Track-adjustable scanning system and scanning method

Abstract

The invention belongs to the related technical field of laser processing, and discloses a track-adjustable scanning system and a track-adjustable scanning method.In the system, a multi-point generation unit and a rotary scanning unit are used for producing N light beams and synchronously performing circular track scanning; the track changing unit is used for synchronously increasing the emergent angles of the N annularly scanned light beams, the emergent angles increased by each laser beam at the same moment are the same, and the emergent angles increased at different moments are adjustable; and then through focusing, different light beams correspond to different focusing surfaces to form N focusing light spots which act on the processed object and synchronously scan N target trajectories, and the N target trajectories are oval trajectories or circular trajectories. By means of the system, the scanning track can be flexibly adjusted, and different requirements of refractive surgery can be met.

Description

Technical Field

[0001] The present invention belongs to the technical field related to laser processing, and more specifically, relates to a scanning system and a scanning method with adjustable trajectory. Background Art

[0002] All-femtosecond laser corneal refractive surgery (hereinafter referred to as "all-femtosecond surgery") is an effective and less damaging means of treating myopia. Its treatment principle is to use a femtosecond laser to carve a small lens in the corneal stroma and remove it, thereby increasing the radius of curvature of the corneal surface, thereby reducing the corneal refractive power and achieving the purpose of correcting myopia.

[0003] Improving the laser scanning speed and shortening the operation time are important development directions of all-femtosecond surgical equipment. During the laser scanning process, a negative pressure ring is needed to fix the eyeball. The longer the negative pressure time, the more uncomfortable the patient will be, and the higher the probability of desorption. The occurrence of desorption means that the operation has failed, and the operation needs to be terminated or a second operation needs to be performed. In addition, long-term negative pressure adsorption can also cause postoperative complications, such as subconjunctival hemorrhage. Therefore, shortening the laser scanning time can reduce the negative pressure time and improve the safety of the operation.

[0004] Chinese patent CN111281651B proposes a method in which a dynamic multi-point generator cooperates with a fast rotating scanner to generate a cycloidal symmetrical scanning surface required for surgery, which can achieve concentric circle scanning in a multi-focal three-dimensional space. However, the limitation of this method is that it can only generate a circular scanning trajectory 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 a dynamic diffraction device 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 defects or improvement needs of the prior art, the present invention provides a scanning system and a scanning method with adjustable trajectory, the purpose of which is to achieve flexible adjustment of the scanning trajectory to adapt to the different needs of refractive surgery.

[0006] To achieve the above object, the present invention provides a scanning system with adjustable trajectory, which includes a control unit and a multi-point generating unit, a rotating scanning unit and a trajectory changing unit arranged in sequence along an optical path, wherein:

[0007] The multi-point generating unit is used to split the incident laser into N beams, and the number of split beams is adjustable;

[0008] The rotating scanning unit is used to make the N light beams synchronously scan circular trajectories;

[0009] The trajectory changing unit is used to synchronously increase the emission angles of the N light beams of the circular scanning, and the emission angles of each light beam increased at the same time are the same, and the emission angles increased at different times are adjustable;

[0010] After the N light beams emitted by the trajectory changing unit are focused, they form N focused light spots that act on the processed object and simultaneously scan N target trajectories, wherein the N target trajectories are elliptical trajectories or circular trajectories;

[0011] The control unit is used to control the multi-point generating unit, the rotating scanning unit and the trajectory changing unit according to the required target trajectory, so that N focused light spots are synchronously scanned along the corresponding target trajectory on the processing object.

