A random pixelated metal mesh and a method of making the same, and a photoelectric payload window

Abstract

This invention relates to the field of metal mesh fabrication technology, specifically providing a randomly pixelated metal mesh and its fabrication method, as well as a photoelectric load window. The random pixelated metal mesh fabrication process utilizes a Python greedy algorithm and a controllable random distribution to generate a square random arrangement pattern. Pixels are then filled along each side of the randomly arranged square units to form a pixelated filling pattern. The resulting random pixelated metal mesh pattern is obtained by performing symmetry and mirroring operations on the pixelated filling pattern. The pixels correspond to the material property of metal. Simulation and fabrication are performed according to the random pixelated metal mesh pattern. This invention achieves rapid, low-cost, and highly flexible fabrication of randomized fine-line metal mesh, realizing a perfect unity between design and physical fabrication.

Description

Technical Field

[0001] This invention belongs to the field of metal mesh processing technology, and particularly relates to a random pixelated metal mesh and its preparation method, and a photoelectric load window. Background Technology

[0002] Electro-optical payloads (OAPs) provide reconnaissance data for aircraft motion decisions, target allocation, and mission assignment by detecting, tracking, and identifying targets and understanding the environmental situation, playing a crucial role in target search, target confirmation, and target tracking. However, due to the transmissivity and cavity effect of the OAP window, the radar cross-section (RCS) of the OAP increases sharply. For example, the RCS of an infrared search and track system with an OAP window diameter of Φ100mm exceeds 0.01m. 2 This will become a strong scattering source for the photoelectric load.

[0003] To solve the problems of electromagnetic shielding and reduced detectability of optical windows, the most direct and effective measure is to load an optically transparent conductive film on the surface of the optical window. After the optically transparent conductive film is prepared on the surface of the optical window, the incident electromagnetic waves can be guided to a non-sensitive direction by the overall shape design of the device, thereby reducing backscattering of electromagnetic waves and forming the ability to reject high-power electromagnetic interference, thus improving the electromagnetic protection level of the whole device.

[0004] The development trend of optoelectronic payload technology is to integrate forward-looking infrared imaging (FLIR), infrared search and track (IRST), and laser pointing and targeting (LTD) to form a new generation of optoelectronic detection systems (EOTS). In this case, the optical window must use a "three-in-one" material, such as multispectral zinc sulfide or zinc selenide. The window material must simultaneously be compatible with high transmittance of laser, mid-wave infrared, and long-wave infrared light without affecting the imaging quality of the optical system.

[0005] Currently, metal mesh gratings are an important technical means to solve the problems of electromagnetic shielding of photoelectric loads and reduce detectability. However, the core contradiction in optical window design lies in the difficulty of simultaneously achieving high light transmittance and strong electromagnetic shielding. Current research on metal mesh gratings mainly focuses on two aspects: low diffraction effects and metal mesh grating manufacturing processes. However, the design and application of metal mesh gratings are based on the following fundamental principles: low resistance and strong electromagnetic shielding. Under the premise of consistent void ratio, the finer the grating linewidth, the stronger the electromagnetic shielding effect. This leads to limitations in existing processes due to the non-standard shape and size of the window and optical diffraction effects. Fine lines are difficult to process and are prone to generating false signals and noise, which seriously affects imaging quality.

[0006] From the perspectives of deterministic optical manufacturing and refined metal mesh manufacturing, laser direct writing, laser-induced printing, and DMD lithography have become the preferred technologies. However, laser-induced metal mesh manufacturing suffers from broken lines and high surface resistance, making it difficult to achieve electromagnetic shielding targets above 20dB. Laser direct writing has significant advantages in manufacturing cycle-based metal meshes, but due to limitations in optical switch technology performance, it cannot manufacture random metal meshes. Furthermore, laser direct writing is a "line" processing technology, resulting in low manufacturing efficiency and high cost. The principle of DMD lithography is as follows: light emitted from the light source is collimated and homogenized before being reflected onto the DMD panel. By controlling the tilt angle of the reflector, the light from the target image is reflected to the projection lens, reduced in size, and then projected onto the photoresist surface. The objective lens and moving platform move along the X and Y axes respectively, achieving large-area pattern exposure. Compared to traditional lithography technologies, DMD lithography reduces mask manufacturing costs. Compared to laser direct writing and electron beam direct writing, it can achieve parallel direct writing, is suitable for large-area processing needs, and offers lower costs and greater flexibility. However, the pixelated processing characteristics of DMD make random metal mesh grids prone to "jagged edges" and "overlapping" problems, especially when manufacturing lines smaller than 5μm, where these problems are more severe. Current randomized metal mesh grid designs mainly include hexagonal and circular random patterns, but both of these random patterns are affected by the randomness factor, making metal mesh grids prone to overlap. These design problems of random mesh grids further exacerbate the "jagged edges" and "overlapping" problems.

