A method for coating the radar antenna reflector of an LMC laser sputtering energy regulation

Abstract

The application discloses a kind of LMC laser sputtering energy regulation radar antenna reflector coating methods, it is related to radar antenna manufacturing technical field, the method is by establishing the high-precision three-dimensional curvature atlas of antenna reflector and partition, scanning path is dispersed as grid node carrying local curvature radius and laser incidence angle, based on energy-deposition relationship each node target single-pulse energy and target spot overlap rate are solved, and then in sputtering process, laser energy is adjusted in real time using acoustooptic modulation or pulse power and scanning speed and pulse frequency are synchronously controlled, realize the accurate particle kinetic energy and flux compensation of curvature mutation area, it can be deposited on parabolic surface, hyperboloid, shaped surface and other complex reflector metal or dielectric coating with uniform thickness, residual stress and microstructure height, eliminate the film uneven and shape error caused by surface geometry characteristics, improve the surface shape precision and electrical performance consistency of antenna reflector.

Description

Technical Field

[0001] This invention relates to the field of radar antenna manufacturing technology, specifically to a method for coating radar antenna reflective surfaces using LMC laser sputtering energy modulation. Background Technology

[0002] Radar antenna reflectors are typically complex geometric shapes such as parabolic, hyperboloid, or shaped surfaces. To ensure the radar's beam pointing accuracy and low sidelobe performance, a highly conductive metal layer (such as gold, silver, or aluminum) or a dielectric thin film must be deposited on the reflector surface. The coating must also have extremely high thickness uniformity, a consistent residual stress state, and a uniform microtexture to prevent additional shape and position errors from occurring on the reflector surface.

[0003] Laser sputtering technologies (such as pulsed laser deposition and LMC) have unique advantages in high-quality thin film preparation due to their excellent composition preservation and high-energy particle deposition characteristics. However, when laser sputtering is applied to large-size, curved substrates with large curvature variations, the significant differences in the radius of curvature and laser beam incident angle at different locations on the surface cause changes in the flux, particle kinetic energy, and incident direction of the plasma plume generated by laser sputtering reaching the substrate surface. This results in variations in deposition rate, film density, residual stress, and grain orientation with the position of the curved surface. Traditional fixed-energy laser sputtering or passive compensation methods through substrate tilting or rotation cannot fundamentally eliminate the film inhomogeneities introduced by the geometric characteristics of the curved surface itself, ultimately affecting the surface accuracy and electrical performance of the antenna reflector.

[0004] Therefore, there is an urgent need for a coating method that can actively sense the geometric characteristics of the antenna reflector surface and adaptively control the laser sputtering energy in order to obtain coatings with consistent thickness, stress and texture on complex curved surfaces. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for coating radar antenna reflectors using LMC laser sputtering energy control. This method establishes a high-precision three-dimensional curvature map of the antenna reflector and divides it into partitions. The scanning path is discretized into grid nodes carrying local curvature radii and laser incident angles. Based on the energy-deposition relationship, the target single-pulse energy and target spot overlap rate of each node are calculated. Then, during the sputtering process, the laser energy is adjusted in real time using acousto-optic modulation or pulse power supply, and the scanning speed and pulse frequency are controlled synchronously. This achieves precise particle kinetic energy and flux compensation in curvature transition regions. It can deposit metal or dielectric coatings with highly uniform thickness, residual stress, and microstructure on complex reflector surfaces such as parabolic surfaces, hyperboloids, and shaped surfaces, eliminating film inhomogeneity and shape errors caused by surface geometry, and improving the surface accuracy and electrical performance consistency of the antenna reflector.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation, the specific steps of which are as follows:

[0007] S100. Establish a high-precision three-dimensional curvature map of the antenna reflector and divide the antenna reflector into a flat curvature region, a gradually changing curvature region, and a sudden curvature region based on the curvature change.

[0008] S200. Plan a laser sputtering scanning path on the antenna reflector surface, discretize the scanning path into spatially ordered grid nodes, and assign a local radius of curvature and laser incident angle to each grid node.

