Wire cutting head, laser cutting system and wire cutting head design method

Abstract

The present invention provides a filamentation cutting head, a laser cutting system and a design method for a filamentation cutting head, which relate to the field of laser control technology. The filamentation cutting head includes a shaping element, a collimating element and a focusing element arranged in sequence along the propagation direction of light. The laser beam emitted by the laser is converted into a flat-top beam by a shaping element having a first surface shape, and its divergence angle is controlled by the collimation of the collimating element. Finally, it is converged into a target filamentation beam with high energy utilization and high uniformity by a focusing element having a second surface shape. This filamentation beam can realize laser cutting of hard and brittle materials and improve the processing effect. At the same time, the filamentation cutting head adopts a full-refractive element, which not only has the advantages of a simple design method, low lens processing difficulty, and the ability to cope with a variety of materials, but can also convert all Gaussian beams into flat-top beams, so that all input energy is utilized in the filamentation beam.

Description

Technical Field

[0001] The present invention relates to the field of laser control technology, and in particular to a filament cutting head, a laser cutting system and a filament cutting head design method. Background Art

[0002] With the continuous development of the electronics industry, the majority of materials used in electronic product panels are hard and brittle materials, such as sapphire, glass, and ceramics. These materials vary in thickness and thickness, requiring appropriate and controllable processing methods. This presents challenges for the hard and brittle material processing industry.

[0003] In the existing technology, when using laser to cut and process hard and brittle materials, the spot size and focal depth range of the focused light spot are limited by the diffraction limit and optical aberrations. There is a phenomenon that the light beam cannot penetrate the hard and brittle materials, making it difficult to achieve the ideal processing effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a filament cutting head, a laser cutting system and a filament cutting head design method to achieve high energy utilization and high uniformity of the filament beam and improve the processing effect.

[0005] In a first aspect, an embodiment of the present invention provides a filament cutting head, comprising a shaping element, a collimating element, and a focusing element sequentially arranged along a propagation direction of light;

[0006] The shaping element is an aspherical lens; the shaping element has a first surface shape, and is used to convert an input non-top-hat beam into an output top-hat beam; the first surface shape is determined based on first beam energy distribution information on an input surface of the shaping element, as well as desired beam propagation distance and desired top-hat beam energy distribution information;

[0007] The collimating element is used to collimate the input flat-top beam; the distance between the collimating element and the shaping element is consistent with the desired beam propagation distance;

[0008] The focusing element is an aspherical lens; the focusing element has a second surface shape, which is used to converge the collimated flat-top beam into a target filamentary beam; the second surface shape is determined based on the flat-top beam diameter information and the second beam energy distribution information on the input surface of the focusing element, as well as the expected focal depth and the peak energy distribution information along the optical axis within the focal depth range.

[0009] Furthermore, the filament cutting head further comprises a controller, a beam analyzer and a transmission device; the beam analyzer and the transmission device are respectively connected to the controller;

[0010] The beam profiler is used to detect the beam quality information within the focal depth range of the focusing element and send it to the controller; wherein the beam quality information includes the spot energy distribution information;

[0011] The controller is used to control the transmission device to adjust the distance between the shaping element and the collimating element based on the received light spot energy distribution information.

[0012] Furthermore, the controller is further configured to compare the received spot energy distribution information with the preset standard energy distribution information for consistency, and when the comparison result is inconsistent, send an adjustment instruction to the transmission device;

[0013] The transmission device is used to drive the shaping element to move when receiving an adjustment instruction, so as to adjust the distance between the shaping element and the collimating element.

[0014] Furthermore, the transmission device includes a fixed seat, a motor, a crank-connecting rod mechanism, a mirror seat and a guide rail;

[0015] The motor and the guide rail are fixed on the fixed seat, the mirror base is slidably connected to the guide rail, and the mirror base is used to install the shaping element and / or the collimating element; the motor is connected to the mirror base through a crank connecting rod mechanism, driving the mirror base to slide on the guide rail.