[0007] like Figure 1 As shown, where Figure 1 In Figure 'a', the randomly designed metal ring pattern is shown, while in Figure 'b', the actual metal mesh pattern is produced by DMD lithography. Figure 'b' has serious jagged edges and overlapping rings.

[0008] like Figure 2 As shown, c represents the designed hexagonal random mesh pattern, while d is the actual hexagonal random metal mesh pattern produced by DMD lithography. Similarly, the actual hexagonal random metal mesh pattern produced has a severe jagged effect and hexagonal overlap problem caused by the small area of ​​the hexagonal units.

[0009] In addition, the problem of metal line width serration can easily lead to broken metal grid lines, increased surface resistance, and compromised electromagnetic shielding performance of the metal grid. The "overlapping" of the metal grid can easily lead to uneven exposure and poor grid line quality. Especially in the exposure and development stages, repeated experiments are required, resulting in a low grid yield.

[0010] After random metal mesh design, tetrahedral meshes are used. When performing electromagnetic shielding performance simulation calculations on these meshes, the mesh subdivision of the random mesh needs to be refined. When simulating and analyzing fine-line metal meshes, an even finer mesh density is required to accurately discretize the metal mesh, making it difficult to perform simulation calculations on random meshes. Therefore, although existing DMD lithography has solved the problems of high fabrication cost and low fabrication efficiency associated with laser direct writing, DMD lithography technology has inherent serration and overlap defects when manufacturing fine-line random gratings, which severely restricts the engineering application of metal gratings that combine high light transmittance, strong shielding, and high imaging quality. This results in an inefficient unification of the design, simulation, and manufacturing of random metal gratings, meaning that the metal gratings actually fabricated do not match the design goals. Summary of the Invention

[0011] In view of this, the present invention aims to provide a random pixelated metal grid and its preparation method, as well as a photoelectric load window. By using a Python greedy algorithm and controllable random distribution, a random pixelated metal grid without overlap, gaps, or steps is generated. The design and calculation are performed using rectangular grid partitioning technology, ensuring the perfect unity of the design and manufacturing of the random pixelated metal grid.

[0012] To achieve the above objectives, the technical solution created by this invention is implemented as follows: The first aspect of this invention provides a method for fabricating a randomly pixelated metal mesh, comprising: S1: Define a rectangular pixel grid. Using a Python greedy algorithm, arrange square cells of various sizes within the rectangular pixel grid according to the principle of prioritizing larger sizes. The side length of each size of square cell is an integer multiple of the pixel. The number of square cells of each size is randomly distributed in a controlled manner. S2: Extend the mark inward along the edge within each square unit by at least one pixel to form a pixelated fill pattern; S3: Perform symmetrical and / or mirror copying operations on the pixelated fill pattern to obtain a random pixelated metal mesh pattern; S4: Set the pixels of the extended markers within the randomly pixelated metal mesh pattern as ideal conductors, and simulate the electromagnetic shielding effectiveness of the randomly pixelated metal mesh pattern.

[0013] Preferably, a greedy algorithm using Python is used to arrange square cells of various sizes within a rectangular pixel grid, prioritizing larger sizes. Using a Python greedy algorithm, square cells are placed in descending order of size within a rectangular pixel grid, following a scanning order from the bottom left corner to the right and upwards, prioritizing larger sizes. The following constraints are applied to the placement of the square units: Each square cell is completely placed within a rectangular pixel grid, and the square cells do not overlap with each other.

[0014] Preferably, the controllable random distribution includes: the probability of each size of square unit is uniformly distributed, power-law distributed, or normally distributed.

