A femtosecond laser micro-nano machining device based on dynamic focusing

Abstract

This invention relates to the field of femtosecond laser application technology, specifically to a femtosecond laser micro / nano fabrication device based on dynamic focusing. It includes a processing stage for mounting the workpiece and a drive mechanism that moves along a processing trajectory. A laser for generating femtosecond laser pulses is positioned above the processing stage. A rotation module and a beam-shrinking mechanism are sequentially arranged along the irradiation direction of the femtosecond laser pulses. The rotation module includes a first optical path system for irradiating along the processing trajectory and a second optical path system for probing the workpiece. The beam-shrinking mechanism is used to adjust the beam diameter and to generate polarized light with different polarization states. A CCD camera for acquiring real-time image data is also included. A control module is further included, which adjusts the power of the beam-shrinking mechanism and the laser based on the real-time images. This invention is used to automatically adjust control parameters according to the processing trajectory control requirements in complex processing tasks, ensuring processing accuracy.

Description

Technical Field

[0001] This invention relates to the field of femtosecond laser application technology, specifically to a femtosecond laser micro / nano fabrication device based on dynamic focusing. Background Technology

[0002] Femtosecond lasers are a type of laser technology that operates in the form of ultrashort pulses. The pulse width is much smaller than the electron-phonon coupling time (1-100 picoseconds), ensuring that energy acts directly on the electron layer. The pulse duration is extremely short, avoiding heat diffusion. The heat-affected zone is almost negligible, hence the name "cold processing." It can significantly reduce damage to surrounding tissues during processing, making it suitable for fine micro- and nano-scale fabrication. It can achieve sub-micron or even nanometer-level processing accuracy and is suitable for manufacturing high-precision optical components and microelectromechanical systems.

[0003] While femtosecond laser technology offers unique advantages in practical applications, such as high precision, high efficiency, and non-thermal effects, it also has some drawbacks and limitations. Different materials have varying absorption rates of laser light, which can affect processing quality and depth. For example, some highly reflective metals may require special treatment or auxiliary gases for effective processing. Furthermore, mechanical vibrations and temperature changes can still affect processing accuracy during actual processing. Although femtosecond laser processing is known as "cold processing," thermal effects can still occur under multi-pulse or high-energy-density conditions, leading to material deformation or residual stress. This can affect the mechanical properties and dimensional accuracy of the processed parts.

[0004] Therefore, existing technologies typically employ intelligent processing control to ensure precision during processing. For example, Chinese Patent Publication No. CN101480757B discloses a micro-precision processing system for modifying material surfaces using femtosecond lasers. This system utilizes a femtosecond laser as the processing light source, leveraging its unique ultra-short duration and ultra-high peak power characteristics, combined with an optical system and a high-precision three-dimensional stage, and controlled by software programs to perform fine processing of material surface modification. However, this process requires manual pre-setting and adjustment of control parameters, making it difficult to automatically optimize parameters based on actual conditions, leading to inconvenience during use. Therefore, this invention provides a highly intelligent femtosecond laser micro / nano processing device that automatically adjusts control parameters according to the processing trajectory requirements during the actual processing, ensuring processing precision. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a femtosecond laser micro / nano processing device based on dynamic focusing, which automatically adjusts control parameters according to the processing trajectory control requirements in complex processing tasks to ensure processing accuracy.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a femtosecond laser micro-nano processing device based on dynamic focusing, comprising a processing stage for mounting the workpiece to be processed, a driving mechanism for driving the processing stage to move along the processing trajectory at the bottom of the processing stage, and a laser for generating femtosecond laser pulses above the processing stage; a rotating module and a beam contraction mechanism are sequentially arranged along the irradiation direction of the femtosecond laser pulses.

[0007] The rotating module includes a first optical path system for illuminating the workpiece to be processed on the processing table with a processing trajectory and a second optical path system for illuminating the workpiece to be processed with a detection trajectory. The second optical path system is arranged in a ring around the first optical path system. A first beam splitter and a reflector are provided between the first optical path system and the second optical path system. A power component for adjusting the reflection direction of the first beam splitter is fixedly connected to one side of the first beam splitter.

[0008] The first optical path system uses a laser and a beam-shrinking mechanism as the optical path for transmission. The beam-shrinking mechanism is used to adjust the beam diameter and to form polarized light with different polarization states.

[0009] The first beam splitter is located between the laser and the beam shrinking mechanism. The first beam splitter is used to split the femtosecond laser pulse into two beams. The reflector is arranged at a 45-degree angle to the direction of illumination of the femtosecond laser pulse. The reflector is used to reflect one beam into a probe beam parallel to the femtosecond laser pulse. The second optical path system includes a second beam splitter located on the probe beam. A CCD camera for acquiring real-time image data is provided on the probe beam in the refraction direction of the second beam splitter.

[0010] It also includes a control module electrically connected to the beam-shrinking mechanism and the CCD camera, with the lens of the CCD camera facing the position where the workpiece to be processed is mounted on the processing table, and a filter is provided between the CCD camera and the reflector.

