Method and device for preparing large-area microstructure with non-deployable curved surface based on paper-cut method

Abstract

The invention discloses a method and a device for preparing a large-area microstructure with a non-deployable curved surface based on a paper-cut method. The method comprises the following steps: S1, forming a photoetching dry film layer on the non-deployable curved surface of a workpiece; s2, dividing the non-deployable curved surface into a plurality of deployable small-area infinitesimal elements approximate to a plane through digital modeling analysis; expanding the divided non-expandable curved surface to obtain an approximately two-dimensional shear pattern; s3, cutting the flexible photoetching mask plate according to the shearing pattern, and attaching the cut flexible photoetching mask plate to the surface of the photoetching dry film layer; through exposure and development, required micro-pattern hollows are formed on the photoetching dry film layer; s4, a working solution is introduced between the workpiece and the anode, voltage is applied to the two electrodes, and electrochemical deposition is carried out in the micro-pattern hollows; and S5, removing the photoetching dry film layer, and preparing a large-area array structure or a micro-nano pattern on the non-expandable curved surface. The invention solves the problems of low photoetching precision, difficult realization of micro-structure processing, high cost and the like on the non-deployable curved surface.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical additive manufacturing, and in particular to a method and device for preparing a large-area microstructure of a non-expandable curved surface based on a paper-kirigami method. Background Art

[0002] With the rapid development of the automotive industry, aerospace, national defense and other technical fields, the requirements for anti-corrosion, waterproof and anti-icing performance on curved surfaces are getting higher and higher. Traditional planar lithography processes have great limitations on applications on curved surfaces. Curved optical components or devices usually have complex curved shapes, which leads to unstable processes and difficulty in achieving high-quality graphic transfer. The development of curved microarray processing has made greater progress in overcoming the defects of traditional planar microarray processing, but there are still major challenges.

[0003] In order to solve these problems, many three-dimensional curved surface microstructure manufacturing technologies have emerged, including 3D printing, laser direct writing, and curved surface transfer technology. However, the types of materials that can be used for three-dimensional curved surface printing are relatively limited and the resolution of 3D printing is limited. Compared with traditional flat printing technology, laser direct writing technology usually takes longer to complete printing, especially for complex curved surface structures. Curved transfer technology is suitable for some special-shaped surfaces, but may not be suitable for very complex or special-shaped surfaces.

[0004] In 2020, a Chinese patent application numbered CN202010554663.3 disclosed a method for cutting a thin film structure. The invention discloses a method for cutting a thin film structure, including selecting a spatial membrane sheet, a cutting edge of which has been determined in advance, dividing the spatial membrane sheet into regions, and using geometric principles to ensure that the spatial membrane can be unfolded into a flat membrane sheet without error. This method is applied to the unfolding of large-size films, and the cutting shape is single. For the segmentation of mask sheets with higher hardness, it is difficult to effectively eliminate the stress changes caused by the mask sheet lamination on a complex variable curvature surface.

[0005] In 2018, a Chinese patent with application number CN201810456005.3 disclosed a curved surface lithography process based on transparent flexible thin film materials, including the following steps: unfolding the target curved surface pattern along a plane, making the planarized pattern on a planar photolithography mask or hard mask; selecting a flexible thin film material; processing it with a photolithography mask, or processing the flexible thin film material with a hard mask to obtain a flexible substrate with a complete non-transparent pattern on the surface; applying glue on the curved surface to be photolithography, and attaching the flexible substrate tightly and seamlessly to the curved surface to be photolithography, and after exposure and development, curved surface lithography can be achieved. This method is mainly aimed at lithography of expandable curved surfaces, but it is difficult to overcome the curvature problem of non-expandable curved surfaces, and it is difficult to achieve mask lithography on non-expandable curved surfaces.

[0006] In 2015, a Chinese patent with application number CN201510037978.X disclosed a flexible, stretchable, deformable curved surface photolithography template and a photolithography method and device. A stretchable flexible photolithography mask and a flexible ultraviolet light-emitting diode (LED) panel are made as light sources for exposure, and the flexible stretchable template is tightly attached to a substrate coated with photoresist under the action of controllable stress, and the flexible LED panel is tightly attached to the flexible template before photolithography. This method can realize photolithography on some complex curved surfaces, but because the flexible stretchable mask plate used will cause a certain amount of deformation of the structure on the mask plate due to the tensile force during the bonding process, reducing the photolithography accuracy.

[0007] In 2019, a Chinese patent with application number CN201911417378.0 disclosed a curved surface lithography method using DMD and liquid crystal modulation. DMD is used as a digital grayscale mask modulator to modulate the amplitude of the incident light, and liquid crystal is added as a phase modulator to modulate the phase of the incident light, thereby converting the incident plane wave into a beam of a specific wavefront, and then passing through the projection lens, and finally imaging on the curved photoresist substrate, thereby realizing curved surface lithography. Since the DMD micromirror is based on digital control, this method may cause uneven exposure intensity in each area, thereby affecting the quality and consistency of the final pattern.

[0008] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgement or any form of suggestion that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0009] Purpose of the invention: The technical problem to be solved by the present invention is to address the deficiencies in the prior art and to provide a method and device for preparing large-area microstructures on non-expandable curved surfaces based on the paper-kirigami method, which can realize photolithography and electrochemical deposition of large-area microstructures on non-expandable curved surfaces and have higher microstructure accuracy.

