Rotating mirror scanning light path system for generating point ring light and control method thereof

Abstract

The invention discloses a rotating mirror scanning light path system for generating point ring light and a control method thereof. The light path system comprises a light source module used for outputting laser; the shaping and focusing module comprises a rotary reflecting mirror and an arc-shaped reflecting mirror which are sequentially positioned on a laser light path; the rotating reflector comprises a central area and an outer ring area, the outer ring area surrounds the central area, and the curvature radiuses of the central area and the outer ring area are different; the rotary reflecting mirror is used for reflecting the laser and shaping the laser into a point annular light spot; the arc-shaped reflector is used for focusing the annular spot; the control module is used for controlling the rotating reflector to rotate around the rotating shaft, and laser scanning in the first direction is achieved. And the control module is also used for controlling the rotary reflector and the arc reflector to integrally move and rotate to realize line scanning and rotary scanning of the laser in the second direction. According to the laser shaping device, only two arc-shaped optical reflectors and one optical fiber output laser are needed, laser can be shaped into point annular light spots, splashing can be reduced, the porosity can be reduced, and the machining quality can be improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of 3D printing optical path systems, and in particular, to a rotating mirror scanning optical path system for generating point-ring light and a control method thereof. Background Art

[0002] Currently, the external optical path system used in traditional metal 3D printers consists of a galvanometer mirror, a field lens, and a beam expander. A single-mode rotating mirror scanning optical path system is used to achieve a spot size that meets the printing requirements. However, there are many problems with existing metal 3D printers. For example:

[0003] 1. The focused spot is a Gaussian beam, which is prone to splashing and has a high porosity, affecting the processing quality.

[0004] 2. The optical path needs to pass through a field lens, and the field lens itself will introduce certain field curvature and distortion.

[0005] 3. The volume of the rotating mirror scanning optical path system is relatively large.

[0006] 4. The cost of the traditional optical path system is relatively high, consisting of a single-mode rotating mirror scanning optical path system, a galvanometer mirror, a beam expander, and a field lens. Each component is expensive.

[0007] Based on this, there is an urgent need to provide an optical path system that can solve at least one of the above problems. Summary of the Invention

[0008] The present application provides a rotating mirror scanning optical path system for generating point-ring light and a control method thereof. It only requires two arc-shaped optical reflectors and a fiber-output laser, which can shape the laser into a point-ring-shaped spot, reduce splashing and porosity, and improve the processing quality.

[0009] In a first aspect, the present application proposes a rotating mirror scanning optical path system for generating point-ring light, including:

[0010] A light source module for outputting laser;

[0011] A shaping and focusing module including a rotating reflector and an arc-shaped reflector, the rotating reflector and the arc-shaped reflector are sequentially located on the laser optical path; the rotating reflector includes a central region and an outer ring region, the outer ring region surrounds the central region, and the radius of curvature of the central region and the outer ring region is different; the rotating reflector is used to reflect the laser and shape it into a point-ring-shaped spot; the arc-shaped reflector is used to focus the point-ring-shaped spot;

[0012] The control module is used to control the rotary mirror to rotate around the rotation axis to achieve line scanning of the laser along the first direction; it is also used to control the overall movement and rotation of the rotary mirror and the arc mirror to achieve line scanning and rotational scanning of the laser along the second direction; wherein the first direction and the second direction are perpendicular.

[0013] As a preferred solution, the focal length of the rotary mirror in the meridian plane is the same as the focal length in the sagittal plane.

[0014] As a preferred solution, the focal lengths of the rotary mirror in the meridian plane and in the sagittal plane satisfy the relationship:

[0015] Frot_x = Frot_y = F1;

[0016] Frot_x = (Rrot_x * cosθ) / 2; Frot_y = Rrot_y / (2cosθ);

[0017] Wherein, θ is the half divergence angle of the laser; Frot_x is the focal length of the rotary mirror in the meridian plane, Frot_y is the focal length of the rotary mirror in the sagittal plane, Rrot_x is the radius of curvature of the rotary mirror in the meridian direction, Rrot_y is the radius of curvature of the rotary mirror in the sagittal direction; F1 is the total focal length of the rotary mirror.

