Five-axis galvanometer laser processing method and processing device

Abstract

The application provides a five-axis galvanometer laser processing method and a processing device, which realizes decoupling control of five-axis positions and postures of a laser beam and a focal point position based on a pure optical method, and multi-degree-of-freedom processing can be completed without mechanical movement or rotation axes; the processing device comprises a dynamic focusing system, a beam position and posture adjusting system and a focusing optical element; the dynamic focusing system adjusts a laser beam divergence angle to control an axial position of a focal point; the beam position and posture adjusting system adjusts a beam space position and an incident angle by rotating a multi-plane mirror; based on a beam space vector control model and an inverse solving algorithm, the focal point position and the incident posture are cooperatively and decoupled controlled; a paraxial imaging system realizes real-time observation of a processing process and online measurement of micro-hole depth and morphology, and self-adaptive closed-loop feedback is realized by combining a nonlinear regression algorithm, dynamic performance of the system is significantly improved, accuracy of processing positions and postures is ensured, and an efficient solution is provided for laser processing of microstructures and complex curved surfaces.

Description

Technical Field

[0001] This application relates to laser processing technology, and more particularly to a five-axis galvanometer laser processing method and processing apparatus. Background Technology

[0002] Laser processing, with its advantages of high energy density and non-contact processing, is widely used in fields such as micro-hole processing, precision cutting, and complex structure manufacturing. The rapid development of industries such as aerospace, electronic packaging, and composite materials has led to a continuous increase in the demand for processing complex spatial structures such as tilted holes and high aspect ratio micro-holes. Traditional two-dimensional or three-axis laser processing methods are no longer sufficient to meet the requirements of processing accuracy and spatial freedom for complex structures.

[0003] Existing multi-axis laser processing solutions mostly rely on mechanical axes and rotary tables to adjust the beam attitude. However, these solutions generally suffer from problems such as complex structure, large system inertia, slow dynamic response, and significant accumulated mechanical errors, making it difficult to guarantee processing stability and repeatability in high-speed micromachining scenarios. Although some solutions incorporate galvanometer systems to achieve high-speed beam scanning and optimize processing performance with optical components, most galvanometer devices only support planar scanning or small-angle deflection, and cannot precisely control the beam focal position and incident tilt angle. Focus drift is prone to occur during tilted processing, severely reducing the consistency of micro-hole shape, and defects are more pronounced in high aspect ratio processing.

[0004] Meanwhile, existing coaxial imaging monitoring methods have weak anti-interference capabilities. Under high-speed deflection and tilting processing conditions, they are easily affected by field-of-view shaking and stray light interference, making it difficult to accurately detect the depth and morphology of microholes and achieve closed-loop control of the processing process. Therefore, there is an urgent need to develop a galvanometer laser processing method without a mechanical feed axis, capable of coordinated control of the five-axis position, attitude, and focal position of the laser beam, and possessing stable observation capabilities, in order to improve the accuracy and stability of complex microstructure processing. Summary of the Invention

[0005] In view of the problems of complex mechanical axis structure, limited dynamic response, and serious focus drift in tilting machining in the prior art, the main technical problem to be solved by the present invention is to provide a five-axis galvanometer laser machining method and machining device, which realizes the coordinated control of the five-axis position and attitude of the laser beam and the focus position through pure optical means, and can realize multi-degree-of-freedom machining without mechanical feed axis.

[0006] To address the aforementioned technical problems, this application provides a five-axis galvanometer laser processing method, employing the following technical solution:

[0007] A five-axis galvanometer laser processing method is disclosed. The method employs a five-axis galvanometer laser processing system, wherein the five axes include the X, Y, and Z axes coordinates of the target focal point within the processing area, and the incident tilt angle of the laser beam within the processing area. , , Let be the angle between the projection of the laser beam onto the XOZ plane and the Z-axis. Let be the angle between the projection of the laser beam onto the YOZ plane and the Z-axis;

[0008] A convex lens and a concave lens are arranged along the laser beam emission direction. The concave lens can reciprocate by moving closer to or further away from the convex lens along the optical axis of the laser beam to adjust the coordinates of the target focus on the Z-axis.

[0009] When the concave lens is in its initial position, the distance between the concave lens and the convex lens is , Let be the focal length of the concave lens. The focal length of the convex lens; the laser beam divergence angle. Based on the movement of the concave lens, we can obtain:

[0010] Focal plane position of focusing optical element ,in To focus the effective focal length of the optical element, This is the distance between the convex lens and the focusing optical element. The moving distance of the concave lens is used to focus the optical element to convert the laser beam into a multi-dimensional vector landing point on the processing plane;

[0011] Z-axis displacement in the focal plane ,in For when The position of the focal plane;

[0012] Multiple rotatable plane mirrors are arranged on the exit side of the concave lens. By coordinating the rotation of these multiple plane mirrors, the X-axis and Y-axis coordinates and the incident tilt angle of the laser beam are determined. , By adjusting the parameters, we can obtain:

[0013] laser beam through the first The propagation direction unit vector after the plane mirror is deflected ,in, For the first A spatial rotation matrix determined by the deflection angle of a plane mirror. For the first The propagation direction unit vector after the second reflection;

[0014] The unit vector of the propagation direction of the laser beam after being deflected by multiple plane mirrors ,in, For the first The deflection angle parameters of a plane mirror The initial propagation direction is the unit vector;

[0015] After propagation through multiple plane mirrors, the position vector of the laser beam at the focal plane of the focusing optics is: ,in, Let be the initial position vector of the incident laser beam. The number of plane mirrors. The first parameter is set based on the distance between adjacent plane mirrors or the distance between the mirror and the focusing optical element. The propagation length of the optical path;

[0016] The processing method includes the following steps:

[0017] S1. Target Trajectory Analysis and Reverse Solving: Based on the preset complex surface machining trajectory, determine the three-dimensional coordinate vector of the target focus within the machining area and the incident attitude parameters. And based on the beam space vector control model, Converted into a unit vector of the propagation direction at the incident focal plane of the focusing optical element. Position vector and focal plane position ;

[0018] The system of linear equations is established as follows: The distance the concave lens moved was calculated using a numerical algorithm in reverse engineering. and the deflection angle parameters of each plane mirror. ;

[0019] S2, Focal plane preset adjustment: Control the concave lens to move first, according to the calculated moving distance. The divergence angle of the laser beam is modulated to match the target focal depth, thereby achieving pre-positioning in the Z-axis dimension;

[0020] S3. Spatial Vector Coordinated Deflection: Based on the concave lens, control the multiple plane mirrors to work in tandem, according to the solved deflection angle parameters. Generate the corresponding X-axis, Y-axis coordinates and incident tilt angle. , The laser beam is focused onto the processing area by a focusing optical element and in a specific orientation.

