A laser micro-nano machining device and method based on an acousto-optic deflector and a rotating mirror

Abstract

The application relates to the field of laser micro-nano processing, in particular to a laser micro-nano processing device based on an acousto-optic deflector and a rotating mirror and a use method thereof, which comprises a pulse laser, a mirror group, an acousto-optic deflection module, a signal control unit, a beam splitting module, a rotating mirror and a flat-field focusing lens arranged in sequence; the acousto-optic deflection module comprises a first acousto-optic deflector and a second acousto-optic deflector, the first acousto-optic deflector and the second acousto-optic deflector are orthogonally arranged, the first acousto-optic deflector is arranged in parallel with the rotating shaft of the rotating mirror, the second acousto-optic deflector is arranged in perpendicular to the rotating shaft of the rotating mirror, through the arrangement of the two orthogonally arranged acousto-optic deflectors, the laser beam can be flexibly controlled to be deflected to any position in a rectangular scanning area, and in combination with the polygon rotating mirror, the polygon rotating mirror can be rotated only once along a processing track, the acousto-optic deflector can compensate and fill a processing pattern, and the technical effect that any shape can be realized is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser micro-nano processing, in particular, to a laser micro-nano processing device based on an acousto-optic deflector and a rotating mirror and a use method thereof. BACKGROUND

[0002] Laser micro-nano processing technology can realize shape and property control manufacturing in micron to nanometer scale, and is not limited to simple cutting or punching, but also can be used for material surface texturing, super-hydrophobicity preparation, microstructure processing, etc., thereby having wide application in microelectronic devices, semiconductor manufacturing, biomedical, etc.

[0003] With the continuous improvement of laser repetition frequency, higher requirements are put forward for the processing speed and precision of laser micro-nano processing, and the control ability of laser beam deflection directly determines the precision and quality of processing. At present, mechanical scanning controllers are mainly used, such as galvanometer mirrors, polygon rotating mirrors, etc. However, mechanical deflection devices have mechanical inertia in trajectory transformation, which affects the processing efficiency and effect. For example, two-dimensional deflection scanning can be realized by using a galvanometer mirror, but due to the mechanical inertia, there will be acceleration and deceleration process when the trajectory is switched, resulting in low processing efficiency and energy utilization. Secondly, the scanning precision of the galvanometer mirror is low, and it is difficult to complete the processing of fine structure patterns. At the same time, the deflection angular velocity of the galvanometer mirror is slow, which is difficult to adapt to the requirements of today's high repetition frequency lasers, resulting in serious heat accumulation. Compared with the galvanometer mirror, the polygon rotating mirror breaks through the short board of the changing speed of the rotating mirror back and forth swing in scanning speed through high-speed rotation, and has faster scanning speed (100 times faster than the galvanometer mirror), more stable, and higher damage threshold, but faces the problems of uncontrollable laser pulse and trajectory (only one-dimensional line scanning can be performed), and the application scene is limited. The acousto-optic deflector utilizes the acousto-optic Bragg diffraction effect, realizes high-speed deflection of incident laser by efficient regulation of the acoustic field, has the characteristics of no mechanical vibration, short response time (in the order of us), high deflection angular velocity (up to 1000 rad / s), high scanning precision (<0.1 urad), and controllable laser beam pulse by pulse, but the scanning range is narrow, and it needs to be cooperated with other components for processing.

[0004] In summary, the traditional laser micro-nano processing based on mechanical deflection mainly has the problems of mechanical inertia, low processing efficiency and energy utilization, low processing precision, and slow deflection speed. The cooperation of acousto-optic deflector and polygon rotating mirror can greatly improve the processing efficiency and precision, and meet the needs of high-speed, high-efficiency and high-quality processing.

[0005] The prior art CN112705841A discloses a kind of ultrafast laser high-speed micro-nano machining system based on polygon scanning rotating mirror, scanning galvanometer and polygon rotating mirror are inertial components, cannot accurately process the pattern with very dramatic change of curvature radius, also cannot realize the pulse-by-pulse control of laser pulse, and there is no parallel processing function, and the processing efficiency is slow;The prior art CN117754121A discloses a kind of multi-rotating mirror laser scanning machining system and method, although the same processing path can be realized in the way of multiple rotating mirrors in series, the processing path is separate due to the volume of galvanometer, cannot realize the pattern of processing a certain width pattern, and can only realize line scanning effect, and cannot process other patterns. SUMMARY

[0006] In view of the defects of the related art, the purpose of the present application is to provide a kind of laser micro-nano machining device based on acousto-optic deflector and rotating mirror and its use method, to solve the technical problems of traditional mechanical deflector-based laser micro-nano machining, such as mechanical inertia, low processing efficiency and energy utilization, low processing precision and slow deflection speed.