[0010] In order to solve the above technical problems, the first aspect of the present invention discloses a method for preparing a large-area microstructure of a non-expandable curved surface based on a paper-kirigami method, which comprises:

[0011] S1, forming a photolithography dry film layer on the non-developable curved surface of the workpiece;

[0012] S2. Divide the non-developable surface into a plurality of developable small-area microelements that are approximately planes through digital modeling analysis, and determine the number of divisions within a unit area according to the structure of the non-developable surface; unfold the divided non-developable surface to obtain an approximately two-dimensional shearing pattern;

[0013] S3, cutting the flexible photolithography mask plate according to the shearing pattern, and attaching it to the surface of the photolithography dry film layer on the side away from the non-expandable curved surface after cutting; forming the desired micro-pattern hollowing on the photolithography dry film layer through exposure and development;

[0014] S4, introducing a working fluid between the workpiece and the anode, and applying a voltage to the workpiece as a cathode and the anode to perform electrochemical deposition in the micro-pattern hollowing;

[0015] S5, removing the photolithography dry film layer, and preparing a large-area array structure or a micro-nano pattern on the non-developable curved surface.

[0016] Specifically, the S1 includes:

[0017] The non-expandable curved surface of the workpiece is coated with a photolithography dry film by a stretching and hot pressing method. The photolithography dry film is stretched, and the stretching force in each direction is kept the same. During the stretching process, the photolithography dry film undergoes elastic deformation so that the photolithography dry film can adapt to the contour of the non-expandable curved surface of the workpiece. After the photolithography dry film completely covers the non-expandable curved surface of the workpiece, it is hot pressed to obtain a photolithography dry film layer;

[0018] Alternatively, the photoresist is uniformly coated on the non-developable curved surface of the workpiece by spin coating, and then the workpiece is placed on a hot plate for pre-baking.

[0019] Specifically, the step of forming the desired micro-pattern hollowing out on the photoresist dry film layer by exposure and development includes: curing the area of ​​the photoresist dry film layer outside the desired micro-pattern by photoresist exposure; after the exposure is completed, removing the unexposed area in the photoresist dry film layer by photoresist development.

[0020] Preferably, the non-developable surface is a rotationally symmetric surface; in S4, the workpiece and the anode are in a relative rotation state. Specifically, in order to achieve the relative rotation state between the workpiece and the anode, the anode can be set to be stationary, and the workpiece as the cathode can be driven by a servo motor to perform self-rotation motion, so as to achieve uniform deposition of all parts of the non-developable surface; or, the workpiece as the cathode can be set to be stationary, and the anode can be driven by a rotating tray to perform a circular rotation motion around the cathode workpiece, so as to achieve uniform deposition of all parts of the non-developable surface.

[0021] Specifically, in S2, the non-expandable surface is divided into a plurality of expandable small-area microelements that are approximately planes, and different structural division densities are set according to different curvatures of different regions in the non-expandable surface; a higher structural division density is set in a high curvature region, and a lower structural division density is set in a low curvature region.

[0022] In this embodiment, different structural division densities are designed to increase the division density of the high curvature region, so as to ensure that the alignment gap is smaller than the critical gap that affects the photolithography quality.

[0023] Specifically, the shape of the small-area element is determined according to the different shapes and sizes of the non-developable surface; the shape of the small-area element is any one of a ring, a sector and a plane polygon or a combination of several of them.

[0024] Specifically, the flexible photolithography mask plate is a bendable and non-stretchable mask plate, selected from one of a PET mask plate, a PDMS mask plate, a PI mask plate and an organic film mask plate; the opaque pattern of the flexible photolithography mask plate is divided into a linear structure pattern, a dot structure pattern and a composite structure pattern according to its use.

[0025] Specifically, the anode is designed according to the shape and size of the non-developable curved surface, and the anode is designed as a linear anode, a sheet anode with the same curvature as the workpiece, or a fully wrapped anode;

[0026] Among them, the linear anode and the sheet anode with the same curvature as the workpiece both maintain the same curvature as the non-developable surface, and perform cyclic reciprocating motion around the non-developable surface of the workpiece, causing an electron transfer reaction between the anode and the cathode, and electrochemical reduction occurs on the surface of the curved surface, thereby realizing large-area structural deposition on the curved surface.

[0027] The fully wrapped anode has the same shape as the workpiece, and can completely cover the non-developable curved surface of the workpiece, and reserve a processing gap between the anode and the non-developable curved surface of the workpiece during covering.

[0028] In the present application, two curved surfaces maintaining the same curvature means that the distance between the two curved surfaces is the same at any point.

[0029] Specifically, in S4, when the anode is the linear anode or the workpiece-same-curvature anode, the workpiece and the anode are arranged to be completely immersed in the working fluid; when the anode is the fully-enclosed anode, the working fluid is supplied in the form of flushing liquid to continuously flush the processing gap between the workpiece and the anode.

[0030] Specifically, in order to avoid low photolithography precision due to different incident angles of different parts of the curved surface, the exposure adopts a digitally controlled multi-point light source or a linear light source;

[0031] The digitally controlled multi-point light source includes a plurality of point light sources, which are evenly distributed in all directions of the non-developable surface and can illuminate the non-developable surface at the same time, so as to ensure that each part of the non-developable surface receives the same illumination parameters;

[0032] The linear light source can emit linear light with the same curvature as the non-developable surface. When the workpiece rotates, the linear light emitted by the linear light source passes over the non-developable surface to eliminate light scattering.

[0033] Specifically, the S5 includes: soaking the workpiece after the electrodeposition in an organic solvent to remove the photolithography dry film layer on the surface of the workpiece.

[0034] Specifically, the bonding step includes: using a gap filling material to fill the gap between the flexible photolithography mask and the non-expandable curved surface of the workpiece; the gap filling material is selected from one or a combination of two or more of PDMS, UV glue and extracellular matrix gel.

[0035] The second aspect of the present invention discloses a device for implementing the above-mentioned paper-kirigami-based non-expandable curved large-area microstructure preparation method, which includes a CNC machine tool, a deposition tank, a frame, a liftable robotic arm, a mask lithography system, an electrochemical deposition processing system and a power supply system.

