A trajectory-adjustable scanning system and scanning method

Abstract

This invention belongs to the field of laser processing technology and discloses a scanning system and method with adjustable trajectory. In the system, a multi-point generation unit and a rotating scanning unit are used to generate N beams for simultaneous circular trajectory scanning. A trajectory changing unit is used to simultaneously increase the exit angle of the N beams in the circular scan, with each beam increasing its exit angle by the same amount at any given time, but the increase in exit angle at different times is adjustable. Subsequently, after focusing, different beams correspond to different focusing surfaces, forming N focused spots that simultaneously scan N target trajectories on the object being processed. The N target trajectories are either elliptical or circular. This system allows for flexible adjustment of the scanning trajectory, adapting to different needs in refractive surgery.

Description

Technical Field

[0001] This invention belongs to the field of laser processing technology, and more specifically, relates to a scanning system and scanning method with adjustable trajectory. Background Technology

[0002] Femtosecond laser-assisted in retinal refractive surgery (hereinafter referred to as "femtosecond surgery") is an effective and minimally invasive method for treating myopia. Its treatment principle is to use a femtosecond laser to carve a small lens in the corneal stroma and then remove it, thereby increasing the radius of curvature of the corneal surface, reducing the corneal refractive power, and achieving the purpose of correcting myopia.

[0003] Improving laser scanning speed and shortening surgical time is a key development direction for femtosecond LASIK surgical equipment. During laser scanning, a negative pressure ring is used to fix the eyeball. The longer the negative pressure is maintained, the more uncomfortable the patient becomes, and the higher the probability of desorption occurs. Desorption means surgical failure, requiring termination of the procedure or a second surgery. Furthermore, prolonged negative pressure can also cause postoperative complications such as subconjunctival hemorrhage. Therefore, shortening the laser scanning time can reduce the negative pressure time and improve surgical safety.

[0004] Chinese patent CN111281651B proposes a method for generating a symmetric scanning surface required for surgery using a dynamic multi-point generator in conjunction with a rapid rotating scanner. This method can achieve concentric circle scanning in multifocal three-dimensional space. However, this method has limitations: it can only generate circular scanning trajectories and can only correct myopia in refractive surgery, but cannot correct astigmatism, because astigmatism requires an ellipsoidal cutting surface. In addition, since the diffraction angle of dynamic diffraction devices is generally small, it cannot meet the requirements of a large scanning field of view in refractive surgery. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a scanning system and scanning method with adjustable trajectory, the purpose of which is to realize the flexible adjustment of the scanning trajectory to adapt to different needs of refractive surgery.

[0006] To achieve the above objectives, the present invention provides a trajectory-adjustable scanning system, comprising a control unit and a multi-point generation unit, a rotation scanning unit, and a trajectory changing unit arranged sequentially along the optical path, wherein:

[0007] The multi-point generation unit is used to split the incident laser beam into N beams, and the number of beams can be adjusted.

[0008] The rotating scanning unit is used to enable the N beams to perform synchronous circular trajectory scanning;

[0009] The trajectory change unit is used to synchronously increase the exit angle of the N beams of the circular scan, and the exit angle of each beam is increased by the same amount at the same time, while the exit angle of each beam is adjustable at different times.

[0010] The N beams emitted from the trajectory change unit are focused to form N focused light spots that simultaneously scan the N target trajectories of the workpiece. The N target trajectories are either elliptical or circular.

[0011] The control unit is used to control the multi-point generation unit, the rotation scanning unit and the trajectory changing unit according to the required target trajectory, so that N focused light spots can scan synchronously on the processed object along the corresponding target trajectory.

[0012] Optionally, the trajectory changing unit is a galvanometer or a rotating mirror.

[0013] Optionally, the trajectory changing unit includes a lens for adjusting the scanning angle in the X-axis direction and a lens for adjusting the scanning angle in the Y-axis direction. The angle adjustment components of the trajectory changing unit along the X-axis direction and along the Y-axis direction are respectively... , , , satisfy:

[0014]

[0015] In the formula, , These are the angle adjustment components along the X-axis and Y-axis when correcting a circular trajectory to an elliptical trajectory. , satisfy:

[0016]

[0017] In the formula, =Semi-major axis of the corrected elliptical trajectory - radius of the original circular trajectory =Semi-minor axis of the corrected elliptical trajectory - radius of the original circular trajectory The rotation angle of the beam after passing through the rotating scanning unit. The angle between the major axis of the ellipse trajectory and the X-axis;

[0018] , These represent the angle adjustment components along the X-axis and Y-axis when the diameter of the circular trajectory needs to be increased. , satisfy:

[0019]

[0020] In the formula, It is the difference in the radius of the circular trajectory before and after the diameter field of view is expanded;

[0021] , These represent the angle adjustment components along the X-axis and Y-axis when error compensation is required for the circular trajectory. , satisfy:

[0022]

[0023] In the formula, To compensate for the angle error value, The initial phase angle for error compensation.

