CN115338533A - Scanning method for accurate and controllable track of femtosecond laser beam - Google Patents

Abstract

The invention discloses a scanning method for accurate and controllable femtosecond laser beam trajectory. The incident beam of the research focusing lens is translated, so that the translation direction is opposite to the beam deflection direction, and the translation distance is at least greater than half of the beam diameter. , to ensure that the edge of the beam is greater than zero with the axis of the hole in the direction of light propagation, rotate around the optical axis and feed layer by layer to realize the forming of the inverted cone hole; at the same time, coordinate programming control in the three directions of X/Y/Z , and conduct process tests including factors affecting taper such as power, focus position, and scanning time, to realize the development of high-precision control process technology for hole-making taper.

Description

A scanning method for accurate and controllable femtosecond laser beam trajectory

【Technical field】

The invention belongs to the technical field of femtosecond laser processing, and in particular relates to a scanning method for accurate and controllable femtosecond laser beam trajectory.

【Background technique】

Since the advent of laser, laser micro-nano processing technology has been one of the main means of micro-nano processing technology. Laser direct writing micro-nano processing technology refers to the use of adjustable intensity laser beams to directly expose the surface of the material to form the desired micro-nano structure. Compared with traditional long-pulse laser, femtosecond laser has less processing energy loss and higher utilization rate. Due to its non-pollution, non-contact, low damage threshold, high processing precision and cold working characteristics, femtosecond laser micro-nano processing provides a new method for preparing large-area micro-nano structures, and its successful applications have covered microelectronics. , bionics, materials chemistry and many other fields.

Traditional micro-hole processing technologies mainly include mechanical processing, electric spark, chemical corrosion, ultrasonic drilling and other technologies. These technologies have their own characteristics, but they can no longer meet the higher requirements of micro-hole processing. In order to obtain the best fuel injection atomization effect and improve fuel combustion efficiency, some automotive injection parts are required to process nozzle holes with different hole tapers.

At present, there are related researches, such as Chinese patent application number CN201910299942.7, a femtosecond laser processing array microhole system based on spatial beam shaping, using the spatial light modulator SLM, by designing different phases, a single femtosecond beam The laser is shaped into a multi-beam array light field with a specific spatial distribution, the laser repetition frequency, the laser beam waist radius, and the laser pulse energy are adjusted, and finally the optical path is built through optical devices to focus the shaped femtosecond laser on the sample surface, realizing in a variety of The high-quality, non-contact, high-efficiency, large-area array microhole processing on materials is highly repeatable and flexible. The invention system is applied to array microhole processing, effectively avoiding the dispersion caused by the Gaussian distribution of the laser itself. Beam inhomogeneity improves the uniformity and quality of arrayed microholes. The number and distribution of arrayed microholes can be freely adjusted by changing the phase loaded by the spatial light modulator. It is highly adjustable without configuring multiple components.

In the process of micro-nano processing, using laser direct writing technology, a single laser beam can create a single micro-hole structure on the material after being focused by a lens, which severely restricts the efficiency of large-area micro-hole array preparation. In addition, for linearly polarized single laser beam focusing, the aspect ratio of the processed microholes is also very low.

At present, most of the fuel injection holes are processed by EDM technology, and some of them are processed by long pulse laser. These two processing methods are all hot-melt processing. The accuracy is also difficult to meet the requirements of the "National Six" emission standards. Many institutions at home and abroad have carried out a lot of development and research work on related processing technology and equipment, but the engineering application of this kind of high-accuracy inverted cone nozzle hole processing still needs further research.

【Content of invention】

For the processing of fuel injection holes in the prior art, EDM technology or long-pulse laser processing is mostly used. These two processing methods belong to hot-melt processing, and defects such as burrs and residues will be formed on the edge and wall of the hole during the processing process. , the invention provides a scanning method for accurate and controllable femtosecond laser beam trajectory.

The object of the present invention is achieved through the following technical solutions:

The inventor will study the translation of the incident beam of the focusing lens, so that the translation direction is opposite to the beam deflection direction, and the translation distance is at least greater than half of the beam diameter, so as to ensure that the edge of the beam is greater than zero with the axis of the hole in the direction of light propagation. The shaft rotates and feeds layer by layer to realize the forming of the inverted taper hole; at the same time, coordinate programming control in the three directions of X/Y/Z, and conduct process tests including power, focus position, scanning time and other factors that affect the taper , to realize the development of high-precision control technology for hole taper.

