Optical path system, cutting head and apparatus for generating a high-power laser beam

Abstract

This application belongs to the field of laser beam shaping technology, specifically relating to an optical path system, a cutting head, and a device for generating high-power laser beams. The optical path system for generating high-power laser beams includes: a densely packed fiber optic module, a binary microlens array, and a 4F optical system arranged sequentially. The laser beam is transmitted through the densely packed fiber optic module to the binary microlens array, which shapes the laser beam into a flat-top beam. The flat-top beam is then passed through the 4F optical system to form a laser spot of a preset shape. The system of this application can conveniently obtain high-energy-density laser spots that meet user shape requirements.

Description

Technical Field

[0001] This application belongs to the field of laser beam shaping technology, specifically relating to an optical path system, cutting head, and device for generating high-power laser beams. Background Technology

[0002] Fiber lasers are lasers that use rare-earth-doped glass optical fibers as the gain medium. Fiber lasers have a wide range of applications, including laser fiber communication, industrial shipbuilding, automobile manufacturing, laser engraving and cutting, metal and non-metal drilling, cutting, welding, and so on.

[0003] The energy distribution of the laser beam output by a fiber laser is often Gaussian. In fiber laser processing, it is usually necessary to reshape the energy distribution of the laser beam to achieve a flat-top distribution in order to obtain a spot with uniform power density.

[0004] Existing beam shaping (Gaussian beam flattening) techniques are generally achieved using integrating mirrors or homogenizers. Integrating mirrors consist of many small plane mirrors, making their manufacturing process complex; homogenizers used in fiber lasers require very long lengths and suffer from high losses. When used in fiber lasers, both methods result in relatively large homogenized beam spots, making it difficult to generate high-brightness, high-power-density laser beam spots according to the user's requirements for beam shape.

[0005] How to make a laser output a high power density spot has become an urgent technical problem to be solved. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides an optical path system, cutting head and device for generating high-power laser beams.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, this application adopts the following technical solution:

[0010] In a first aspect, embodiments of this application provide an optical path system for generating a high-power laser beam. The system includes a densely packed fiber optic module, a binary microlens array, and a 4F optical system arranged sequentially. The laser beam is transmitted to the binary microlens array via the densely packed fiber optic module. The binary microlens array shapes the laser beam into a flat-top beam. The flat-top beam is then passed through the 4F optical system to form a laser spot of a preset shape.

[0011] Optionally, the structure of the binary microlens array is the same as that of the fiber optic densely packed module, and it is coated with an anti-reflection mode with a coating coefficient that is the same as the laser output wavelength.

[0012] Optionally, the 4F optical system includes a first aspherical mirror, a second aspherical mirror, and a shaping template disposed between the first and second aspherical mirrors. The first aspherical mirror includes a first incident surface and a second exit surface, wherein the first incident surface and the second exit surface have the same curvature direction. The second aspherical mirror includes a third incident surface and a fourth exit surface, wherein the fourth exit surface does not change the beam transmission direction.

[0013] Optionally, the surface shape distribution of the first incident surface is as follows:

[0014]

[0015] Where d1 is the distance between the center of the first incident surface and the light-emitting end of the binary microlens array, r is the perpendicular distance between the irradiation point of the light on the first incident surface and the central axis, and Z S (r) represents the sag of the surface at the corresponding irradiation point.

[0016] Optionally, the surface profile of the second exiting surface is as follows:

[0017]

[0018] Where z(r) is the surface sag at the radial position r of the second exit surface, n is the refractive index of the lens material, d is the distance between the center of the second exit surface and the center of the third incident surface, and f(x) is the relationship between the exit position r of the second exit surface and the incident position R of the third incident surface.

[0019] Optionally, the surface shape distribution of the third exit surface is as follows:

[0020]

[0021] Where Z(R) is the surface sag at the radial position R of the third incident surface.