[0018] As a preferred solution, the focal length of the arc mirror in the sagittal plane satisfies the relationship: Fsurf_y = Rsurf_y;

[0019] Wherein, Fsurf_y is the focal length of the arc mirror in the sagittal plane; Rsurf_y is the radius of curvature of the arc mirror in the sagittal direction.

[0020] As a preferred solution, the optical path propagation of the arc mirror in the meridian direction satisfies the condition:

[0021] Fsurf_x = Fsurf_y = F2;

[0022] Fsurf_x (meridian) = (Rsurf_x * cosθ) / 2;

[0023] Wherein, θ is the half divergence angle of the laser; Fsurf_x is the focal length of the arc mirror in the meridian plane, Rsurf_x is the radius of curvature of the arc mirror in the meridian direction; Fsurf_y is the focal length of the arc mirror in the sagittal plane; F2 is the total focal length of the arc mirror.

[0024] As a preferred solution, the reflection angle of the rotary mirror and the arc mirror is α, and the value range of α is 15° to 75°.

[0025] As a preferred solution, the spot size D0 of the laser satisfies the relationship:

[0026]

[0027] D0 = 2ω;

[0028] wherein, F1 is the total focal length of the rotating mirror, F2 is the total focal length of the arc mirror, θ is the half divergence angle of the laser; M 2 is the beam quality of the laser; λ is the wavelength of the laser; ω is the radius of the laser beam; L1 is the distance from the light output port of the fiber laser to the rotating mirror; L2 is the distance from the rotating mirror to the arc mirror; L3 is the distance from the arc mirror to the working surface.

[0029] As a preferred solution, the arc mirror is strip-shaped, and the arc length of the arc mirror is greater than the line scanning range of the laser.

[0030] As a preferred solution, the rotating mirror is located at the front focal point of the arc mirror, and its reflecting surface faces the reflecting surface of the arc mirror.

[0031] Based on the same inventive concept, in a second aspect, an embodiment of the present invention further provides a control method for a rotating mirror scanning optical path system for generating a point-ring light, which is used to control the rotating mirror scanning optical path system provided in the first aspect, including:

[0032] Controlling the rotating mirror to rotate itself to reflect the laser to the arc mirror, and shaping the light spots in the central area and the outer ring area of the rotating mirror into a point-ring-shaped light spot; the arc mirror focuses the point-ring-shaped light spot to the processing surface;

[0033] Controlling the rotating mirror to rotate itself around the rotation axis to reflect the point-ring-shaped light spot to the arc mirror, so as to realize the line scanning of the laser in the first direction;

[0034] Controlling the relative positions of the rotation axis of the rotating mirror and the central axis of the arc mirror to be fixed, and moving the rotating mirror and the arc mirror as a whole in the second direction to realize the line scanning of the laser in the second direction;

[0035] Controlling the relative positions of the rotation axis of the rotating mirror and the central axis of the arc mirror to be fixed, and rotating the rotating mirror and the arc mirror as a whole to realize the control of the laser scanning angle.

[0036] In summary, for the rotating mirror scanning optical path system provided in the embodiments of the present application, only two arc-shaped optical reflectors are required. By setting different curvature radii for the central region and the outer ring region of the rotating mirror, the laser can be shaped into a dot-ring-shaped light spot, and the output laser can be focused through the combination of the two reflectors. Further, by controlling the rotation of the rotating mirror around its own rotation axis, the laser can achieve the lateral scanning function. By performing forward and backward and rotational movements on the entire optical path system, the laser can achieve forward and backward scanning and rotational scanning. Through the optical module of the rotating mirror and the arc-shaped reflector, the functions of cost reduction and processing rate improvement can be achieved. Moreover, since the entire optical path system is relatively small, the scanning optical path system can also have the advantage of miniaturization in volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 FIG. is a schematic structural diagram of a rotating mirror scanning optical path system for generating dot-ring light provided by the present invention;

[0038] Figure 2 FIG. is a schematic diagram of the reflecting surface of a rotating mirror provided by the present invention;

[0039] Figure 3 FIG. is a schematic diagram of the energy distribution of a dot-ring-shaped light spot provided by the present invention;

[0040] Figure 4 FIG. is a schematic diagram of the optical path propagation in the sagittal plane of an arc-shaped reflector provided by the present invention;

