Ultrafast laser pulse welding system

Abstract

The utility model relates to an ultrafast laser pulse welding system. The ultra-fast laser pulse welding system comprises a laser source, a first structure light field welding device and a second structure light field welding device, the space shaping module is configured to convert the first structured light field laser pulse into a second structured light field laser pulse; and the scanning galvanometer is configured to adjust the emitting direction of the second structured light field laser pulses so as to utilize the second structured light field laser pulses with the same parameters to conduct repeated scanning on the interface of the first material and the second material according to the planned welding track, enabling the first material and the second material to at least reach an optical contact condition through at least one scanning performed in advance; and the first material and the second material are fused through at least one scanning performed later so as to generate a welding point in a preset shape. The method is high in welding quality, can be applied to precise bonding of electronic components and the like, and is suitable for industrialization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser welding, in particular to a kind of ultrafast laser pulse welding system. BACKGROUND

[0002] Laser welding is a kind of technology using high-energy laser beam to connect materials, which is widely used in automobile, aerospace, electronics and medical devices and other fields. Compared with traditional welding methods, its main advantages include high precision, high speed and low heat affected zone, which can realize precise welding and connection of small parts.

[0003] Laser welding can be divided into traditional laser welding and ultrafast pulse laser welding. Among them, the light source of traditional laser welding is mainly continuous wave laser, nanosecond or picosecond laser, and the principle is to use the principle of rapid heating of laser to heat the welding surface to make it melt and connect together, usually welding on the edge, for example, its function is similar to traditional electric arc welding. Unlike traditional laser welding, the principle of ultrafast pulse laser welding is to rely on the instantaneous energy deposition of ultrafast pulse laser to make the material at the interface undergo rapid nonlinear absorption, local melting and solidification, so as to realize precise connection, usually acting on the contact surface of the material, with strong bonding force and little damage to the part outside the welding area.

[0004] However, ultrafast pulse laser welding is more sensitive to the characteristics of materials (such as reflectivity and absorptivity), and has higher requirements for the quality of material surface. Different welding effects may be caused by inconsistent sample states, affecting the welding quality, and thus encountering a bottleneck in mass production.

[0005] At present, in order to improve the welding quality, although there are some designs of ultrafast pulse laser welding methods, for example, when welding at the interface of glass and metal, a lower energy ultrafast pulse laser is used for pre-scanning to only make the underlying metal ablate and splash, and the glass above should not be damaged to the threshold to avoid nonlinear effect and melting, and then a higher energy ultrafast pulse laser is used for welding. However, due to the step-by-step scanning of pre-scanning and formal scanning, the steps are complicated, and the heating time of the underlying metal at high temperature may be increased, which may affect the quality of welding marks, such as may cause the welding mark to be wider, so it cannot be applied to welding occasions that require high-precision fine welding marks and cannot tolerate long-time high-temperature heating, such as not suitable for use in the bonding of electronic components. INVENTION CONTENTS

[0006] Therefore, the embodiments of the present application provide an ultrafast laser pulse welding system to solve at least one problem in the background art.

[0007] The embodiments of the present application provide an ultrafast laser pulse welding system, which comprises:

[0008] a laser source configured to output a first structured light field laser pulse; the first structured light field laser pulse has a light intensity distribution law that the light intensity at the center of the light beam is the highest and decreases towards the edge of the light spot according to a first variation trend;

[0009] a spatial shaping module configured to transform the first structured light field laser pulse into a second structured light field laser pulse; the second structured light field laser pulse has a light intensity distribution law that the light intensity in at least one designated region in the cross section of the light beam remains constant and decreases towards the edge of the light spot according to a second variation trend; the second variation trend is steeper than the first variation trend; and

[0010] a scanning galvanometer configured to adjust the emission direction of the second structured light field laser pulse, so as to repeatedly scan according to a planned welding track at the interface between the first material and the second material with the second structured light field laser pulse of the same parameters, so that at least one of the scans performed first realizes that the first material and the second material at least reach the optical contact condition; and at least one of the scans performed later realizes that the first material and the second material intermingle to produce a preset shape welding point.

