A two-photon automatic processing method, system and device for non-flat substrates

Abstract

The present invention relates to a two-photon automatic processing method, system and equipment for non-flat substrates. The processing method comprises the following steps: S1: adjusting the horizontal position of the substrate so that the horizontal position of the laser focus is located within the initial processing area of ​​the substrate; S2: focusing the laser, and performing laser processing at the initial processing position after focusing; S3: moving the substrate to the next processing point, focusing at the processing point, and performing laser processing at the processing point after focusing; S4: repeating S3 until all processing points are processed, developing the processed micro-nano structure, and obtaining a finished micro-nano structure. The present invention solves the problem that manual focusing operation is complicated, time-consuming and has large errors during processing on a non-flat substrate using a laser by automatically focusing each processing point.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a two-photon automatic processing method for a non-flat substrate, a two-photon automatic processing system for a non-flat substrate, and a two-photon automatic processing device for a non-flat substrate. Background Art

[0002] Femtosecond laser micro-nano processing is an emerging nanostructure forming method. It can be regarded as a special 3D printing, namely, photocuring technology. During the focusing process of femtosecond laser two-photon direct writing processing, the staff needs to find the interface between the two-photon material and the substrate as the processing reference surface. The relative position of the two-photon processing material and the laser focus on the substrate is controlled by controlling the three-dimensional motion table. When a suitable processing reference surface is found, the two-photon material is directly processed by femtosecond laser two-photon.

[0003] When the laser focus deviates from the processing reference plane, two situations will occur: a) When the laser focus is mostly in the substrate material, the processed structure is incomplete compared to the designed structure, and part of the processed structure is lost after development. b) When the focus is completely in the polymer material, the processed structure will not be connected to the substrate, and the processed structure will be washed away after development, resulting in complete loss of the structure.

[0004] During the processing, non-flat substrates can be roughly divided into three situations: 1. Flexible substrates (such as Figure 1 .a). 2. Patterned substrate (e.g. Figure 1 .b). 3. Tilt the base (e.g. Figure 1 .c).

[0005] Using femtosecond laser to process micro-nano structures on flexible substrate materials (such as Figure 2 .a). Due to the irregular changes in the substrate surface morphology, the subsequent micro-nanostructures are lost or completely lost after the initial position focusing is completed (e.g. Figure 2 .b). Currently, the staff manually refocuses after processing a structure and then continues to process the next structure (such as Figure 2 .c) Solve this problem. However, this method is cumbersome to operate, and manual focusing is to determine the focal axial position by observing the size of the light spot when the laser interacts with the material to be processed with the naked eye. There is a large random error in naked eye observation, which affects the processing quality. Summary of the invention

[0006] Based on this, it is necessary to address the problems of complicated manual focusing operation, long time consumption and large error in the existing laser processing on non-flat substrates. A two-photon automatic processing method, system and equipment for non-flat substrates are proposed.

[0007] The present invention is implemented by the following technical solution: A two-photon automatic processing method for a non-flat substrate, comprising the following steps:

[0008] S1: Adjust the horizontal position of the substrate so that the horizontal position of the laser focus is located in the initial processing area of ​​the substrate. The initial processing area indicates that when any point in the area is selected as the initial processing point, the horizontal area where the design structure is located is located on the substrate.

[0009] S2: focusing the laser so that the substrate is located at an ideal initial processing position, and laser processing is performed at the initial processing position according to a corresponding processing strategy. The focusing method is as follows:

[0010] S21: Taking the fluorescent polymer as the object of framing, collecting the spot image of the scattered fluorescence of the fluorescent polymer in real time.

[0011] S22: adjusting the height of the substrate, and when the equivalent diameter of the light spot in the light spot image reaches a maximum value, calculating the maximum equivalent diameter of the light spot as a reference value.

[0012] S23: Calculate the ideal value of the equivalent diameter of the light spot based on the physical properties of the fluorescent polymer and the benchmark value.

[0013] S24: Adjust the height of the substrate until the equivalent diameter of the light spot in the light spot image is equal to the ideal value.

[0014] S3: Control the substrate to move to the next processing point according to the preset moving path, determine whether the equivalent diameter of the light spot in the light spot image is equal to the ideal value, and make the following decisions:

[0015] (1) If yes, laser processing is performed directly at this position.

[0016] (2) Otherwise, focusing is performed at the processing point, and after focusing is completed, laser processing is performed at the processing point.

[0017] S4: Determine whether the processing is completed. If the processing is not completed, repeat S3 until the processing is completed. If the processing is completed, develop the processed micro-nano structure to obtain a finished micro-nano structure.

[0018] The present invention solves the problem that manual focusing operation is complicated, time-consuming and has large errors during processing on a non-flat substrate using a femtosecond laser by automatically focusing each processing point.

[0019] In one embodiment, the initial processing area is calculated based on the horizontal area covered by the substrate and the horizontal area covered by the scanning strategy, and the specific method is as follows:

[0020] a. Change the shape of the base j , the shape of the laser focus l, horizontal area p covered by the machining strategy p and the horizontal area p covered by the scanning strategy s Mapped on the same plane. l and p p Concentric setting, and at p j Inner edge p p With p j The tangent path moves one circle. l With p j The area enclosed by p j Remove from the middle and get the intermediate shape p m .

[0021] b. for p m Scale until the scaled figure is just circumscribed on p s On. Let p m is an n-gon, circumscribed at p s The graph on is p ms , then p ms The n corners of the m Each time the corner is fitted, the other n-2 edges that are not adjacent to the fitted corner are extended. Multiple extension lines will s Divide into multiple sub-regions, including p m The sub-area of ​​each corner is used as the initial processing area.

[0022] In one embodiment, the method for determining whether the laser focus is within the initial processing area is as follows:

[0023] S11: Taking the substrate as a framing object, collecting a substrate image including the laser focus.

[0024] S12: pre-processing the substrate image to retain the outer contour of the substrate and the outer contour of the laser focus.

[0025] S13: Add the outline of the initial processing area to the outer contour of the substrate.

[0026] S14: Observe whether the outer contour of the laser focus is completely within the initial processing area, if yes, confirm that the laser focus is within the initial processing area. Otherwise, move the substrate until the outer contour of the laser focus is completely within the initial processing area.

[0027] In one embodiment, the method for obtaining the reference value is as follows:

[0028] S221: Observe whether there is a light spot in the initial light spot image, and make the following decisions: If there is no light spot, the substrate is raised or lowered until a light spot appears in the light spot image. If there is a light spot, the substrate is controlled to move up or down, and the size change of the light spot is observed.