[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, and the angle adjustment components of the trajectory changing unit along the X-axis direction and along the Y-axis direction are respectively X and Y. G , Y G , X G , Y G satisfy:

[0014]

[0015] In the formula, X E , Y E They are the angle adjustment component along the X-axis direction and the angle adjustment component along the Y-axis direction when the circular trajectory needs to be corrected to an elliptical trajectory. E , Y E satisfy:

[0016]

[0017] Where A = the semi-major axis of the corrected elliptical trajectory minus the radius of the circular trajectory before correction, B = the semi-minor axis of the corrected elliptical trajectory minus the radius of the circular trajectory before correction, θ is the rotation angle of the beam after the rotating scanning unit, θ E is the angle between the major axis of the elliptical trajectory and the X-axis;

[0018] X A , Y A They are the angle adjustment component along the X-axis direction and the angle adjustment component along the Y-axis direction when the diameter of the circular track needs to be increased. A , Y A satisfy:

[0019]

[0020] Where C is the difference in radius of the circular trajectory before and after the diameter field is enlarged;

[0021] X A , Y A They are the angle adjustment component along the X-axis direction and the angle adjustment component along the Y-axis direction when error compensation of the circular trajectory is required. A , Y A satisfy:

[0022]

[0023] Where E is the angle error value compensated, is the initial phase angle for error compensation.

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

[0025] Optionally, the N target tracks are located on different focusing planes.

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

[0027] Optionally, the rotating scanning unit is a Dove prism or an Abbe-Koenig prism or three reflectors arranged in a K shape driven by a power element.

[0028] Optionally, the scanning system further comprises a focusing unit, and the focusing unit is used to focus the N light beams emitted by the trajectory changing unit.

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

[0030] The present invention further provides a scanning method with adjustable trajectory, which is implemented based on the scanning system with adjustable trajectory as described in any one of the above items, and the method is executed by a control unit, and the method comprises:

[0031] Calculating scanning parameters required for three-dimensional processing of the object, wherein the processing parameters include the number of focal points N of synchronous scanning and the required target trajectory;

[0032] Divide all target trajectory contours into multiple layers and determine the scanning parameters of each layer, each layer having N target trajectories for synchronous scanning, wherein the target trajectories are elliptical trajectories or circular trajectories; generate control data required by the corresponding multi-point generation unit, the rotation scanning unit and the trajectory change unit according to the scanning parameters required for scanning each layer;

[0033] The control data required for scanning the current layer is loaded to the multi-point generation unit, the rotation scanning unit and the trajectory change unit respectively to realize the scanning of the current layer scanning trajectory; when the current layer scanning is completed, the next layer is scanned until the scanning trajectory of all layers is completed.

[0034] In general, compared with the prior art, the above technical solutions conceived by the present invention mainly have the following beneficial effects:

[0035] In the present invention, by combining a multi-point generation unit and a rotating scanning unit, single-point or multi-point scanning can be realized. On this basis, the trajectory change unit is further combined, and the emission angle of each incident laser beam is synchronously increased by the trajectory change unit. The emission angle increased by each laser beam at the same time is the same, and the emission angle increased at different times is adjustable. By setting the trajectory change unit to adjust the emission angle, the circular trajectory can be adjusted to an elliptical trajectory, and the trajectory diameter can also be increased to achieve scanning of a larger field of view. The trajectory error caused by the multi-point generation unit and the rotating scanning unit can also be compensated. In general, the scanning trajectory of the scanning system with adjustable trajectory provided by the present invention can be flexibly adjusted, which is particularly suitable for scanning in three-dimensional space, can greatly improve the scanning speed, and can realize rapid refractive surgery, etc., while meeting the needs of rapid laser scanning, refractive and astigmatism correction, and large scanning field of view in laser refractive surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic structural diagram of a scanning system with adjustable trajectory in one embodiment of the present invention;

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

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

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

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

[0041] Figure 6 FIG. 1 is a top view of a scanning trajectory of a system for correcting astigmatism in one embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] The present invention provides a scanning system with adjustable trajectory, which at least comprises a control unit and a multi-point generating unit, a rotating scanning unit and a trajectory changing unit arranged in sequence along an optical path. Figure 1 The structure diagram of the scanning system with adjustable trajectory in one embodiment of the present invention is shown, which at least includes an excitation multi-point generating unit 3, a rotation scanning unit 4, a trajectory changing unit 5, and a control unit 9. On this basis, the system can also include a light source unit 1, a focusing unit 6

