A method for manufacturing a special-shaped large-area metal mesh optical window and the window

Abstract

The application relates to a special-shaped large-area metal mesh optical window and a manufacturing method thereof, and belongs to the field of optical windows. The method comprises the following steps: manufacturing a substrate in a primary mechanical processing mode, coating photoresist on the surface of the substrate, manufacturing a mask opposite to a preset metal mesh shape on the substrate, etching a metal mesh groove, plating a metal mesh layer on the surface of the optical substrate of the metal mesh groove, plating a protective layer on the surface of the metal mesh layer to obtain a preliminary optical window, manufacturing a special-shaped large-area substrate in a secondary mechanical processing mode, stripping and cleaning a non-mesh area, then spraying a layer of photoresist on the surface of the special-shaped large-area substrate, etching a metal mesh special-shaped edge of the special-shaped large-area substrate to form an edge mesh groove, plating an edge metal mesh layer on the surface of the substrate of the edge mesh groove, plating an edge protective layer on the surface of the edge metal mesh layer, stripping and cleaning a core area, and the application has the technical effects of guaranteeing the manufacturing efficiency and uniformity of the special-shaped large-area metal mesh and being suitable for large-area and large-batch production requirements.

Description

Technical Field

[0001] This application relates to the technical field of optical windows, and in particular to an irregularly shaped large-area metal mesh optical window and its manufacturing method. Background Technology

[0002] With the rapid development of radio science and radio frequency technology, a large amount of electromagnetic pollution is generated, which not only interferes with related equipment but also has negative impacts on human health. To eliminate these negative effects, electromagnetic shielding materials and technologies have emerged, especially in the aerospace field. Electromagnetic shielding technology based on metal mesh optical windows enables photoelectric detection systems inside the instrument compartments or work bays of aircraft, missiles, and other aircraft to perform photoelectric detection and reconnaissance of the external environment. Currently, metal mesh optical windows are developing towards irregular shapes and large areas, placing higher demands on the metal mesh fabrication process of the optical window substrate surface.

[0003] Traditional photolithography-based fabrication of large-area irregularly shaped metal mesh optical windows suffers from unevenness in the homogenization of the irregular substrate, leading to inconsistent mesh linewidths on the final optical window surface and consequently affecting the electromagnetic shielding effect. Patent CN109769387A discloses a method for fabricating a multi-layered metal mesh electromagnetic shielding optical window using femtosecond laser etching. This method involves embedding the metal mesh on a substrate material using femtosecond laser etching. However, this method is inefficient, unsuitable for mass production, and produces numerous burrs on the mesh lines, making process control difficult and ultimately impacting the electromagnetic shielding effect of the optical window. Patent CN115023129A discloses an embedded metal mesh optical window and its fabrication method, which utilizes a filler material layer and a protective layer to protect the metal mesh and prevent it from detaching.

[0004] Regarding the aforementioned technologies, the inventors believe that when there is a demand for the production of large-area, high-volume metal mesh window substrates made of various materials, the production efficiency and uniformity cannot be guaranteed. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides an irregularly shaped large-area metal mesh optical window and its manufacturing method.

[0006] One of the objectives of this application is to provide a method for fabricating an irregularly shaped, large-area metal mesh optical window, which employs the following technical solution:

[0007] A method for creating an irregularly shaped, large-area metal mesh optical window includes:

[0008] A large circular base is produced by initial machining, which includes one or more of the following processes: mechanical cutting, grinding, and polishing.

[0009] Photoresist is coated on the surface of a large circular substrate, and a mask with the opposite shape to the preset metal mesh is fabricated on the large circular substrate.

[0010] Etch a metal mesh groove; deposit a metal mesh layer on the optical substrate surface of the metal mesh groove, and deposit a protective layer on the surface of the metal mesh layer to obtain a preliminary optical window;

[0011] Large-area irregularly shaped substrates are produced by further machining, including cutting and polishing processes.

[0012] The non-grid area is stripped and cleaned, and then a layer of photoresist is sprayed onto its surface.

[0013] An edge mesh trench is formed by etching the edges of a large-area irregularly shaped metal mesh substrate. An edge metal mesh layer is deposited on the surface of the optical substrate of the edge mesh trench; and an edge protective layer is deposited on its surface; and...

[0014] The core area was peeled off and cleaned to form a large, irregularly shaped base.