[0007] According to the first aspect of the present application, a kind of laser micro-nano machining device based on acousto-optic deflector and rotating mirror is provided, including pulse laser, reflecting mirror group, acousto-optic deflection module, signal control unit, beam splitting module, rotating mirror, flat-field focusing lens;

[0008] The pulse laser is used to provide pulse laser;

[0009] The reflecting mirror group is used to reflect the laser output by the pulse laser into the acousto-optic deflection module, and keep the laser incident to the acousto-optic deflection module at Bragg angle, change the deflection position of the laser;

[0010] The signal control unit controls the acousto-optic deflection module, for inputting the frequency signal set in the acousto-optic deflection module;

[0011] The beam splitting module is used to divide the laser into mutually parallel beams, to realize light splitting;

[0012] The rotating mirror is used to reflect the mutually parallel beams to the flat-field focusing lens, and the flat-field focusing lens is used to converge the beams at the focus point, and the focus point is used to place the component to be processed.

[0013] Preferably, the acousto-optic deflection module satisfies: (i) the acousto-optic deflection module includes a first acousto-optic deflector and a second acousto-optic deflector, the first acousto-optic deflector and the second acousto-optic deflector are placed orthogonally, the first acousto-optic deflector is placed parallel to the rotation axis of the rotating mirror, and the second acousto-optic deflector is placed perpendicular to the rotation axis of the rotating mirror;

[0014] Or (ii) the acousto-optic deflection module comprises a first acousto-optic deflector, which is placed parallel to the rotation axis of the rotating mirror.

[0015] Preferably, the first acousto-optic deflector and the second acousto-optic deflector each comprise a driving signal source, an ultrasonic transducer, and an acousto-optic medium; the acousto-optic medium is connected to the ultrasonic transducer, the electrode on the ultrasonic transducer is connected to the driving signal source, and the signal control unit is connected to the driving signal source.

[0016] Preferably, the material of the acousto-optic medium is selected from quartz, tellurium oxide, and germanium.

[0017] Preferably, the beam splitting module is selected from a flat plate beam splitter, a cubic beam splitter, and a diffractive optical element.

[0018] Preferably, the rotating mirror is a regular m-polygonal prism, and m is 3-16.

[0019] Preferably, the laser micro-nano processing device further comprises a beam expanding and collimating device, a displacement table, a camera, and a central control unit.

[0020] The beam expanding and collimating device is arranged between the pulsed laser and the mirror group, and is used for expanding and collimating the laser output by the pulsed laser and then emitting the laser.

[0021] The processing component is fixedly arranged on the displacement table and can move with the displacement table.

[0022] The camera is used for monitoring the processing condition of the processing component in real time and feeding back in real time.

[0023] The central control unit is connected to the rotating mirror, the signal synchronization control unit, the camera, and the displacement table, respectively.

[0024] Preferably, the laser micro-nano processing device further comprises a motor connected to the rotating mirror.

[0025] According to another aspect of the present application, a laser micro-nano processing method based on an acousto-optic deflector and a rotating mirror is provided, and the specific steps are as follows:

[0026] (1) A pulsed laser provides pulsed laser, which is reflected by a mirror group and then incident on the acousto-optic deflection module at a Bragg angle; the acousto-optic deflection module is controlled by a frequency signal emitted by a signal control unit to change the deflection angle of the light beam emitted from the acousto-optic deflection module.

[0027] (2) The laser emitted from the acousto-optic deflection module is split into parallel beams by a beam splitting module, thereby realizing beam splitting.

[0028] (3) The light beams output by the beam splitting module are reflected to a flat-field focusing lens by a rotating mirror rotating at a constant speed, and the light beams are converged to a focus point by the flat-field focusing lens, and the focus point is used for processing the processed part;

[0029] (4) The central control unit is connected with the rotating mirror, the signal synchronous control unit, the camera and the displacement table respectively, and the central control unit sends control signals to the signal control unit, the rotating mirror and the displacement table; the parameters pre-stored in the central control unit include the rotating speed of the rotating mirror, the moving direction of the displacement table, and the driving signal transmitted by the signal control unit to the acousto-optic deflection module so as to make the acousto-optic deflection module load a corresponding radio frequency signal frequency;

[0030] (5) The camera is used for monitoring the processing in real time, and feeding back the parameters of the processing position, the processing precision and the processing speed to the central control unit; after receiving the signals, the central control unit sends the signals to the rotating mirror, the displacement table and the signal control unit, so as to adjust the rotating speed of the rotating mirror, the moving direction of the displacement table, and the driving signal transmitted by the signal control unit to the acousto-optic deflection module, so that the processing is kept in an optimal state.