[0011] The control module is used to obtain the cutting point position corresponding to the first optical path system and the pre-processing point position corresponding to the second optical path system based on real-time image data. It sends adjustment commands to the power component based on the time sequence of the processing trajectory, obtains the comparison image data corresponding to the pre-processing point position, converts the comparison image data into the corresponding beam position, compares the beam position with the processing trajectory for consistency, and adjusts the power of the beam shrinking mechanism and the laser based on the consistency result.

[0012] Furthermore, the beam-splitting mechanism includes a polarizing beam splitter, which is used to decompose the incident light into two linearly polarized light beams with polarization directions perpendicular to each other, forming two first side-branch optical paths and a second side-branch optical path perpendicular to the surface of the workpiece to be processed.

[0013] The beam formed by the first side branch optical path is circularly polarized light, and the first side branch optical path includes components for converting linearly polarized light into circularly polarized light. Waveplates and several devices for adjusting the polarization direction of linearly polarized light. A waveplate; the beam formed by the second side branch is linearly polarized light, and the second side branch includes several components for adjusting the polarization direction of the linearly polarized light. Waveplate, each A device for driving is fixedly connected to one side of the waveplate. The first driving element rotates the waveplate; and two side optical paths are provided with lens groups for adjusting the beam diameter. The lens groups include a negative lens and a positive lens. A second driving element for driving vertical movement is fixedly connected to one side of the negative lens and the positive lens.

[0014] Furthermore, a beam-shaping lens is provided between the beam-shrinking mechanism and the lens group to optimize beam quality.

[0015] Furthermore, the control module is used to input and store the processing trajectory and the contour trajectory of the workpiece to be processed. The processing trajectory includes the coordinates of the processing point position and the spot area corresponding to the coordinates of the processing point position. The coordinates of the processing point position also include the moving speed and moving direction corresponding to the drive mechanism. The coordinates of the processing point position are determined based on the contour trajectory of the workpiece to be processed.

[0016] The control module is used to divide the contour trajectory into several grid regions of the same size based on the machining trajectory, and to continuously number the grid regions based on the time sequence of the machining point position coordinates in the machining trajectory. Then, corresponding machining orientation and spot regions are added to the continuously numbered grid regions.

[0017] The drive mechanism is used to move according to the machining point position coordinates based on the time sequence, and according to the moving speed and moving direction corresponding to the machining point position coordinates; at the same time, it adds conversion commands to the first drive component based on the machining point position coordinates, and the first drive component drives the first drive component according to the conversion commands. The waveplate rotates to irradiate the surface of the workpiece with circularly or linearly polarized light according to the processing trajectory; and adjustment commands are added to the second drive component based on the light spot area corresponding to the processing point position coordinates.

[0018] Meanwhile, the control module sends adjustment commands to the power component based on the movement direction in the time sequence. The power component controls the first beam splitter to face the movement direction based on the adjustment commands, obtains the comparison image data corresponding to the current time pre-processing point position, and then converts the comparison image data into the corresponding beam position.

[0019] Then, based on the coordinates of the processing point corresponding to the cutting point, the pre-display trajectory corresponding to the pre-processing point is determined. The pre-display trajectory includes the area region in the grid area. The beam position and the area region are overlapped and displayed. If they overlap, a maintenance command is added to the beam shrinking mechanism and the laser. If they do not overlap, an alarm command is sent to the outside. At the same time, the offset between the center of the beam position and the center of the area region is calculated. Based on the offset, the adjustment is performed according to the conversion command corresponding to the original first driving component, and a power reduction command is added to the laser.

[0020] Furthermore, the grid area is set based on the movement distance corresponding to the movement speed within a preset time interval.

[0021] Furthermore, the control module is also used to classify the shape of the processing trajectory into regions. Based on the movement direction corresponding to the current processing point position coordinates, the shape of the processing trajectory corresponding to the movement direction is obtained. If the shape of the processing trajectory is consistent with the movement direction, the corresponding grid region is marked as a straight line region; if the shape of the processing trajectory is inconsistent with the movement direction, the grid region is marked as a parallel region.

[0022] The control module sends parallel processing commands to the rotation module and the beam-shrinking mechanism based on the regions marked as parallel regions.

[0023] Furthermore, the control module is also used to send a beam-reduction command to the second drive unit corresponding to the current time when the pre-processing point is located in the area marked as a straight line, thereby reducing the beam size of circularly polarized light or linearly polarized light.

[0024] Furthermore, the control module is also used to determine the pre-display trajectory corresponding to the pre-processing point position based on the processing point position coordinates corresponding to the cutting point position, and to convert the image data into the corresponding light spot area and polarized light shape. When the beam position overlaps with the area region, the shape of the light spot area and the area region are compared for similarity. If they are similar, a maintenance command is added to the beam contraction mechanism and the laser. If they are not similar, a deflection command is added to the first driving component based on the protrusion of the area region shape. When the beam position does not overlap with the area region, the offset between the center of the light spot area and the center of the area region is calculated, and a corresponding conversion command is added to the first driving component based on the offset orientation of the light spot area and the area region center. The control module also compares the area region with the polarized light shape for similarity. If they are similar, a maintenance command is added to the laser. If they are not similar, a power reduction command is added to the laser.