[0022] Optionally, the fiber optic close-packed module includes:

[0023] The fiber bundle has the same fiber parameters as the output fiber of the laser generator that emits the laser beam. The fiber bundle is quadrilateral or hexagonal. The end face of the fiber bundle is ground, polished, and coated to form an anti-reflection film. The anti-reflection film coefficient is consistent with the output wavelength of the laser.

[0024] A fluorinated quartz tube is fitted onto the array optical fiber, and the refractive index of the fluorinated quartz tube is 1.37.

[0025] Secondly, embodiments of this application provide a laser cutting head, the laser cutting head including a laser output system and an optical path system for generating a high-power laser beam as described in any of the first aspects above, the optical path system for generating a high-power laser beam outputting a laser beam through the laser output system.

[0026] Thirdly, embodiments of this application provide a laser device, which includes a laser emitter and a laser cutting head as described in the second aspect above, wherein the laser emitted by the laser emitter enters the laser cutting head to generate a laser spot of a preset shape.

[0027] Optionally, the laser emitter is a fiber laser, and the output power range of the fiber laser is 1050nm to 1100nm.

[0028] (III) Beneficial Effects

[0029] The beneficial effects of this application are as follows: This application proposes an optical path system, a cutting head, and a device for generating high-power laser beams. The optical path system for generating high-power laser beams includes: a densely packed fiber optic module, a binary microlens array, and a 4F optical system arranged sequentially; the laser beam is transmitted through the densely packed fiber optic module to the binary microlens array, where the binary microlens array shapes the laser beam into a flat-top beam, and the flat-top beam is then shaped into a laser spot of a preset shape by the 4F optical system. The optical path system of this application, after densely packing multiple output fibers, obtains a uniform energy spot through the binary microlens, and then the 4F system shapes the spot, conveniently obtaining a high-energy-density laser spot that meets the user's shape requirements.

[0030] Furthermore, when processing metal sheets, the adjustment of binary microlenses can achieve many different shapes of light spots, thereby optimizing the surface roughness and taper of the sheet material during thick plate processing.

[0031] Laser spot shaping can improve the piercing process, creating a better molten pool and increasing piercing efficiency. Attached Figure Description

[0032] This application is described with reference to the following figures:

[0033] Figure 1 A schematic diagram of an optical path system for generating a high-power laser beam is provided in an embodiment of this application.

[0034] Figure 2 This is a schematic diagram of an optical fiber bundle structure in one embodiment of this application;

[0035] Figure 3 This is a schematic diagram of the 4F optical system structure in another embodiment of this application;

[0036] Figure 4 This is a comparison image of the 4F optical system before and after light spot processing in another embodiment of this application;

[0037] Figure 5 This is a structural diagram of the laser cutting head in another embodiment of this application. Detailed Implementation

[0038] To better explain and facilitate understanding of the present invention, it is described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described below are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other; for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0039] Example 1

[0040] Figure 1 A schematic diagram of an optical path system for generating a high-power laser beam is provided as an embodiment of this application, such as... Figure 1 As shown, the system includes:

[0041] The optical fiber densely packed module, the binary microlens array, and the 4F optical system are arranged in sequence. The laser beam is transmitted to the binary microlens array through the optical fiber densely packed module. The binary microlens array shapes the laser beam into a flat-top beam. The flat-top beam is then formed into a laser spot of a preset shape by the 4F optical system.

[0042] The optical path system of this application obtains a uniform energy spot by densely packing multiple output optical fibers and then using a binary microlens. The spot is then shaped by a 4F system, which can easily obtain a high energy density laser spot that meets the user's shape requirements.

[0043] To better understand the present invention, the various parts of this embodiment will be described in detail below.

[0044] 1. Fiber optic densely packed module

[0045] The fiber optic densely packed module contains multiple optical fibers precisely arranged inside, integrating multiple laser beams at a certain interval through the fiber optic array module and lens.

[0046] The fiber optic close-packed module includes:

[0047] The fiber bundle has the same fiber parameters as the output fiber of the laser generator that emits the laser beam. The end face of the fiber bundle is ground, polished, and coated to form an anti-reflection film. The anti-reflection film coefficient is consistent with the output wavelength of the laser.