In the present invention, the offset P when the beam changes with the rotation angle:

Processing aperture r:

Processing hole taper β:

为偏转光楔相对于初始合成偏转角为0时两光楔的相对转角、φ为两个平行平板相对于最小偏移量状态的相对转角、h表示两平行平板厚度之和、d为激光光束直径、n表示光楔和平板材料的折射率。Where f is the focal length of the focusing lens, θ ₁ is the tilt angle of the parallel plate relative to the horizontal direction, θ ₂ is the angle of the deflecting wedge,

is the relative rotation angle of the deflection wedges relative to the initial combined deflection angle of 0, φ is the relative rotation angle of the two parallel plates relative to the minimum offset state, h represents the sum of the thicknesses of the two parallel plates, and d is the laser beam The diameter, n, represents the refractive index of the wedge and slab material.

The femtosecond laser beam track precision control scanning system provided by the present invention includes an industrial computer, a femtosecond laser, a cooperative control system, a laser control module, a beam deflection module, a beam translation module, a beam expander, a deflection wedge group, and a parallel plate group , and parameter control modules such as scanning distribution, speed, laser power, and taper; the beam expander includes a concave lens and a first convex lens, the deflection wedge group includes an upper deflection wedge and a lower deflection wedge, and the parallel plate group includes an upper plate of a parallel plate group And the lower plate of the parallel plate group, the concave lens, the first convex lens, the total reflection prism, the upper deflection wedge, the lower deflection wedge, the upper plate of the parallel plate group, the lower plate of the parallel plate group, and the focusing convex lens are sequentially arranged on the output light of the femtosecond laser On the road; the laser control module controls the femtosecond laser, the beam deflection control module controls the upper deflection wedge and the lower deflection wedge of the deflection wedge group, and the beam translation control module controls the upper plate of the parallel plate group and the lower plate of the parallel plate group; the laser control module , The beam deflection control module and the beam translation control module are connected to the cooperative control system through the data line, and the cooperative control system is connected to the industrial computer through the data line;

The beam translation control module described therein controls the upper plate of the parallel plate group and the lower plate of the parallel plate group, controls the beam translation distance by controlling the deflection angle of the plates, and can conveniently, quickly and accurately realize the beam around the optical axis during high-speed rotation Rotate and feed layer by layer to realize the processing and forming of the inverted taper hole;

The wedge angle of the upper deflecting wedge and the lower deflecting wedge is ≤5°, and there is a gas gap between the upper deflecting wedge and the lower deflecting wedge, the upper deflecting wedge and the lower deflecting wedge rotate relatively around the optical axis, and the light beam After passing through the optical wedge, an angle is formed with the optical axis, which is equal to the combined angle of the two deflecting wedges; when the direction of the wedge angle of the two deflecting wedges is opposite, the resulting deflection angle is 0°, and the double wedge The effect is equivalent to a parallel plate, and the light only produces a small offset of the upper and lower positions; when the wedge angle directions of the two deflecting wedges are the same, that is, the relative rotation of the two deflecting wedges is 180°, the deflection angle generated at this time is the largest It is twice the deflection angle generated by a single optical wedge; if the relative rotation angle of two optical wedges is 360°, then the maximum deflection angle is reversed;

The upper deflection wedge and the lower deflection wedge mentioned above rotate relatively around the optical axis, and the optical axis is the optical path. This included angle is obtained through a detailed calculation process and is a dynamic angle, not a static angle; The optical axis produces an included angle, which is equal to the composite angle of the two deflection wedges. This composite angle is obtained through a detailed calculation process and is a dynamic angle;

The parallel plate group is composed of two equal-thick parallel plates. When a light beam with a certain angle is incident on the parallel plate, the relative rotation angle of the two parallel plates is controlled by the driving motor, and the outgoing beam will have an angle relative to the incident light beam. Displacement offset; when the inclination angle of the parallel plate is constant, the offset is the largest when the two plates are parallel; when the two plates are complementary (when the translation amount is 0), and there is mutual rotation between the two, the offset is between 0° and 90° In the range of , the plate offset will increase with the increase of the relative rotation angle.