[0029] S222: Determine whether the size of the light spot increases, and make the following decision: If the light spot gradually decreases, move the base in the opposite direction to increase the size of the light spot in the light spot image. If the light spot gradually increases, control the base to continue moving in the original direction until the size of the light spot remains unchanged. If the light spot remains unchanged, the equivalent diameter of the light spot reaches the maximum, and the minimum circumscribed circle of the light spot is obtained, and the diameter of the minimum circumscribed circle is the reference value.

[0030] In one embodiment, the movement of the substrate is three-dimensional, with the initial processing point as the origin, the vertical direction as the Z axis, any horizontal direction as the X axis, and another horizontal direction perpendicular to the X axis as the Y axis. Then the movement path only includes the movement of the substrate on the X axis and the Y axis, and the focusing process only includes the movement of the substrate on the Z axis.

[0031] The present invention also provides a two-photon automatic processing system for a non-flat substrate, comprising:

[0032] The imaging module is used for collecting the spot image containing the fluorescent polymer and its scattered fluorescence in real time.

[0033] The image processing module is used to preprocess the spot image and calculate the equivalent diameter of the spot in the spot image. The preprocessing of the spot image includes normalization and filtering. Normalization can convert each spot image into the same form, maintain the same standard during multiple processing, and improve the processing accuracy. Filtering can suppress the noise of the image while retaining the image details and improve the accuracy of image processing.

[0034] The decision module is used to: 1. determine whether the equivalent diameter of the light spot is the maximum value, if so, record the maximum value of the equivalent diameter as the reference value. 2. determine whether the equivalent diameter of the light spot is the ideal value, if so, confirm that the focus is completed.

[0035] The displacement control module is used to: Ⅰ. Output displacement signals according to the preset moving path, thereby controlling the motion stage to drive the substrate to move horizontally. Ⅱ. Output displacement signals according to the preset processing strategy, thereby controlling the motion stage to drive the substrate to move three-dimensionally. Ⅲ. Output lifting signals during focusing, thereby controlling the motion stage to drive the substrate to lift.

[0036] The present invention also provides a two-photon automatic processing device for a non-flat substrate, which comprises a laser, a motion stage, an optical path regulator, an objective lens, an imaging device and a controller.

[0037] The laser is used to emit laser light. The substrate is used to carry the fluorescent polymer so that the fluorescent polymer is located on the laser path and the fluorescent polymer produces a fluorescent effect when irradiated by the laser light. The moving platform is fixedly connected to the substrate and is used to drive the substrate to move. The substrate can be fixedly connected to the moving platform by means of magnetic attraction or the like to ensure that the substrate does not deviate when the moving platform drives the substrate to move.

[0038] The optical path regulator is arranged on the emission path of the laser, and is used to adjust the intensity and direction of the laser so that the laser can be used for processing or focusing respectively. The objective lens is arranged on the laser emission path of the optical path regulator, and is used to focus the laser. The imaging device is arranged on the fluorescence path scattered by the fluorescent polymer, and is used to collect the spot image containing the fluorescent polymer and its scattered fluorescence in real time. The imaging device is also used to transmit the collected spot image to the controller.

[0039] The controller is used to: 1. Control the motion stage to adjust the horizontal position of the substrate so that the horizontal position of the laser focus is located within the initial processing area of ​​the substrate. 2. Focus the laser emitted by the laser so that the substrate is located at the ideal initial processing position, and perform laser processing at the initial processing position according to the corresponding processing strategy. 3. Control the motion stage to drive the substrate to move according to the preset moving path, and then complete the corresponding laser processing at each processing point. 4. Determine whether the equivalent diameter of the spot in the spot image is equal to the ideal value. If so, perform laser processing directly at this position. Otherwise, focus at the processing point, and perform laser processing at the processing point after focusing.

[0040] In one embodiment, the optical path regulator includes an optical gate, a pre-regulator and a beam splitter. The pre-regulator is arranged on the laser emission path of the laser, and is used to adjust the energy and phase of the laser. The optical gate is arranged between the laser and the pre-regulator, and is used to control the on and off of the laser. The beam splitter is arranged on the laser emission path of the pre-regulator, and is used to reflect the processing laser and transmit the imaging light. The optical path regulator is used to adjust the energy and phase of the laser, so that the laser can be used for processing and focusing respectively, and the laser is divided into a transmitted light beam and a reflected light beam, so as to synchronously complete the laser focusing and the spot image acquisition, thereby improving the efficiency and accuracy of the laser focusing.

[0041] In one embodiment, the pre-regulator includes a Glan Taylor prism, a half-wave plate, a beam expander, a reflector, and an attenuation plate arranged in sequence along the laser emission path. The Glan Taylor prism is used to control the energy of the laser beam. The half-wave plate is used to adjust the phase of the laser beam. The beam expander is used to increase the diameter of the laser beam. The reflector is used to adjust the emission direction of the laser beam. The attenuation plate is used to adjust the energy of the laser beam.

[0042] In one embodiment, the laser is a femtosecond laser, the imaging device is a CCD camera, and the motion stage is a three-dimensional micro-nano motion stage.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The present invention solves the problem that manual focusing operation is complicated, time-consuming and has large errors when processing on a non-flat substrate using a femtosecond laser by automatically focusing each processing point.

[0045] 2. The present invention adopts a fluorescence focusing method, which converts the focusing of the laser focus into fluorescence image recognition, and confirms whether the focusing is completed according to the equivalent diameter of the light spot, thereby effectively improving the focusing efficiency and focusing accuracy.

[0046] 3. The present invention presets the initial processing area so that the micro-nano structure obtained by laser processing can be just on the substrate, avoiding partial loss of the micro-nano structure and improving processing efficiency.

[0047] 4. The three-dimensional micro-nano motion stage is used to drive the substrate to move, which can drive the substrate to move arbitrarily within a three-dimensional range, so that the laser processing equipment can complete complex three-dimensional structure processing, while improving the focusing accuracy and focusing efficiency of the processing equipment.

[0048] 5. Use an optical path regulator to adjust the energy and phase of the laser so that the laser can be used for processing and focusing respectively. At the same time, the laser is divided into a transmitted beam and a reflected beam to facilitate the synchronous completion of laser focusing and spot image acquisition, thereby improving the efficiency and accuracy of laser focusing. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a non-flat base classification diagram in the background technology of the present invention;

[0050] Figure 2 A distortion diagram of a three-dimensional micro-nano structure in the background technology of the present invention;

[0051] Figure 3 This is a flow chart of a two-photon automatic processing method for a non-flat substrate according to Embodiment 1 of the present invention;

[0052] Figure 4 for Figure 3 Get the intermediate shape p of the initial processing area m Schematic diagram of

[0053] Figure 5 for Figure 3 Schematic diagram of the angle fitting of the ideal initial processing area;

[0054] Figure 6 for Figure 3 Schematic diagram of the location of the ideal initial processing area;

[0055] Figure 7 for Figure 3 Schematic diagram of the actual angle fitting of the initial processing area;