[0044] The laser light source unit 1 can provide a light beam that can interact with the processed object, and the interaction includes photodisruption, photoablation, photocrosslinking, photothermal, photochemical reaction and other effects. The laser light source can be a continuous laser or a pulsed laser, and the exposure time or repetition frequency and laser energy of the laser light source can be regulated. The pulsed laser has one or several fixed and optional basic frequencies. The rapid adjustment of the repetition frequency of the pulsed laser is achieved by high-speed optical shutter frequency division. The high-speed optical shutter can be an acousto-optic modulator (AOM) or an electro-optic modulator (EOM), etc. For example, the laser light source unit 1 can be a femtosecond laser, providing a light beam 2 for subsequent processing. Specifically, the wavelength of the laser is 800nm ​​to 1500nm, the repetition frequency is 10kHz to 10MHz, and the laser power is 0.1W to 1000W.

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

[0046] The rotating scanning unit 4 can perform circular scanning of N beams of light. It should be noted that during the circular scanning process, if N>1, the N beams of light are all concentrically scanned with the same axis as the rotation center. The rotating scanning unit 4 can be a Dove prism or an Abbe-Koenig prism or three reflectors arranged in a K shape, etc. driven by a power element such as a motor.

[0047] The trajectory change unit 5 is used to synchronously increase the emission angle of the N beams of circular scanning, and the emission angle increased by each laser beam at the same time is the same, and the emission angle increased at different times is adjustable, that is, the trajectory change unit 5 can increase the scanning angle of the N beams of light in real time, synchronously, and simultaneously during the circular scanning, and the increased angles of the N beams of light are the same. The trajectory change unit 5 further adjusts the emission angle, and the circular trajectory after passing through the focusing unit 6 can be adjusted to an elliptical trajectory, and the trajectory diameter can also be increased to achieve scanning of a larger field of view, and the trajectory error caused by the multi-point generation unit and the rotation scanning unit can also be compensated. In other words, the trajectory change unit 5 may realize three functions. The first function is to realize the laser scanning trajectory transformation, modify the circular scanning trajectory to other trajectories, such as modifying the above-mentioned circular scanning trajectory to an elliptical scanning trajectory that can correct refraction and astigmatism at the same time. The second function is to expand the beam scanning angle to make up for the disadvantage that the dynamic diffraction device used in the multi-point generation unit has a small diffraction angle and cannot meet the requirements of a large scanning field of view for refractive surgery. The third function is to compensate for the scanning angle error introduced by the rotation scanning unit. Specifically, the trajectory changing unit 5 can be a device such as a galvanometer or a rotating mirror that can change the light beam exit angle.

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

[0049] The control unit 9 can calculate the scanning trajectory and synchronously control the multi-point generating unit 3, the rotating scanning unit 4, and the trajectory changing unit 5 to jointly generate one or more focused light spots and scan along the corresponding target trajectory on the processed object. Further, if N>1, the N target trajectories are concentric elliptical trajectories or concentric circular trajectories, and the N target trajectories can be located on different focusing planes, so that multi-focal refractive surgery curved trajectory scanning can be achieved, especially astigmatism correction surgery curved trajectory scanning.

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

[0051] Assuming that the rotation speed of the rotating scanning unit 4 is ω, and the incident angle of the laser incident on the rotating scanning unit 4 is α, the scanning speed of the light beam after passing through the rotating scanning unit 4 is generally 2ω, and the angle between the light beam and the optical axis is always α. When the trajectory changing unit does not perform any modulation, the scanning trajectory after passing through the focusing unit 6 is:

[0052]

[0053] Wherein, (x, y) is the coordinate of the scanning trajectory of the laser on the focusing plane, f is the focal length, θ=2ωt is the rotation angle of the light beam after passing through the rotating scanning unit 4, and at this time, the scanning trajectory is a circular trajectory. The trajectory changing unit 5 can add an angle β to the output light beam of the rotating scanning unit 4, and at this time, the scanning trajectory after focusing is:

[0054]

[0055] Since the angle α+β is small, the scanning trajectory can be approximated as:

[0056]

[0057] It can be seen from formula (3) that as long as β is adjusted in real time, the scanning trajectory can be adjusted in real time.