[0021] In a preferred embodiment: four rotatable plane mirrors are provided on the exit side of the concave lens, wherein the first plane mirror and the third plane mirror rotate together to change the parallel displacement of the laser beam relative to the X-axis direction of the laser beam exit optical axis, and the equivalent spatial rotation matrix is: The second and fourth plane mirrors rotate in tandem, altering the parallel displacement of the laser beam relative to its output optical axis along the Y-axis. The equivalent spatial rotation matrix is: We can obtain:

[0022] ;

[0023] ;

[0024] The unit vector of the propagation direction of the laser beam after being deflected by four plane mirrors ,in, , , and These represent the deflection angles of the first, second, third, and fourth plane mirrors, respectively. , Substitute into the formula , , Substitute into the formula ;

[0025] Based on the recursive relationship of the laser beam's direction at each reflector and its positional relationship in adjacent propagation segments, a system derived from the reflector deflection angle parameters can be established. Corresponding optical path propagation length Position vector to the focal plane of the focusing optical element and propagation direction unit vector Unified forward mapping function ,Right now: , It is the distance between the first and second reflecting mirrors. It is the distance between the second and third reflecting mirrors. It is the distance between the third and fourth reflecting mirrors. It is the distance between the fourth reflecting mirror and the focusing optical element.

[0026] In a preferred embodiment: In step S1 of the processing method, the laser beam, which has been controlled by a concave lens and a plane mirror, is focused onto the processing area by the focusing optical element. The three-dimensional coordinate vector of the focal point and the incident attitude parameters of the focused laser beam within the processing area are then determined. ,in, The coordinates of the laser beam on the focal plane of the focusing optics are the X, Y, and Z axes. Let be the angle between the projection of the laser beam onto the XOZ plane and the Z-axis. Let be the angle between the projection of the laser beam onto the YOZ plane and the Z-axis;

[0027] In the beam space vector control model, when a laser beam enters the focusing optical element with different exit directions, the focusing optical element will converge the incoming laser beam to different points on its focal plane. Based on the definitions of the X, Y, and Z axes, the propagation direction unit vector can be obtained. ;

[0028] The coordinates of the X, Y, and Z axes on the focal plane are:

[0029] ;

[0030] ;

[0031] ;

[0032] When the position vector at the focal plane of the laser beam is changed At different times, the degree of refraction of the laser beam varies, thus changing the incident angle of the laser beam when it reaches the workpiece. Based on the definitions of the X, Y, and Z axes, the position vector can be obtained. According to the definition, the entrance pupil position of the laser beam entering the focusing optical element can be obtained. for The included angle of the laser beam is:

[0033] .

[0034] in This is the nonlinear angle compensation term caused by the laser beam propagation direction vector.

[0035] In a preferred embodiment: the processing method further includes step S4, topography monitoring and adaptive closed loop: the processing image feature parameters are extracted in real time through the paraxial imaging system, the actual processing depth and topography error are inverted, and they are used as compensation constraints to dynamically close the loop to correct the focal position and incident tilt angle;

[0036] The specific process is as follows:

[0037] Based on the mapping relationship between image pixel coordinates and actual spatial displacement obtained by the paraxial imaging system, the current actual processing depth is quantitatively inverted. ;

[0038] Calculate the actual machining depth measured in real time With the preset target hole depth Deviation between ;

[0039] Deviation Feedback is sent to the beam space vector control model to trigger the deflection angle parameters of each planar mirror. and the distance the concave lens moves The quadratic nonlinear regression solution is used to adaptively compensate for the errors of the concave lens and the plurality of plane mirrors.

[0040] In a preferred embodiment: the imaging optical path of the paraxial imaging system is independent of the laser processing optical path, and is used to observe the laser processing process in real time;

[0041] The rangefinder imaging system includes a CCD camera and an imaging objective lens. The observation field of the rangefinder imaging system is decoupled from the action of the beam pose adjustment system to maintain a steady-state observation relative to the processing area.

[0042] The off-axis imaging system is used to measure the depth and morphology of the processed micro-holes in the processing area in real time; let the coordinates of the micro-hole opening at the center of the imaging image be... The coordinates of the bottom of the micropore at the center of the imaging image are: Then the pixel offsets of the two in the imaging image plane are respectively ;

[0043] By calibrating the paraxial imaging system, a proportional mapping relationship between image pixel coordinates and actual spatial displacement is established, with the horizontal and vertical scale coefficients set as follows: and The corresponding actual displacement component is ;

[0044] Let the angle between the line of sight of the off-axis imaging system and the normal to the workpiece surface be . The azimuth angle of the projection of the viewing axis into the workpiece plane is The depth of the hole This can be expressed as a function of the projection of the image displacement onto the observation direction and the angle between the projection and the observation direction, i.e. .

[0045] In a preferred embodiment: when the machined hole is an inclined hole, let the unit vector of the hole axis direction be... ;

[0046] in, and Let represent the inclination angle of the hole axis relative to the workpiece normal and its azimuth angle in the workpiece plane, respectively; let the image displacement vector be . The paraxial imaging projection matrix is The hole depth is then expressed as .

[0047] To address the aforementioned technical problems, this application also provides a five-axis galvanometer laser processing apparatus, employing the following technical solution:

[0048] A five-axis galvanometer laser processing apparatus is used to implement the five-axis galvanometer laser processing method described above. The galvanometer laser processing apparatus is arranged in sequence along the laser propagation direction, including a dynamic focusing system, a beam pose adjustment system, a focusing optical element, and a paraxial imaging system.

[0049] The dynamic focusing system is used to modulate the divergence angle of the laser beam. The dynamic focusing system includes a concave lens and a convex lens. The concave lens can reciprocate by moving closer to or further away from the convex lens along the optical axis of the laser beam.

