Random curve mesh and generation method thereof

Abstract

The invention belongs to the technical field of electromagnetic shielding optical window design, and particularly relates to a random curve mesh and a generation method thereof, the random curve mesh is used for an electromagnetic shielding optical window, the mesh is a metal mesh, the mesh structure is composed of a plurality of random curves, and the random curve mesh structure can effectively inhibit high-order diffraction energy.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic shielding optical window design, and in particular relates to a random curve grid and a generation method thereof. Background Art

[0002] As the requirements for stealth performance of aviation equipment continue to increase, optical windows must not only have high transmittance in the visible to infrared band, but also have strong electromagnetic shielding performance in the microwave range. To this end, the method adopted in the industry is to plate a transparent conductive film or metal grid on the optical window. The metal grid is a mesh microstructure with a grid period of millimeters or sub-millimeter levels, which can simultaneously achieve high transmittance in a wide band from near-infrared to visible light and electromagnetic shielding in the microwave band, and has gradually become one of the most effective and potential technical means in optical window electromagnetic shielding technology.

[0003] Typical metal grid structures are periodic square grid and periodic circular ring metal grid. The periodic square grid has a directional structure, which will form a highly concentrated distribution of high-order diffraction energy on the imaging plane, seriously affecting the imaging quality. In comparison, the periodic circular ring metal grid has a weakened high-order diffraction energy, and has better light transmittance and electromagnetic shielding performance. However, the periodic grid structure cannot avoid the problem of high-order diffraction energy concentration. Summary of the invention

[0004] In view of this, in order to further improve the performance of the metal grid and average the high-order diffraction energy, the present invention provides a random curve grid and a generation method thereof, wherein the random curve grid structure can effectively suppress the high-order diffraction energy.

[0005] The technical solution of the present invention is:

[0006] A random curve mesh is used for electromagnetic shielding optical windows. The mesh is a metal mesh, and the mesh structure is composed of a plurality of random curves.

[0007] The present invention also proposes a random curve grid structure generation method for generating the above-mentioned random curve grid, comprising the following steps:

[0008] Step 1: Polygon generation: According to the requirements of electromagnetic shielding efficiency, polygons with a certain duty cycle are designed within the specified length and width dimensions, and each polygon is numbered, and the sequence number and vertex coordinates of each polygon are stored;

[0009] Step 2: Random curve conversion: Use quadratic Bezier curves to interpolate the adjacent vertices of each polygon to convert the straight edges of each polygon into random curves, where the coordinates of the control points of the quadratic Bezier curves are random;

[0010] Step 3: Graphics drawing: The random curves of two adjacent vertices are stored with the vertex numbers as the numbers, and the length values ​​of the random curves are stored at the same time; random curves are drawn according to the numbering sequence of the polygons to form a closed curve that is connected end to end; then the closed curve is offset to its own center by half the design line width to form a new closed curve that is equidistant from the original closed curve, and the area enclosed by the original closed curve and the new closed curve forms a metal mesh area.

[0011] Furthermore, when drawing a random curve, the number of the random curve that has been drawn is queried to determine whether it is a repeated drawing; if it is a repeated drawing, the previously drawn random curve that is repeated is referenced.

[0012] Furthermore, after step 3, the following steps are further included:

[0013] Step 4: Duty cycle calculation: After the grid is drawn, the length values ​​of all random curves are accumulated to obtain the total length L, and the duty cycle D = 1-L*W / S is calculated according to the line width W, where S is the total area; determine whether the duty cycle meets the design requirements. If not, return to step 1 to adjust the duty cycle of the polygon.

[0014] 5. The method for generating a random curve grid structure according to claim 2, characterized in that after step 4, the method further comprises:

[0015] Step 5: Graphic array: Flip the drawn grid layout of the specified size left and right with the side as the axis of symmetry to form a mirrored graphic, and splice the grid layout and the mirrored graphic together; then flip the spliced ​​graphic up and down with the bottom as the axis of symmetry to form a layout unit related to the grid layout; then periodically array the layout units to obtain a grid layout of the required size.

[0016] Furthermore, in step 1, the arrangement of the polygon vertices is in a counterclockwise order;

[0017] Furthermore, in step 2, the random method of the control point position of the quadratic Bezier curve is: a circular area is generated with the midpoint of two adjacent vertices as the center, and the control point position coordinates are randomly selected in the circular area;

[0018] Furthermore, the randomness of the random curve is adjusted by modifying the radius of the circular area.