[0009] S300. Based on a pre-built energy-deposition relationship model, for each grid node, the target single-pulse energy and target spot overlap rate required to obtain a uniform coating are calculated according to the local radius of curvature and laser incident angle of the grid node.

[0010] S400. During LMC laser sputtering, the grid node currently being acted upon by the laser is acquired in real time. The laser pulse energy is instantaneously adjusted to the target single pulse energy corresponding to the grid node through an acousto-optic modulator and a pulse power supply. At least one of the scanning speed and the laser pulse repetition frequency is adjusted to make the actual spot overlap rate reach the target spot overlap rate corresponding to the grid node.

[0011] S500, continue executing S400 until all grid nodes are deposited, forming a coating with uniform thickness, residual stress, and microtexture on the antenna reflector surface.

[0012] Furthermore, in S100, the method for dividing the curvature abrupt change region, the curvature gradual change region, and the curvature flat region is as follows:

[0013] Calculate the rate of change of the local radius of curvature along the arc length at each point on the antenna reflector surface. When the rate of change of the local radius of curvature in any region on the surface within a unit arc length is greater than a preset threshold, the region is regarded as a curvature abrupt change region.

[0014] When the rate of change is less than or equal to the preset threshold and the local radius of curvature of the region is greater than the first preset value, the region is designated as a curvature flat region.

[0015] The region on the surface other than the curvature abrupt region and the curvature flat region is defined as the curvature gradual change region.

[0016] Furthermore, in S100, the high-precision three-dimensional curvature map includes:

[0017] Obtain point cloud data of the antenna reflector and reconstruct a surface mathematical model of the antenna reflector based on the point cloud data;

[0018] The surface mathematical model is subjected to surface differential geometry calculations to obtain the Gaussian curvature, mean curvature, and principal curvature radius at each local point on the surface, forming a curvature distribution map that characterizes the global geometric features of the antenna reflector.

[0019] Furthermore, in S200, the laser incident angle is determined as follows:

[0020] In the spatial coordinate system of the LMC laser sputtering system, the surface normal vector of the grid node is taken as the reference direction, and the unit direction vector of the laser beam central axis is taken as the incident direction. The spatial angle between the surface normal vector and the unit direction vector of the laser beam central axis is calculated, and the spatial angle is taken as the laser incident angle of the grid node.

[0021] For the same grid node, when the spatial relative position of the surface normal vector and the laser beam central axis changes due to the posture adjustment of the scanning motion mechanism, the laser incident angle is dynamically updated according to the real-time spatial relative position relationship.

[0022] In S200, the local radius of curvature assigned to the mesh node is the average radius of curvature at the mesh node calculated by surface differential geometry.

[0023] Furthermore, in S300, the construction process of the energy-deposition relationship model is as follows:

[0024] Laser sputtering experiments were conducted on a planar substrate with a laser incident angle of zero degrees to determine the reference single-pulse energy required to obtain a standard coating quality. Overlap rate with reference spot ;

[0025] A series of deposition experiments were conducted by varying the substrate radius of curvature and the laser incident angle. The deposition rate and film properties under different conditions were measured, and a system based on the local radius of curvature was established. and laser incident angle Energy compensation coefficient of the independent variable and overlap rate compensation coefficient ;

[0026] The energy-deposition relationship model is expressed as follows: , For any grid node The grid node Target single pulse energy The grid node Target spot overlap rate ,in, For the grid node The local radius of curvature, For the grid node The laser incident angle;

[0027] For grid nodes located in regions of abrupt curvature change, when the deposition rate falls below baseline conditions due to a decrease in the local radius of curvature of the grid node or an increase in the laser incident angle, the energy compensation coefficient... The value is greater than 1, and the overlap rate compensation coefficient is... A value greater than 1 is selected to compensate for insufficient particle flux and decreased atomic kinetic energy caused by geometric factors by increasing the target single pulse energy and the target spot overlap rate.