[0056] Figure 8 for Figure 3 Schematic diagram of the actual location of the initial processing area;

[0057] Fig. 9 for Figure 3 Schematic diagram of the relationship between the relative position of the laser focus, the size change of the fluorescent spot, and the final processing result;

[0058] Fig.10 for Figure 3 Schematic diagram of the size of the fluorescent spot when the laser focus is located at different positions;

[0059] Fig.11 for Figure 3 Schematic diagram of the movement direction of the substrate;

[0060] Fig.12 To adopt Figure 3 A schematic diagram of a laser path of a two-photon automatic processing device for a non-flat substrate in a two-photon automatic processing method for a non-flat substrate;

[0061] Fig.13 The fluorescence color and micro-pillar array diagram of the laser focus at different heights relative to the substrate surface;

[0062] Fig.14 This is the fluorescence color and micro-pillar array image achieved after using autofocus;

[0063] Fig.15 This is a comparison chart of the experiments of processing micro-nano structures at different positions on the patterned substrate. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0065] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0067] Example 1

[0068] See also Figure 3 , which is a flow chart of the two-photon automatic processing method for non-flat substrates of this embodiment. The two-photon automatic processing method for non-flat substrates includes the following steps:

[0069] S1: Adjust the horizontal position of the substrate so that the horizontal position of the laser focus is located in the initial processing area of ​​the substrate. The initial processing area indicates that when any point in the area is selected as the initial processing point, the horizontal area where the design structure is located is located on the substrate.

[0070] In this embodiment, laser two-photon processing processes the fluorescent polymer to be processed into a micro-nano structure that matches the size of the designed structure on a substrate according to a design structure. In order to ensure that the laser-processed micro-nano structure is completely located on the substrate, it is necessary to locate the initial processing point of the laser processing. In this embodiment, the method of presetting the initial processing area on the substrate is adopted to locate the laser focus in the initial processing area, and then the laser two-photon processing is performed according to the initial processing point and the placement direction of the substrate, so that the processed micro-nano structure is completely located on the surface of the substrate.

[0071] Please combine Figures 4 to 8 , Figure 4 for Figure 3 Get the intermediate shape p of the initial processing area m Schematic diagram of Figure 5 for Figure 3 Schematic diagram of the angle fitting of the ideal initial processing area; Figure 6 for Figure 3 Schematic diagram of the location of the ideal initial processing area; Figure 7 for Figure 3 Schematic diagram of the actual angle fitting of the initial processing area; Figure 8 for Figure 3 The actual position diagram of the initial processing area in FIG. The initial processing area is calculated based on the horizontal area covered by the substrate and the horizontal area covered by the scanning strategy. The specific method is as follows:

[0072] a. The shape of the base p j , the shape of the laser focus l , horizontal area p covered by the machining strategy pand the horizontal area p covered by the scanning strategy s Mapped on the same plane. l and p p Concentric setting, and at p j Inner edge p p With p j The tangent path moves one circle. l With p j The area enclosed by p j Remove from the middle and get the intermediate shape p m .

[0073] In this embodiment, the substrate is in the form of a thin sheet, and the outer contour of the substrate is denoted as p j The laser focus is an ellipsoid, and forms an elliptical projection on the horizontal plane. The outer contour of the elliptical projection is denoted as p l The projection of the micro-nano structure processed at each processing point on the horizontal plane is denoted by p p In the scanning strategy, the polygon formed by all processing points is recorded as p m Taking the center of the laser focus as the processing center, if the processed micro-nano structure is completely placed on the substrate, then p p Not to exceed p j , so the initial processing area cannot be adjacent to the outer contour of the substrate.

[0074] b. for p m Scale until the scaled figure is just circumscribed on p s On. Let p m is an n-gon, circumscribed at p s The graph on is p ms , then p ms The n corners of the m Each time the corner is fitted, the other n-2 edges that are not adjacent to the fitted corner are extended. Multiple extension lines will s Divide into multiple sub-regions. m The sub-area of ​​each corner is used as the initial processing area.

[0075] Taking the rectangular base as an example, let the length of the base be l j , width is d j , the major axis of the elliptical projection of the laser focus is l l , the minor axis is d l If the horizontal area p covered by the machining strategy p and the horizontal area p covered by the scanning strategy s is also a rectangle, and p s The length is l s , width is d s , p pThe length is l p , width is d p Then p m The length and width are l m =(l j -l p +l l ) and d m =(d j -d p +d l ). The theoretical initial processing area includes four rectangles located at the four corners, and the length and width of each rectangle are (l m -l s ) and (d m -d s ). The initial processing area actually selected in this embodiment is, the width of each rectangle is [1-Max(l s / l m -d s / d m )]×l m and [1-Max(l s / l m -d s / d m )]×d m .

[0076] It can be seen that the theoretical initial processing area is larger than the actual selected initial processing area. j 、p p and p s When all are standard rectangles, the calculation of the theoretical initial processing area is not only simpler, but also has a larger area. j 、p p and p s When they are all non-standard rectangles, due to p m and p s The outer contours of the ms The angle and p m The corners are fitted and difficult to process directly. m Scaling is performed so that the p formed by scaling ms External in p s It greatly reduces the number of calculation steps and improves the efficiency of selecting the initial processing area.

[0077] Please combine Fig. 9 and Fig.10 , the method to determine whether the laser focus is within the initial processing area is as follows:

[0078] S11: With the substrate as the framing object, a substrate image including the laser focus is collected. Since the sizes of the substrate and the laser focus are both in the micron level, it is difficult to directly observe the position of the laser focus relative to the substrate with the naked eye. Therefore, by imaging the substrate, the position of the laser focus relative to the substrate image is observed to confirm whether the laser focus is located in the initial processing area.

[0079] S12: Preprocess the base image to retain the outer contour of the base and the outer contour of the laser focus. The preprocessing of the base image includes normalization and filtering. Normalization can convert the image into the same form, maintain the same standard during multiple processing, and improve the processing accuracy. Filtering can suppress the noise of the image while retaining the detailed features of the image, thereby improving the accuracy of image processing. The outer contours of the base and the laser focus can be obtained through an image recognition model. Converting image processing into mathematical graphics processing can simplify the processing process and improve processing accuracy.

[0080] S13: Add the outline of the initial processing area to the outer contour of the substrate. The initial processing area can be based on the outer shape of the substrate. j , the shape of the laser focus l , horizontal area p covered by the machining strategy p and the horizontal area p covered by the scanning strategy s Calculations are performed to add the initial processing area to the base image.

[0081] S14: Observe whether the outer contour of the laser focus is completely within the initial processing area, if yes, confirm that the laser focus is within the initial processing area. Otherwise, move the substrate until the outer contour of the laser focus is completely within the initial processing area.