[0011] In an optional embodiment, the laser source includes at least one of the following: a femtosecond laser source; a picosecond laser source; a nanosecond laser source.

[0012] In an optional embodiment, the second structured light field laser pulse includes at least one of the following: a Bessel beam; a flat-top beam.

[0013] In an optional embodiment, the parameters of the second structured light field laser pulse include at least one of the following: average power; peak power; pulse energy; pulse repetition rate; pulse width; pulse train mode.

[0014] In an optional embodiment, the spatial shaping module includes at least one of the following: a diffractive optical component; a spatial phase modulator.

[0015] In an optional embodiment, the ultrafast laser pulse welding system further includes:

[0016] an external regulator configured to compress the first structured light field laser pulse to obtain an extremely short pulse.

[0017] In an optional embodiment, the external regulator includes at least one of the following: a frequency doubler; an optical parametric amplifier; a multiple crystal solid-state frequency expansion module; a multiple cavity body frequency expansion compression module; a hollow optical fiber frequency expansion module.

[0018] In an optional embodiment, the ultrafast laser pulse welding system further includes:

[0019] An electrically controlled translation stage configured to control movement of the first material and the second material to implement the multiple repeated scans.

[0020] The technical scheme provided by the embodiments of the present application has the beneficial effects that: the second structured light field laser pulse with the same parameters in multiple scans simplifies the welding step, and through multiple welding scans on the same path, the bonding force, reliability and stability of the ultrafast laser welding can be greatly improved. Unlike single scan welding, multiple scan welding completes the entire welding process in two parts. First, the material is melted to ensure that the gap between the two materials is filled and the optical contact condition is met, so that the welding mark can be controlled within the preset high-precision range, improving the welding mark quality. Then, welding is performed, which can overcome the defects of micro-cracks and pores that are prone to occur during welding, and shorten the welding time. It can be applied to precision bonding of electronic components and other precision bonding, solve the problem of poor welding effect caused by uneven material surface, reduce the quality requirements of ultrafast laser welding on samples, and ensure consistent welding effect of different samples. It can greatly improve the laser welding effect and further improve the industrialization possibility.

[0021] Some of the aspects and advantages of the embodiments of the present application will be given in the following description, some will become apparent from the following description, or will be understood by those skilled in the art through practice of the embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings incorporated in and forming a part of the specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application. In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings according to these drawings without any creative effort. These drawings and the written description are not intended to limit the scope of the present application in any way, but to explain the concept of the present application to those skilled in the art by referring to specific embodiments. In the drawings:

[0023] Figure 1 A schematic diagram of a principle block diagram of a specific example of an ultrafast laser pulse welding system in the embodiments of the present application;

[0024] Figure 2 A reaction change diagram of a specific example of single laser welding scan using first structured light field laser pulse in related art;

[0025] Figure 3 A reaction change diagram of a specific example of twice laser welding scan using second structured light field laser pulse in the embodiments of the present application;

[0026] Figure 4 a schematic diagram of a principle block for another specific example of the ultrafast laser pulse welding system in the embodiments of the present application;

[0027] Figure 5 a schematic diagram of a principle block for another specific example of the ultrafast laser pulse welding system in the embodiments of the present application. DETAILED DESCRIPTION

[0028] In order to make the technical solutions and beneficial effects of the present application more obvious and easy to understand, the following will be described in detail by way of listing specific embodiments. The drawings are not necessarily drawn to scale, and local features can be enlarged or reduced to more clearly show the details of local features; unless otherwise defined, the technical and scientific terms used herein have the same meaning as the technical and scientific terms in the technical field to which the present application belongs.

