A laser processing head, a laser processing device, and a system thereof

Abstract

The application relates to the technical field of laser processing, and provides a laser processing head, a laser processing device and a system thereof, the laser processing head comprising coaxially arranged first, second and third lenses, wherein the vertical distance z from any point on the laser incidence surface (vertex curvature radius 70mm<=R1<=110mm) and the laser emission surface (vertex curvature radius -70mm<=R2<=-50mm) of the first lens to the vertex along the optical axis direction satisfies a preset formula; and the incident laser passes through the first, second and third lenses in sequence to form a processing beam acting on a workpiece to be processed. The laser processing head provided by the application can obtain a processing beam with an extremely small spot diameter, can realize higher focusing efficiency and energy density distribution, and can provide a wider focal point position range for processing due to the longer effective working area of the processing beam compared with a conventional beam, thereby greatly improving the processing efficiency in batch production.

Description

Technical Field

[0001] This application relates to the field of laser processing technology, and in particular to a laser processing head, laser processing device and system thereof. Background Technology

[0002] Laser processing is a processing technology that utilizes the interaction between a laser beam and matter to perform surface or internal treatments such as cutting and welding. Currently, laser processing, as an advanced material processing method, is widely used in fields such as electronics manufacturing, automotive industry, aerospace, and medical devices. In existing laser processing technologies, conventional laser processing heads mostly use a combination of spherical lenses to achieve beam collimation and focusing.

[0003] However, as modern manufacturing demands higher processing precision and efficiency, traditional solutions are gradually revealing their shortcomings. Spherical lenses, affected by aberrations, make it difficult to further reduce the diameter of the converged processing beam spot, resulting in insufficient energy density and impacting processing efficiency and quality. Furthermore, their narrow focus adjustment range necessitates frequent adjustments to the processing head's focus position during batch processing, further limiting efficiency.

[0004] Therefore, optimizing the optical structure to achieve a processing beam with an extremely small spot size and a long effective working area, thereby improving the energy density and processing efficiency of the output laser, has become a key issue that urgently needs to be addressed in the field of laser processing. Utility Model Content

[0005] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a laser processing head, a laser processing device and system thereof, which can form a processing beam with an extremely small spot size and a long effective working area, so as to solve the technical problems of low laser energy density and low processing efficiency of traditional laser processing heads.

[0006] To achieve the above and other related objectives, this application provides a laser processing head, including a first lens, a second lens, and a third lens arranged coaxially along the transmission direction of the incident laser. The perpendicular distance z from any point on the laser incident surface and the laser exit surface of the first lens to its vertex along the optical axis satisfies the following formula:

[0007] in, or r is the radial distance from any point on the laser incident surface and the laser exit surface to the optical axis, and 0mm≤r≤40mm; k is a correction coefficient, 0.8≤k≤1.2; a2, a3, a4, a5, a6 are all conic coefficients of the laser incident surface or the laser exit surface, specifically... ≤a2≤ , ≤a3≤ , ≤a4≤ , ≤a5≤ , ≤a6≤ ; The vertex radius of curvature of the laser incident surface of the first lens is 70mm≤R1≤110mm, and the vertex radius of curvature of the laser exit surface of the first lens is -70mm≤R2≤-50mm. The incident laser beam is formed into a narrow beam after passing through the first lens. The second lens is used to collimate the narrow beam. The third lens is used to focus the collimated beam output from the second lens to form a processing beam acting on the workpiece to be processed.

[0008] As a preferred embodiment, the second lens has a first curved surface and a second curved surface, the first curved surface facing the first lens and the second curved surface facing the third lens, the radius of curvature of the first curved surface being -750mm≤R3≤-610mm and the radius of curvature of the second curved surface being 60mm≤R4≤90mm.

[0009] As a preferred embodiment, the distance between the center of the second lens and the center of the first lens is 30mm≤l≤45mm.

[0010] As a preferred embodiment, the third lens is a biconvex lens or a positive meniscus lens.

[0011] As a preferred embodiment, the waist diameter of the processing beam is less than 0.21 mm.

[0012] As a preferred embodiment, the center thickness of the first lens is 3mm≤d1≤20mm.