[0028] Furthermore, in S400, when adjusting the scanning speed and laser pulse repetition frequency, according to... To implement control, among which... For the grid node The overlap rate of the target light spot at that location. For the laser beam at the grid node Scanning speed at that location The diameter of the laser spot formed by the laser beam on the surface of the antenna reflector is given. The laser pulse repetition frequency is adjusted in real time. and At least one parameter in the equation, such that Established.

[0029] Furthermore, the S400 also includes a tiered control strategy:

[0030] For mesh nodes located in the curvature abrupt change region, the single pulse energy adjustment step size of the acousto-optic modulator is set to the first step length precision, and the response frequency of the scanning motion mechanism and / or laser pulse repetition frequency is set to the first response frequency;

[0031] When the curvature is flat, the single pulse energy adjustment step size of the acousto-optic modulator is set to the second step size accuracy, and the response frequency of the scanning motion mechanism and / or the laser pulse repetition frequency is set to the second response frequency.

[0032] The first step length accuracy is less than the second step length accuracy, and the first response frequency is greater than the second response frequency, so that the curvature abrupt region obtains higher energy regulation resolution and faster dynamic response speed than the curvature flat region.

[0033] Furthermore, the coating material is any one of the following metals: high-purity gold, high-purity silver, and high-purity aluminum, or a dielectric material.

[0034] Furthermore, the radar antenna reflector is any one of a parabolic antenna reflector, a hyperboloid antenna reflector, or a shaped curved surface antenna reflector.

[0035] Compared with existing technologies, this method for coating radar antenna reflectors using LMC laser sputtering energy modulation has the following advantages:

[0036] I. This invention establishes a high-precision three-dimensional curvature map of the antenna reflector surface, using the local curvature radius of the surface and the laser incident angle as input parameters. It independently calculates the target single-pulse energy and target spot overlap rate for each grid node using the energy-deposition relationship. During laser sputtering, instantaneous energy adjustment is performed through acousto-optic modulation or pulsed power supply. This method actively transforms the geometric differences of the surface into precisely controllable changes in energy and scanning parameters, enabling directional compensation of deposition rates and atomic kinetic energy in flat curvature regions, gradually changing regions, and abrupt curvature regions. This results in a coating with highly uniform thickness, residual stress, and microtexture across the entire domain, solving the problems of uneven film thickness and stress asymmetry caused by differences in surface morphology under traditional fixed-energy sputtering. This ensures the spatial consistency of the amplitude and phase response of the radar antenna reflector surface.

[0037] Second, this invention discretizes the scanning path into spatially ordered grid nodes and assigns each node independent local radius of curvature and laser incident angle parameters. The target single pulse energy and target spot overlap rate required for each node are calculated through energy compensation coefficient and overlap rate compensation coefficient. Among them, nodes in the curvature change region obtain higher single pulse energy and spot overlap rate settings due to the increase of incident angle or decrease of curvature radius. During sputtering, higher precision energy adjustment resolution and faster dynamic response frequency are automatically matched to nodes in the curvature change region, so that the insufficient particle flux and decrease of atomic kinetic energy caused by geometric factors in these areas are accurately compensated, effectively avoiding defects such as local coating that is too thin, loose or stress concentrated, and improving the integrity and consistency of the coating in the extreme geometric position of complex curved surface.

[0038] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0040] Figure 1 This is a flowchart illustrating the steps of a radar antenna reflector coating method with LMC laser sputtering energy modulation in an embodiment of the present invention.

[0041] Figure 2 This is the process for constructing a high-precision three-dimensional curvature map in an embodiment of the present invention;

[0042] Figure 3 A flowchart illustrating the process of assigning local curvature radii and laser incident angles to mesh nodes in this embodiment of the invention. Detailed Implementation

[0043] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0044] This invention provides a method for coating radar antenna reflector surfaces using LMC laser sputtering energy modulation. This method aims to solve the problems of uneven coating thickness, residual stress, and microtexture caused by differences in local radii of curvature and laser incident angle on radar antenna reflector surfaces with complex curved geometric features. Figure 1 As shown, the specific steps of this method are as follows:

[0045] S100. Establish a high-precision three-dimensional curvature map of the antenna reflector and divide the antenna reflector into a flat curvature region, a gradually changing curvature region, and a sudden curvature region based on the curvature change.