The beam emitted by the laser first passes through the beam expander to expand and collimate the beam, then passes through the deflection wedge group and forms a small angle with the optical axis, then passes through the parallel plate group to produce a certain translation, and then passes through the focusing lens to focus On the focal plane with a small distance away from the optical axis; when the deflection wedge group and the parallel plate group rotate at high speed synchronously, a circular trajectory will be formed on the focal plane, which can be realized by changing the relative deflection angle of the optical wedge and the relative rotation angle of the parallel plate in real time Processing of micro-holes with large depth-to-diameter ratio and controllable taper.

Adjust the beam offset by changing the inclination angle between the parallel plate and the horizontal direction; adjust the processing aperture by changing the synthesis angle of the deflection wedge and the focal length of the focus lens; change the total thickness of the parallel plate, beam diameter, distance from the lower wedge to the focus lens and The focal length of the focusing lens adjusts the taper of the machining hole.

Therefore, as long as the relative rotation angle of the double optical wedge and the inclination of the parallel plate are precisely controlled, the machining track can be programmed and the hole shape can be controlled.

The present invention also relates to a scanning method for accurate and controllable femtosecond laser beam trajectory, comprising the following steps:

1) The above-mentioned femtosecond laser beam trajectory is precisely controlled in the scanning system. The beam emitted by the femtosecond laser in the scanning system first passes through the beam expander to expand and collimate the beam, and then passes through the total reflection prism to reach the upper deflection wedge of the deflection wedge group. Through the lower deflection wedge of the deflection wedge group, the deflection wedge group can realize the precise deflection of the beam under the condition of controlling the precision of the rotation angle;

2) The deflected beam enters the upper plate of the parallel plate group and the lower plate of the parallel plate group, and the difference in angle between the upper plate of the parallel plate group and the lower plate of the parallel plate group can accurately realize the translation distance of the beam;

3) The beam after translation enters the focusing convex lens, and the focused beam reaches the workpiece. Under the precise control of parameters such as industrial computer comprehensive control scanning distribution, motor speed, laser power, taper, etc., precise processing is carried out.

Compared with the prior art, the present invention has the following advantages:

1. The femtosecond laser beam track precise control scanning system described in the present invention, as the core device of laser ultra-fine hole making, is the key technology to control the laser beam to realize high-precision cylindrical hole, tapered hole and special-shaped hole processing, and also to realize no thermal effect An important means of micromachining. The system mainly includes the processing system of the beam rotary cutting scanning device. The beam rotary cutting scanning device uses an ultra-high parallelism flat plate to realize the programmable translation control of the beam, and is combined with a high-precision deflection wedge (≤0.1°) Synchronous rotation, to meet the beam micro-helical rotary cutting scanning, and the scanning path can be reasonably planned according to the processing requirements, suitable for high-precision and high-quality micro-hole processing with controllable aperture and taper. At the same time, the structural design of ceramic ball bearing support and ultra-lightweight rotor is adopted to realize the high-speed, long-life and high-reliability operation of the scanning module; the operating status monitoring technology ensures the stability and reliability of the scanning module.

2. A scanning method for accurate and controllable femtosecond laser beam trajectory according to the present invention, by controlling the synchronous movement of the double optical wedge and the parallel plate, the laser beam can realize synchronous dynamic translation during the processing process and change the deflection The angle can change the amount of lateral shift of the beam, so as to realize the precise and controllable taper of the processed hole, breaking through the ultra-precision and good surface integrity of the ultra-precision and good surface integrity machining of micro-holes with large K-factor inverted cones, which are difficult to achieve in traditional EDM.

【Description of drawings】

Fig. 1 is the figure of the femtosecond laser beam track precise control scanning system in the embodiment of the present invention;

Fig. 2 is a schematic diagram of the synthesis angle of the deflection wedge in the embodiment of the present invention;

Fig. 3 is a schematic diagram of the offset of the parallel plate group in the embodiment of the present invention;

Fig. 4 is the schematic diagram of femtosecond laser processing different hole types in the embodiment of the present invention;

Fig. 5 is a schematic diagram of a trajectory programmable scanning processing method in an embodiment of the present invention;

Fig. 6 is the comparison diagram of the scanning method processing and electric discharge machining of the femtosecond laser beam trajectory of embodiment 1 (Fig. 6a is the figure of electric discharge machining microhole, and Fig. 6b is the accurate and controllable scanning of femtosecond laser beam trajectory method for processing micropores)

Reference signs:

1. The upper deflection wedge; 2. The lower deflection wedge; 3. The upper plate of the parallel plate group; 4. The lower plate of the parallel plate group; 5. The focusing convex lens; 6. The workpiece to be processed.