[0019] Compared with the existing random grid structure, the advantages of the present invention are:

[0020] 1) The present invention converts the straight edge of the polygon into a random curve, so that the higher-order diffraction stray light is weaker and the central symmetry of the 0th-order diffraction spot is better;

[0021] 2) The present invention can further improve randomness and optical transmittance based on various random polygons;

[0022] 3) The method of the present invention can generate large-size layout files. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the design process of the present invention;

[0025] Figure 2 This is a schematic diagram of a random curve grid structure of Example 1 of the present invention;

[0026] Figure 3 This is a schematic diagram of the random curve grid structure of Example 2 of the present invention;

[0027] Figure 4 The diffraction energy distribution diagram of the quadrilateral grid is consistent with the periodic line width of the curve in Example 1;

[0028] Figure 5 This is the diffraction energy distribution diagram of Example 1 of the present invention;

[0029] Figure 6 The diffraction energy distribution diagram of the polygonal grid with the same periodic line width as the curve in Example 2;

[0030] Figure 7 This is the diffraction energy distribution diagram of Example 2 of the present invention. DETAILED DESCRIPTION

[0031] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0032] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0033] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0034] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The illustrations only show components related to the present disclosure rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0035] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0036] In one embodiment of the present invention, a random curve grid is provided for electromagnetic shielding of an optical window. Figure 2 and Figure 3 The grid is a metal grid, and the grid structure is composed of multiple random curves.

[0037] In one embodiment, the present invention further proposes a random curve grid structure generation method for generating the above-mentioned random curve grid, such as Figure 1 As shown, the following steps are included:

[0038] Step 1: Polygon generation: According to the requirements of electromagnetic shielding efficiency, polygons with a certain duty cycle are designed within the specified length and width dimensions, and each polygon is numbered, and the sequence number and vertex coordinates of each polygon are stored;

[0039] Step 2: Random curve conversion: Use quadratic Bezier curves to interpolate the adjacent vertices of each polygon to convert the straight edges of each polygon into random curves, where the coordinates of the control points of the quadratic Bezier curves are random;

[0040] Step 3: Graphics drawing: The random curves of two adjacent vertices are stored with the vertex numbers as the numbers, and the length values ​​of the random curves are stored at the same time; random curves are drawn according to the numbering sequence of the polygons to form a closed curve that is connected end to end; then the closed curve is offset to its own center by half the design line width to form a new closed curve that is equidistant from the original closed curve, and the area enclosed by the original closed curve and the new closed curve forms a metal mesh area.

[0041] In this embodiment, when drawing a random curve, the number of the random curve that has been drawn is queried to determine whether it is a repeated drawing; if it is a repeated drawing, the previously drawn random curve that is repeated is referenced.

[0042] In this embodiment, the step 3 further includes:

[0043] Step 4: Duty cycle calculation: After the grid is drawn, the length values ​​of all random curves are accumulated to obtain the total length L, and the duty cycle D = 1-L*W / S is calculated according to the line width W, where S is the total area; determine whether the duty cycle meets the design requirements. If not, return to step 1 to adjust the duty cycle of the polygon.

[0044] In this embodiment, the step 4 further includes:

[0045] Step 5: Graphic array: Flip the drawn grid layout of the specified size left and right with the side as the axis of symmetry to form a mirrored graphic, and splice the grid layout and the mirrored graphic together; then flip the spliced ​​graphic up and down with the bottom as the axis of symmetry to form a layout unit related to the grid layout; then periodically array the layout units to obtain a grid layout of the required size.

[0046] In this embodiment, in step 1, the polygon vertices are arranged in a counterclockwise direction;

[0047] In this embodiment, in step 2, the random method of the control point position of the quadratic Bezier curve is: a circular area is generated with the midpoint of two adjacent vertices as the center, and the control point position coordinates are randomly selected in the circular area;

[0048] In this embodiment, the randomness of the random curve is adjusted by modifying the radius of the circular area.

[0049] This embodiment can be described based on the following steps

[0050] The steps to generate a random curve grid structure are as follows:

[0051] Step 1: Polygon generation: According to the requirements of electromagnetic shielding efficiency, polygons with a certain duty cycle are designed within the specified length and width dimensions, including quadrilaterals, hexagons, random hexagons or Thiessen polygons, and the polygons are numbered and their serial numbers and vertex coordinates are stored. The vertices of the polygons are sorted in a counterclockwise direction;

[0052] Step 2: Randomizing the curve: Use a quadratic Bezier curve to interpolate the adjacent vertices of the polygon, where the control point coordinates of the quadratic Bezier curve are random. The randomization method of the control point position of the quadratic Bezier curve is: a circular area is formed with the midpoint of two adjacent vertices as the center, and the control point position coordinates are randomly selected in the area. The degree of randomness is adjusted by modifying the radius of the circular area;