[0046] S200. Plan a laser sputtering scanning path on the antenna reflector surface, discretize the scanning path into spatially ordered grid nodes, and assign a local radius of curvature and laser incident angle to each grid node.

[0047] S300. Based on a pre-built energy-deposition relationship model, for each grid node, the target single-pulse energy and target spot overlap rate required to obtain a uniform coating are calculated according to the local radius of curvature and laser incident angle of the grid node.

[0048] S400. During LMC laser sputtering, the grid node currently being acted upon by the laser is acquired in real time. The laser pulse energy is instantaneously adjusted to the target single pulse energy corresponding to the grid node through an acousto-optic modulator and a pulse power supply. At least one of the scanning speed and the laser pulse repetition frequency is adjusted to make the actual spot overlap rate reach the target spot overlap rate corresponding to the grid node.

[0049] S500, continue executing S400 until all grid nodes are deposited, forming a coating with uniform thickness, residual stress, and microtexture on the antenna reflector surface.

[0050] Step S100: Establish a high-precision three-dimensional curvature map of the antenna reflector and divide the antenna reflector into a flat curvature region, a gradually changing curvature region, and a sudden curvature region based on the curvature changes.

[0051] In a preferred embodiment, step S100 is used to establish a high-precision three-dimensional curvature map of the antenna reflector, and to divide the antenna reflector into a flat curvature region, a gradually changing curvature region, and abrupt curvature region based on curvature changes. Specifically, as shown... Figure 2 As shown, a high-precision geometric model of the target radar antenna reflector is first performed. The radar antenna reflector can be any one of a parabolic antenna reflector, a hyperboloid antenna reflector, or a shaped curved antenna reflector. Taking a parabolic antenna reflector with a diameter of 2m as an example, its surface curvature gradually changes from the center vertex to the edge.

[0052] To obtain its precise geometric features, a high-precision 3D laser scanner or structured light scanner is used to acquire the original point cloud data of the antenna reflector. After denoising, registration and fusion processing, the acquired point cloud data is used to obtain a complete and dense 3D point cloud model. Based on this point cloud data, a precise surface mathematical model of the antenna reflector is constructed using non-uniform rational B-spline surface reconstruction technology.

[0053] After obtaining the mathematical model of the surface, surface differential geometry calculations are performed. Specifically, for each discrete local point on the surface, the coefficients of its first and second fundamental forms are calculated, and then the Gaussian curvature (K), mean curvature (H), and two principal radii of curvature at that point are solved. For surfaces such as parabolic or hyperboloid surfaces, the mean radius of curvature R at any point is defined as... This generates a curvature distribution map that comprehensively characterizes the global geometry of the antenna reflector. This map is a matrix associated with the coordinates of the surface model, where each element corresponds to the Gaussian curvature, mean curvature, and principal curvature radius at a specific location on the surface.

[0054] Based on the established curvature map, regions are divided according to the rate of change of the local radius of curvature along its arc length, specifically including:

[0055] Calculate the rate of change of the local radius of curvature along the arc length at each point on the antenna reflector surface, denoted as . Pre-set a threshold When a continuous region on a surface has a local radius of curvature at all points within it that varies per unit arc length, the rate of change of the local radius of curvature is... All are greater than the preset threshold. When this occurs, the region is marked and divided into curvature abrupt change zones, corresponding to the edges of parabolic surfaces, the throats of hyperboloids, or abrupt transitions in shaped surfaces. When a continuous region on a surface has a local radius of curvature change rate at all points within it... When all values ​​are less than or equal to a preset threshold ε, and the local radius of curvature R of all points within the region is greater than a preset flatness threshold, the region is classified as a flat curvature region, located near the vertex of the parabola. All other regions on the surface, except for the curvature abrupt region and the flat curvature region, are automatically classified as gradually changing curvature regions.