[0016] Furthermore, the beam quality information also includes spot size information and focal depth information; the controller is further configured to detect the quality of the filament cutting head based on the received spot size information and focal depth information.

[0017] In a second aspect, an embodiment of the present invention further provides a laser cutting system, comprising a laser and the filament cutting head of the first aspect; the laser emits a laser beam toward the filament cutting head.

[0018] In a third aspect, an embodiment of the present invention further provides a method for designing a filament cutting head, which is applied to the filament cutting head of the first aspect; the method comprises:

[0019] Obtaining shaping element design data and focusing element design data corresponding to the filament cutting head; wherein the shaping element design data includes first beam energy distribution information on the input surface of the shaping element, as well as desired beam propagation distance and desired flat-top beam energy distribution information; and the focusing element design data includes flat-top beam diameter information on the input surface of the focusing element, second beam energy distribution information, as well as desired focal depth and peak energy distribution information along the optical axis within the focal depth range;

[0020] determining a first surface shape of the shaping element according to the shaping element design data;

[0021] The second surface shape of the focusing element is determined according to the focusing element design data.

[0022] Furthermore, determining the first surface shape of the shaping element according to the shaping element design data includes:

[0023] determining energy distribution information of a third beam on an output surface of the shaping element according to a desired beam propagation distance and desired flat-top beam energy distribution information;

[0024] The first surface shape of the shaping element is determined according to the third beam energy distribution information, the first beam energy distribution information and a plurality of preset first surface shape parameters.

[0025] Furthermore, determining the second surface shape of the focusing element according to the focusing element design data includes:

[0026] Determining angle information between a plurality of outgoing light rays in an output light beam of a focusing element and the optical axis according to the desired focal depth and peak energy distribution information;

[0027] The second surface shape of the focusing element is determined according to the angle information, the flat-top beam diameter information, the second beam energy distribution information and a plurality of preset second surface shape parameters.

[0028] Furthermore, the first beam energy distribution information includes the energy intensity of the Gaussian beam at each position expressed in matrix form; the surface shape formulas corresponding to the first surface shape and the second surface shape are:

[0029]

[0030] Where z is the height of the aspheric surface under fixed Y, Y is the distance from the center of the lens plane to any horizontal direction, R, k, A4, A6, A8, A 10 、A 12 、A 14 、A 16 is the surface parameter.

[0031] In the filament cutting head, laser cutting system and filament cutting head design method provided by the embodiments of the present invention, the filament cutting head includes a shaping element, a collimating element and a focusing element arranged in sequence along the propagation direction of light; the shaping element is an aspherical lens; the shaping element has a first surface shape, which is used to convert the input non-flat top beam into a flat top beam output; the first surface shape is determined based on the first beam energy distribution information on the input surface of the shaping element, as well as the expected beam propagation distance and the expected flat top beam energy distribution information; the collimating element is used to collimate the input flat top beam; the distance between the collimating element and the shaping element is consistent with the expected beam propagation distance; the focusing element is an aspherical lens; the focusing element has a second surface shape, which is used to converge the collimated flat top beam into a target filament beam; the second surface shape is determined based on the flat top beam diameter information and the second beam energy distribution information on the input surface of the focusing element, as well as the expected focal depth and the peak energy distribution information along the optical axis within the focal depth range. In this way, the laser beam emitted by the laser is converted into a flat-top beam through a shaping element, and then its divergence angle is controlled by the collimation element. Finally, it is converged by the focusing element into a target filamentation beam with high energy utilization and high uniformity. This filamentation beam can realize laser cutting of hard and brittle materials and improve the processing effect. At the same time, the filamentation cutting head adopts a full-refractive element, which not only has the advantages of simple design method, low lens processing difficulty, and the ability to cope with a variety of materials, but also can convert all Gaussian beams into flat-top beams, and utilize all the input energy for the filamentation beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic structural diagram of a filament cutting head provided in an embodiment of the present invention;

[0034] Figure 2 A schematic structural diagram of a laser cutting system provided by an embodiment of the present invention;

[0035] Figure 3 A schematic flow chart of a method for designing a filament cutting head provided in an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of a flattened effect of converting a Gaussian beam into a flattened beam provided by an embodiment of the present invention;

[0037] Figure 5A schematic diagram of the collimation effect of converting a flat-top beam into a collimated beam provided by an embodiment of the present invention;

[0038] Figure 6 A schematic diagram of axial peak energy distribution within a focal depth range provided by an embodiment of the present invention;

[0039] Figure 7 A schematic diagram of cross-sectional energy distribution within a focal depth range provided by an embodiment of the present invention.