【Detailed ways】

The specific implementation of the present invention will be further described below in conjunction with the examples.

Example:

A scanning method for accurate and controllable femtosecond laser beam trajectory, comprising the following steps:

1) Precise control of the femtosecond laser beam trajectory in the scanning system. The beam emitted by the femtosecond laser in the scanning system first passes through the beam expander to expand and collimate the beam, and then passes through the total reflection prism to reach the upper deflection wedge 1 of the deflection wedge group. Through the lower deflection wedge 2 of the deflection wedge group, the deflection wedge group can realize the precise deflection of the beam under the condition of controlling the precision of the rotation angle;

2) The deflected light beam enters the upper plate 3 of the parallel plate group and the lower plate 4 of the parallel plate group, and the difference in the angle between the upper plate 3 of the parallel plate group and the lower plate 4 of the parallel plate group can accurately realize the translational distance of the beam;

3) The translated light beam enters the focusing convex lens 5, and the focused light beam reaches the workpiece, and is precisely processed under the precise control of parameters such as scanning distribution, motor speed, laser power, taper and other comprehensive control of the industrial computer;

The femtosecond laser beam trajectory precise control scanning system includes an industrial computer, a femtosecond laser, a cooperative control system, a laser control module, a beam deflection module, a beam translation module, a beam expander, a deflection wedge group, and a parallel plate group, And parameter control modules such as scanning distribution, speed, laser power, taper; the beam expander includes a concave lens and a first convex lens, the deflection wedge group includes an upper deflection wedge 1 and a lower deflection wedge 2, and the parallel plate group includes a parallel plate group upper Plate 3 and the lower plate 4 of the parallel plate group, concave lens, first convex lens, total reflection prism, upper deflection wedge 1, lower deflection wedge 2, upper plate 3 of the parallel plate group, lower plate 4 of the parallel plate group, and focusing convex lens 5 in order Set on the output optical path of the femtosecond laser; the laser control module controls the femtosecond laser, the beam deflection control module controls the upper deflection wedge 1 and the lower deflection wedge 2 of the deflection wedge group, and the beam translation control module controls the upper plate of the parallel plate group 3 and the lower plate 4 of the parallel plate group; the laser control module, the beam deflection control module, and the beam translation control module are connected to the cooperative control system through data lines, and the cooperative control system is connected to the industrial computer through data lines;

The beam translation control module described therein controls the upper plate 3 of the parallel plate group and the lower plate 4 of the parallel plate group, controls the beam translation distance by controlling the deflection angle of the plates, and can conveniently, quickly and accurately realize the beam rotation during high-speed rotation. The optical axis rotates and feeds layer by layer to realize the processing and forming of the inverted taper hole;

The wedge angle of the upper deflecting wedge 1 and the lower deflecting wedge 2 is ≤5°, and there is a gas gap between the upper deflecting wedge 1 and the lower deflecting wedge 2, and the upper deflecting wedge 1 and the lower deflecting wedge 2 can Relatively rotating around the optical axis, the light beam will form an angle with the optical axis after passing through the optical wedge, which is equal to the combined angle of the two deflecting wedges; when the wedge angles of the two deflecting wedges are in opposite directions, the resulting deflection When the angle is 0°, the role of the double wedge is equivalent to a parallel plate, and the light only produces a small offset in the upper and lower positions; when the direction of the wedge angle of the two deflecting wedges is the same, the relative rotation of the two deflecting wedges is 180° , the maximum deflection angle produced at this time is twice the deflection angle produced by a single optical wedge; if the relative rotation angle of two optical wedges is 360°, the maximum reverse deflection angle will be generated;

The upper deflection wedge 1 and the lower deflection wedge 2 are relatively rotated around the optical axis, and the optical axis is the optical path. This included angle is obtained through a detailed calculation process and is a dynamic angle, not a static angle; the light beam passes through the optical wedge Finally, an angle is formed with the optical axis, which is equal to the composite angle of the two deflection wedges. This composite angle is obtained through a detailed calculation process and is a dynamic angle;

The parallel plate group is composed of two equal-thick parallel plates. When a light beam with a certain angle is incident on the parallel plate, the relative rotation angle of the two parallel plates is controlled by the driving motor, and the outgoing beam will have an angle relative to the incident light beam. Displacement offset; when the inclination angle of the parallel plates is constant, the offset is the largest when the two plates are parallel; when the two plates are complementary, the translation amount is 0, and there is mutual rotation between the two plates, in the range of 0° to 90° Within the range, the plate offset will increase with the increase of the relative rotation angle;

