Micro-cone array femtosecond laser processing method and system based on annular spot modulation

Abstract

The present invention provides a femtosecond laser processing method and system for micro-cone arrays based on annular spot modulation, including a beam shaping module, a focusing module, a motion module, a visual calibration module, a focus measurement module and a synchronous triggering module. The beam shaping module provides multiple beams of parallel modulated lasers, which are focused into an annular focused laser beam by the focusing module. The annular focused laser beam processes the micro-cone array blank on the motion module. The visual calibration module calibrates the focusing position of the annular focused laser beam and monitors the laser processing process in real time. The focus measurement module constructs the three-dimensional morphology of the micro-cone array blank. The synchronous triggering module forms the control timing of the beam shaping module and the motion module according to the three-dimensional morphology of the micro-cone array blank. The present invention can take into account the processing accuracy and efficiency requirements of large-scale micron-level micro-cone arrays at the same time through the combination of precise focusing of the objective lens and parallel processing of multiple beams.

Description

Technical Field

[0001] The present invention relates to the technical field of femtosecond laser processing, and in particular to a micro-cone array femtosecond laser processing method and system based on annular spot modulation. Background Art

[0002] Ionic liquid electrospray thrusters are a new generation of electric thrusters suitable for microsatellite propulsion. They use a conductive liquid as a propellant and utilize an electrostatic field to extract and eject charged droplets / ions from the propellant to generate thrust. The emitter, typically a micro-conical array, is a key component in the thrust, efficiency, and specific impulse of ionic liquid electrospray thrusters. The emitter micro-conical array has the following requirements for accuracy, scale, and materials:

[0003] First, precision requirements. The geometric accuracy of the emitter microcone has a significant impact on the overall performance of the ionic liquid electrospray thruster. For example, the microcone tip curvature radius (generally in the μm range), the microcone aspect ratio (generally greater than 2), and the geometric repeatability of the microcone array all directly affect the thruster's inter-electrode voltage and propellant flow impedance, thereby affecting the efficiency and service life of the electrospray thruster.

[0004] Second, the scale requirement. The thrust generated by a single micro-cone emitter cannot meet the requirements of actual space missions, so it is necessary to use a micro-cone array to increase the total ion emission current and thus increase the thrust (the emitter array scale can reach ~1000 / cm 2 ).

[0005] Third, material requirements. Considering that the corrosion of ionic liquids on traditional corrosion-resistant micro-cone materials such as metals will reduce the service life of the emitter, the emitter material of the new generation of electrospray thrusters is made of corrosion-resistant porous glass or ceramics.

[0006] The high precision and large scale of emitter microcone arrays, coupled with the hard and brittle nature of the materials, require processing techniques that are precise, efficient, and highly adaptable to materials. Femtosecond lasers, on the other hand, are ultrafast (short pulse width), ultrastrong (high peak power), ultrafine (high processing accuracy), and highly adaptable to materials (capable of processing hard-to-cut materials such as brittle, hard, and thin materials). The resulting nonlinear femtosecond laser manufacturing technology can overcome the limitations of traditional micro-nano manufacturing, enabling efficient and precise manufacturing of complex three-dimensional structures with processing accuracy ranging from submicron to nanometer levels.

[0007] Among the current laser processing patents, patent application number CN201811489271.2 discloses a method for preparing a highly uniform micro-cone array structure. Based on a femtosecond laser direct writing processing system and a high-speed scanning galvanometer system, the method can quickly prepare a large-area micro-cone array structure by setting a specific scanning path, and can adjust the morphological parameters of the micro-cone structure by parameters such as the distance between the laser focus and the material, the energy of a single pulse, the scanning speed, and the scanning interval. Although the high-speed scanning galvanometer system used in this patent fully utilizes the ultrafast processing characteristics of the femtosecond laser, the field mirror spot focus size used in the high-speed scanning galvanometer system is generally greater than 5μm, and its processing resolution cannot meet the processing requirements of micro-cones with a micron-level tip curvature radius.