[0048] A fluorinated quartz tube is fitted onto the array optical fiber, and the refractive index of the fluorinated quartz tube is 1.37.

[0049] The fabrication methods for fiber optic close-packed modules include:

[0050] Hydrofluoric acid is used to remove the cladding of the optical fiber;

[0051] Optical fibers are bundled together by using a fluorinated quartz tube to form an optical fiber bundle.

[0052] The fiber bundle end face is ground, polished, and coated, with the anti-reflection coating coefficient being consistent with the laser output wavelength.

[0053] Figure 2 This is a schematic diagram of the fiber bundle structure in one embodiment of this application. Figure 2 In the diagram, (a), (b), (c), (d), and (e) represent a triangle, a quadrilateral, and a hexagon with 2, 3, and 4 optical fibers per side, respectively. Figure 2 As shown, the shape of the close-packed fiber array can be triangular, quadrilateral, or hexagonal, and the number of fibers is greater than or equal to 3. Preferably, the shape of the close-packed fiber array is quadrilateral or hexagonal.

[0054] Fiber optic close-packed modules can also employ other methods for fiber optic close packing. For example, all the fibers can be fixed into a specific shape using a pre-prepared arrangement mold. Figure 2 The shape shown can also be rectangular or other shapes; this embodiment does not impose specific limitations on the shape of the fiber optic densely packed module. The main function of the arrangement mold is to arrange the optical fibers in a regular manner before grinding, polishing, and coating processes are performed.

[0055] 2. Binary microlens array

[0056] In this embodiment, the microlens array is a refractive microlens array, in which each microlens corresponds to an optical fiber in the close-packed fiber array, and the microlens array is positioned at the first focal length of the 4f system. The binary microlens array divides a complete laser wavefront into many tiny parts in space, each part being focused onto the focal plane by a corresponding microlens, and the light spots overlap, thereby achieving precise shaping to homogenize the light.

[0057] Binary microlens arrays are primarily used to disrupt the mode field distribution of Gaussian or Gaussian-like light, transforming the Gaussian beam into a flat-top beam with uniform energy. The structure of the binary microlens array is consistent with that of the close-packed fiber optic module, employing anti-reflection coating treatment, with the coating coefficient matching the laser output wavelength.

[0058] Furthermore, when processing metal sheets, the adjustment of binary microlenses can achieve many different shapes of light spots, thereby optimizing the surface roughness and taper of the sheet material during thick plate processing.

[0059] Example 2

[0060] This embodiment provides an optical path system for generating high-power laser beams. The fiber optic dense-packed module and binary microlens array are the same as in Embodiment 1. Therefore, the following only describes the 4F optical system in this embodiment.

[0061] The 4F optical system is used to reshape a uniform flat-top light spot to achieve a light spot that can be adapted to different processing scenarios.

[0062] Figure 3 This is a schematic diagram of the 4F optical system structure in another embodiment of this application, as shown below. Figure 3 As shown, the 4F optical system includes a first aspherical mirror 1, a second aspherical mirror 2, and a shaping template 3 disposed between the first aspherical mirror 1 and the second aspherical mirror 2. The first aspherical mirror 1 includes a first incident surface R1 and a second exit surface R2. The first incident surface R1 and the second exit surface R2 have the same curvature direction, both curving along the optical path. The second aspherical mirror 2 includes a third incident surface R3 and a fourth exit surface R4. The fourth exit surface R4 does not change the beam transmission direction. d1 is the distance between the center of the first incident surface R1 and the light-emitting end of the binary microlens array 4, and d is the distance between the center of the second exit surface R2 and the center of the third incident surface R3.

[0063] Figure 3 The surface shape distribution of the first incident surface R1 is as follows:

[0064]

[0065] Where d1 is the distance between the center of the first incident surface R1 and the light-emitting end of the binary microlens array, r is the perpendicular distance between the ray's illumination point on the first incident surface R1 and the central axis, and Z... S (r) represents the sag of the surface at the corresponding irradiation point.