The beam emitted by the laser first passes through the beam expander to expand and collimate the beam, then passes through the deflection wedge group and forms a small angle with the optical axis, then passes through the parallel plate group to produce a certain translation, and then passes through the focusing lens to focus On the focal plane with a small distance away from the optical axis; when the deflection wedge group and the parallel plate group rotate at high speed synchronously, a circular trajectory will be formed on the focal plane, which can be realized by changing the relative deflection angle of the optical wedge and the relative rotation angle of the parallel plate in real time Processing of micro-holes with large depth-to-diameter ratio and controllable taper;

Adjust the beam offset by changing the inclination angle between the parallel plate and the horizontal direction; adjust the processing aperture by changing the deflection wedge synthesis angle and the focal length of the focusing lens; by changing the total thickness of the parallel plate, beam diameter, distance from the lower wedge to the focusing lens and The focal length of the focusing mirror adjusts the taper of the machining hole.

Figure 1 is a scanning system for precise control of femtosecond laser beam trajectory;

Fig. 2 Schematic diagram of deflection wedge synthesis angle;

Figure 3 is a schematic diagram of the offset of the parallel plate group;

Fig. 4 Schematic diagram of femtosecond laser processing of different hole types;

Fig. 5 is a schematic diagram of the trajectory programmable scanning processing method.

Comparative example:

Most of the traditional fuel injection holes are processed by EDM. The EDM method is as follows:

During EDM, the tool electrode and the workpiece are respectively connected to the two poles of the pulse power supply, and immersed in the working fluid, or the working fluid is filled into the discharge gap, and the tool electrode is controlled to feed the workpiece through the gap automatic control system. When the gap between the two electrodes When the gap reaches a certain distance, the pulse voltage applied on the two electrodes will break down the working fluid and generate spark discharge.

A large amount of heat energy is concentrated instantaneously in the tiny channel of discharge, the temperature can be as high as 10,000 degrees Celsius, and the pressure also changes sharply, so that a small amount of metal material on the working surface immediately melts and gasifies, and splashes into the working fluid in an explosive manner During the process, it condenses rapidly to form solid metal particles, which are taken away by the working fluid; at this time, a tiny pit trace is left on the surface of the workpiece, the discharge pauses briefly, and the working fluid between the two electrodes returns to the insulating state; then, the next step A pulse voltage breaks down at another point where the two electrodes are relatively close to each other, generating spark discharge, and repeating the above process; in this way, although the amount of metal removed by each pulse discharge is very small, because there are tens of thousands of pulses per second Under the condition of maintaining a constant discharge gap between the tool electrode and the workpiece, the metal of the workpiece can be etched away while the tool electrode is continuously fed to the workpiece, and finally Then process the shape corresponding to the shape of the tool electrode.

Due to the melting pits generated during the spark discharge process, the machined surface is rough and the machining accuracy is low.

Fig. 6 is a processing comparison diagram between electric discharge machining and the scanning method of the femtosecond laser beam trajectory in embodiment 1 (Fig. 6a is a diagram of electric discharge machining microholes, and Fig. 6b is a scanning method with accurate and controllable femtosecond laser beam trajectory method for processing micropores).

The above description is only the preferred embodiment of the present invention. It should be pointed out that those skilled in the art can make some improvements and changes without departing from the inventive concept of the present invention, and these all belong to the protection of the present invention. scope.

Claims (5)

