High-energy laser micro-nano structure manufacturing method based on reflector path optical glass patterning design

Abstract

The invention discloses a high-energy laser micro-nano structure manufacturing method based on reflector path optical glass patterning design, and belongs to the technical field of metal material surface processing. The manufacturing method of the high-energy laser micro-nano structure provided by the invention comprises the following steps: according to a target micro-nano structure, coating an energy absorption material with a specific pattern on the surface of optical glass to prepare patterned optical glass; the patterned optical glass is arranged at a specific position of an external light path between the converging laser emitting end of the laser shock device and the target material; and performing laser shock treatment on the surface of the target material to generate a target micro-nano structure on the surface of the target material. According to the invention, simple construction of a complex micro-nano structure can be realized, cross-scale control of the size of the micro-nano structure can be realized, the processing difficulty is greatly reduced, the cost is low, the position of the patterned optical glass can be changed according to actual scaling requirements, and the flexibility is high.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material surface processing, and in particular to a high-energy laser micro-nano structure manufacturing method based on external light path optical glass patterning design. Background Art

[0002] The information disclosed in the background of the invention is only intended to enhance the understanding of the overall background of the invention and should not be necessarily regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] As one of the core technologies in the field of modern precision machining, laser micro-nano manufacturing technology has shown great application potential in the fields of medicine, aerospace, etc. The traditional "top-down" laser micro-nano manufacturing process mainly relies on photolithography technology to achieve micro-nano structure formation, and its process accuracy is limited by the beam resolution and etching uniformity of the photolithography process. However, the photolithography process has strict requirements on the quality of the laser beam (such as beam spot size and energy distribution uniformity), resulting in high equipment costs and low process economy.

[0004] The patent with the authorization announcement number CN113967796B discloses a method for preparing a super-hydrophobic surface by laser impact embossing micro-nano particles on the surface of aluminum alloy. This patent requires complex pre-treatment and post-treatment processes, and it uses the mixing ratio of micron / nanoparticles to control the formed micro-nano structure. In practical applications, it is easy to have uneven distribution problems, resulting in poor consistency of the surface micro-nano structure. The patent with the authorization announcement number CN115703167B realizes the manufacture of ultra-fine metal micro-nano structures by using ultra-high strain rate multi-step laser impact embossing process and hard vertical channel high-precision surface mold. This patent requires the use of hard ceramic or alloy molds, which have extremely high processing precision requirements, high manufacturing costs and easy wear, making it difficult to achieve large-scale production, and it needs to be impact embossed in two steps, with a long process cycle and high energy consumption.

[0005] Therefore, developing new micro-nano manufacturing technologies that are low-cost, easy to implement and highly flexible has become a technical challenge that the industry urgently needs to solve. Summary of the invention

[0006] In view of this, the present invention provides a high-energy laser micro-nano structure manufacturing method based on the patterned design of external light path optical glass. The present invention "pre-places" the micro-nano structure design in the laser propagation path, breaking through the traditional process's reliance on direct processing of the target surface, and achieving low-cost and high-flexibility manufacturing of micro-nano structures in a high-energy laser environment.

[0007] The present invention provides a method for manufacturing a high-energy laser micro-nano structure based on an external light path optical glass pattern design, comprising the following steps:

[0008] According to the target micro-nano structure, a specific pattern of energy-absorbing material is coated on the surface of the optical glass to prepare patterned optical glass;

[0009] The patterned optical glass is arranged at a specific position of the external light path between the converging laser emitting end of the laser impact device and the target material; the target material is located between the converging laser emitting end and the theoretical focus of the converging laser;

[0010] An absorption layer and a constraint layer are sequentially arranged on the surface of the target material, and a laser shock treatment is performed on the surface of the target material to generate a target micro-nano structure on the surface of the target material.

[0011] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0012] (1) The present invention arranges patterned optical glass in the external light path, and the area not coated with energy-absorbing material will not affect the laser propagation path, and a concave structure will be formed on the surface of the target material after the laser impact; while the area coated with energy-absorbing material will block the laser from passing through, and then a convex structure will be formed on the corresponding target surface. Therefore, the present invention can realize the simple construction of complex micro-nano structures; at the same time, based on the convergence characteristics of the converged laser, the pattern size of the patterned optical glass is larger than the target micro-nano structure size of the target material, and there is a certain scaling ratio relationship. Therefore, the present invention can realize cross-scale control of the size of the micro-nano structure, greatly reducing the processing difficulty and lowering the cost. In addition, the position of the patterned optical glass can be changed according to the actual scaling requirements, and the flexibility is higher.