[0025] Furthermore, the control module is also electrically connected to a dual-wavelength infrared thermometer for real-time measurement of the surface temperature data of the workpiece to be processed;

[0026] The control module compares the temperature data with a preset standard value. If the temperature data is greater than the standard value, an alarm command is sent to the outside. If the temperature data is less than the standard value, a maintenance command is sent to the beam shrinking mechanism and the laser.

[0027] Furthermore, the control module is also used to calculate the phase difference between temperature data before and after a given time when the temperature data is less than the standard value, based on the temperature data corresponding to the continuous grid area in the pre-displayed trajectory. The phase difference is compared with the set change value. If the phase difference is greater than the change value, the line shape corresponding to the pre-displayed trajectory is obtained. If the line shape is a straight line, an alarm command is sent to the outside. If the line shape is a curve, the temperature data corresponding to the beam position is established, and the difference between the temperature data at the center of the curve and the temperature data on both sides of the curve is calculated. The difference is compared with the change value. If the difference is greater than the change value, an alarm command is sent to the outside. If the difference is less than the change value, a maintenance command is sent to the beam contraction mechanism and the laser. If the phase difference is less than the change value, a temperature data mark for the continuous beam position is established based on the temperature data over continuous time, and then the height fluctuation change of the workpiece to be processed is added based on the phase difference.

[0028] The above approach has the following beneficial effects:

[0029] 1. This solution processes the machining trajectory by pre-processing point positions, forming a pre-processing trajectory on the surface of the workpiece. This allows for the adjustment of the processing parameters of the first optical path system based on the pre-processing trajectory, improving the accuracy and real-time performance of subsequent processing while ensuring continuous processing in the current time. It also facilitates the pre-processing of the workpiece surface based on the pre-processing trajectory, enabling the output of femtosecond laser power during subsequent processing, or the adjustment of the focusing characteristics of the beam-shrinking mechanism, to meet the requirements of shape consistency and depth processing of the machining trajectory, thereby ensuring processing accuracy.

[0030] 2. This solution, by dynamically switching between linearly polarized and circularly polarized light modes, allows the system to intelligently match the anisotropic properties of different materials. For example, when processing crystalline materials, linearly polarized light can etch along the lattice direction, reducing edge burrs; while circularly polarized light is suitable for amorphous or isotropic materials, achieving uniform ablation. This multi-mode switching mechanism enables the device to adapt to the processing requirements of complex multi-material composite workpieces, expanding its application scenarios.

[0031] 3. This solution is based on a dual feedback loop formed by a CCD camera and a dual-wavelength infrared thermometer: when the spot position shift is detected, the control module not only corrects the beam deflection angle, but also simultaneously calculates the focal length change caused by thermal expansion. Real-time defocus compensation is achieved by dynamically adjusting the lens spacing through the second driving component. It is suitable for high-precision three-dimensional micromachining of curved workpieces.

[0032] 4. This solution uses a pre-processing trajectory formed by pre-processing points to pre-correct and optimize the processing path. The control module adjusts the processing parameters of the first optical path system in real time based on the pre-processing trajectory, such as laser power and focus position, to ensure trajectory accuracy during actual processing, reduce error accumulation, and guarantee the processing accuracy of complex contours. The control module identifies the shape of the processing trajectory and marks parallel areas. The control module sends parallel processing commands, enabling the second optical path system to process parallel paths simultaneously, reducing reset time and improving efficiency. The pre-processing trajectory pre-plans the processing path, reducing redundant movements and further optimizing the process. It can automatically generate processing paths and strategies, reducing manual intervention. Real-time monitoring of the processing process and automatic parameter adjustment optimize processing, improving efficiency and quality. In complex tasks, the automatic optimization capability significantly saves time and manpower.

[0033] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an embodiment of the femtosecond laser micro / nano fabrication device based on dynamic focusing according to the present invention.

[0035] The reference numerals in the accompanying drawings include: 1. Laser; 2. Rotation module; 3. First beam splitter; 31. Reflector; 32. Second beam splitter; 4. Beam shrinking mechanism; 5. Lens group; 6. Processing table; 7. CCD camera; 8. Control module. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] The following detailed description illustrates the specific implementation methods:

[0040] Example 1:

[0041] As attached Figure 1 As shown: A femtosecond laser micro / nano processing device based on dynamic focusing includes a processing stage 6 for mounting the workpiece to be processed. The bottom of the processing stage 6 is provided with a drive mechanism for driving the processing stage 6 to move according to the processing trajectory. The processing stage 6 and the drive mechanism are existing technologies and will not be described in detail in this embodiment. A laser 1 for generating femtosecond laser pulses is provided above the processing stage 6. In this embodiment, the laser 1 can generate ultrashort pulse widths (typically < 1000 fs) and has high peak power, which can effectively process various materials. A rotating module 2 and a beam-shrinking mechanism 4 are arranged sequentially along the irradiation direction of the femtosecond laser pulse.