[0008] There are currently two methods to ensure the processing resolution of femtosecond laser processing of array structures:

[0009] One is the focused laser three-dimensional processing based on the five-axis linkage motion platform. All interpolation points on the processing path are positioned by the five-axis linkage platform to ensure that the optical axis of the incident laser beam is always perpendicular to the surface of the processed curved surface, so it has higher processing accuracy. For example, the patent with application number CN202011341359.2 discloses a dual-probe five-axis linkage laser processing machine tool and a working method. The technical points are: bed, X-axis moving mechanism, Y-axis moving mechanism, Z-axis moving mechanism, A-axis rotation mechanism, B-axis rotation mechanism, C-axis rotation mechanism, laser optical path device, adapter plate, laser head. However, this design of single-beam laser focusing combined with five-axis linkage has the disadvantages of complex interpolation motion planning and frequent startup, which makes it impossible to take into account processing efficiency while ensuring accuracy.

[0010] The second is focused laser three-dimensional processing based on time / space / frequency shaping, which improves the quality of the laser beam through shaping in the time domain / spatial light / frequency domain, ensuring the optimal laser time / space / frequency parameters that match the processing material, thereby improving the processing accuracy. For example, the Chinese patent application number CN201910299942.7 discloses a system for processing array microholes of femtosecond laser based on spatial beam shaping. It uses a spatial light modulator SLM to shape a single beam of femtosecond laser into a multi-beam array light field with a specific spatial distribution by designing different phases, adjusts the laser repetition frequency, laser beam waist radius, and laser pulse energy, and finally focuses the shaped femtosecond laser onto the sample surface through the processing objective lens, thereby achieving high-quality, large-area array microhole processing on a variety of materials. The processing objective lens focusing scheme adopted in this patent can give full play to the ultra-fine processing characteristics of the femtosecond laser, and the focusing resolution meets the processing requirements of the micro-cone array. The multi-beam array processing scheme based on spatial beam shaping also has higher processing efficiency than single-beam focusing. However, its single processing fixes the spot shape and size, which is only suitable for the two-dimensional morphology of micropores, and cannot process the quasi-three-dimensional morphology of microcones.

[0011] Existing femtosecond laser processing methods have problems such as being unable to balance the requirements of efficiency and precision, and the multi-beam array processing used is not suitable for the variable diameter morphology characteristics of micro-cone arrays.

[0012] Therefore, there is an urgent need for a femtosecond laser processing method and system for micro-cone arrays that is both efficient and precise and suitable for processing variable diameter morphological features. Summary of the Invention

[0013] In view of the defects in the prior art, the purpose of the present invention is to provide a micro-cone array femtosecond laser processing method and system based on annular spot modulation.

[0014] According to the present invention, a 3D cone array femtosecond laser processing system based on annular spot modulation is provided, which includes a beam shaping module, a focusing module, a motion module, a visual calibration module, a focus measurement module and a synchronous trigger module;

[0015] The beam shaping module provides multiple parallel modulated laser beams (7), the multiple parallel modulated laser beams (7) are focused into an annular focused laser beam (9) by a focusing module, and the annular focused laser beam (9) processes a micro-cone array blank (10) on the motion module;

[0016] The visual calibration module calibrates the focus position of the annular focused laser beam (9) and monitors the laser processing process in real time, and the focus measurement module constructs the three-dimensional morphology of the micro-cone array blank (10);

[0017] The synchronous trigger module forms a control sequence of the beam shaping module and the motion module according to the three-dimensional appearance of the micro-cone array blank (10).

[0018] Preferably, the beam shaping module comprises: a femtosecond laser (1) emits laser pulses, which are modulated into multiple beams of parallel modulated laser light (7) via a beam expander (2), a spatial light shaper (3), a first total reflection mirror (4), a dispersion compensation system (5) and a second total reflection mirror (6).

[0019] Preferably, the focusing module comprises: multiple parallel modulated laser beams (7) are focused into an annular focused laser beam (9) via an objective lens (8) for processing a micro-cone array blank (10);

[0020] The motion module comprises a three-dimensional motion platform (13) supporting a micro-cone array blank (10) and being used for regulating the position of the micro-cone array blank (10) relative to a circular focused laser beam (9).