[0013] As a preferred embodiment, the center thickness of the second lens is 3mm≤d2≤20mm.

[0014] As a preferred embodiment, a protective mirror is also provided at the output end of the third lens.

[0015] As another aspect of this application, a laser processing apparatus is also proposed, comprising the laser processing head described in any of the preceding claims.

[0016] As another aspect of this application, a laser processing system is also proposed, including the laser processing apparatus described above.

[0017] Compared to existing technologies, the laser processing head provided in this application can be used in fields including but not limited to laser cutting and laser welding. The laser processing head includes a first lens, a second lens, and a third lens arranged coaxially along the transmission direction of the incident laser. The perpendicular distance z from any point on the laser incident surface and the laser exit surface of the first lens to its vertex along the optical axis satisfies the following formula:

[0018] in, or ; r is the radial distance from any point on the laser incident surface and the laser exit surface to the optical axis, and 0 mm ≤ r ≤ 40 mm; k is a correction factor, 0.8 ≤ k ≤ 1.2; a2, a3, a4, a5, and a6 are all conic coefficients of the laser incident or laser exit surface, specifically, ≤a2≤ , ≤a3≤ , ≤a4≤ , ≤a5≤ , ≤a6≤ ; The vertex radius of curvature of the laser incident surface of the first lens is 70mm≤R1≤110mm, and the vertex radius of curvature of the laser exit surface of the first lens is -70mm≤R2≤-50mm. After the incident laser passes through the first lens, it forms a beam-contracted beam. The second lens is used to collimate the beam-contracted beam, and the third lens is used to focus the collimated beam output from the second lens to form a processing beam acting on the workpiece to be processed.

[0019] The laser processing head of this application can obtain a processing beam with an extremely small spot diameter, enabling higher focusing efficiency and energy density distribution. Specifically: 1. For example, when processing a certain material, existing technologies have a relatively wide output laser beam profile, and the laser beam's longitudinal direction ( Figure 3 The effective working area in the x-coordinate direction is relatively short, and the number of laser spots that can be used for processing is small within a predetermined length range; while the laser beam profile of this application is extremely narrow, and the laser beam longitudinal ( Figure 3 The effective working area in the x-coordinate direction is relatively long, and within the same predetermined length range, there are many laser spots that can be used for processing. This provides more options for focusing during processing, thus the focusing efficiency is higher, which greatly improves the processing efficiency on the production line.

[0020] 2. Compared with the prior art, the laser filament solution of this application has higher energy distribution density, which improves processing efficiency and allows for faster completion of processing tasks. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0022] Figure 1 This is a schematic diagram of the structure of the laser processing head in the embodiments of this application; Figure 2 A schematic diagram showing the energy density profiles of three laser beams used for processing; Figure 3 This is a schematic line showing the distribution of the spot radius of the laser processing head output beam in some embodiments of this application; Figure 4 This is a partial shape of the laser emitting surface in one embodiment of this application.

[0023] Among them, 11 is the first lens; 12 is the second lens; 13 is the third lens; and 14 is the protective lens. Detailed Implementation

[0024] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0025] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0026] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0028] Definitions: In this application, the sign of the radius of curvature of each lens is determined according to the following rules: For the front surface of the lens (the surface facing the incident laser), with the vertex of the surface as the origin, if the surface is convex outward, the radius of curvature is positive; if the surface is concave inward, the radius of curvature is negative. For the rear surface of the lens (the surface away from the incident laser and facing the exit direction), with the vertex of the surface as the origin, if the surface is concave inward, the radius of curvature is positive; if the surface is convex outward, the radius of curvature is negative.

[0029] This application provides a laser processing head; please refer to... Figure 1 The laser processing head includes a first lens 11, a second lens 12, and a third lens 13 arranged coaxially along the transmission direction of the incident laser. One of the laser incident surface and the laser exit surface of the first lens 11 is an aspherical surface. In the embodiments of this application, the vertex radius of curvature of the laser incident surface is 70mm ≤ R1 ≤ 110mm, and the vertex radius of curvature of the laser exit surface is -70mm ≤ R2 ≤ -50mm.

