Point-loop power ratio stepless regulation device based on phase modulation

Abstract

The invention discloses a point loop power ratio stepless regulation device based on phase modulation, which belongs to the technical field of beam shaping and comprises a first diffractive optical element and a second diffractive optical element which are coaxially arranged and can be relatively rotationally regulated; one surface of the second diffractive optical element away from the first diffractive optical element is used as an incident surface, and one surface of the first diffractive optical element away from the second diffractive optical element is used as an emergent surface; the first diffractive optical element and the second diffractive optical element are based on phase modulation, emergent light of the emergent surface is focused in a point state at a first angle after passing through an application light path, is in a ring state at a second angle, and is in a point-ring coexistence state between the first angle and the second angle. Based on the principle of phase modulation, the point-loop power ratio can be adjusted through relative rotation of the first diffractive optical element and the second diffractive optical element, stepless adjustment of the power ratio of Gaussian light spots and annular light spots is achieved, and the process quality of additive manufacturing or welding is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of light beam shaping, in particular to a point-ring power ratio stepless adjustment device based on phase modulation. Background Art

[0002] In the field of additive manufacturing, beam shaping (annular spot) AM solutions offer significant advantages in producing complex structures, small-batch customized production, and high-precision parts. These solutions can be combined with traditional casting processes (focused Gaussian spot). Selective laser melting (SLM), a type of laser powder bed fusion (LPBF) AM technology, currently combines beam shaping (annular spot) with traditional casting processes. The annular spot achieves efficient printing of a wide melt pool and wide scanning spacing within the workpiece, while the Gaussian beam achieves high-quality, detailed printing of exterior contours and details, achieving a perfect combination of high efficiency and high quality. Furthermore, beam shaping (annular spot) optimizes melt pool stability, reduces defects, and reduces subsequent processing requirements, energy consumption, and costs, making it a major technological trend in the AM industry. In the future, the additive manufacturing SLM process is expected to achieve further power increases (above 2000W) to improve efficiency. At this point, pure annular spot shaping is insufficient, and a combination of dot-ring (Gaussian and annular spot) shaping is required.

[0003] In the field of laser welding, with the increasing supply of high-power near-infrared fiber lasers, limiting factors such as spatter, undercut, hump, and weld porosity become prominent at high welding speeds. Using a special spot profile consisting of a Gaussian spot and a concentric annular spot can significantly reduce these phenomena, but the optimal power ratio of the Gaussian spot to the annular spot varies depending on the welding process parameters and system settings.

[0004] The adjustable spot-ring power ratio helps to find the optimal process effect. How to achieve spot-ring energy regulation is a technical problem that needs to be solved in the fields of additive manufacturing and laser welding. Summary of the Invention

[0005] The purpose of the present invention is to provide a point-ring power ratio stepless adjustment device based on phase modulation to solve the problems existing in the above-mentioned prior art. Based on the principle of phase modulation, the relative rotation of the first diffractive optical element and the second diffractive optical element can be used to adjust the point-ring power ratio, thereby realizing stepless adjustment of the power ratio of the Gaussian spot and the annular spot, and improving the process quality of additive manufacturing or welding.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a point-ring power ratio stepless adjustment device based on phase modulation, comprising a first diffractive optical element and a second diffractive optical element, wherein the first diffractive optical element and the second diffractive optical element are coaxially arranged and can be relatively rotated and adjusted; a surface of the second diffractive optical element away from the first diffractive optical element serves as an incident surface, and a surface of the first diffractive optical element away from the second diffractive optical element serves as an exit surface; the first diffractive optical element and the second diffractive optical element are based on phase modulation, and at a first angle, the emergent light of the exit surface is focused into a point state after passing through an applied optical path, and at a second angle, it is focused into a ring state, and between the first angle and the second angle, it is a point-ring coexistence state.

[0008] In one embodiment, the second diffractive optical element has the same phase structure as the first diffractive optical element, is arranged opposite to each other, and has a phase of 0 / pi in both radial and circumferential directions and is repeated periodically.

