 11 is on the order of micrometers and submicrometers; the rotation and staggered arrangement means that when the metal grids on both sides of the transparent substrate or the substrate are placed asymmetrically, there is a gap between the two layers of metal grids. Relative rotation, the relative rotation angle is a staggered angle; the circumscribed communication includes: 1. the two rings are circumscribed and the connecting metal 12 connecting the two rings is arranged at the circumtangent point; Seam overlapping structure, ③ two circular rings are in the seamless overlapping structure at the joint line, at the same time, a connecting metal 12 connecting the two circular rings is set at the overlap; the inscribed connection includes: ① two circular rings The connecting metal 12 connecting the two rings is set at the tangent and inscribed point, ② the lines at the joint of the two rings are in a seamless overlapping structure, ③ the lines at the connecting point of the two rings are in a seamless overlapping structure, and at the same time, the The connecting metal 12 connecting the two rings is arranged at the overlap. Fig. 1 is a schematic cross-sectional view of a preferred structure of a double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window, the transparent substrate 5 can be any transparent material, as long as it can meet the requirements of the application occasion The required transparent light window material can process the metal grid 3 and 7 on it according to a certain process flow; according to the process flow, the metal grid 3 and the transparent substrate 5 are connected through the adhesive layer 4, and the metal grid 7 It is connected with the transparent substrate 5 through the adhesive layer 6; the single-layer or multi-layer anti-reflection film 1 and 9 enhance the light transmission ability of the light window, and the single-layer or multi-layer protective layer 2 and 8 are 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 grids 3 and 7 from being scratched. In practical application, transparent substrate 5 also can be transparent substrate, is used for processing two-layer metal mesh grid on its both sides, and transparent substrate or substrate, two-layer metal mesh grid 3 and 7 are indispensable for the present invention. According to the process and actual application, the adhesive layers 4 and 6, the anti-reflection films 1 and 9, and the protective layers 2 and 8 may or may not be available.

In the double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window of the present invention, the metal grids 3 and 7 have the same unit shape and structural parameters. Each layer of metal grid is composed of metal rings of the same diameter as basic rings 10 arranged in close contact with equilateral triangles and two-dimensional orthogonal mixed arrangements and loaded on the transparent substrate of the light window or the surface of the substrate. The basic rings 10 The distribution of is shown in Figure 2. The diameters of each basic ring 10 are equal and circumscribed. The adjacent basic rings are arranged in an equilateral triangle or two-dimensional orthogonal arrangement. Between adjacent equilateral triangles and between adjacent squares Occasionally or between adjacent equilateral triangles and squares share sides or share vertices. In Figure 2, the lines connecting the centers of adjacent basic circles form squares or equilateral triangles, and A, B, C, D, E, F, and G are respectively arbitrary The centers of the seven adjacent basic rings, the quadrilateral ABCD is a square, the triangle ADE and the triangle EFG are equilateral triangles, this arrangement ensures that the same diameter circumscribed and connected basic rings 10 are orthogonal to equilateral triangles and two-dimensional The mixed arrangement and close arrangement form a single-layer metal grid and are loaded on the surface of the transparent substrate of the light window. As a preferred structure, when the line connecting the centers of adjacent basic rings 10 constitutes an equilateral triangle or a square, any square shares at least one side or a common apex with one equilateral triangle, and any equilateral triangle shares at least one side with a square. edge or common vertex.