[0041] Figure 5 FIG. is a schematic diagram of the optical path propagation in the meridional plane of an arc-shaped reflector provided by the present invention;

[0042] Figure 6 FIG. is a schematic diagram of a control method for a rotating mirror scanning optical path system for generating dot-ring light provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The following further details the present application in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present application and not for limiting the present application. Additionally, it should be noted that for the sake of description, only parts related to the present application rather than all structures are shown in the drawings. Without departing from the spirit or scope of the present application, various modifications and changes can be made to the present application, which is obvious to those skilled in the art. Therefore, the present application is intended to cover the modifications and changes of the present application that fall within the scope of the corresponding claims (the claimed technical solutions) and their equivalents. It should be noted that the embodiments provided in the embodiments of the present application can be combined with each other without conflict.

[0044] Figure 1Schematic structural diagram of a rotating mirror scanning optical path system for generating a dot-ring light provided by the present invention Figure 2 Schematic diagram of the reflecting surface of a rotating reflecting mirror provided by the present invention Figure 3 Schematic diagram of the energy distribution of a dot-ring-shaped light spot provided by the present invention. Refer to Figure 1 , the rotating mirror scanning optical path system provided by the embodiments of the present application includes a light source module 10 for outputting laser light. The shaping and focusing module 20 includes a rotating reflecting mirror 21 and a curved reflecting mirror 22, and the rotating reflecting mirror 21 and the curved reflecting mirror 22 are successively located on the laser optical path; the rotating reflecting mirror 21 includes a central region 21a and an outer ring region 21b, the outer ring region 21b surrounds the central region 21a, and the curvature radii of the central region 21a and the outer ring region 21b are different; the rotating reflecting mirror 21 is used for reflecting the laser light and shaping it into a dot-ring-shaped light spot; the curved reflecting mirror 22 is used for focusing the dot-ring-shaped light spot. The control module ( Figure 1 not shown in the figure) is used to control the rotating reflecting mirror 21 to rotate itself around the rotation axis to realize the linear scanning of the laser light on the curved reflecting mirror 22 along the first direction; it is also used to control the overall movement and rotation of the rotating reflecting mirror 21 and the curved reflecting mirror 22 to realize the linear scanning and rotational scanning of the laser light along the second direction. Among them, the first direction and the second direction are perpendicular.

[0045] Exemplarily, in a 3D space coordinate system, in the same horizontal plane, the first direction can be the transverse direction (left-right direction) X, the second direction can be the longitudinal direction (front-back direction) Y, and the rotational scanning is the Z axis. In the application of 3D printing technology, the wavelength selection of the laser light output by the light source module 10 mainly depends on the printing technology and material characteristics. The light source module 10 can use a conventional single-mode laser or a multi-mode laser. At present, the multi-mode laser has a low cost and a non-Gaussian beam light spot, and the distribution is more uniform. Specifically:

[0046] In some embodiments, in the application of selective laser sintering / fusion, the printing materials include but are not limited to metal powders (such as titanium, aluminum, steel) or polymers such as nylon (PA). The light source module 10 can select a 1064 nm (near-infrared) laser. Metals and most polymers have a high absorption efficiency for near-infrared light. 1064 nm is the standard wavelength of a fiber laser, which can balance power and focusing performance.

[0047] In some embodiments, in the application of stereolithography, the printing materials include but are not limited to metal powders or wires. The light source module 10 can select 1064 nm (near-infrared), 10.6 μm (CO2 laser) lasers. High-power lasers can achieve rapid melting. In particular, CO2 lasers are suitable for highly reflective metals (such as copper and gold). Among them, the 1064 nm (near-infrared), 10.6 μm (CO2 laser) lasers use fiber output.

[0048] In some embodiments, in selective laser thermal processing applications, the printing material includes, but is not limited to, thermoplastic powders or films. The light source module 10 can select a 1064 nm (near-infrared) laser. CO2 laser is efficiently absorbed by non-metallic materials (such as polymers, ceramics) and is suitable for low-temperature sintering.

