A laser engraving system and method based on vector graphics structure and light field modulation

Abstract

The application discloses a laser engraving system and method based on a vector graph structure and light field modulation, and relates to the fields of optics and laser processing. The system mainly comprises a laser, a light beam shaping and polarization modulation module, a light beam modulation module and an objective. The application obtains basic constituting shapes, sizes and position information of a structure to be processed by analyzing vector graph information, and then designs a corresponding spatial light modulator holographic phase diagram. The spatial light modulator loads the holographic phase diagram to perform phase modulation in a laser processing system, and directly generates vector light spots (including but not limited to points, line segments, circles, ellipses, curves) corresponding to the basic shapes on a focusing plane of the objective. The basic structures are directly engraved on a material in a full-automatic manner, planar processing of a complex structure is realized, three-dimensional processing of the complex structure is realized by combining with layer-by-layer processing technology, processing uncertainty is significantly reduced, and processing efficiency, precision, consistency and smoothness are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optics and laser processing, and particularly relates to a high-speed laser direct printing system and method based on vector graph structure and light field modulation. BACKGROUND

[0002] In the prior art, when processing a structure, a graph of the structure to be processed is first read in, then the graph is converted into point cloud information of coordinates, and finally the point cloud of coordinates to be processed is irradiated by laser point by point, so as to process the desired planar structure. For a three-dimensional structure, the planar structure is processed layer by layer, and finally the three-dimensional structure is processed.

[0003] Usually, a spot used in laser processing is a small point spot (such as a Gaussian beam, a Bessel Gaussian beam, etc.), and in the process of processing point by point, due to the influence of the positioning accuracy, positioning jitter and processing time control accuracy of the laser focal point, it is inevitable to affect the uniformity, consistency and smoothness of the structure surface of the processed structure. SUMMARY

[0004] Therefore, it is necessary to provide a laser printing system and method based on vector graph structure and light field modulation in view of the above technical problems.

[0005] A laser printing system based on vector graph structure and light field modulation comprises a laser, a beam shaping and polarization modulation module, a beam modulation module and an objective lens.

[0006] The laser emits a corresponding laser beam which is incident to the beam shaping and polarization modulation module. The laser beam which is shaped and adjusted in polarization state by the beam shaping and polarization modulation module is incident to the beam modulation module. The beam modulation module loads a holographic phase map of a basic shape of a structure to be processed according to a processing flow in real time to generate a vector spot corresponding to a vector processing path. The modulated vector spot is incident to a back aperture plane of the objective lens. The objective lens focuses the light beam incident to the back aperture plane to converge on the structure to be processed to realize laser printing of the structure to be processed.

[0007] Further, the beam modulation module is a reflective phase spatial light modulator.

[0008] Further, the shaping and polarization state adjustment comprises spatial light filtering, beam expanding and polarization state adjustment.

[0009] Further,

[0010] The laser beam which is expanded by the beam shaping and polarization modulation module is incident to the beam modulation module through a first mirror.

[0011] The modulated laser beam passes through a small aperture diaphragm and a dichroic mirror in sequence and is incident on the rear aperture plane of the objective; the small aperture diaphragm is used to block the zero-order light spot generated by the beam modulation module; the dichroic mirror is used to reflect the modulated vector light spot and transmit the fluorescent light emitted by the photoresist; the fluorescent light is incident on the camera through the second reflector, and the camera is used to observe the photoetching structure in real time;

[0012] The system further comprises a translation stage for moving the position of the structure to be processed in space;

[0013] The system further comprises a control system for controlling the beam modulation module to load the holographic phase map in real time according to the processing flow to generate a vector light spot corresponding to the vector processing path.

[0014] A laser engraving method based on vector graph structure and light field modulation, comprising:

[0015] The laser emits a laser beam;

[0016] The laser beam is shaped and polarized;

[0017] The shaped and polarized laser beam is modulated by the beam modulation module, and the holographic phase map of the basic shape of the structure to be processed is loaded in real time according to the processing flow to generate a vector light spot corresponding to the vector processing path;

[0018] The vector light spot is converged on the structure to be processed to realize laser engraving of the structure to be processed.