[0036] Wherein, the CNC machine tool comprises a movable CNC workbench; a deposition tank is fixedly installed on the CNC workbench, and a workpiece fixing fixture for fixing the workpiece is arranged in the deposition tank;

[0037] The frame is liftably connected to the top of the machine tool base through a liftable mechanical arm, and the mask lithography system and the electrochemical deposition processing system are both installed on the frame and are both arranged on the moving path of the CNC workbench;

[0038] The mask photolithography system comprises a stretching mechanism for uniformly clamping and stretching a photolithography dry film from which a thick protective film has been removed, a movable hot pressing mold, a heating oil cylinder, a pressure gauge, a CNC multi-point light source and a light source adjustment device; the movable hot pressing mold is connected to the telescopic end of the heating oil cylinder and is kept above the photolithography dry film after being heated; when the CNC workbench moves to make the workpiece and the movable hot pressing mold face each other up and down and the heating oil cylinder heats the movable hot pressing mold to the hot pressing target temperature, the heating oil cylinder drives the movable hot pressing mold to move downward until the photolithography dry film is hot-pressed and attached to the non-expandable curved surface of the workpiece; the CNC multi-point light source is used to provide light with the same illumination parameters to each part of the non-expandable curved surface of the workpiece;

[0039] The electrochemical deposition processing system includes a self-rotating platform, an anode clamp for fixing the anode, a temperature detection device and a heating device; the self-rotating platform is installed on the liftable mechanical arm; the anode clamp is fixedly connected to the bottom of the self-rotating platform; the heating device is used to heat the working fluid in the deposition tank to a second target temperature; the temperature detection device is used to monitor the temperature of the working fluid in the deposition tank in real time;

[0040] The power supply system comprises a first power supply and a high-frequency bidirectional pulse current power supply, wherein the first power supply is used to supply power to the mask lithography system; the positive electrode of the high-frequency bidirectional pulse current power supply is connected to the anode, and the negative electrode is connected to the workpiece, and a closed circuit is realized when a working fluid is introduced between the workpiece and the anode;

[0041] The device is configured to, after the mask lithography of the workpiece is completed, control the CNC machine tool to move the CNC worktable to drive the workpiece to move synchronously to the bottom of the self-rotating platform and to fully immerse the anode in the working fluid in the deposition tank while leaving a processing gap between the anode and the workpiece; the self-rotating platform can drive the anode to perform a revolving circular motion around the workpiece through the anode clamp, thereby realizing the preparation of large-area microstructures of non-expandable curved surfaces.

[0042] Beneficial effects:

[0043] 1) In the method for preparing large-area microstructures on non-expandable curved surfaces based on the paper-kirigami method adopted by the present invention, the paper-kirigami method is applied to mask lithography for electrochemical preparation of surface microstructure arrays or micro-nano patterns, the curved surface is computationally divided into small-area micro-elements, and the mask is cut to the shape of the micro-unit area for fitting lithography. Through the method of the present invention, lithography of curved microstructures with different curvatures can be achieved, overcoming the problem of low lithography accuracy caused by different curvatures of the curved surface and the mask.

[0044] 2) In the paper-cutting-based non-expandable curved surface large-area microstructure preparation method adopted by the present invention, after the surface is divided and unfolded using mathematical modeling, the shape of the lithographic structure can be compensated, thereby overcoming the problem of deformation of the curved surface lithographic structure caused by different curvatures.

[0045] 3) In the device for preparing large-area microstructures of non-expandable curved surfaces based on the paper-kirigami method adopted by the present invention, the deposition tank is clamped on the CNC workbench during electrochemical deposition, and the CNC workbench can be moved up, down, left and right by a driving mechanism such as a motor to drive a screw rod. After the coating lithography area is completed, the CNC workbench can be directly moved to the deposition area for electro-deposition, thereby reducing downtime and improving production efficiency.

[0046] 4) In the device for preparing a large-area microstructure on a non-expandable curved surface based on the paper-kirigami method, the present invention adopts a stretching and hot pressing method to coat the surface of the curved workpiece. Compared with the traditional photolithography dry film mask, the stretching and hot pressing method avoids the wrinkle problem caused by the inconsistent curvature of the photolithography dry film and the curved workpiece during bonding.

[0047] 5) In the paper-kirigami-based non-expandable curved surface large-area microstructure preparation method adopted by the present invention, multi-point rotary lithography or linear lithography is used to compensate for the different incident angles in different areas caused by the curvature of the workpiece.

[0048] 6) In the method for preparing a large-area microstructure of an undevelopable curved surface based on the paper-cutting method adopted by the present invention, the curved surface is divided into any one or a combination of rings, sectors and planar polygons according to the different shapes and sizes of the undevelopable curved surface. Units of different shapes are selected according to different curvatures to achieve the best fit, and different division shapes can effectively reduce the internal stress caused by the elastic deformation of the mask.

[0049] 7) The electrochemical working fluid replenishment method in the paper-kirigami-based non-expandable curved surface large-area microstructure preparation method adopted by the present invention adopts a complete immersion method when a linear anode or an anode with the same curvature as the workpiece is used to ensure that there is always enough ion concentration near the electrode. When a fully wrapped anode is used, a flushing method is used to ensure that there is always enough ion concentration near the electrode, which is also helpful for the discharge of the processed product.

