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

Abstract

The invention provides a filamentation cutting head, a laser cutting system and a filamentation cutting head design method, and relates to the technical field of laser control, and the filamentation cutting head comprises a shaping element, a collimating element and a focusing element which are sequentially arranged in the light propagation direction; a laser beam emitted by a laser is converted into a flat-topped beam through a shaping element with a first surface type, the divergence angle of the flat-topped beam is controlled through collimation of a collimation element, finally, the flat-topped beam is converged into a target filamentation beam with high energy utilization rate and high uniformity through a focusing element with a second surface type, and the filamentation beam can realize laser cutting of hard and brittle materials. The processing effect is improved; meanwhile, the filamentation cutting head adopts a total refraction element, not only has the advantages of simple design method, low lens processing difficulty and capability of coping with various materials, but also can convert all Gaussian beams into flat-topped beams and utilize all input energy to filamentation beams.

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, most of the materials used in electronic product panels are hard and brittle materials, such as sapphire, glass, and ceramics. The hard and brittle materials of different electronic products vary in thickness and thickness, and require appropriate and controllable processing methods to process them, which brings challenges to the hard and brittle material processing industry.

[0003] In the prior art, when laser is used to cut hard and brittle materials, the spot size and focal depth range at the focused 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 object of the present invention is to provide a filament cutting head, a laser cutting system and a filament cutting head design method to achieve a filament beam with high energy utilization and high uniformity 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 arranged in sequence along a propagation direction of light;

[0006] The shaping element is an aspherical lens; the shaping element has a first surface shape, which is used to convert an input non-top-beam into an output top-beam; 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 top-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 also includes 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 analyzer 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 also used 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] Further, 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 fixing seat, the mirror seat is slidably connected to the guide rail, and the mirror seat is used to install the shaping element and / or the collimating element; the motor is connected to the mirror seat through a crank connecting rod mechanism to drive the mirror seat 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 used 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] Acquire 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 expected beam propagation distance and expected flat-top beam energy distribution information; 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 expected 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] According to the design data of the focusing element, the second surface shape of the focusing element is determined.

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

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

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

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

[0026] Determine the angle information between a plurality of outgoing light rays in the output light beam of the 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 a matrix form; the surface shape formula corresponding to the first surface shape and the second surface shape is:

[0029]

[0030] Where z is the height of the aspheric surface at a 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 an 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 of a collimating element, and finally converged by a focusing element into a target filamentary beam with high energy utilization and high uniformity. This filamentary beam can realize laser cutting of hard and brittle materials and improve the processing effect. At the same time, the filamentary cutting head adopts a fully 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 use all the input energy for the filamentary beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying 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 diagram of the structure 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 flat-top effect of converting a Gaussian beam into a flat-top 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 technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The laser cutting head used for cutting hard and brittle products in the prior art mainly uses diffraction optical theory and polarization / diffraction optical elements to make the Gaussian beam pass through an axicon-like system, and then form an axial beam with a desired focal depth and energy distribution by a focusing objective lens. Among them, the first lens is a polarization element, which is used to adjust the polarization state of the beam; the second lens is a diffraction element, which obtains the desired spot state by receiving a fixed polarization state; the third lens is a focusing objective lens, which focuses the beam into an axial beam with a 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 manufacturing process of diffraction optical elements, the 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 designed and manufactured based on polarization optics often conflicts with it. 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, the embodiments of the present invention provide a filament cutting head, a laser cutting system and a filament cutting head design method. The filament cutting head is composed of 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 use all input energy in the filament beam to obtain a filament beam with high energy utilization and high uniformity. This filament beam is suitable for laser cutting of hard and brittle materials such as sapphire, and can improve the processing effect of hard and brittle materials.

[0045] It should be noted that the above-mentioned hard and brittle material is not limited to sapphire, but may also be glass, ceramic 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 which are sequentially arranged along the propagation direction of light.

[0048] The shaping element 101 is an aspherical lens; the shaping element 101 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 101, as well as the expected beam propagation distance and the expected flat top beam energy distribution information. The input non-flat top beam can be, but is not limited to, a Gaussian beam, which can be emitted by an ultrafast laser, such as an infrared laser to generate 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 a matrix form. The first beam energy distribution information, the expected beam propagation distance and the expected flat top 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. The consistency 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 the 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 the plano-convex lens has a lower cost.