[0050] The beam pose adjustment system includes multiple rotatable plane mirrors. By coordinating the rotation of the multiple plane mirrors, the spatial position and incident tilt angle of the laser beam can be controlled.

[0051] The focusing optical element is used to convert the laser beam into a multi-dimensional vector landing point on the processing plane; the imaging optical path of the paraxial imaging system is independent of the laser processing optical path and is used to observe the laser processing process in real time.

[0052] In a preferred embodiment: the dynamic focusing system further includes a high-frequency vibration device and a fixing element; the high-frequency vibration device includes a voice coil motor, which drives the concave lens to reciprocate along the optical axis of the laser emission; the fixing element is used to fix the convex lens; the concave lens and the convex lens are arranged sequentially along the optical axis of the laser emission.

[0053] In a preferred embodiment: the focusing optical element is a telecentric focusing optical system, used to convert the incoming laser beam into a multi-dimensional vector landing point on the processing plane; the propagation direction of the laser beam is a unit vector. Used to determine the spatial coordinates of the laser focus on the focal plane; the position vector of the laser beam at the incident focal plane of the focusing optical element. Used to adjust the converging attitude of a laser beam after it has been refracted by a focusing optical element;

[0054] The rangefinder imaging system includes a CCD camera and an imaging objective lens. The observation field of view of the rangefinder imaging system is decoupled from the action of the beam pose adjustment system to maintain steady-state observation relative to the processing area. The rangefinder imaging system can be arranged vertically for positioning the processing focal plane, or arranged at an angle for real-time observation of the processing process.

[0055] In a preferred embodiment: the beam pose adjustment system includes four rotatable plane mirrors and a drive unit for driving the rotation of a single plane mirror, the drive unit including a servo motor or a galvanometer motor;

[0056] The four plane mirrors include a first plane mirror, a second plane mirror, a third plane mirror, and a fourth plane mirror;

[0057] The first planar reflector is positioned behind the convex lens along the optical axis of the laser beam to reflect the laser beam emitted from the convex lens; the second planar reflector is positioned on the reflection path of the first planar reflector; the third planar reflector is positioned on the reflection path of the second planar reflector; and the fourth planar reflector is positioned on the reflection path of the third planar reflector.

[0058] The first and third plane mirrors rotate together to control the amount of parallel displacement of the laser beam relative to the X-axis direction of the laser beam emission axis; the second and fourth plane mirrors rotate together to control the amount of parallel displacement of the laser beam relative to the Y-axis direction of the laser beam emission axis.

[0059] The third and fourth plane mirrors rotate in coordination to adjust the incident angle of the laser beam into the focusing optical element.

[0060] In summary, this application has the following beneficial effects:

[0061] 1. This invention uses a purely optical method to achieve coordinated control of the five-axis position and attitude of the laser beam and the focal position. It can realize multi-degree-of-freedom laser processing without mechanical feed axes or rotary platforms, significantly reducing the complexity of the system structure and mechanical inertia, and improving dynamic response performance.

[0062] 2. By placing the dynamic focusing system in front of the beam pose adjustment system, the laser beam completes the pre-adjustment of the focal axis position before spatial deflection, realizing the decoupled control of the focal position and the five-axis position and attitude, effectively suppressing the focal drift during tilting processing, and improving processing accuracy and hole shape consistency.

[0063] 3. A beam pose adjustment system is constructed based on the coordinated rotation of multiple reflectors. Combined with the beam space vector control model, the independent control and unified modeling of the laser beam translation displacement and incident tilt angle are realized, which enhances the control linearity and solvability, and facilitates the accurate planning and execution of complex processing trajectories.

[0064] 4. Based on the aforementioned beam space vector control model and inverse solution algorithm, a rapid mapping from the target processing pose to the system control parameters is achieved, thereby improving the control accuracy and execution efficiency of multi-degree-of-freedom laser processing.

[0065] 5. A paraxial imaging system is adopted to make its observation optical path independent of the laser processing optical path, avoiding field of view sway and imaging distortion caused by coaxial imaging under conditions of high-speed mirror deflection and tilted processing, thus ensuring stable observation of the processing area.

[0066] 6. Based on real-time measurement data from the off-axis imaging system, an adaptive closed-loop feedback mechanism is constructed using a nonlinear regression algorithm to dynamically compensate for machining depth and shape errors, thereby further improving machining accuracy, stability, and consistency.

[0067] 7. This invention achieves coordinated dynamic control of the laser beam focal position and incident tilt angle, and is suitable for high-difficulty processing scenarios such as tilted micro-holes, high aspect ratio structures and complex curved surfaces, and has good engineering application prospects. Attached Figure Description

[0068] Figure 1 A flowchart illustrating the galvanometer laser processing method of the first embodiment;

[0069] Figure 2 A schematic diagram of the overall structure of the galvanometer laser processing device in the second embodiment;

[0070] Figure 3 A comparison diagram of the advantages of front-mounted dynamic focusing in the second embodiment (where Figure (a) represents the traditional dynamic focusing diagram and Figure (b) represents the dynamic focusing diagram of this embodiment).

[0071] Figure 4 A schematic diagram of the structure and operation of the beam pose adjustment system in the second embodiment;

[0072] Figure 5 Schematic diagram of the spatial vector control principle of the galvanometer laser beam in the second embodiment;

[0073] Figure 6 Schematic diagram of the telecentric focusing optical system in the second embodiment;

[0074] Figure 7 Schematic diagram of the decoupling relationship between the off-axis imaging system and the laser processing optical path in the second embodiment;

[0075] Figure 8 The second embodiment shows the machining effect of the negative cone hole.

[0076] Explanation of reference numerals in the attached drawings: 1. Dynamic focusing system; 11. Concave lens; 12. Convex lens; 13. High-frequency vibration device; 14. Fixing element; 2. Beam pose adjustment system; 21. First plane mirror; 22. Second plane mirror; 23. Third plane mirror; 24. Fourth plane mirror; 25. First rotating device; 26. Second rotating device; 27. Third rotating device; 28. Fourth rotating device; 3. Focusing optical element; 4. Rangefinder imaging system; 41. CCD camera; 42. Imaging objective lens; 5. Workpiece. Detailed Implementation

[0077] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0078] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," 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" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0079] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed", "equipped", "sleeved / connected", "connected", etc., should be interpreted broadly. For example, "connection" can be a wall-mounted connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0080] First Embodiment

[0081] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0082] This application provides a five-axis galvanometer laser processing method. The method employs a five-axis galvanometer laser processing system, where the five axes include the X, Y, and Z axes coordinates of the target focal point within the processing area, and the incident tilt angle of the laser beam within the processing area. , , Let be the angle between the projection of the laser beam onto the XOZ plane and the Z-axis. Let be the angle between the projection of the laser beam onto the YOZ plane and the Z-axis.