[0019] Further, the generation of the holographic phase map specifically comprises:

[0020] The vector graph of the structure to be processed is analyzed in size and structure; the analysis in size is to analyze the complex vector graph into n partitions, and the analysis in structure is to analyze the complex vector graph into basic shapes;

[0021] The structure partitions are matched with the vector graph to find corresponding basic shapes, and the basic shape holographic phase map is generated through the basic shapes, positions and directions.

[0022] Further, the generation of the holographic phase map further comprises:

[0023] For a curve passing through two partitions, the position of the boundary point is calculated through the curve function, the position of the boundary point is taken as a new end point of the curve in one partition, the curve function of the part of the curve in one partition is regenerated combining the start point, and the position of the boundary point is taken as a new start point of the curve in another partition, the curve function of the part of the curve in another partition is regenerated combining the end point or another boundary point.

[0024] Further,

[0025] The basic shape includes: a circular shape, an elliptical shape, a straight line shape, an arc shape, a point shape;

[0026] The basic shape holographic phase diagram includes: a circular phase diagram, an elliptical phase diagram, a straight line phase diagram, an arc phase diagram, and a point phase diagram;

[0027] Wherein, a plurality of basic shapes can be generated simultaneously by one holographic phase diagram.

[0028] Further, the generation of the basic shape holographic phase diagram comprises:

[0029] The point light spot phase diagram is obtained by the Bessel Gaussian beam phase;

[0030] The straight line phase diagram is obtained by increasing the rotation transformation through the Airy light spot;

[0031] The arc phase diagram is obtained by combining the perfect vortex light spot with the discrete phase;

[0032] The closed curve phase diagram is obtained by splicing the arc light spot.

[0033] Further, the converging of the vector light spot to the structure to be processed to realize the laser marking of the structure to be processed comprises:

[0034] When processing the structure to be processed, the laser is turned on, the holographic phase diagram is loaded on the beam modulation module in a certain time sequence and the laser energy is adjusted in real time, the processing of the pattern in a structure partition is completed, and the laser is turned off.

[0035] The structure to be processed is horizontally moved to the next structure partition, the processing of the pattern in the next structure partition is completed, and the processing of a single layer plane is repeated.

[0036] The structure to be processed is vertically moved, and the processing of the pattern in each structure partition on the plane is completed, and the processing of a three-dimensional structure is repeated.

[0037] The above-mentioned high-speed laser direct marking system and method based on vector graph structure and light field modulation provided by the embodiment of the application have the following beneficial effects compared with the prior art:

[0038] The present application combines the method of light field regulation technology and vector path to decompose a complex pattern (glare spot structure, such as a circle, a line segment, an arc, etc. which can be freely defined in shape and size) into basic shapes, and then processes and synthesizes the complex pattern according to the basic shapes. This technology changes the previous point processing process to direct printing or engraving of the structure, which greatly improves the processing efficiency, precision, consistency and smoothness. That is, the present application can directly process the complex structure composed of basic shapes, significantly reduces the processing uncertainty caused by point-by-point processing, greatly improves the processing efficiency, precision, consistency and smoothness, which has a revolutionary significance in macro processing and micro processing technology. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 A high-speed laser direct engraving system structure schematic diagram based on vector graph structure and light field modulation is provided in one embodiment.

[0040] Figure 2 A complex vector image analysis and vector path processing flowchart is provided in one embodiment.

[0041] Figure 3 An objective lens focusing area point type light spot (a), straight line type light spot (b), arc type light spot (c), circular type light spot (d), elliptical type light spot (e) simulation phase diagram and light intensity distribution diagram are provided in one embodiment.