[0082] By observing whether the laser focus is within the initial processing area through image processing, the accuracy of positioning the initial processing point can be effectively improved to avoid the processed micro-nano structure exceeding the surface of the substrate and causing partial structure loss.

[0083] S2: focusing the laser so that the substrate is located at an ideal initial processing position, and performing laser processing at the initial processing position according to a corresponding processing strategy.

[0084] Among them, the focusing method is as follows:

[0085] S21: Taking the fluorescent polymer as the object of framing, collecting the spot image of the fluorescent polymer scattered fluorescence in real time. The fluorescent polymer produces a fluorescent effect under laser irradiation, and the substrate is photographed in real time by an imaging device such as a camera. After video processing and image processing, the substrate image containing the fluorescent spot can be extracted.

[0086] S22: adjusting the height of the substrate, and when the equivalent diameter of the light spot in the light spot image reaches a maximum value, calculating the maximum equivalent diameter of the light spot as a reference value.

[0087] The method to obtain the benchmark value is as follows:

[0088] S221: Observe whether there is a light spot in the initial light spot image, and make the following decisions: If there is no light spot, the substrate is raised or lowered until a light spot appears in the light spot image. If there is a light spot, the substrate is controlled to move up or down, and the size change of the light spot is observed.

[0089] Please combine Fig. 9 , which is Figure 3 Schematic diagram of the relative position of the laser focus and the change in the size of the fluorescent spot. It can be seen that when the laser focus is completely in the substrate, the fluorescent polymer does not produce a fluorescent effect, so there is no fluorescent spot in the spot image. When the laser focus moves from the substrate to the fluorescent polymer until it contacts the fluorescent polymer, the fluorescent polymer produces a fluorescent effect, and a fluorescent spot begins to appear in the spot image. When the laser focus continues to move into the fluorescent polymer until the center of the laser focus is just located at the interface between the substrate and the fluorescent polymer, the fluorescence effect produced by the fluorescent polymer reaches its maximum, and the equivalent diameter of the spot in the spot image also reaches its maximum. The laser focus continues to move until it is completely in the fluorescent polymer, and the size of the spot in the spot image no longer changes.

[0090] S222: Determine whether the size of the light spot increases, and make the following decision: If the light spot gradually decreases, move the base in the opposite direction to increase the size of the light spot in the light spot image. If the light spot gradually increases, control the base to continue moving in the original direction until the size of the light spot remains unchanged. If the light spot remains unchanged, the equivalent diameter of the light spot reaches the maximum, and the minimum circumscribed circle of the light spot is obtained, and the diameter of the minimum circumscribed circle is the reference value.

[0091] According to the change of the fluorescence effect generated by the light spot in the substrate and the fluorescent polymer, the laser focus can be moved to the interface between the substrate and the fluorescent polymer by moving the substrate. After the light spot size no longer changes, take any light spot image, and the smallest circle outside the light spot is the equivalent diameter of the light spot. In this embodiment, the maximum equivalent diameter of the light spot is recorded as the reference value.

[0092] S23: Calculate the ideal value of the equivalent diameter of the light spot based on the physical properties of the fluorescent polymer and the benchmark value.

[0093] Please combine Fig.10 , which is Figure 3 Schematic diagram of the size of the fluorescent spot when the laser focus is at different positions. Fig.10 .a is a schematic diagram of the spot image when the laser focus is located in the substrate; Fig.10.b is a schematic diagram of the spot image when the laser focus begins to contact the fluorescent polymer; Fig.10 .c is a schematic diagram of the spot image when the laser focus is located at the interface between the substrate and the fluorescent polymer; Fig.10 .d is a schematic diagram of the spot image when the laser focus is at the ideal position. Since the physical properties of fluorescent polymers vary, the ideal processing position actually selected is not exactly on the interface. Taking photoresist as an example, when the equivalent diameter of the fluorescent spot in the spot image reaches 2 / 3 of the reference value, the laser focus is exactly at the ideal processing position. That is, 2 / 3 of the reference value is the ideal value of the equivalent diameter of the spot.

[0094] S24: Adjust the height of the substrate until the equivalent diameter of the light spot in the light spot image is equal to the ideal value.

[0095] Since the size of the laser focus is tiny, only 0.5-2μm, it is difficult to focus accurately even when observing under an objective lens. Through the fluorescence effect of fluorescent polymers, the laser focus is converted into image processing, which effectively improves the accuracy of focusing. At the same time, the efficiency of image recognition is higher than that of human eye observation, which can also avoid eye injuries and improve the safety of focusing.

[0096] S3: Control the substrate to move to the next processing point according to the preset moving path. Determine whether the equivalent diameter of the spot in the spot image is equal to the ideal value, and make the following decision:

[0097] (1) If yes, laser processing is directly performed at this position. When the equivalent diameter of the spot in the spot image is equal to the ideal value, focusing is completed at the processing point, and laser processing can be directly performed according to the processing strategy.

[0098] (2) Otherwise, focus is performed on the processing point, and laser processing is performed on the processing point after focusing is completed. During the laser processing, after laser processing is completed at any processing point, the substrate only moves in the horizontal direction. Since there is an angle between the tilt direction of the substrate and the horizontal plane, and the height of the substrate changes after processing is completed, it is necessary to continue focusing to confirm the actual processing position.

[0099] Please combine Fig.11 , which is Figure 3 Schematic diagram of the movement direction of the substrate in FIG. In this embodiment, the movement of the substrate is three-dimensional, with the initial processing point as the origin, the vertical direction as the Z axis, any horizontal direction as the X axis, and the other horizontal direction perpendicular to the X axis as the Y axis. Then the movement path of the substrate between the processing points only includes the movement of the substrate on the X axis and the Y axis. The focusing process only includes the movement of the substrate on the Z axis.

[0100] S4: Determine whether the processing is completed. If the processing is not completed, repeat S3 until the processing is completed. If the processing is completed, develop the processed micro-nano structure to obtain a finished micro-nano structure.

[0101] Since the designed structure is a three-dimensional micro-nano structure, the fluorescent polymer needs to be processed at multiple points on the substrate. Whether the processing is completed can be judged based on the designed structure and the completed processing position. After the micro-nano structure is processed, it is necessary to develop the micro-nano structure to remove the part of the micro-nano structure that exceeds the designed structure to obtain a finished micro-nano structure.

[0102] The two-photon automatic processing method for non-flat substrates provided in this embodiment adopts point-by-point focusing and fluorescence focusing methods. By converting the focusing of the laser focus into fluorescence image recognition, whether the focusing is completed is confirmed according to the equivalent diameter of the light spot, thereby effectively improving the focusing efficiency and focusing accuracy. In addition, by automatically focusing each processing point, the problem that manual focusing operation is complicated, time-consuming and has large errors during the processing of non-flat substrates using lasers is solved. In order to realize two-photon automatic processing for non-flat substrates, this embodiment also provides a two-photon automatic processing system for non-flat substrates. The processing system includes an imaging module, an image processing module, a decision module and a displacement control module.