[0015] Preferably, in S2, one pixel is marked inward along the edge within each square unit to form a pixelated fill pattern.

[0016] Preferably, S3 further includes: calculating the empty area ratio of the random pixelated metal mesh pattern.

[0017] Preferably, in step S4, the CAD format file of the randomly pixelated metal mesh pattern is imported into the full-wave analysis software based on the method of moments, and the electromagnetic shielding effectiveness of the randomly pixelated metal mesh pattern is simulated and calculated using the full-wave analysis software based on the method of moments.

[0018] Preferred options also include: S5: Coat the glass surface of the optoelectronic load window with photoresist; S6: Expose the coated workpiece using DMD lithography technology; S7: After development, a metal film is deposited, and after removing the photoresist, a randomly pixelated metal grid is obtained.

[0019] Preferably, the pixel size of the extended mark is the same as the resolution size of the equipment used for DMD lithography.

[0020] A second aspect of the present invention provides a randomly pixelated metal mesh, comprising: preparing it using a method for preparing a randomly pixelated metal mesh.

[0021] The present invention provides a third aspect of a photoelectric load window, comprising: A single-window glass substrate; And, a randomly pixelated metal mesh formed on the surface of the window glass substrate.

[0022] Compared with the prior art, the present invention can achieve the following beneficial effects: This invention aligns the rectangular grid partitioning in the random pixelated metal mesh design process with the pixelated processing dimensions of DMD lithography, directly using manufacturing constraints (the pixelated characteristics of DMD) as the core design rule. This solves the process defects from the source, achieves seamless integration between design and manufacturing, avoids the problem that traditional design patterns need further processing before exposure, effectively improves the simulation calculation efficiency of fine-line random meshes, and avoids the problems of "jaggedness" and "overlapping" of random meshes in DMD processing.

[0023] This invention bypasses the jagged edges and overlaps caused by directly using DMD photolithography to draw continuous curves, and achieves a perfect unity between the design and manufacturing of random pixelated metal mesh, avoiding the problem of discrepancies between the designed pattern and the actual product obtained in traditional methods.

[0024] The randomly pixelated metal mesh of this invention can achieve linewidths at the DMD resolution level. The linewidth of the pixelated random metal mesh can reach 1μm, which, compared to the existing conventional 5μm processing capability, improves the electromagnetic shielding effectiveness of the metal mesh from 48dB to 62dB, providing strong support for electromagnetic shielding of photoelectric loads. Furthermore, while traditional transparent conductive films such as graphene and oxides can achieve 95% light transmittance and 62dB shielding, they struggle to achieve high light transmittance in the mid-wave or long-wave infrared range. In contrast, the randomly pixelated metal mesh of this invention can achieve high light transmittance in the visible, laser, mid-wave infrared, and long-wave infrared ranges.