[0029] The embodiments of the present application are not exhaustive, but only illustrate some embodiments, and are not specific limitations on the protection scope of the present application. In the case of no contradiction, each step in an embodiment can be implemented as an independent embodiment, and the steps can be combined arbitrarily, for example, the scheme after removing some steps in an embodiment can also be implemented as an independent embodiment, and the order of the steps in an embodiment can be exchanged arbitrarily, in addition, the optional implementation manners in an embodiment can be combined arbitrarily; in addition, the embodiments can be combined arbitrarily, for example, the steps of different embodiments or part of the steps of different embodiments can be combined arbitrarily, an embodiment can be combined with the optional implementation manners of other embodiments arbitrarily.

[0030] In the embodiments of the present application, the terms and / or descriptions of the embodiments are consistent and can be referred to each other if there is no special description and logical conflict, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0031] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and not as a limitation on the present application.

[0032] In the embodiments of the present application, unless otherwise stated, the elements expressed in singular form, such as "one", "a", "the", "above", "said", "preceding", "this" and the like, can represent "one and only one", or "one or more", "at least one" and the like. For example, in the case of using articles such as "a", "an", "the" and the like in English, the noun after the article can be understood as singular expression, or as plural expression.

[0033] In the embodiments of the present application, "multiple" refers to two or more.

[0034] In some embodiments, the terms "at least one of," "one or more of," "a plurality of," "multiple," and the like can be used interchangeably.

[0035] In the embodiments of the present application, the prefix words "first", "second", and the like are merely used to distinguish different description objects, and do not constitute a limitation on the position, order, priority, value or content of the description objects. The description of the description objects should refer to the description in the context of the claims or embodiments, and should not constitute an additional limitation because of the use of the prefix words. For example, the value of the description object is not limited by the ordinal number, and can be one or more. For example, the value of "the first device" can be one or more. In addition, the objects modified by different prefix words can be the same or different, for example, the description object is "device", and "the first device" and "the second device" can be the same device or different devices, and the types thereof can be the same or different.

[0036] In some embodiments, the term "connection" can mean that there is an electrical signal or data transmission between the connected end and the connected end, which can be understood as "electrical connection", "communication connection" and the like. The "connection" can be a direct connection between two components, or an indirect connection established through other components, or a communication between two components, or any other possible connection form.

[0037] Pulse width: generally refers to the duration of the pulse in time, usually the width at 50% of the pulse energy intensity is taken as the pulse width, and the unit is second.

[0038] Pulse repetition rate: refers to the number of pulses output per second, and the unit is hertz.

[0039] Pulse energy: the energy of each pulse, and the unit is joule.

[0040] Average power: the pulse energy multiplied by the pulse repetition rate, which is the output energy per second of the pulse, and the unit is watt (W).

[0041] Peak power: the pulse energy divided by the pulse width, which is the instantaneous output energy of the pulse, and the unit is watt (W).

[0042] Bandwidth: the spectral width contained in a pulse laser, and the unit is nanometer.

[0043] Spectral broadening: through optical nonlinear effect, the bandwidth of the pulse is increased.

[0044] Burst mode: The burst mode in the laser is an operation mode in which the laser emits light pulses in the form of fast consecutive pulse groups or bursts, rather than individual continuous pulses.

[0045] The embodiment of the present application provides a kind of ultrafast laser pulse welding system, Figure 1 The principle block diagram of a specific example of the ultrafast laser pulse welding system in the embodiment of the present application is shown.The ultrafast laser pulse welding system includes:

[0046] The laser source 10 is configured to output the first structured light field laser pulse L1;The light intensity distribution law of the first structured light field laser pulse L1 is that the light intensity of the beam center point is the highest, and decreases to the spot edge according to the first change trend;

[0047] The spatial shaping module 20 is configured to convert the first structured light field laser pulse L1 into the second structured light field laser pulse L2;The light intensity distribution law of the second structured light field laser pulse L2 is that the light intensity in at least one set region in the beam cross section remains constant, and decreases to the spot edge according to the second change trend;The second change trend is more steep than the first change trend;And