[0058] In one embodiment, when the trajectory changing unit 5 uses a galvanometer or a rotating mirror, the galvanometer or the rotating mirror 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 β can be continuously changed in real time with θ. The angle β is treated as a vector for orthogonal decomposition, and then

[0059]

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

[0061] like Figure 2 FIG. 1 is a schematic diagram of correcting a circular trajectory to an elliptical trajectory in one embodiment of the present invention. When the circular trajectory needs to be corrected to an elliptical trajectory, the angle adjustment component of the trajectory changing unit 5 along the X-axis direction is X. E , the angle adjustment component along the Y axis is Y E , both satisfy:

[0062]

[0063] Where A = elliptical semi-major axis minus circular radius, B = elliptical semi-minor axis minus circular radius, θ E is the angle between the major axis of the elliptical trajectory and the X axis, that is, the astigmatism axis angle in refractive surgery, and provides a signal (X E ,Y E ), the included angle β can be controlled to change into an ellipse along with the rotation angle θ, and then the circular trajectory can be corrected into an elliptical trajectory.

[0064] like Figure 3FIG. 1 is a schematic diagram of increasing the diameter of a circular trajectory in an embodiment of the present invention. When the diameter of the circular trajectory needs to be increased, the angle adjustment component of the trajectory changing unit 5 along the X-axis direction is X. A , the angle adjustment component along the Y axis is Y A , both satisfy:

[0065]

[0066] Where C is the difference in radius of the circular trajectory before and after the diameter field of view is enlarged. A signal (X) is provided to the control trajectory change unit 5. A ,Y A ), the direction of the angle β can be controlled to change in a circular shape along with the rotation angle θ, thereby increasing the diameter field of view of the circular trajectory.

[0067] The rotating scanning unit 4 may introduce a trajectory error due to manufacturing errors and installation errors. The introduced trajectory error is a circular trajectory with a scanning speed of ω, which causes the scanning trajectory to change from formula (1) to:

[0068]

[0069] Where Δα is the angle error, is the initial phase angle for error compensation.

[0070] When error compensation of the circular trajectory is required, the angle adjustment component of the trajectory change unit 5 along the X-axis direction is X. A , the angle adjustment component along the Y axis is Y A , both satisfy:

[0071]

[0072] Where E is the compensated angle error value.

[0073] Provides a signal (X) to the control trajectory change unit 5 C ,Y C ), the angle β can be controlled to compensate 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 X G , Y G The control signal can adjust the trajectory through simple calculations.

[0077] Accordingly, the present invention also relates to a scanning method, which is implemented based on the scanning system with adjustable trajectory introduced above. The method is executed by a control unit and specifically includes:

[0078] Calculate the scanning parameters required for three-dimensional processing of the object, the processing parameters including the number of focal points N of the synchronous scanning and the required target trajectory;

[0079] Divide all target trajectory contours into multiple layers and determine the scanning parameters of each layer, each layer has N target trajectories for synchronous scanning, and the target trajectories are elliptical trajectories or circular trajectories; generate the control data required by the corresponding multi-point generation unit, the rotation scanning unit and the trajectory change unit according to the scanning parameters required for scanning each layer;

[0080] The control data required for scanning the current layer is loaded to the multi-point generation unit, the rotation scanning unit and the trajectory change unit respectively to realize the scanning of the current layer scanning trajectory; when the current layer scanning is completed, the next layer is scanned until the scanning trajectory of all layers is completed.

[0081] Taking refractive surgery as an example, the following describes the processing steps for multifocal refractive surgery using the 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, number of scanning focal points N, etc. Specifically, the parameters such as the refractive power required for correction obtained from the preoperative information collection are input into the control unit 9. The control unit 9 can calculate the laser energy required for the surgery, the number of scanning focal points N, and other parameters, and calculate the tissue thickness required to be eliminated at each position through the Munnerlyn equation and the refractive power required for correction. Then the control unit 9 calculates the surgical surface according to the parameters of the system itself and generates the corresponding refractive surgery scanning trajectory; when there is astigmatism, it is also necessary to generate a scanning trajectory for correcting astigmatism according to the astigmatism of the target sample. The scanning trajectory data can be a refractive correction or an astigmatism correction or an ellipsoidal scanning trajectory that corrects both refraction and astigmatism.