[0083] The processing method includes the following steps:

[0084] S1. Target Trajectory Analysis and Reverse Solving: Based on the preset complex surface machining trajectory, determine the three-dimensional coordinate vector of the target focus within the machining area and the incident attitude parameters. Based on the beam space vector control model, the moving distance of the concave lens 11 in the dynamic focusing system 1 is solved in reverse using a numerical algorithm. And the deflection angle parameters of each plane mirror in the beam pose adjustment system 2 ;

[0085] S2, Focal plane preset adjustment: Control the dynamic focusing system 1 to move first, according to the calculated moving distance. The divergence angle of the laser beam is modulated to match the target focal depth, thereby achieving pre-positioning in the Z-axis dimension;

[0086] S3. Spatial Vector Cooperative Deflection: Based on the control of the dynamic focusing system 1, the four planar mirrors of the beam pose adjustment system 2 are controlled in tandem, according to the solved deflection angle parameters. Generate the corresponding X-axis, Y-axis coordinates and incident tilt angle. , The laser beam is focused onto the processing area via focusing optical element 3 and in a specific orientation;

[0087] In S3, the space vector cooperative deflection also includes decoupling and energy compensation control for complex surface machining. The specific process is as follows:

[0088] By decoupling the focus height adjustment of the dynamic focusing system 1 and the spatial vector adjustment of the beam pose adjustment system 2 in the time sequence, nonlinear coupling errors in the multi-axis linkage process are suppressed.

[0089] And in executing the deflection angle parameters At that time, the position vector of the laser beam entering the entrance pupil of the focusing optical element 3 is dynamically adjusted. Actively control the actual incident angle of the laser beam to reach the surface of workpiece 5 in order to achieve spot energy compensation during the processing of complex curved surfaces with varying incident angles.

[0090] S4. Topography monitoring and adaptive closed-loop: The feature parameters of the processing image are extracted in real time by the off-axis imaging system 4, the actual processing depth and topography error are inverted, and they are used as compensation constraints to dynamically correct the focal position and incident tilt angle in a closed loop.

[0091] In S4, when the CCD camera 41 detects the actual hole depth Less than the target depth And deviation When the distance exceeds a preset threshold (e.g., 5μm), the control system performs inverse calculations based on the beam space vector control model, and adjusts the pulse width of the drive current of the voice coil motor in real time to finely adjust the moving distance of the concave lens 11. This allows for in-situ depth compensation during the processing, eliminating the need for machine downtime for inspection.

[0092] The specific process is as follows:

[0093] Based on the mapping relationship between image pixel coordinates and actual spatial displacement obtained by the paraxial imaging system 4, the current actual processing depth is quantitatively inverted. ;

[0094] Calculate the actual machining depth measured in real time With the preset target hole depth Deviation between ;

[0095] Deviation Feedback is sent to the beam space vector control model to trigger the deflection angle parameters of each reflector. and the moving distance of concave lens 11 The quadratic nonlinear regression solution is used to adaptively compensate for errors in the dynamic focusing system 1 and the beam pose adjustment system 2.

[0096] Second Embodiment

[0097] The following is in conjunction with the appendix Figures 2-8 This application will be described in further detail.

[0098] Based on the galvanometer laser processing method provided in the first embodiment, this application provides a five-axis galvanometer laser processing apparatus, which adopts the following technical solution:

[0099] The processing device controls the five-axis position, attitude, and focal position of the laser beam using optical methods, achieving multi-degree-of-freedom laser processing without introducing mechanical movement or rotation axes. The processing device includes a dynamic focusing system 1, a beam attitude adjustment system 2, a focusing optical element 3, and a paraxial imaging system 4, arranged sequentially along the laser propagation direction. The processing device receives the laser beam emitted from the laser emitting device and, through the dynamic focusing system 1, beam attitude adjustment system 2, and focusing optical element 3, ultimately applies the laser beam to the surface of the workpiece 5. Simultaneously, the paraxial imaging system 4 is positioned on one side of the processing area for real-time observation of the laser processing process. Wherein:

[0100] The dynamic focusing system 1 is used to dynamically adjust the focal height of the laser beam by modulating the divergence angle of the laser beam before the laser beam enters the beam pose adjustment system 2, that is, the Z-axis dimension of the five-axis dimension.

[0101] The dynamic focusing system 1 includes a concave lens 11 and a convex lens 12. The concave lens 11 can reciprocate by moving closer to or further away from the convex lens 12 along the optical axis of the laser emission. The dynamic focusing system 1 also includes a high-frequency vibration device 13 and a fixing element 14. The high-frequency vibration device 13 includes a voice coil motor, which drives the concave lens 11 to reciprocate along the optical axis of the laser emission. The fixing element 14 is used to fix the convex lens 12. The concave lens 11 and the convex lens 12 are arranged sequentially along the optical axis of the laser emission.

[0102] Specifically, such as Figure 1 The concave lens 11 is disposed on the optical axis from which the laser is emitted. One side of the lens is connected to the high-frequency vibration device 13, and the other side is disposed opposite to the convex lens 12. The convex lens 12 is fixed in a preset position by a fixing element 14 to define the reference optical axis of the optical system.

[0103] In this embodiment, the high-frequency vibration device is preferably a voice coil motor, whose output end is rigidly connected to the concave lens 11. By applying different driving currents to the voice coil motor, the concave lens 11 can be controlled to perform high-frequency, short-stroke reciprocating motion along the laser optical axis. The change in position of the concave lens 11 will cause a dynamic change in the laser beam divergence angle, thereby changing the equivalent focal length of the laser beam and realizing the rapid movement of the laser focus along the optical axis.