[0013] (2) The present invention does not require complicated pre-treatment / post-treatment steps, and directly realizes energy regulation through the patterned design of the external optical path optical glass, eliminating the steps of precision mold processing, particle mixing and ultrasonic cleaning, and significantly reducing the cost of equipment and consumables. At the same time, the present invention generates micro-nano structures in one step through energy modulation at the optical path end, avoiding multi-step laser impact, improving processing efficiency, and reducing processing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute an improper limitation of the present invention. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 is a schematic diagram of a high-energy laser micro-nanostructure manufacturing process according to an embodiment of the present invention;

[0016] In the figure, 1. Laser; 2. External light path; 3. Patterned optical glass; 4. Area on the target surface to be processed; 5. Micro-nano structure. DETAILED DESCRIPTION

[0017] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0018] The present invention provides a method for manufacturing a high-energy laser micro-nano structure based on an external light path optical glass pattern design, comprising the following steps:

[0019] According to the target micro-nano structure, a specific pattern of energy-absorbing material is coated on the surface of the optical glass to prepare patterned optical glass;

[0020] The patterned optical glass is arranged at a specific position of the external light path between the converging laser emitting end of the laser impact device and the target material; the target material is located between the converging laser emitting end and the theoretical focus of the converging laser;

[0021] An absorption layer and a constraint layer are sequentially arranged on the surface of the target material, and a laser shock treatment is performed on the surface of the target material to generate a target micro-nano structure on the surface of the target material.

[0022] In the present invention, the laser emitted by the laser is a convergent beam, and the target material is located in front of the theoretical focus of the laser. Therefore, the beam diameter gradually decreases with the propagation distance. When the laser impacts, the convergent laser forms a focal spot on the surface of the target material. The present invention firstly accurately coats the energy-absorbing material on the surface of the optical glass according to the geometric characteristics (convex or concave) of the target micro-nano structure to form an enlarged pattern corresponding to the target micro-nano structure. The patterned optical glass is arranged in the convergent external light path between the laser and the target material, and the natural convergence characteristics of the laser beam are used to project the energy-absorbing pattern onto the surface of the target material in proportion. If a convex structure needs to be formed in a specific area on the surface of the target material, the energy-absorbing material covers the corresponding position of the optical glass; if a concave structure needs to be formed in a specific area on the surface of the target material, the energy-absorbing material is distributed in its peripheral area. The energy-absorbing material locally absorbs the laser energy to form a non-uniform plasma shock wave distribution on the surface of the target material, drives the material to undergo selective plastic deformation, and directly generates the target micro-nano structure, which can realize the precise manufacturing of specific target micro-nano structures. By adjusting the zoom factor, continuous scaling from micron-scale to nanoscale structures can be achieved in a single step, and cross-scale control of the size of micro-nano structures can be achieved, which greatly reduces the difficulty of processing, reduces costs, and increases flexibility. The present invention innovates the "target end design" of traditional laser micro-nano manufacturing into "energy modulation at the optical path end", and through the three-in-one technical path of preparation of patterned optical glass for external optical paths - dynamic position adjustment - laser convergence coordination, it solves the core problems of existing processes that rely on physical molds, have low processing freedom, and poor material adaptability, and realizes low-cost, high-precision, cross-scale manufacturing of micro-nano structures in high-energy laser environments.

[0023] In the present invention, the energy absorbing material is black paint or black tape, and the coating thickness is more than 500 μm. Under laser irradiation, the energy absorbing material absorbs laser energy in a specific area, forming local energy attenuation, thereby generating non-uniform plasma shock wave distribution on the target surface. The thickness of the energy-absorbing material quantitatively affects the attenuation degree of the pulsed laser energy, and then indirectly realizes the degree of fluctuation of the micro-nano structure by adjusting the intensity of the shock wave: there is a threshold value for the thickness of the energy-absorbing material that cannot be completely ablated, and this value is specifically determined by the laser energy planned for the laser shock; the higher the laser energy value, the more the energy-absorbing material is consumed, resulting in a larger threshold value for complete ablation of the material; when the energy-absorbing material is thick enough and the thickness exceeds the threshold value, the laser energy is completely consumed at the patterned optical glass of the external light path, at which time the area on the target surface corresponding to the energy-absorbing material coating has no laser shock wave effect, and the height difference between the raised and recessed structures depends only on the amount of plastic deformation of the target surface corresponding to the area not coated with the energy-absorbing material; when the thickness of the energy-absorbing material does not exceed the threshold value, the laser energy cannot be completely consumed at the external light path glass, at which time the area on the target surface corresponding to the energy-absorbing material coating has an attenuated laser shock wave effect, and the height difference between the raised and recessed structures depends on the difference in the amount of plastic deformation of the target surface corresponding to the area not coated with the energy-absorbing material and the area coated with the energy-absorbing material.