[0049] In this application, a shaping and focusing module 20 is provided on the light output path of the laser. It only includes two arc-shaped optical reflectors, one is a rotating mirror 21 and the other is an arc mirror 22. Refer to Figure 2 , by dividing the rotating mirror 21 into a central region 21a and an outer ring region 21b, and setting different curvature radii for the central region 21a and the outer ring region 21b. When the laser reaches the central region 21a and the outer ring region 21b of the rotating mirror 21, the mirror surfaces with different curvature radii shape the spot morphology into a dot-ring-shaped spot (as Figure 3 shown). Further, the arc mirror 22 is arranged on the light path of the dot-ring-shaped spot and focuses the shaped dot-ring-shaped spot onto the focal plane M.

[0050] Among them, the dot-ring-shaped spot is that the energy distribution of the spot is centered on a central circle, and multiple ring-shaped spots surround this central circle.

[0051] Among them, this application also includes a drive motor. In 3D printing, the drive motor can be responsible for controlling the precise movement of the mechanical system (such as the print head, platform, wire feeding mechanism, etc.) to achieve the X / Y / Z axis movement of the optical path system. Such as using stepper motors, servo motors, DC motors, and linear motors, etc. Their performance directly affects printing accuracy, speed, and reliability.

[0052] Continue to refer to Figure 1 , the control module ( Figure 1(not shown in the figure) are respectively connected to the light source module 10 and the driving motor. The on / off state, laser power (dynamically adjustable from 0 to 100%), and pulse output time of the light source module 10 can be controlled in real time, so as to ensure accurate energy output. During the printing process, the rotating mirror 21 can be controlled by a high-precision driving motor to perform bidirectional self-rotation around the rotation axis (supporting continuous clockwise / counterclockwise rotation from 0 to 360°). During the rotation process, the shaped laser is reflected to the arc mirror 22 and forms a scanning line on the focal plane M through surface focusing, realizing linear scanning in the first direction (X-axis). During the printing process, the control module can also synchronously control the coordinated movement of the rotating mirror 21 and the arc mirror 22. By synchronously controlling the lateral movement of the rotating mirror 21 and the arc mirror 22 assembly, linear scanning of the laser in the second direction (Y-axis) is realized. By synchronously controlling the deflection of the rotating mirror 21 and the arc mirror 22 assembly around the vertical axis, rotational scanning of the laser along the Z-axis is realized. Further combined with the X / Y / Z three-axis movement, a three-dimensional spiral scanning or raster scanning path is constructed, with a positioning accuracy reaching the micron level, and finally realizing precise 3D processing of the processed material.

[0053] Wherein, the optical path system of the present invention may further include a high-precision moving platform, which can realize carrying the processed material, matching the optical components and the print head on the platform, and realizing precise control of 3D.

[0054] In summary, for the rotating mirror scanning optical path system provided by the embodiments of the present application, only two arc-shaped optical reflectors are required. By setting different curvature radii for the central area and the outer ring area of the rotating mirror, the laser can be shaped into a point-ring-shaped light spot, achieving the purpose of shaping and focusing the output laser through the combination of the two reflectors. Further, by controlling the rotation of the rotating mirror around its own rotation axis, the lateral scanning function of the laser can be realized. The entire optical path system of the rotating mirror and the arc mirror can also be moved forward and backward and rotated, realizing forward and backward scanning and rotational scanning of the laser. This optical path structure can achieve the functions of reducing costs and increasing the processing speed, and due to the relatively small size of the entire optical path system, the scanning optical path system can also have the advantage of miniaturization.

[0055] Figure 4 It is a schematic diagram of the sagittal plane optical path propagation of an arc mirror provided by the present invention. Figure 5 It is a schematic diagram of the meridional plane optical path propagation of an arc mirror provided by the present invention. On the basis of the above embodiments, referring to Figure 4 and Figure 5 , the arc mirror 22 is strip-shaped, and the arc surface length of the arc mirror 22 is greater than the linear scanning range of the laser in the first direction X. Such a setting can ensure that the arc mirror 22 converges the shaped laser to the focal plane M.

[0056] On the basis of the above embodiments, continue to refer to Figure 1, the rotating mirror 21 is located at the front focal point of the arc mirror 22, and its reflecting surface faces the reflecting surface of the arc mirror 22. With such a setting, it can be ensured that the outgoing light of the rotating mirror 21 always irradiates the incident arc mirror 22, avoiding aberration. Among them, the rotation axis R1 of the rotating mirror 21 is fixedly connected to the axis system of the central axis (R2) of the arc mirror 22, and the two relative positions need to be strictly maintained, which can prevent the light beam from shifting. At the same time, it is ensured that the position of the laser focus on the processing plane is consistent with the theoretical trajectory, achieving optical path calibration.