[0104] The dynamic focusing system 1 is used to modulate the divergence angle and Z-axis displacement of the laser beam, as follows:

[0105] The focal length of the concave lens 11 is set to The focal length of the convex lens 12 is set to The diameter of the incident parallel laser beam is set to The moving distance of the concave lens 11 is set as The distance between the convex lens 12 and the focusing optical element 3 is set to... The effective focal length of the focusing optical element 3 is set to ;

[0106] When the concave lens 11 is in its initial position, the distance between the concave lens 11 and the convex lens 12 is laser beam divergence angle We can obtain:

[0107] The diameter of the laser beam emitted through the convex lens 12 is The focal plane position of focusing optical element 3 ;

[0108] Z-axis displacement in the focal plane Among them For when The position of the focal plane.

[0109] In this embodiment, the focal length of the concave lens 11 The focal length of convex lens 12 is selected to be between -20mm and -50mm. The selected range is between 50mm and 100mm. The vibration frequency of the high-frequency vibration device is set between 50Hz and 500Hz, and its reciprocating distance is precisely controlled. (For example, within ±5mm range), the focus can be dynamically adjusted to a range of more than 4mm in the Z-axis direction, and the response time reaches the microsecond level.

[0110] Because the dynamic focusing system 1 is positioned before the beam pose adjustment system 2, the laser beam has already completed divergence angle modulation and focus height preset before entering the subsequent mirror system, thus avoiding aberration amplification and focus drift problems caused by focusing in a tilted beam state. At the same time, this pre-focusing method reduces the optical aperture requirement of the subsequent system, which helps to reduce the moment of inertia of the galvanometer system and improve the response speed.

[0111] like Figure 3 As shown in (a), traditional five-axis machining often involves focusing after deflection. Since the beam is already at a large angle of inclination, moving the focusing lens introduces severe spherical aberration and coma. Figure 3 As shown in (b), this embodiment uses a sequential control strategy of first presetting the focal length and then adjusting the pose to ensure that the laser beam always enters the pose adjustment unit in a collimated or preset convergent state, thus ensuring that the roundness of the focal spot remains above 90% during large tilt angle processing and avoiding energy distribution distortion.

[0112] like Figure 1 , Figure 3 The beam pose adjustment system 2 includes four plane mirrors and corresponding drive units that drive the rotation of each plane mirror. The four plane mirrors rotate in tandem to determine the X-axis and Y-axis coordinates and incident tilt angle of the laser beam before it enters the focusing optical element 3. , To implement regulation.

[0113] A beam space vector control model is established based on the rotation angle parameters of the four planar mirrors and the mirror spacing parameters of adjacent planar mirrors; the initial position vector of the incident laser beam is set as follows. The initial propagation direction unit vector is , No. The deflection angle parameters of the plane mirrors are as follows: ;

[0114] Then the laser beam passes through the first The propagation direction unit vector after the plane mirror is deflected ,in, For the first A spatial rotation matrix determined by the deflection angle of a plane mirror. For the first The propagation direction unit vector after the second reflection;

[0115] The unit vector of the propagation direction of the laser beam after being deflected by multiple plane mirrors ,in, For the first The deflection angle parameters of a plane mirror The initial propagation direction is the unit vector;

[0116] The deflection of each plane mirror can be equivalently represented as a rotational transformation about orthogonal coordinate axes. The four plane mirrors include a first plane mirror 21, a second plane mirror 22, a third plane mirror 23, and a fourth plane mirror 24. The first plane mirror 21 and the third plane mirror 23 rotate collaboratively to control the parallel displacement of the laser beam relative to the X-axis direction of the laser beam's output optical axis. The equivalent spatial rotation matrix is: The second plane mirror 22 and the fourth plane mirror 24 rotate together to control the parallel displacement of the laser beam relative to the Y-axis direction of the laser beam's output optical axis. The equivalent spatial rotation matrix is: We can obtain:

[0117] ;

[0118] ;

[0119] The four plane mirrors correspond to , Substituting into the formula, we can obtain the unit vector of the laser beam's propagation direction after being deflected by the four plane mirrors. ,in, , , and These represent the deflection angles of the first, second, third, and fourth plane mirrors, respectively. , Substitute into the formula , , Substitute into the formula ;

[0120] Based on the inter-mirror spacing parameter between adjacent plane mirrors or the distance parameter between the mirror and the focusing optical element, let the first... The propagation length of the optical path is Then the position vector of the beam after propagation in this segment satisfies ;

[0121] Therefore, after multiple deflections and propagations, the position vector of the laser beam at the incident focal plane of the focusing optical element 3 is: ,in, Let be the initial position vector of the incident laser beam. The number of plane mirrors;

[0122] Based on the recursive relationship of the laser beam's direction at each planar mirror and its positional recursive relationship in adjacent propagation segments, a system derived from the mirror deflection angle parameters can be established. and the corresponding propagation segment length Position vector to the focal plane of the focusing optical element and propagation direction unit vector Unified forward mapping function ;

[0123] Regarding the position and direction of the laser beam before entering the focusing optical element 3, the unified mapping relationship between the rotation angle of the plane mirror, the corresponding propagation segment length, and the spatial position of the laser beam is as follows (substituting...). and The formula (from which the final calculation yields the following result) is as follows:

[0124] ;

[0125] in, It is the distance between the first and second reflecting mirrors. It is the distance between the second and third reflecting mirrors. It is the distance between the third and fourth reflecting mirrors. It is the distance between the fourth reflecting mirror and the focusing optical element;

[0126] The mapping function It is constructed by superimposing a spatial rotation matrix and a free propagation vector. In this embodiment, as... Figure 3 The drive unit includes four rotating devices: a first rotating device 25, a second rotating device 26, a third rotating device 27, and a fourth rotating device 28. Each rotating device drives a corresponding plane mirror to rotate around a fixed axis; the rotating device includes a servo motor or a galvanometer motor.

[0127] A first planar reflector 21, positioned behind the convex lens 12 along the optical axis of the laser beam, reflects the laser beam emitted from the convex lens 12. A second planar reflector 22 is positioned along the reflection path of the first planar reflector 21, a third planar reflector 23 is positioned along the reflection path of the second planar reflector 22, and a fourth planar reflector 24 is positioned along the reflection path of the third planar reflector 23. The third planar reflector 23 and the fourth planar reflector 24 rotate together to adjust the incident angle of the laser beam entering the focusing optical element 3.

