3D printing apparatus and light source therefor

Abstract

The application discloses a 3D printing device and a light source thereof, and relates to the technical field of 3D printing devices, and aims to improve printing efficiency and printing precision. The device comprises a laser array and a diffraction element array arranged correspondingly to the laser array. The laser array comprises n rows and m columns of lasers, and the diffraction elements in the diffraction element array are arranged correspondingly to the lasers. The center line of the diffraction element and the corresponding laser is located on the optical axis of the laser. The laser array is used for emitting n rows and m columns of laser beams, and the diffraction element array is used for adjusting the n rows and m columns of laser beams to be close to the central optical axis of the laser array, so as to form array laser beams without gaps between the laser beams. The deflection angles of the laser beams emitted by the lasers in the laser array which are symmetric to the central optical axis are the same, n and m are positive integers, and n*m>1.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more particularly to a 3D printing device and its light source. Background Technology

[0002] With the advancement of technology and the development of society, 3D printing equipment is being used more and more widely, and people are placing higher demands on its printing quality and efficiency.

[0003] Due to the mechanical assembly process, current 3D printing equipment often results in gaps between the laser spots emitted by laser arrays within the same row. This means that after each scan, gaps remain between the laser spots, preventing the printing of a finished workpiece. Consequently, the laser array position needs to be adjusted, and the machine scans again in the same direction to fill these gaps. However, such frequent adjustments to the laser array position significantly degrade the print quality.

[0004] To address the aforementioned issues, researchers have devised a solution: 3D printing equipment is equipped with two rows of laser arrays, arranged in an alternating pattern. This means the laser spots from the previous row are located within the gaps between the laser spots in the next row, and vice versa. This allows the first laser array to scan first, followed by the second, which introduces a time delay and reduces printing accuracy. Alternatively, scanning both rows simultaneously results in wasted material at the beginning and end of the scan, and requires post-printing trimming, increasing process complexity. Furthermore, the alternating laser arrays increase equipment costs. Summary of the Invention

[0005] This invention provides a 3D printing device and its light source to solve the problem of low printing efficiency and low printing accuracy caused by gaps in the light source of 3D printing devices in related technologies.

[0006] To address the aforementioned problems, one embodiment of the present invention proposes a light source for a 3D printing device, comprising: a laser array, and a diffraction element array corresponding to the laser array; The laser array includes n rows and m columns of lasers. The diffraction elements in the diffraction element array are arranged in a one-to-one correspondence with the lasers. The line connecting the center of the diffraction element and the center of the corresponding laser is located on the optical axis of the laser. The laser array is used to emit n rows and m columns of laser beams, and the diffraction element array is used to adjust the n rows and m columns of laser beams to approach the central optical axis of the laser array, forming an array of laser beams without gaps between each laser beam. The laser beams emitted by the lasers in the laser array that are symmetrical about the central optical axis have the same deflection angle towards the central optical axis, and n and m are positive integers and n×m>1.

[0007] Optionally, when n×m is an odd number, a central laser is provided on the central optical axis of the laser array for emitting a central laser beam, and a central diffraction element corresponding to the central laser is used to collimate the central laser beam; the diffraction elements in the diffraction element array other than the central diffraction element are used to deflect and collimate the laser beams other than the central laser beam in the n rows and m columns of the laser beam.

[0008] Optionally, n=1, m=3, the first row and first column diffraction element is used to deflect the first row and first column laser beam towards the direction of the central laser beam by a first deflection angle and collimate it to form a first adjustment beam, the first row and third column diffraction element is used to deflect the first row and third column laser beam towards the direction of the central laser beam by a second deflection angle and collimate it to form a second adjustment beam; the central diffraction element is used to collimate the central laser beam to form a central adjustment beam; the first adjustment beam, the central adjustment beam, and the second adjustment beam form a line beam; the first deflection angle and the second deflection angle are the same in magnitude.

[0009] Optionally, when n×m is an even number, the n×m diffraction elements in the diffraction element array are used to deflect and collimate the n×m laser beams.

[0010] Optionally, n=2, m=3, the first row and first column diffraction elements are used to deflect the first row and first column laser beam towards the central optical axis by a third deflection angle and collimate it to form a third adjustment beam; the first row and second column diffraction elements are used to deflect the first row and second column laser beam towards the central optical axis by a fourth deflection angle and collimate it to form a fourth adjustment beam; the first row and third column diffraction elements are used to deflect the first row and third column laser beam towards the central optical axis by a fifth deflection angle and collimate it to form a fifth adjustment beam; the second row and first column diffraction elements are used to deflect the second row and first column laser beam towards the central optical axis by a sixth deflection angle and collimate it to form a sixth adjustment beam; the second row and second column diffraction elements are used to deflect the second row and second column laser beam towards the central optical axis by a seventh deflection angle and collimate it to form a seventh adjustment beam; the second row and third column diffraction elements are used to deflect the second row and third column laser beam towards the central optical axis by an eighth deflection angle and collimate it to form an eighth adjustment beam; The third adjustment beam to the eighth adjustment beam form a surface beam; the third deflection angle, the fifth deflection angle, the sixth deflection angle and the eighth deflection angle are the same size, and the fourth deflection angle and the seventh deflection angle are the same size.