In the double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window of the present invention, each basic ring 10 has a sub-ring 11 inscribed with the ring, and the basic ring 10 and its inner The connected sub-rings 11 together form the basic unit of the two-dimensional grid structure. The diameter of the basic ring 10 and the sub-ring 11 is on the order of millimeters and submillimeters, and the width of the metal lines of the basic ring 10 and the sub-rings 11 is on the order of microns and sub-microns, so as to ensure high light transmittance and good electromagnetic shielding effect . In addition, the basic ring 10, the sub-ring 11 and the connecting metal 12 are made of alloys 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 double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window of the present invention, the number of 11 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 angle formed by the center of 11 and the line connecting the centers of the basic ring 10 is any angle, and the sub-rings 11 in different basic units are rings of equal diameter or non-equal diameter, and the numbers are the same or different; adjacent in the basic unit The sub-rings 11 are circumscribed and connected or intersected. Fig. 3 shows a schematic diagram of an optimal structure of a basic unit composed of a basic ring and a sub-ring. In Fig. 3, the diameters of the sub-rings in the basic unit are the same, and the included angles formed by the centers of adjacent sub-rings and the lines connecting the centers of the basic rings are equal. Figure 3(a)(b) is the circumscribed connection of the sub-rings 11 of the same diameter in the basic unit, and Figure 3(c)(d) is the intersecting connection of the sub-rings 11 of the same diameter in the basic unit.

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 with a smaller diameter is inscribed with the inner contour of the larger diameter circular ring. 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 shown in Fig. 4 (d) and Fig. 5 (c) is a kind of optimal metal connection mode at the tangent point, the connecting metal 12 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, in order to achieve the purpose of homogenizing the stray light caused by high-order diffraction, as a preferred solution, the diameters of the sub-rings 11 in the basic unit are the same, and the centers of the adjacent sub-rings 11 and the center of the basic ring 10 are connected. The included angles formed by the lines are equal; on this basis, the number of 11 sub-rings in different basic units is the same, and the diameters are equal. As a special example of this preferred scheme, the relative positions of the sub-rings 11 in different basic units are the same, and after being copied from one basic unit, they are closely arranged in an equilateral triangle and two-dimensional orthogonal mixed arrangement to form a metal grid 3 or 7 . In order to achieve the stray light effect caused by good homogenization of high-order diffraction, as another special case of this preferred solution, the sub-rings 11 in the adjacent basic units in the single-layer metal mesh grid 3 and 7 arrays in the present invention The relative positions are different, and they are copied from a basic unit in a two-dimensional grid array and arranged in a triangular and orthogonal mixed distribution, wherein any basic unit surrounds itself in a two-dimensional plane relative to its adjacent basic unit. The center of circle is rotated at a certain angle; for example, Fig. 6 is a schematic diagram of a rotation mode of the basic unit of the present invention relative to the adjacent basic unit, wherein the basic unit of the single-layer metal grid is selected to be communicated circumscribed by five sub-rings 11 with the same diameter, Ensure that the included angle formed by the center of the adjacent sub-ring 11 and the line connecting the center of the basic ring 10 is equal, and the basic unit is rotated by 18° relative to the adjacent basic unit.

Fig. 7 and Fig. 8 are respectively the schematic diagrams of the existing grid structure of the US Patent No. 4871220 and its high order diffraction and its relative intensity distribution. Its high-order diffraction and its relative intensity distribution diagram; Fig. 11 and Fig. 12 are the schematic diagram of the metal grid structure of preferred scheme A in the present invention and its high-order diffraction and its relative intensity distribution schematic diagram respectively, the metal grid in preferred scheme A It is a single-layer grid structure. The basic ring shown in Figure 2 is selected as a typical structure formed by an equilateral triangle and a two-dimensional orthogonal mixed arrangement. Five sub-rings are added to the basic ring to form a basic unit as shown in Figure 3 ( In the structure shown in b), the adjacent basic units in a certain area are rotated according to the rotation method shown in Figure 6, and the rotation angle is 22.5°. Fig. 13 and Fig. 14 are respectively the schematic diagram of double-layer symmetrically arranged metal grid structure and its high-order diffraction and its relative intensity distribution schematic diagram in the present invention, the two-layer metal grid structure adopts the single-layer grid structure of preferred scheme A, and Symmetrically arranged on both sides of the transparent substrate 5; Figure 15 and Figure 16 are respectively a schematic diagram of the double-layer staggered metal grid structure and a schematic diagram of its high-order diffraction and its relative intensity distribution in the present invention, and the two-layer metal grid structure is still selected The single-layer grid structure of the preferred scheme A, but the rotation is staggered on both sides of the transparent substrate 5, and the stagger angle α is 20°. The stagger angle refers to that when the two layers of metal grids on both sides of the transparent substrate are composed When the arrangement becomes a rotation and staggered arrangement, the angle at which one layer of the metal grid is rotated relative to the other layer of the metal grid in its plane is the relative rotation angle when the two layers of the grid are rotated and staggered.