[0030] Specifically, when the laser incident surface of the first lens 11 is spherical and the laser exit surface is aspherical, the radius of curvature of the laser incident surface is 70mm≤R1≤110mm, and the vertex radius of curvature of the laser exit surface is -70mm≤R2≤-50mm.

[0031] When the laser incident surface of the first lens 11 is an aspherical surface and the laser exit surface is an aspherical surface, the radius of curvature of the laser incident surface is 70mm≤R1≤110mm, and the vertex radius of curvature of the laser exit surface is -70mm≤R2≤-50mm.

[0032] It is understandable that in both of the above cases, the output of the first lens 11 is a narrow beam with a more concentrated energy distribution, which is beneficial to improving the processing quality and accuracy.

[0033] Existing laser processing heads typically employ double spherical lenses to shape the laser beam. Due to the inherent optical characteristics of spherical lenses, aberrations inevitably occur when the two sets of spherical lenses are combined. This results in a larger focused spot diameter and dispersed energy density after the shaped beam, leading to poor focusing performance. This application, however, changes the existing double spherical lens design by setting one of the laser incident and exit surfaces of the first lens 11 as an aspherical surface. This allows the beam to be further compressed after exiting through the first lens 1, while reducing the influence of aberrations, resulting in a more concentrated energy distribution in the compressed beam.

[0034] In the embodiments of this application, the perpendicular distance z from any point on the laser incident surface and the laser exit surface of the first lens 11 to its vertex along the optical axis satisfies the following formula:

[0035] in, or ; r is the radial distance from any point on the laser incident surface and the laser exit surface to the optical axis, and 0 mm ≤ r ≤ 40 mm; k is a correction factor, 0.8 ≤ k ≤ 1.2; a2, a3, a4, a5, and a6 are all conic coefficients of the laser incident or laser exit surface, specifically, ≤a2≤ , ≤a3≤ , ≤a4≤ , ≤a5≤ , ≤a6≤ It can be understood that the formula and equation are obtained by establishing a coordinate system with the vertex of the laser incident surface or the laser exit surface as the origin, the optical axis (i.e., the sagittal direction) of the first lens as the vertical axis, and the radial direction (i.e., the direction perpendicular to the optical axis) of the first lens as the horizontal axis.

[0036] For example, the perpendicular distance z from any point on the laser incident surface in the first lens 11 to its vertex along the optical axis satisfies the above equation, then Furthermore, the above equations are derived by establishing a coordinate system with the vertex of the laser incident surface as the origin, the optical axis (i.e., the sagittal direction) of the first lens as the vertical axis, and the radial direction (i.e., the direction perpendicular to the optical axis) of the first lens as the horizontal axis; the perpendicular distance z from any point on the laser exit surface of the first lens 11 to its vertex along the optical axis satisfies the above equations, then The above equations are obtained by establishing a coordinate system with the vertex of the laser emission surface as the origin, the optical axis (i.e., the height direction) of the first lens as the vertical axis, and the radial direction (i.e., the direction perpendicular to the optical axis) of the first lens as the horizontal axis.

[0037] Please refer to Figure 4 again. Figure 4 In Embodiment 1 of this application, the laser emission surface of the first lens is set to any point that satisfies the above equation. Substituting the specific parameters of the aspherical surface of the first lens (correction coefficient k=1, ...) R² = -50, conic coefficient a² = a3= a4= a5= a6= The aspherical surface elevation curve on the laser exit surface of the first lens is obtained by subtracting values ​​for the radial distance *r*. This curve has its origin at the vertex of the aspherical surface of the first lens. The horizontal axis corresponds to the radial direction of the first lens (i.e., the direction perpendicular to the optical axis), representing the radial distance *r* from any point on the laser incident / exit surface to the optical axis; the vertical axis corresponds to the optical axis direction, representing the perpendicular distance *z* from that point to the vertex along the optical axis direction. This verifies that substituting the aspherical surface parameters into the above formula can generate the expected surface shape, thereby outputting a more concentrated beam with energy distribution, which is beneficial for improving processing quality and accuracy. It can be understood that... Figure 4 Only a portion of the shape of the laser emission surface is shown; its complete shape can be obtained by mirroring the curve shown in the figure along the vertical axis.