[0015] By adopting the above technical solution, metal mesh trenches are first fabricated on a large circular substrate using methods such as mask fabrication and plasma beam etching. The metal layer and protective layer are then filled into the trenches using vacuum deposition. Finally, an irregularly shaped large-area substrate is obtained through machining, which can significantly improve the uniformity of the metal mesh linewidth on its surface.

[0016] Preferably, the plating of the metal mesh layer includes:

[0017] A metal mesh layer is deposited on the surface of an optical substrate with etched metal mesh grooves using a vacuum deposition method. The material of the metal mesh layer includes one or more of the following metal materials: Ni (nickel), Cr (cadmium), Cu (copper), Ag (silver), Au (copper), and Al (aluminum), or a transparent conductive oxide, or a multilayer conductive film composed of a metal thin film and a transparent conductive oxide.

[0018] Preferably, before forming edge grid grooves at the edge of the irregularly shaped large-area substrate, an edge region is created on the optical substrate by one or more of the following methods: exposure, development, and cleaning, wherein the width of the edge region is less than 1 mm.

[0019] By adopting the above technical solution, through secondary exposure, development, stripping and cleaning, edge ohmic connection metal lines with a width of less than 1mm can be obtained. While ensuring good conductivity of the metal mesh layer, the effective area of ​​irregular large-area substrates is also increased.

[0020] Preferably, before coating the surface of a circular or irregularly shaped large-area substrate with photoresist, the circular or irregularly shaped large-area substrate is cleaned with an ultrasonic cleaner. The cleaned circular or irregularly shaped large-area substrate is then placed on a hot plate for pre-baking to remove most of the moisture adsorbed on the substrate surface. After pre-baking, the substrate is placed at room temperature.

[0021] Preferably, the edge metal mesh layer is made of the same material as the metal mesh layer.

[0022] Preferably, the method of stripping and cleaning the non-grid area, followed by spraying a layer of photoresist onto its surface, includes:

[0023] A photoresist of a predetermined thickness is applied by placing a glue spraying device at the metal mesh window.

[0024] The second objective of this application is to provide an irregularly shaped, large-area metal mesh optical window, which adopts the following technical solution:

[0025] An irregularly shaped large-area metal mesh optical window includes an irregularly shaped large-area substrate, a mesh groove, a metal mesh layer, and a protective layer. The mesh groove is a microstructure groove below the surface of the irregularly shaped large-area substrate. The metal mesh layer fills the mesh groove, and the protective layer is attached to the upper surface of the irregularly shaped large-area substrate.

[0026] Preferably, the irregularly shaped large-area substrate has a polygonal irregular shape, a thickness greater than 3mm, and a maximum diagonal length greater than 10 inches.

[0027] Preferably, the irregularly shaped large-area substrate is made of one of the following materials: HK9L, quartz, microcrystalline, ZNS, ZNSE, Si, Ge, sapphire, and magnesium fluoride.

[0028] Preferably, the projected shape of the metal mesh groove is one or more of a periodically arranged square array, circular array, honeycomb array, and irregular mesh pattern; the metal mesh layer includes a plurality of periodically arranged mesh units, and each mesh unit is interconnected without being separated.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] By first fabricating metal mesh trenches on a large circular substrate using methods such as masking and plasma beam etching, and then filling the trenches with a metal layer and a protective layer through vacuum deposition, followed by machining to obtain an irregularly shaped large-area substrate, the uniformity of the metal mesh linewidth on its surface can be significantly improved. Through secondary exposure, development, stripping, and cleaning, edge ohmic connection metal lines with a width of less than 1 mm can be obtained, ensuring good conductivity of the metal mesh layer while also increasing the effective area of ​​the irregularly shaped large-area substrate. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the irregularly shaped large-area metal mesh optical window in the embodiment.

[0032] Figure 2 This is a basic process flow diagram of the metal mesh optical window in the embodiment.

[0033] Figure 3 This is a schematic diagram illustrating the processing of the irregularly shaped large-area metal mesh optical window shape in the embodiment.

[0034] Figure 4 This is a schematic diagram of the mechanical equipment used to process the edge groove structure in the embodiment.

[0035] Figure 5 This is a schematic diagram of the edge groove structure in the embodiment.

[0036] Figure 6 This is a microscopic schematic diagram of the irregularly shaped large-area metal mesh optical window in the embodiment.