[0009] In one embodiment, it also includes a rotating component, a first adjustment component and a second adjustment component, the second diffractive optical element is installed on the rotating component, the rotating component is rotatably connected to the first adjustment component, the first diffractive optical element is installed on the first adjustment component, the first adjustment component is used to adjust the radial position of the first diffractive optical element, the first adjustment component is connected to the moving part of the second adjustment component, and the second adjustment component is used to adjust the radial position of the second diffractive optical element.

[0010] In one embodiment, the rotating assembly includes a rotating shell and a second limiting ring, the second diffractive optical element is installed in the rotating shell, the second limiting ring is used to limit the axial position of the second diffractive optical element, and the rotating shell is rotatably connected to the fixed part of the first adjustment assembly.

[0011] In one embodiment, the rotating housing has a rotating connection portion and a rotating portion, the rotating connection portion is used to be rotationally connected to the fixing portion of the first adjusting assembly, and the rotating portion is used for a rotating operation.

[0012] In one embodiment, the first adjustment assembly includes a first shell, a first mounting ring, a first limiting ring, a first X-direction adjustment structure and a first Y-direction adjustment structure. The first diffractive optical element is mounted in the first mounting ring and axially limited by the first limiting ring. The first mounting ring is located in the first shell. The first X-direction adjustment structure is used to adjust the first mounting ring in the X direction, and the first Y-direction adjustment structure is used to adjust the first mounting ring in the Y direction.

[0013] In one embodiment, the first X-direction adjustment structure includes a first X-direction screw and a first X-direction pad, the first X-direction screw and the first X-direction pad are respectively located on both sides of the X-direction of the first mounting ring, and the first X-direction screw is threadedly connected to the first shell; the first Y-direction adjustment structure includes a first Y-direction screw and a first Y-direction pad, the first Y-direction screw and the first Y-direction pad are respectively located on both sides of the Y-direction of the first mounting ring, and the first Y-direction screw is threadedly connected to the first shell.

[0014] In one embodiment, the second adjustment assembly includes a second shell, a second mounting ring, a second X-direction adjustment structure and a second Y-direction adjustment structure, the first shell is connected to the second mounting ring, the second mounting ring is located in the second shell, the second X-direction adjustment structure is used to adjust the second mounting ring in the X direction, and the second Y-direction adjustment structure is used to adjust the second mounting ring in the Y direction.

[0015] In one embodiment, the second X-direction adjustment structure includes a second X-direction screw and a second X-direction pad, the second X-direction screw and the second X-direction pad are respectively located on both sides of the second mounting ring in the X direction, and the second X-direction screw is threadedly connected to the second shell; the second Y-direction adjustment structure includes a second Y-direction screw and a second Y-direction pad, the second Y-direction screw and the second Y-direction pad are respectively located on both sides of the second mounting ring in the Y direction, and the second Y-direction screw is threadedly connected to the second shell.

[0016] In one embodiment, an electric module is further included, which includes a first module for driving the rotating component to rotate, a second module for driving the first adjusting component to adjust radially, and a third module for driving the second adjusting component to adjust radially.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The present invention coaxially arranges a first diffractive optical element and a second diffractive optical element so that they can rotate relative to each other. Based on the principle of phase modulation, after a Gaussian light beam passes through the second diffractive optical element and the first diffractive optical element in sequence and undergoes an applied optical path, a point-ring coexistence state of the focused light beam can be obtained. By adjusting the relative angle between the first diffractive optical element and the second diffractive optical element within a certain angle range, the point-ring power ratio can be adjusted, achieving stepless adjustment of the power ratio of the Gaussian spot and the annular spot, thereby improving the process quality of additive manufacturing or welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the overall structure of the regulating device in an embodiment of the present invention;

[0021] Figure 2 This is a front view of the adjusting device in an embodiment of the present invention;

[0022] Figure 3 for Figure 2 Middle AA section view;

[0023] Figure 4 for Figure 2 Middle BB cross-section;

[0024] Figure 5 A top view of the adjusting device in an embodiment of the present invention;

[0025] Figure 6 for Figure 5 Middle CC section view;