[0053] Step 3: Graphics drawing: Random curves of two adjacent vertices are stored with vertex numbers as numbers, and their length values ​​are stored at the same time; random curves are drawn one by one in the order of polygon numbers to form a closed curve connected end to end, and then the curve is offset toward the center by half the design line width to form a new curve equidistant from the original curve. The area enclosed by the two curves is the metal grid area;

[0054] Step 4: Duty cycle calculation: add up the length values ​​of all random curves to get the total length L, calculate the duty cycle D = 1-L*W / S according to the line width W, where S is the total area; determine whether the duty cycle meets the design requirements. If not, return to step 1 to adjust the input parameters;

[0055] Step 5: Graphic array: Flip the drawn layout of the specified size left and right with the side as the axis of symmetry to form a graphic that is a mirror image of the original layout, and then splice the two together. Then flip it upside down with the bottom as the axis of symmetry to form a layout unit related to the original layout. Then periodically array the unit to obtain the required layout size.

[0056] Example 1

[0057] For a random metal grid mask with a size of 100*100mm, the design requires a period range of about 200μm, a line width of 4.5μm, and a 0th order diffraction transmittance of more than 92%. The layout design generation process is as follows:

[0058] Step 1: Polygon generation:

[0059] 1) Generate a quadrilateral mesh in an area of ​​25mm*25mm, with a side length of 200μm. Store the number and vertex coordinates of each quadrilateral in the quadrilateral mesh through a structure to form a structure array {Rectangle};

[0060] Step 2: Randomize the curve:

[0061] 1) Use quadratic Bezier curves to interpolate adjacent vertices of quadrilaterals one by one in the order of quadrilateral numbers, where the coordinates of the control points of the quadratic Bezier curve are random. The random method of the control point position of the quadratic Bezier curve is: a circular area is formed with the midpoint of two adjacent vertices as the center, and the control point position coordinates are randomly selected in the area, and the diameter of the circular area is the distance between the two vertices;

[0062] Step 3: Curve drawing:

[0063] 1) Draw random curves one by one in the order of the quadrilateral numbers to form a closed curve that is connected end to end, and then shift the curve toward the center by half the design line width, i.e., 2.25 μm, to form a new curve that is equidistant from the original curve. The area enclosed by the two curves is the metal grid area;

[0064] 2) When drawing the curve, the random curves between two adjacent vertices are numbered with the vertex numbers and stored as a list S, and their length values ​​are stored at the same time;

[0065] 3) When drawing the next quadrilateral, first search for a curve with the same number in the curve list S. If there is one, call its coordinates and draw it, and clear the curve from the list S. If not, generate it according to the method in step 2 and store it in the list S;

[0066] Step 4: Duty cycle calculation:

[0067] 1) Accumulate the length values ​​of the curve to get the total length L, and calculate the duty cycle D = 1-L*W / S according to the line width W, where S is the total area; the relationship between the 0th order diffraction transmittance and the duty cycle is T = D*D, and determine whether the transmittance meets the design requirements. If not, return to step 1 to adjust the modified side length and continue the calculation.

[0068] Step 5: Graphics Array:

[0069] 1) The 25mm*25mm layout is first flipped left and right with the side as the axis of symmetry to form a mirror image of the original layout, and the two are spliced ​​together. Then it is flipped up and down with the bottom as the axis of symmetry to form a 50mm*50mm layout unit. Then the unit is periodically arrayed to obtain the required 100mm*100mm layout.

[0070] According to the above method, a quadrilateral grid with a side length changed to a random curve was designed and processed. Its diffraction spot is as follows Figure 5 As shown, the diffraction spot of the corresponding quadrilateral grid is as follows Figure 4 As shown, it can be seen by comparison that the result of this embodiment no longer has obvious "cross line" strong diffraction characteristics, and the averaging effect is good.

[0071] Example 2

[0072] For a random metal grid mask with a size of 100*100mm, the design requires a period range of 90-150μm and a 0th order diffraction transmittance of more than 92%. The layout design generation process is as follows:

[0073] Step 1: Polygon generation:

[0074] 1) Generate a Delaunay triangular mesh in an area of ​​25mm*25mm. The side length of the triangle varies in the range of 90-150μm. Each triangle in the triangular mesh is stored in a structure with its number and vertex coordinates to form a structure array {Delaunay};

[0075] 2) Using the vertex of the triangle as the index, calculate the coordinates of the center of the circumscribed circle of the triangle containing the vertex, and connect them in a counterclockwise order to generate a polygon. Store the polygon in the order of the index as a structure array {Polys};

[0076] Step 2: Randomize the curve:

[0077] 1) Use quadratic Bezier curves to interpolate adjacent vertices of polygons one by one in the order of polygon indexes, where the coordinates of the control points of the quadratic Bezier curve are random. The random method of the control point position of the quadratic Bezier curve is: a circular area is formed with the midpoint of two adjacent vertices as the center, and the control point position coordinates are randomly selected in the area, and the diameter of the circular area is the distance between the two vertices;