[0037] Explanation of reference numerals in the attached drawings: 1. Irregularly shaped large-area substrate; 2. Mesh groove; 3. Metal mesh layer; 4. Protective layer; 5. Photoresist; 6. Circular large-area substrate; 7. Upper clamping plate; 8. Lower clamping plate; 9. Side clamping assembly; 10. Thin paper. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0039] Example 1: This application discloses a method for fabricating an irregularly shaped, large-area metal mesh optical window. (Refer to...) Figure 1-6 This includes the following steps:

[0040] S1: Create a large circular base 6 through initial machining.

[0041] This includes selecting one of the following materials: HK9L, quartz, microcrystalline, ZNS, ZNSE, Si, Ge, sapphire, and magnesium fluoride; selecting the material that can be deeply processed; and making a large-size circular substrate 6 by first mechanically cutting and then grinding and polishing.

[0042] S2: Clean the large circular substrate 6.

[0043] This includes cleaning a large circular substrate 6 using an ultrasonic cleaner, the method of which can be:

[0044] 1. Place the large circular substrate 6 in acetone and ultrasonically clean for 10 minutes to remove oil and organic residues;

[0045] 2. Transfer to ethanol and ultrasonically clean for 10 minutes to remove acetone residue;

[0046] 3. Place in deionized water and ultrasonically clean for 10 minutes to remove ethanol residue;

[0047] Among them, the ultrasonic frequency is 25-40kHz (25kHz is suitable for removing large particulate contaminants, and 40kHz is suitable for fine cleaning. It is necessary to avoid excessively high frequencies that may cause microstructure resonance), and the power density is 30-50W / L (excessive power may damage the coating or cause microcracks on the glass surface).

[0048] S3: Place the cleaned, large-area circular substrate 6 on a hot plate for pre-baking. After pre-baking, it needs to be placed at room temperature.

[0049] Place the large circular substrate 6 on a hot plate at 150-200°C and heat for 2-3 minutes to remove moisture. After heating, store it in a dry container as soon as possible.

[0050] S4: Coat the surface of the circular large-area substrate 6 with a photoresist of appropriate thickness 5.

[0051] Specifically, a spraying device is placed on the surface of a large circular substrate 6 to spray photoresist 5. The spraying device can be a homogenizer. The reason why the circular substrate can be homogenized more evenly is that its geometry perfectly matches the hydrodynamic characteristics of the homogenizer when it rotates, so that the photoresist 5 forms a symmetrical and stable distribution under the combined action of centrifugal force and surface tension.

[0052] S5: Create a reverse mask on a large circular base 6.

[0053] Through processes such as exposure, development, and cleaning, a mask with the opposite shape to the metal mesh is made on a large circular substrate 6; the shape of the metal mesh can be periodic or non-periodic, and the pattern can be selected according to the actual application.

[0054] Specifically:

[0055] S501, Exposure:

[0056] Mask design: The pattern on the mask = the metal grid lines themselves (transparent), and the remaining area is a chromium layer (opaque); in this way, on the positive resist, the transparent grid line area will undergo a photochemical reaction and dissolve during development; the opaque area of ​​the resist remains. At this time, the photoresist 5 opening area = metal grid lines → opposite to the grid shape (i.e., the opening corresponds to the lines). The corresponding exposure equipment can be a contact / proximity lithography machine or a projection lithography machine.

[0057] The exposure parameters are as follows:

[0058] Exposure wavelength: g line (436nm), h line (405nm) or i line (365nm);

[0059] Exposure dosage: 80~150mJ / cm² (the specific dosage needs to be optimized through experiments to ensure clear lines and no residue).

[0060] Alignment accuracy: For large-area substrates, alignment marks pre-made on the substrate are required to achieve multi-layer overlay (if necessary).

[0061] S502, Development:

[0062] After exposure, the substrate is completely immersed in the developer and gently shaken. Once the development endpoint is reached, immediately rinse with deionized water for 30 seconds to terminate the reaction. The photoresist 5 in the exposed area (grid lines) is completely dissolved, exposing the substrate. The photoresist in the unexposed area is retained.

[0063] The developer can be a TMAH (tetramethylammonium hydroxide) based developer (such as AZ300MIF, concentration 2.38%); use static immersion or spraying method, and set the temperature of the developer to 23±0.5℃ (temperature fluctuations affect linewidth); time: 40~90s (the specific time depends on the photoresist thickness and exposure dose, and is determined by the breakpoint method).