[0128] Specifically, when it is necessary to generate the spatial position of the laser beam (i.e., the parallel displacement of the X and Y axes within the focal plane) without changing the incident tilt angle, the drive device controls the first plane mirror 21 and the third plane mirror 23 to rotate synchronously in opposite directions at the same angle (or in a specific proportional relationship), canceling out the angular deflection and retaining only the displacement vector; when it is necessary to adjust the incident tilt angle entering the focusing optical element 3, the focus is on adjusting the deflection angle of the third plane mirror 23 and the fourth plane mirror 24. Through this four-mirror linkage spatial vector mapping, the system realizes the position coordinates in five-axis machining. With attitude angle , Complete physical projection decoupling.

[0129] The aforementioned mirror combination achieves decoupled control between laser beam parallel displacement adjustment and incident tilt angle adjustment. The parallel displacement and incident tilt angle are independently controlled by adjusting the laser beam's spatial vector, thus forming... Figure 4 Galvanometer laser processing capability.

[0130] like Figure 1 , Figure 5 The focusing optical element 3 is a telecentric focusing optical system used to stably focus laser beams with different parallel displacements and different incident tilt angles after being modulated by the beam pose adjustment system 2 onto the processing area, converting the incoming laser beam into a multi-dimensional vector landing point on the processing plane, wherein the propagation direction of the laser beam is a unit vector. Used to determine the spatial coordinates of the laser focus on the focal plane, achieving precise positioning of the processing location; the position vector of the laser beam at the focal plane of the focusing optical element 3. It is used to adjust the convergence attitude of the laser beam after refraction by focusing optical element 3, and to achieve energy compensation of the laser spot for processing complex curved surfaces by actively controlling the incident tilt angle during processing.

[0131] By using telecentric focusing, focusing errors at different scanning positions and incident angles can be reduced, ensuring that the energy distribution of the laser beam on the processing plane remains consistent, thereby improving the stability of tilting and multi-dimensional vector processing.

[0132] The focusing optical element 3 is used to focus the laser beam, which has passed through the dynamic focusing system 1 and the beam pose adjustment system 2, onto the processing area. After focusing, the focal space coordinates and incident attitude parameters of the laser beam within the processing area are obtained. ,in, The coordinates of the laser beam on the focal plane of the focusing optics are the X, Y, and Z axes. Let be the angle between the projection of the laser beam onto the XOZ plane and the Z-axis. Let be the angle between the projection of the laser beam onto the YOZ plane and the Z-axis; The focal space coordinates and incident attitude parameters of the focused laser beam within the processing area are used to define the beam space vector control model in reverse.

[0133] In the beam space vector control model, when a laser beam enters the focusing optical element 3 with different exit directions, the focusing optical element 3 will converge the incoming laser beam to different points on its focal plane. Based on the definitions of the X, Y, and Z axes, the propagation direction unit vector can be obtained. ;

[0134] The coordinates of the X, Y, and Z axes on the focal plane are:

[0135] ;

[0136] ;

[0137] ;

[0138] When the position vector at the focal plane of the laser beam is changed At different times, the degree of refraction of the laser beam varies, thus changing the incident angle of the laser beam when it reaches the workpiece. Based on the definitions of the X, Y, and Z axes, the position vector can be obtained. According to the definition, the entrance pupil position of the laser beam entering the focusing optical element can be obtained. for At this moment, the angle between the projection of the laser beam onto the XOZ plane and the Z-axis is... The angle between the projection of the object onto the YOZ plane and the Z-axis is... The included angle of the laser beam is:

[0139] ;

[0140] in This is the nonlinear angle compensation term caused by the laser beam propagation direction vector.

[0141] The laser beam is solved inversely using the aforementioned beam space vector control model, with the following steps:

[0142] Step 1: Determine the target position and incident attitude parameters of the laser beam after focusing within the processing area. ;

[0143] Step 2, Converted into a unit vector of the propagation direction at the incident focal plane of the focusing optical element 3. Position vector and focal plane position ;

[0144] Step 3: Establish the system of linear equations as follows:

[0145] ;

[0146] Step 4: Simultaneously solve for the corresponding values ​​of the X and Y axes using numerical algorithms. Deflection angle parameters of a plane mirror and the moving distance of concave lens 11 The numerical algorithm is a nonlinear regression model, such as the Gauss-Newton method or the Levenberg-Marquardt algorithm.

[0147] like Figure 1 , Figure 6 The imaging optical path of the paraxial imaging system 4 is independent of the laser processing optical path, and is used to observe the laser processing process in real time.

[0148] The rangefinder imaging system 4 includes a CCD camera 41 and an imaging objective lens 42, and its imaging optical path is spatially independent from the laser processing optical path. The rangefinder imaging system 4 is positioned to the side of the processing area. The observation field of view of the rangefinder imaging system 4 is decoupled from the action of the beam pose adjustment system 2. Even when the laser beam undergoes high-frequency deflection and translation scanning, the rangefinder imaging system 4 can still maintain a steady observation relative to the processing area, avoiding field-of-view sway and stray light interference caused by scanning actions.

[0149] The off-axis imaging system can be arranged vertically for positioning the focal plane of the machining process, or arranged at an angle for real-time observation of the machining process.

[0150] The off-axis imaging system 4, based on a spatial geometry algorithm, is used to measure the depth and morphology of the micro-holes being processed in the processing area in real time, and outputs processing image feature parameters for subsequent closed-loop control. The negative cone hole processing effect diagram using the processing device of this embodiment is shown below. Figure 7 As shown.

[0151] The specific spatial geometry algorithm is as follows:

[0152] Let the coordinates of the micro-aperture opening at the center of the image be... The coordinates of the bottom of the micropore at the center of the imaging image are: Then the pixel offsets of the two in the imaging image plane are respectively ;

[0153] By calibrating the paraxial imaging system 4, a proportional mapping relationship between image pixel coordinates and actual spatial displacement is established, with the horizontal and vertical scale coefficients set as follows: and The corresponding actual displacement component is ;

[0154] Let the angle between the line of sight of the off-axis imaging system 4 and the normal to the surface of the workpiece 5 be . The azimuth angle of the projection of the viewing axis into plane 5 of the workpiece is The depth of the hole This can be expressed as a function of the projection of the image displacement onto the observation direction and the angle between the projection and the observation direction, i.e. .