[0056] Step S200: Plan the laser sputtering scanning path on the antenna reflector surface, discretize the scanning path into spatially ordered grid nodes, and assign a local radius of curvature and laser incident angle to each grid node.

[0057] After the region is divided, scanning path planning is performed. In a preferred embodiment, as shown in Figure 3, a continuous scanning path covering the entire antenna reflector is generated on the three-dimensional curved surface using the equal arc length projection method or the equal chord height error method. This continuous scanning path is discretized into a series of spatially ordered grid nodes according to the spatial step size. Each grid node... The coordinates in three-dimensional space and their parametric coordinates (u, v) on the surface mathematical model are recorded.

[0058] For each grid node Assign: Local radius of curvature and laser incident angle .

[0059] Local radius of curvature The assignment method is directly taken from the results of the surface differential geometry calculation in step S100, for mesh nodes The average radius of curvature of a point can be directly interpolated in the curvature distribution map using its parameter coordinates (u, v) or directly read, and used as the local radius of curvature of that grid node. .

[0060] laser incident angle The determination method is as follows: First, establish the spatial coordinate system of the LMC laser sputtering system. In this coordinate system, the antenna reflector is fixed on the worktable. For any grid node... The unit normal vector of the surface at that point is calculated using its parametric coordinates (u, v). (Pointing to the outer side of the curved surface), obtain the unit direction vector of the laser beam's central axis. (Pointing to the surface of the antenna reflector), laser incident angle Defined as the spatial angle between the surface normal vector and the incident direction of the laser beam, i.e. Since the normal vector points outwards while the laser beam points inwards, the absolute value of the dot product is taken in the calculation to ensure... The range is between 0° and 90° when the laser beam is incident perfectly perpendicularly. =0°, when the laser beam is tangent to the curved surface =90°.

[0061] In a preferred embodiment, when the laser scanning mechanism is a multi-degree-of-freedom robotic arm, the direction of the central axis of the laser beam... It is variable. To optimize the energy incident angle or avoid interference, the robot arm's posture is dynamically adjusted, causing the laser incident angle of the same mesh node to change at different times or under different scanning strategies. The laser incident angle is dynamically updated based on the real-time spatial relative position relationship. During the sputtering process, the current pose of the robot arm is read in real time and recalculated. and with grid nodes Fixed normal vector The included angle is recalculated to obtain the real-time laser incident angle. And use it for subsequent energy calculations.

[0062] Step S300, based on a pre-built energy-deposition relationship model, calculates the target single-pulse energy and target spot overlap rate required to obtain a uniform coating for each grid node, according to the local radius of curvature and laser incident angle of the grid node. Specifically, this includes:

[0063] A baseline laser sputtering experiment was conducted on a standard planar substrate to determine the process parameters required to obtain a standard coating quality, including obtaining the baseline single-pulse energy. Overlap rate with reference spot The reference spot overlap rate is defined as the percentage of the overlapping area of ​​two adjacent light pulses projected onto the substrate surface to the area of ​​a single spot. It determines the number of pulses received per unit area, thus affecting the deposition rate and thermal effect.

[0064] A series of deposition experiments were conducted by varying the substrate geometry and laser incident angle. Convex and concave substrates with different radii of curvature were prepared. Laser sputtering deposition experiments were performed on each substrate with different laser incident angles. Under each experimental condition, the deposition rate, residual stress of the coating, and microtexture were measured and recorded. A system was established based on the local radius of curvature R and the laser incident angle. Energy compensation coefficient of the independent variable and overlap rate compensation coefficient In a specific example, for a concave surface with a local radius of curvature R = 100 mm, the laser incident angle is... To achieve the same deposition quality as the baseline conditions, the required single-pulse energy needs to be increased to 1.8 times the baseline, and the spot overlap rate needs to be increased to 1.2 times the baseline. Therefore, the definition is... .