[0021] Preferably, the visual calibration module comprises: imaging light emitted by an LED light source (18) is irradiated onto the surface of a complex three-dimensional component along the reflection of two dichroic beam splitters (17), and a CCD camera (19) is then exposed and imaged, and etching features of a micro-cone array blank (10) are imaged based on an annular focused laser beam (9), and the focusing position of the annular focused laser beam (9) is calibrated and the laser processing process is monitored in real time.

[0022] Preferably, the focus measurement module comprises: light emitted by a coaxial light source of a double telecentric lens (18) is reflected by the surface of the micro-cone array blank (10), and then imaged on a sensor of a high-resolution camera (17) through the double telecentric lens (18); the focus measurement module moves longitudinally relative to the measured cone surface; and through digital image processing, the definition change state of the image collected during the displacement process is analyzed to achieve the three-dimensional morphology construction of the micro-cone array blank (10).

[0023] Preferably, the synchronous trigger module includes: a synchronous trigger (19) connected to the beam shaping module and the motion module to synchronize the control timing of laser light emission, laser modulation and displacement stage movement.

[0024] According to a micro-cone array femtosecond laser processing method based on annular spot modulation provided by the present invention, the following steps are performed using the micro-cone array femtosecond laser processing system based on annular spot modulation;

[0025] Step S1: The focus measurement module constructs the micro-cone three-dimensional morphology of the micro-cone array blank (10);

[0026] Step S2: planning the processing technology of the micro-cone target morphology according to the micro-cone three-dimensional morphology, and formulating the control program of the spatial light modulator (3) and the beam shaping module and motion module of the three-dimensional motion platform (13) for laser processing;

[0027] Step S3: Based on the visual calibration module, focusing of the focusing module and the moving annular focusing laser beam (9) and zeroing operation of the three-dimensional motion platform (13) are realized;

[0028] Step S4: The synchronous trigger module (19) synchronously controls the light output of the femtosecond laser (1) of the beam shaping module and the motion module, the modulation of the spatial light modulator (3) and the start of the three-dimensional motion platform (13), and starts processing;

[0029] Step S5: After a single processing is completed, the focus measurement module reconstructs the three-dimensional morphology of the processed micro-cone array (11) and counts the size and shape features, and determines whether the three-dimensional morphology of the currently processed micro-cone array (11) meets the expected requirements. If so, the processing is terminated; if not, the process returns to step S2.

[0030] Preferably, the step S1 includes:

[0031] Step S1.1: The three-dimensional motion platform (13) moves the micro-cone array into the field of view of the bi-telecentric lens (18);

[0032] Step S1.2: The high-resolution camera (17) exposes the micro-cone array cross-sectional object image in the focal plane through the bi-telecentric lens (18);

[0033] Step S1.3: The three-dimensional motion platform (13) controls the up and down movement of the micro-cone array to realize imaging acquisition of different longitudinal sections of the micro-cone array;

[0034] Step S1.4: Through contour recognition and digital image processing, different cross-sectional images are spliced ​​to achieve the three-dimensional morphology construction of the micro-cone array.

[0035] Preferably, step S2 includes:

[0036] Step S2.1: determining the optimal processing path of the annular focused laser beam (9) and the shape change curve of the annular focused laser beam (9) based on the three-dimensional morphology of the micro-cone array;

[0037] Step S2.2: determining the motion curve of the three-dimensional motion platform (13) based on the three-dimensional morphology of the micro-cone array and the laser processing path;

[0038] Step S2.3: According to the optimal processing path of the annular focused laser beam (9), the shape change curve of the annular focused laser beam (9), and the motion curve of the three-dimensional motion platform (13), the shaping control program of the spatial modulator (3) and the linkage control program of the three-dimensional motion platform (13) are set.