[0040] Icon: 101-shaping element; 102-collimating element; 103-focusing element; 201-laser; 202-beam expander; 203-reflector. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] Existing laser cutting heads for cutting hard and brittle products primarily utilize diffraction optics theory and polarization / diffraction optical elements to direct a Gaussian beam through a system similar to an axicon, before a focusing objective forms an axial beam with the desired focal depth and energy distribution. The first lens is a polarizing element, used to adjust the polarization state of the beam; the second lens is a diffraction element, which receives a fixed polarization state to achieve the desired spot state; and the third lens is a focusing objective, which focuses the beam into an axial beam with the desired focal depth and energy distribution.

[0043] The above scheme has the following defects: due to the complexity of diffraction optical theory and the difficulty of the diffraction optical element manufacturing process, its debugging difficulty and device price are usually much higher than those of refractive elements. At the same time, due to the variability of materials, different materials have different requirements for polarization, and the cutting head manufactured based on polarization optical design often conflicts with this. In addition, because the Gaussian beam is converted into a Bessel beam, the energy below the half-width of the Gaussian beam usually cannot be controlled as an actual effective cutting focal depth area, which reduces the energy utilization of the cutting head.

[0044] Based on this, embodiments of the present invention provide a filamentation cutting head, laser cutting system, and filamentation cutting head design method. The filamentation cutting head, composed of a fully refractive element, not only offers the advantages of a simple design, low lens processing difficulty, and compatibility with a wide range of materials, but also converts a Gaussian beam into a flat-top beam, fully utilizing the input energy in the filamentation beam, resulting in a highly energy-efficient and uniform filamentation beam. This filamentation beam is suitable for laser cutting hard and brittle materials such as sapphire, improving the processing efficiency of these materials.

[0045] It should be noted that the above-mentioned hard and brittle material is not limited to sapphire, and may also be glass, ceramics or other materials.

[0046] To facilitate understanding of this embodiment, a filament cutting head disclosed in an embodiment of the present invention is first introduced in detail.

[0047] like Figure 1 As shown, an embodiment of the present invention provides a filament cutting head, comprising a shaping element 101, a collimating element 102 and a focusing element 103 arranged in sequence along the propagation direction of light.

[0048] The shaping element 101 is an aspherical lens having a first surface shape for converting an input non-top-hat beam into an output top-hat beam. The first surface shape is determined based on the first beam energy distribution information on the input surface of the shaping element 101, as well as the desired beam propagation distance and the desired top-hat beam energy distribution information. The input non-top-hat beam can be, but is not limited to, a Gaussian beam. The Gaussian beam can be emitted by an ultrafast laser, such as an infrared laser, to produce an ideal Gaussian beam. The first beam energy distribution information can be the energy distribution information of the Gaussian beam emitted by the laser, and can include the energy intensity of the Gaussian beam at each position, represented in matrix form. The first beam energy distribution information, the desired beam propagation distance, and the desired top-hat beam energy distribution information are all preset by the user.

[0049] The collimating element 102 is used to collimate the input flat-top beam; the distance between the collimating element 102 and the shaping element 101 is consistent with the desired beam propagation distance. Consistent here means that the distance between the collimating element 102 and the shaping element 101 is within a distance range centered on the desired beam propagation distance. The size of this distance range can be set according to actual needs and is not limited here. For example, if the desired beam propagation distance is 150mm, the distance between the collimating element 102 and the shaping element 101 can be between 145mm and 155mm. The collimating element 102 can use a plano-convex lens or an aspherical lens, wherein plano-convex lenses are less expensive.