[0064] S502. Cleaning and Drying:

[0065] Rinse the substrate surface thoroughly with deionized water to remove residual developer and dissolved adhesive; dry with high-purity nitrogen or use a spin dryer (800-1000 rpm, 30 s).

[0066] S6: Etching metal mesh groove 2.

[0067] The surface of the optical substrate with the reverse mask is etched using a plasma beam to form a grid groove 2 with the same shape as the metal grid; the width and depth of the grid groove 2 should be determined according to the specific parameter requirements of the metal grid.

[0068] S7: Metal mesh layer 3 is plated.

[0069] A metal mesh layer 3 is deposited on the surface of a large circular substrate 6 with metal mesh grooves 2 using a vacuum deposition method. The material of the thin film can be one or more of the following metal materials: Ni (nickel), Cr (cadmium), Cu (copper), Ag (silver), Au (copper), Al (aluminum), etc., or transparent conductive oxides such as ITO (indium tin oxide), or a multilayer conductive film composed of a metal thin film and a transparent conductive oxide. The thickness h of the metal mesh layer 3 is less than the depth H of the mesh grooves.

[0070] S8: Protective layer 4 is plated.

[0071] Using vacuum coating, a protective layer 4 is deposited on the surface of the metal mesh layer 3. The material of the protective layer 4 is the same as or similar to that of the optical substrate material. The difference between the thickness of the protective layer 4 and the depth of the mesh groove 2 and the thickness of the metal mesh layer 3 is approximately equal to d≈Hh. After processing, a preliminary optical window is formed.

[0072] S9: The irregular large-area substrate 1 is produced by further machining.

[0073] The circular preliminary optical window after the metal mesh layer 3 and the protective layer 4 is placed in the processing center for laser processing and side polishing to finally form the required irregular large area substrate 1. At this time, the metal mesh in the irregular large area substrate 1 is uniformly distributed.

[0074] S901: Place the circular preliminary light window into the preset position and fix it to the laser processing equipment using a fixing component. The laser processing equipment can be a laser cutting machine, which cuts the circular preliminary light window.

[0075] Specifically, the fixing assembly is a combination system consisting of multi-point vacuum suction cups, elastic pressure claws, or low-temperature dispensing devices. For large-sized or ultra-thin circular preliminary light windows, conventional mechanical clamping can easily cause stress deformation or edge cracking. Therefore, a zoned vacuum adsorption platform is often used, combined with a soft sealing ring to apply pressure evenly, while avoiding obstruction of the cutting path. For spherical or aspherical circular preliminary light windows with large curvature, contour-following pressure blocks or magnetic flexible membranes are required for fixation. The fixing assembly also needs to have real-time pressure monitoring capabilities to prevent displacement or loosening caused by vibration during processing.

[0076] Depending on the material of the optical window and the processing requirements, different wavelengths of lasers can be selected: for example, CO2 lasers are suitable for cutting infrared materials such as quartz, glass, and ZnSe; ultraviolet nanosecond or femtosecond lasers are suitable for high-hardness and brittle materials such as sapphire and magnesium fluoride, which can significantly reduce the heat-affected zone; the equipment needs to be equipped with a rotary table or cross motion axes to achieve interpolation motion of circular trajectories; for irregular large-area substrates, a five-axis linkage laser cutting machine is required to ensure the perpendicularity of the edges.

[0077] 902: Polish the cut optical window. Before polishing, use a soft brush or polyurethane abrasive disc to remove obvious slag and burrs from the cut edge at low speed. Then place the optical window in a multi-frequency ultrasonic cleaning tank and use a neutral cleaning agent (pH≈8) with deionized water to remove dust, coolant residue and organic contaminants adhering to the surface. Use a non-contact 3D profilometer or high-magnification stereomicroscope to measure the chipping size of the cut edge (allowable chipping width <50μm) and the thickness of the heat-affected layer (typical value 50~200μm) to determine the subsequent polishing allowance, and then begin the polishing process.

[0078] S10: Strip and clean the non-grid area.

[0079] The irregular large-area substrate 1 after laser processing and side polishing is subjected to surface stripping and cleaning. The stripping method can be ultrasonic immersion in stripping solution. It can be first coarsely cleaned with 40kHz, and then finely cleaned with 80kHz or higher frequency to balance cleanliness and surface protection.

[0080] S11: Apply adhesive to protect the core area.