[0039] Preferably, before the processing begins, a visual calibration module is used as a laser focus positioning device, and based on the annular focused laser beam (9), the etching features of the micro-cone array blank (10) are imaged to determine the focal plane of the objective lens (8), and the three-dimensional motion platform (13) is controlled to move the top surface of the unprocessed micro-cone array to the focal plane of the objective lens (8), thereby ensuring that the annular focused laser beam (9) performs etching processing from top to bottom.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention combines precise focusing of the objective lens with multi-beam parallel processing, which can simultaneously take into account the processing accuracy and efficiency requirements of large-scale micron-level micro-cone arrays.

[0042] 2. The present invention can more efficiently realize the precise processing of variable diameter morphological features of large-scale micron-scale micro-cone arrays through real-time size modulation of the annular spot.

[0043] 3. The present invention realizes the integration of measurement and processing by combining the focus measurement method with femtosecond laser processing, which helps to ensure that the shape and position accuracy of the micro-cone meets the index requirements.

[0044] 4. The present invention uses a visual calibration module to assist laser focusing and platform movement, realizing intelligent laser focusing and workpiece positioning, which helps to further improve the processing efficiency of the micro-cone array. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0046] Figure 1 Schematic diagram of the micro-cone array femtosecond laser processing system based on annular spot modulation in the present invention.

[0047] Figure 2 This is a flow chart of the femtosecond laser processing method of micro-cone array based on annular spot modulation in the present invention.

[0048] Figure 3 Schematic diagram of constructing micro-cone three-dimensional morphology based on focus measurement in the present invention.

[0049] Figure 4 Schematic diagram of processing path planning based on the change of annular spot size in the present invention.

[0050] In the figure: 1- femtosecond laser; 2- beam expander; 3- spatial light modulator; 4- first total reflection mirror; 5- dispersion compensation system; 6- second total reflection mirror; 7- multi-beam parallel modulated laser; 8- objective lens; 9- annular focused laser beam; 10- micro-cone array blank; 11- processed micro-cone array; 12- unprocessed micro-cone array; 13- three-dimensional motion platform; 14- dichroic beam splitter; 15- LED light source; 16- CCD camera; 17- high-resolution camera; 18- double telecentric lens; 19- synchronization trigger. DETAILED DESCRIPTION

[0051] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0052] The present invention can take into account both efficient processing and precise processing, and ensure the shape and position accuracy of the micro-cone array through the integration of measurement and processing to meet the corresponding aerospace application requirements.

[0053] Example 1

[0054] According to the present invention, a 3D cone array femtosecond laser processing system based on annular spot modulation is provided. Figure 1 As shown, the system includes a beam shaping module, a focusing module, a motion module, a visual calibration module, a focus measurement module, and a synchronous triggering module. The beam shaping module provides multiple parallel modulated laser beams 7, which are focused into an annular focused laser beam 9 by the focusing module. The annular focused laser beam 9 processes the micro-cone array blank 10 on the motion module. The visual calibration module calibrates the focus position of the annular focused laser beam 9 and monitors the laser processing process in real time. The focus measurement module constructs the three-dimensional topography of the micro-cone array blank 10. The synchronous triggering module determines the control timing of the beam shaping module and the motion module based on the three-dimensional topography of the micro-cone array blank 10.

[0055] Specifically, the beam shaping module includes: a femtosecond laser 1 emits laser pulses, which are modulated into multiple beams of parallel modulated laser light 7 by a beam expander 2, a spatial light shaper 3, a first total reflection mirror 4, a dispersion compensation system 5 and a second total reflection mirror 6.

[0056] The focusing module includes multiple parallel modulated laser beams 7 that are focused by an objective lens 8 into a circular focused laser beam 9 for processing a micro-cone array blank 10. The motion module includes a three-dimensional motion platform 13 that supports the micro-cone array blank 10 and is used to adjust the position of the micro-cone array blank 10 relative to the circular focused laser beam 9.

[0057] The visual calibration module includes: the imaging light emitted by the LED light source 18 is irradiated onto the surface of the complex three-dimensional component along the reflection of two dichroic mirrors 17, and the CCD camera 19 then exposes and images the surface. The etching features of the micro-cone array blank 10 are imaged based on the annular focused laser beam 9, the focusing position of the annular focused laser beam 9 is calibrated, and the laser processing process is monitored in real time.