[0042] The rotating module 2 includes a first optical path system for illuminating the workpiece on the processing table 6 with a processing trajectory and a second optical path system for illuminating the workpiece with a detection trajectory. The second optical path system is arranged in a ring around the first optical path system. A first beam splitter 3 and a reflector 31 are provided between the first and second optical path systems. A power component for adjusting the reflection direction of the first beam splitter 3 is fixedly connected to one side of the first beam splitter 3. Furthermore, a beam-shrinking mechanism 4 is located between the first and second optical path systems and the workpiece to adjust the light spot on the surface of the workpiece by the first and second optical path systems.

[0043] The beam-splitting mechanism 4 includes a polarizing beam splitter, which decomposes the incident light into two linearly polarized beams with mutually perpendicular polarization directions, forming two first and second side-branch optical paths perpendicular to the surface of the workpiece. The beam formed by the first side-branch optical path is circularly polarized light, and the first side-branch optical path includes components for converting the linearly polarized light into circularly polarized light. Waveplates and several devices for adjusting the polarization direction of linearly polarized light. A waveplate; the beam formed by the second side branch is linearly polarized light, and the second side branch includes several components for adjusting the polarization direction of the linearly polarized light. Waveplate, each A device for driving is fixedly connected to one side of the waveplate. The first driving element for rotating the waveplate; and two side optical paths are provided with lens groups 5 for adjusting the beam diameter. The lens group 5 includes a negative lens and a positive lens. A second driving element for driving vertical movement is fixedly connected to one side of the negative lens and the positive lens.

[0044] In this embodiment, precise control of the laser polarization state is achieved by adjusting the angle of the waveplate and the direction of the polarization beam splitter. Linearly polarized light has a fixed electric field vector direction and its focusing characteristics are directional. When linearly polarized light passes through lens group 5, it forms a light spot with a certain aspect ratio on the plane of the workpiece, with the major axis of the spot aligned with the polarization direction. This polarization state is suitable for processing tasks requiring high energy density in a specific direction, concentrating laser energy in that direction and thus improving processing accuracy and efficiency. Circularly polarized light, on the other hand, has a continuously rotating electric field vector direction, and its focusing characteristics are more symmetrical than linearly polarized light. On the surface of the workpiece, the light spot formed by circularly polarized light is symmetrically distributed in a circular pattern, with a more uniform energy distribution. This polarization state is suitable for situations requiring uniform processing in all directions, effectively avoiding processing inconsistencies caused by polarization direction, improving the stability of processing quality, and adapting to different processing paths and needs.

[0045] Lens group 5 is a common Galilean beam shortener, consisting of a negative lens (concave lens) and a positive lens (convex lens), with the distance between the negative and positive lenses equal to the difference in their focal lengths. Its advantages include a compact structure, no internal focusing point, and avoidance of thermal effects, making it suitable for high-power laser applications. Lens group 5 is used to adjust the beam diameter to improve processing accuracy, enabling the laser to be focused onto a smaller area, achieving micro- and nano-scale processing, and providing an important foundation for controlling the cutting point and pre-processing point positions.

[0046] Meanwhile, the second optical path system adopts a ring layout design, and its symmetrical optical path structure can automatically cancel aberrations caused by mechanical vibration. When positional jitter is detected, the control module 8 drives the first beam splitter 3 to perform angle fine adjustment through the power component, meeting the processing requirements of ultra-precision optical components.

[0047] A beam-shaping lens for optimizing beam quality is also provided between the beam-shrinking mechanism 4 and the lens group 5.

[0048] Among them, the beam shaping lens can shape a traditional Gaussian beam into special beam shapes such as Bessel beams and vortex beams. This shaped beam has better propagation characteristics and focusing performance, adapting to the needs of different processing depths and shapes, further improving processing flexibility and precision. For example, Bessel beams have a long depth of focus and small side lobes; by optimizing the beam shaping effect for linearly polarized light, the beam can maintain a relatively stable spot size within a certain range. Vortex beams have a unique spiral phase distribution and hollow intensity distribution; the use of the beam shaping lens achieves uniform energy distribution, thereby enhancing the beam's focusing characteristics. Through the coordinated operation of the beam shaping lens and the polarization control module 8, the cone angle of the Bessel beam can be dynamically adjusted according to the processing depth. During deep hole processing, a long depth of focus beam is generated to maintain sidewall perpendicularity, while during surface microstructure processing, a short depth of focus Gaussian beam is switched to improve lateral resolution.