[0155] When the machined hole is an inclined hole, let the unit vector in the direction of the hole axis be... ;

[0156] in, and These represent the inclination angle of the hole axis relative to the normal of workpiece 5 and its azimuth angle in the plane of workpiece 5, respectively. and and and The principle is the same, in Figure 6 Only marked in and , and Reference for marking and Let the image displacement vector be... The paraxial imaging projection matrix is The depth of the hole can then be further expressed as .

[0157] This enables quantitative inversion of the depth of tilted micro-holes. To improve measurement accuracy, image coordinate distortion correction can be applied, establishing a nonlinear calibration relationship between the corrected image coordinates and the actual displacement. The control system then calculates the actual machined hole depth in real time. With the preset target hole depth Deviation between , can be obtained Feedback correction is performed on the dynamic focusing system 1 and the beam pose adjustment system 2 to achieve integrated closed-loop control of processing depth and morphology.

[0158] The above description is merely a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention by those skilled in the art within the scope of the technology disclosed in the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A five-axis galvanometer laser processing method, characterized in that: This method employs five-axis galvanometer laser processing, where the five axes include the X, Y, and Z axes coordinates of the target focal point within the processing area, as well as the incident tilt angle of the laser beam within the processing area. , , Let be the angle between the projection of the laser beam onto the XOZ plane and the Z-axis. Let be the angle between the projection of the laser beam onto the YOZ plane and the Z-axis; A convex lens and a concave lens are arranged along the laser beam emission direction. The concave lens can reciprocate by moving closer to or further away from the convex lens along the optical axis of the laser beam to adjust the coordinates of the target focus on the Z-axis. When the concave lens is in its initial position, the distance between the concave lens and the convex lens is , Let be the focal length of the concave lens. The focal length of the convex lens; the laser beam divergence angle. Based on the movement of the concave lens, we can obtain: Focal plane position of focusing optical element ,in To focus the effective focal length of the optical element, This is the distance between the convex lens and the focusing optical element. The moving distance of the concave lens is used to focus the optical element to convert the laser beam into a multi-dimensional vector landing point on the processing plane; Z-axis displacement in the focal plane ,in For when The position of the focal plane; Multiple rotatable plane mirrors are arranged on the exit side of the concave lens. By coordinating the rotation of these multiple plane mirrors, the X-axis and Y-axis coordinates and the incident tilt angle of the laser beam are determined. , By adjusting the parameters, we can obtain: laser beam through the first The propagation direction unit vector after the plane mirror is deflected ,in, For the first A spatial rotation matrix determined by the deflection angle of a plane mirror. For the first The propagation direction unit vector after the second reflection; The unit vector of the propagation direction of the laser beam after being deflected by multiple plane mirrors ,in, For the first The deflection angle parameters of a plane mirror The initial propagation direction is the unit vector; After propagation through multiple plane mirrors, the position vector of the laser beam at the focal plane of the focusing optics is: ,in, Let be the initial position vector of the incident laser beam. The number of plane mirrors. The first parameter is set based on the distance between adjacent plane mirrors or the distance between the mirror and the focusing optical element. The propagation length of the optical path; The processing method includes the following steps: S1. Target Trajectory Analysis and Reverse Solving: Based on the preset complex surface machining trajectory, determine the three-dimensional coordinate vector of the target focus within the machining area and the incident attitude parameters. And based on the beam space vector control model, Converted into a unit vector of the propagation direction at the incident focal plane of the focusing optical element. Position vector and focal plane position ; The system of linear equations is established as follows: The distance the concave lens moved was calculated using a numerical algorithm in reverse engineering. and the deflection angle parameters of each plane mirror. ; S2, Focal plane preset adjustment: Control the concave lens to move first, according to the calculated moving distance. The divergence angle of the laser beam is modulated to match the target focal depth, thereby achieving pre-positioning in the Z-axis dimension; S3. Spatial Vector Coordinated Deflection: Based on the concave lens control, the multiple planar mirrors are controlled in tandem, according to the solved deflection angle parameters. Generate the corresponding X-axis, Y-axis coordinates and incident tilt angle. , The laser beam is focused onto the processing area by a focusing optical element and in a specific orientation.

2. The five-axis galvanometer laser processing method according to claim 1, characterized in that: Four rotatable plane mirrors are arranged on the exit side of the concave lens, wherein the first and third plane mirrors rotate together to change the parallel displacement of the laser beam relative to the X-axis direction of the laser beam exit optical axis. The equivalent spatial rotation matrix is: The second and fourth plane mirrors rotate in tandem, altering the parallel displacement of the laser beam relative to its output optical axis along the Y-axis. The equivalent spatial rotation matrix is: We can obtain: ； ； The unit vector of the propagation direction of the laser beam after being deflected by four plane mirrors ,in, , , and These represent the deflection angles of the first, second, third, and fourth plane mirrors, respectively. , Substitute into the formula , , Substitute into the formula ; Based on the recursive relationship of the laser beam's direction at each reflector and its positional relationship in adjacent propagation segments, a system derived from the reflector deflection angle parameters can be established. Corresponding optical path propagation length Position vector to the focal plane of the focusing optical element and propagation direction unit vector Unified forward mapping function ,Right now: , It is the distance between the first and second reflecting mirrors. It is the distance between the second and third reflecting mirrors. It is the distance between the third and fourth reflecting mirrors. It is the distance between the fourth reflecting mirror and the focusing optical element.

3. The five-axis galvanometer laser processing method according to claim 1, characterized in that: In step S1 of the processing method, the laser beam, which has been controlled by the concave lens and the plane mirror, is focused onto the processing area by the focusing optical element. After focusing, the three-dimensional coordinate vector of the focal point and the incident attitude parameters of the laser beam within the processing area are determined. ,in, The coordinates of the laser beam on the focal plane of the focusing optics are the X, Y, and Z axes. Let be the angle between the projection of the laser beam onto the XOZ plane and the Z-axis. Let be the angle between the projection of the laser beam onto the YOZ plane and the Z-axis; In the beam space vector control model, when a laser beam enters the focusing optical element with different exit directions, the focusing optical element will converge the incoming laser beam to different points on its focal plane. Based on the definitions of the X, Y, and Z axes, the propagation direction unit vector can be obtained. ; The coordinates of the X, Y, and Z axes on the focal plane are: ； ； ； When the position vector at the focal plane of the laser beam is changed At different times, the degree of refraction of the laser beam varies, thus changing the incident angle of the laser beam when it reaches the workpiece. Based on the definitions of the X, Y, and Z axes, the position vector can be obtained. According to the definition, the entrance pupil position of the laser beam entering the focusing optical element can be obtained. for The included angle of the laser beam is: ； in This is the nonlinear angle compensation term caused by the laser beam propagation direction vector.