[0050] 8) The paper-kirigami-based method for preparing large-area microstructures on non-expandable curved surfaces adopted in the present invention can realize microarray and patterned preparation of the outer and inner surfaces of the curved surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0052] Figure 1 It is a structural schematic diagram of an embodiment of a device for preparing a large-area microstructure of a non-expandable curved surface based on a paper-kirigami method provided in the embodiments of the present invention;

[0053] Figure 2 It is a typical schematic diagram of the unfolding of the non-expandable curved surface paper-kirigami method in the method for preparing a large-area microstructure of a non-expandable curved surface based on the paper-kirigami method provided in the embodiments of the present invention;

[0054] Figure 3 It is a schematic diagram of the processing flow of a method for preparing a large-area microstructure of a non-expandable curved surface based on a paper-kirigami method provided in the embodiments of the present invention;

[0055] FIG. 4( a ) is a schematic diagram of a linear anode and workpiece deposition process provided in some embodiments of the present invention;

[0056] FIG4( b ) is a schematic diagram of a workpiece-like curvature sheet anode and a workpiece deposition process provided in some embodiments of the present invention;

[0057] FIG4( c ) is a schematic diagram of a fully wrapped anode and workpiece deposition process provided in some embodiments of the present invention;

[0058] Figure 5 It is a schematic diagram of the electrochemical deposition principle of a method for preparing a large-area microstructure of a non-expandable curved surface based on a paper-kirigami method provided in the embodiments of the present invention;

[0059] FIG6( a ) is a cylindrical microarray structure prepared on a spherical surface by using the non-expandable curved surface large-area microstructure preparation method based on the paper-kirigami method provided in the embodiments of the present invention;

[0060] FIG6( b ) is a micro-nano pattern prepared on the outer surface of a spherical surface by using the non-expandable curved surface large-area microstructure preparation method based on the paper-kirigami method provided in the embodiments of the present invention;

[0061] FIG6( c ) is a linear array structure prepared on the surface of a curved pipe using the method for preparing a large-area microstructure on a non-expandable curved surface based on the paper-kirigami method provided in the embodiments of the present invention;

[0062] FIG6( d ) is a microarray structure prepared on a curved fan blade using the non-expandable curved surface large-area microstructure preparation method based on the paper-kirigami method provided in the embodiments of the present invention;

[0063] FIG6( e ) is a microarray pattern prepared on the inner surface of a pressure vessel using the method for preparing a large-area microstructure on a non-expandable curved surface based on the paper-kirigami method provided in the embodiments of the present invention.

[0064] Description of the accompanying drawings:

[0065] 1. Workpiece; 110. Undevelopable surface; 111. Small area microelement; 120. Shear pattern; 2. Photolithography dry film layer; 210. Micro pattern hollowing; 3. Flexible photolithography mask; 4. Anode; 401. Linear anode; 402. Sheet anode with same curvature as workpiece; 403. Fully wrapped anode; 4031. Through hole; 5. Working fluid 6. Photolithography dry film; 7. CNC multi-point light source; 8. CNC machine tool; 9. Deposition tank; 10. Rack; 11. Liftable robotic arm; 121. First power supply; 122. High-frequency bidirectional pulse current power supply; 13. CNC workbench; 9. Sedimentation tank; 14. Workpiece fixing fixture; 15. Stretching mechanism; 16. Movable hot pressing mold; 17. Heating cylinder; 18. Pressure gauge; 19. Light source adjustment device; 20. Self-rotating platform; 21. Anode fixture; 22. Temperature detection device; 23. Heating device; 24. Machine tool base; 25. Pull rod. DETAILED DESCRIPTION

[0066] Example 1

[0067] The curved surfaces of workpieces can generally be divided into developable surfaces and non-developable surfaces. Conventional developable surfaces are those that can be developed into planes without stretching, compression, wrinkles or tears, such as cylinders and cones. Non-developable surfaces are surfaces that cannot be developed into planes without deformation. The relevant prior art can only prepare microstructures on some conventional developable surfaces, but non-developable surfaces often have non-uniform curvature. During the masking process, the problem of fitting wrinkles is caused by the different curvatures of the photoresist film and the surface. During the photolithography process, due to the different curvatures of the mask plate and the surface, the fitting gap is too large, affecting the photolithography accuracy. During the electrodeposition process, the presence of curvature makes it difficult to effectively control the flow of the electrochemical working fluid, further exacerbating the unevenness of the deposition.

[0068] Based on this, this embodiment discloses a method for preparing a large-area microstructure on a non-expandable curved surface based on a paper-kirigami method, which can prepare a large-area array structure or micro-nano pattern on a non-expandable curved surface. The preparation method includes:

[0069] S1, forming a photolithography dry film layer 2 on the non-developable curved surface 110 of the workpiece 1;

[0070] S2. Dividing the non-developable curved surface 110 into a plurality of developable small-area micro-elements 111 that are approximately plane-like through digital modeling analysis, each of which is provided with a desired light-proof micro-pattern; the divided non-developable curved surface 110 can be approximately two-dimensionally developed to obtain an approximately two-dimensional shearing pattern 120;

[0071] S3, cutting the flat flexible photolithography mask plate 3 according to the shearing pattern 120, and attaching it to the surface of the photolithography dry film layer 2 on the side away from the non-developable curved surface 110 after cutting; forming the desired micro-pattern hollowing 210 on the photolithography dry film layer 2 through exposure and development;

[0072] S4, introducing the working fluid 5 between the workpiece and the anode 4, and applying voltage to the workpiece as the cathode and the anode 4, and performing electrochemical deposition in the micro-pattern hollow 210, during which the metal ions are transferred by electrons and reduced to metal atoms and deposited in the micro-pattern hollow 210;

[0073] S5. Remove the photolithography dry film layer, and prepare a large-area array structure or a micro-nano pattern on the non-developable curved surface 110.

[0074] Specifically, S1 includes:

[0075] The photolithography dry film 6 is stretched, and the stretching force in each direction is kept the same. During the stretching process, the photolithography dry film 6 undergoes elastic deformation, so that the photolithography dry film 6 can adapt to the contour of the non-expandable curved surface of the workpiece 1, and the photolithography dry film 6 is hot-pressed after it completely covers the non-expandable curved surface of the workpiece 1;

[0076] Alternatively, the photoresist is evenly coated on the non-developable curved surface of the workpiece 1 by spin coating, and then the workpiece is placed on a hot plate for pre-baking.

[0077] Specifically, mathematical modeling is used to segment the curved surface as a whole, and a photolithography pattern is drawn on the curved surface. After the modeling is completed, the curved surface is unfolded in a plane to obtain small-area microelements 111 of the mask cut size.