[0048] The scanning galvanometer 30 is configured to adjust the emission direction of the second structured light field laser pulse L2, so as to use the second structured light field laser pulse L2 with the same parameters to repeatedly scan (N≥2, N is the number of scans) at the planned welding track at the interface IF of the first material A1 and the second material A2, so that at least one scan in the first scan realizes that the first material A1 and the second material A2 at least reach the optical contact condition;And at least one scan in the latter realizes that the first material A1 and the second material A2 intermingle to produce a preset shape welding point.

[0049] In the embodiment of the present application, the structured light field of laser pulse can refer to a kind of spatial light beam with set amplitude, phase, polarization distribution, coherence or with orbital angular momentum.The first structured light field laser pulse L1 and the second structured light field laser pulse L2 can both be light pulses emitted under burst mode (burst mode), or can also be other forms of light pulses.

[0050] In the exemplary embodiment, with reference to Figure 1The first structured light field laser pulse L1 is usually a Gaussian beam. However, if a Gaussian beam is directly used for welding, due to the light intensity distribution law of the Gaussian beam, the beam energy is highly concentrated at the focal point, which is easy to cause self-focusing effect, and it is easy to produce micro-cracks and pores in the welding process, and it is difficult to overcome by controlling process parameters, and the welding quality is poor.

[0051] The second structured light field laser pulse L2 can include at least one of a Bessel beam, a Top-Hat beam, and the like. The second structured light field laser pulse L2 can have a light spot with uniform light intensity distribution on the focal plane (i.e., the interface IF between the first material A1 and the second material A2), or can have two, three, four or more light spots with uniform light intensity, so that the light intensity remains constant in one or more set regions. Moreover, due to the steep light intensity trend of the second structured light field laser pulse L2, such as the spatial distribution dispersion before and after the focal plane, it is not easy to cause self-focusing effect, so that stable and sufficient material melting can be produced in the first scanning, and the optical contact condition is reached, so that the defect of easily producing micro-cracks and pores in the welding using the first structured light field laser pulse L1 can be overcome, and the gap between the first material A1 and the second material A2 is fully filled, so as to improve the welding quality, and is particularly suitable for materials that are easy to damage.

[0052] In the embodiments of the present application, the number of repeated scanning times can be set according to the actual needs of the welding material characteristics. The materials of the first material A1 and the second material A2 are not limited to the same material, and the wavelength of the laser source can penetrate the first material A1 to the interface. The welding material can include at least one of an insulator (such as glass), a semiconductor (such as a silicon wafer), a conductor (such as metal), and the like. The scanning speed and the number of repetitions can be adjusted by the scanning galvanometer 30 to meet the actual needs.