[0042] Figure 4 A complex pattern synthesis simulation result diagram using basic vector light spots is provided in one embodiment. Fig. (a) is a pattern simulation light intensity distribution diagram processed point by point; Fig. (b) is a simulation light intensity distribution diagram of the same structure as Fig. (a) based on vector graph structure and light field modulation processing; Fig. (c) is a simulation light intensity diagram of fingerprint structure based on vector graph structure and light field modulation processing; and Fig. (d) is a simulation light intensity diagram of complex pattern based on vector graph structure and light field modulation processing. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0044] Embodiment 1

[0045] As Figure 1The application discloses a high-speed laser direct printing system based on a vector diagram structure and light field modulation. The system comprises a femtosecond laser (Coherent, Chameleon Ultra II) 1, a beam shaping and polarization modulation module (OptoSigma, SFB-16DM) 2, a mirror 3, a liquid crystal spatial light modulator (LETO, HOLOEYE Photonics AG, Germany, PLUTO-NIR-011, 420nm-1100nm) 4, a pinhole diaphragm 5, a dichroic mirror 6, an objective lens (Olympus, NA1.25, 100X) 7, a translation stage (PI, E-712.6CDA) 8, a control system 9, a computer 10, a white light source 11, a mirror 12 and a camera 13. Specifically:

[0046] The laser emits a light beam of a corresponding wavelength, and the light beam is incident to the beam shaping and polarization modulation module. The light beam after the shaping and polarization modulation is reflected by the mirror and then is incident to the beam modulation module. The modulated light beam is incident to an entrance pupil plane of the objective lens through the dichroic mirror.

[0047] The beam shaping and polarization modulation module adjusts the shaping and polarization state of the light beam emitted by the laser, for example, performs spatial light filtering, beam expansion and polarization state adjustment on the light beam.

[0048] The beam modulation module modulates the incident light beam and then the modulated light beam is incident to the entrance pupil plane of the objective lens. The objective lens converges the light beam on the entrance pupil plane to the material to be processed. The beam modulation module is a reflective phase spatial light modulator used to generate a basic vector light spot in real time.

[0049] The pinhole diaphragm is used to block the zero-order light spot generated by the beam modulation module.

[0050] The mirror reflects the light beam so that the light beam is incident to the reflective phase spatial light modulator and the entrance pupil of the objective lens respectively.

[0051] The translation stage is used to move the position of the structure to be processed in space.

[0052] The dichroic mirror is used to reflect the modulated vector light spot and transmit the fluorescent light emitted by the photoresist.

[0053] The control system is used to control the micron-nanometer translation stage to move according to a corresponding region and control the spatial light modulator to load a holographic phase diagram in real time according to a processing procedure, so that a vector light spot corresponding to a processing path is generated.

[0054] The camera is used to observe the photoetching structure in real time.

[0055] Embodiment 2

[0056] This invention provides a high-speed laser direct imprinting method based on vector graphic structure and light field modulation, the method comprising the following steps:

[0057] Step 1: The laser emits laser light of the corresponding wavelength and directs it to the beam shaping and polarization modulation module.

[0058] Step 2: The beam shaping and polarization modulation module shapes and adjusts the polarization state of the incident laser beam, such as performing spatial light filtering, beam expansion, and polarization state adjustment on the beam; the adjusted beam is then incident on the beam modulation module via a reflector.

[0059] Step 3: The beam modulation module modulates the shaped laser beam to generate the required vector spot, which is then reflected by a dichroic mirror to the entrance pupil plane of the objective lens.

[0060] Further, see Figure 2 In step three, the shaped laser beam is modulated, including the following steps:

[0061] Step 301: First, analyze the vector diagram of the structure to be processed. The analysis is divided into analyzing the dimensions and analyzing the structure.

[0062] Furthermore, the vector graphic after resolution is partitioned according to the optical system (including parameters such as the light source, objective lens, and spatial light modulator used), thus resolving the complex vector graphic into n partitions.

[0063] Furthermore, the analytical structure involves analyzing the basic graphics in a vector graphic. By using the analytical structure, complex vector graphics can be broken down into basic shapes, such as circles, ellipses, lines, arcs, and dots. Figure 4 Taking the graphic shown in (b) as an example, the analytical structure involves analyzing the basic graphics in the vector graphic. Figure 4 (b) The vector diagram shows two basic structures: circles and arcs.