[0103] The imaging module is used to collect the spot image containing the fluorescent polymer and its scattered fluorescence in real time. The fluorescent polymer produces a fluorescent effect under the irradiation of the laser focus. By real-time shooting of the substrate and the fluorescent polymer, an image containing the fluorescent polymer and its scattered fluorescence is obtained. The spot image collected by the imaging module is transmitted to the image processing module.

[0104] The image processing module is used to preprocess the spot image and calculate the equivalent diameter of the spot in the spot image. The preprocessing of the spot image includes normalization and filtering. Normalization can convert each spot image into the same form, maintain the same standard during multiple processing, and improve the processing accuracy. Filtering can suppress the noise of the image while retaining the image detail features, thereby improving the accuracy of image processing. The equivalent diameter of the spot can be obtained through an image recognition model. For example, the color threshold method is first used to convert the color space of the image into the HSV color space, and then the spot is extracted according to the color threshold. Subsequently, the graphic recognition model is used to add the minimum circumscribed circle to the spot, and the diameter of the circumscribed circle is obtained as the equivalent diameter of the spot.

[0105] The decision module is used to: 1. determine whether the equivalent diameter of the light spot is the maximum value, and if so, record the maximum value of the equivalent diameter as the reference value.

[0106] The relationship between the equivalent diameter of the fluorescent spot and the change of the laser focus position is: when the laser focus is completely in the substrate, the fluorescent polymer does not produce a fluorescent effect, so there is no fluorescent spot in the spot image. When the laser focus moves from the substrate to the fluorescent polymer until it contacts the fluorescent polymer, the fluorescent polymer produces a fluorescent effect, and a fluorescent spot begins to appear in the spot image. When the laser focus continues to move into the fluorescent polymer until the center of the laser focus is just located at the interface between the substrate and the fluorescent polymer, the fluorescent effect produced by the fluorescent polymer reaches the maximum, and the equivalent diameter of the spot in the spot image also reaches the maximum. The laser focus continues to move until it is completely in the fluorescent polymer, and the size of the spot in the spot image no longer changes.

[0107] It can be seen that when the equivalent diameter of the fluorescent spot reaches the maximum, the laser focus is just located at the interface between the substrate and the fluorescent polymer. The interface between the substrate and the fluorescent polymer is the reference surface for processing.

[0108] 2. Determine whether the equivalent diameter of the light spot is the ideal value. If so, confirm that the focus is completed.

[0109] Since the physical properties of fluorescent polymers vary, the ideal processing position actually selected is not exactly on the interface. Taking photoresist as an example, when the equivalent diameter of the fluorescent spot in the spot image reaches 2 / 3 of the reference value, the laser focus is exactly at the ideal processing position. That is, 2 / 3 of the reference value is the ideal value of the spot equivalent diameter.

[0110] The displacement control module is used to: Ⅰ. Output displacement signals according to the preset moving path, and then control the motion stage to drive the substrate to move horizontally. During the laser processing, multiple processing points need to be set, and laser processing is performed at each processing point. In order to ensure that the processed three-dimensional micro-nano structure is as consistent as possible with the designed structure, the processing point is positioned on the substrate by horizontal movement.

[0111] Ⅱ. Output displacement signals according to the preset processing strategy, and then control the motion stage to drive the substrate to move three-dimensionally. At any processing point, the movement path of the laser focus is different depending on the design structure. The processing of three-dimensional micro-nano structures requires movement in at least three degrees of freedom.

[0112] III. Output lifting signals during focusing to control the motion stage to drive the substrate to lift. For any processing point, after finding the horizontal position of the processing point, it is only necessary to lift the substrate to complete the focusing. The focusing method includes: obtaining a spot image of the fluorescent polymer and its scattered fluorescence, and adjusting the height of the substrate until the equivalent diameter of the spot in the spot image is equal to the ideal value.

[0113] For any processing point, the focusing method may also include: adjusting the height of the substrate so that the laser focus is just located on the interface between the substrate and the fluorescent polymer, that is, the equivalent diameter of the light spot in the light spot image just increases to the reference value or just starts to decrease from the reference value, and moves up or down a preset distance so that the equivalent diameter of the light spot in the light spot image is equal to the ideal value. During the focusing process, the upward or downward movement of the substrate can be determined according to the relative position of the substrate and the fluorescent polymer. If the substrate is located below the fluorescent polymer, when the equivalent diameter of the light spot in the light spot image is equal to the reference value, the substrate is moved up to move the laser focus toward the substrate, and the equivalent diameter of the light spot in the light spot image gradually decreases, and the distance from the reference plane to the ideal processing surface is recorded. Then, each subsequent focusing only requires moving the substrate down a corresponding distance after the laser focus reaches the reference plane.

[0114] Please combine Fig.12 , which adopts Figure 3 Schematic diagram of laser path of two-photon automatic processing equipment for non-flat substrates in two-photon automatic processing method for non-flat substrates. This embodiment also optimizes the existing two-photon direct writing processing equipment according to the two-photon automatic processing method and system for non-flat substrates to obtain a two-photon automatic processing equipment for non-flat substrates. The processing equipment includes a laser, a motion stage, a substrate, an optical path regulator, an objective lens, an imaging device and a controller.

[0115] The laser is used to emit laser. This embodiment uses a femtosecond laser. The femtosecond laser is a ChameleonVision-S laser produced by Coherent, with an output wavelength adjustment range of 690nm to 1050nm, a laser pulse width of 75fs, a repetition frequency of 80MHz, and an average output power of 2.5W. The laser wavelength used in laser two-photon processing is 800nm. Of course, in other embodiments, the laser can also be a pulsed laser or a continuous laser, etc., as long as it can emit the laser required for laser processing.

[0116] The substrate is used to carry the fluorescent polymer so that the fluorescent polymer is located on the laser path, and the fluorescent polymer is irradiated with the laser to produce a fluorescent effect. In the present embodiment, PDMS is used as a flexible non-flat substrate, and the fluorescent polymer is dripped on the flexible substrate. Under the action of the laser, the PDMS produces a light spot that is significantly different from the fluorescent polymer. Of course, in other embodiments, the substrate can also be made of transparent materials such as plastic sheets so that the laser can pass through the substrate and irradiate the fluorescent polymer. In the present embodiment, the fluorescent polymer uses a photoresist (SZ2080), and the photoresist has a fluorescent effect. Before processing, the photoresist is placed on a glass slide and baked in a hot oven at 60° for 15 minutes. Of course, in other embodiments, the fluorescent polymer can also use other photosensitive materials with a fluorescent effect or doped with a fluorescent effect substance such as a photosensitive resin, a photosensitive hydrogel, etc., as long as it is three-dimensionally formed into a designed structure after laser processing and development. Of course, when other fluorescent polymers are selected, the ratio of the ideal value of the equivalent diameter of the light spot in the light spot image to the reference value also changes accordingly, and the ratio is set according to the physical properties of the fluorescent polymer used.