[0057] Based on the above embodiments, the light source module 10 can adopt a semiconductor laser with multimode fiber output, and the beam quality M of the laser output by the laser 2 is calculated to satisfy the following formula;

[0058] M 2 =(ωθ) / (ω0θ0); (1.1)

[0059] ω0θ0 = 2λ / π; (1.2)

[0060] θ = 2*arcsin(NA); (1.3)

[0061] Among them, ω0 is the ideal beam waist radius (at the 1 / e 2 intensity), ω is the measured beam waist radius (at the 1 / e 2 intensity); θ0 is the far-field divergence angle of the ideal beam (half angle, in radians); θ is the far-field divergence angle of the beam (half angle, in radians); λ is the laser wavelength; NA is the numerical aperture of the optical fiber (Numerical Aperture, NA). Based on the above embodiments, the present application sets the spot size D0 of the output laser to satisfy the relationship:

[0062]

[0063] D0 = 2ω; (1.8)

[0064] Among them, F1 is the total focal length of the rotating mirror 21, F2 is the total focal length of the arc mirror 22, θ is the half divergence angle of the laser; M2 is the beam quality of the laser; λ is the wavelength of the laser; ω is the radius of the laser beam; L1 is the distance from the fiber laser to the rotating mirror; L2 is the distance from the rotating mirror to the arc mirror; L3 is the distance from the arc mirror to the working surface.

[0065] It should be noted that A, B, C, and D are quantities in the calculation process, which refers to taking the imaginary number of .

[0066] Combined with the above formulas (1.1) to (1.8), the present application calculates the spot size D0 required for precise processing to meet the processing requirements of different materials.

[0067] Further, calculate the radius of curvature of the rotating mirror 21.

[0068] Among them, in an optical system (especially an asymmetric or off-axis system), the tangential plane and the sagittal plane are two key orthogonal profiles for analyzing aberrations (especially astigmatism). The tangential plane (Tangential Plane / Meridional Plane) is the plane containing the optical axis and the chief ray (the actual ray passing through the center of the aperture). The sagittal plane (Sagittal Plane) is perpendicular to the tangential plane and contains the chief ray.

[0069] Specifically, the focal lengths of the rotating mirror 21 in the tangential direction and the sagittal plane satisfy the relationship:

[0070] Frot_x = Frot_y = F1; (1.9)

[0071] Frot_x = (Rrot_x * cosθ) / 2; (1.10)

[0072] Frot_y = Rrot_y / (2cosθ); (1.11)

[0073] Among them, θ is the half divergence angle of the laser; Frot_x is the focal length of the rotating mirror 21 in the tangential plane, Frot_y is the focal length of the rotating mirror 21 in the sagittal plane, Rrot_x is the radius of curvature of the rotating mirror 21 in the tangential direction, Rrot_y is the radius of curvature of the rotating mirror 21 in the sagittal direction; F1 is the total focal length of the rotating mirror 21.

[0074] To ensure that the focal lengths of the rotating mirror 21 in the tangential plane and the sagittal plane are the same, the present application sets the radii of curvature R of the rotating mirror 21 in the tangential direction and the sagittal direction to be different. By setting according to the above formulas (1.9) to (1.11), the curvatures of the tangential plane and the sagittal plane of the rotating mirror 21 can be made different. In this way, the final focal position of the laser can be made the same.

[0075] Among them, the reflection angle α of the incident laser by the rotating mirror 21 is set, and the value range of α is 15° to 75°. Preferably, α = 45°.

[0076] The present application can shape the laser into a point-ring-shaped spot by controlling the different radii of curvature of the central region and the outer ring region of the rotating mirror 21. It should be noted that the shaping effect of the rotating mirror 21 in different regions can be seen Figure 3, the central region 21a of the mirror surface can achieve the focusing of Gaussian beams, and the outer ring region 21a generates outer ring light by controlling the radius of curvature different from that of the central region. Finally, a point-ring-shaped light spot is formed, such as Figure 4 .