[0078] Specifically, a high-transmittance tape may be used to adhere the cut flexible photolithography mask plate 3 to a surface of the photolithography dry film layer 2 that is away from the non-developable curved surface 110 .

[0079] Specifically, the step of forming the desired micro-pattern hollowing 210 on the photolithography dry film layer 2 by exposure and development includes: curing the area of ​​the photolithography dry film layer 2 outside the desired micro-pattern by photoresist exposure; after the exposure is completed, removing the unexposed area in the photolithography dry film layer 2 by photoresist development.

[0080] Preferably, the non-developable surface 110 is a rotationally symmetric surface. In S4, the workpiece and the anode 4 are in a relative rotation state. Specifically, in order to achieve the relative rotation state between the workpiece and the anode 4, the anode 4 can be set to be stationary, and the workpiece 1 as the cathode can be driven by a servo motor to perform self-rotation motion to achieve uniform deposition of various parts of the non-developable surface; or, the workpiece as the cathode can be set to be stationary, and the anode 4 can be driven by a rotating tray to perform a circular rotation motion around the cathode workpiece to achieve uniform deposition of various parts of the non-developable surface.

[0081] Specifically, in S2, the non-expandable surface 110 is divided into a plurality of expandable small-area elements 111 that are approximately planes, and different structural division densities are set according to the different curvatures of different regions in the non-expandable surface 110; a higher structural division density is set in a high curvature region, and a lower structural division density is set in a low curvature region.

[0082] Specifically, the shape of the small-area element 111 is determined according to the different shapes and sizes of the non-developable surface 110 ; the shape of the small-area element 111 is any one of a ring, a sector and a plane polygon, or a combination of several of them.

[0083] Specifically, the flexible photolithography mask plate 3 is a bendable and non-stretchable mask plate, selected from a PET mask plate, a PDMS mask plate, a PI mask plate and an organic film mask plate; the opaque pattern of the flexible photolithography mask plate 3 is divided into a linear structure pattern, a dot structure pattern and a composite structure pattern according to the purpose. The opaque pattern of the flexible photolithography mask plate 3 corresponds to the required micro pattern.

[0084] Specifically, see Figure 4(a) to Figure 4(c) , the anode 4 is designed according to the shape and size of the non-developable curved surface 110, and the anode 4 is designed as a linear anode 401, a sheet anode 402 with the same curvature as the workpiece, or a fully wrapped anode 403;

[0085] Among them, FIG4(a) shows a schematic diagram of the deposition of the linear anode 401 and the workpiece, and the linear anode 401 can be made of a metal with high ductility, high toughness and high elasticity to ensure that the linear anode 401 can be bent into the same curvature as the curved surface. The linear anode 401 is easy to deform due to its linear structure and is more easily adapted to the curvature change on the curved surface. In S4, when the anode 4 is a linear anode 401, a complete immersion method is adopted, that is, the workpiece 1 and the anode 4 are completely immersed in the working liquid 5, and then the linear anode 401 is made to revolve around the non-expandable curved surface of the workpiece 1, so as to achieve uniform deposition on all parts of the curved surface.

[0086] FIG4(b) shows a schematic diagram of a workpiece with the same curvature sheet anode 402 and workpiece deposition. The workpiece 1 and the sheet anode 4 with the same curvature maintain the same curvature as the non-developable surface 110. The same curvature ensures that the distances from each part of the surface to the anode 4 are the same, reducing the problem of low deposition accuracy due to the divergence of electric field lines. In S4, when the anode 4 is a sheet anode 4 with the same curvature as the workpiece 1, the working fluid 5 is supplied in the form of flushing liquid to continuously flush the machining gap between the workpiece 1 and the anode 4.

[0087] FIG4(c) shows a schematic diagram of the fully wrapped anode 403 and the workpiece deposition. The fully wrapped anode 403 has the same large-size design as the workpiece 1, and can completely cover the non-expandable curved surface of the workpiece 1, and reserve a processing gap between the non-expandable curved surface of the workpiece 1 when covering. The fully wrapped anode 403 is suitable for the flushing method. The fully wrapped anode 403 has a through hole 4031 connected to a water pump to flush the processing gap between the anode 4 and the workpiece 1. The two rotate relative to each other to reduce the local uneven deposition caused by the opening, thereby achieving uniform deposition on all parts of the curved surface.

[0088] Specifically, in order to avoid low lithography accuracy due to different incident angles of different parts of the curved surface, the exposure adopts a digitally controlled multi-point light source 7 or a linear light source;

[0089] The numerically controlled multi-point light source 7 includes a plurality of point light sources, which are evenly distributed in all directions of the non-developable curved surface 110 and can illuminate the non-developable curved surface 110 at the same time, so as to ensure that each part of the non-developable curved surface 110 receives the same illumination parameters;

[0090] The linear light source can emit linear light with the same curvature as the non-developable curved surface 110. When the workpiece rotates, the linear light emitted by the linear light source passes over the non-developable curved surface 110 to eliminate light scattering.

[0091] In the present application, the lighting parameters include but are not limited to at least one of the following: lighting intensity, lighting time and lighting temperature.

[0092] Specifically, S5 includes: soaking the workpiece 1 after the electrodeposition is completed in an organic solvent to remove the photolithography dry film layer 2 on the surface of the workpiece.

[0093] Specifically, the bonding step includes: using gap filling material to fill the gap between the flexible photolithography mask plate 3 and the non-developable surface of the workpiece 1 to reduce the bonding gap problem caused by different curvatures; the gap filling material is selected from one or a combination of more than two of PDMS, UV glue and extracellular matrix gel.

[0094] Figure 3 A specific embodiment of the method for preparing a large-area microstructure on a non-expandable curved surface based on the paper-kirigami method of the present application is shown. Figure 3 In this specific embodiment, the photolithography dry film is attached to the workpiece surface in a stretched state, and the photolithography dry film itself is stretched and deformed to adapt to the curved surface to achieve wrinkle-free attachment. The divided photolithography mask is attached to the surface, and the surface is fully photolithographically processed using a numerically controlled multi-point light source 7, and the unexposed area is removed by development, thereby realizing mask photolithography of the array structure on the curved surface, and then placed in an electrochemical working solution 5 for spin deposition.