[0117] The motion stage is fixedly connected to the substrate and is used to drive the substrate to move. The substrate can be fixedly connected to the motion stage by methods such as magnetic attraction to ensure that the substrate will not deviate when the motion stage drives the substrate to move. In this embodiment, the PI-E545 nano motion stage is used, which can drive the substrate to move in three directions of x, y, and z. The PI-E545 nano motion stage is electrically connected to the controller, and its movement is controlled by the controller. During the laser processing process, the substrate is deflected around the x-axis and y-axis at different angles, so that the laser focus can be scanned in the xy plane, and the height of the substrate can be adjusted directly by lifting and moving in the z-axis direction. Of course, in other embodiments, other micrometer-level or nanometer-level motion stages can also be used, as long as the substrate can be accurately moved in three-dimensional space.

[0118] The optical path regulator is set on the emission path of the laser to adjust the intensity and direction of the laser so that the laser can be used for processing or focusing respectively. The optical path regulator includes an optical gate and a pre-regulator spectroscope. The pre-regulator is set on the laser emission path of the laser to adjust the energy and phase of the laser.

[0119] The pre-regulator includes a Glan Taylor prism, a half-wave plate, a beam expander, a reflector and an attenuation plate arranged in sequence along the laser emission path. The Glan Taylor prism is used to control the energy of the laser beam. The Glan Taylor prism is arranged on the emission path of the laser to convert the laser into polarized light. The Glan Taylor prism is a birefringent polarizing device made of natural calcite crystals, and the main component is the rhombic hexahedral crystal of CaCO3. A beam of linearly polarized light (e-light) can be obtained by inputting an unbiased collimated laser beam into the Glan Taylor prism. Compared with other polarizing plates, the Glan Taylor prism has higher transmittance and polarization purity. The half-wave plate is used to adjust the phase of the laser beam. The half-wave plate is a birefringent crystal with a certain thickness. When the normally incident light is transmitted, the phase difference between the ordinary light (o-light) and the linearly polarized light (e-light) is equal to π or an odd multiple of π. The beam expander is used to increase the diameter of the laser beam. The beam expander is a lens component that can change the diameter and divergence angle of the laser beam. The laser emitted from the laser has a certain divergence angle. The laser beam is adjusted to a collimated (parallel) laser beam by adjusting the beam expander. The reflector is used to adjust the emission direction of the laser beam. The attenuation sheet is used to adjust the energy of the laser beam. By using the absorption characteristics of the material to light, the material is made into a sheet and placed on the optical path adjustment component to attenuate the light intensity. This sheet-like component is called an optical attenuation sheet. The amount of light passing through the attenuation sheet is related to the type of material and the thickness of the material.

[0120] The optical shutter is set between the laser and the pre-regulator to control the on and off of the laser.

[0121] The beam splitter is arranged on the laser emission path of the pre-regulator, and is used to reflect the processed laser and transmit the imaging light, and respectively make the reflected laser incident on the objective lens, and the transmitted light enter the imaging device. In the present embodiment, the beam splitter is a dichroic mirror, which has the characteristics of reflecting infrared light with a wavelength of 750-850nm and transmitting visible light with a wavelength of 400-700nm. The laser with a wavelength of 800nm ​​emitted by the laser is reflected by the reflector and vertically incident on the objective lens, and other visible light is directly transmitted to avoid affecting the processing or focusing process. In addition, the wavelength of the fluorescence emitted by the fluorescent polymer is generally between 450-600nm, and it will also be directly transmitted from the beam splitter and captured by the camera, which can not only improve the clarity of the fluorescence imaging, but also avoid interference of the fluorescence on the laser processing.

[0122] Of course, in other embodiments, the optical path adjustment component can also be replaced by a light-guiding element such as an optical fiber, as long as the laser can be converted into a collimated laser beam and vertically incident on the objective lens.

[0123] The objective lens is arranged on the laser emission path of the optical path regulator to focus the laser. In this embodiment, the magnification of the objective lens is 50 times, and the numerical aperture of the objective lens is 0.8. Of course, in other embodiments, the magnification and numerical aperture of the objective lens can be larger or smaller.

[0124] The imaging device is arranged on the fluorescence path scattered by the fluorescent polymer, and is used to collect the spot image containing the fluorescent polymer and its scattered fluorescence in real time. The imaging device is also used to transmit the collected spot image to the controller. In this embodiment, the imaging device is a CCD camera. The CCD camera has the characteristics of small size, light weight, unaffected by magnetic fields and anti-vibration and impact. The image collected by the CCD camera has the characteristics of high clarity and easy transmission. Of course, in other embodiments, the imaging device can also be replaced by a photoelectric conversion element such as a photodiode, a phototransistor, etc., as long as the light signal emitted by the substrate and the fluorescent polymer can be converted into an image or an electrical signal.

[0125] The controller is used to: 1. Control the motion stage to adjust the horizontal position of the substrate so that the horizontal position of the laser focus is located within the initial processing area of ​​the substrate. During the laser processing process, the controller first generates a scanning strategy based on the designed micro-nano structure. The scanning strategy includes a horizontal movement path formed based on multiple processing points and a processing strategy generated at each processing point. Subsequently, the substrate is moved so that the horizontal position of the laser focus is located within the preset initial processing area, thereby avoiding the loss of the structure caused by the processed micro-nano structure exceeding the surface of the substrate.

[0126] Second, focus the laser emitted by the laser so that the substrate is located at the ideal initial processing position, and perform laser processing at the initial processing position according to the corresponding processing strategy. After the laser focus is located in the initial processing area, the substrate needs to be moved to the ideal processing position to avoid partial or complete loss of the processing structure. The focusing method includes: obtaining a spot image of the fluorescent polymer and its scattered fluorescence, and adjusting the height of the substrate until the equivalent diameter of the spot in the spot image is equal to the ideal value.

[0127] 3. According to the preset moving path, the motion stage is controlled to drive the substrate to move, and then the corresponding laser processing is completed at each processing point. Laser focusing is performed at each processing point to reduce or eliminate the influence of substrate non-flatness on laser processing and improve the accuracy of laser processing.

[0128] Fourth, determine whether the equivalent diameter of the spot in the spot image is equal to the ideal value. If it is, laser processing is performed directly at this position. Otherwise, focus is performed at the processing point, and laser processing is performed at the processing point after focusing. Since the designed structure is a three-dimensional micro-nano structure, the fluorescent polymer needs to be processed at multiple points on the substrate. Whether the processing is completed can be determined based on the designed structure and the completed processing position. After the micro-nano structure processing is completed, the micro-nano structure needs to be developed to remove the part of the micro-nano structure that exceeds the designed structure to obtain a finished micro-nano structure.