[0050] Focusing element 103 is an aspheric lens; it has a second surface shape for converging the collimated flat-top beam into a target filamentary beam. This second surface shape is determined based on the flat-top beam diameter information and second beam energy distribution information on the input surface of focusing element 103, as well as the desired focal depth and peak energy distribution information along the optical axis within the focal depth range. The focal depth refers to the front-to-back distance that a lens can focus while maintaining acceptable clarity. The focal depth range refers to the distance range from the closest clear point to the farthest clear point. The flat-top beam diameter information, second beam energy distribution information, desired focal depth, and peak energy distribution information are all preset by the user. The flat-top beam diameter information and second beam energy distribution information correspond to the desired flat-top beam energy distribution information and can be determined by the desired flat-top beam energy distribution information and the beam conversion relationship corresponding to collimating element 102.

[0051] The distance between the focusing element 103 and the collimating element 102 can be set based on factors such as size, weight, installation, and graphic design. Optionally, the distance between the focusing element 103 and the collimating element 102 is between 0.5 mm and 3 mm. For example, the distance between the focusing element 103 and the collimating element 102 is 1 mm. This facilitates both installation of the focusing element 103 and the collimating element 102 and graphic design.

[0052] The center positions of the shaping element 101 , the collimating element 102 and the focusing element 103 are all coincident with the optical axis, thus ensuring the quality of the output filamentary light beam.

[0053] In one possible implementation, the Gaussian beam generated by the infrared laser passes through the shaping element 101 and is converted into a flat-top beam after traveling a certain distance (i.e., the desired beam propagation distance) based on the beam propagation theory; the divergence angle of the beam is then controlled by the collimating element 102, and finally the beam is converged by the focusing element 103 into a filamentary beam with high energy utilization and high uniformity.

[0054] The key points of the embodiments of the present invention lie in the performance characteristics and usage methods of the three elements. The shaping element 101 can convert a Gaussian beam into a flat-top beam to ensure high energy utilization and high uniformity of the axial energy distribution; the collimating element 102 can convert the light beam entering the focusing element 103 into a collimated beam; the focusing element 103 plays a converging role, ultimately forming a filamentary beam with high energy utilization and high uniformity.

[0055] For the above-mentioned filamentation cutting head, the laser beam emitted by the laser is converted into a flat-top beam by the shaping element 101, and then its divergence angle is controlled by the collimation element 102, and finally converged by the focusing element 103 into a target filamentation beam with high energy utilization and high uniformity. This filamentation beam can realize laser cutting of hard and brittle materials and improve the processing effect; at the same time, the shaping element 101, the collimation element 102 and the focusing element 103 are all refractive elements, that is, the filamentation cutting head adopts a full refractive element, which not only has the advantages of simple design method, low lens processing difficulty, and the ability to cope with a variety of materials, but also can convert all Gaussian beams into flat-top beams, and utilize all the input energy for the filamentation beam.

[0056] Optionally, the filamentation cutting head further includes a controller, a beam profiler, and a transmission device; the beam profiler and the transmission device are respectively connected to the controller; the beam profiler is used to detect beam quality information within the focal depth range of the focusing element 103 and transmit it to the controller; the beam quality information includes spot energy distribution information; the controller is used to control the transmission device to adjust the distance between the shaping element 101 and the collimating element 102 based on the received spot energy distribution information. This achieves automatic adjustment of the target filamentation beam and ensures the quality of the target filamentation beam.

[0057] The beam profiler can be positioned at the working distance of the filament cutting head, i.e., at the focal point. The beam profiler can detect the spot energy distribution and spot size at that location, as well as the depth of focus. The spot energy distribution information output by the beam profiler can be used to adjust the distance between the shaping element 101 and the collimating element 102, while the spot size and depth of focus information can be used to determine the quality of the filament cutting head.