[0038] In this application, the incident laser beam is formed into a narrow beam after passing through the first lens 11, the second lens 12 is used to collimate the narrow beam, and the third lens 13 is used to focus the collimated beam output from the second lens 12 to form a processing beam acting on the workpiece to be processed.

[0039] Compared to existing technologies, the laser processing head of this application can obtain a processing beam with an extremely small spot diameter, achieving higher focusing efficiency and energy density distribution. Because this processing beam has a longer effective working area than conventional beams, it provides a wider range of focal positions for processing, significantly improving processing efficiency in mass production.

[0040] Please continue to refer to Figure 1 The second lens 12 has a first curved surface and a second curved surface. The first curved surface faces the first lens 11, and the second curved surface faces the third lens 13. The radius of curvature of the first curved surface is -750mm≤R3≤-610mm, and the radius of curvature of the second curved surface is 60mm≤R4≤90mm. According to the positive and negative rules of lens curvature defined in this application, the first curved surface of the second lens 12 is concave inward (the front surface is concave), which can adapt to the converging characteristics of the beam output by the first lens 11. The second curved surface is also concave inward (the rear surface is concave). By matching the concave contour with the first curved surface, precise collimation of the beam can be achieved.

[0041] In one embodiment, the lens is made of fused silica, and its refractive index n varies for different wavelengths of incident laser light. Taking a lens with a refractive index n = 1.45 as an example, the technical solution of this application will be further illustrated through a specific optical design embodiment.

[0042] For the first lens, let n=1.45, R1=90mm, R2=-60mm, d=10mm, and substitute into the formula for the focal length of a thick lens:

[0043] The final result is f≈81.7mm, which means that the first lens is a positive lens with a certain focusing ability, which can compress the diverging incident laser into a narrow beam (the beam diameter is reduced).

[0044] For the second lens, let n=1.45, R3=-680mm, R4=75mm, d=5mm, and substitute into the formula for the focal length of a thick lens:

[0045] Finally, f≈-150mm is obtained, that is, the second lens 12 is a negative lens, which can compensate for the divergence of the converged beam. By designing a reasonable lens spacing, the divergence compensation amount can be matched with the convergence trend of the lens, thereby collimating the converged beam into parallel light.

[0046] It should be noted that the scheme also holds true when the radius of curvature of the first lens 11 is taken as the endpoint value. For example, when R1 = 70mm, combined with other parameters, the first lens 11 is still a positive lens with converging ability, which can compress the incident laser into a narrow beam; when R1 = 110mm, under the same parameters, the positive lens characteristics of the first lens 11 remain unchanged, the converging function is still stable, and the beam narrowing effect can meet the requirements of the subsequent optical path. For the second lens 12, when R3=-750mm, its negative lens properties and divergence compensation effect are not affected when combined with other parameters; when R3=-610mm, under the same conditions, the collimation function of the second lens 12 can still function normally, and can stably collimate the beam into parallel light.

[0047] In this application, when the radius of curvature of the first lens 11 and / or the second lens 12 is taken as the endpoint value, the beam-contraction capability of the first lens 11 and the collimation function of the second lens 12 remain stable.

[0048] In some embodiments, the distance between the center of the second lens 12 and the center of the first lens 11 is 30mm ≤ l ≤ 45mm. Specifically, when the distance between them is l = 38mm, in conjunction with the above specific embodiments, the positional relationship between the image-side focal point of the first lens 11 and the object-side focal point of the second lens 12 is as follows: the distance from the image-side focal point of the first lens 11 to the left surface of the second lens 12 is 81.7 + 38 - 10 = 109.7mm (10 is the thickness of the first lens 11). This distance is less than the 150mm distance from the object-side focal point of the second lens to the left surface, meaning that the convergent beam output by the first lens 11 has not yet reached its own image-side focal point when it reaches the second lens 12, and is in an incompletely converged state. At this time, the second lens performs divergence compensation on the convergent beam, which precisely cancels the convergence trend of the beam, and finally forms parallel light.