[0129] The two-photon automatic processing equipment for non-flat substrates provided in this embodiment converts the focusing of the laser focus into fluorescent image recognition, and confirms whether the focusing is completed according to the equivalent diameter of the light spot, thereby effectively improving the focusing efficiency and focusing accuracy. In addition, by automatically focusing each processing point, the problem that manual focusing operation is complicated, time-consuming and has large errors during the processing of laser on non-flat substrates is solved.

[0130] Experimental verification

[0131] Experiment 1: Observe the changing relationship between the processed micro-nano structure and the designed structure when the laser focus is at different positions.

[0132] A substrate with an inclined surface is used and fixedly connected to the motion stage. The wavelength of the laser emitted by the laser is adjusted to 800nm ​​through the optical path regulator, and the array processing is performed in a horizontal direction, keeping all processing points on the same horizontal plane, and the micro-column structure color is obtained. Fig.13 Then, while keeping the substrate and laser wavelength unchanged, each processing point is focused, and the obtained microcolumn structural color is shown in Fig.14 shown.

[0133] See also Fig.13 and Fig.14 , Fig.13 The structural color and micropillar array images are caused by the inconsistency between the relative height of the laser focus and the substrate surface; Fig.14 The fluorescence color and micro-pillar array diagram after using autofocus. It can be seen that when each processing point is not focused, although the laser focus is maintained on the same horizontal plane, the relative height between the laser focus and the substrate changes due to the tilt of the substrate surface. On a processing path with a total length of 50μm, the height of the micro-pillar processed at the first processing point differs from the height of the micro-pillar processed at the last processing point (the sixth processing point) by 1.5μm. The fluorescence colors scattered by each micro-pillar are green, blue, red, orange, yellow and yellow in sequence.

[0134] According to the experimental results, the non-flat substrate will cause the micro-pillar array of the same height to be processed to have inconsistent height. Among them, the reason for the micro-pillars of different structural colors is that the non-flat substrate leads to inconsistent processing height, which in turn leads to different heights of the processed microstructures, thus causing changes in structural colors. The reason for the different micro-pillar heights is that the relative position of the laser focus and the substrate surface is different, so the actual processing structure is inconsistent with the designed structure parameters.

[0135] Fig.14 It can be seen that the use of autofocus can make the height of the processed microcolumns consistent, and the structural color of each microcolumn is also red. In this experiment, the non-planarity error or inclination of the experimental platform processing substrate is between 1:50 and 1:25, which has a relatively large impact on the micro-nano structure. Therefore, this method is used to correct the impact of the non-planar substrate. When the initial position is positioned at the ideal processing position, the size of the fluorescent spot at this time is recorded, and the size of the fluorescent spot generated by the subsequent processing array is compared with the initial position. When inconsistencies occur, the rotating mirror stage is controlled to move until the current fluorescent spot size is the same as the fluorescent spot size at the initial position. After using autofocus on the non-flat substrate through the two-photon direct writing process based on the fluorescence effect, the processed microcolumn array is highly consistent, which can reduce the impact of changes in the non-flat substrate on the processed structure.

[0136] Experiment 2: Processing micro-nano structures on patterned substrates using the autofocus method and without the autofocus method.

[0137] See also Fig.15 , which is a comparison diagram of the experiments of processing micro-nano structures at different positions on the patterned substrate. Fig.15 a is a schematic diagram of the structure of the patterned substrate; Fig.15 b is a diagram showing the effect of processing a micro-nano array on a patterned substrate without using an automatic processing method; Fig.15 c is the effect diagram of adjusting the focus position and processing the micro-nano array on the patterned substrate. Fig.15 As shown in a, the patterned substrate can be obtained using a photolithography method. The specific process is to spin-coat a 50-micron thick SU-8 photoresist on a glass slide, and use a photolithography machine (model: ABM6350) to expose the patterned photoresist. After exposure, the developer is used to remove the excess part, and the photoresist structure forms a groove structure of the designed width on the surface of the glass slide. In this experiment, the groove depth is 50 microns and the width is 80 to 150 microns.

[0138] SZ2080 photoresist was dripped onto the patterned substrate and pre-baked at 100 degrees for 30 minutes. The substrate was fixedly connected to the motion stage, and the laser wavelength emitted by the femtosecond laser was adjusted to 800 nm through the optical path regulator, and then the array processing was carried out.

[0139] from Fig.15 b and Fig.15 As can be seen in c, when each processing point is not automatically processed, although the laser focus is kept on the same horizontal plane, the processed substrate is a groove structure. In the transition area between the bottom of the groove and the sidewall, due to the change in the height of the substrate, the height of the processed micro-pillar is significantly different from the height of the micro-pillar at the bottom of the groove. This causes some of the processed micro-pillars to collapse and deform, and the processing effect is not good. When using the focus adjustment method, it can be seen that the height of the processed micro-pillar array is consistent, there is no collapse and deformation, and the overall processing effect is good.

[0140] Therefore, the automatic processing method of the present invention can correct the influence of the non-planar substrate on the processing, and realize a complete three-dimensional micro-nano structure array on the non-planar substrate.

[0141] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0142] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A two-photon automatic processing method for non-flat substrates, characterized in that: It includes the following process: S1: adjusting the horizontal position of the substrate so that the horizontal position of the laser focus is located within the initial processing area of ​​the substrate; the initial processing area means that when any point in the area is selected as the initial processing point, the horizontal area where the design structure is located is located on the substrate; S2: focusing the laser so that the substrate is located at an ideal initial processing position, and laser processing is performed at the initial processing position according to a corresponding processing strategy; wherein the focusing method is as follows: S21: taking the fluorescent polymer as the object of framing, collecting the spot image of the scattered fluorescence of the fluorescent polymer in real time; S22: adjusting the height of the substrate, when the equivalent diameter of the light spot in the light spot image reaches a maximum value, calculating the maximum equivalent diameter of the light spot as a reference value; S23: Calculate the ideal value of the equivalent diameter of the light spot according to the physical properties of the fluorescent polymer and the benchmark value; S24: adjusting the height of the substrate until the equivalent diameter of the light spot in the light spot image is equal to the ideal value; S3: Control the substrate to move to the next processing point according to the preset moving path; determine whether the equivalent diameter of the light spot in the light spot image is equal to the ideal value, and make the following decisions: (1) If yes, laser processing is performed directly at that position; (2) otherwise, focusing is performed at the processing point, and laser processing is performed at the processing point after focusing is completed; S4: judging whether the processing is completed. If the processing is not completed, repeating S3 until the processing is completed; if the processing is completed, developing the processed micro-nano structure to obtain a finished micro-nano structure; In S1, the initial processing area is calculated according to the horizontal area covered by the substrate and the horizontal area covered by the scanning strategy, and the specific method is as follows: a. The shape of the base p j , the shape of the laser focus l , horizontal area p covered by the machining strategy p and the horizontal area p covered by the scanning strategy s Mapping on the same plane; p l and p p Concentric setting, and at p j Inner edge p p With p j The tangent path moves one circle; l With p j The area enclosed by p j Remove from the middle and get the intermediate shape p m ; b. for p m Scale until the scaled figure is just circumscribed on p s On; let p m is an n-gon, circumscribed at p s The graph on is p ms , then p ms The n corners of the m At each corner of the joint, each time the joint is made, the other n-2 sides that are not adjacent to the joint corner are extended; multiple extension lines will s Divide into multiple sub-regions; include p m The sub-area of ​​each corner is used as the initial processing area.