[0026] Figure 7 for Figure 5 Middle DD section view;

[0027] Figure 8 Schematic diagram of the structural principles of the first diffractive optical element and the second diffractive optical element;

[0028] Among them, 1. second adjustment component; 2. first adjustment component; 3. rotation component; 4. first diffractive optical element; 5. second diffractive optical element;

[0029] 11. Second housing; 12. Second mounting ring; 13. Second X-axis adjustment structure; 14. Second Y-axis adjustment structure;

[0030] 131, second X-direction screw; 132, second X-direction pad; 141, second Y-direction screw; 142, second Y-direction pad;

[0031] 21. First housing; 22. First mounting ring; 23. First limiting ring; 24. First X-axis adjustment structure; 25. First Y-axis adjustment structure;

[0032] 241, first X-direction screw; 242, first X-direction pad; 251, first Y-direction screw; 252, first Y-direction pad;

[0033] 31. Rotating housing; 32. Second limiting ring;

[0034] 41. First phase-matched glass substrate; 42. First LCP liquid crystal layer; 43. First protective glass substrate;

[0035] 51. Second phased glass substrate; 52. Second LCP liquid crystal layer; 53. Second protective glass substrate. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] The purpose of the present invention is to provide a point-ring power ratio stepless adjustment device based on phase modulation to solve the problems existing in the prior art. Based on the principle of phase modulation, the point-ring power ratio can be adjusted by utilizing the relative rotation of the first diffractive optical element and the second diffractive optical element, thereby realizing stepless adjustment of the power ratio of the Gaussian spot and the annular spot, and improving the process quality of additive manufacturing or welding.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] The first diffractive optical element and the second diffractive optical element mentioned in the present invention are both diffractive optical elements, referred to as DOE (Diffractive Optical Element), which are optical elements designed based on the diffraction principle of light. They control the phase, amplitude or polarization of light waves through micro-nano structures to achieve functions that are difficult to accomplish with traditional refractive optical elements.

[0040] like Figures 1 to 8As shown, the present invention provides a phase-modulated, stepless adjustment device for a spot ring power ratio, comprising a first diffractive optical element 4 and a second diffractive optical element 5. The first diffractive optical element 4 and the second diffractive optical element 5 are coaxially arranged and relatively rotatable. The coaxial arrangement ensures adjustment accuracy, and relative rotation can change the spot ring power ratio. The side of the second diffractive optical element 5 facing away from the first diffractive optical element 4 serves as an incident surface, and the side of the first diffractive optical element 4 facing away from the second diffractive optical element 5 serves as an exit surface. A Gaussian beam passes from the incident surface, sequentially through the second diffractive optical element 5 and the first diffractive optical element 4, and then emerges from the exit surface into a subsequent application optical path. The first diffractive optical element 4 and the second diffractive optical element 5 are based on phase modulation. At a first angle (i.e., the first relative position of the first diffractive optical element 4 and the second diffractive optical element 5, the angle can be recorded as 0 degrees at this time), the emergent light from the emergent surface is focused into a point state (Gaussian spot) after passing through the applied optical path. At a second angle (i.e., the second relative position of the first diffractive optical element 4 and the second diffractive optical element 5, the angle can be recorded as a degree at this time, and the value of a varies according to the specific parameters of the first diffractive optical element 4 and the second diffractive optical element 5, for example, a=15), it is in a ring state (annular spot). Between the first angle and the second angle, it is a point-ring coexistence state. Therefore, when the relative angle of the first diffractive optical element 4 and the second diffractive optical element 5 is adjusted within the range of the first angle and the second angle, the point-ring state can be steplessly adjusted, and the point-ring size ratio can be customized according to actual application requirements.

[0041] The present invention coaxially arranges the first diffractive optical element 4 and the second diffractive optical element 5 so that the two can rotate relative to each other. Based on the principle of phase modulation, after the Gaussian light beam passes through the second diffractive optical element 5 and the first diffractive optical element 4 in sequence and passes through the applied optical path, a point ring coexistence state of the beam focus can be obtained. By adjusting the relative angle between the first diffractive optical element 4 and the second diffractive optical element 5 within a certain angle range, the point ring power ratio can be adjusted, and the power ratio of the Gaussian spot and the annular spot can be steplessly adjusted, thereby improving the process quality of additive manufacturing or welding.