[0024] Optionally, when N is greater than 1, the rotating scanning unit is used to enable the N beams to perform concentric circular trajectory scanning synchronously, and the N target trajectories are concentric elliptical trajectories or concentric circular trajectories.

[0025] Optionally, the N target trajectories are located on different focal planes.

[0026] Optionally, the multi-point generation unit is a digital micromirror device or a liquid crystal spatial light modulator, and the multi-point generation unit achieves intensity or phase modulation of the light beam by loading or switching holograms.

[0027] Optionally, the rotating scanning unit is a Dowell prism, an Abbe-Coni prism, or a K-shaped arrangement of three reflecting mirrors driven by a power element.

[0028] Optionally, the scanning system further includes a focusing unit for focusing the N beams emitted from the trajectory changing unit.

[0029] Optionally, the system is used for corneal refractive surgery.

[0030] The present invention also provides a trajectory-adjustable scanning method, which is implemented based on the trajectory-adjustable scanning system as described in any of the preceding claims, the method being executed by a control unit, the method comprising:

[0031] Calculate the scanning parameters required for the 3D machined object, including the number of focal points N for synchronous scanning and the required target trajectory;

[0032] All target trajectory contour lines are divided into multiple layers and the scanning parameters of each layer are determined. Each layer has N target trajectories that are scanned synchronously. The target trajectories are either elliptical or circular. Based on the scanning parameters required for each layer, the control data required for the corresponding multi-point generation unit, rotation scanning unit, and trajectory change unit are generated.

[0033] The control data required for scanning the current layer is loaded into the multi-point generation unit, the rotation scanning unit, and the trajectory change unit respectively, so as to realize the scanning trajectory of the current layer. After the scanning of the current layer is completed, the scanning of the next layer is carried out until the scanning trajectory of all layers is completed.

[0034] In summary, compared with the prior art, the technical solutions conceived in this invention have the following main advantages:

[0035] In this invention, by combining a multi-point generation unit and a rotating scanning unit, single-point or multi-point scanning can be achieved. Furthermore, by incorporating a trajectory adjustment unit, the exit angle of each incident laser beam is simultaneously increased. The increase in exit angle for each laser beam is the same at any given time, but the increase at different times is adjustable. By setting and adjusting the exit angle using the trajectory adjustment unit, a circular trajectory can be changed to an elliptical trajectory, or the trajectory diameter can be increased to achieve a larger field of view. It can also compensate for trajectory errors caused by the multi-point generation unit and the rotating scanning unit. Overall, the trajectory-adjustable scanning system provided by this invention allows for flexible adjustment of the scanning trajectory, making it particularly suitable for three-dimensional scanning. It significantly improves scanning speed, enabling rapid refractive surgery and meeting the needs of rapid laser scanning, refractive and astigmatism correction, and a large scanning field of view in laser refractive surgery. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a trajectory-adjustable scanning system according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of correcting a circular trajectory to an elliptical trajectory in one embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of increasing the diameter of a circular trajectory in one embodiment of the present invention;

[0039] Figure 4 This is a top view schematic diagram of multi-point scanning after focusing in one embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of surface scanning in one embodiment of the present invention;

[0041] Figure 6 This is a top view of the scanning trajectory of the system for correcting astigmatism in one embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0043] This invention provides a trajectory-adjustable scanning system, comprising at least a control unit and a multi-point generation unit, a rotation scanning unit, and a trajectory changing unit arranged sequentially along the optical path. Figure 1 The diagram shown illustrates the structure of a trajectory-adjustable scanning system according to an embodiment of the present invention. It includes at least a multi-point generation unit 3, a rotation scanning unit 4, a trajectory changing unit 5, and a control unit 9. Furthermore, the system may also include a light source unit 1 and a focusing unit 6.