[0058] The focus measurement module includes: the light emitted by the coaxial light source of the double telecentric lens 18 is reflected by the surface of the micro-cone array blank 10, and then imaged on the sensor of the high-resolution camera 17 through the double telecentric lens 18. The focus measurement module moves longitudinally relative to the measured cone surface, and through digital image processing, the change state of the image clarity collected during the displacement process is analyzed to realize the three-dimensional morphology construction of the micro-cone array blank 10.

[0059] The synchronous trigger module includes: a synchronous trigger 19 connected to the beam shaping module and the motion module to synchronize the control timing of laser emission, laser modulation and translation stage movement.

[0060] The present invention combines precise focusing of an objective lens with parallel processing of multiple beams, thereby being able to simultaneously meet the processing accuracy and efficiency requirements of large-scale micron-level micro-cone arrays.

[0061] Example 2

[0062] The focus measurement module of the present invention constructs the three-dimensional morphology of the micro-cone array blank. According to the three-dimensional morphology of the micro-cone, the processing technology of the target morphology is planned, and the control program of the spatial light modulator and the three-dimensional motion platform is formulated. Based on the visual calibration module, the focusing of the annular focused laser beam and the return to zero of the three-dimensional motion platform are realized. The synchronous trigger controls the light output of the femtosecond laser, the adjustment of the spatial light modulator and the start of the three-dimensional motion platform to start the processing. After the single processing is completed, the focus measurement module reconstructs the three-dimensional morphology of the micro-cone array. If the three-dimensional morphology of the micro-cone array does not meet the expected requirements, repeat the above steps; if the three-dimensional morphology of the micro-cone array meets the expected requirements, the processing is terminated.

[0063] According to the present invention, a femtosecond laser processing method for a micro-cone array based on annular spot modulation is provided. Figures 2 to 4 As shown, the micro-cone array femtosecond laser processing system based on annular spot modulation performs the following steps;

[0064] Step S1: The focus measurement module constructs the micro-cone three-dimensional morphology of the micro-cone array blank 10. Specifically, Figure 3 As shown, step S1 includes: Step S1.1: The three-dimensional motion platform 13 moves the micro-cone array into the field of view of the bi-telecentric lens 18. Step S1.2: The high-resolution camera 17 uses the bi-telecentric lens 18 to expose a cross-sectional image of the micro-cone array in the focal plane. Step S1.3: The three-dimensional motion platform 13 controls the up and down movement of the micro-cone array to capture images of different longitudinal cross-sections of the micro-cone array. Step S1.4: Through contour recognition and digital image processing, the different cross-sectional images are stitched together to construct the three-dimensional topography of the micro-cone array.

[0065] Step S2: Based on the three-dimensional morphology of the micro-cone, plan the processing technology of the micro-cone target morphology, and formulate the control program of the spatial light modulator 3 and the beam shaping module and motion module of the three-dimensional motion platform 13 for laser processing. Specifically, step S2 includes: Step S2.1: Based on the three-dimensional morphology of the micro-cone array, determine the optimal processing path of the annular focused laser beam 9 and the shape change curve of the annular focused laser beam 9. Step S2.2: Based on the three-dimensional morphology of the micro-cone array and the laser processing path, determine the motion curve of the three-dimensional motion platform 13. Step S2.3: According to the optimal processing path of the annular focused laser beam 9 and the shape change curve of the annular focused laser beam 9, and the motion curve of the three-dimensional motion platform 13, set the shaping control program of the spatial modulator 3 and the linkage control program of the three-dimensional motion platform 13.

[0066] Step S3: Based on the visual calibration module, the focusing module and the moving annular focused laser beam 9 and the zero return operation of the three-dimensional motion platform 13 are realized.

[0067] Step S4: Synchronous trigger module Synchronous trigger 19 synchronously controls the light emission of femtosecond laser 1 of beam shaping module and motion module, the modulation of spatial light modulator 3 and the start of three-dimensional motion platform 13 to start processing.