[0049] It is understandable that when the lens spacing is taken as the endpoint value l=30mm, the distance from the image-side focal point of the first lens 11 to the left surface of the second lens 12 is 81.7+30-10=101.7mm. This distance is still less than the distance from the object-side focal point of the second lens 12 to the left surface of 150mm, and the beam is in a state of incomplete convergence. The divergence compensation effect of the second lens 12 further counteracts the convergence tendency of the beam, and finally outputs parallel light.

[0050] When the lens spacing is taken as the other endpoint value l=45mm, the distance from the image-side focal point of the first lens 11 to the left surface of the second lens 12 is 81.7+45-10=116.7mm, which is also less than 150mm, and the beam is still not fully converged. The second lens 12 can still form stable parallel light through appropriate divergence compensation.

[0051] Therefore, it can be seen that within the entire range of 30mm≤l≤45mm and at the endpoint values, the lens group design of this application can achieve a stable conversion from a beam-contracted beam to parallel light through the synergistic effect of the first lens 11 and the second lens 12. The effectiveness and stability of the solution of this application are not affected by the endpoint values ​​of the distance between the first lens 11 and the second lens 12.

[0052] In the embodiments of this application, the center thickness of the first lens 11 is 3mm ≤ d1 ≤ 20mm; the center thickness of the second lens 12 is 3mm ≤ d2 ≤ 20mm. In actual design, the thickness can be flexibly adjusted within this range according to the specific processing requirements. It can be understood that a minimum thickness of 3mm can meet the compact installation requirements of the lens within the laser processing head, avoiding an overly bulky overall structure due to excessive thickness; while a maximum thickness of 20mm ensures that the lens has sufficient mechanical strength, preventing deformation due to external forces or temperature changes during long-term use, thus ensuring the stability of the optical path.

[0053] Alternatively, in order to cooperate with the first lens 11 and the second lens 12, the third lens 13 provided in this embodiment is a biconvex spherical lens or a positive meniscus lens, so as to minimize the cost of the system and provide excellent focusing effect.

[0054] In other embodiments, the first lens 11 and its end cap can be an integral design. In a conventional split design, the end cap serves as the optical interface before the laser enters the first lens, mainly used to expand the laser beam to reduce the direct impact of high-power laser on the lens surface. With an integral design, the first lens and the end cap share a continuous optical surface transition, which helps to reduce optical loss and improve energy utilization. At the same time, it can also achieve other beneficial effects that the laser processing head originally had in this application.

[0055] Please refer to again Figure 2 , Figure 2 The diagrams show the energy density profiles of three laser beams used for processing. The left image shows the profile of a conventional laser beam, clearly indicating a larger area on the top and bottom edges. The right image shows the profile of the laser beam (laser filament) of this application. This laser beam avoids the problem of a large area on the top and bottom edges, exhibiting a more reasonable overall area distribution, higher energy density compared to conventional laser beams, and a more uniform spot radius distribution along the laser transmission direction. The higher energy density facilitates faster laser processing. The middle image shows a multi-focal laser beam from the prior art. While this beam improves energy density and spot radius distribution (though not as drastically as the change in spot radius of a conventional beam), it still falls short of meeting the requirements for rapid laser processing. Furthermore... Figure 2 The effective working area is also shown (indicated by dashed lines). It can be seen that the effective working area of ​​the conventional beam on the left is the shortest, followed by the multifocal beam in the middle, and the effective working area of ​​the laser filament beam on the right (the solution of this application) is the longest. The laser beam energy density of this effective working area of ​​the laser filament beam on the right is relatively high compared with the conventional beam, which meets the laser energy required for rapid processing.

[0056] It is understood that by employing the laser processing head of this application, the effective working area of ​​the final output processing beam is significantly optimized. Through an innovative optical path design—namely, using the aspherical exit surface of the first lens to optimize the beam energy distribution, the second lens to extend the parallel beam and ensure transmission stability, and the third lens to focus and form the effective working area—the energy distribution pattern of the laser beam in the laser transmission direction is directly altered, creating a unique "laser filament" effect. When this processing head is specifically configured as a cutting head or a welding head, the "laser filament"-like output beam helps to suppress nozzle overheating. Furthermore, the effective working area is multi-focal adjustable, eliminating the need for frequent adjustments to the processing technology or even nozzle replacements during batch processing, greatly improving the convenience and stability of laser cutting or welding.