[0049] The first optical path system uses a laser 1 and a beam-shrinking mechanism 4 as the optical transmission path. The beam-shrinking mechanism 4 is used to adjust the beam diameter and to form polarized light with different polarization states. A first beam splitter 3 is located between the laser 1 and the beam-shrinking mechanism 4. The first beam splitter 3 is used to split the femtosecond laser pulse into two beams. One beam is the processing beam (the processing beam is on the same straight line as the femtosecond laser pulse), and the other beam illuminates a reflector 31. The reflector 31 is arranged at a 45-degree angle to the illumination direction of the femtosecond laser pulse. The reflector 31 is used to reflect one beam into a probe beam parallel to the processing beam. The second optical path system includes a second beam splitter 32 located on the probe beam. A CCD camera 7 is provided on the probe beam in the refraction direction of the second beam splitter 32 for acquiring real-time image data. The CCD camera 7 is also used to acquire image data of the processing beam in the first optical path system (not shown in the figure).

[0050] It also includes a control module electrically connected to the beam-shrinking mechanism 4 and the CCD camera 7. The lens of the CCD camera 7 faces the position where the workpiece to be processed is mounted on the processing table 6. A filter is provided between the CCD camera 7 and the reflector 31.

[0051] The control module 8 is used to obtain the cutting point position corresponding to the first optical path system and the pre-processing point position corresponding to the second optical path system based on real-time image data, send adjustment commands to the power component based on the time sequence of the processing trajectory, obtain the comparison image data corresponding to the pre-processing point position, convert the comparison image data into the corresponding beam position, compare the beam position with the processing trajectory for consistency, and adjust the power of the beam shrinking mechanism 4 and the laser 1 based on the consistency result.

[0052] The control module 8 is used to input and store the processing trajectory and the contour trajectory of the workpiece to be processed. The processing trajectory includes the coordinates of the processing point position and the spot area corresponding to the processing point position coordinates. The processing point position coordinates also include the moving speed and moving direction corresponding to the driving mechanism. The processing point position coordinates are determined based on the contour trajectory of the workpiece to be processed. In this embodiment, the contour trajectory of the workpiece to be processed is determined by the existing laser scanning method and supplemented by the visual inspection method. This embodiment will not elaborate further.

[0053] Control module 8 is used to divide the contour trajectory into several uniformly sized grid regions based on the machining trajectory, and to continuously number the grid regions based on the temporal order of the machining point position coordinates in the machining trajectory. Then, corresponding machining orientations and spot areas are added to the continuously numbered grid regions. The drive mechanism is used to move according to the machining point position coordinates in the temporal order, according to the moving speed and moving orientation corresponding to the machining point position coordinates. Simultaneously, it adds conversion commands to the first drive component based on the machining point position coordinates, and the first drive component drives the first drive component based on the conversion commands. The waveplate rotates to irradiate the surface of the workpiece with circularly polarized or linearly polarized light according to the processing trajectory; and adjustment commands are added to the second drive component based on the light spot area corresponding to the processing point position coordinates.

[0054] Simultaneously, the control module 8 sends adjustment commands to the power component based on the movement direction in chronological order. The power component controls the first beam splitter 3 to move in the direction of movement based on the adjustment commands, acquires the comparison image data corresponding to the current pre-processing point position, and then converts the comparison image data into the corresponding beam position. Based on the processing point position coordinates corresponding to the cutting point position as the center, the pre-display trajectory corresponding to the pre-processing point position is determined. The pre-display trajectory includes the area region in the grid area. The beam position and the area region are overlapped and displayed. If they overlap, a maintenance command is added to the beam shrinking mechanism 4 and the laser 1. If they do not overlap, an alarm command is sent to the outside world. In this embodiment, the outside world is the display panel on the surface of the device. At the same time, the offset between the center of the beam position and the center of the area region is calculated. Based on the offset, the adjustment is performed according to the conversion command corresponding to the original first driving component, and a power reduction command is added to the laser 1.

[0055] For example, by identifying the machining trajectory and contour trajectory, the location area of ​​the machining trajectory on the surface of the workpiece to be processed can be determined. By dividing the area into grid regions, the location on the surface of the workpiece to be processed can be determined based on the cutting point and pre-processing point. At the same time, during continuous femtosecond machining, the numbered grid regions are used to convert continuous parameter control into interval machining parameter control, reducing the time error accumulated over time, thereby improving the accuracy of machining parameter execution in different regions.

[0056] In the adjustment and control based on the cutting point position and the pre-processing point position, the orientation of the femtosecond laser pulse is adjusted by the reflection of the first beam splitter 3 to meet the needs of femtosecond laser processing in different directions, so that the second optical path system performs pre-processing according to the forward direction of the processing trajectory. By pre-processing the forward direction of the processing trajectory through the pre-processing point position, it is determined whether the beam position in the comparison image data is consistent with the pre-processing trajectory, thereby determining whether inaccuracies are caused by external factors such as device jitter and temperature. The processing trajectory of the beam shrinking mechanism 4 is adjusted by the offset to reduce the generation of small displacements during femtosecond laser processing and ensure processing accuracy.

[0057] In this embodiment, by dynamically switching between linearly polarized and circularly polarized light modes, the system can intelligently match the anisotropic properties of different materials. For example, when processing crystalline materials, linearly polarized light can be used for directional etching along the lattice direction, reducing edge burrs; while circularly polarized light is suitable for amorphous or isotropic materials, achieving uniform ablation. This multi-mode switching mechanism enables the device to adapt to the processing requirements of complex multi-material composite workpieces, expanding its application scenarios.