[0083] 2. According to the refractive surgery scanning trajectory data, the trajectory is divided into multiple layers of scanning trajectories according to the contour lines, and each layer of scanning trajectory is N circular or elliptical trajectories. According to the scanning data of each layer, the control data required by the corresponding laser light source unit, multi-point generation unit, rotation scanning unit and trajectory change unit are generated. The control data enables each unit to cooperate to achieve the target scanning trajectory.

[0084] 3. Load or select the laser light source unit, multi-point generation unit, rotation scanning unit and trajectory change unit control data required for a certain layer of trajectory to realize the scanning of the current layer of scanning trajectory. Specifically, the control data of the multi-point generation unit can be one or more holograms. Further, the hologram can be calculated by computational holography such as GS, WSG and other algorithms. For example, the control unit 9 uses WGS, GS and other algorithms to calculate and generate one or more holograms according to the position, depth and other information in the scanning trajectory, and the hologram is used to load into the multi-point generation unit 3 to generate N beams of light that adapt to the scanning trajectory. Specifically, the control data of the rotation scanning unit can be a signal of the type of pulse, current, voltage, etc. Further, the signal contains information such as the position, rotation direction, and rotation speed of the rotation scanning unit. The control data of the trajectory change unit can be a voltage or current signal. Further, the signal can control the trajectory change unit to move or remain stationary.

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

[0086] like Figure 4 The figure shows a top view schematic diagram of multi-point scanning after focusing in an embodiment of the present invention. The scanning trajectory 70a of the previous time period is a parallel circular scan by N laser beams. The center of the circular scan is the same point, and the N beams of light perform concentric circle scanning around the rotation center. After scanning one circle, the scanning of the next time period begins, and the angle of the circular scan is changed by the trajectory changing unit 5. The trajectory scanning of the next circle is performed to obtain a scanning trajectory 71a after the scanning angle is changed. The scanning radius of the two scans is different.

[0087] like Figure 5 FIG. 1 is a schematic diagram of curved surface scanning in an embodiment of the present invention. During the annular scanning process of the light beam, the light beam is focused by the focusing unit 6 to obtain N focused light spots 7. The scanning trajectory of one circle of the focus annular scanning is N circles or ellipses. Figure 3 As shown, the positions of the lasers at different positions on the curved surface scanning trajectory 70b before the scanning angle is changed in the axial direction of the processing target sample are not the same after focusing, but are located on a curved surface. The circular scanning is performed by the rotating scanning unit 4, and the scanning angle is changed by the trajectory changing unit 5. The next circle of scanning is performed to obtain the curved surface scanning trajectory 71b after the scanning angle is changed. After multiple circles of scanning, the curved surface scanning trajectory is finally realized on the processing target sample 8.

[0088] like Figure 6 FIG. 1 is a top view of the scanning trajectory of the system for correcting astigmatism in one embodiment of the present invention. Figure 4As shown, when the rotating scanning unit 4 is directly used for circular scanning, the top view of the scanning trajectory obtained is a perfect circle, which cannot achieve the purpose of correcting astigmatism. Therefore, while performing the circular scanning, it is necessary to synchronously control the trajectory change unit 5 to change the scanning angle of different positions in a circle of scanning in real time, so as to change the circular scanning trajectory into an elliptical scanning trajectory.

[0089] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. It should be noted that "in one embodiment", "for example", "for example", etc. of the present invention are intended to illustrate the present invention, rather than to limit the present invention.