[0057] It should be noted that, in terms of energy distribution, the laser processing head of this application makes the processing beam approach the profile of an ultra-flat top beam, thereby achieving optimized energy distribution. The energy ratio at the edge of the spot is reduced, avoiding the situation where the energy density at the center of the spot is too high, thus ensuring a smooth and clean processing end face.

[0058] The following table shows the distribution of spot radius values ​​at various longitudinal positions of the output beam in this application, along with the distribution of spot radius values ​​at different longitudinal positions of the beam in conventional schemes for comparison: Specific implementation examples (spot radius / mm) 5 0.4371 0.4285 4 0.3771 0.3428 3 0.3171 0.2914 2 0.2657 0.2057 1 0.2314 0.1457 0 0.2143 0.1092 -1 0.2486 0.1543 -2 0.2828 0.2057 -3 0.3600 0.2743 -4 0.4114 0.3428 -5 0.4885 0.3600 Furthermore, the applicant's actual research and development experiments show that, using the laser beam scheme corresponding to the above specific embodiments, the processing speed is increased by more than 1.5 to 2 times compared to traditional conventional laser beams in actual processing scenarios.

[0059] Indicative, Figure 3 The changes and distribution of the beam spot diameter within a 5mm range before and after the longitudinal position of the beam are shown. Figure 3 The solid curve in the middle is the corresponding Figure 2 The left image shows a schematic diagram of the laser beam profile and spot radius distribution in a traditional conventional scheme. The dashed curve represents the corresponding... Figure 2 The right figure shows the laser beam profile and spot radius distribution of the laser filament scheme. In comparison, the spot diameter formed at the waist of the laser filament scheme is smaller than that of conventional schemes, and the entire beam is narrower and longer along the longitudinal direction (x-axis), which is beneficial for improving processing speed and quality. The horizontal dotted lines indicate the positions of multiple adjustable focal points of the laser beam; there are nine horizontal dotted lines, corresponding to nine laser spots that can be used for processing. This allows for more selection during actual focus adjustment, significantly improving adjustment efficiency. In contrast, existing technologies have far fewer usable laser spots than this application, resulting in fewer selections and lower adjustment efficiency during actual focus adjustment.

[0060] Optionally, the surfaces of the first lens 11 and the second lens 12 are coated with an anti-reflection film to improve the lens transmittance. The anti-reflection film has a preset damage resistance threshold to maintain good shaping performance even under high-power laser output conditions.

[0061] In the embodiments of this application, the beam waist diameter of the light beam emitted from the third lens 13 is less than 0.21 mm, where the beam waist diameter is the diameter of the laser spot corresponding to x=0.

[0062] The laser processing head also includes a protective mirror 14 disposed at the output end of the third lens 13. The converged processing beam passes through the protective mirror 14 and irradiates the workpiece to be processed. Both sides of the protective mirror are coated with anti-reflection films to ensure effective transmission of the processing laser (and indicator red light).

[0063] In one embodiment, when the collimated beam diameter is 3-8 mm, the protective lens 14 has a diameter of at least 10-20 mm and a thickness of 2-5 mm. The distance between the protective lens 14 and the center point of the third lens 13 is 20-40 mm, allowing sufficient space for heat dissipation while meeting installation and fixing requirements. To extend the service life of the protective lens 14 and reduce damage to it, a certain distance should also be maintained between the protective lens 14 and the workpiece to be processed. This distance is typically greater than 20 mm, thereby reducing the contamination and impact of dust and molten slag splashes on the surface of the protective lens 14.

[0064] In addition, the following explanation is required regarding the longitudinal position x of the beam, please refer to [reference]. Figure 3 The laser beam output by the laser for processing is symmetrical along the longitudinal direction of the beam, with the center of symmetry defined as the longitudinal position x=0. For the two parts where x<0 and x>0, the spot radius is symmetrically distributed about the center of symmetry. Of course, for asymmetrical laser beams, the laser beam of this application can also achieve a longer effective working area. Within a predetermined length range, compared with the prior art, more laser spots can be used for processing, providing more options for focusing during processing, thus resulting in higher focusing efficiency.