1. A scanning method for accurate and controllable femtosecond laser beam trajectory, characterized in that: comprising a femtosecond laser beam trajectory precise control scanning system, containing industrial computer, femtosecond laser, cooperative control system, laser control module, beam Deflection module, beam translation module, beam expander, deflection wedge group, parallel plate group, and parameter control modules such as scanning distribution, speed, laser power, taper; the beam expander includes a concave lens and a first convex lens, and the deflection wedge group includes The upper deflection wedge (1) and the lower deflection wedge (2), the parallel plate group includes the upper plate (3) of the parallel plate group and the lower plate (4) of the parallel plate group, a concave lens, a first convex lens, a total reflection prism, an upper deflection The optical wedge (1), the lower deflecting optical wedge (2), the upper plate of the parallel plate group (3), the lower plate of the parallel plate group (4), and the focusing convex lens (5) are sequentially arranged on the output optical path of the femtosecond laser; The module controls the femtosecond laser, the beam deflection control module controls the upper deflection wedge (1) and the lower deflection wedge (2) of the deflection wedge group, the beam translation control module controls the upper plate (3) of the parallel plate group and the lower plate of the parallel plate group The flat panel (4); the laser control module, the beam deflection control module, and the beam translation control module are connected to the cooperative control system through data lines, and the cooperative control system is connected to the industrial computer through data lines; Specifically include the following steps: 1) The trajectory of the femtosecond laser beam is accurately controlled. The beam emitted by the femtosecond laser in the scanning system first passes through the beam expander to expand and collimate the beam, and then passes through the total reflection prism to reach the upper deflection wedge of the deflection wedge group (1) , sequentially passing through the lower deflecting wedge (2) of the deflecting wedge group, the deflecting wedge group can realize precise deflection of the light beam under the condition of controlling the precision of the rotation angle; 2) The deflected beam enters the upper plate (3) of the parallel plate group and the lower plate (4) of the parallel plate group, and the difference between the angle between the upper plate (3) of the parallel plate group and the lower plate (4) of the parallel plate group can be Accurately realize the translation distance of the beam; 3) The translated light beam enters the focusing convex lens (5), and the focused light beam reaches the workpiece. Under the comprehensive control of the industrial computer, the scanning distribution, motor speed, laser power, and taper parameters are precisely controlled to perform precise processing. 2. A scanning method for accurate and controllable femtosecond laser beam trajectory according to claim 1, characterized in that: the wedge angle of the upper deflection wedge (1) and the lower deflection wedge (2) is ≤ 5°, and there is a gas gap between the upper deflecting wedge (1) and the lower deflecting wedge (2), the upper deflecting wedge (1) and the lower deflecting wedge (2) rotate relatively around the optical axis, and the beam passes through the wedge Finally, an included angle will be formed with the optical axis, which is equal to the combined angle of the two deflecting wedges; when the direction of the wedge angle of the two deflecting wedges is opposite, the resulting deflection angle is 0°, and the effect of the double wedge It is equivalent to a parallel flat plate, and the light only produces a small offset of the upper and lower positions; when the direction of the wedge angle of the two deflecting wedges is the same, that is, the relative rotation of the two deflecting wedges is 180°, the maximum deflection angle generated at this time is one The optical wedge produces twice the deflection angle; if the relative rotation angle of the two optical wedges is 360°, the reverse maximum deflection angle will be produced. 3. A kind of scanning method for accurate and controllable femtosecond laser beam trajectory according to claim 1, it is characterized in that: described parallel flat plate group is made up of two equal-thick parallel flat plates, when there is a certain angle The light beam is incident on the parallel plate, by driving the motor to control the relative rotation angle of the two parallel plates, the outgoing beam will have a displacement offset relative to the incident beam; when the parallel plate has a certain inclination angle, when the two plates are parallel, the offset Maximum; when the two plates are complementary and the translation amount is 0, when there is mutual rotation between the two plates, within the range of 0° to 90°, the plate offset will increase with the increase of the relative rotation angle. 4. A scanning method for accurate and controllable femtosecond laser beam trajectory according to claim 1, characterized in that: the beam emitted by the laser first passes through a beam expander to expand and collimate the beam, and then passes through the deflected beam After the wedge group forms a small angle with the optical axis, and then passes through the parallel plate group to produce a certain translation, and then passes through the focusing lens to focus on the focal plane that is a small distance away from the optical axis; when the deflection wedge group and the parallel plate group With synchronous high-speed rotation, a circular trajectory will be formed on the focal plane. By changing the relative deflection angle of the optical wedge and the relative rotation angle of the parallel plate in real time, the processing of large depth-to-diameter ratio and controllable taper microholes can be realized. 5. A kind of scanning method that is used for the accurate and controllable scanning method of femtosecond laser beam trajectory according to claim 1, is characterized in that: by changing the inclination angle of parallel plate and horizontal direction to adjust beam offset; by changing deflection wedge The synthetic angle and the focal length of the focusing lens are used to adjust the processing aperture; the taper of the processing hole is adjusted by changing the total thickness of the parallel plate, the beam diameter, the distance from the lower wedge to the focusing lens, and the focal length of the focusing lens.

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