[0058] Under the control of the controller, the transmission device can drive the shaping element 101 and / or the collimating element 102 to move, thereby adjusting the distance between the shaping element 101 and the collimating element 102. Preferably, the transmission device adjusts the distance between the shaping element 101 and the collimating element 102 by driving the shaping element 101 to move, thereby eliminating the need for subsequent adjustment of the focusing element 103. This simple and quick adjustment method.

[0059] In one possible implementation, taking the transmission device driving the shaping element 101 to move as an example, the above-mentioned controller is also used to compare the received spot energy distribution information with the preset standard energy distribution information for consistency. When the comparison result is inconsistent, an adjustment instruction is sent to the transmission device; the transmission device is used to drive the shaping element 101 to move when receiving the adjustment instruction, so as to adjust the distance between the shaping element 101 and the collimating element 102.

[0060] In specific implementation, the consistency comparison process can be as follows: first, the deviation between the received spot energy distribution information and the standard energy distribution information is calculated to obtain an energy distribution deviation value; then, a determination is made as to whether the energy distribution deviation value is less than a preset energy deviation threshold. If so, the comparison result is determined to be consistent; conversely, if not, the comparison result is determined to be inconsistent. The energy deviation threshold can be set based on actual needs and is not limited here.

[0061] When calculating the deviation between the received light spot energy distribution information and the standard energy distribution information, a focus area and a peripheral area may be divided.

[0062] As an example, the received spot energy distribution information is an M×N energy distribution matrix E, where E ij Represents the energy intensity at position (i, j). The standard energy distribution information is the standard energy distribution matrix S, where S ij Indicates the energy intensity at the corresponding position.

[0063] Assume that the radius of the focus area is r. In order to reduce the amount of calculation, the focus area can be defined as a rectangular area around the center point:

[0064] (x0-r, x0+r)×(y0-r, y0+r)

[0065] Where (x0, y0) is the position of the center of the focus.

[0066] Of course, it can also be defined as other shapes, such as a circle, according to actual conditions.

[0067] The deviation value of the focal area between the received spot energy distribution information and the standard energy distribution information can be calculated. For example, the mean squared error (MSE) in the focal area can be calculated:

[0068]

[0069] Among them, N focus is the total number of pixels in the focus area.

[0070] Then calculate the deviation value of the peripheral area between the received spot energy distribution information and the standard energy distribution information. The peripheral area refers to all areas except the focus area. For the peripheral area, the mean absolute error (MAE) can be calculated:

[0071]

[0072] Among them, N outside is the total number of pixels within the peripheral area.

[0073] The deviation values ​​of the focal area and the peripheral area can be combined to obtain the energy distribution deviation value:

[0074] Total Deviation=w focus MSE focus +w outside MAE outside

[0075] Among them, w focus and w outside is the weight factor of the focal area and the peripheral area, which can be adjusted according to actual needs. The weight factor of the focal area can be greater than the weight factor of the peripheral area.

[0076] In some embodiments, the weight of the focus area may be 0.9, and the weight of the peripheral area may be 0.1, which means that the deviation value of the focus area is more important.

[0077] Optionally, the transmission device may include a fixed seat, a motor, a crank-connecting rod mechanism, a mirror seat and a guide rail; the motor and the guide rail are fixed on the fixed seat, the mirror seat is slidably connected to the guide rail, and the mirror seat is used to install the shaping element 101 and / or the collimating element 102; the motor is connected to the mirror seat through the crank-connecting rod mechanism, driving the mirror seat to slide on the guide rail, that is, driving the shaping element 101 or the collimating element 102 to slide on the guide rail, thereby realizing the distance adjustment between the shaping element 101 and the collimating element 102.

[0078] Optionally, the beam quality information further includes spot size information and focal depth information; and the controller is further configured to detect the quality of the filament cutting head based on the received spot size information and focal depth information, thereby achieving automatic detection of the quality of the filament cutting head.