[0058] Example 2:

[0059] The difference from Embodiment 1 is that the grid area is set based on the moving distance corresponding to the moving speed within a preset time interval.

[0060] The specific implementation process is as follows: the moving speed within the current time interval is compared and processed to adapt the division of the grid area to the movement of the drive mechanism, so that the machining trajectory forming process matches the time control sequence, which facilitates the subsequent backtracking and analysis of the machining process. This allows for a deeper understanding of the impact of various factors on the machining results, providing support for further improving machining control parameters and machining accuracy.

[0061] Example 3:

[0062] The difference from Embodiment 2 is that the control module 8 is also used to perform region classification processing on the shape of the processing trajectory. The region classification processing is based on the distance between the first optical path system and the second optical path system for positioning processing. Based on the movement orientation corresponding to the current processing point position coordinates, the shape of the processing trajectory corresponding to the movement orientation is obtained. If the shape of the processing trajectory is consistent with the movement orientation, the corresponding grid area is marked as a straight line area; if the shape of the processing trajectory is inconsistent with the movement orientation, the grid area is marked as a parallel area. The control module 8 sends parallel processing instructions to the rotation module 2 and the beam contraction mechanism 4 based on the marked parallel areas.

[0063] For example, the second optical path system can simultaneously process shapes where some processing paths are parallel, thereby improving processing efficiency in femtosecond laser processing, reducing reset processing in subsequent processes, and meeting the control requirements of continuous processing. During parallel processing, the control module 8 intelligently allocates energy density based on grid numbers, and the time optimization strategy reduces energy consumption while ensuring processing depth, effectively avoiding heat accumulation and extending the lifespan of the laser 1.

[0064] The control module 8 is also used to send a beam-reduction command to the second drive unit corresponding to the current time when the pre-processing point is located in the area marked as a straight line, thereby reducing the beam size of circularly polarized light or linearly polarized light.

[0065] For example, by reducing the size of circularly or linearly polarized light beams, a narrower trajectory can be formed to process the workpiece, reducing damage to the workpiece surface at pre-processing points. This also allows the second optical path system to cover the trajectory of the workpiece surface during the subsequent processing of the first optical path system, ensuring the processing accuracy of the shape formed by the subsequent processing trajectory. Furthermore, the narrow processing trajectory facilitates the destruction of the workpiece surface, allowing the laser to irradiate the interior during the subsequent processing of the first optical path system, ensuring the required processing depth.

[0066] By rotating the negative / positive lens group 5 of the linkage beam-shrinking mechanism 4 and the λ / 2 waveplate, when the processing trajectory changes from the macroscopic contour to the microscopic features, that is, when the pre-processing point position changes to the cutting point position, the control module 8 automatically switches the processing mode to achieve the best balance between processing efficiency and accuracy.

[0067] Example 4:

[0068] The difference from Embodiment 3 is that the control module 8 is also used to determine the pre-display trajectory corresponding to the pre-processing point position based on the processing point position coordinates corresponding to the cutting point position, and to convert the image data into the corresponding light spot area and polarized light shape; when the beam position overlaps with the area region, the light spot area and the shape of the area region are compared for similarity. If they are similar, a maintenance command is added to the beam contraction mechanism 4 and the laser 1; if they are not similar, a deflection command is added to the first driving member based on the protrusion of the area region shape; when the beam position does not overlap with the area region, the offset between the center of the light spot area and the center of the area region is calculated, and a corresponding conversion command is added to the first driving member based on the offset orientation of the light spot area and the center of the area region; and a similarity comparison is made between the area region and the polarized light shape. If they are similar, a maintenance command is added to the laser 1; if they are not similar, a power reduction command is added to the laser 1.

[0069] For example, by adding a deflection command, subsequent illumination of the area is deflected, making the processing area formed by the first optical path system more consistent with the processing trajectory, thereby further improving processing accuracy. Then, by determining the overlap between the beam position and the area, the consistency between the femtosecond laser pulse and the processing trajectory during subsequent laser processing is controlled to ensure processing accuracy. Finally, by controlling the consistency of the polarization shape, the power of laser 1 is controlled to reduce processing depth and processes that do not conform to the processing trajectory, thereby improving the accuracy of subsequent processing trajectories.

[0070] Example 5:

[0071] The difference from Embodiment 4 is that the control module 8 is also electrically connected to a dual-wavelength infrared thermometer for real-time measurement of the temperature data of the surface of the workpiece to be processed; the control module 8 is used to compare the temperature data with the preset standard value. If the temperature data is greater than the standard value, an alarm command is sent to the outside; if the temperature data is less than the standard value, a maintenance command is added to the beam-shrinking mechanism 4 and the laser 1.