[0042] In one embodiment, the second diffractive optical element 5 has the same phase structure as the first diffractive optical element 4 , is disposed opposite to each other, and has a phase of 0 / pi in both radial and circumferential directions and is periodically repeated.

[0043] The radial 0 / pi phase cycle repeats, and the size of the phase cycle determines the size of the annular spot. The larger the period, the smaller the annular spot size, and vice versa. The 0 / pi phase cycle repeats in the circumferential direction, and the size of the phase cycle determines the continuity of the annular spot energy distribution. The smaller the period, the more continuous the annular spot energy distribution and the smaller the high order. Two DOEs (diffractive optical elements, i.e., the first diffractive optical element 4 or the second diffractive optical element 5, the same below) have the same phase structure and are installed in the optical path, with the two DOEs set opposite each other. Rotating the relative angle of the two DOEs can achieve stepless adjustment of the spot ring power ratio.

[0044] DOE is made of fused silica glass substrate and liquid crystal polymer (LCP) material. During production, the glass substrate is first aligned using optical alignment technology, then coated with an LCP liquid crystal layer, and then a glass substrate is used as a protective glass to laminate it. The final form presents a sandwich structure of "front and back glass substrates, and LCP functional film layer in the middle". In addition, anti-reflection films can be set on the aligned glass substrate surface and the protective glass substrate surface respectively. Figure 8 As shown, the first diffractive optical element 4 includes a first-phased glass substrate 41, a first LCP liquid crystal layer 42 and a first protective glass substrate 43; the second diffractive optical element 5 includes a second-phased glass substrate 51, a second LCP liquid crystal layer 52 and a second protective glass substrate 53.

[0045] Based on the above structure, the two DOEs mentioned above are arranged relative to each other, which means that the incident light passes through the glass substrate matched with the second diffractive optical element 5, the protective glass substrate of the second diffractive optical element 5, the protective glass substrate of the first diffractive optical element 4, and the glass substrate matched with the first diffractive optical element 4 in sequence; that is, Figure 8 As shown, the incident light passes through the second aligned glass substrate 51 , the second LCP liquid crystal layer 52 , the second protective glass substrate 53 , the first protective glass substrate 43 , the first LCP liquid crystal layer 42 , and the first aligned glass substrate 41 in sequence.

[0046] When the two DOEs are rotated relative to each other by an angle of 0 degrees (i.e., the first angle), that is, there is no rotation, the phase structures of the two DOEs are the same but in opposite directions, and the phase modulation effect on the incident light spot is just offset, which is equivalent to the effect of a half-wave plate. The incident light spot passes directly and is focused into a diffraction-limited Gaussian spot (point state) after the application of the optical path. When the two DOEs are rotated relative to each other by an angle of 0 phase in a single cycle of a circle (i.e., the second angle), the combined phase of the two DOEs is just equivalent to the second-order conical lens phase, and is focused into a ring-shaped spot of corresponding size (ring-shaped spot state) after the application of the optical path. The principle of the modulation effect of the conical lens phase on the incident light spot can be referred to the liquid crystal Jones matrix theory. When the relative rotation angle of the two DOEs is between 0 degrees and the 0 phase of a single cycle of the circle, the point and the ring coexist. The continuous change process of the relative rotation angle of the two DOEs is the process of the 0 phase area gradually decreasing and gradually approaching the second-order conic lens phase. The light in the 0 phase area is modulated and directly becomes a Gaussian spot after the applied optical path, and the other areas are modulated into annular spots. In this way, the power ratio of the point and the ring changes continuously, realizing stepless adjustment of the point-ring power ratio.