[0031] Preferably, the rotating speed V1 of the rotating mirror is:

[0032]

[0033] In the formula, L s represents the length formed on the processed part after the rotating mirror of the lens on which the laser is input rotates an angle α; N is the number of pulses output by the pulse laser when the rotating mirror of the lens on which the laser is input rotates an angle α; and F is the frequency of the pulse laser. Wherein α=360° / m, and m is the number of edges of the rotating mirror.

[0034] Overall, compared with the prior art, the above technical scheme conceived by the present application mainly has the following technical advantages:

[0035] 1. The laser micro-nano processing device based on an acousto-optic deflector and a rotating mirror provided by the present application utilizes the characteristics of high speed and inertia-free scanning of the acousto-optic deflector, wherein the deflection angle of the acousto-optic deflector is proportional to the input signal frequency, and the deflection range is proportional to the Bragg bandwidth; the deflection of the light beam is realized by high-speed regulation and control of the sound field, without any mechanical parts and mechanical inertia, and the processing efficiency is high; at the same time, the present application utilizes the characteristics of high precision of the acousto-optic deflector, and the control precision is guaranteed by the waveform precision of the acousto-optic driving source; the waveform frequency precision based on digital frequency synthesis is often better than one ten-thousandth, so that the processing quality is good.

[0036] 2. The laser micro-nano machining device based on the acousto-optic deflector and the rotating mirror provided by the application can control the acousto-optic deflector pulse by pulse within a controllable laser frequency, two acousto-optic deflector modules are orthogonally arranged to form a rectangular scanning area, the laser beam can be deflected to any position in the scanning area, and the function of dynamically controlling the beam is achieved, so that the overall system is flexible and the pulse is controllable.

[0037] 3. The laser micro-nano machining device and method based on the acousto-optic deflector and the rotating mirror provided by the application can realize parallel processing by splitting a single beam into multiple parallel beams by a beam splitting module, and greatly improve the processing efficiency.

[0038] 4. The laser micro-nano machining device based on the acousto-optic deflector and the rotating mirror provided by the application mainly uses quartz, tellurium oxide and germanium as high-damage-threshold crystals, and can withstand continuous or pulsed laser power much higher than liquid crystals, and has a very high damage threshold.

[0039] 5. The application limits the rotating speed of the rotating mirror The speed of the rotating mirror is calculated theoretically, and the rotating speed of the rotating mirror is set to run at this speed, and the acousto-optic deflection module deflects the pulse according to the given frequency, so that the designed processing pattern can be obtained by using the system, and too fast or too slow speed will cause distortion of the pattern.

[0040] 6. The application flexibly controls the deflection of the laser beam to any position in the rectangular scanning area by arranging two orthogonally arranged acousto-optic deflectors, and realizes that the polygonal rotating mirror rotates only once along the processing track, the acousto-optic deflector compensates and fills the processing pattern, realizes the technical effect of any shape such as slotting and punching, and combines the beam splitting module to split the output beam into multiple beams to realize parallel processing and meet the needs of high-speed and high-quality processing; the acousto-optic deflection module has the characteristics of ultra-high scanning speed and pulse-by-pulse deflection of the laser beam to any position in the scanning area, and the rotating mirror has the characteristics of high damage threshold and high scanning speed, and the combination of the two can meet the needs of ultra-high speed and high precision processing. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a structural schematic diagram of a laser micro-nano machining device based on an acousto-optic deflector and a rotating mirror provided by the application;

[0042] Figure 2 is a structural schematic diagram of an acousto-optic deflection module in the application;

[0043] Figure 3 is a schematic diagram of a scanning area formed by two acousto-optic deflectors in the frequency bandwidth of the application after passing through a field flattening focusing lens;

[0044] Figure 4A structure schematic diagram of a multi-plate flat plate spectroscope for beam splitting in the application;

[0045] Figure 5 A structure schematic diagram of a plurality of stereoscopic spectrometers for beam splitting in the application;

[0046] Figure 6 A structure schematic diagram of a diffraction optical element for beam splitting in the application;

[0047] Figure 7 In (a), a schematic diagram of actual processing tracks corresponding to pulses when a slotting processing effect is performed in the embodiment 1 of the application and when a deflection is not performed by using an acousto-optic deflection module; (b), a schematic diagram of corresponding position compensation by using an acousto-optic deflection module when the slotting processing is performed in the embodiment 1 of the application;

[0048] Figure 8 A parallel slotting schematic diagram of the embodiment 1 of the application by using a beam splitting device to split a light beam;