[0095] Figure 5 This is a schematic diagram of the principle of surface electrochemical deposition. The metal ions in the electrolyte gain electrons under the action of an external electric field and are reduced and deposited on the cathode surface.

[0096] Figure 6(a) to Figure 6(e) The typical results of preparing large-area microstructures on non-expandable curved surfaces based on the paper-kirigami method are shown. Among them, Figure 6(a) shows the preparation of a cylindrical microarray structure on the spherical outer surface of a workpiece, Figure 6(b) shows the preparation of a micro-nano pattern on the spherical outer surface of a workpiece, and Figure 6(c) shows the preparation of a linear array structure on the outer surface of a curved pipe workpiece. Figure 6(d) shows the preparation of a microarray structure on the surface of a curved fan blade workpiece, and Figure 6(e) shows the preparation of a microarray pattern on the inner surface of a pressure vessel.

[0097] In order to implement the method for preparing a large-area microstructure with a non-expandable curved surface based on the paper-kirigami method disclosed in this embodiment, this embodiment also provides a preparation device. Figure 1 is a schematic diagram of the structure of the preparation device provided in this embodiment, such as Figure 1 As shown, the preparation device includes a CNC machine tool 8, a deposition tank 9, a frame 10, a liftable mechanical arm 11, a mask lithography system, an electrochemical deposition processing system and a power supply system.

[0098] The CNC machine tool 8 includes a machine tool base 24 and a CNC workbench 13. The CNC workbench 13 can move up and down and left and right relative to the machine tool base 24. A deposition tank 9 is fixedly installed on the CNC workbench 13. A workpiece fixing fixture 14 for fixing the workpiece 1 is arranged in the deposition tank 9.

[0099] The frame 10 is escalably connected to the top of the machine tool base 24 through a escalable mechanical arm 11. The mask lithography system and the electrochemical deposition processing system are both installed on the frame 10 and are both arranged on the moving path of the CNC workbench 13.

[0100] The mask lithography system includes a stretching mechanism 15 for uniformly clamping and stretching a photolithography dry film 6 from which a thick protective film has been removed, a movable hot pressing mold 16, a heating cylinder 17, a pressure gauge 18, a CNC multi-point light source 7, and a light source adjustment device 19; the movable hot pressing mold 16 is connected to the telescopic end of the heating cylinder 17 through a pull rod 25 and is kept above the photolithography dry film 6 after being heated; when the CNC workbench 13 moves to a position where the workpiece 1 and the movable hot pressing mold 16 are opposite to each other up and down and the heating cylinder 17 heats the movable hot pressing mold 16 to a hot pressing target temperature, the heating cylinder 17 drives the movable hot pressing mold 16 to move downward until the photolithography dry film 6 is hot-pressed and attached to the non-expandable curved surface 110 of the workpiece 1; the CNC multi-point light source 7 is used to provide light with the same illumination parameters to each part of the non-expandable curved surface of the workpiece 1;

[0101] The electrochemical deposition processing system includes a self-rotating platform 20, an anode clamp 21 for fixing the anode 4, a temperature detection device 22 and a heating device 23; the self-rotating platform 20 is installed on a liftable mechanical arm; the anode clamp 21 is fixedly connected to the bottom of the self-rotating platform 20; the heating device 23 is used to heat the working fluid 5 in the deposition tank 9 to a second target temperature; the temperature detection device 22 is used to monitor the temperature of the working fluid 5 in the deposition tank 9 in real time;

[0102] The power supply system includes a first power supply 121 and a high-frequency bidirectional pulse current power supply 122. The first power supply 121 is used to supply power to the mask lithography system. The positive electrode of the high-frequency bidirectional pulse current power supply 122 is connected to the anode 4, and the negative electrode is connected to the workpiece 1. When the working fluid 5 is introduced between the workpiece 1 and the anode 4, a closed circuit is realized.

[0103] The device is configured to, after the mask lithography of the workpiece 1 is completed, control the CNC machine tool 8 to move the CNC worktable 13 to drive the workpiece 1 to move synchronously to the bottom of the self-rotating platform 20 and to make the anode 4 completely immersed in the working liquid 5 in the deposition tank 9 and retain a processing gap between the anode 4 and the workpiece 1; the self-rotating platform 20 can drive the anode 4 to perform a revolving circular motion around the workpiece 1 through the anode clamp 21, thereby realizing the electrochemical deposition of large-area microstructures on non-expandable curved surfaces.

[0104] Specifically, the numerical control table 13 is configured to be movable up and down and left and right relative to the machine tool base 24 .

[0105] Specifically, in the present application, the CNC machine tool 8 includes a moving mechanism for driving the CNC worktable 13 to move up and down and left and right relative to the machine tool base 24. The moving mechanism can adopt existing technology, such as a roller with a spiral structure driven by a motor, so it is not described in detail in the present application.

[0106] The following describes the method for using the preparation device of the present invention in the process of preparing a large-area microstructure with a non-developable curved surface.

[0107] First, the workpiece 1 is fixed in the deposition tank 9 by the workpiece fixing fixture 14. At this time, the movable hot pressing mold 16 connected to the telescopic end of the heating cylinder 17 is maintained above the photolithography dry film 6. The heating cylinder 17 is controlled to heat the movable hot pressing mold 16. The CNC workbench 13 is moved until the workpiece 1 and the movable hot pressing mold 16 are opposite to each other up and down. When the heating cylinder 17 heats the movable hot pressing mold 16 to the hot pressing target temperature, the heating cylinder 17 drives the movable hot pressing mold 16 to move downward until the photolithography dry film 6 is hot-pressed and attached to the non-expandable curved surface 110 of the workpiece 1. The heating cylinder 17 is controlled to drive the movable hot pressing mold 16 to move upward to separate from the photolithography dry film layer and leave space for exposure in the photolithography dry film layer. In this way, the photolithography dry film layer 2 is formed on the non-expandable curved surface of the workpiece.