[0047] In one embodiment, if Figures 1 to 7 As shown, the optical system further includes a rotating assembly 3, a first adjustment assembly 2, and a second adjustment assembly 1. The second diffractive optical element 5 is mounted on the rotating assembly 3. The rotating assembly 3 can drive the second diffractive optical element 5 to rotate. The rotating assembly 3 is rotatably connected to the first adjustment assembly 2. The first diffractive optical element 4 is mounted on the first adjustment assembly 2. Therefore, when the rotating assembly 3 drives the second diffractive optical element 5 to rotate, relative rotation between the second diffractive optical element 5 and the first diffractive optical element 4 can be achieved. The first adjustment assembly 2 is used to adjust the radial position of the first diffractive optical element 4 so that the first diffractive optical element 4 and the second diffractive optical element 5 are coaxial. The first adjustment assembly 2 is connected to the movable portion of the second adjustment assembly 1 (such as the second mounting ring 12 mentioned below). That is, when the second adjustment assembly 1 is adjusted, it can drive the entire first adjustment assembly 2 to move, and then drive the rotating assembly 3 and the second diffractive optical element 5 to move. As a result, the second adjustment assembly 1 can be used to adjust the radial position of the second diffractive optical element 5.

[0048] In one embodiment, if Figures 1 to 7 As shown, the rotating assembly 3 includes a rotating shell 31 and a second limiting ring 32. The second diffractive optical element 5 is installed in the rotating shell 31. The second limiting ring 32 is installed on one side of the second diffractive optical element 5. The axial position of the second diffractive optical element 5 can be limited by the second limiting ring 32. The rotating shell 31 is rotatably connected to the fixed part of the first adjustment assembly 2 (such as the first shell 21 mentioned later), and the rotating shell 31 is not adjusted by the first adjustment assembly 2.

[0049] In one embodiment, if Figures 1 to 7As shown, the rotating shell 31 has a rotating connection part and a rotating part. The rotating connection part is used to be rotatably connected to the fixed part of the first adjusting component 2. The fixed part of the first adjusting component 2 is used to form a precise rotation support for the rotating connection part. The rotating part is used for rotation operation, and a scale can be set on its circumferential surface to facilitate determination of the initial position state and the position state after rotation.

[0050] In one embodiment, if Figures 1 to 7 As shown, the first adjustment assembly 2 includes a first housing 21, a first mounting ring 22, a first limiting ring 23, a first X-axis adjustment structure 24, and a first Y-axis adjustment structure 25. The first diffractive optical element 4 is mounted within the first mounting ring 22 and axially limited by the first limiting ring 23. The first mounting ring 22 is located within the first housing 21. It should be noted that to facilitate the installation of various components, the position of the first housing 21 where the first mounting ring 22 is mounted can be a separate structure from the position of the first housing 21 where the rotating housing 31 (rotating connection portion) is mounted. The separate structures are connected and fixed by screws or bolts. The first X-axis adjustment structure 24 is used to adjust the first mounting ring 22 in the X direction, and the first Y-axis adjustment structure 25 is used to adjust the first mounting ring 22 in the Y direction. Therefore, through the cooperation of the first X-axis adjustment structure 24 and the first Y-axis adjustment structure 25, the position of the first mounting ring 22 in a plane can be precisely adjusted, and thus the radial position of the first diffractive optical element 4 can be adjusted.

[0051] In one embodiment, if Figures 1 to 7 As shown, the first X-direction adjustment structure 24 includes a first X-direction screw 241 and a first X-direction pad 242. The first X-direction screw 241 and the first X-direction pad 242 are respectively located on either side of the first mounting ring 22 in the X direction. The first X-direction screw 241 is threadedly connected to the first housing 21, and the end of the first X-direction screw 241 abuts the first mounting ring 22. The end of the first X-direction screw 241 can be provided with a steel ball, and a high-strength baffle can be provided at a corresponding position on the first mounting ring 22 to ensure both precision and strength. The first X-direction pad 242 can be an L-shaped plate, which has elastic deformation and recovery properties and good support capacity.