[0068] Step S5: After a single processing is completed, the focus measurement module reconstructs the three-dimensional morphology of the processed micro-cone array 11 and counts the size and shape characteristics, and determines whether the three-dimensional morphology of the current processed micro-cone array 11 meets the expected requirements. If so, the processing is terminated; if not, the process returns to step S2.

[0069] Furthermore, before the processing begins, a visual calibration module is used as a laser focus positioning device. Based on the annular focused laser beam 9, the etching features of the micro-cone array blank 10 are imaged to determine the focal plane of the objective lens 8, and the three-dimensional motion platform 13 is controlled to move the top surface of the unprocessed micro-cone array to the focal plane of the objective lens 8 to ensure that the annular focused laser beam 9 is used for etching from top to bottom.

[0070] The present invention aims to achieve both high efficiency and precision machining requirements for large-scale micron-scale micro-cone arrays through multi-beam parallel processing and precise focusing of the objective lens. By integrating detection and processing, it can compensate for finishing errors in real time, which helps to further improve the machining accuracy of the micro-cone array.

[0071] The present invention uses real-time size modulation of the annular spot to more efficiently achieve precise processing of variable-diameter morphological features of large-scale micron-level micro-cone arrays. By combining the focus measurement method with femtosecond laser processing, measurement and processing are integrated, which helps to ensure that the shape and position accuracy of the micro-cones meet the index requirements. The present invention uses a visual calibration module to assist laser focusing and platform movement, realizing intelligent laser focusing and workpiece positioning, which helps to further improve the processing efficiency of the micro-cone array.

[0072] Those skilled in the art will appreciate that, in addition to implementing the system, device, and various modules provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, and the like by logically programming the method steps. Therefore, the system, device, and various modules provided by the present invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; the modules for implementing various functions can also be considered both software programs for implementing the method and structures within the hardware component.

[0073] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A femtosecond laser processing method for micro-cone arrays based on annular spot modulation, characterized in that: The following steps are performed using a micro-cone array femtosecond laser processing system based on annular spot modulation; Step S1: The focus measurement module constructs the micro-cone three-dimensional morphology of the micro-cone array blank (10); Step S2: planning the processing technology of the micro-cone target morphology according to the micro-cone three-dimensional morphology, and formulating the control program of the spatial light modulator (3) and the beam shaping module and motion module of the three-dimensional motion platform (13) for laser processing; Step S3: Based on the visual calibration module, focusing of the focusing module and the moving annular focusing laser beam (9) and zeroing operation of the three-dimensional motion platform (13) are realized; Step S4: The synchronous trigger module (19) synchronously controls the light output of the femtosecond laser (1) of the beam shaping module and the motion module, the modulation of the spatial light modulator (3) and the start of the three-dimensional motion platform (13), and starts processing; Step S5: After a single processing is completed, the focus measurement module reconstructs the three-dimensional morphology of the processed micro-cone array (11) and counts the size and shape characteristics, and determines whether the three-dimensional morphology of the currently processed micro-cone array (11) meets the expected requirements. If so, the processing is terminated; if not, the process returns to step S2; The 3D cone array femtosecond laser processing system based on annular spot modulation includes a beam shaping module, a focusing module, a motion module, a visual calibration module, a focus measurement module and a synchronous trigger module; The beam shaping module provides multiple parallel modulated laser beams (7), the multiple parallel modulated laser beams (7) are focused into an annular focused laser beam (9) by a focusing module, and the annular focused laser beam (9) processes a micro-cone array blank (10) on the motion module; The visual calibration module calibrates the focus position of the annular focused laser beam (9) and monitors the laser processing process in real time, and the focus measurement module constructs the three-dimensional morphology of the micro-cone array blank (10); The synchronous trigger module forms a control sequence of the beam shaping module and the motion module according to the three-dimensional appearance of the micro-cone array blank (10).