[0072] For example, by using a dual-wavelength infrared thermometer with two different wavelengths of infrared detection, temperature can be measured more accurately and more comprehensive temperature information can be provided. Since femtosecond laser processing is a "cold processing" process, any abnormal temperature data during processing indicates an abnormality in the control parameters. Therefore, timely alarms can prevent equipment damage and safety accidents.

[0073] The control module 8 is also used to calculate the phase difference between the temperature data before and after a certain time based on the temperature data corresponding to the continuous grid area in the pre-displayed trajectory when the temperature data is less than the standard value. The phase difference is compared with the set change value. If the phase difference is greater than the change value, the line shape corresponding to the pre-displayed trajectory is obtained. If the line shape is a straight line, an alarm command is sent to the outside. If the line shape is a curve, the temperature data corresponding to the beam position is established, and the difference between the temperature data at the center of the curve and the temperature data on both sides of the curve is calculated. The difference is compared with the change value. If the difference is greater than the change value, an alarm command is sent to the outside. If the difference is less than the change value, a maintenance command is added to the beam contraction mechanism 4 and the laser 1 and a maintenance command is sent. If the phase difference is less than the change value, the temperature data mark of the continuous beam position is established based on the temperature data of the continuous time, and the height fluctuation change of the workpiece to be processed is added based on the phase difference.

[0074] By marking the temperature data changes in different regions, the temperature data of the pre-processing point location relative to the surface to be processed is described. Based on the temperature data changes, the surface amplitude changes are determined, which facilitates the control parameter adjustment during the subsequent cutting point location processing, provides a reference for the accuracy of subsequent processing trajectory control, and provides a reference for subsequent beam control.

[0075] A dual feedback loop is formed by using a CCD camera 7 and a dual-wavelength infrared thermometer: when the position of the light spot is detected to be off, the control module 8 not only corrects the beam deflection angle, but also calculates the focal length change caused by thermal expansion. Real-time defocus compensation is achieved by dynamically adjusting the lens spacing through the second drive component, which is suitable for high-precision three-dimensional micromachining of curved workpieces.