[0053] In the exemplary embodiments, the second structured light field laser pulse L2 with the same parameter condition can be used for repeated scanning welding of the same trajectory twice. Figure 2 A reaction change diagram of a specific example of single laser welding scanning using the first structured light field laser pulse in the related art is shown. Figure 3 A reaction change diagram of a specific example of twice laser welding scanning using the second structured light field laser pulse in the embodiments of the present application is shown. Referring to Figure 2 and Figure 3, single laser welding scan, a single scan can occur X1 to X3 reaction changes at the interface. X1: directly generate nonlinear effects, generate plasma, and occur self-focusing effect; X2: with the continuation of heating, avalanche effect occurs; X3: after cooling, water droplet-shaped welding points are formed. Although single beam scanning can complete welding, the floating range of the finished product bonding force is extremely large, and it cannot be ensured that each bonding is successful. Because Figure 2 In the single scanning process, first, by virtue of the characteristics of ultrafast pulses, nonlinear effects are directly generated at the interface of the material, and then by virtue of the subsequent pulse continuous heating of the same point, avalanche effect is generated, so that the upper and lower two independent interfaces are mixed together, and after cooling, raindrop-shaped welding structure is formed, and the upper and lower two samples are fixed. The premise for the smooth completion of this process is that when the avalanche effect occurs, the upper and lower two independent materials can contact each other and mix, otherwise after subsequent cooling, it will still be two independent structures, not only the welding is not completed, but even the flatness of the surface will be damaged. Then, only single scanning can easily cause the following problems: 1. Poor stability: due to the inconsistency between the flatness of the bonded material and the stability of the light source, the result of single scanning welding may cause great differences in the welding results in the track, and only a small part of the area may have completed welding, thereby resulting in poor welding effect. 2. Poor reliability: if only single scanning is performed, the consistency of the bonded material is required, otherwise the welding effect of different blocks of material cannot be ensured to be consistent, which is not suitable for application in the production of industrial products. 3. Higher requirements for material quality: if the flatness of the material itself is too poor, or the gap between the samples is too large, even if the plasma is generated by laser, it may not be able to mix with each other due to the too far distance between the two materials, and finally the welding cannot be completed, but the surface of the material is damaged.

[0054] Compared with single laser welding scanning, in the two laser welding scanning of the embodiments of the present application, in the first laser welding scanning, Y1 to Y3 reaction changes can occur at the interface. Y1: at least one of the first material A1 and the second material A2 is melted; Y2: with the continuation of heating, the melted material deforms and fills the gap and gap at the interface; Y3: after cooling, the optical contact condition is reached. In the second laser welding scanning, Z1 to Z3 reaction changes can occur at the interface. Z1: nonlinear effects are generated, plasma is generated, and self-focusing effect occurs; Z2: with the continuation of heating, avalanche effect occurs; X3: after cooling, water droplet-shaped welding points are formed.

[0055] Thus, the second structured light field laser pulse with the same parameters in multiple scans is used in the embodiment of the application to simplify the welding step, and multiple welding scans on the same path can greatly improve the bonding strength, reliability and stability of ultrafast laser welding. Unlike single scan welding, multiple scan welding completes the entire welding process in two parts. First, the material is melted to ensure that the gap between the two materials is filled and the optical contact condition is met, so that the welding mark can be controlled within the preset high-precision range, improving the welding mark quality. Then, welding is performed to overcome the defects of micro-cracks and pores that are prone to occur during welding, and shorten the welding time, which can be applied to precision bonding of electronic components and other precision bonding, solve the problem of poor welding effect caused by uneven material surface, reduce the requirements of ultrafast laser welding on sample quality, and ensure consistent welding effect of different samples, which can greatly improve the laser welding effect and further improve the industrialization possibility.

[0056] In the embodiment of the application, the shaped and parameter-adjusted light beam can be controlled by the scanning galvanometer 30 to control the speed and trajectory of the light beam on the sample (the interface IF of the first material A1 and the second material A2), but is not limited thereto, and can also use prisms, wedge-shaped lenses and other methods to adjust the direction of the light beam in space to move the light beam. The welding trajectory (trajectory pattern) can be adjusted according to the actual needs of the size and shape of the sample. The preset shape of the welding point can be drop-shaped, but is not limited thereto, and can also be spherical and the like.

[0057] In an optional embodiment, the laser source 10 includes at least one of the following: a femtosecond laser source; a picosecond laser source; a nanosecond laser source.

[0058] As a preferred embodiment, a femtosecond laser source can be used to obtain better welding effect. For example, a wavelength 1030 nm femtosecond laser source can be used, and the wavelength can be converted according to the material needs to penetrate the first material A1 to reach the interface IF.

[0059] In an optional embodiment, the parameters of the second structured light field laser pulse L2 include at least one of the following: average power; peak power; pulse energy; pulse repetition rate; pulse width; pulse train mode.