[0064] Step 302, then... Figure 4 (b) Processing of a structural partition (structural partition 1): For this partition, a circular shape is found by matching vector graphics. The corresponding holographic phase map is generated based on the circular shape, position, and orientation. The basic graphic distribution of this partition includes phase maps of basic graphics such as circular spot phase maps, linear spot phase maps, arc-shaped spot phase maps, and elliptical spot phase maps; Figure 4 (b) The basic graphic distribution of a structural partition (structural partition 1) contains a phase map of a circular graphic.

[0065] Step 303, similarly, move the structure partition to structure partition 2 by the translation table, find the corresponding basic shape by matching the vector graph for this partition, and the processing of other partitions in the complex vector graph is the same as step 302. Then process structure partition 2, find the corresponding arc-shaped shape by matching the vector graph for this partition, and the processing of other partitions in the complex vector graph is the same as step 302. Then process structure partition 2, find the corresponding arc-shaped shape by matching the vector graph for this partition, and the processing of other partitions in the complex vector graph is the same as step 302. Figure 4 (b) The processing of other partitions in the graph is the same as step 302. For the curve passing through partition 1 and partition 2, the position of the boundary point can be calculated by the curve function, and the position of the boundary point is used as the new end point of the curve in partition 1, and the curve function of the part of the curve in partition 1 is regenerated in combination with the starting point. At the same time, the position of the boundary point is used as the new starting point of the curve in partition 2, and the curve function of the part of the curve in partition 2 is regenerated in combination with the end point (or another boundary point).

[0066] Step 304, generate a series of phase maps to be loaded for the structures in all partitions; and Figure 4 (b) After all the partitions in (b) are processed, a series of phase maps to be loaded are generated.

[0067] Step 305, determine whether the series of phase maps to be loaded meet the maximum loading capacity of the hologram loading software. If yes, proceed to the next step; if not, perform segmented loading on the series of phase maps. After processing these partitions, load the phase maps used by the subsequent partitions.

[0068] Further, in step 303, the phase map of the basic graph includes the following steps:

[0069] Step 303_1, the point-shaped light spot phase map is obtained from the Bessel Gaussian beam phase, and the phase distribution expression is:

[0070]

[0071] Where k is the spatial frequency in vacuum, η is the radius of the axicon, and r is the radial coordinate;

[0072] Step 303_2, the straight line-shaped light spot is obtained by increasing the rotation transformation of the Airy light spot, and the corresponding expression is:

[0073]

[0074] Where k x , k y is the spatial frequency, k′ x and k′ y are the transformed spatial frequencies, and the phase expression of the straight line-shaped light spot is:

[0075]

[0076] where a is the attenuation factor of the Airy beam.

[0077] Step 303_3, the arc-shaped light spot is obtained by combining the perfect vortex light spot with the discrete phase, and for any arc of the arc-shaped light spot, the x, y coordinate ratio and the rotation matrix can be changed to obtain the arc-shaped light spot.

[0078] Step 304_4, the closed curve can be obtained by splicing the arc-shaped light spot, and the special cases include that the circular light spot is generated by the perfect vortex light obtained by the axicon phase, the diameter of the perfect vortex light spot can be adjusted by adjusting the base angle of the axicon, and the elliptical light spot can be obtained by rotating the perfect vortex light spot by a rotation matrix or by splicing the arc-shaped light spot.

[0079] Step 303_5, Figure 4 The phase pattern of the circular light spot in (b) is obtained from the perfect vortex phase, and the corresponding expression is:

[0080]

[0081] where l is the topological charge number, is the azimuth angle, η is the axicon parameter, and r is the transverse coordinate.

[0082] Step 303_2, Figure 4 The arc-shaped light spot shown in (b) is obtained by combining the perfect vortex light spot with the discrete phase, and for any arc of the arc-shaped light spot, the x, y coordinate ratio and the rotation matrix can be changed to obtain the arc-shaped light spot.

[0083] Step 304_3, Figure 4 The closed curve in (b) is obtained by splicing the arc-shaped light spot.

[0084] Step four, the light beam modulated in step three is reflected to the objective entrance pupil plane by the dichroic mirror and then converged to the structure to be processed by the objective. The material to be processed is processed, including the following steps:

[0085] Step 401, turn on the laser, and load Figure 4 (b) the decomposed vector diagram sequence to the light field regulation software, adjust the laser energy according to the currently loaded phase pattern, complete the processing of one image, then load the next phase pattern, adjust the laser energy, complete the processing of the next image, repeat the foregoing process until the processing of all images in the structure partition is completed, and then turn off the laser.