2. The femtosecond laser processing method of a 3D cone array based on annular spot modulation according to claim 1, characterized in that: The beam shaping module comprises: a femtosecond laser (1) emits laser pulses, which are modulated into multiple beams of parallel modulated laser light (7) via a beam expander (2), a spatial light modulator (3), a first total reflection mirror (4), a dispersion compensation system (5) and a second total reflection mirror (6).

3. The femtosecond laser processing method of a 3D cone array based on annular spot modulation according to claim 1, characterized in that: The focusing module comprises: multiple beams of parallel modulated laser light (7) are focused into an annular focused laser beam (9) via an objective lens (8) for processing a micro-cone array blank (10); The motion module comprises a three-dimensional motion platform (13) supporting a micro-cone array blank (10) and being used for regulating the position of the micro-cone array blank (10) relative to a circular focused laser beam (9).

4. The femtosecond laser processing method of a 3D cone array based on annular spot modulation according to claim 1, characterized in that: The visual calibration module includes: imaging light emitted by an LED light source (15) is irradiated onto the surface of a complex three-dimensional component along the reflection of two dichroic beam splitters (14), and a CCD camera (16) is then exposed and imaged, and etching features of a micro-cone array blank (10) are imaged based on an annular focused laser beam (9), and the focusing position of the annular focused laser beam (9) is calibrated and the laser processing process is monitored in real time.

5. The femtosecond laser processing method of a 3D cone array based on annular spot modulation according to claim 1, characterized in that: The focus measurement module comprises: light emitted by a coaxial light source of a double telecentric lens (18) is reflected by the surface of a micro-cone array blank (10), and then formed into an image on a sensor of a high-resolution camera (17) through the double telecentric lens (18); the focus measurement module moves longitudinally relative to the measured cone surface; and through digital image processing, the definition change state of the image collected during the displacement process is analyzed to achieve the three-dimensional morphology construction of the micro-cone array blank (10).

6. The femtosecond laser processing method of a 3D cone array based on annular spot modulation according to claim 1, characterized in that: The synchronous trigger module comprises a synchronous trigger (19) connected with the beam shaping module and the motion module to synchronize the control timing of laser light emission, laser modulation and displacement stage movement.

7. The femtosecond laser processing method for micro-cone arrays based on annular spot modulation according to claim 1, characterized in that: The step S1 comprises: Step S1.1: The three-dimensional motion platform (13) moves the micro-cone array into the field of view of the bi-telecentric lens (18); Step S1.2: The high-resolution camera (17) exposes the micro-cone array cross-sectional object image in the focal plane through the bi-telecentric lens (18); Step S1.3: The three-dimensional motion platform (13) controls the up and down movement of the micro-cone array to realize imaging acquisition of different longitudinal sections of the micro-cone array; Step S1.4: Through contour recognition and digital image processing, different cross-sectional images are spliced ​​to achieve the three-dimensional morphology construction of the micro-cone array.

8. The femtosecond laser processing method for micro-cone arrays based on annular spot modulation according to claim 1, characterized in that: The step S2 comprises: Step S2.1: determining the optimal processing path of the annular focused laser beam (9) and the shape change curve of the annular focused laser beam (9) based on the three-dimensional morphology of the micro-cone array; Step S2.2: determining the motion curve of the three-dimensional motion platform (13) based on the three-dimensional morphology of the micro-cone array and the laser processing path; Step S2.3: According to the optimal processing path of the annular focused laser beam (9), the shape change curve of the annular focused laser beam (9), and the motion curve of the three-dimensional motion platform (13), the shaping control program of the spatial light modulator (3) and the linkage control program of the three-dimensional motion platform (13) are set.

9. The femtosecond laser processing method for micro-cone arrays based on annular spot modulation according to claim 1, characterized in that: Before the start of processing, a visual calibration module is used as a laser focus positioning device to image the etching features of the micro-cone array blank (10) based on the annular focused laser beam (9), determine the focal plane of the objective lens (8), and control the three-dimensional motion platform (13) to move the top surface of the unprocessed micro-cone array to the focal plane of the objective lens (8), ensuring that the annular focused laser beam (9) is used for etching processing from top to bottom.

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