4. The five-axis galvanometer laser processing method according to claim 1, characterized in that: The processing method also includes step S4, morphology monitoring and adaptive closed loop: the feature parameters of the processed image are extracted in real time through the paraxial imaging system, the actual processing depth and morphology error are inverted, and they are used as compensation constraints to dynamically close the loop to correct the focal position and incident tilt angle. The specific process is as follows: Based on the mapping relationship between image pixel coordinates and actual spatial displacement obtained by the paraxial imaging system, the current actual processing depth is quantitatively inverted. ; Calculate the actual machining depth measured in real time With the preset target hole depth Deviation between ; Deviation Feedback is sent to the beam space vector control model to trigger the deflection angle parameters of each planar mirror. and the distance the concave lens moves The quadratic nonlinear regression solution is used to adaptively compensate for the errors of the concave lens and the plurality of plane mirrors.

5. The five-axis galvanometer laser processing method according to claim 4, characterized in that: The imaging optical path of the off-axis imaging system is independent of the laser processing optical path, and is used for real-time observation of the laser processing process; The rangefinder imaging system includes a CCD camera and an imaging objective lens. The observation field of the rangefinder imaging system is decoupled from the action of the beam pose adjustment system to maintain a steady-state observation relative to the processing area. The off-axis imaging system is used to measure the depth and morphology of the processed micro-holes in the processing area in real time; let the coordinates of the micro-hole opening at the center of the imaging image be... The coordinates of the bottom of the micropore at the center of the imaging image are: Then the pixel offsets of the two in the imaging image plane are respectively ; By calibrating the paraxial imaging system, a proportional mapping relationship between image pixel coordinates and actual spatial displacement is established, with the horizontal and vertical scale coefficients set as follows: and The corresponding actual displacement component is ; Let the angle between the line of sight of the off-axis imaging system and the normal to the workpiece surface be . The azimuth angle of the projection of the viewing axis into the workpiece plane is The depth of the hole This can be expressed as a function of the projection of the image displacement onto the observation direction and the angle between the projection and the observation direction, i.e. .

6. The five-axis galvanometer laser processing method according to claim 5, characterized in that: When the machined hole is an inclined hole, let the unit vector in the direction of the hole axis be... ; in, and Let represent the inclination angle of the hole axis relative to the workpiece normal and its azimuth angle in the workpiece plane, respectively; let the image displacement vector be . The paraxial imaging projection matrix is The hole depth is then expressed as .

7. A galvanometer laser processing apparatus, characterized in that: For implementing the five-axis galvanometer laser processing method according to any one of claims 1-6, the galvanometer laser processing device is provided with a dynamic focusing system, a beam pose adjustment system, a focusing optical element and a paraxial imaging system in sequence along the laser propagation direction; The dynamic focusing system is used to modulate the divergence angle of the laser beam. The dynamic focusing system includes a concave lens and a convex lens. The concave lens can reciprocate by moving closer to or further away from the convex lens along the optical axis of the laser beam. The beam pose adjustment system includes multiple rotatable plane mirrors. By coordinating the rotation of the multiple plane mirrors, the spatial position and incident tilt angle of the laser beam can be controlled. The focusing optical element is used to convert the laser beam into a multi-dimensional vector landing point on the processing plane; the imaging optical path of the paraxial imaging system is independent of the laser processing optical path and is used to observe the laser processing process in real time.

8. The five-axis galvanometer laser processing apparatus according to claim 7, characterized in that: The dynamic focusing system also includes a high-frequency vibration device and a fixing element; the high-frequency vibration device includes a voice coil motor, which drives the concave lens to reciprocate along the optical axis of the laser emission; the fixing element is used to fix the convex lens; the concave lens and the convex lens are arranged sequentially along the optical axis of the laser emission.

9. A five-axis galvanometer laser processing apparatus according to claim 7, characterized in that: The focusing optical element is a telecentric focusing optical system used to convert the incoming laser beam into a multi-dimensional vector landing point on the processing plane; the propagation direction of the laser beam is a unit vector. Used to determine the spatial coordinates of the laser focus on the focal plane; the position vector of the laser beam at the incident focal plane of the focusing optical element. Used to adjust the converging attitude of a laser beam after it has been refracted by a focusing optical element; The rangefinder imaging system includes a CCD camera and an imaging objective lens. The observation field of view of the rangefinder imaging system is decoupled from the action of the beam pose adjustment system to maintain steady-state observation relative to the processing area. The rangefinder imaging system can be arranged vertically for positioning the processing focal plane, or arranged at an angle for real-time observation of the processing process.

10. A five-axis galvanometer laser processing apparatus according to claim 8, characterized in that: The beam pose adjustment system includes four rotatable plane mirrors and a drive unit that drives the rotation of each plane mirror. The drive unit includes a servo motor or a galvanometer motor. The four plane mirrors include a first plane mirror, a second plane mirror, a third plane mirror, and a fourth plane mirror; The first planar reflector is positioned behind the convex lens along the optical axis of the laser beam and is used to reflect the laser beam emitted from the convex lens. The second plane mirror is disposed on the reflection path of the first plane mirror, the third plane mirror is disposed on the reflection path of the second plane mirror, and the fourth plane mirror is disposed on the reflection path of the third plane mirror; The first and third plane mirrors rotate together to control the amount of parallel displacement of the laser beam relative to the X-axis direction of the laser beam emission axis; the second and fourth plane mirrors rotate together to control the amount of parallel displacement of the laser beam relative to the Y-axis direction of the laser beam emission axis. The third and fourth plane mirrors rotate in coordination to adjust the incident angle of the laser beam into the focusing optical element.

Images