[0086] Step 402, control the system to move the translation stage to the next structure partition, and repeat step 401.

[0087] Step 403, repeat steps 401 and 402 to realize the processing of a single layer plane (two-dimensional processing), that is, to realize the processing ofFigure 4 (b) processing of the graphics.

[0088] Step five, the control system controls the translation stage to move vertically, and step four is repeated to realize three-dimensional structure processing.

[0089] Step six, finally, the curve approximation method can be used to repair the partition boundary as needed to make the processed structure more complete, smooth and consistent.

[0090] As Figure 3 shown is the basic light spot phase diagram corresponding to the vector path generated by the application and the corresponding light intensity distribution diagram.

[0091] Figure 4 The simulation result diagram of the complex pattern synthesized by the basic vector light spot, wherein figure (a) is the simulation light intensity distribution diagram of the pattern processed point by point, figure (b) is the simulation light intensity diagram of the fingerprint structure processed based on the vector diagram structure and the light field modulation, figure (d) is the simulation light intensity diagram of the complex pattern processed based on the vector diagram structure and the light field modulation, and the basic vector light spot can be used to quickly generate the processing of such complex patterns. From the comparison between simulation diagrams (a) and (b), we can see that the former is significantly lower than the latter in processing efficiency, and due to the influence of interference between light beams, the control system cannot be accurately positioned, and other factors lead to poor processing quality. Therefore, the high-speed laser direct printing technology based on the vector diagram structure and the light field modulation proposed by the application significantly reduces the processing uncertainty generated by point-by-point processing, greatly improves the processing efficiency, precision, consistency and smoothness, which has a revolutionary significance in macro processing and micro processing technology, and can be used as the next generation technology prototype in the field of laser processing.

[0092] In summary, the embodiment of the application provides a high-speed laser direct printing method and system based on a vector diagram structure and light field modulation, which obtains the basic constituent shape, size and position information of the structure to be processed by analyzing the vector diagram information, and then designs the corresponding spatial light modulator holographic phase diagram. The holographic phase diagram is loaded into the spatial light modulator in the laser processing system to perform phase modulation, and the vector light spot (including but not limited to point, line segment, circle, ellipse, curve, etc.) corresponding to the basic shape is directly generated on the focusing plane of the objective lens. Then the basic structure is directly printed on the material automatically to realize planar processing of complex structures, and finally combined with layer-by-layer processing technology, three-dimensional processing of complex structures is realized, which significantly reduces the processing uncertainty and greatly improves the processing efficiency, precision, consistency and smoothness. The method and system proposed by the application can be well applied to the fields of industrial manufacturing, micro-nano manufacturing and material manufacturing.

[0093] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific and detailed manner, but should not be construed as limiting the scope of the patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these are all within the scope of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. A laser engraving system based on vector graphics structure and light field modulation, characterized in that, The system is used for decomposing a complex pattern into basic shapes and processing the complex pattern according to the basic shapes; the system comprises a laser, a beam shaping and polarization modulation module, a beam modulation module, a pinhole diaphragm, a dichroic mirror, an objective lens, a second mirror and a camera. The laser emits a corresponding laser beam which is incident on the beam shaping and polarization modulation module, the laser beam which is shaped and has a polarization state adjusted by the beam shaping and polarization modulation module is incident on the beam modulation module, the beam modulation module loads a holographic phase pattern of a basic shape of a material to be processed into the laser beam in real time according to a processing procedure to generate a light spot structure corresponding to a vector processing path, the modulated light spot structure is incident on a rear aperture plane of the objective lens, the objective lens focuses the light beam incident on the rear aperture plane to converge on the material to be processed to realize laser engraving of the material to be processed. The laser beam modulated by the beam modulation module is sequentially incident on the rear aperture plane of the objective lens through the pinhole diaphragm and the dichroic mirror; the pinhole diaphragm is used to block the zero-order light spot generated by the beam modulation module; the dichroic mirror is used to reflect the modulated light spot structure and transmit fluorescent light emitted by photoresist; the fluorescent light is incident on the camera through the second mirror, and the camera is used to observe the photoetching structure in real time. The generation of the holographic phase pattern specifically comprises: analyzing the size and structure of a vector pattern of the material to be processed; the analysis of the size comprises analyzing the complex vector pattern into n partitions, and the analysis of the structure comprises analyzing the complex vector pattern into basic shapes; a corresponding basic shape is found by matching the vector pattern for the structural partition, and a corresponding holographic phase pattern is generated by the basic shape, position and direction; a plurality of basic shapes can be generated simultaneously by one holographic phase pattern.