[0049] Figure 9 A schematic diagram of the embodiment 2 of the application by using only one acousto-optic deflector to deflect and combining a polygon mirror to achieve a slotting effect;

[0050] Figure 10 In (a), a schematic diagram of actual processing tracks corresponding to pulses when a punching processing effect is performed in the embodiment 3 of the application and when a deflection is not performed by using an acousto-optic deflection module; (b), a schematic diagram of corresponding position compensation by using an acousto-optic deflection module when the punching processing is performed in the embodiment 3 of the application;

[0051] Figure 11 A parallel punching schematic diagram of the embodiment 3 of the application by using a beam splitting module to split a light beam;

[0052] Figure 12 A schematic diagram of the embodiment 4 of the application by combining a displacement table to perform continuous parallel processing;

[0053] Figure 13 A schematic diagram of the embodiment 5 of the application by combining a high-speed camera and a displacement table to perform precise continuous parallel processing;

[0054] In the figure, 1, a pulse laser; 2, a beam expanding and collimating device; 3, a mirror group; 4, an acousto-optic deflection module; 5, a signal control unit; 6, a beam splitting module; 7, a rotating mirror; 8, a flat-field focusing lens; 9, a processing component; 10, a displacement table; 11, a camera; 12, a central control unit; 13, a mirror; 14, a scanning field of view; 41, a first acousto-optic deflector; 42, a second acousto-optic deflector; 61, a flat plate spectroscope module; 62, a cubic spectroscope module; 63, a diffraction optical element; 401, a driving signal source; 402, an ultrasonic transducer; 403, an acousto-optic medium. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0056] Example 1

[0057] like Figure 1 As shown, a laser micro-nano processing device based on an acousto-optic deflector and a rotating mirror includes: a pulsed laser 1, a beam expander and collimator module 2, a mirror group 3, a first acousto-optic deflector 41, a second acousto-optic deflector 42, a signal control unit 5, a beam splitter module 6, a rotating mirror 7, and a flat-field focusing lens 8 arranged sequentially.

[0058] The pulsed laser 1 is used to generate a pulsed laser beam with variable frequency and variable average power, and the frequency of the pulsed laser 1 is variable between 50 and 500 kHz.

[0059] The mirror group 3 is used to adjust the angle at which the pulsed laser output from the pulsed laser 1 enters the first acousto-optic deflector 41 and the second acousto-optic deflector 42, so as to satisfy the requirement of incident at the Bragg angle.

[0060] The signal control unit 5 simultaneously controls the first acousto-optic deflector 41 and the second acousto-optic deflector 42, loading them with radio frequency signals of the corresponding frequency, so that the beam is deflected to the designated position.

[0061] The structure of the acousto-optic deflection module 4 is as follows: Figure 2 As shown, the deflection angle (θ) of the pulsed laser output from the pulsed laser 1 is determined by the frequency (f) of the radio frequency signal, and can be expressed by the formula:

[0062]

[0063] In the formula, λ is the wavelength of the laser beam, and V s The speed at which ultrasound travels in an acousto-optic medium;

[0064] The scanning range formed by the acousto-optic deflection module 4 within the scanning bandwidth is as follows: Figure 3 As shown, the relationship between its scanning angle range and working bandwidth can be expressed as:

[0065]

[0066] The scanning field of view (L1) formed on the processing component 9 by the acousto-optic deflection module after being focused by the flat-field focusing lens 8 can be expressed by the formula:

[0067] L1 = Δθ · F

[0068] Wherein, F is the focal length of the flat field focusing lens 8;

[0069] The beam splitting module 6 splits the deflected beam output by the second acousto-optic deflector 42 into multiple parallel beams, and the number and spacing of the multiple parallel beams are determined by the settings of the beam splitting module;

[0070] Optionally, the beam splitting module 6 is arranged by multiple flat plate beam splitters, as shown in Figure 4 ;

[0071] Optionally, the beam splitting module 6 is arranged by multiple three-dimensional beam splitters, as shown in Figure 5 ;

[0072] Optionally, the beam splitting module 6 is formed by a diffractive optical element, as shown in Figure 6 ;

[0073] The rotating mirror 7 is driven by a high-speed motor and can rotate at high speed. The relationship between the rotational angular velocity (ω) and the rotation angle (α) can be represented as:

[0074]

[0075] The scanning speed (V) of the rotating mirror 7 is related to the rotational angular velocity (ω), and the relationship can be represented by the formula:

[0076] V = r · ω

[0077] Wherein, r is the radius of rotation of the rotating mirror. If the radius of rotation is determined, the scanning speed is proportional to the rotational angular velocity;