[0052] When the first X-direction screw 241 is tightened, the first mounting ring 22 can be pushed to move toward the first X-direction pad 242. The first X-direction pad 242 itself is elastic and can be compressed to provide abutment force to ensure the stability of the X-direction position of the first mounting ring 22. When the first X-direction screw 241 is loosened, the first mounting ring 22 is pushed to reset under the action of the elastic force of the first X-direction pad 242. Therefore, through the cooperation of the first X-direction screw 241 and the first X-direction pad 242, the position of the first mounting ring 22 can be accurately adjusted in the X-direction.

[0053] The first Y-axis adjustment structure 25 includes a first Y-axis screw 251 and a first Y-axis pad 252, which are located on either side of the first mounting ring 22 in the Y direction. The first Y-axis screw 251 is threadedly connected to the first housing 21, and the end of the first Y-axis screw 251 abuts the first mounting ring 22. A steel ball can be positioned at the end of the first Y-axis screw 251, and a high-strength baffle can be installed at a corresponding position on the first mounting ring 22 to ensure both precision and strength. The first Y-axis pad 252 can be an L-shaped plate, which has the elasticity to deform and recover, while also providing good support capacity.

[0054] When the first Y-direction screw 251 is tightened, the first mounting ring 22 can be pushed to move toward the first Y-direction pad 252. The first Y-direction pad 252 itself is elastic and can be compressed to provide abutment force to ensure the stability of the Y-direction position of the first mounting ring 22; when the first Y-direction screw 251 is loosened, the first mounting ring 22 is pushed to reset under the action of the elastic force of the first Y-direction pad 252. Therefore, through the cooperation of the first Y-direction screw 251 and the first Y-direction pad 252, the position of the first mounting ring 22 can be accurately adjusted in the Y-direction.

[0055] In one embodiment, if Figures 1 to 7 As shown, the second adjustment assembly 1 includes a second housing 11, a second mounting ring 12, a second X-axis adjustment structure 13, and a second Y-axis adjustment structure 14. The first housing 21 is connected to the second mounting ring 12, which is located within the second housing 11. That is, the movement of the second mounting ring 12 drives the movement of the first housing 21. The second X-axis adjustment structure 13 is used to adjust the second mounting ring 12 in the X direction, and the second Y-axis adjustment structure 14 is used to adjust the second mounting ring 12 in the Y direction. Thus, through the cooperation of the second X-axis adjustment structure 13 and the second Y-axis adjustment structure 14, the position of the second mounting ring 12 in a plane can be precisely adjusted, and thus the positions of the first housing 21 and the rotating housing 31 in a plane can be adjusted, and ultimately the radial position of the second diffractive optical element 5 can be adjusted.

[0056] In one embodiment, if Figures 1 to 7 As shown, the second X-direction adjustment structure 13 includes a second X-direction screw 131 and a second X-direction pad 132, which are located on either side of the second mounting ring 12 in the X direction. The second X-direction screw 131 is threadedly connected to the second housing 11, and the end of the second X-direction screw 131 abuts the second mounting ring 12. The end of the second X-direction screw 131 can be provided with a steel ball, and a high-strength baffle can be provided at the corresponding position on the second mounting ring 12 to ensure both precision and strength. The second X-direction pad 132 can be an L-shaped plate, which has elastic deformation and recovery properties and good support capacity.

[0057] When the second X-direction screw 131 is tightened, the second mounting ring 12 can be pushed to move toward the second X-direction pad 132. The second X-direction pad 132 itself is elastic and can be compressed to provide abutment force to ensure the stability of the X-direction position of the second mounting ring 12; when the second X-direction screw 131 is loosened, the elastic force of the second X-direction pad 132 pushes the second mounting ring 12 to reset. Therefore, through the cooperation of the second X-direction screw 131 and the second X-direction pad 132, the position of the second mounting ring 12 can be precisely adjusted in the X-direction.