[0077] Among them, the total focal length F1 of the rotating mirror 21 and the total focal length F2 of the arc mirror 22 depend on the size of the final required point-ring-shaped light spot, and can be calculated by the light spot size calculation formulas (1.4)-(1.8). The radius of curvature corresponding to the total focal length F2 of the arc mirror 22 can be further calculated by the radius of curvature formula (1.9)~(1.11) of the rotating mirror 21.

[0078] Exemplarily, the total focal length F1 of the rotating mirror 21 is selected as 150 mm, and the total focal length F2 of the arc mirror 22 is 250 mm. Since the rotating mirror 21 needs to be placed at the focal position of the strip-shaped arc mirror, the rotating mirror 21 needs to be placed at the position of the front focal point (250 mm) of the arc mirror 22. For the two mirrors, the reflection angle θ is taken as 45°, and the specific radius of curvature is calculated as follows:

[0079] Step S1: The focal length of the rotating mirror 21 in the meridional plane is Frot_x = 150 mm = (Rrot_x * cosθ) / 2, and the calculated Rrot_x of the rotating mirror 21 is 424.26 mm. The focal length of the rotating mirror 21 in the sagittal plane is Frot_y = 150 mm = Rrot_y / (2cosθ), and the calculated Rrot_y of the rotating mirror 21 is 212.132 mm.

[0080] Step S2: The focal length of the arc mirror 22 in the sagittal plane is Fsurf = Rsurf_y, then Rsurf_y = 250 mm; its focal length in the meridional plane is Fsurf = (Rsurf_x * cosθ) / 2, then Rsurf_x = 707 mm.

[0081] Furthermore, calculate the position and radius of curvature of the long strip-shaped arc mirror 22.

[0082] It should be noted that the optical path propagation of the sagittal plane of the arc mirror 22 needs to meet two conditions:

[0083] 1). Refer to Figure 4 , assuming that the position of point O is the position of the rotating mirror 21, the light reflected by its rotation needs to be vertically input into the plane where O' is located, as shown by the solid line in Figure 4 . That is to say, the divergent light reflected by point O becomes parallel light after passing through the arc mirror 22. This also indicates that the rotating mirror 21 needs to be placed at the front focal point of the arc mirror 22, that is, the position of point O.

[0084] 2). Continue to refer to Figure 4 Considering that the spot morphology finally focused at the O' point should be as round as possible, the focal length Fsurf_y (sagittal) of the arc mirror 22 in the sagittal plane is set to be the same as its radius of curvature Rsurf_y. In this way, the spot sizes at the focal points of the meridional plane and the sagittal plane of the arc mirror 22 can be the same, obtaining a circular spot, which is beneficial to improving the processing accuracy after focusing.

[0085] That is, the focal length of the arc mirror 22 in the sagittal plane satisfies the relationship:

[0086] Fsurf_y (sagittal) = Rsurf_y; (1.12)

[0087] Where, Fsurf_y is the focal length of the arc mirror 22 in the sagittal plane; Rsurf_y is the radius of curvature of the arc mirror 22 in the sagittal direction.

[0088] Continue to refer to Figure 4 Considering that the spot morphology finally focused at the O' point should be as round as possible, the focal length Fsurf_y (sagittal) of the arc mirror 22 in the sagittal plane is set to be the same as its radius of curvature Rsurf_y. In this way, the spot sizes at the focal points of the meridional plane and the sagittal plane of the arc mirror 22 can be the same, obtaining a circular spot, which is beneficial to improving the processing accuracy after focusing.

[0089] Furthermore, referring to Figure 5 In this application, the optical path propagation of the arc mirror 22 in the meridional direction satisfies the condition:

[0090] Fsurf_x = Fsurf_y = F2; (1.13)

[0091] Fsurf_x (meridional) = (Rsurf_x * cosθ) / 2; (1.14)

[0092] Where, θ is the divergence half-angle of the laser; Fsurf_x is the focal length of the arc mirror 22 in the meridional plane, Rsurf_x is the radius of curvature of the arc mirror 22 in the meridional direction, and F2 is the total focal length of the arc mirror 22.

[0093] Combining formulas (1.12) to (1.14), by calculating and setting Rsurf_x and Rsurf_y, the focal length Fsurf_x of the arc mirror 22 in the meridional plane and the focal length Fsurf_y of the arc mirror 22 in the sagittal plane can be made the same, so that the shaped point-ring spot can be focused on the same focal plane, thereby improving the 3D processing accuracy.