2. The laser engraving system based on vector graphics structure and light field modulation of claim 1, wherein, The beam modulation module is a reflective phase spatial light modulator.

3. The laser engraving system based on vector graphics structure and light field modulation of claim 1, wherein, The shaping and polarization state adjustment comprises spatial light filtering, beam expanding and polarization state adjustment.

4. The laser engraving system based on a vector pattern structure and light field modulation according to claim 1, wherein the laser beam expanded by the beam shaping and polarization modulation module is incident on the beam modulation module through the first mirror; the system further comprises a translation stage which is used to move the position of the material to be processed in space; the system further comprises a control system which is used to control the beam modulation module to load the holographic phase pattern into the laser beam in real time according to the processing procedure to generate the light spot structure corresponding to the vector processing path.

5. A laser engraving method based on the laser engraving system based on vector graphics structure and light field modulation according to claims 1-4, characterized in that, The system comprises: a laser which emits a laser beam; the laser beam is shaped and has a polarization state adjusted; the laser beam which is shaped and has a polarization state adjusted is modulated by the beam modulation module, a holographic phase pattern of a basic shape of a material to be processed is loaded into the laser beam in real time according to a processing procedure to generate a light spot structure corresponding to a vector processing path; the light spot structure is converged on the material to be processed to realize laser engraving of the material to be processed.

6. The laser engraving method of the laser engraving system based on a vector graphic structure and a light field modulation according to claim 5, characterized in that, The generation of the holographic phase pattern further comprises: For the curve crossing two sub-zones, the position of the boundary point is calculated by the curve function, the position of the boundary point is taken as the new end point of the curve in one sub-zone, the curve function of the part of the curve in one sub-zone is regenerated combining the start point, and the position of the boundary point is taken as the new start point of the curve in another sub-zone, the curve function of the part of the curve in another sub-zone is regenerated combining the end point or another boundary point. 7.The laser engraving method based on the vector graphic structure and the light field modulation of claim 5, wherein, the basic shape includes: a circular shape, an elliptical shape, a straight line shape, an arc line shape, and a point shape; the basic shape holographic phase map includes: a circular phase map, an elliptical phase map, a straight line phase map, an arc line phase map, and a point phase map.

8. The laser engraving method of the laser engraving system based on a vector graphic structure and a light field modulation according to claim 7, characterized in that, the generation of the basic shape holographic phase map includes: the point phase map is obtained by a Bessel Gaussian beam phase; the straight line phase map is obtained by an Airy beam by adding a rotation transformation; the arc line phase map is obtained by a perfect vortex beam combining a discrete phase; the closed curve phase map is obtained by arc line beam splicing.

9. The laser engraving method of the laser engraving system based on a vector graphic structure and light field modulation according to claim 5, characterized in that, the converging of the spot structure to the material to be processed to realize laser engraving of the material to be processed includes: when processing the material to be processed, the laser is turned on, the holographic phase map is loaded on the beam modulation module in a certain time sequence and the laser energy is adjusted in real time, the processing of the pattern in one structure sub-zone is completed, and the laser is turned off; the material to be processed is moved horizontally to the next structure sub-zone, the processing of the pattern in the next structure sub-zone is completed, and all structure sub-zones are repeated to realize the processing of a single layer plane; the material to be processed is moved vertically, and the processing of the pattern in each structure sub-zone on this plane is completed; all layer structure sub-zones are repeated to realize three-dimensional structure processing.

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