[0078] Step 3: Curve drawing:

[0079] 1) Draw random curves one by one in the order of polygon numbers to form a closed curve that is connected end to end, and then offset the curve toward the center by half the design line width to form a new curve that is equidistant from the original curve. The area enclosed by the two curves is the metal grid area;

[0080] 2) When drawing the curve, the random curves between two adjacent vertices are numbered with the vertex numbers and stored as a list S, and their length values ​​are stored at the same time;

[0081] 3) When drawing the next polygon, first search for a curve with the same number in the curve list S. If there is one, call its coordinates and draw it, and clear the curve from the list S. If not, generate it according to the method in step 2 and store it in the list S;

[0082] Step 4: Duty cycle calculation:

[0083] 1) Accumulate the length values ​​of the curve to get the total length L, and calculate the duty cycle D = 1-L*W / S according to the line width W, where S is the total area; determine whether the duty cycle meets the design requirements. If not, return to step 1 to adjust the length of the triangle side and continue the calculation.

[0084] Step 5: Graphics Array:

[0085] 1) The 25mm*25mm layout is first flipped left and right with the side as the axis of symmetry to form a mirror image of the original layout, and the two are spliced ​​together. Then it is flipped up and down with the bottom as the axis of symmetry to form a 50mm*50mm layout unit. Then the unit is periodically arrayed to obtain the required 100mm*100mm layout.

[0086] According to the above method, a polygonal grid with a side length changed to a random curve was designed and processed. Its diffraction spot is as follows: Figure 7 As shown, the diffraction spot of the corresponding polygonal grid is as follows Figure 6 As shown, by comparison, it can be seen that the "star-shaped" diffraction feature of the result of this embodiment is weaker and the homogenization effect is better.

[0087] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A random curve grid, characterized in that: Used for electromagnetic shielding optical window, the grid is a metal grid, and the grid structure is composed of multiple random curves.

2. A method for generating a random curve grid structure according to claim 1, characterized in that: The following steps are involved: Step 1: Polygon generation: According to the requirements of electromagnetic shielding efficiency, polygons with a certain duty cycle are designed within the specified length and width dimensions, and each polygon is numbered, and the sequence number and vertex coordinates of each polygon are stored; Step 2: Random curve conversion: Use quadratic Bezier curves to interpolate the adjacent vertices of each polygon to convert the straight edges of each polygon into random curves, where the coordinates of the control points of the quadratic Bezier curves are random; Step 3: Graphics drawing: The random curves of two adjacent vertices are stored with the vertex numbers as the numbers, and the length values ​​of the random curves are stored at the same time; random curves are drawn according to the numbering sequence of the polygons to form a closed curve that is connected end to end; then the closed curve is offset to its own center by half the design line width to form a new closed curve that is equidistant from the original closed curve, and the area enclosed by the original closed curve and the new closed curve forms a metal mesh area.

3. The method for generating a random curve grid structure according to claim 2, characterized in that: When drawing a random curve, the number of the random curve that has been drawn is queried to determine whether it is a repeated drawing; if it is a repeated drawing, the previously drawn random curve that is repeated is referenced.

4. The method for generating a random curve grid structure according to claim 3, characterized in that: After step 3, the following steps are also included: Step 4: Duty cycle calculation: After the grid is drawn, the length values ​​of all random curves are accumulated to obtain the total length L, and the duty cycle D = 1-L*W / S is calculated according to the line width W, where S is the total area; determine whether the duty cycle meets the design requirements. If not, return to step 1 to adjust the duty cycle of the polygon.

5. The method for generating a random curve grid structure according to claim 4, characterized in that: After step 4, the following steps are also included: Step 5: Graphic array: Flip the drawn grid layout of the specified size left and right with the side as the axis of symmetry to form a mirrored graphic, and splice the grid layout and the mirrored graphic together; then flip the spliced ​​graphic up and down with the bottom as the axis of symmetry to form a layout unit related to the grid layout; then periodically array the layout units to obtain a grid layout of the required size.

6. The method for generating a random curve grid structure according to claim 5, characterized in that: In step 1, the polygon vertices are arranged in a counterclockwise direction.

7. The method for generating a random curve grid structure according to claim 6, characterized in that: In step 2, the random method of the control point position of the quadratic Bezier curve is: a circular area is generated with the midpoint of two adjacent vertices as the center, and the control point position coordinates are randomly selected in the circular area.

8. The method for generating a random curve grid structure according to claim 7, characterized in that: The randomness of the random curve is adjusted by modifying the radius of the circular area.

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