[0025] This invention employs DMD lithography technology and solves the problems of "sawtooth" and "overlap" in DMD lithography. It has advantages such as high processing efficiency, low manufacturing cost, and high manufacturing flexibility. Compared with the crack template method, it has the advantages of non-contact lithography processing and deterministic manufacturing capability. Compared with laser direct writing, it has the ability to process randomized metal mesh patterns. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a comparison image of the design pattern and the actual fabricated object of the traditional random circular metal mesh fabrication based on DMD lithography in the background technology; Figure 2 This is a comparison image of the design pattern and the actual fabricated object of the traditional DMD lithography-based fabrication of random hexagonal metal mesh in the background technology; Figure 3 This is a schematic diagram of a random arrangement of squares generated by a Python greedy algorithm and a controllable random distribution, provided according to an embodiment of the present invention. Figure 4 This is a schematic diagram of a pixelated fill pattern provided according to an embodiment of the present invention; Figure 5 This is a random pixelated metal mesh pattern and a partial magnified view provided according to an embodiment of the present invention; Figure 6 This is a comparison chart of the simulation curves of electromagnetic shielding effectiveness of three linewidth metal mesh grids in the range of 1~18GHz with a 95% empty area, provided by an embodiment of the present invention. Figure 7This is a comparison diagram of the normalized diffraction intensity distribution of a randomly pixelated metal mesh grating and a periodically rectangular metal mesh grating, provided according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; the relevant operations can be fully understood based on the description in the specification and general technical knowledge in the art.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0032] In Embodiment 1 of the present invention, a method for preparing a random pixelated metal mesh grid is provided, including the following steps: S1: Define a rectangular pixel grid, and arrange square units of various sizes in the rectangular pixel grid according to the principle of preferentially large sizes by using the Python greedy algorithm. The side length of each square unit of each size is an integer multiple of the pixel; the number of square units of each size adopts a controllable random distribution; S2: Expand and mark at least 1 pixel inward along the side in each square unit to form a pixelated filling pattern; S3: Perform symmetric and / or mirror copying operations on the pixelated filling pattern to obtain a random pixelated metal mesh grid pattern; S4: Set the pixels expanded and marked in the random pixelated metal mesh grid pattern as ideal conductors, and simulate and calculate the electromagnetic shielding effectiveness of the random pixelated metal mesh grid pattern Among them, the specific content in step S1 includes the following: First, define a rectangular pixel grid, use it to design and generate a part of the random pixelated metal mesh grid. After generating a part of the random pixelated metal mesh grid in the rectangular pixel grid, through copying operations such as symmetry, mirroring, rotation, and central symmetry, copy the patterns generated in multiple rectangular pixel grids to obtain a random pixelated metal mesh grid pattern. Therefore, the size requirements of the rectangular pixel grid are: the length and width of the random pixelated metal mesh grid to be designed and prepared are integer multiples of the rectangular pixel grid.

[0033] The rectangular pixel grid is a regular rectangular grid with a division width of W and a length of H. Each smallest basic unit is called a pixel, and its coordinates are represented by an integer pair (x, y), where x is the abscissa (0 ≤ x < W), and y is the ordinate (0 ≤ y < H). Then the pixel coordinates in the lower left corner of the rectangular pixel grid are fixed at (0, 0), and the upper right corner is (W, H).

[0034] The size of the pixels needs to be designed according to the DMD lithography equipment used in the subsequent actual manufacturing process, ensuring that the pixel size is the same as the resolution size of the DMD lithography equipment. Taking a DMD lithography equipment with a resolution of 1μm as an example, the side length of the pixel is also selected as 1μm.

[0035] As Figure 3 shown, after defining the rectangular pixel grid, a Python greedy algorithm is used to arrange square units of various sizes within the rectangular pixel grid according to the principle of prioritizing large sizes. Specifically, the arrangement of square units is carried out in the Python environment, and the size of each square unit is generated using the Python greedy algorithm. The size of each square unit is determined by the following process: First, a two-dimensional occupancy matrix G is introduced, and its value is defined as follows: G(x,y) = 0 indicates that the grid has not been occupied by any square unit and is in an idle state; G(x,y) = 1 indicates that the grid has been occupied by a certain square unit.

[0036] At the initial stage of the rectangular pixel grid, all G(x,y) are 0. In the computer, it directly corresponds to a Numpy two-dimensional array.

[0037] During the generation process of square units, each square unit is uniquely determined by three parameters: The lower left coordinate (x0,y0) of each square; The side length s (a positive integer, s≥1); The square unit precisely covers an s×s pixel area from (x0,y0) to (x0 + s - 1,y0 + s - 1).

[0038] And the following constraints are imposed on the placement position of the square unit: When placing any square unit, it must simultaneously meet the following two hard constraints. One is the boundary constraint, that is, all parts of the square unit must be completely located inside the rectangular pixel grid, that is, 0≤x0≤x0 + s - 1<W and 0≤y0≤y0 + s - 1<H. The other is the non-overlap constraint, that is, all pixels covered by the square unit must be in an unoccupied state (G(x,y)=0) at the current moment. Only when both of these constraints are met can the square unit be legally placed. This mathematical model ensures that the generated pattern is completely legal and geometrically repeatable and verifiable, and is convenient for subsequent computer programming implementation.