[0060] Thus, the parameters of the laser pulses can be adjusted according to the needs of the material, so as to complete and satisfy the laser welding without damaging the material and with good bonding force. The average power, peak power and pulse energy can be matched with different conditions according to different materials. The increase of the pulse repetition rate can increase the welding speed, because the number of pulses per unit length can be adjusted by the welding speed, and the increase of the repetition rate helps to increase the moving speed. The narrower the pulse width, the lower the heat effect diffusion, which can avoid the deformation or damage of the material outside the welding due to heat. The adjustment of the pulse train mode (pulse train sequence) can change the heat accumulation condition on the welding track, and the welding feasibility of some materials with high melting point can be achieved by changing the pulse train sequence.

[0061] In an optional embodiment, the spatial shaping module 20 comprises at least one of the following: a diffractive optical element (DOE); a spatial phase modulator.

[0062] In the embodiments of the present application, the spatial shaping module 20 can shape the light beam to obtain the required second structured light field laser pulse L2. The light beam shaping method can have various types of optical devices, which can be set according to actual needs. Different spot shapes can also control the welding feasibility on different materials. For example, the Gaussian beam is a commonly used light beam, but it is not suitable for welding of materials that are easy to damage. The flat-top light spot has the characteristics of not easily causing self-focusing effect and dispersed spatial distribution before and after the focal point, and is suitable for use on materials that are easy to damage.

[0063] Figure 4 A principle block diagram of another specific example of the ultrafast laser pulse welding system in the embodiments of the present application is shown. As shown in the figure, in an optional embodiment, the ultrafast laser pulse welding system further comprises:

[0064] The external adjuster 40 is configured to compress the first structured light field laser pulse L1 to obtain an extremely short pulse.

[0065] In an optional embodiment, the external adjuster 40 comprises at least one of the following: a frequency doubler; an optical parametric amplifier; a multiple crystal solid-state frequency expansion module; a multiple cavity body frequency expansion compression module; and a hollow optical fiber frequency expansion module.

[0066] Thus, before entering the machining scanning galvanometer, various nonlinear methods (such as frequency doubling, frequency tripling, optical parametric amplifiers, etc.) can be used to convert the wavelength and characteristics of the light source. For example, the output wavelength range can be 300 nm to 3000 nm, and the output pulse width can be 10 femtoseconds to 2 picoseconds. Multiple crystal solid-state expansion modules, multi-cavity expansion compression modules, or hollow fiber expansion modules can also be used to compress laser pulses to extremely short pulses (such as less than 100 femtoseconds). For example, nonlinear effects can be generated by optical crystals to increase the bandwidth of the laser; multiple pieces of sheet material with a thickness of less than 2 mm can be used as expansion media, and the size and shape of the spot can be controlled by spatial shaping to achieve nonlinear effects that can generate self-phase modulation and self-focusing effects, and a series of multiple sets of solid-state media with specific arrangement spacing can be used to form continuous expansion to compensate for the damage caused by laser intensity due to the thickness of the medium or the insufficient nonlinear expansion coefficient due to the thickness of the medium. By using multiple pieces of sheet material with a thickness of less than 2 mm as expansion media, compared to using gas as expansion media, solid media can provide more nonlinear effects and better expansion effects, and compared to using a single piece of material with a thickness of about 1 cm, using multiple pieces of sheet material can increase the pulse energy that the system can withstand, and can generate laser pulses that meet the needs of the industry.

[0067] The external regulator of the embodiment of the present application can reduce the thermal effect again to achieve more accurate control, achieve high-precision welding, and improve the quality of the weld. By delivering high energy in a very short time to form a local plasma, micron-level welding is achieved. Its cold working characteristics have almost no thermal effect, and it is suitable for fields such as microelectronics and medical devices, and can achieve high-precision, low-thermal-impact microscale welding. Therefore, the thermal effect can be more effectively and accurately controlled, and the bonding strength of the weld can be improved.