[0108] Then, the flexible photolithography mask plate 3 cut according to the shear pattern 120 is attached to the surface of the photolithography dry film layer 2 on the side away from the non-developable curved surface 110. The numerically controlled multi-point light source 7 provides light with the same illumination parameters to each part of the non-developable curved surface of the workpiece 1, and these lights expose and cure the areas of the photolithography dry film layer 2 outside the desired micro pattern. After the exposure is completed, the unexposed areas in the photolithography dry film layer 2 are removed by photoresist development. In this way, the desired micro pattern hollowing 210 is formed on the photolithography dry film layer 2.

[0109] Then, the anode 4 is connected to the bottom of the anode fixture 21. After the mask lithography of the workpiece 1 is completed, the CNC machine tool 8 is controlled to move the CNC worktable 13 to drive the workpiece 1 to move synchronously to the bottom of the self-rotating platform 20, and then control the upward movement to ensure that a processing gap is reserved between the workpiece 1 and the anode 4. The electrochemical working fluid 5 is introduced into the deposition tank 9 to ensure that the workpiece 1 and the anode 4 are completely immersed in the working fluid 5. The heating device 23 heats the working fluid 5 to the second target temperature, and monitors the temperature of the working fluid 5 in real time through the temperature detection device 22. The self-rotating platform 20 drives the anode 4 to revolve in a circular motion around the workpiece 1, or the workpiece 1 is connected to other self-rotating platforms or motors to keep it rotating at a constant speed, and the anode 4 remains stationary. Then, a voltage is applied to the workpiece and the anode 4 as the cathode. In this process, the metal ions accept electron transfer and are reduced to metal atoms and deposited in the micro-pattern hollow 210, thereby realizing the electrochemical deposition of a large-area microstructure of an undevelopable curved surface.

[0110] Finally, the workpiece 1 after the electrodeposition is immersed in an organic solvent to remove the photolithography dry film layer 2 on the surface thereof, thereby fabricating a large-area array structure or a micro-nano pattern on the non-developable curved surface 110 .

[0111] Therefore, the present application adopts the paper-cutting method and the dynamic electrochemical deposition manufacturing process to solve the manufacturing problems of mask wrinkles, low lithography precision, and uneven deposition effect of complex curved surface parts. The device proposed by the present invention optimizes mask lithography and dynamic electrochemical deposition. After the CNC workbench 13 completes lithography in the mask lithography area, the CNC machine tool 8 is controlled to move the CNC workbench 13 to the dynamic electrochemical deposition area. The self-rotating platform drives the anode to orbit around the workpiece, making its structure simple and ensuring processing efficiency.

[0112] The present invention provides a method and method for preparing a large-area microstructure of a non-expandable curved surface based on the paper-cutting method and a device. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for preparing a large-area microstructure of an undevelopable curved surface based on the paper-kirigami method, characterized in that: include: S1, forming a photolithography dry film layer (2) on a non-developable curved surface (110) of a workpiece (1); S2, dividing the non-developable curved surface (110) into a plurality of developable small-area microelements (111) that are approximately plane-like through digital modeling analysis; unfolding the divided non-developable curved surface (110) to obtain an approximately two-dimensional shearing pattern (120); S3, cutting the flexible photolithography mask plate (3) according to the shearing pattern (120), and after cutting, laminating it to the surface of the photolithography dry film layer (2) on the side away from the non-expandable curved surface (110); and forming the desired micro-pattern hollowing (210) on the photolithography dry film layer (2) through exposure and development; S4, introducing a working liquid (5) between the workpiece (1) and the anode (4), applying a voltage to the workpiece (1) serving as a cathode and the anode (4), and performing electrochemical deposition in the micro-pattern hollow (210); S5, removing the photolithography dry film layer (2), and preparing a large-area array structure or a micro-nano pattern on the non-developable curved surface (110).

2. The method for preparing a large-area microstructure on a non-developable curved surface based on the paper-kirigami method according to claim 1, characterized in that: The S1 comprises the following sub-steps: The photolithography dry film (6) is stretched, and the stretching force in each direction is kept the same. During the stretching process, the photolithography dry film (6) undergoes elastic deformation, so that the photolithography dry film (6) can adapt to the contour of the non-expandable curved surface (110) of the workpiece (1), and after the photolithography dry film (6) completely covers the non-expandable curved surface (110) of the workpiece (1), it is hot-pressed to form the photolithography dry film layer (2) on the non-expandable curved surface (110) of the workpiece (1); Alternatively, the photoresist is evenly coated on the non-developable curved surface (110) of the workpiece (1) using a spin coating method, and the workpiece (1) is then placed on a hot plate for pre-baking, thereby forming the photolithography dry film layer (2) on the non-developable curved surface (110) of the workpiece (1).

3. The method for preparing a large-area microstructure of a non-expandable curved surface based on the paper-kirigami method according to claim 1, characterized in that: In S4, the workpiece (1) and the anode (4) are placed in a relative rotation state.

4. The method for preparing a large-area microstructure of a non-expandable curved surface based on the paper-kirigami method according to claim 1, characterized in that: In S2, the non-developable curved surface (110) is divided into a plurality of developable small-area micro-elements (111) that are approximately plane-like, and different structural division densities are set according to different curvatures of different areas in the non-developable curved surface (110); A higher structure division density is set for high curvature areas, and a lower structure division density is set for low curvature areas.

5. The method for preparing a large-area microstructure on a non-developable curved surface based on the paper-kirigami method according to claim 1, characterized in that: The shape of the small-area element (111) is determined according to the different shapes and sizes of the non-developable curved surface (110); the shape of the small-area element (111) is any one of a ring, a sector and a plane polygon, or a combination of several of them.