[0039] Then, a controlled random distribution is used to determine the size and number of squares, rather than a fixed size. During the scanning process, the greedy algorithm prioritizes the largest possible square cell at the current position, considering it as the largest possible square cell. The side length of this largest square cell is the maximum legal side length. However, this maximum value is not directly used during the generation of cells in the positive direction. Instead, it is used as the upper limit s_max, and the random generation function generate_size(s_max) is called to generate a candidate size s (1≤s≤s_max). The upper and lower limits of the size can be manually adjusted. The random generation function supports the following three controlled random distributions: Uniform distribution: The probability of each size of the square unit appearing is exactly the same, which is suitable for scenarios that require uniform diversity; Power-law distribution: The probability of small or large sizes is controlled by the parameter power_k. For example, when power_k=6, it is biased towards larger sizes. The proportion of small sizes can be increased by manually reducing power_k. This distribution pattern is highly consistent with the distribution of grains and porous media in nature. Normal distribution: The size is concentrated around a certain average value, which is suitable for engineering applications that require control over the overall "thickness".

[0040] The resulting size s is constrained by the current local geometric constraints (the maximum size that can be placed by the greedy algorithm) and also introduces a pre-defined randomness, thus achieving controllable random filling within the greedy framework. The combination of the greedy algorithm and controllable random distribution ensures both the diversity and unpredictability of the patterns generated by the arrangement of square units, and guarantees complete filling and connectivity through subsequent placement rules.

[0041] The above square cell generation process is implemented by computer, employing a hybrid strategy of "greedy algorithm + random algorithm" to divide the process into two closely connected stages: Phase 1: Prioritize placing larger square cells (main fill phase). The scanning order strictly follows the sequence of starting from the bottom left corner, scanning from left to right, and scanning from bottom to top (outer loop y from 0 to H-1, inner loop x from 0 to W-1).

[0042] First, find the first unoccupied cell (x,y) (G(x,y)=0), and calculate the maximum possible side length s_max of this position in the current state: first take the maximum value allowed by the boundary max_possible=min(Wx,Hy), and then check the size (x,y,size) that can be placed down from this value until the first legal size is found (ensuring that occupied cells are taken into account).

[0043] Next, based on the preset random distribution, taking a uniform distribution as an example, the random generation function generate_size(s_max) is called to generate a candidate size s (1≤s≤s_max).

[0044] Then, immediately place the square cell and mark all the covered cells as occupied (G=1), and record the result.

[0045] Finally, repeat the first stage process described above until the entire rectangular pixel grid has been scanned.

[0046] The second stage: Filling the remaining gaps (refinement stage). The entire rectangular pixel grid is scanned again, and all remaining unoccupied cells are filled one by one with 1×1 small squares, ensuring the entire area is 100% gap-free. This stage prioritizes using larger squares, which significantly improves filling efficiency, reduces subsequent fragmentation, and retains sufficient randomness. The entire algorithm is simple, deterministic, and can be fully automated, guaranteeing that the final result meets all four core requirements under any valid input parameters.

[0047] Specifically, step S2 includes the following: After completing the random arrangement of square patterns in step S1, the side length of each square unit is an integer multiple of pixels. Each square unit is filled along its four sides without gaps or overlap. For any square unit in the random arrangement pattern, starting from the bottom left corner, a marker is added one pixel inwards. For any square unit with a side length of 's', a marker is added one pixel inwards along the sides of the square unit, starting from the bottom left corner. This includes bottom marker filling, right marker filling, top marker filling, and left marker filling. The internal area of ​​the square unit remains empty, without any filling or marker pixels. Figure 4 As shown, the pattern formed in this way is a set of square ring structures composed of metal pixel units, with each ring having a line width of 1 pixel unit. This square ring structure is called a pixelated fill pattern.

[0048] As an optional embodiment, the markings extend inward along the edge of each square unit by more than 2 pixels, that is, the width of the square ring structure is greater than or equal to 2 pixels.

[0049] Specifically, step S3 includes the following: Using the pixelated fill pattern obtained in step S2 as the base template, after performing symmetrical and / or mirror copying operations, a pattern is obtained as follows: Figure 5The random pixelated metal mesh pattern shown is generated by Python. After generating the random pixelated metal mesh pattern, the empty ratio of the random pixelated metal mesh pattern is given, that is, the proportion of unmarked fill pixels to all pixels in the rectangular pixel grid. The pixel side length is 1 micrometer. The designed random pixelated metal mesh pattern is then exported as a CAD format file.