[0081] The large-area irregularly shaped substrate 1, cleaned in S10, is placed into a photoresist spraying device, and a certain thickness of photoresist 5 is sprayed onto its surface. The thickness of the photoresist 5 is usually between 2 micrometers and 10 micrometers. The spraying method can be either spraying or spin coating. Spraying is used on both flat and uneven surfaces, and the thickness accuracy is usually ≤±10%. Spin coating is mainly used on flat surfaces, and the accuracy can reach ≤±3%.

[0082] S12: Photolithographic irregular edge.

[0083] By going through processes such as exposure, development, and cleaning again, an edge region is created on the substrate of the irregular large-area substrate 1, with the edge region width being less than 1mm.

[0084] S13: Plasma beam etching of irregular edges.

[0085] After the protective layer 4 is plated in S8, a thin paper 10 is attached to the non-grid surface of the large circular base 6. The edge of the thin paper 10 is cut so that it is the same size as the large circular base 6 and the two are attached to each other. The center position of the thin paper 10 is found and marked.

[0086] The irregularly shaped large-area substrate 1 is clamped by a clamping assembly, which includes an upper clamping plate 7 and a lower clamping plate 8. The upper clamping plate 7 and the lower clamping plate 8 are symmetrically arranged and both can rotate, thereby driving the irregularly shaped large-area substrate 1 to rotate horizontally during subsequent processing. Before being clamped by the upper clamping plate 7 and the lower clamping plate 8, the irregularly shaped large-area substrate 1 is clamped and fed between the upper clamping plate 7 and the lower clamping plate 8 by a side clamping assembly 9. The side clamping plate can be a gripper. A positioning laser is provided at the rotation center of the lower clamping plate 8. First, the upper clamping plate 7 and the lower clamping plate 8 are separated. The irregularly shaped large-area substrate 1 is fed between the upper clamping plate 7 and the lower clamping plate 8 by the side clamping assembly 9. Then, the position is adjusted so that the positioning laser irradiates the marked position in the middle of the thin paper 10. At this time, the upper clamping plate 7 and the lower clamping plate 8 are engaged to clamp the irregularly shaped large-area substrate 1.

[0087] The plasma beam etching track is set up in the radial direction of a large circular metal mesh window. Then, using a second set of laser positioning, one edge groove structure is etched first. Then, by rotating the upper clamping plate 7 or the lower clamping plate 8, the next edge groove structure is processed. This process continues until the processing is completed. After that, the adjacent edge groove structures are connected to each other to form an edge groove structure that is connected to the internal metal mesh groove 2.

[0088] S14: Edge metal thin film plating.

[0089] A metal thin film is deposited on the surface of the optical substrate of the edge groove of the irregular large-area substrate 1 using vacuum deposition. The material of the thin film can be one or more of the following metals: Ni (nickel), Cr (cadmium), Cu (copper), Ag (silver), Au (copper), Al (aluminum), etc., or transparent conductive oxides such as ITO (indium tin oxide), or a multilayer conductive film composed of a metal thin film and a transparent conductive oxide. The metal thin film is the same as in step S7, which can achieve ohmic connection for all metal mesh structures.

[0090] S15: Edge protection film coating.

[0091] A protective film is deposited on the surface described in step S14 using a vacuum deposition method. The material of the protective film is the same as or similar to that of the optical substrate material, and the film thickness is the same as that in S8.

[0092] S16: Peel and clean the internal core area to form a large-area irregularly shaped metal mesh light window.

[0093] Example 2: This application discloses an irregularly shaped large-area metal mesh optical window, referring to... Figure 1-3It includes an irregularly shaped large-area substrate 1, a mesh groove 2, a metal mesh layer 3, and a protective layer 4. The mesh groove 2 is a microstructure groove below the surface of the irregularly shaped large-area substrate 1. The metal mesh layer 3 is filled in the mesh groove 2, and the protective layer 4 is attached to the upper surface of the irregularly shaped large-area substrate 1.