[0078] Optionally, the laser micro-nano machining device based on the acousto-optic deflector and the rotating mirror further comprises a beam expanding and collimating module 2, a displacement table 10, a camera 11 and a central control unit 12;

[0079] The beam expanding and collimating module 2 expands and collimates the pulsed laser output by the pulsed laser 1 to form a parallel beam output;

[0080] The machining component 9 is fixedly arranged on the displacement table 10 and moves with the displacement table 10;

[0081] The central control unit 12 pre-stores the processing method of the processing component 9 and its related data of transformation, and is connected with the signal control unit 5, the rotating mirror 7, the displacement table 10 and the camera 11, for controlling the rotating speed of the rotating mirror 7, the moving direction of the displacement table 10, the driving signal of the signal control unit 5 to the first and second acousto-optic deflection modules 41 and 42, so as to load the corresponding radio frequency signal frequency, and to carry out the pre-set processing procedure. The camera 11 monitors the processing surface in real time and compares with the pre-set data in real time. When the data is different, it feeds back to the central control unit 12 to adjust the parameters to achieve the expected effect.

[0082] Reference Figure 2 The acousto-optic deflection module 4 includes a first acousto-optic deflector 41 and a second acousto-optic deflector 42, which are composed of a driving signal source 401, an ultrasonic transducer 402 and an acousto-optic medium 403. The ultrasonic transducer 402 is composed of several layers of medium attached to the surface of the acousto-optic medium 403, and the electrode layers at both ends of the piezoelectric layer are connected with the driving signal source 401. When the first and second acousto-optic deflectors 41 and 42 are working, the driving signal source 401 can output radio frequency signals of different frequencies, and the ultrasonic transducer 402 realizes the change from mechanical vibration to acoustic signals of the same frequency at the position, so as to produce ultrasonic waves in the acousto-optic medium 403, so that the refractive index of the acousto-optic medium 403 changes. In this embodiment, the material of the acousto-optic medium 403 is quartz crystal, the material of the ultrasonic transducer 402 is lithium niobate crystal, and the frequency range of the radio frequency signal output by the driving signal source 401 is 140MHz-200MHz, and the center frequency is 170MHz.

[0083] The first and second acousto-optic deflectors 41 and 42 are the same type of acousto-optic deflector, which produces corresponding angle deflection of the light beam according to the control signal of the signal control unit 5.

[0084] Reference Figure 3 The incident laser beam is scanned in the scanning bandwidth range after passing through the first and second acousto-optic deflection modules 41 and 42 to obtain the deflected light beam output, and then passes through the flat-field focusing lens 8 to form a scanning field of view. In this embodiment, the focal length of the flat-field focusing lens 8 is 100mm, and the frequency of the output of the pulsed laser 1 is 355nm, so the side length of the obtained scanning field of view 14 is calculated as

[0085] L1=370um.

[0086] Reference Figure 4The deflected beam output by the acousto-optic deflection module is split into n parallel beams by the beam splitting module 6. The beam splitting module consists of n flat beam splitters, and the spacing between the parallel beams is determined by the spacing between the flat beam splitters.

[0087] refer to Figure 7 In (a), when the signal control unit 5 of the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42 provides a center frequency of 170MHz to both, the deflected beam is emitted in parallel (adjusted with the diffraction deflection direction at the center frequency as the horizontal direction), and the emitted light spot does not undergo relative deflection. It is then scanned at high speed by the polygonal rotating mirror 7, and the resulting processing trajectory is as follows: Figure 7 The red dots shown in (a) are used to obtain... Figure 7 In the actual processing of the pattern in (a), the position of the pulse beam needs to be controlled by the acousto-optic deflection module, so that the laser pulse originally located at the red dot is deflected by the acousto-optic deflection module and placed at the gray dot. This embodiment illustrates that 5 light pulses are deflected in the normal direction of the hexagonal rotating mirror. It should be noted that the spacing between the pulse lasers and the number of deflections are determined by the scanning field of view 14 formed by the acousto-optic deflection module and its own deflection capability, and are not limited to the spacing and number of deflections shown in this figure.

[0088] refer to Figure 7 As shown in (b), the deflection position required by the first acousto-optic deflection module 41 and the second acousto-optic deflection module 42 is the actual processed pulse mark minus the pulse mark when no deflection occurs. The resulting relative deflection position is processed by the central control unit 12 and becomes the frequency signal in the signal control unit 5. When the signal control unit 5 provides the frequency signal to the acousto-optic deflection modules (41 and 42), the acousto-optic deflection modules deflect the laser beam pulse by pulse. At the same time, the central control unit 12 controls the movement speed of the rotating mirror 7 to match the overlap rate and other parameters of the designed processing pattern, and finally completes the processing task of the processing pattern.