[0079] In specific implementation, the quality inspection process of the filament cutting head can be as follows: first calculate the deviation between the spot size information and the standard spot size, as well as the deviation between the depth of focus information and the standard depth of focus, to obtain the size deviation value and the depth of focus deviation value, and then compare the size deviation value and the depth of focus deviation value with the preset size threshold and depth of focus threshold respectively. If the size deviation value is less than the size threshold, and the depth of focus deviation value is less than the depth of focus threshold, it is determined that the quality of the filament cutting head is qualified; otherwise, if the size deviation value is not less than the size threshold, or the depth of focus deviation value is not less than the depth of focus threshold, it is determined that the quality of the filament cutting head is unqualified.

[0080] Further optionally, the controller is also used to issue an alarm when the quality of the wire cutting head is unqualified, such as by one or more of an audible and visual alarm, a text message, a phone call, and an email. In this way, the user can be notified of the unqualified quality in a timely manner.

[0081] The embodiment of the present invention also provides a laser cutting system, such as Figure 2 As shown, the system includes a laser 201 and the aforementioned filament cutting head; the laser 201 emits a laser beam toward the filament cutting head.

[0082] The laser 201 may be, but is not limited to, an infrared laser, and the laser beam may be, but is not limited to, a Gaussian beam.

[0083] Furthermore, in a possible implementation, as Figure 2 As shown, a beam expander 202 and a reflector 203 are further provided between the laser 201 and the shaping element 101; the beam expander 202 is used to expand the laser beam emitted by the laser, that is, to increase the beam diameter; the reflector 203 is used to change the propagation direction of the expanded laser beam to achieve filamentous beam output in a specified direction.

[0084] The embodiment of the present invention further provides a method for designing a filament cutting head, which is applied to the above-mentioned filament cutting head and can be executed by a computer device with data processing capabilities. Figure 3 The flowchart of a method for designing a filament cutting head is shown, and the method mainly includes the following steps S310 to S330:

[0085] Step S310: Acquire shaping element design data and focusing element design data corresponding to the filament cutting head.

[0086] Among them, the shaping element design data includes the first beam energy distribution information on the input surface of the shaping element, as well as the expected beam propagation distance and the expected flat-top beam energy distribution information; the focusing element design data includes the flat-top beam diameter information and the second beam energy distribution information on the input surface of the focusing element, as well as the expected focal depth and the peak energy distribution information along the optical axis within the focal depth range.

[0087] The first beam energy distribution information may include the energy intensity of the Gaussian beam at each position expressed in a matrix form.

[0088] Step S320: determining a first surface shape of the shaping element according to the shaping element design data.

[0089] In some possible embodiments, the third beam energy distribution information on the output surface of the shaping element can be determined based on the expected beam propagation distance and the expected flat-top beam energy distribution information; and then the first surface shape of the shaping element can be determined based on the third beam energy distribution information, the first beam energy distribution information and the preset multiple first surface shape parameters.

[0090] The first surface parameters may include, for example, the radius of curvature and the quadratic surface coefficient. In specific implementations, optical design software (such as Matlab and Zemax) can be used to design the shaping element and verify its effects. The shape of the shaping element can be represented by a polynomial function with the first surface parameters, such as a Zernike polynomial. Ray tracing software (such as Zemax) can be used to simulate the distribution of a light beam after passing through an aspheric lens, adjusting the first surface parameters until the desired flat-top beam distribution is achieved. It should be noted that ray tracing software is not limited to Zemax; in other embodiments, software such as LightTools or TracePro can also be used.

[0091] Step S330: determining a second surface shape of the focusing element according to the focusing element design data.

[0092] In some possible embodiments, the angle information between multiple outgoing light rays in the output light beam of the focusing element and the optical axis can be first determined based on the desired focal depth and peak energy distribution information; and then the second surface shape of the focusing element can be determined based on the angle information, the flat-top beam diameter information, the second beam energy distribution information and the preset multiple second surface shape parameters.