[0050] Step S4 specifically includes the following: Import the CAD file from step S3 into a full-wave analysis software based on the method of moments (MM), such as FEKO. After importing, model and analyze the randomly pixelated metal mesh pattern, calculating its electromagnetic shielding effectiveness. First, set the pixels of the extended markers in the randomly pixelated metal mesh pattern as ideal conductors, corresponding to the areas of subsequent metal deposition. Then, in FEKO's mesh generation module, without any additional refinement or adaptive meshing, force the mesh size to be equal to the side length of the pixel; that is, one pixel in the randomly pixelated metal mesh pattern corresponds to one actual pixel in the DMD lithography process.

[0051] Because each pixel in the randomized pixelated metal mesh pattern is a square, and all pixel units are aligned according to the grid, the simulation model in FEKO perfectly matches the CAD design pattern, requiring no post-processing or geometric approximation. This is a significant advantage over existing technologies that require a large number of refined meshes to accurately describe fine lines. The number of meshes is greatly reduced, computational efficiency is multiplied, and no additional errors are introduced by geometric discretization, ensuring a perfect correspondence between the design pattern and the actual manufactured object, avoiding the problem of "mismatch between the product and the design" in traditional processing.

[0052] Specifically, step S5 includes the following: Positive photoresist is applied to the glass surface of any photoelectric load window using either spin coating or ultrasonic spraying. The recommended photoresist thickness is 0.8~1μm. Ultraviolet positive photoresist, model BP212, is recommended. Spin coating is recommended for circular photoelectric load windows, while ultrasonic spraying is recommended for irregularly shaped photoelectric load windows.

[0053] Specifically, step S6 includes the following: The photoelectric load window glass surface coated with photoresist is exposed using traditional DMD lithography. The DMD resolution is selected from the pixel size of the randomly pixelated metal mesh pattern, i.e., 1 micrometer × 1 micrometer. The exposure mode is traditional DMD scanning exposure. After exposure, it is developed using a 5‰ NaOH solution.

[0054] Specifically, step S7 includes the following: A metal film is deposited on the developed photoelectric load window glass using vacuum coating technology. The metal film can be made of materials such as gold, copper, or aluminum, and the thickness of the metal film is controlled at 500 nm. After coating, the adhesive is removed from the photoelectric load window glass. At this point, the random pixelated metal grid designed in step S4 can be obtained on the surface of the photoelectric load window glass without the problems of jaggedness and overlap, thus achieving a perfect unity between the design and manufacturing of the random pixelated metal grid.

[0055] In Embodiment 2 of the present invention, a random pixelated metal grid is provided, which is prepared by the random pixelated metal grid preparation method in Embodiment 1. It includes: a metal grid, the grid being composed of square metal pixels, the pixels being arranged continuously and without overlap.

[0056] In Embodiment 3 of the present invention, a photoelectric load window is provided, including a window glass substrate and a randomly pixelated metal grid disposed on its surface. The randomly pixelated metal grid is the same as the randomly pixelated metal grid in Embodiment 2.

[0057] The randomly pixelated metal mesh prepared by the method for preparing the randomly pixelated metal mesh provided in Embodiment 1 of this invention has been practically verified. First, as... Figure 6 The experiment shown verifies the electromagnetic shielding effectiveness of three randomly pixelated metal mesh grids with different linewidths within the 1–18 GHz range, with a 95% empty area ratio. Curve A in the figure represents the electromagnetic shielding effectiveness of a randomly pixelated metal mesh grid with a linewidth of 1 μm and a 95% empty area ratio, ranging from 37 dB to 62 dB; Curve B represents the electromagnetic shielding effectiveness of a randomly pixelated metal mesh grid with a linewidth of 2.5 μm and a 95% empty area ratio, ranging from 29 dB to 54 dB; and Curve C represents the electromagnetic shielding effectiveness of a randomly pixelated metal mesh grid with a linewidth of 5 μm and a 95% empty area ratio, ranging from 23 dB to 48 dB. Therefore, under the premise of the same empty area ratio, the finer the linewidth, the higher the electromagnetic shielding effectiveness. This invention enables the creation of a randomly pixelated metal mesh with a linewidth of 1μm, achieving an electromagnetic shielding efficiency of up to 62dB, which is approximately 14dB higher than the conventional 5μm linewidth (maximum 48dB), thus greatly enhancing electromagnetic shielding capabilities.