[0094] The irregularly shaped large-area substrate 1 has a polygonal irregular shape, a thickness greater than 3 mm, and a maximum diagonal length greater than 10 inches. The irregularly shaped large-area substrate 1 is made of one of the following materials: HK9L, quartz, microcrystalline, ZNS, ZNSE, Si, Ge, sapphire, and magnesium fluoride. The mesh groove 2 is a mesh-like microstructure formed below the surface of the irregularly shaped large-area substrate 1, and the sidewall verticality error of the microstructure is less than ±5%. The projected shape of the metal mesh groove 2 is one or more of the following: a periodically arranged square array, a circular array, a honeycomb array, and an irregular mesh pattern. The metal mesh layer 3 includes multiple periodically arranged mesh units, and each mesh unit is interconnected without being separated. The arrangement period of the mesh units in the metal mesh layer 3 is 100–1000 micrometers, the linewidth is 1–10 micrometers, and the ratio of the linewidth to the arrangement period is less than 0.1. The uniformity error of the metal mesh linewidth is within ±5%.

[0095] Employing a large-area substrate with an irregular polygonal shape, a thickness exceeding 3mm, and a diagonal exceeding 10 inches, this design meets the assembly and usage requirements of large-diameter, non-standard geometric contour optical windows, making it particularly suitable for aerospace optoelectronic pods, shipborne optoelectronic tracking systems, and large vehicle-mounted optoelectronic equipment. The greater thickness enhances the substrate's mechanical strength and thermal shock resistance, reducing the risk of deformation and breakage in harsh environments, thus ensuring the structural stability and long-term reliability of the metal mesh layer 3. Matching optical materials can be selected based on specific applications: for example, sapphire and quartz are suitable for high-hardness, scratch-resistant windows; ZnS / ZnSe is suitable for infrared thermal imaging; Si / Ge is suitable for long-wave infrared; and magnesium fluoride is suitable for ultraviolet to mid-infrared. Appropriate selection of substrate materials ensures high light transmittance while also considering thermal expansion matching, chemical stability, and processing performance, thereby improving the environmental adaptability and optical efficiency of the mesh window.

[0096] The high-precision (sidewall verticality error ≤ ±5%) microstructure of the grid groove 2 ensures that the subsequently filled metal grid layer 3 has a rectangular or near-rectangular cross-sectional shape, thereby significantly reducing the additional resistance changes and electromagnetic wave reflection losses caused by sidewall tilting during electromagnetic shielding. Simultaneously, the vertical sidewalls help maintain the set linewidth and periodic parameters, avoiding the deterioration of optical diffraction effects and ensuring the consistency of the window's transmittance and electromagnetic shielding effectiveness in the target wavelength band (such as infrared and visible light). Different projection shapes can be optimized for different electromagnetic interference frequency bands and incident angles: square arrays provide balanced shielding performance across a wide frequency range; circular arrays are suitable for circularly polarized wave interference environments; cellular arrays can achieve higher aperture ratios (thus improving optical transmittance) under equal linewidth conditions; irregular mesh patterns can avoid moiré fringes or coherent noise caused by periodic structures, making them particularly suitable for focal plane array detection systems. By flexibly selecting or combining these shapes, multiple targets requiring high transmittance, low stray light, and strong electromagnetic shielding can be addressed.

[0097] All grid cells form a continuous conductive network, constituting a complete low-impedance conductive path, avoiding local current interruptions or antenna effects caused by cell open circuits. This continuous structure effectively suppresses the circulation blockage of induced currents, achieving uniform and efficient electromagnetic shielding across the entire window area (e.g., shielding effectiveness exceeding 30dB in the 1–18 GHz range), while avoiding scattering hotspots caused by broken lines, maintaining the cleanliness of infrared or visible light images. This parameter range represents the optimal balance between optical transmittance and electromagnetic shielding effectiveness: a period less than 100 μm easily leads to enhanced diffraction effects, while a period greater than 1000 μm results in decreased shielding effectiveness; a linewidth of 1–10 μm ensures sufficiently low resistivity (typically using Cu, Au, or Ag materials), while a linewidth / period ratio of less than 0.1 ensures that the metal blocking area is less than 10%, thereby maintaining optical transmittance above 90% (for mid-wave infrared) or higher (for long-wave infrared). This design effectively avoids the severe energy loss of traditional wide-line-width grids.

[0098] Strict linewidth uniformity control (within ±5%) ensures that each grid cell has nearly identical resistivity and optical diffraction characteristics, thereby eliminating parasitic capacitance differences and diffraction efficiency inhomogeneities caused by local linewidth deviations. This directly translates into a highly consistent transmission wavefront and stable electromagnetic shielding effectiveness across the entire window (e.g., shielding effectiveness fluctuations less than ±1.5 dB), avoiding "grid shadows" or "bright and dark stripes" artifacts on the imaging system, making it particularly suitable for optical systems of high-resolution, large-area detectors.