[0066] Figure 3 The surface shape distribution of the second exit surface R2 is as follows:

[0067]

[0068] Where z(r) is the surface sag at the radial position r of the second exit surface R2, n is the refractive index of the lens material, d is the distance between the center of the second exit surface R2 and the center of the third incident surface R3, and f(x) is the relationship between the exit position r of the second exit surface and the incident position R of the third incident surface.

[0069] Figure 3 The surface shape distribution of the third incident surface R3 is as follows:

[0070]

[0071] Where Z(R) is the surface sag at the radial position R of the incident surface R3.

[0072] Preferably, different shapes of light spots can be obtained by adjusting the shape of the shaping template.

[0073] Figure 4 This is a comparison image of the 4F optical system before and after light spot processing in another embodiment of this application. Figure 4 In the diagram, (a), (b), (c), and (d) represent four different shapes of light spots obtained after processing the flat-top light spot using a shaping template. Figure 4 As shown, the flat-top light spot will obtain the following after being processed by the 4F optical system: Figure 4 The different spot shapes shown are used to improve the efficiency of perforation, cutting, welding and the quality of finished products.

[0074] Apart from Figure 4 The four light spot shapes shown can be further adjusted to make the flat-top light spot into a ring shape or a ring with a flat top at the center, thereby improving the effect and efficiency of various applications.

[0075] With the 4F optical system of this embodiment, not only are the integrated laser axes parallel, the light spots uniform, and the energy similar, but the shape of the light spots formed by the shaping template can also be controlled more accurately. With computer control, multiple lasers can work simultaneously, and the processes of plate making, welding, engraving, and detection can be realized efficiently and perfectly.

[0076] Example 3

[0077] Figure 5 This is a structural diagram of the laser cutting head in another embodiment of this application, as shown below. Figure 5 As shown, a second aspect of this application provides a laser cutting head, including a laser output system and an optical path system for generating a high-power laser beam as described in the above embodiment. The optical path system for generating the high-power laser beam outputs a laser beam through the laser output system.

[0078] The specific structure of the optical path system includes a laser, a densely packed fiber module, a binary microlens array, a 4F optical system, and a laser output device. Since this laser cutting head adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0079] The optical path system is housed within a housing. This housing forms a recessed space within which the optical path system is housed. The housing protects the internal optical path system from external dust and debris. A sensor can also be mounted on the housing to detect the distance between the laser cutting head and the workpiece. This sensor can be connected to an external height adjustment system, which adjusts the distance between the laser cutting head and the workpiece based on the sensor's data. This ensures that the laser beam emitted from the laser cutting head's optical path system is focused to the same height as the workpiece, guaranteeing stable cut dimensions during the laser cutting process.

[0080] Example 4

[0081] A third aspect of this application provides a laser device, which includes a laser generator and a laser cutting head as described in the above embodiments, wherein the laser emitted by the laser generator enters the laser cutting head to generate a laser spot of a preset shape.

[0082] Specifically, the laser generator is a solid-state laser, preferably a fiber laser. The laser output exhibits a Gaussian distribution, and all outputs are from a single bare fiber with a fiber core diameter of 10μm to 100μm. The laser output power is typically between 0.1 and 25 kW, preferably between 10W and 20 kW, and the laser output wavelength is preferably between 1050 nm and 1100 nm.

[0083] Laser generators can operate in continuous, quasi-continuous, or pulsed modes.

[0084] As a laser source, it is coupled to an optical fiber in a close-packed fiber optic module to generate an incident laser beam.

[0085] Specifically, the laser output device can be either fiber optic output or spatial optical path output.

[0086] Since this laser cutting equipment adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0087] It should be noted that any reference numerals placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The words "a" or "an" preceding a component do not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. The use of the terms first, second, third, etc., is for convenience only and does not indicate any order. These terms can be understood as part of the component names.