[0076] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A femtosecond laser micro-nano machining device based on dynamic focusing, comprising a machining table (6) for mounting an object to be machined, the bottom of the machining table (6) being provided with a driving mechanism for driving the machining table (6) to move according to a machining track, and a laser (1) above the machining table (6) for generating femtosecond laser pulses; characterized in that, A rotating module (2) and a beam-reducing mechanism (4) are arranged in sequence along the irradiation direction of the femtosecond laser pulse; The rotating module (2) comprises a first light path system for forming a machining track irradiation on the workpiece on the machining table (6) and a second light path system for forming a detection irradiation on the workpiece, the second light path system is arranged in a ring shape around the first light path system, a first beam splitter (3) and a mirror (31) are arranged between the first light path system and the second light path system, one side of the first beam splitter (3) is fixedly connected with a power member for adjusting the rotating direction of the first beam splitter (3); The first light path system takes the laser (1) and the beam-reducing mechanism (4) as the light path transmission path, the beam-reducing mechanism (4) is used for adjusting the beam diameter and forming polarized light of different polarization states; The first beam splitter (3) is located between the laser (1) and the beam-reducing mechanism (4), the first beam splitter (3) is used for splitting the femtosecond laser pulse into two beams of light, the mirror (31) is arranged at an angle of 45 degrees with the irradiation direction of the femtosecond laser pulse, the mirror (31) is used for reflecting one beam of light into a detection light parallel to the femtosecond laser pulse; the second light path system comprises a second beam splitter (32) located on the detection light, a CCD camera (7) for obtaining real-time image data is arranged on the detection light in the refractive direction of the second beam splitter (32); It also includes a control module electrically connected with the beam-reducing mechanism (4) and the CCD camera (7), the lens of the CCD camera (7) faces the position where the workpiece is installed on the machining table (6), and a filter is arranged between the CCD camera (7) and the mirror (31); The control module (8) is used for obtaining the cutting point position corresponding to the first light path system and the pre-machining point position corresponding to the second light path system based on the real-time image data, sending an adjusting instruction to the power member based on the time sequence before and after the machining track, obtaining the contrast image data corresponding to the pre-machining point position, and converting the contrast image data into the corresponding beam position, comparing the beam position with the machining track for consistency, and adjusting the power of the beam-reducing mechanism (4) and the laser (1) based on the consistency result. 2.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 1, wherein, The beam-reducing mechanism (4) comprises a polarization beam splitter prism, which is used for splitting the incident light into two beams of linearly polarized light with perpendicular polarization directions, forming two first and second side light paths perpendicular to the surface of the workpiece; The first side branch light path includes a plurality of wave plates for adjusting the polarization direction of linearly polarized light The first side branch light path includes a plurality of wave plates for adjusting the polarization direction of linearly polarized light The second side branch light path includes a plurality of wave plates for adjusting the polarization direction of linearly polarized light The second side branch light path includes a plurality of wave plates for adjusting the polarization direction of linearly polarized light The second side branch light path includes a plurality of wave plates for adjusting the polarization direction of linearly polarized light The second side branch light path includes a plurality of wave plates for adjusting the polarization direction of linearly polarized light 3.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 2, wherein, The beam-reducing mechanism (4) and the lens group are further provided with a beam shaping lens for optimizing the beam quality. 4.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 3, wherein, The control module (8) is used for inputting and storing the machining track and the contour track of the workpiece, the machining track comprises machining point position coordinates and a light spot area corresponding to the machining point position coordinates, the machining point position coordinates further comprise a moving speed and a moving direction corresponding to the driving mechanism, and the machining point position coordinates are determined based on the contour track of the workpiece; The control module (8) is used for dividing the contour track into a plurality of grid areas with consistent sizes based on the machining track, continuously numbering the grid areas based on the time sequence before and after the machining point position coordinates in the machining track, and adding corresponding machining directions and light spot areas based on the continuously numbered grid areas. The driving mechanism is used for moving according to the moving speed and the moving direction corresponding to the machining point position coordinates based on the time sequence of the machining point position coordinates; meanwhile, a conversion instruction is added to the first driving member based on the machining point position coordinates, and the first driving member drives the The wave plate is rotated to make the circularly polarized light or the linearly polarized light irradiate the surface of the object to be machined according to the machining track; and an adjusting instruction is added to the second driving member based on the spot region corresponding to the machining point position coordinates; Meanwhile, the control module (8) sends an adjusting instruction to the power component based on the moving direction of the time sequence, and the power component controls the first beam splitter (3) to move to the moving direction based on the adjusting instruction, obtains the contrast image data corresponding to the current time pre-processing point position, and converts the contrast image data into a corresponding light beam position; Meanwhile, the control module (8) sends an adjusting instruction to the power component based on the moving direction of the time sequence, and the power component controls the first beam splitter (3) to move to the moving direction based on the adjusting instruction, obtains the contrast image data corresponding to the current time pre-processing point position, and converts the contrast image data into a corresponding light beam position; 5.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 4, wherein, The grid region is set based on the moving distance corresponding to the moving speed in the preset time interval. 6.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 5, wherein, The control module (8) is further configured to classify the shape of the machining track into regions, obtain the shape of the machining track corresponding to the moving direction based on the moving direction of the machining point position coordinates at the current time, and mark the corresponding grid region as a straight line region if the shape of the machining track is consistent with the moving direction. If the shape of the machining track is inconsistent with the moving direction, the grid region is marked as a parallel region. The control module (8) sends a parallel machining instruction to the rotating module (2) and the beam narrowing mechanism (4) based on the marked parallel region. 7.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 6, wherein, The control module (8) is further configured to send a beam narrowing instruction to the second drive corresponding to the current time when the pre-processing point is located in the grid region marked as a straight line region, so as to reduce the beam size of the circularly polarized light or linearly polarized light. 8.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 7, wherein, The control module is further configured to, when determining the pre-display track corresponding to the pre-processing point position based on the machining point position coordinates corresponding to the cutting point position as the center, convert the contrast image data into a corresponding light point area and polarized light shape; when the light beam position overlaps with the area region, compare the light point area with the shape of the area region for similarity, and if similar, send a maintenance instruction to the beam narrowing mechanism (4) and the laser (1); if not similar, send a deviation instruction to the first drive based on the protruding part of the shape of the area region; when the light beam position does not overlap with the area region, calculate the offset between the center of the light point area and the center of the area region, and based on the offset direction of the light point area and the center of the area region, add a corresponding conversion instruction to the first drive based on the offset direction; and compare the area region and the polarized light shape for similarity, and if similar, send a maintenance instruction to the laser (1); if not similar, send a power reduction instruction to the laser (1). 9.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 8, wherein, The control module (8) is further electrically connected with a dual-wavelength infrared temperature measuring instrument for measuring the temperature data of the surface of the object to be machined in real time. The control module (8) is configured to compare the temperature data with a preset standard value, and if the temperature data is greater than the standard value, send an alarm instruction to the outside world; if the temperature data is less than the standard value, send a maintenance instruction to the beam narrowing mechanism (4) and the laser (1). 10.The dynamic focusing based femtosecond laser micro-nano processing device according to claim 9, wherein, The control module (8) is further configured to, when the temperature data is less than the standard value, calculate a phase difference value corresponding to the temperature data of the front and rear time based on the temperature data corresponding to the continuous grid area in the pre-display track, compare the phase difference value with a set change value, if the phase difference value is greater than the change value, obtain a line form corresponding to the pre-display track, if the line form is a straight line, send an alarm instruction to the outside world, if the line form is a curve, establish temperature data corresponding to the light beam position, calculate a difference value between the temperature data at the center of the curve and the temperature data on both sides of the curve, compare the difference value with the change value, if the difference value is greater than the change value, send an alarm instruction to the outside world, if the difference value is less than the change value, send a maintenance instruction to the beam shrinking mechanism (4) and the laser (1), if the phase difference value is less than the change value, establish temperature data marks of continuous light beam positions based on the temperature data of continuous time, and then add the height fluctuation change of the continuous workpiece based on the phase difference value.

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