[0044] Laser source unit 1 can provide a light beam that interacts with the workpiece, including effects such as photo-induced fracturing, photo-etching, photo-crosslinking, photothermal effects, and photochemical reactions. The laser source can be a continuous-wave laser or a pulsed laser, and the exposure time or repetition frequency and laser energy can be controlled. Pulsed lasers have one or more fixed selectable fundamental frequencies. Rapid adjustment of the pulsed laser's repetition frequency is achieved through frequency division using a high-speed optical shutter. The high-speed optical shutter can be an acousto-optic modulator (AOM) or an electro-optic modulator (EOM), etc. For example, laser source unit 1 can be a femtosecond laser, providing beam 2 for subsequent processing. Specifically, the laser wavelength is from 800 nm to 1500 nm, the repetition frequency is from 10 kHz to 10 MHz, and the laser power is from 0.1 W to 1000 W.

[0045] The multi-point generation unit 3 can split the beam provided by the laser source unit 1 into N beams. N≥1, meaning that the multi-point generation unit 3 can split only one beam or multiple beams, which can be adjusted according to needs. Specifically, the multi-point generation unit 3 can be a diffraction device or a beam splitter, preferably a dynamic diffraction device, such as a digital micromirror device (DMD) or a liquid crystal spatial light modulator (SLM), which modulates the intensity or phase of the beam by loading or switching holograms.

[0046] The rotating scanning unit 4 can perform a circular scan of N beams of light. It should be noted that during the circular scan, if N > 1, all N beams of light will perform concentric circular scans with the same axis as the center of rotation. The rotating scanning unit 4 can be a power element such as a Dowell prism driven by a motor, an Abbe-Coni prism, or a K-shaped arrangement of three reflecting mirrors.

[0047] The trajectory adjustment unit 5 is used to synchronously increase the exit angle of the N beams in the circular scan, and the exit angle of each laser beam increases by the same amount at the same time. The increase in exit angle at different times is adjustable. That is, the trajectory adjustment unit 5 can increase the scanning angle of the N beams in the circular scan in real time, synchronously, and simultaneously, and the increase in angle for the N beams is the same. By further adjusting the exit angle through the trajectory adjustment unit 5, the circular trajectory after the focusing unit 6 can be adjusted into an elliptical trajectory, or the trajectory diameter can be increased to achieve a larger field of view. It can also compensate for the trajectory errors caused by the multi-point generation unit and the rotating scanning unit. In other words, the trajectory adjustment unit 5 may achieve three functions: the first function is to realize the transformation of the laser scanning trajectory, modifying the circular scanning trajectory to other trajectories, such as modifying the above-mentioned circular scanning trajectory to an elliptical scanning trajectory that can simultaneously correct refractive and astigmatic errors; the second function is to expand the beam scanning angle to compensate for the small diffraction angle of the dynamic diffraction device used by the multi-point generation unit, which cannot meet the requirements of the large scanning field of view in refractive surgery; the third function is to compensate for the scanning angle error introduced by the rotating scanning unit. Specifically, the trajectory changing unit 5 can be a galvanometer, a rotating mirror, or other device that can change the beam exit angle.

[0048] The focusing unit 6 can focus the light beam to obtain a greater energy density and form a spatially arranged focused light spot 7. The focusing unit can be an objective lens, field lens, etc.

[0049] The control unit 9 can calculate the scanning trajectory and synchronously control the multi-point generation unit 3, the rotation scanning unit 4, and the trajectory changing unit 5 to collaboratively generate one or more focused light spots, which scan the corresponding target trajectory on the processed object. Furthermore, if N > 1, the N target trajectories are concentric elliptical or concentric circular trajectories, and the N target trajectories can be located on different focal planes, thereby realizing multifocal refractive surgery curved surface trajectory scanning, especially astigmatism correction surgery curved surface trajectory scanning.

[0050] The following describes the operation of adjusting the scanning trajectory of trajectory change unit 5.