6. The method for preparing a large-area microstructure of a non-expandable curved surface based on the paper-kirigami method according to claim 1, characterized in that: The flexible photolithography mask plate (3) is a bendable and non-stretchable mask plate, selected from one of a PET mask plate, a PDMS mask plate, a PI mask plate and an organic thin film mask plate; The light-proof pattern of the flexible photolithography mask plate (3) is divided into a linear structure pattern, a dot structure pattern and a composite structure pattern according to the purpose.

7. The method for preparing a large-area microstructure on a non-developable curved surface based on the paper-kirigami method according to claim 1, characterized in that: The anode (4) is designed according to the shape and size of the non-developable curved surface (110), and the anode (4) is designed as a linear anode (401), a sheet anode (402) with the same curvature as the workpiece, or a fully wrapped anode (403); The linear anode (401) and the workpiece-same-curvature sheet anode (402) both maintain the same curvature as the non-developable curved surface (110), and are configured to be able to perform cyclic reciprocating motion around the non-developable curved surface (110) of the workpiece (1); The fully wrapped anode (403) has the same shape as the workpiece (1), and can completely cover the non-expandable curved surface of the workpiece (1), and can retain a processing gap between the non-expandable curved surface of the workpiece (1) when covering.

8. The method for preparing a large-area microstructure on a non-developable curved surface based on the paper-kirigami method according to claim 7, characterized in that: In S4, when the anode (4) is the linear anode (401) or the workpiece is a sheet anode (402) with the same curvature as the workpiece, the workpiece (1) and the anode (4) are completely immersed in the working fluid (5); when the anode (4) is the fully enclosed anode (403), the working fluid (5) is supplied in the form of a flushing liquid to continuously flush the machining gap between the workpiece (1) and the anode (4).

9. The method for preparing a large-area microstructure on a non-developable curved surface based on the paper-kirigami method according to claim 1, characterized in that: The exposure adopts a digitally controlled multi-point light source (7) or a linear light source; The digitally controlled multi-point light source (7) comprises a plurality of point light sources, and the plurality of point light sources are evenly distributed in various directions of the non-developable curved surface (110) and can illuminate the non-developable curved surface (110) at the same time, so as to ensure that each part of the non-developable curved surface (110) receives the same illumination parameters; The linear light source can emit linear light with the same curvature as the non-developable curved surface (110); when the workpiece rotates, the linear light emitted by the linear light source passes over the non-developable curved surface (110) to eliminate light scattering.

10. A device for preparing a large-area microstructure on a non-expandable curved surface based on the paper-kirigami method according to claim 1, characterized in that: It includes a numerical control machine tool (8), a deposition tank (9), a frame (10), a liftable mechanical arm (11), a mask photolithography system, an electrochemical deposition processing system and a power supply system; The numerically controlled machine tool (8) comprises a movable numerically controlled worktable (13); a deposition tank (9) is fixedly mounted on the numerically controlled worktable (13); a workpiece fixing fixture (14) for fixing the workpiece (1) is arranged in the deposition tank (9); The frame (10) is liftably connected to the top of the machine tool base via a liftable mechanical arm (11); the mask photolithography system and the electrochemical deposition processing system are both installed on the frame (10) and are both arranged on the moving path of the numerical control workbench (13); The mask photolithography system comprises a stretching mechanism (15), a movable hot pressing mold (16), a heating oil cylinder (17), a pressure gauge (18), a numerically controlled multi-point light source (7) and a light source adjustment device (19); the stretching mechanism (15) is used to uniformly clamp and stretch the photolithography dry film (6) from which the thick protective film has been removed; the movable hot pressing mold (16) is connected to the telescopic end of the heating oil cylinder (17) and is heated and maintained above the photolithography dry film (6); when the numerically controlled workbench (13) moves to When the workpiece (1) and the movable hot pressing mold (16) are placed opposite to each other in the vertical direction and the heating oil cylinder (17) heats the movable hot pressing mold (16) to a hot pressing target temperature, the heating oil cylinder (17) drives the movable hot pressing mold (16) to move downward until the photolithography dry film (6) is hot pressed and attached to the non-expandable curved surface (110) of the workpiece (1); the numerically controlled multi-point light source (7) is used to provide light with the same illumination parameters to each part of the non-expandable curved surface of the workpiece (1); The electrochemical deposition processing system comprises a self-rotating platform (20), an anode clamp (21) for fixing an anode (4), a temperature detection device (22) and a heating device (23); the self-rotating platform (20) is installed on the liftable mechanical arm (11); the anode clamp (21) is fixedly connected to the bottom of the self-rotating platform (20); the heating device (23) is used to heat the working fluid (5) in the deposition tank (9) to a second target temperature; the temperature detection device (22) is used to monitor the temperature of the working fluid (5) in the deposition tank (9) in real time; The power supply system comprises a first power supply (121) and a high-frequency bidirectional pulse current power supply (122), wherein the first power supply (121) is used to supply power to the mask lithography system; the positive electrode of the high-frequency bidirectional pulse current power supply (122) is connected to the anode (4), and the negative electrode is connected to the workpiece (1), and when a working fluid (5) is introduced between the workpiece (1) and the anode (4), a closed circuit is realized; The device is configured to, after the mask photolithography of the workpiece (1) is completed, control the CNC machine tool (8) to move the CNC worktable (13) to drive the workpiece (1) to move synchronously to the bottom of the self-rotating platform (20) and to allow the anode (4) to be completely immersed in the working fluid (5) in the deposition tank (9) and to leave a processing gap between the anode (4) and the workpiece (1); the self-rotating platform (20) can drive the anode (4) to perform a revolving circular motion around the workpiece (1) through the anode fixture (21), thereby realizing the preparation of a large-area microstructure of an undevelopable curved surface.

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