[0099] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for fabricating an irregularly shaped, large-area metal mesh optical window, characterized in that, include: A large circular base (6) is made by means of initial machining, wherein the initial machining includes one or more of the following processes: mechanical cutting, grinding and polishing. Photoresist (5) is coated on the surface of a large circular substrate (6), and a mask with the opposite shape to the preset metal mesh is made on the large circular substrate (6). Etch a metal mesh groove (2); deposit a metal mesh layer (3) on the optical substrate surface of the metal mesh groove (2), and deposit a protective layer (4) on the surface of the metal mesh layer (3) to obtain a preliminary optical window; The irregular large-area substrate is made by re-machining, the re-machining including cutting and polishing processes; The non-grid area was stripped and cleaned, and then a layer of photoresist was sprayed onto its surface (5); An edge mesh trench is formed by etching the edge of the irregularly shaped large-area substrate (1). An edge metal mesh layer (3) is deposited on the optical substrate surface of the edge mesh trench; and an edge protective layer (4) is deposited on its surface; and The core area was peeled off and cleaned to form a large, irregularly shaped base.

2. The method for manufacturing an irregularly shaped large-area metal mesh optical window according to claim 1, characterized in that, The plating of the metal mesh layer (3) includes: A metal mesh layer (3) is deposited on the surface of an optical substrate with engraved metal mesh grooves (2) using a vacuum deposition method. The material of the metal mesh layer (3) includes one or more of the following metal materials: Ni (nickel), Cr (cadmium), Cu (copper), Ag (silver), Au (copper), and Al (aluminum), or a transparent conductive oxide, or a multilayer conductive film composed of a metal thin film and a transparent conductive oxide.

3. The method for manufacturing an irregularly shaped large-area metal mesh optical window according to claim 1, characterized in that: Before forming edge grid grooves on the metal grid irregular edge of the etched large-area substrate (1), an edge region is made on the optical substrate by one or more of the following methods: exposure, development, and cleaning. The width of the edge region is less than 1 mm.

4. The method for manufacturing an irregularly shaped large-area metal mesh optical window according to claim 1, characterized in that: Before coating the surface of the circular large-area substrate (6) or the irregular large-area substrate (1) with photoresist (5), the circular large-area substrate (6) or the irregular large-area substrate (1) is cleaned with an ultrasonic cleaner. The cleaned circular large-area substrate (6) or the irregular large-area substrate (1) is placed on a hot plate for pre-baking to remove most of the moisture adsorbed on the substrate surface. After pre-baking, it is placed at room temperature.

5. The method for manufacturing an irregularly shaped large-area metal mesh optical window according to claim 1, characterized in that: The edge metal mesh layer (3) is made of the same material as the metal mesh layer (3).

6. The method for fabricating an irregularly shaped large-area metal mesh optical window according to claim 1, Its features are: The method of stripping and cleaning the non-grid area, and then spraying a layer of photoresist (5) onto its surface includes: A photoresist of a predetermined thickness was applied by placing a glue spraying device at the metal mesh window (5).

7. An irregularly shaped large-area metal mesh optical window, prepared by the method described in any one of claims 1-6, characterized in that: It includes an irregular large-area substrate (1), a mesh groove (2), a metal mesh layer (3) and a protective layer (4). The mesh groove (2) is a microstructure groove under the surface of the irregular large-area substrate (1). The metal mesh layer (3) is filled in the mesh groove (2). The protective layer (4) is attached to the upper surface of the irregular large-area substrate (1).

8. The irregularly shaped large-area metal mesh optical window according to claim 7, characterized in that: The irregular large-area base (1) is polygonal and irregular in shape, with a thickness greater than 3mm and a maximum diagonal length greater than 10 inches.

9. The irregularly shaped large-area metal mesh optical window according to claim 7, characterized in that: The irregular large-area substrate (1) is made of one of the following materials: HK9L, quartz, microcrystalline, ZNS, ZNSE, Si, Ge, sapphire, or magnesium fluoride.

10. The irregularly shaped large-area metal mesh optical window according to claim 7, characterized in that: The projected shape of the metal mesh groove (2) is one or more of the following: a periodically arranged square array, a circular array, a honeycomb array, and an irregular mesh pattern; the metal mesh layer (3) includes a plurality of periodically arranged mesh units, and each mesh unit is continuously connected to the others.

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