[0050] The focusing element 103 is an aspherical lens; the focusing element 103 has a second surface type, which is used to converge the collimated flat-top beam into a target filamentary beam; the second surface type 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 103, as well as the expected focal depth and the peak energy distribution information along the optical axis within the focal depth range. The focal depth refers to the front-to-back distance that the lens can focus on while maintaining acceptable clarity. The focal depth range refers to the distance range from the nearest clear point to the farthest clear point. The flat-top beam diameter information, the second beam energy distribution information, the expected focal depth and the peak energy distribution information are all preset by the user, wherein the flat-top beam diameter information and the second beam energy distribution information correspond to the expected flat-top beam energy distribution information, and can be determined by the expected flat-top beam energy distribution information and the beam conversion relationship corresponding to the 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 drawing 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, which is convenient for the installation of the focusing element 103 and the collimating element 102 and also for drawing 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, so that the quality of the output filamentary light beam can be guaranteed.

[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 passing a certain distance (i.e., the expected 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 embodiment of the present invention lie in the performance characteristics and usage methods of the three elements. The shaping element 101 can transform 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 transform the beam entering the focusing element 103 into a collimated beam; the focusing element 103 plays a converging role, and finally forms 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 of the collimating 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 collimating 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 use all the input energy for the filamentation beam.

[0056] Optionally, the filament cutting head further includes a controller, a beam analyzer and a transmission device; the beam analyzer and the transmission device are respectively connected to the controller; the beam analyzer is used to detect the beam quality information within the focal depth range of the focusing element 103 and send it to the controller; wherein the beam quality information includes the 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. In this way, the automatic adjustment of the target filament beam is realized, and the quality of the target filament beam is ensured.

[0057] The above-mentioned beam analyzer can be set at the working distance of the filament cutting head, that is, at the focal position. The beam analyzer can detect the spot energy distribution and spot size at the position, and can also detect the focal depth, etc. The spot energy distribution information output by the beam analyzer can be used to adjust the distance between the shaping element 101 and the collimating element 102, and the spot size information and focal depth information can be used to determine whether the quality of the filament cutting head is qualified.

[0058] The transmission device can drive the shaping element 101 and / or the collimating element 102 to move under the control of the controller to adjust the distance between the shaping element 101 and the collimating element 102. Preferably, the transmission device drives the shaping element 101 to move to adjust the distance between the shaping element 101 and the collimating element 102, so that there is no need to adjust the focusing element 103 subsequently, and this adjustment method is simple and fast.

[0059] In a 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, and when the comparison result is inconsistent, send an adjustment instruction 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 collimation element 102.

[0060] In specific implementation, the consistency comparison process can be as follows: first calculate the deviation between the received spot energy distribution information and the standard energy distribution information to obtain the energy distribution deviation value; then determine whether the energy distribution deviation value is less than a preset energy deviation threshold value, if it is less than, determine that the comparison result is consistent; otherwise, if it is not less than, determine that the comparison result is inconsistent. Among them, the energy deviation threshold value can be set according to 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 Represents 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 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 square 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 focal 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 in 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, wherein 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 above beam quality information also includes spot size information and focal depth information; the controller is further used to detect the quality of the filament cutting head based on the received spot size information and focal depth information, thereby realizing automatic detection of the quality of the filament cutting head.

[0079] In specific implementation, the quality detection process of the filament cutting head can be as follows: first calculate the deviation between the spot size information and the standard spot size, and 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 give an alarm when the quality of the wire cutting head is unqualified, such as giving an alarm through 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 reminded 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 above-mentioned 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, Figure 2 As shown, a beam expander 202 and a reflector 203 are also 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 a filament beam output in a specified direction.

[0084] The embodiment of the present invention also 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 capability. Figure 3 The schematic diagram of a flow chart 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, obtaining 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 light beam energy distribution information may include the energy intensity of the Gaussian light beam at each position expressed in a matrix form.

[0088] Step S320, determining the 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 a plurality of preset first surface shape parameters.

[0090] Among them, the first surface parameter may include the radius of curvature and the quadratic surface coefficient, etc. In specific implementation, optical design software (such as Matlab and Zemax, etc.) can be used to design the shaping element and verify the effect. The shape of the shaping element can be represented by a polynomial function with the first surface parameter, such as Zernike polynomial; ray tracing software (such as Zemax) can be used to simulate the distribution of the light beam after passing through the aspheric lens, and the first surface parameter can be adjusted until the expected flat-top beam distribution is achieved. It should be noted that the 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 the 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 determined first 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 light 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 ray and the optical axis. Then, similar to the surface design method of the shaping element, ray tracing can be performed through optical design software to adjust the second surface parameters 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 to finally form 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 hard and brittle material cutting.