[0051] Assuming the rotational speed of the rotating scanning unit 4 is φ, and the incident angle of the laser onto the rotating scanning unit 4 is φ. After passing through the rotating scanning unit 4, the scanning speed of the beam is generally 2μm, and the angle between the beam and the optical axis is always 0°. When the trajectory changing unit does not perform any modulation, the scanning trajectory after passing through the focusing unit 6 is as follows:

[0052]

[0053] In the formula, These are the coordinates of the laser's scanning trajectory on the focusing plane. Focal length This refers to the rotation angle of the beam after passing through the rotating scanning unit 4. At this point, the scanning trajectory is a circular trajectory. The trajectory changing unit 5 can add an angle to the beam emitted from the rotating scanning unit 4. The scan trajectory after focusing is as follows:

[0054]

[0055] because If the angle is small, the scanning trajectory can be approximated as:

[0056]

[0057] As can be seen from formula (3), as long as adjustments are made in real time... This allows for real-time adjustment of the scanning trajectory.

[0058] In one embodiment, when the trajectory changing unit 5 uses a galvanometer or a rotating mirror, both the galvanometer and the rotating mirror include a lens for adjusting the scanning angle in the X-axis direction and a lens for adjusting the scanning angle in the Y-axis direction, with the included angle... It can be followed The continuous real-time changes, including the included angle If we treat it as a vector and perform orthogonal decomposition, then

[0059]

[0060] In the formula, For the trajectory change unit, adjust the angle component along the X-axis. For the trajectory change unit, the angle adjustment component along the Y-axis direction should be noted that all coordinates in the system have the same X-axis and Y-axis directions.

[0061] like Figure 2 The diagram shown illustrates how a circular trajectory is corrected to an elliptical trajectory in one embodiment of the present invention. When it is necessary to correct the circular trajectory to an elliptical trajectory, the angle adjustment component of the trajectory changing unit 5 along the X-axis is... The angle adjustment component along the Y-axis is Both conditions are met:

[0062]

[0063] in, = Semi-major axis of ellipse trajectory - radius of circular trajectory = Semi-minor axis of ellipse - radius of circle, The angle between the major axis of the elliptical trajectory and the X-axis, i.e., the astigmatic axis angle in refractive surgery, is provided to the trajectory change control unit 5. This allows you to control the included angle. With rotation angle It undergoes an elliptical transformation, and then the circular trajectory is corrected to an elliptical trajectory.

[0064] like Figure 3 The diagram shown illustrates an embodiment of the present invention for increasing the diameter of a circular trajectory. When it is necessary to increase the diameter of the circular trajectory, the angular adjustment component of the trajectory changing unit 5 along the X-axis direction is... The angle adjustment component along the Y-axis is Both conditions are met:

[0065]

[0066] In the formula, It is the difference in radius of the circular trajectory before and after the field of view is expanded. A signal is provided to the trajectory change control unit 5. This allows you to control the included angle. The direction changes with the rotation angle It changes in a circular pattern, and then the diameter of the circular trajectory increases.

[0067] Due to manufacturing and installation errors, the rotating scanning unit 4 may introduce trajectory errors. These trajectory errors result in a circular trajectory with a scanning speed of φ, causing the scanning trajectory to change from formula (1) to:

[0068]

[0069] in, It's an angular error. The initial phase angle for error compensation.

[0070] When error compensation is required for the circular trajectory, the angle adjustment component of the trajectory change unit 5 along the X-axis is: The angle adjustment component along the Y-axis is Both conditions are met:

[0071]

[0072] In the formula, The value is for compensating for angular error.

[0073] Provide signals to control trajectory change unit 5 This allows you to control the included angle. Compensate for the trajectory.

[0074] Combining formulas (5), (6), and (8), the control signal of the trajectory change unit can be expressed as:

[0075]

[0076] By applying the above , The control signal can be used to adjust the trajectory through simple calculations.

[0077] Accordingly, the present invention also relates to a scanning method based on the trajectory-adjustable scanning system described above. This method is executed by a control unit and specifically includes:

[0078] Calculate the scanning parameters required for 3D machining of the object. The machining parameters include the number of focal points N for synchronous scanning and the required target trajectory.

[0079] All target trajectory contour lines are divided into multiple layers and the scanning parameters of each layer are determined. Each layer has N target trajectories that are scanned synchronously. The target trajectories are either elliptical or circular. Based on the scanning parameters required for each layer, the control data required for the corresponding multi-point generation unit, rotation scanning unit, and trajectory change unit are generated.

[0080] The control data required for scanning the current layer is loaded into the multi-point generation unit, the rotation scanning unit, and the trajectory change unit respectively, so as to realize the scanning trajectory of the current layer. After the scanning of the current layer is completed, the scanning of the next layer is carried out until the scanning trajectory of all layers is completed.