[0058] The second Y-axis adjustment structure 14 includes a second Y-axis screw 141 and a second Y-axis pad 142, which are located on either side of the second mounting ring 12 in the Y direction. The second Y-axis screw 141 is threadedly connected to the second housing 11, and the end of the second Y-axis screw 141 abuts the second mounting ring 12. A steel ball can be positioned at the end of the second Y-axis screw 141, and a high-strength baffle can be installed at the corresponding position on the second mounting ring 12 to ensure both precision and strength. The second Y-axis pad 142 can be an L-shaped plate, which has elastic deformation and recovery properties and good support capacity.

[0059] When the second Y-direction screw 141 is tightened, the second mounting ring 12 can be pushed to move toward the second Y-direction pad 142. The second Y-direction pad 142 itself is elastic and can be compressed to provide abutment force to ensure the stability of the Y-direction position of the second mounting ring 12; when the second Y-direction screw 141 is loosened, the second mounting ring 12 is pushed to reset under the action of the elastic force of the second Y-direction pad 142. Therefore, through the cooperation of the second Y-direction screw 141 and the second Y-direction pad 142, the position of the second mounting ring 12 can be accurately adjusted in the Y-direction.

[0060] In one embodiment, a motorized module is also included to enable refined adjustment of the spot ring power ratio. The motorized module includes a first module for driving the rotation of the rotating assembly 3, a second module for driving the radial adjustment of the first adjustment assembly 2, and a third module for driving the radial adjustment of the second adjustment assembly 1. In high-precision laser processing applications, the configuration of the motorized module can achieve refined power adjustment in conjunction with the motion of the processing equipment, further improving the convenience and accuracy of adjustment.

[0061] The adjustment device of the present invention can shape the input Gaussian light beam into a Gaussian light spot of diffraction-limited size at the focus of the applied optical path system and concentric annular light spots distributed around it. By rotating the other DOE in the device relative to one of the DOEs, that is, changing the relative angle of the two DOEs on the circumference, the power ratio between the annular light spot and the Gaussian light spot of diffraction-limited size can be adjusted and controlled within the entire range, thereby realizing stepless adjustment of the power ratio of the Gaussian light spot and the annular light spot.

[0062] The point-ring power ratio stepless adjustment device based on phase modulation is a second-order phase and can be manufactured using liquid crystal lithography orientation technology and etching technology. The diffraction efficiency in the point state is greater than 99%, the diffraction efficiency in the ring state is about 80%, and the diffraction efficiency under the coexistence of point and ring is 80% to 100%, with high-order existence. However, the device has simpler requirements for mechanical eccentricity tolerance and debugging process. The eccentricity requirement of the Gaussian light source incident on the first DOE (i.e., the second diffractive optical element 5) is 0.1mm, and the relative eccentricity requirement of the two DOEs is 0.1mm, which is more in line with the optical path error requirements of industrial laser processing. In addition, the core optical elements of the adjustment device (two DOEs, i.e., the first diffractive optical element 4 and the second diffractive optical element 5) are manufactured based on the etching process. The samples manufactured by the etching process have a high damage threshold and can cover the current mainstream laser power of the 3D printing SLM process.

[0063] The operation process of the regulating device of the present invention is as follows:

[0064] The Gaussian light source emitted from the laser after beam expansion and collimation is first incident on the second diffractive optical element 5 of the adjustment device. The X and Y direction displacement adjustment of the second mounting ring 12 is achieved by adjusting the second X-direction screw 131 and the second Y-direction screw 141 in the second adjustment component 1 to ensure that the second diffractive optical element 5 is coaxial with the incident Gaussian light source.

[0065] The diffracted light emitted from the second diffractive optical element 5 is then emitted through the first diffractive optical element 4. The X and Y direction displacement adjustment of the first mounting ring 22 is achieved by adjusting the first X-direction screw 241 and the first Y-direction screw 251 in the first adjustment component 2 to ensure that the first diffractive optical element 4 and the second diffractive optical element 5 are optically coaxial.

[0066] The adjustment device cooperates with the actual application light beam and rotates the second diffractive optical element 5 to realize a point ring (focused Gaussian beam and concentric annular spot) with stepless power ratio adjustment at a certain size ratio on the processing surface.