[0089] refer to Figure 8 After the beam is split by the beam splitting module 6, the resulting multi-parallel beams are processed by the high-speed scanning of the polygonal rotating mirror, as shown in the processing trajectory. Figure 8 As shown. The processing width formed by each beam depends on the scanning width (L1) formed by the acousto-optic deflection module. In this embodiment, the maximum processing width formed by each beam is 370µm. The distance between two beams is defined by the beam-splitting module distance of the beam-splitting module 6. The width of each beam and the distance between two beams can be defined according to the actual processing pattern to meet the processing requirements.

[0090] Example 2

[0091] On the basis of embodiment one, this embodiment provides another processing method, only using one horizontally placed acousto-optic deflector 41, using the acousto-optic deflector 41 to control the position of each laser pulse and whether deflection occurs, to achieve the processing effect.

[0092] Reference Figure 9 By controlling the signal control unit 5, a signal with a center frequency of 170 MHz is sent to the acousto-optic deflector 42 during processing, so that the acousto-optic deflector 42 only deflects the pulse at the center frequency. The signal control unit 5 sends a bandwidth frequency to the acousto-optic deflection module 41, and the bandwidth frequency is 140-200 MHz, so that the deflected light beam scans in the horizontal direction (the horizontal direction is perpendicular to the rotation direction of the polygon mirror). During processing, the signal control unit 5 always sends a bandwidth frequency to the acousto-optic deflection module 41, so that it scans back and forth in the horizontal direction without inertia, or according to the processing pattern width, calculates the required number of deflections according to the pulse overlap rate, and then scans back and forth at the corresponding frequency in this frequency range. During the process of deflecting and scanning the light beam by the acousto-optic deflection module 4, the rotating mirror 7 scans at a high speed, and the processing pattern is as shown in the figure. Figure 9 The degree of staggering of the two laser pulses perpendicular to the movement direction of the rotating mirror 7 is determined by the rotation speed of the rotating mirror 7; the overlap rate of the two laser pulses horizontal to the movement direction of the rotating mirror 7 is still a set parameter. Since the acousto-optic deflection module has a pulse-by-pulse control capability, the signal control unit 5 does not send a frequency signal to the acousto-optic deflection module 4 at the beginning and end of processing (at this time, the laser pulse does not deflect), so that the laser pulse cannot be projected onto the processing surface as shown in the figure. Figure 9 The hollow circle represents the pulse that is not projected onto the processing surface, and at this time, a rectangular area can still be processed.

[0093] Only one acousto-optic deflection module is used in the device, and the signal control unit 5 only controls this acousto-optic deflection module to perform the above operations, so that the device is more simple. The beam splitting module 6 can also be a combination of several cube beam splitters, as shown in Figure 5 The deflected light beam is split.

[0094] The embodiment of the application only uses one acousto-optic deflector, uses the feature that the acousto-optic deflector can deflect the laser beam pulse by pulse, and shields the laser pulse at a specific position, to achieve the processing effect of two orthogonally placed acousto-optic deflection modules, to meet the beneficial effects of special processing needs, and the structure is simpler and the output is more reliable.

[0095] Embodiment 3

[0096] On the basis of embodiment one, the embodiment provides another processing effect, which can be used for punching. The processing device based on the acousto-optic deflector and the rotating mirror makes the processing system based on the polygon rotating mirror not only suitable for high-speed straight-line scanning, but also greatly expands the application range of the polygon rotating mirror.

[0097] Reference Figure 10 In the application, similar to the processing mode of embodiment one, when the signal control unit 5 provides the central frequency to the acousto-optic deflection module 4, the light beam is at the central position of the deflection range. When the rotating mirror 7 moves at a high speed, a red dot trace is formed, as shown in (a) of Figure 10 If hole processing is to be performed, the number of pulse points required for punching is sorted, and then the trace when no relative deflection occurs is subtracted to obtain the relative deflection position of the acousto-optic deflection module to the laser pulse, as shown in (b) of Figure 10 When processing is performed, the frequency of the selected pulse laser 1 is selected as the frequency used for laser processing. The central control unit 12 stores all the relative deflection position data and converts it into a frequency signal in the signal control unit 5. The signal control unit 5 provides the frequency signal to the acousto-optic deflection module. The acousto-optic deflection module deflects in turn according to the given frequency. The central control unit 12 controls the rotation speed of the rotating mirror 7 at the same time. Finally, the processing pattern is obtained.