[0065] Based on the model constructed above, the energy-deposition relationship model is expressed as: for any grid node i, its target single-pulse energy Overlap rate with target spot The calculation formula is: , ,in, and These are the local radius of curvature and the laser incident angle at the grid node, respectively. For grid nodes located in regions of abrupt curvature change, when the deposition rate falls below the baseline conditions due to a decrease in the local radius of curvature or an increase in the laser incident angle, the energy compensation coefficient... The value is greater than 1, and the overlap rate compensation coefficient is... A value greater than 1 is selected to compensate for the insufficient particle flux and decreased atomic kinetic energy caused by geometric factors by increasing the target single pulse energy and the target spot overlap rate. This dual-parameter synergistic enhancement strategy aims to increase the number of particles and particle kinetic energy of a single pulse by increasing the target single pulse energy, and at the same time increase the total particle flux and heat accumulation effect per unit area by increasing the target spot overlap rate. This accurately compensates for the insufficient particle flux and decreased atomic kinetic energy caused by geometric factors, and ultimately obtains a coating of the same quality as the flat area in the curvature abrupt change region.

[0066] In step S400, during the LMC laser sputtering process, the grid node currently being acted upon by the laser is acquired in real time. The laser pulse energy is instantaneously adjusted to the target single pulse energy corresponding to the grid node through an acousto-optic modulator and a pulse power supply. At least one of the scanning speed and the laser pulse repetition frequency is adjusted to make the actual spot overlap rate reach the target spot overlap rate corresponding to the grid node.

[0067] Before starting sputtering, calculate the target process parameters for all mesh nodes. , The data is loaded into memory and associated with the spatial coordinates and sequence number of each grid node. The current position feedback of the laser scanning motion mechanism is read in real time to determine the grid node currently acting on by the laser spot, denoted as node i. Two-step control is then performed:

[0068] Instantaneous adjustment of laser pulse energy: The control system adjusts the target single pulse energy at node i. Control commands are sent to the acousto-optic modulator (AOM) or pulse power supply inside the LMC laser. The acousto-optic modulator can quickly change its diffraction efficiency by changing the power of the driving radio frequency signal, thereby achieving the attenuation or enhancement of the output laser pulse energy. The pulse power supply can regulate the pulse energy by directly changing the discharge voltage or current, ensuring that each spot can obtain the required energy even under high-speed scanning.

[0069] Real-time control of actual spot overlap rate: In LMC laser sputtering, the spot overlap rate O is determined by the scanning speed v, the laser pulse repetition frequency f, and the spot diameter d, and their relationship is as follows: ,in, For the grid node The overlap rate of the target light spot at that location. For the laser beam at the grid node Scanning speed at that location The diameter of the laser spot formed by the laser beam on the surface of the antenna reflector is given. Regarding the laser pulse repetition frequency, in a preferred embodiment, a strategy of variable scanning speed and constant pulse frequency is adopted. For example, the laser pulse repetition frequency f is kept constant at 10kHz, and the spot diameter d is 0.1mm. In the flat curvature region, the target spot overlap rate is... The required scanning speed can be calculated by working backward from the formula. mm / s, when scanning to the curvature abrupt change region, the target spot overlap rate increases to The required scanning speed then drops to mm / s, by adjusting the moving speed of the scanning motion mechanism in real time, it can accurately follow the corresponding node. This allows for the acquisition of the desired overlap rate. In another embodiment, a constant-speed frequency conversion strategy is employed to maintain a constant scanning speed. By controlling the trigger signal of the acousto-optic modulator or laser, the laser pulse repetition frequency f is adjusted in real time to achieve precise control of the overlap rate.

[0070] Step S500 continues to execute S400 until all grid nodes have been deposited, forming a coating with uniform thickness, residual stress, and microtexture on the antenna reflector surface. The scanning process is continuously monitored, and step S400 is repeated; that is, each time a new grid node is moved, the preset parameters for that node are updated. and Adjust the laser energy and scanning speed / frequency. The scanning process ends when the last grid node has completed deposition. A coating with highly uniform thickness, residual stress, and microtexture is formed on the antenna reflector surface.