[0093] In specific implementation, after obtaining the angle information, the focal depth range can be divided into multiple segments, and each segment can be set with an angle between the outgoing light and the optical axis. Then, similar to the surface design method of the shaping element, ray tracing can be performed through optical design software, and the second surface parameters can be adjusted until the desired focal depth is reached, thereby finding the optimal surface shape.

[0094] It should be noted that there is no order of execution between the above-mentioned step S320 and step S330. The two can be executed in parallel, or step S320 can be executed first and then step S330; or step S330 can be executed first and then step S320.

[0095] The embodiment of the present invention designs a filament cutting head with high energy utilization and high uniformity. The laser beam passes through a shaping element, a collimating element and a focusing element in sequence, and finally forms a filament beam with high energy utilization and high uniformity. It not only has the advantages of simple design concept and easy lens processing, but more importantly, its high energy utilization and high uniformity can ensure that hard and brittle materials can be cut evenly. Therefore, this solution can achieve good cutting of hard and brittle materials.

[0096] In one possible implementation, when determining the first surface shape of the shaping element, first, the energy distribution of the Gaussian beam is calculated in matrix form to obtain the energy intensity corresponding to each position (Gaussian beam matrix, i.e., the first beam energy distribution information). By giving the desired beam propagation distance (i.e., the desired beam propagation distance) and the flat-top beam energy distribution on the collimating element, the flat-top beam energy distribution still represents the energy intensity corresponding to each position in matrix form (flat-top beam matrix, i.e., the desired flat-top beam energy distribution information). Subsequently, the surface shape of the shaping element (i.e., the first surface shape) is reversely calculated based on the Gaussian beam matrix, the beam propagation distance, and the flat-top beam matrix. Once the lens surface shape of the shaping element is confirmed, the desired flat-top beam can be obtained at the collimating element, and the energy of the beam is approximately consistent throughout the entire cross section, such as Figure 4 As shown ( Figure 4 obtained through simulation), which facilitates obtaining a filamentary beam with high energy utilization and high uniformity. Figure 4 The color of the Y-direction color map in the figure represents the energy intensity. The color of the Y-direction color map at the observation surface is relatively uniform, indicating that the energy is relatively consistent.

[0097] like Figure 5 As shown ( Figure 5 (obtained through simulation), the collimating element 102 is a plano-convex lens, and the convex surface of the plano-convex lens is used to collimate the divergent flat-top beam, so that the light beam after passing through the collimating element 102 becomes a parallel and collimated flat-top beam. That is, the divergent light beam passing through the shaping element 101 is compressed to a parallel state after passing through the collimating element 102, and the light beam has a flat-top distribution along the Y direction of the light beam between the collimating element 102 and the focusing element 103 (the color of the Y-direction color map at the observation surface is relatively uniform, indicating relatively consistent energy). In this way, by improving the divergence angle of the light beam, it is possible to ensure that the light beam incident on the focusing element 103 is a parallel flat-top beam.

[0098] When determining the second surface shape of the focusing element, first, according to the design requirements, the desired focal depth along the Z axis (i.e., the desired focal depth), the angle of each light segment (i.e., the angle information), and the overall energy distribution (i.e., the peak energy distribution information, such as Figure 6 The focusing element's lens profile (i.e., the second profile) is calculated based on the output results (i.e., the desired focal depth, angle information, and peak energy distribution) and the input flat-top beam diameter and energy distribution (i.e., the flat-top beam diameter information and the second beam energy distribution information), with reference to the shaping element's design approach. Through its unique profile design, the focusing element can converge a flat-top beam into a highly energy-efficient and uniform filamentary beam.

[0099] Optionally, the face shape formulas corresponding to the first face shape and the second face shape are:

[0100]

[0101] Where z is the height of the aspheric surface under fixed Y, Y is the distance from the center of the lens plane to any horizontal direction, R, k, A4, A6, A8, A 10 、A 12 、A 14 、A 16 is the surface parameter.

[0102] The face parameter values ​​corresponding to the first face shape and the second face shape are different (that is, the first face parameter value is different from the second face parameter value). The face parameter values ​​can be solved through the above process, so that the Y values ​​under different Y conditions can be obtained using the above face formula, that is, the corresponding first face shape and second face shape are obtained.