[0068] Figure 5 This is a schematic diagram of the principle block diagram of another specific example of the ultrafast laser pulse welding system in the embodiment of the present application. In an optional embodiment, as shown in Figure 5 The ultrafast laser pulse welding system further includes:

[0069] The electrically controlled translation stage 50 is configured to control the movement of the first material A1 and the second material A2 to achieve the multiple repeated scans.

[0070] In the embodiments of the present application, the electrically controlled translation stage 50 can move the sample, and the scanning galvanometer 30 can move the laser pulse irradiated on the sample, so as to realize the welding scanning of the planned welding track on the sample. That is, the multiple repeated optical scanning can be realized not only by moving the light beam by the scanning galvanometer, but also by controlling the motion platform carrying the sample to complete the same process. The motion platform is inferior to the optical scanning galvanometer in the characteristics of speed and accuracy, but can perform large-area moving scanning welding. The electrically controlled translation stage 50 can expand the scanning area and realize large-range welding scanning. The moving mode of the sample is not limited to three-axis linear movement, but can also be various spatial displacement modes such as rotation, inclination, etc.

[0071] It should be understood that the above embodiments are exemplary and are not intended to include all possible implementations included in the claims. Various modifications and changes can also be made on the basis of the above embodiments without departing from the scope of the present disclosure. Similarly, any combination of the technical features of the above embodiments can also be made to form additional embodiments of the present application which can not be explicitly described. Therefore, the above embodiments only express several implementation manners of the present application, and do not limit the protection scope of the patent of the present application.

Claims

1. An ultrafast laser pulse welding system, characterized by, The ultrafast laser pulse welding system comprises: a laser source configured to output a first structured light field laser pulse; the first structured light field laser pulse has a light intensity distribution law that the light intensity of a beam center point is the highest and decreases to a spot edge according to a first change trend; a spatial shaping module configured to convert the first structured light field laser pulse into a second structured light field laser pulse; the second structured light field laser pulse has a light intensity distribution law that the light intensity in at least one set region in a beam cross section remains constant and decreases to a spot edge according to a second change trend; the second change trend is steeper than the first change trend; and a scanning galvanometer configured to adjust an outgoing direction of the second structured light field laser pulse, so as to repeatedly scan a planned welding track at an interface between a first material and a second material by using the second structured light field laser pulse with the same parameters, so that at least one scan performed in advance realizes that the first material and the second material at least reach an optical contact condition; and at least one scan performed later realizes that the first material and the second material intermingle to generate a preset shape welding point.

2. The ultrafast laser pulse welding system of claim 1, wherein, The laser source comprises at least one of the following: a femtosecond laser source; a picosecond laser source; and a nanosecond laser source.

3. The ultrafast laser pulse welding system of claim 1, wherein, The second structured light field laser pulse comprises at least one of the following: a Bessel beam; and a flat-top beam.

4. The ultrafast laser pulse welding system of claim 1, wherein, Parameters of the second structured light field laser pulse comprise at least one of the following: average power; peak power; pulse energy; pulse repetition rate; pulse width; and pulse train mode.

5. The ultrafast laser pulse welding system of claim 1, wherein, The spatial shaping module comprises at least one of the following: a diffractive optical component; and a spatial phase modulator.

6. The ultrafast laser pulse welding system of claim 1, wherein, The ultrafast laser pulse welding system further comprises: an external adjuster configured to compress the first structured light field laser pulse to obtain an extremely short pulse.

7. The ultrafast laser pulse welding system of claim 6, wherein, The external adjuster comprises at least one of the following: a frequency doubler; an optical parametric amplifier; a multiple-crystal solid-state frequency expansion module; a multiple-cavity frequency expansion compression module; and a hollow optical fiber frequency expansion module.

8. The ultrafast laser pulse welding system of any of claims 1-7, wherein, The ultrafast laser pulse welding system further comprises: an electrically controlled translation stage configured to control movement of the first material and the second material to realize the repeated scanning.

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