[0098] Reference Figure 11 After splitting by the multi-plate splitting module 61 (as shown in Figure 4 The processing trace formed by high-speed scanning of the multi-parallel light beams generated after splitting by the multi-plate splitting module 61 through the polygon rotating mirror is as shown in Figure 11 The processing width formed by each splitting depends on the scanning width (L1) formed by the acousto-optic deflection module. In the embodiment, the maximum diameter of the single hole formed by each splitting is 370 um. The distance between two splittings is defined by the splitting module distance of the splitting module 6. The width of each splitting and the distance between two splittings can be defined according to the actual processing pattern to meet the processing requirements.

[0099] In an alternative embodiment, the multi-plate splitting module 61 can also be a combination of several cubic beam splitters.

[0100] In the embodiment, the radio frequency signal of a specified frequency is applied to two orthogonally placed acousto-optic deflection modules, so that the laser light beam can be deflected anywhere in the scanning range, and can be scanned into any pattern. The embodiment not only expands the application range of the polygon rotating mirror, but also provides a new scanning strategy, greatly improves the processing efficiency, and meets the needs of high-speed and efficient processing.

[0101] Embodiment 4

[0102] On the basis of the above-mentioned embodiments, the displacement table 10 can realize micro-nano processing in a super-large range, meeting the demand of laser micro-nano processing of a larger format.

[0103] With reference to Figure 12 After the rotating mirror 7 rotates at a high speed, corresponding processing patterns are processed on the processing plane, the beam splitting module 6 splits a deflected light beam into multiple light paths, and the light beam passes through the rotating surface of the polygon rotating mirror 7 once, so that several patterns can be processed on the processing plane, greatly improving the processing efficiency.

[0104] In the embodiment of the application, a radio frequency signal of a specified frequency is applied to two orthogonally placed acousto-optic deflection modules, so that the laser beam can be deflected in any scanning range, and meanwhile, the displacement table 10 is introduced to dynamically adjust the processing position in the processing process, which not only improves the processing efficiency but also provides a larger processing format, meeting the demand of high-speed and super-large format processing.

[0105] Embodiment 5

[0106] On the basis of the above-mentioned embodiments, the displacement table 10 can realize micro-nano processing in a super-large range, meeting the demand of laser micro-nano processing of a larger format.

[0107] With reference to Figure 13The central control unit 12 controls the displacement table 10 to move to the next machining position, and then the camera 11 captures the position of the displacement table 10 in real time, and when it is detected that the displacement table 10 reaches the specified machining position, the high-speed camera 11 feeds back a position signal to the central control unit 12, and the central control unit 12 sends a signal to the signal control unit 5, so that the signal control unit 5 provides a corresponding frequency signal, so that the laser pulse is deflected again after passing through the acousto-optic deflection module 4, and at the same time, the central control unit 12 controls the rotation speed of the polygon mirror 7, so that the acousto-optic deflection module 4 and the polygon mirror 7 cooperate to complete the machining together, and in the machining process, the high-speed camera 11 monitors the machining condition of the machining surface in real time, and when the machining depth and quality of the machining surface meet the machining requirements, the high-speed camera 11 feeds back a signal to the central control unit 12, and the central control unit 12 sends a signal to the signal control unit 5 according to the feedback information to stop the deflection of the laser pulse, and at the same time, the central control unit 12 also sends a corresponding displacement instruction to the displacement table 10, and when the displacement table 10 moves to the next machining surface, the high-speed camera 11 feeds back a signal to the central control unit 12, and the central control unit 12 sends a command to the signal control unit 5 again, and the above operation is repeated until the machining is completed.

[0108] The embodiment of the present application introduces a high-speed camera, which can monitor the machining condition of the machining surface in real time during the machining process and feed back the machining condition in real time, thereby improving the machining quality of the super-large format machining and the machining efficiency.

[0109] The present application provides a laser micro-nano machining method based on an acousto-optic deflector and a polygon mirror, which is applied to a laser micro-nano machining device based on an acousto-optic deflector and a polygon mirror, can realize efficient laser micro-nano machining, improve the machining speed, and further improve the machining efficiency, while ensuring the machining quality, and can process according to the machining pattern required by the user, and meet various actual needs.