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 five 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. The single-layer metal grid structure and double-layer grid structure of the preferred scheme A are significantly lower than the grid and ring grids, and the relative intensity of the highest-order diffraction is significantly reduced, and the number of high-order diffraction spots in the same investigation interval is obvious. increase, 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; Figure 17 is the specific value of the maximum relative intensity of the high-order diffraction of the above five structures. The maximum relative intensity of the higher-order diffraction of the metal grid structure is obviously higher than that of other structures, and the maximum relative intensity of the higher-order diffraction of the metal grid structure corresponding to the preferred scheme A has been significantly reduced, from 0.0259% (the existing circular ring network The maximum relative intensity of high-order diffraction of the grid structure) drops to 0.0025%, which is 90%, and the homogenization effect of high-order diffraction is obvious; Consistent, from 0.0259% (the maximum relative intensity of the higher-order diffraction of the existing circular ring grid structure) to 0.0025%, a reduction of 90%, and the introduction of the rotation staggered arrangement further reduces the maximum relative intensity of the higher-order diffraction, from 0.0025% is reduced to 0.0006%, a reduction of 76%, which is 98% lower than the maximum relative intensity of the high-order diffraction of the existing ring grid structure, and the depth averaging of the high-order diffraction is completed. To sum up, the double-layer staggered metal grid structure of the present invention has a remarkable effect on homogenizing the distribution of high-order diffraction energy, which is not only superior to the grid metal grid structure existing in US Patent No. ring metal grid structure.

In the double-layer triangular and orthogonal mixed distribution ring and sub-ring array electromagnetic shielding light window of the present invention, the staggered angle of the double-layer metal grid can have many preferred ranges, for example, when the staggered angle of the double-layer metal grid is selected When the range is 1°～29°, 31°～59°, 61°～89°, it can achieve excellent homogeneous high-order diffraction energy distribution effect; and the double-layer grid spacing, that is, the transparent substrate Or the thickness of the substrate, when properly selected, can significantly enhance the electromagnetic shielding efficiency, for example, when the transparent substrate with a double-layer metal grid or the thickness of the substrate is less than 5mm, good shielding efficiency can be obtained in the low-frequency microwave band.

The metal grids 3 and 7 in the double-layer triangular and orthogonal mixed distribution rings and sub-ring array electromagnetic shielding light windows of the present invention can be processed and manufactured by the following processing method: make a mask by electron beam direct writing, etc., The transparent substrate 5 of the light window is cleaned and then plated with chrome or titanium as the adhesive layers 4 and 6, coated with a metal film, then coated with photoresist, and photoetched using a processed mask, and finally dry or wet. Etching by the method, and the grid pattern is obtained after the glue is removed. It is also possible to omit the mask making process, and directly use the method of laser direct writing to make the metal grid pattern of the triangular and orthogonal mixed distribution rings and 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 5 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 basic ring 10 and sub-ring 11 metal structures of the present invention will be based on the transparent substrate. 5. Adopt appropriate processing technology to make it completely cover the transparent substrate 5, and realize reliable electrical connection or sealing with the window frame to ensure excellent electromagnetic shielding function. In practical applications, the transparent substrate 5 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 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 (12)