2. The two-photon automatic processing method for a non-flat substrate according to claim 1, characterized in that: In S1, the method for determining whether the laser focus is within the initial processing area is as follows: S11: taking the substrate as a framing object, collecting a substrate image including the laser focus; S12: preprocessing the substrate image to retain the outer contour of the substrate and the outer contour of the laser focus; S13: adding the outline of the initial processing area to the outer contour of the substrate; S14: Observe whether the outer contour of the laser focus is completely within the initial processing area. If yes, confirm that the laser focus is within the initial processing area; otherwise, move the substrate until the outer contour of the laser focus is completely within the initial processing area.

3. The two-photon automatic processing method for non-flat substrates according to claim 1, characterized in that: In S22, the method for obtaining the reference value is as follows: S221: Observe whether there is a light spot in the initial light spot image, and make the following decisions: if there is no light spot, lift the substrate until a light spot appears in the light spot image; if there is a light spot, control the substrate to move up or down, and observe the change in the size of the light spot; S222: Determine whether the size of the light spot increases, and make the following decisions: if the light spot gradually becomes smaller, move the substrate in the opposite direction to increase the size of the light spot in the light spot image; if the light spot gradually becomes larger, control the substrate to continue moving in the original direction until the size of the light spot remains unchanged; if the light spot remains unchanged, the equivalent diameter of the light spot reaches the maximum, and the minimum circumscribed circle of the light spot is obtained, and the diameter of the minimum circumscribed circle is the reference value.

4. The two-photon automatic processing method for non-flat substrates according to claim 1, characterized in that: In S3, the movement of the substrate is three-dimensional, with the initial processing point as the origin, the vertical direction as the Z axis, any horizontal direction as the X axis, and the other horizontal direction perpendicular to the X axis as the Y axis; the movement path only includes the movement of the substrate on the X axis and the Y axis; the focusing process only includes the movement of the substrate on the Z axis.

5. A two-photon automatic processing system for a non-flat substrate, which adopts the two-photon automatic processing method for a non-flat substrate as claimed in any one of claims 1 to 4, characterized in that: It includes: An imaging module, which is used to collect a spot image containing a fluorescent polymer and its scattered fluorescence in real time; An image processing module, which is used to pre-process the light spot image and calculate the equivalent diameter of the light spot in the light spot image; The decision module is used to:

1. determine whether the equivalent diameter of the light spot is a maximum value, and if so, record the maximum value of the equivalent diameter as a reference value; 2. determine whether the equivalent diameter of the light spot is an ideal value, and if so, confirm that the focus is completed; The displacement control module is used to: Ⅰ. output a displacement signal according to a preset moving path, thereby controlling the motion stage to drive the substrate to move horizontally; Ⅱ. output a displacement signal according to a preset processing strategy, thereby controlling the motion stage to drive the substrate to move three-dimensionally; Ⅲ. output a lifting signal during focusing, thereby controlling the motion stage to drive the substrate to lift.

6. A two-photon automatic processing device for a non-flat substrate, which is used to process a fluorescent polymer to be processed into a corresponding three-dimensional micro-nano structure according to a design structure; it adopts the two-photon automatic processing method for a non-flat substrate as described in any one of claims 1 to 4; the processing device comprises a laser, a motion stage and a substrate; the laser is used to emit laser light; the substrate is used to carry the fluorescent polymer so that the fluorescent polymer is located on the laser path and the fluorescent polymer produces a fluorescent effect when irradiated by the laser; the motion stage is fixedly connected to the substrate and is used to drive the substrate to move; it is characterized in that The processing equipment also includes: An optical path regulator, which is arranged on the emission path of the laser and is used to adjust the intensity and direction of the laser so that the laser can be used for processing or focusing respectively; An objective lens, which is arranged on the laser emission path of the optical path regulator and is used to focus the laser; An imaging device, which is arranged on the fluorescence path scattered by the fluorescent polymer and is used to collect a spot image containing the fluorescent polymer and its scattered fluorescence in real time; and The controller is used to:

1. control the motion stage to adjust the horizontal position of the substrate so that the horizontal position of the laser focus is located in the initial processing area of ​​the substrate; 2. focus the laser emitted by the laser so that the substrate is located at an ideal initial processing position, and perform laser processing at the initial processing position according to the corresponding processing strategy; 3. control the motion stage to drive the movement of the substrate according to a preset moving path, and then complete the corresponding laser processing at each processing point; 4. determine whether the equivalent diameter of the spot in the spot image is equal to the ideal value, and if so, directly perform laser processing at this position; otherwise, focus at the processing point, and perform laser processing at the processing point after completing the focusing.

7. The two-photon automatic processing equipment for non-flat substrates according to claim 6, characterized in that: The optical path regulator includes a light gate, a pre-regulator and a spectroscope; the pre-regulator is arranged on the laser emission path of the laser and is used to adjust the energy and phase of the laser; the light gate is arranged between the laser and the pre-regulator and is used to control the on and off of the laser; the spectroscope is arranged on the laser emission path of the pre-regulator and is used to reflect the incident laser used for micro-nano processing into the objective lens, and transmit the image and fluorescence signal of the processing site into the imaging device through the spectroscope.

8. The two-photon automatic processing equipment for non-flat substrates according to claim 7, characterized in that: The pre-regulator includes a Glan Taylor prism, a half-wave plate, a beam expander, a reflector and an attenuation plate which are arranged in sequence along the laser emission path; the Glan Taylor prism is used to control the energy of the laser beam; the half-wave plate is used to adjust the phase of the laser beam; the beam expander is used to adjust the diameter of the laser beam; the reflector is used to adjust the emission direction of the laser beam; and the attenuation plate is used to adjust the energy of the laser beam.

9. The two-photon automatic processing equipment for non-flat substrates according to claim 6, characterized in that: The laser is a femtosecond laser; the imaging device is a CCD camera; and the motion stage is a three-dimensional micro-nano motion stage.

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