[0081] Taking refractive surgery as an example, the following describes the procedures for performing multifocal refractive surgery using this system:

[0082] 1. Input the parameters obtained from the patient's preoperative examination into the control unit to calculate the required surgical data, including laser energy, laser pulse frequency, refractive surgery scanning trajectory, and number of scanning focal points N. Specifically, input the parameters such as the required refractive power to be corrected obtained from preoperative information acquisition into the control unit 9. The control unit 9 can calculate the laser energy and number of scanning focal points N required for the surgery, and calculate the tissue thickness to be eliminated at each location using the Munnerlyn equation and the required refractive power. Then, the control unit 9 calculates the surgical surface based on the system's own parameters and generates the corresponding refractive surgery scanning trajectory. If astigmatism is present, a scanning trajectory for astigmatism correction also needs to be generated based on the astigmatism of the target sample. The scanning trajectory data can be a refractive correction, astigmatism correction, or an ellipsoidal scanning trajectory that corrects both refractive and astigmatism simultaneously.

[0083] 2. Based on the refractive surgery scanning trajectory data, the trajectory is divided into multiple layers according to contour lines. Each layer consists of N circular or elliptical trajectories. Based on the scanning data of each layer, the control data required for the corresponding laser source unit, multi-point generation unit, rotation scanning unit, and trajectory modification unit is generated. The control data enables each unit to cooperate in achieving the target scanning trajectory.

[0084] 3. Load or select the control data for the laser source unit, multi-point generation unit, rotation scanning unit, and trajectory changing unit required for a certain layer's trajectory to achieve scanning of the current layer's scanning trajectory. Specifically, the control data for the multi-point generation unit can be one or more holograms. Furthermore, the holograms can be calculated using computational holography algorithms such as GS and WSG. For example, the control unit 9 uses algorithms such as WGS and GS to calculate and generate one or more holograms based on information such as position and depth in the scanning trajectory. The holograms are then loaded into the multi-point generation unit 3 to generate N beams adapted to the scanning trajectory. Specifically, the control data for the rotation scanning unit can be signals of the type of pulse, current, or voltage. Furthermore, the signals contain information controlling the position, rotation direction, and rotation speed of the rotation scanning unit. The control data for the trajectory changing unit can be voltage or current signals. Furthermore, the signals can control the trajectory changing unit to move or remain stationary.

[0085] 4. Repeat step 3 to scan the next layer until the required scan trajectory for the refractive surgery of S1 is completed.

[0086] like Figure 4 The diagram shown is a top view of a multi-point scanning after focusing in one embodiment of the present invention. The scanning trajectory 70a of the previous period is a parallel circular scan by N laser beams, with the center of the circular scan being the same point. The N beams of light perform concentric circle scanning around the rotation center. After scanning one circle, the next period of scanning begins. The angle of the circular scan is changed by the trajectory changing unit 5 to perform the next circle of trajectory scanning, resulting in the scanning trajectory 71a after the scanning angle is changed. The scanning radii of the two scans are different.

[0087] like Figure 5 The diagram shown is a schematic of curved surface scanning in one embodiment of the present invention. During the circular scanning process, the beam is focused by the focusing unit 6 to obtain N focused light spots 7. The scanning trajectory of one circle of the focal spot is N circles or ellipses. Figure 3 As shown, the lasers at different positions on the curved surface scanning trajectory 70b before the scanning angle change are not at the same position on the axial direction of the target sample after focusing. Instead, they are located on a curved surface. The circular scanning is performed by rotating scanning unit 4, and the scanning angle is changed by trajectory changing unit 5. The next scan is performed to obtain the curved surface scanning trajectory 71b after the scanning angle change. After scanning multiple times, the curved surface scanning trajectory is finally realized on the target sample 8.

[0088] like Figure 6 This is a top view of the scanning trajectory for astigmatism correction in one embodiment of the present invention. Figure 4As shown, when the rotating scanning unit 4 is used to perform a circular scan, the top view of the scan trajectory is a perfect circle, which cannot achieve the purpose of correcting astigmatism. Therefore, while performing a circular scan, it is necessary to synchronously control the trajectory changing unit 5 to change the scanning angle of different positions in one scan in real time, so as to change the circular scan trajectory to an elliptical scan trajectory.

[0089] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again" are intended to illustrate the present invention and are not intended to limit the present invention.