[0024] In the present invention, the side of the patterned optical glass coated with the energy absorbing material faces away from the converging laser emission end to reduce the effect of the ablation of the energy absorbing material on the laser energy penetration in the surrounding area. Furthermore, the coating thickness error value is less than 5% to avoid energy distribution distortion. The formula of the coating thickness error value is as follows:

[0025]

[0026] In the present invention, the coating step is implemented by direct writing, spraying or photolithography. The present invention does not impose any special restrictions on the specific implementation method, and it can be implemented by a common method in the art.

[0027] In the present invention, the size of the patterned optical glass is y, the size of the target micro-nano structure on the target surface is x, the scaling factor is M, M=x / y, the distance between the convergent laser emitting end of the laser impact device and the target is L2, and the theoretical focal length of the convergent laser of the laser impact device is f. Then, the calculation formula of the distance L1 between the patterned optical glass and the target is as follows:

[0028]

[0029] It should be noted that the theoretical focal length of the converging laser refers to the distance between the emitting end of the converging laser and the position where the laser focusing area is a point without area (the theoretical focus). Based on the characteristics of the converging laser, x < y, so M < 1. When the value of M is larger, the values of x and y are closer, and the distance L1 between the patterned optical glass and the target is closer; when the value of M is larger, y is larger, and the distance L1 between the patterned optical glass and the target is farther. Since the target is located between the emitting end of the converging laser and the theoretical focus of the converging laser, L2 < f. The present invention can select the scaling factor M as needed, and then determine the placement position of the patterned optical glass according to the theoretical focal length f of the converging laser and the distance L2 between the emitting end of the converging laser and the target.

[0030] In the present invention, 0.02 < M < 0.8, and further preferably 0.05 < M < 0.5. The value of M should not be too large. If it is too large, the distance L1 between the patterned optical glass and the target will be too close, which will not only significantly weaken the scaling effect, but also cause the patterned optical glass to bear too much laser impact energy, possibly causing damage to the optical glass.

[0031] In the present invention, corresponding to the morphological size of the micro-nano structure, the diameter of the laser spot on the surface of the target is preferably 50 - 1000 μm, and more preferably 100 - 500 μm.

[0032] In the present invention, the diameter of the spot at the emitting end of the converging laser of the laser shock device is 10 - 30 mm.

[0033] In the present invention, the optical glass is K9 glass. K9 glass has high light transmittance, low dispersion and good stability, and is suitable for high-precision imaging, laser technology and optical requirements under harsh environments. Further, the thickness of the optical glass is 1 - 3 mm.

[0034] In the present invention, the material of the absorption layer is black paint or black tape. The absorption layer is the material basis for laser-induced ablation to form plasma, and the plasma forms an impact effect within a limited time and space; the material of the constraint layer is K9 glass or deionized water. If K9 glass is used, it needs to be mechanically pressed on the absorption layer material, and air bubbles between the K9 glass and the absorption layer material should be avoided; if deionized water is used, the water flow velocity needs to be controlled to keep the water flow on the surface of the absorption layer stable and the thickness uniform.

[0035] The technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0036] Embodiment

[0037] This embodiment provides a method for manufacturing high-energy laser micro-nano structures based on the patterned design of external optical path optical glass. The schematic diagram of the manufacturing process is as Figure 1 shown.

[0038] (1) Target material and laser parameters:

[0039] Target material: 304 stainless steel plate, thickness 1mm, surface roughness Ra≤0.1μm.