[0088] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0089] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims should be interpreted to include both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0090] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention should also include these modifications and variations.

Claims

1. An optical path system for generating a high-power laser beam, characterized in that, The system includes a densely packed fiber optic module, a binary microlens array, and a 4F optical system arranged in sequence. The laser beam is transmitted to the binary microlens array via the densely packed fiber optic module. The binary microlens array shapes the laser beam into a flat-top beam. The flat-top beam is then passed through the 4F optical system to form a laser spot of a preset shape. The fiber optic densely packed module contains multiple fiber bundles that are precisely arranged inside, integrating multiple laser beams at a certain interval through the fiber array module and lens; Multiple fiber bundles are fiber bundles with the fiber cladding removed and encased in fluorine-quartz tubes. The anti-reflection coating coefficient at the end face of the fiber bundle is consistent with the output wavelength of the laser. The microlens array is a refractive microlens array. Each microlens in the microlens array is set to correspond to an optical fiber in the close-packed optical fiber array, and the microlens array is placed at the first focal length of the 4F optical system. The binary microlens array divides a complete laser wavefront into many tiny parts in space. Each part is focused on the focal plane by the corresponding small lens, and the light spots overlap, thereby achieving precise shaping to homogenize the light. The 4F optical system includes a first aspherical mirror, a second aspherical mirror, and a shaping template disposed between the first and second aspherical mirrors. The first aspherical mirror includes a first incident surface and a second exit surface, with the first incident surface and the second exit surface having the same curvature direction. The second aspherical mirror includes a third incident surface and a fourth exit surface, with the fourth exit surface not changing the beam transmission direction.

2. The optical path system for generating a high-power laser beam according to claim 1, characterized in that, The structure of the binary microlens array is the same as that of the fiber optic densely packed module, and it is coated with an antireflection film with a coating coefficient that is the same as the laser output wavelength.

3. The optical path system for generating a high-power laser beam according to claim 1, characterized in that, The surface shape distribution of the first incident surface is as follows: ； Where d1 is the distance between the center of the first incident surface and the light-emitting end of the binary microlens array, r is the perpendicular distance between the irradiation point of the first incident surface and the central axis, and Z S (r) represents the sag of the surface at the corresponding irradiation point.

4. The optical path system for generating a high-power laser beam according to claim 3, characterized in that, The surface profile of the second exit surface is as follows: ； Where z(r) is the surface sag at the radial position r of the second exit surface, n is the refractive index of the lens material, d is the distance between the center of the second exit surface and the center of the third incident surface, and f(x) is the relationship between the exit position r of the second exit surface and the incident position R of the third incident surface.

5. The optical path system for generating a high-power laser beam according to claim 3, characterized in that, The surface shape distribution of the third incident surface is as follows: ； Where Z(R) is the surface sag at the radial position R of the third incident surface.

6. The optical path system for generating a high-power laser beam according to claim 1, characterized in that, The fiber optic dense-pack module includes: The fiber bundle has the same fiber parameters as the output fiber of the laser generator that emits the laser beam. The fiber bundle is quadrilateral or hexagonal. The end face of the fiber bundle is ground, polished, and coated to form an anti-reflection film. The anti-reflection film coefficient is consistent with the output wavelength of the laser. A fluorinated quartz tube is fitted onto the array optical fiber, the refractive index of which is 1.

37.

7. A laser cutting head, characterized in that, The laser cutting head includes a laser output system and an optical path system for generating a high-power laser beam as described in any one of claims 1 to 6, wherein the optical path system for generating the high-power laser beam outputs a laser beam through the laser output system.

8. A laser device, characterized in that, The laser device includes a laser emitter and a laser cutting head as described in claim 7, wherein the laser emitted by the laser emitter enters the laser cutting head to generate a laser spot of a preset shape.

9. The laser device according to claim 8, characterized in that, The laser emitter is a fiber laser, and the output power range of the fiber laser is 1050nm~1100nm.

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