1. double-deck triangle and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, at the both sides parallel placement double-level-metal net grid of optical window transparent substrate or substrate, double-level-metal net grid have identical unit profile and structural parameters, it is characterized in that: double-level-metal net grid (3,7) rotate and be staggered, and every layer of metallic mesh forms and load on optical window transparent substrate or substrate surface as basic annulus (10) by equilateral triangle and the arrangement of two-dimensional quadrature mixing arrangement contiguity by the metal ring of same diameter; The circumscribed connection of adjacent basic annulus (10), the circle center line connecting of adjacent basic annulus (10) forms equilateral triangle or square, is total to limit or common summit between each adjacent equilateral triangle, between adjacent square or between adjacent equilateral triangle and square; Be provided with in each basic annulus (10) be communicated with its inscribe, the sub-annulus (11) of metal, the sub-annulus (11) that described basic annulus (10) is communicated with its inscribe forms the elementary cell of two-dimensional metallic net grid structure jointly; Described basic annulus (10) is millimeter and submillimeter magnitude with the diameter of sub-annulus (11), and described basic annulus (10) is micron and sub-micrometer scale with the metal wire width of sub-annulus (11); Described rotation is staggered and refers to: when the metallic mesh of transparent substrate or substrate both sides is by asymmetric placement, has relative rotation between double-level-metal net grid, and relative rotation angle is alternate angle; Described circumscribed connection comprises: 1. circumscribed the and circumscribed point of contact place of two annulus arranges the connection metal (12) 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 (12) 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 (12) 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 (12) be communicated with by two annulus at overlapping place.

2. double-deck triangle according to claim 1 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, it is characterized in that: the circle center line connecting of adjacent basic annulus (10) forms equilateral triangle or square, wherein arbitrary square is at least total to limit or common summit with an equilateral triangle, and arbitrary equilateral triangle is at least total to limit or common summit with a square.

3. double-deck triangle according to claim 1 and 2 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, it is characterized in that: in each elementary cell, sub-annulus (11) number is more than or equal to 2, and diameter is identical or different, the angle that the center of circle of adjacent sub-annulus (11) and basic annulus (10) circle center line connecting form is arbitrarily angled, sub-annulus (11) in different elementary cell is equal diameter or non-equal diameter annulus, and number is identical or different.

4. double-deck triangle according to claim 1 and 2 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, is characterized in that: the circumscribed connection of adjacent sub-annulus (11) or intersect in elementary cell.

5. double-deck triangle according to claim 3 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, it is characterized in that: the diameter of elementary cell neutron annulus (11) is identical, the angle that the center of circle of adjacent sub-annulus (11) and basic annulus (10) circle center line connecting form is equal.

6. double-deck triangle according to claim 5 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, is characterized in that: sub-annulus (11) number in different elementary cell is identical, equal diameters.

7. double-deck triangle according to claim 6 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, it is characterized in that: sub-annulus (11) relative position in different elementary cell is identical, and form single-layer metal net grid by equilateral triangle and the arrangement of two-dimensional quadrature mixed distribution arrangement contiguity after an elementary cell copies.

8. double-deck triangle according to claim 6 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, it is characterized in that: sub-annulus (11) relative position in neighboring unit cells is different, and by equilateral triangle and the arrangement of two-dimensional quadrature mixing arrangement contiguity after being copied by an elementary cell in two-dimensional metallic net grid, wherein any one elementary cell rotates to an angle around self basic annulus (10) center of circle in two dimensional surface relative to its neighboring unit cells.

9. double-deck triangle according to claim 1 and 2 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, it is characterized in that: described basic annulus (10), sub-annulus (11) and connection metal (12) are made up of the alloy that electric conductivity is good, and alloy thickness is greater than 100nm.

10. double-deck triangle according to claim 1 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, is characterized in that: the adhesive linkage formed with chromium or titanium material between metallic mesh with optical window transparent substrate is bonding.

11. double-deck triangles according to claim 1 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, is characterized in that: the stagger angle selection range of double-level-metal net grid at 1 ° ~ 29 °, 31 ° ~ 59 °, 61 ° ~ 89 °.

12. double-deck triangles according to claim 1 and quadrature hybrid distribution annulus and sub-circle ring array electromagnetic shielding optical window, is characterized in that: be less than 5mm with the transparent substrate of double-level-metal net grid or substrate thickness.