[0096] In a 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 expected beam propagation distance (i.e., the expected 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 expected flat-top beam energy distribution information). Subsequently, the surface shape of the shaping element (i.e., the first surface shape) is reversely inferred based on the Gaussian beam matrix, beam propagation distance, and flat-top beam matrix. When the lens surface shape of the shaping element is confirmed, the expected flat-top beam can be obtained at the collimating element, and the energy of the beam is close to uniform in the entire cross section, such as Figure 4 As shown ( Figure 4 It is obtained by simulation), which makes it easy to obtain 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 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 after passing through the shaping element 101 is compressed to a parallel state after passing through the collimating element 102, and the light beam is flat-top distributed 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 that the energy is relatively consistent). Therefore, 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, the desired focal depth along the Z-axis direction (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 axial peak energy distribution within the focal depth range shown in the figure is calculated by referring to the design method of the shaping element. Based on the output result (i.e., the expected focal depth, angle information, and peak energy distribution information), the input flat-top beam diameter and energy distribution (i.e., the flat-top beam diameter information and the second beam energy distribution information), the lens surface shape (i.e., the second surface shape) of the focusing element is calculated. The focusing element can converge a flat-top beam into a filament beam with high energy utilization and high uniformity through its special surface design.

[0099] Optionally, the face shape formula corresponding to the first face shape and the second face shape is:

[0100]

[0101] Where z is the height of the aspheric surface at a 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 by the above process, so that the above face formula can be used to obtain the Y values ​​under different Ys, that is, to obtain the corresponding first face shape and second face shape.

[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 applied to the cutting of 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 in the figure (different colors represent different energy levels), the brightest and most intense light spot in the center is the 0th order light, which is used for sapphire cutting; the annular area around the 0th order light beam is the sidelobe energy, which is used for sapphire ink removal. For example, when the filamentary light beam acts on the upper surface of the sapphire at Z0.3mm, the width of the cutting point from the ink edge is 55um (um in this article refers to micrometers), which means that 55um of ink is removed; similarly, at Z0.4mm, 40um of ink is removed; at Z0.5mm, 25um of ink is removed.

[0104] The laser cutting system and filament cutting head design method provided in this embodiment have the same implementation principle 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, further definition and explanation thereof is not required in subsequent drawings.

[0106] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to 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", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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 the light; The shaping element is an aspherical lens; the shaping element has a first surface shape, which is used to convert an input non-top-beam into a 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 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 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 expected focal depth and the peak energy distribution information along the optical axis within the focal depth range.

2. The filament cutting head according to claim 1, characterized in that: The filament cutting head also includes a controller, a beam analyzer and a transmission device; the beam analyzer and the transmission device are respectively connected to the controller; The beam analyzer 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; 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.

3. The filament cutting head according to claim 2, characterized in that: The controller is further used to compare the received light 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; 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.

4. The filament cutting head according to claim 2, characterized in that: The transmission device comprises 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 and / or the collimating element; the motor is connected to the mirror seat through the crank-connecting rod mechanism, driving the mirror seat to slide on the guide rail.

5. The filament cutting head according to any one of claims 2 to 4, characterized in that: The beam quality information also includes spot size information and focal depth information; the controller is further used to detect the quality of the filament cutting head based on the received spot size information and the focal depth information.

6. 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 5; the laser emits a laser beam toward the filament cutting head.

7. A method for designing a filament cutting head, characterized in that: The filament cutting head used in any one of claims 1 to 5; the method comprising: Acquire 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 expected beam propagation distance and expected flat-top beam energy distribution information; the focusing element design data includes flat-top beam diameter information and second beam energy distribution information on the input surface of the focusing element, as well as expected focal depth and peak energy distribution information along the optical axis within the focal depth range; Determining a first surface shape of the shaping element according to the shaping element design data; The second surface shape of the focusing element is determined according to the focusing element design data.

8. The method according to claim 7, characterized in that Determining the first surface shape of the shaping element according to the shaping element design data includes: Determining third beam energy distribution information on the output surface of the shaping element according to the desired beam propagation distance and the desired flat-top beam energy distribution information; The first surface shape of the shaping element is determined according to the third light beam energy distribution information, the first light beam energy distribution information and a plurality of preset first surface shape parameters.

9. The method according to claim 7, characterized in that: Determining the second surface shape of the focusing element according to the focusing element design data includes: Determining angle information between a plurality of outgoing light rays in an output light beam of the focusing element and an optical axis according to the desired focal depth and the peak energy distribution information; 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.

10. The method according to any one of claims 7 to 9, characterized in that: The first beam energy distribution information includes the energy intensity of the Gaussian beam at each position represented in matrix form; the surface shape formula corresponding to the first surface shape and the second surface shape is: Where z is the height of the aspheric surface at a 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.

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