[0090] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A scanning system with adjustable trajectory, characterized in that, It includes a control unit and a multi-point generation unit, a rotation scanning unit, and a trajectory changing unit arranged sequentially along the optical path, wherein: The multi-point generation unit is used to split the incident laser beam into N beams, and the number of beams can be adjusted. The rotating scanning unit is used to enable the N beams to perform synchronous circular trajectory scanning; The trajectory change unit is used to synchronously increase the exit angle of the N beams of the circular scan, and the exit angle of each beam is increased by the same amount at the same time, while the exit angle of each beam is adjustable at different times. The N beams emitted from the trajectory change unit are focused to form N focused light spots that simultaneously scan the N target trajectories of the workpiece. The N target trajectories are either elliptical or circular. The control unit is used to control the multi-point generation unit, the rotation scanning unit and the trajectory changing unit according to the required target trajectory, so that N focused light spots can scan synchronously on the processed object along the corresponding target trajectory.

2. The trajectory-adjustable scanning system as described in claim 1, characterized in that, The trajectory change unit is a galvanometer or a rotating mirror.

3. The trajectory-adjustable scanning system as described in claim 2, characterized in that, The trajectory changing unit includes a lens for adjusting the scanning angle in the X-axis direction and a lens for adjusting the scanning angle in the Y-axis direction. The angle adjustment components of the trajectory changing unit along the X-axis direction and along the Y-axis direction are respectively... , , , satisfy: In the formula, , These are the angle adjustment components along the X-axis and Y-axis when correcting a circular trajectory to an elliptical trajectory. , satisfy: In the formula, =Semi-major axis of the corrected elliptical trajectory - radius of the original circular trajectory =Semi-minor axis of the corrected elliptical trajectory - radius of the original circular trajectory The rotation angle of the beam after passing through the rotating scanning unit. The angle between the major axis of the ellipse trajectory and the X-axis; , These represent the angle adjustment components along the X-axis and Y-axis when the diameter of the circular trajectory needs to be increased. , satisfy: In the formula, It is the difference in the radius of the circular trajectory before and after the diameter field of view is expanded; , These represent the angle adjustment components along the X-axis and Y-axis when error compensation is required for the circular trajectory. , satisfy: In the formula, To compensate for the angle error value, This is the initial phase angle for error compensation.

4. The trajectory-adjustable scanning system as described in claim 1, characterized in that, When N is greater than 1, the rotating scanning unit is used to make the N beams perform concentric circular trajectory scanning synchronously, and the N target trajectories are concentric elliptical trajectories or concentric circular trajectories.

5. The trajectory-adjustable scanning system as described in claim 4, characterized in that, The N target trajectories are located on different focal planes.

6. The trajectory-adjustable scanning system as described in claim 1, characterized in that, The multi-point generation unit is a digital micromirror device or a liquid crystal spatial light modulator. The multi-point generation unit achieves intensity or phase modulation of the light beam by loading or switching holograms.

7. The trajectory-adjustable scanning system as described in claim 1, characterized in that, The rotating scanning unit is a Dowell prism, an Abbe-Coni prism, or a K-shaped arrangement of three reflecting mirrors driven by a power element.

8. The trajectory-adjustable scanning system as described in claim 1, characterized in that, The scanning system also includes a focusing unit, which is used to focus the N beams emitted by the trajectory change unit.

9. The trajectory-adjustable scanning system as described in claim 1, characterized in that, The system is used for corneal refractive surgery.

10. A scanning method with adjustable trajectory, characterized in that, Based on the trajectory-adjustable scanning system as described in any one of claims 1 to 8, the method is executed by a control unit, and the method includes: Calculate the scanning parameters required for the 3D machined object, including the number of focal points N for synchronous scanning and the required target trajectory; All target trajectory contour lines are divided into multiple layers and the scanning parameters of each layer are determined. Each layer has N target trajectories that are scanned synchronously. The target trajectories are either elliptical or circular. Based on the scanning parameters required for each layer, the control data required for the corresponding multi-point generation unit, rotation scanning unit, and trajectory change unit are generated. The control data required for scanning the current layer is loaded into the multi-point generation unit, the rotation scanning unit, and the trajectory change unit respectively, so as to realize the scanning trajectory of the current layer. After the scanning of the current layer is completed, the scanning of the next layer is carried out until the scanning trajectory of all layers is completed.

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