[0103] The following describes the application of the filament cutting head using sapphire as an example. The filament cutting head designed in the embodiment of the present invention can be used for cutting sapphire with ink. Usually, a layer of ink is attached to the surface or bottom of the sapphire. It is necessary to maintain the ink removal width while cutting through the sapphire. Figure 7 As shown (different colors represent different energy levels), the brightest, most intense spot in the center is the zero-order light, used for sapphire cutting. The annular area surrounding the zero-order beam represents the sidelobe energy, used for sapphire ink removal. For example, when the filamentation beam strikes the top surface of the sapphire at a distance of Z0.3mm, the distance from the cutting point to the ink edge is 55µm (µm in this article refers to micrometers), meaning a 55µm-wide strip of ink is removed. Similarly, at Z0.4mm, a 40µm-wide strip of ink is removed, and at Z0.5mm, a 25µm-wide strip of ink is removed.

[0104] The laser cutting system and filament cutting head design method provided in this embodiment have the same implementation principles and technical effects as those of the aforementioned filament cutting head embodiment. For the sake of brief description, for matters not mentioned in the embodiments of the laser cutting system and filament cutting head design method, reference may be made to the corresponding contents in the aforementioned filament cutting head embodiment.

[0105] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0106] In addition, in the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0107] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A filament cutting head, characterized in that: It includes a shaping element, a collimating element and a focusing element which are sequentially arranged along the propagation direction of light; The shaping element is an aspherical lens; the shaping element has a first surface shape for converting an input non-top-hat beam into an output top-hat beam; the first surface shape is determined based on first beam energy distribution information on an input surface of the shaping element, as well as desired beam propagation distance and desired top-hat beam energy distribution information; The collimating element is used to collimate the input flat-top beam; the distance between the collimating element and the shaping element is consistent with the desired beam propagation distance; The focusing element is an aspherical lens; the focusing element has a second surface shape, which is used to converge the collimated flat-top beam into a target filamentary beam; the second surface shape is determined based on the flat-top beam diameter information and the second beam energy distribution information on the input surface of the focusing element, as well as the desired focal depth and the peak energy distribution information along the optical axis within the focal depth range; The filament cutting head further comprises a controller, a beam analyzer and a transmission device; the beam analyzer and the transmission device are respectively connected to the controller; The beam profiler is used to detect beam quality information within the focal depth range of the focusing element and send the information to the controller; wherein the beam quality information includes spot energy distribution information; The controller is configured to control the transmission device to adjust the distance between the shaping element and the collimating element based on the received light spot energy distribution information; The controller is further configured to compare the received light spot energy distribution information with preset standard energy distribution information for consistency, and divide the focus area and the peripheral area when calculating the deviation value between the received light spot energy distribution information and the standard energy distribution information.

2. The filament cutting head according to claim 1, characterized in that The controller is further configured to send an adjustment instruction to the transmission device when the comparison result is inconsistent; The transmission device is used to drive the shaping element to move when receiving the adjustment instruction, so as to adjust the distance between the shaping element and the collimating element.

3. The filament cutting head according to claim 1, characterized in that The transmission device includes a fixed seat, a motor, a crank-connecting rod mechanism, a mirror seat and a guide rail; The motor and the guide rail are fixed on the fixed seat, the mirror base is slidably connected to the guide rail, and the mirror base is used to install the shaping element and / or the collimating element; the motor is connected to the mirror base through the crank-connecting rod mechanism, driving the mirror base to slide on the guide rail.

4. The filament cutting head according to any one of claims 1 to 3, characterized in that: The beam quality information also includes spot size information and focal depth information; the controller is further configured to detect the quality of the filament cutting head based on the received spot size information and focal depth information.

5. A laser cutting system, characterized in that: The invention comprises a laser and the filament cutting head according to any one of claims 1 to 4; the laser emits a laser beam toward the filament cutting head.

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