[0065] As another aspect of this application, a laser processing apparatus is also proposed for laser processing of a workpiece, the apparatus comprising a laser processing head as described in any of the above embodiments. It is understood that this laser processing apparatus is applicable to, but is not limited to, cutting and welding applications.

[0066] As another aspect of this application, a laser processing system is also proposed, the laser processing apparatus comprising the laser processing apparatus as described in any of the above embodiments.

[0067] It should be noted that the above-described laser processing head embodiments and laser processing device / system embodiments belong to the same concept. The specific implementation process can be found in the laser processing head embodiments. Furthermore, the technical features in the laser processing head embodiments are applicable to the above-described laser processing device and system embodiments, and will not be repeated here.

[0068] In summary, the laser processing head described in this application differs from the existing double-spherical lens design by setting one of the laser incident and exit surfaces of the first lens 11 as an aspherical surface. This allows the laser beam to be further compressed after passing through the first lens 1, while reducing the influence of aberrations, resulting in a more concentrated energy distribution in the compressed beam. Through the cooperation of the first lens, second lens, and third lens, the incident laser is compressed, collimated, and focused, altering the energy distribution pattern of the traditional laser beam in the transmission direction. This yields a fine processing beam with an extremely small spot diameter that can directly act on the workpiece surface, achieving higher focusing efficiency and energy density distribution. The laser processing head of this application solves the technical problems of low laser output energy density and low processing efficiency in existing technologies, which prevent rapid laser processing and improve processing efficiency, thus possessing high practical application value.

[0069] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A laser processing head, characterized in that, The system includes a first lens, a second lens, and a third lens arranged coaxially along the transmission direction of the incident laser. The perpendicular distance z from any point on the laser incident surface and the laser exit surface of the first lens to its vertex along the optical axis satisfies the following formula: ;in, or r is the radial distance from any point on the laser incident surface and the laser exit surface to the optical axis, and 0 mm ≤ r ≤ 40 mm; k is a correction factor, 0.8 ≤ k ≤ 1.2; a2, a3, a4, a5, and a6 are all conic coefficients of the laser incident surface or the laser exit surface, specifically... ≤a2≤ , ≤a3≤ , ≤a4≤ , ≤a5≤ , ≤a6≤ ; The vertex radius of curvature of the laser incident surface of the first lens is 70mm≤R1≤110mm, and the vertex radius of curvature of the laser exit surface of the first lens is -70mm≤R2≤-50mm. The incident laser beam is formed into a narrow beam after passing through the first lens. The second lens is used to collimate the narrow beam. The third lens is used to focus the collimated beam output from the second lens to form a processing beam acting on the workpiece to be processed.

2. The laser processing head according to claim 1, characterized in that, The second lens has a first curved surface and a second curved surface, the first curved surface facing the first lens and the second curved surface facing the third lens, the radius of curvature of the first curved surface is -750mm≤R3≤-610mm, and the radius of curvature of the second curved surface is 60mm≤R4≤90mm.

3. The laser processing head according to claim 1, characterized in that, The distance between the center of the second lens and the center of the first lens is 30mm≤l≤45mm.

4. The laser processing head according to claim 1, characterized in that, The third lens is either a biconvex lens or a positive meniscus lens.

5. The laser processing head according to claim 1, characterized in that, The waist diameter of the processing beam is less than 0.21 mm.

6. The laser processing head according to claim 1, characterized in that, The center thickness of the first lens is 3mm≤d1≤20mm.

7. The laser processing head according to claim 1, characterized in that, The center thickness of the second lens is 3mm≤d2≤20mm.

8. The laser processing head according to claim 1, characterized in that, It also includes a protective mirror disposed at the output end of the third lens.

9. A laser processing apparatus, characterized in that, Includes the laser processing head as described in any one of claims 1-8.

10. A laser processing system, characterized in that, Includes the laser processing apparatus as described in claim 9.

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