[0094] Among them, the reflection angle α of the arc mirror 22 for the incident light is set, and the value range of α is 15° to 75°, preferably α = 45°.

[0095] Based on the same inventive concept, an embodiment of the present invention also provides a control method for a rotating mirror scanning optical path system that generates a dot-ring light, which is used to control the rotating mirror scanning optical path system provided in the above embodiment. Figure 6 It is a schematic diagram of a control method for a rotating mirror scanning optical path system that generates a dot-ring light provided by the present invention. Refer to Figures 1 - 6 , the control method includes:

[0096] S101. Control the rotating reflecting mirror to rotate itself to reflect the laser to the arc mirror. The central area and the outer ring area of the rotating reflecting mirror shape the light spot into a dot-ring light spot; the arc mirror focuses the dot-ring light spot onto the processing surface.

[0097] Specifically, refer to Figure 1 , during the printing process, the rotating reflecting mirror 21 shapes the laser output by the semiconductor laser 10 into a dot-ring light spot, and the arc mirror 22 focuses the dot-ring light spot onto the focal plane M (processing surface).

[0098] S102. Control the rotating reflecting mirror to rotate itself around the rotation axis to reflect the dot-ring light spot to the arc mirror, so as to realize the linear scanning of the laser along the first direction.

[0099] Specifically, the control module controls the rotating reflecting mirror 21 to rotate itself around the rotation axis through the driving motor to reflect the shaped laser to the arc mirror 22, and the arc mirror 22 focuses the shaped laser onto the focal plane M, so as to realize the linear scanning of the laser along the first direction X.

[0100] S103. Control the relative positions of the rotation axis of the rotating reflecting mirror and the central axis of the arc mirror to be fixed, and move the rotating reflecting mirror and the arc mirror as a whole along the second direction to realize the linear scanning of the laser along the second direction.

[0101] Specifically, the control module can also control the overall movement of the rotating reflecting mirror 21 and the arc mirror 22 through the driving motor, so that the focused laser scans along the second direction Y to realize the 3D processing of the processing material.

[0102] S104. Control the relative positions of the rotation axis of the rotating reflecting mirror and the central axis of the arc mirror to be fixed, and rotate the rotating reflecting mirror and the arc mirror as a whole to realize the control of the laser scanning angle.

[0103] Specifically, the control module can also control the overall rotation of the rotating reflecting mirror 21 and the arc mirror 22 through the driving motor, so that the focused laser rotates and scans along the Z axis to realize the 3D processing of the processing material.

[0104] It should be noted that steps S102, S103, and S104 can be carried out simultaneously or non-simultaneously according to processing requirements to complete complex processing techniques, and the steps of this application are not limited to the process sequence.

[0105] In summary, for the rotating mirror scanning optical path system for generating a point-ring light provided in the embodiment of the present application, only two arc-shaped optical reflectors and one laser light source are required, and the overall optical path is simple and the cost is low. The optical path does not need to pass through a field lens, and there is no additionally introduced field curvature and distortion. At the same time, a multimode semiconductor laser can be used, which has a small size, low cost, and a relatively uniform spot distribution. During the processing, the control method of the rotating mirror scanning optical path system generating a point-ring-shaped spot is simple and easy to operate. The focused spot is a point-ring-shaped spot, which can reduce spatter and has a low porosity, and is beneficial to improving the processing yield.

[0106] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. The features of the various embodiments of the present invention can be partially or fully coupled or combined with each other, and can cooperate with each other in various ways and be technically driven. Various obvious changes, re-adjustments, combinations with each other, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A rotating mirror scanning optical path system for generating point ring light, characterized in that: include: A light source module, used for outputting laser; A shaping and focusing module comprises a rotating reflector and an arc reflector, wherein the rotating reflector and the arc reflector are sequentially arranged on a laser light path; the rotating reflector comprises a central region and an outer ring region, wherein the outer ring region surrounds the central region, and the central region and the outer ring region have different curvature radii; the rotating reflector is used to reflect the laser and shape it into a point ring-shaped light spot; and the arc reflector is used to focus the point ring-shaped light spot; The control module is used to control the rotating reflector to rotate about the rotation axis to realize line scanning of the laser along a first direction; and is also used to control the overall movement and rotation of the rotating reflector and the arc reflector to realize line scanning and rotation scanning of the laser along a second direction; wherein the first direction is perpendicular to the second direction.