[0058] like Figure 7The experiment shown verifies the normalized diffraction intensity distribution of the randomly pixelated metal mesh grating prepared in this invention compared to that of the traditional periodic rectangular metal mesh grating. In the figure, the horizontal axis represents the 100mm width range of the metal mesh grating, and the vertical axis represents the normalized diffraction intensity amplitude. Curve D represents the normalized diffraction intensity distribution of the periodic rectangular metal mesh grating; curve E represents the normalized diffraction intensity distribution of the randomly pixelated metal mesh grating prepared in this invention. The 50mm position represents its principal maximum diffraction, and other positions represent higher-order diffraction. The randomly pixelated metal mesh grating of this invention suppresses diffraction without sacrificing transmittance. A comparison of curves D and E shows that, under the premise of maintaining the principal maximum unchanged, the randomly pixelated metal mesh grating effectively suppresses higher-order diffraction of the periodic rectangular metal mesh grating, solving the problem of concentrated higher-order diffraction in the traditional periodic grating.

[0059] In summary, the above description is merely a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

[0060] The systems, apparatuses, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, a computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0061] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. A method of making a random pixelated metal mesh, characterized in that, include: S1: Define a rectangular pixel grid. Using a Python greedy algorithm, arrange square cells of various sizes within the rectangular pixel grid according to the principle of prioritizing larger sizes. The side length of each size of square cell is an integer multiple of the pixel. The number of square cells of each size is randomly distributed in a controllable manner. S2: Extend the mark inward along the edge within each square unit by at least one pixel to form a pixelated fill pattern; S3: Perform symmetrical and / or mirror copying operations on the pixelated fill pattern to obtain a random pixelated metal mesh pattern; S4: Set the pixels of the extended markers within the random pixelated metal mesh pattern as ideal conductors, and simulate and calculate the electromagnetic shielding effectiveness of the random pixelated metal mesh pattern.

2. The method for preparing a randomly pixelated metal mesh according to claim 1, characterized in that, The method utilizes a Python greedy algorithm to arrange square cells of various sizes within a rectangular pixel grid, prioritizing larger sizes. Using a Python greedy algorithm, square cells are placed in descending order of size within the rectangular pixel grid, following a scanning order from the bottom left corner to the right and upwards, prioritizing larger sizes. The following constraints are applied to the placement of the square units: Each square cell is completely placed within the rectangular pixel grid, and the square cells do not overlap with each other.

3. The method for preparing a randomly pixelated metal mesh according to claim 1, characterized in that, The controllable random distribution includes: the probability of each size of square unit is uniform, power-law, or normal.

4. The method for preparing a randomly pixelated metal mesh according to claim 1, characterized in that, In step S2, a pixel is marked inward along the edge within each square unit to form a pixelated fill pattern.

5. The method for preparing a randomly pixelated metal mesh according to claim 1, characterized in that, S3 further includes: calculating the empty area ratio of the random pixelated metal mesh pattern.

6. The method for preparing a randomly pixelated metal mesh according to claim 1, characterized in that, In step S4, the CAD format file of the random pixelated metal mesh pattern is imported into a full-wave analysis software based on the method of moments, and the electromagnetic shielding effectiveness of the random pixelated metal mesh pattern is simulated and calculated using the full-wave analysis software based on the method of moments.

7. The method for preparing a randomly pixelated metal mesh according to claim 1, characterized in that, Also includes: S5: Coat the glass surface of the optoelectronic load window with photoresist; S6: Expose the photoelectric load window glass after resist coating using DMD lithography; S7: After development, a metal film is deposited, and after removing the photoresist, a randomly pixelated metal grid is obtained.

8. The method for preparing a randomly pixelated metal mesh according to claim 7, characterized in that, The pixel size of the extended marker is the same as the resolution size of the equipment used in DMD lithography.

9. A randomly pixelated metal mesh, characterized in that, It is prepared by the method for preparing random pixelated metal mesh as described in any one of claims 1 to 8.

10. A photoelectric payload window, characterized in that, include: A single-window glass substrate; And, as described in claim 9, a randomly pixelated metal mesh formed on the surface of the window glass substrate.

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