[0040] Laser 1 type: Nd:YAG pulse laser; wavelength: 1064nm; pulse energy: 5J; pulse width: 18ns; repetition frequency: 10Hz; emission end spot diameter: 20mm; laser theoretical focal length: f=304.5mm (natural convergent beam).

[0041] (2) Preparation of patterned optical glass 3

[0042] ①Pattern design:

[0043] Target micro-nano structure: rectangular depression array, unit size 200μm×80μm, depression spacing 2μm.

[0044] According to the target recess array, a 4 mm×1.6 μm rectangular energy absorption area is designed on the optical glass surface, and the spacing between the energy absorption areas is 0.4 mm (scaled according to M=0.05).

[0045] ②Coating process:

[0046] Laser direct writing technology is used to coat the surface of optical glass with a pyrolytic graphite coating with a thickness of 600μm±18μm (error 3%); the edge clarity of the coating is ≤2μm to ensure the accuracy of energy distribution.

[0047] (2) Optical path arrangement and calibration

[0048] Target position: L2 = 300 mm (between the laser and the focus, L2 <f);

[0049] Place the patterned optical glass 3 in the laser external light path 2, installation position:

[0050]

[0051] The patterned optical glass 3 is 85.5 mm away from the target surface area 4 to be processed, and is 214.5 mm away from the laser 1 .

[0052] Fixing the patterned optical glass 3: The patterned optical glass 3 is mounted on the electric translation stage with a positioning accuracy of ±0.05 mm.

[0053] Laser beam alignment: Use a CCD camera for real-time monitoring to ensure that the center of the patterned optical glass 3 coincides with the center of the laser spot (deviation ≤ 5μm).

[0054] (3) Laser shock processing

[0055] An absorption layer and a constraint layer are coated on the surface of the target material from the inside out, the absorption layer material is 3M black tape, and the constraint layer material is K9 glass; a single laser impact (the laser spot diameter on the target surface is about 300 μm), the laser passes through the patterned optical glass 3, the energy absorption area absorbs energy and generates a local shock wave; the energy is reflected / scattered in the non-energy absorption area, and the corresponding position of the target material is subjected to the shock wave pressure to form a micro-nano structure 5 (recess array), which corresponds to the pattern on the patterned optical glass 3.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass, characterized in that: The steps include: According to the target micro-nano structure, a specific pattern of energy-absorbing material is coated on the surface of the optical glass to prepare patterned optical glass; The patterned optical glass is arranged at a specific position of the external light path between the converging laser emitting end of the laser impact device and the target material; the target material is located between the converging laser emitting end and the theoretical focus of the converging laser; An absorption layer and a constraint layer are sequentially arranged on the surface of the target material, and a laser shock treatment is performed on the surface of the target material to generate a target micro-nano structure on the surface of the target material.

2. The method for manufacturing a high-energy laser micro-nano structure based on the patterned design of external light path optical glass according to claim 1, characterized in that: The energy absorbing material is black paint or black tape, and the coating thickness is more than 500 μm.

3. The method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass according to claim 1, characterized in that: The coating thickness error value is less than 5%, and the formula of the coating thickness error value is as follows:

4. The method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass according to claim 1, characterized in that: The coating step is achieved by direct writing, spraying or photolithography.

5. The method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass according to claim 1, characterized in that: The size of the patterned optical glass is y, the size of the target micro-nano structure on the target surface is x, the scaling factor is M, M=x / y, the distance between the converging laser emission end of the laser impact device and the target is L2, and the theoretical focal length of the converging laser of the laser impact device is f. Then, the calculation formula for the distance L1 between the patterned optical glass and the target is as follows:

6. The method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass according to claim 5, characterized in that: 0.02<M<0.8。 7. The method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass according to claim 5, characterized in that: The diameter of the laser spot on the target surface is preferably 50 to 1000 μm.

8. The method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass according to claim 1, characterized in that: The spot diameter of the converging laser emitting end of the laser impact device is 10 to 30 mm.

9. The method for manufacturing a high-energy laser micro-nano structure based on patterned design of external light path optical glass according to claim 1, characterized in that: The optical glass is K9 glass, and the thickness of the optical glass is 1 to 3 mm.

10. The method for manufacturing high-energy laser micro-nanostructure based on patterned design of external light path optical glass according to claim 1, characterized in that: The material of the absorption layer is black paint or black tape, and the material of the constraint layer is K9 glass or deionized water.

Images