2. The rotating mirror scanning optical path system according to claim 1, characterized in that: The focal length of the rotating reflector on the meridian plane is the same as the focal length on the sagittal plane.

3. The rotating mirror scanning optical path system according to claim 2, characterized in that: The focal length of the rotating reflector on the meridian plane and the focal length on the sagittal plane satisfy the relationship: Frot_x=Frot_y=F1; Frot_x=(Rrot_x*cosθ) / 2; Frot_y=Rrot_y / (2cosθ); Among them, θ is the divergence half angle of the laser; Frot_x is the focal length of the rotating reflector on the meridian plane, Frot_y is the focal length of the rotating reflector on the sagittal plane, Rrot_x is the curvature radius of the rotating reflector in the meridian direction, Rrot_y is the curvature radius of the rotating reflector in the sagittal direction; F1 is the total focal length of the rotating reflector.

4. The rotating mirror scanning optical path system according to claim 1, characterized in that: The focal length of the arc reflector on the sagittal plane satisfies the relationship: Fsurf_y = Rsurf_y; Among them, Fsurf_y is the focal length of the arc reflector on the sagittal plane; Rsurf_y is the curvature radius of the arc reflector in the sagittal direction.

5. The rotating mirror scanning optical path system according to claim 1, characterized in that: The optical path propagation of the arc reflector in the meridian direction satisfies the condition: Fsurf_x = Fsurf_y = F2; Fsurf_x(meridian)=(Rsurf_x*cosθ) / 2; Among them, θ is the divergence half angle of the laser; Fsurf_x is the focal length of the arc reflector on the meridian plane, Rsurf_x is the curvature radius of the arc reflector in the meridian direction; Fsurf_y is the focal length of the arc reflector on the sagittal plane; F2 is the total focal length of the arc reflector.

6. The rotating mirror scanning optical path system according to claim 1, characterized in that: The reflection angle of the rotating reflector and the arc reflector is α, and the value range of α is 15° to 75°.

7. The rotating mirror scanning optical path system according to claim 1, characterized in that: The laser spot size D0 satisfies the relationship: D0=2ω; Wherein, F1 is the total focal length of the rotating reflector, F2 is the total focal length of the arc reflector, and θ is the divergence half angle of the laser; M 2 is the beam quality of the laser; λ is the wavelength of the laser; ω is the radius of the laser beam; L1 is the distance from the light outlet of the fiber laser to the rotating reflector; L2 is the distance from the rotating reflector to the arc reflector; L3 is the distance from the arc reflector to the working surface.

8. The rotating mirror scanning optical path system according to claim 1, characterized in that: The arc reflector is in the shape of an elongated strip, and the arc length of the arc reflector is greater than the line scanning range of the laser in the first direction.

9. The rotating mirror scanning optical path system according to claim 1, characterized in that: The rotating reflector is located at the front focal plane of the arc reflector, and its reflecting surface faces the reflecting surface of the arc reflector; the rotating axis of the rotating reflector and the central axis of the arc reflector are fixed relative to each other.

10. A method for controlling a rotating mirror scanning optical path system for generating a spot ring light, used for controlling the rotating mirror scanning optical path system according to any one of claims 1 to 9, characterized in that: The control method comprises: The rotating reflector is controlled to rotate to reflect the laser to the arc reflector, and the central area and the outer ring area of ​​the rotating reflector are used to shape the light spot into a point ring light spot; the arc reflector focuses the point ring light spot to the processing surface; Control the rotating reflector to rotate along the rotating axis to reflect the dot ring-shaped light spot to the arc-shaped reflector, so as to realize line scanning of the laser along the first direction; The rotation axis of the rotating reflector and the central axis of the arc reflector are controlled to be fixed relative to each other, and the rotating reflector and the arc reflector are moved integrally along the second direction to realize line scanning of the laser along the second direction; The relative positions of the rotation axis of the rotating reflector and the central axis of the arc reflector are controlled to be fixed, and the rotating reflector and the arc reflector are rotated as a whole to realize the laser scanning angle control.

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