[0071] In a preferred embodiment, to improve resource utilization efficiency and response speed, a hierarchical control strategy is introduced. This strategy differentiates the control parameters of the acousto-optic modulator and the scanning motion mechanism based on the geometric complexity of the three regions (curvature abrupt change region, gradual change region, and flat region) divided in step S100. For mesh nodes located in the curvature abrupt change region, due to the drastic changes in geometric features in this region, the requirements for energy and overlap rate compensation are high and change rapidly. The single-pulse energy adjustment step size of the acousto-optic modulator is set to the first step size precision. For example, the output precision of the DAC (digital-to-analog converter) is set to 12 bits, so that the minimum resolution of energy adjustment is 0.1mJ. At the same time, the update frequency of the servo response frequency and / or the laser pulse repetition frequency of the scanning motion mechanism is set to the first response frequency. For example, the response frequencies of the position loop and the current loop are increased to 4kHz to ensure rapid response to abrupt changes in curvature.

[0072] When the curvature is gradually varied, the geometric parameters change smoothly. The energy adjustment step size is set to 10-bit precision, the resolution is 0.5mJ, and the response frequency is set to 2kHz.

[0073] When the region is identified as a flat curvature region, the geometric parameters remain essentially unchanged. In order to reduce computation and motion energy consumption, the single-pulse energy adjustment step size of the acousto-optic modulator is set to the second step size accuracy. For example, the DAC accuracy is set to 8 bits with a resolution of 2mJ. At the same time, the response frequency of the scanning motion mechanism and / or the laser pulse repetition frequency is set to the second response frequency of 1kHz.

[0074] With the above configuration, the first step length accuracy is less than the second step length accuracy (0.1mJ < 2mJ), and the first response frequency is greater than the second response frequency (4kHz > 1kHz). This results in a higher energy regulation resolution and faster dynamic response speed in the curvature abrupt region compared to the curvature flat region, ensuring optimal performance in the region where precise control is most needed.

[0075] Based on any of the above embodiments, the method of the present invention is applicable to a variety of coating materials. Preferably, the coating material is any one of the following metals: high-purity gold (Au, purity ≥ 99.99%), high-purity silver (Ag, purity ≥ 99.99%), and high-purity aluminum (Al, purity ≥ 99.99%). LMC laser sputtering technology can maintain the stoichiometry of the target material and is suitable for preparing high-purity metal thin films.

[0076] In another embodiment, the coating material can also be a dielectric material, such as aluminum oxide. silicon oxide Or strontium titanate (BST), etc.

[0077] In summary, this invention provides a method for coating radar antenna reflectors with LMC laser sputtering energy modulation. By first modeling and partitioning the spectrum, and then discretizing and assigning parameters to the path, the complex surface geometry is transformed into quantifiable and programmable laser process parameters, thereby achieving precise control over the entire domain of coating thickness, residual stress, and microtexture.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation, characterized in that, The steps of this method are as follows: S100. Establish a high-precision three-dimensional curvature map of the antenna reflector and divide the antenna reflector into a flat curvature region, a gradually changing curvature region, and a sudden curvature region based on the curvature change. S200. Plan a laser sputtering scanning path on the antenna reflector surface, discretize the scanning path into spatially ordered grid nodes, and assign a local radius of curvature and laser incident angle to each grid node. S300. Based on a pre-built energy-deposition relationship model, for each grid node, the target single-pulse energy and target spot overlap rate required to obtain a uniform coating are calculated according to the local radius of curvature and laser incident angle of the grid node. S400. During LMC laser sputtering, the grid node currently being acted upon by the laser is acquired in real time. The laser pulse energy is adjusted to the target single pulse energy corresponding to the grid node through an acousto-optic modulator and a pulse power supply. At least one of the scanning speed and the laser pulse repetition frequency is adjusted to make the actual spot overlap rate reach the target spot overlap rate corresponding to the grid node. S500, continue executing S400 until all grid nodes are deposited, forming a coating of uniform thickness and height on the antenna reflector surface.

2. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, In S100, the method for dividing the curvature abrupt change region, the curvature gradual change region, and the curvature flat region is as follows: Calculate the rate of change of the local radius of curvature along the arc length at each point on the antenna reflector surface. When the rate of change of the local radius of curvature in any region on the surface within a unit arc length is greater than a preset threshold, the region is regarded as a curvature abrupt change region. When the rate of change is less than or equal to the preset threshold and the local radius of curvature of the region is greater than the first preset value, the region is designated as a curvature flat region. The region on the surface other than the curvature abrupt region and the curvature flat region is defined as the curvature gradual change region.

3. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, In S100, the high-precision three-dimensional curvature map includes: Obtain point cloud data of the antenna reflector and reconstruct a surface mathematical model of the antenna reflector based on the point cloud data; The surface mathematical model is subjected to surface differential geometry calculations to obtain the Gaussian curvature, mean curvature, and principal curvature radius at each local point on the surface, forming a curvature distribution map that characterizes the global geometric features of the antenna reflector.

4. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, In S200, the laser incident angle is determined as follows: In the spatial coordinate system of the LMC laser sputtering system, the surface normal vector of the grid node is taken as the reference direction, and the unit direction vector of the laser beam central axis is taken as the incident direction. The spatial angle between the surface normal vector and the unit direction vector of the laser beam central axis is calculated, and the spatial angle is taken as the laser incident angle of the grid node. For the same grid node, when the spatial relative position of the surface normal vector and the laser beam central axis changes due to the posture adjustment of the scanning motion mechanism, the laser incident angle is dynamically updated according to the real-time spatial relative position relationship. In S200, the local radius of curvature assigned to the mesh node is the average radius of curvature at the mesh node calculated by surface differential geometry.

5. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, In S300, the construction process of the energy-deposition relationship model is as follows: Laser sputtering experiments were conducted on a planar substrate with a laser incident angle of zero degrees to determine the reference single-pulse energy required to obtain a standard coating quality. Overlap rate with reference spot ; A series of deposition experiments were conducted by varying the substrate radius of curvature and the laser incident angle. The deposition rate and film properties under different conditions were measured, and a system based on the local radius of curvature was established. and laser incident angle Energy compensation coefficient of the independent variable and overlap rate compensation coefficient ; The energy-deposition relationship model is expressed as follows: , For any grid node The grid node Target single pulse energy The grid node Target spot overlap rate ,in, For the grid node The local radius of curvature, For the grid node The laser incident angle.

6. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, In step S400, when adjusting the scanning speed and laser pulse repetition frequency, according to... To implement control, among which... For the grid node The overlap rate of the target light spot at that location. For the laser beam at the grid node Scanning speed at that location The diameter of the laser spot formed by the laser beam on the surface of the antenna reflector is given. The laser pulse repetition frequency is adjusted in real time. and At least one parameter in the equation, such that Established.

7. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, The S400 also includes a tiered control strategy: For mesh nodes located in the curvature abrupt change region, the single pulse energy adjustment step size of the acousto-optic modulator is set to the first step length precision, and the response frequency of the scanning motion mechanism and / or laser pulse repetition frequency is set to the first response frequency; When the curvature is flat, the single pulse energy adjustment step size of the acousto-optic modulator is set to the second step size accuracy, and the response frequency of the scanning motion mechanism and / or the laser pulse repetition frequency is set to the second response frequency. The first step length accuracy is less than the second step length accuracy, and the first response frequency is greater than the second response frequency.

8. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, The coating material is any one of the following metals: high-purity gold, high-purity silver, and high-purity aluminum, or a dielectric material.

9. The method for coating a radar antenna reflector surface using LMC laser sputtering energy modulation according to claim 1, characterized in that, The radar antenna reflector can be any one of a parabolic antenna reflector, a hyperboloid antenna reflector, or a shaped curved surface antenna reflector.

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