[0110] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A processing method of a laser micro-nano processing device based on an acousto-optic deflector and a rotating mirror, characterized in that, The laser micro-nano processing device comprises: a pulse laser (1), a mirror group (3), an acousto-optic deflection module (4), a signal control unit (5), a beam splitting module (6), a rotating mirror (7), and a flat-field focusing lens (8); the pulse laser (1) is used for providing pulse laser; the mirror group (3) is used for reflecting the laser output by the pulse laser (1) into the acousto-optic deflection module (4) and keeping the laser to be incident on the acousto-optic deflection module (4) at a Bragg angle to change the deflection position of the laser; the acousto-optic deflection module (4) comprises a first acousto-optic deflector (41) and a second acousto-optic deflector (42), the first acousto-optic deflector (41) and the second acousto-optic deflector (42) are placed orthogonally, the first acousto-optic deflector (41) and the rotating shaft of the rotating mirror (7) are placed parallel to each other, and the second acousto-optic deflector (42) and the rotating shaft of the rotating mirror (7) are placed perpendicular to each other; a rectangular scanning area is formed by using two orthogonally placed acousto-optic deflectors; the signal control unit (5) controls the acousto-optic deflection module (4) to input a set frequency signal into the acousto-optic deflection module (4); the beam splitting module (6) is used for splitting the laser into beams parallel to each other to realize beam splitting; the rotating mirror (7) is used for reflecting the parallel beams to the flat-field focusing lens (8), the flat-field focusing lens (8) is used for converging the beams at a focal point, and the focal point is used for placing a component to be processed; the laser micro-nano processing device further comprises a beam expanding and collimating device (2), a processing component (9), a displacement table (10), a camera (11), and a central control unit (12); the beam expanding and collimating device (2) is arranged between the pulse laser (1) and the mirror group (3) and is used for expanding and collimating the laser output by the pulse laser (1) to be emitted; the processing component (9) is fixedly arranged on the displacement table (10) and can move with the displacement table (10); the camera (11) is used for monitoring the processing of the processing component (9) in real time and feeding back in real time; the central control unit (12) is connected with the rotating mirror (7), the signal control unit (5), the camera (11), and the displacement table (10) respectively; the processing method is specifically as follows: (1) the pulse laser provides pulse laser, the laser passes through the beam expanding and collimating device and then is reflected by the mirror group to be incident on the acousto-optic deflection module at a Bragg angle; the acousto-optic deflection module is controlled by the frequency signal from the signal control unit to change the deflection angle of the beams emitted from the acousto-optic deflection module; (2) the laser emitted from the acousto-optic deflection module is split into beams parallel to each other by the beam splitting module to realize beam splitting; (3) the split light output by the beam splitting module is reflected to the flat-field focusing lens by the rotating mirror rotating at a constant speed, the beams are converged at a focal point by the flat-field focusing lens, and the focal point is used for processing the processing component. (4) The central control unit is connected with the rotating mirror, the signal control unit, the camera and the displacement table respectively, and the central control unit sends control signals to the signal control unit, the rotating mirror and the displacement table; the parameters stored in the central control unit in advance include the rotating speed of the rotating mirror, the moving direction of the displacement table and the driving signal sent by the signal control unit to the acousto-optic deflection module so as to make the acousto-optic deflection module load the corresponding radio frequency signal frequency; (5) The camera is used to monitor the processing situation in real time, and feedback the parameters of the processing position, the processing precision and the processing speed to the central control unit; after receiving the signals, the central control unit sends the signals to the rotating mirror, the displacement table and the signal control unit, so as to adjust the rotating speed of the rotating mirror, the moving direction of the displacement table and the driving signal sent by the signal control unit to the acousto-optic deflection module, and make the processing keep the optimal state.

2. The method according to claim 1, wherein the method is characterized by: The first acousto-optic deflector (41) and the second acousto-optic deflector (42) both include a driving signal source (401), an ultrasonic transducer (402) and an acousto-optic medium (403); the acousto-optic medium (403) is connected with the ultrasonic transducer (402), the electrode on the ultrasonic transducer (402) is connected with the driving signal source (401), and the signal control unit (5) is connected with the driving signal source (401).

3. The method according to claim 2, wherein the method is characterized by: The material of the acousto-optic medium (403) is selected from quartz, tellurium oxide and germanium.

4. The method of claim 1, wherein the method further comprises: The beam splitting module (6) is selected from a flat plate beam splitter, a cubic beam splitter and a diffractive optical element.

5. The method of claim 1, wherein the method further comprises: The rotating mirror is positive The edge-shaped cylinder is is 3-16.

6. The method of claim 1, wherein the method further comprises: The laser micro-nano processing device further includes a motor, and the motor is connected with the rotating mirror (7).

7. The method of claim 1, wherein the method further comprises: The rotation speed of the rotating mirror is: In the formula, L s represents the length formed on the machined part after the rotating mirror rotates an angle of α on the lens on which the laser is incident, N is the number of pulses output by the pulse laser when the rotating mirror rotates an angle of α on the lens on which the laser is incident, and F is the frequency of the pulse laser; wherein α = 360° / m, and m is the number of edges of the rotating mirror.

Images