[0067] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A point-loop power ratio stepless adjustment device based on phase modulation, characterized in that: include: a first diffractive optical element and a second diffractive optical element, wherein the first diffractive optical element and the second diffractive optical element are coaxially arranged and can be relatively rotated and adjusted; a surface of the second diffractive optical element away from the first diffractive optical element as an incident surface, and a surface of the first diffractive optical element away from the second diffractive optical element as an exit surface; The first diffractive optical element and the second diffractive optical element are based on phase modulation. At a first angle, the emergent light from the emergent surface is focused into a point state after passing through the applied optical path. At a second angle, it is focused into a ring state. Between the first angle and the second angle, it is a point and ring coexistence state.

2. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 1, characterized in that: The second diffractive optical element has the same phase structure as the first diffractive optical element, is arranged opposite to each other, and has a phase of 0 / pi in both radial and circumferential directions and is repeated periodically.

3. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 1, characterized in that: The optical system further includes a rotating assembly, a first adjusting assembly and a second adjusting assembly, wherein the second diffractive optical element is mounted on the rotating assembly, the rotating assembly is rotatably connected to the first adjusting assembly, the first diffractive optical element is mounted on the first adjusting assembly, the first adjusting assembly is used to adjust the radial position of the first diffractive optical element, the first adjusting assembly is connected to the moving part of the second adjusting assembly, and the second adjusting assembly is used to adjust the radial position of the second diffractive optical element.

4. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 3, characterized in that: The rotating assembly includes a rotating shell and a second limiting ring. The second diffractive optical element is installed in the rotating shell. The second limiting ring is used to limit the axial position of the second diffractive optical element. The rotating shell is rotatably connected to the fixed part of the first adjustment assembly.

5. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 4, characterized in that: The rotating shell has a rotating connection portion and a rotating portion. The rotating connection portion is used to be rotationally connected to the fixing portion of the first adjusting assembly, and the rotating portion is used for a rotating operation.

6. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 3, characterized in that: The first adjustment assembly includes a first shell, a first mounting ring, a first limiting ring, a first X-direction adjustment structure and a first Y-direction adjustment structure. The first diffractive optical element is installed in the first mounting ring and is axially limited by the first limiting ring. The first mounting ring is located in the first shell. The first X-direction adjustment structure is used to adjust the first mounting ring in the X direction, and the first Y-direction adjustment structure is used to adjust the first mounting ring in the Y direction.

7. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 6, characterized in that: The first X-direction adjustment structure includes a first X-direction screw and a first X-direction pad, and the first X-direction screw and the first X-direction pad are respectively located on both sides of the X-direction of the first mounting ring, and the first X-direction screw is threadedly connected to the first shell; the first Y-direction adjustment structure includes a first Y-direction screw and a first Y-direction pad, and the first Y-direction screw and the first Y-direction pad are respectively located on both sides of the Y-direction of the first mounting ring, and the first Y-direction screw is threadedly connected to the first shell.

8. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 6, characterized in that: The second adjustment assembly includes a second shell, a second mounting ring, a second X-direction adjustment structure and a second Y-direction adjustment structure. The first shell is connected to the second mounting ring, and the second mounting ring is located in the second shell. The second X-direction adjustment structure is used to adjust the second mounting ring in the X direction, and the second Y-direction adjustment structure is used to adjust the second mounting ring in the Y direction.

9. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 8, characterized in that: The second X-direction adjustment structure includes a second X-direction screw and a second X-direction pad, and the second X-direction screw and the second X-direction pad are respectively located on both sides of the X-direction of the second mounting ring, and the second X-direction screw is threadedly connected to the second shell; the second Y-direction adjustment structure includes a second Y-direction screw and a second Y-direction pad, and the second Y-direction screw and the second Y-direction pad are respectively located on both sides of the Y-direction of the second mounting ring, and the second Y-direction screw is threadedly connected to the second shell.

10. The phase modulation-based point-loop power ratio stepless adjustment device according to claim 3, characterized in that: It also includes an electric module, which includes a first module for driving the rotating component to rotate, a second module for driving the first adjusting component to adjust radially, and a third module for driving the second adjusting component to adjust radially.

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