[0090] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A scanning system with adjustable trajectory, characterized in that: It includes a control unit and a multi-point generating unit, a rotating scanning unit and a trajectory changing unit arranged in sequence along the optical path, wherein: The multi-point generating unit is used to split the incident laser into N beams, and the number of split beams is adjustable; The rotating scanning unit is used to make the N light beams synchronously scan circular trajectories; The trajectory changing unit is used to synchronously increase the emission angles of the N light beams of the circular scanning, and the emission angles of each light beam increased at the same time are the same, and the emission angles increased at different times are adjustable; After the N light beams emitted by the trajectory changing unit are focused, they form N focused light spots that act on the processed object and simultaneously scan N target trajectories, wherein the N target trajectories are elliptical trajectories or circular trajectories; The control unit is used to control the multi-point generating unit, the rotating scanning unit and the trajectory changing unit according to the required target trajectory, so that N focused light spots are synchronously scanned along the corresponding target trajectory on the processing object.

2. The scanning system with adjustable trajectory as claimed in claim 1, characterized in that: The trajectory changing unit is a galvanometer or a rotating mirror.

3. The scanning system with adjustable trajectory as claimed in claim 2, characterized in that: The track change 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 track change unit along the X-axis direction and along the X-axis direction are respectively X and Y. G , Y G , X G , Y G satisfy: Where, X E , Y E They are the angle adjustment component along the X-axis direction and the angle adjustment component along the Y-axis direction when the circular trajectory needs to be corrected to an elliptical trajectory. E , Y E satisfy: Where A = the semi-major axis of the corrected elliptical trajectory minus the radius of the circular trajectory before correction, B = the semi-minor axis of the corrected elliptical trajectory minus the radius of the circular trajectory before correction, θ is the rotation angle of the beam after the rotating scanning unit, θ E is the angle between the major axis of the elliptical trajectory and the X-axis; X A , Y A They are the angle adjustment component along the X-axis direction and the angle adjustment component along the Y-axis direction when the diameter of the circular track needs to be increased. A , Y A satisfy: Where C is the difference in radius of the circular trajectory before and after the diameter field is enlarged; X A , Y A They are the angle adjustment component along the X-axis direction and the angle adjustment component along the Y-axis direction when error compensation of the circular trajectory is required. A , Y A satisfy: Where E is the angle error value compensated, is the initial phase angle for error compensation.

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

5. The scanning system with adjustable trajectory as claimed in claim 4, characterized in that: The N target tracks are located on different focusing planes.

6. The scanning system with adjustable trajectory as claimed in claim 1, characterized in that: The multi-point generating unit is a digital micromirror device or a liquid crystal spatial light modulator, and the multi-point generating unit realizes intensity or phase modulation of the light beam by loading or switching a hologram.

7. The scanning system with adjustable trajectory as claimed in claim 1, characterized in that: The rotating scanning unit is a Dove prism or an Abbe-Koenig prism or three reflectors arranged in a K shape driven by a power element.

8. The scanning system with adjustable trajectory as claimed in claim 1, characterized in that: The scanning system further includes a focusing unit, which is used to focus the N light beams emitted by the trajectory changing unit.

9. The scanning system with adjustable trajectory as claimed in claim 1, characterized in that: The system is used in corneal refractive surgery.

10. A scanning method with adjustable trajectory, characterized in that: Based on the scanning system with adjustable trajectory according to any one of claims 1 to 9, the method is executed by a control unit, and the method comprises: Calculating scanning parameters required for three-dimensional processing of the object, wherein the processing parameters include the number of focal points N of synchronous scanning and the required target trajectory; Divide all target trajectory contours into multiple layers and determine the scanning parameters of each layer, each layer having N target trajectories for synchronous scanning, wherein the target trajectories are elliptical trajectories or circular trajectories; generate control data required by the corresponding multi-point generation unit, the rotation scanning unit and the trajectory change unit according to the scanning parameters required for scanning each layer; The control data required for scanning the current layer is loaded to the multi-point generation unit, the rotation scanning unit and the trajectory change unit respectively to realize the scanning of the current layer scanning trajectory; when the current layer scanning is completed, the next layer is scanned until the scanning trajectory of all layers is completed.

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