[0011] Optionally, the light source of the 3D printing equipment further includes: a microlens array located on the path of the n rows and m columns of laser beam transmission, wherein the microlenses in the microlens array are arranged one-to-one with the laser, and the microlenses are used to collimate the laser beam emitted by the laser to form an n rows and m columns of collimated laser beam; The centers of the microlenses in the microlens array, the centers of the corresponding diffraction elements in the diffraction element array, and the centers of the corresponding lasers in the laser array are located on the same straight line. When n×m is an even number, the diffraction element array is used to deflect the n rows and m columns of collimated laser beams toward the central optical axis of the laser array; when n×m is an odd number, the diffraction element array is used to deflect the other laser beams in the n rows and m columns of collimated laser beams, except for the central laser beam, toward the central laser beam.

[0012] Optionally, the 3D printing equipment light source further includes a beam-shrinking lens located on the path of the array laser beam transmission, for beam-shrinking the array laser beam.

[0013] Optionally, the diffraction element is a diffraction grating or a diffraction superlens structure.

[0014] Optionally, the phase distribution of each diffraction element in the diffraction element array satisfies the following relationship: ; In the formula, ; in, Let be the amplitude function of any laser beam in an n x m laser beam array. This represents the phase distribution of the diffraction elements in the corresponding diffraction element array. This represents the amplitude function of the laser beam in the corresponding array laser beam. The complex amplitude of the incident surface of the diffraction element is given. For wave vector, The distance is the distance from the incident surface of the diffraction element to the image plane of the spot formed by the array laser beam. is the wavelength of the laser beam, where able to pass and It is obtained by performing multiple forward and inverse Fourier transforms.

[0015] To address the aforementioned problems, another embodiment of the present invention provides a 3D printing device, including a light source for the 3D printing device described in any embodiment of the present invention.

[0016] The 3D printing device and its light source proposed in the embodiments of the present invention include: a laser array and a diffraction element array corresponding to the laser array; the laser array includes n rows and m columns of lasers, and the diffraction elements in the diffraction element array are arranged one-to-one with the lasers, with the line connecting the center of the diffraction element and the center of the corresponding laser located on the optical axis of the laser; the laser array is used to emit n rows and m columns of laser beams, and the diffraction element array is used to adjust the n rows and m columns of laser beams to approach the central optical axis of the laser array, forming an array of laser beams without gaps between each laser beam, wherein the laser beams emitted by the lasers symmetrical about the central optical axis in the laser array are deflected at the same angle towards the central optical axis, n and m are positive integers and n×m>1. Thus, by adding a diffraction element array to the light source of the 3D printing device, the array light spot formed by the laser array of the 3D printing device light source breaks through the limitations of mechanical structure assembly, and there are no gaps between the light spots formed by each laser beam, so that a line can be printed in one scan during the printing process without repeated scanning, thereby improving printing efficiency and printing accuracy.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the light source in 3D printing equipment in related technologies; Figure 2 This is a schematic diagram of the light spot on the working surface of the light source of a 3D printing device in related technologies; Figure 3 This is a schematic diagram of the structure of the light source of the 3D printing equipment proposed in the embodiments of the present invention; Figure 4 This is a schematic diagram of the light spot on the working surface of the light source of the 3D printing equipment proposed in this embodiment of the invention; Figure 5 This is a schematic diagram of the structure of the light source of a 3D printing device according to an embodiment of the present invention; Figure 6This is a schematic diagram of the light spot on the working surface of the light source of a 3D printing device according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the optical path principle of the light source of the 3D printing equipment proposed in another embodiment of the present invention; Figure 8 This is a schematic diagram of the light spot on the working surface of the light source of the 3D printing equipment according to another embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the light source of the 3D printing device proposed in another embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of the light source of the 3D printing device proposed in another embodiment of the present invention; Figure 11 This is the light path diagram of the 3D printing equipment light source simulated in software according to the embodiments of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Figure 1 This is a schematic diagram of the light source structure in 3D printing equipment using related technologies. For example... Figure 1 As shown, the light source of this 3D printing equipment includes a 3D printing laser array 1, a collimating microlens array 2, and a working surface 3. The 3D printing laser array 1 is arranged in an alternating pattern. Along the optical path propagation direction, the collimating microlens array 2 corresponds to the alternating pattern of the 3D printing laser array 1, collimating the large-angle beam into a small-angle beam and projecting it onto the working surface 3 of the printing material. Figure 2This is a schematic diagram of the light spot on the working surface of the light source in a 3D printing device. By controlling the switching state of the corresponding laser, the desired printing pattern can be constructed. The mechanical structure controls the movement of the light spot array along the y-direction, completing the construction of a gapless, closed image during the movement.

[0023] However, its problems include, Figure 2 As shown, due to the installation of mechanical structures and fusion structures, the light emitted by the 3D printing laser array 1 is collimated by microlenses to form staggered light spots. During the printing process, to seamlessly connect two rows of light spots into a single line, the mechanical structure needs to move along the y-direction to bring the second row of light spots into contact with the first row, thus completing one line scan. This results in a time delay and affects printing accuracy due to the mechanical movement. If the second row of light spots is not moved using the mechanical structure, two scans are required, or one scan may result in waste material at the beginning and end.

[0024] Therefore, based on the above problems, this invention proposes a 3D printing device and its light source. By setting up a diffraction element array, the mechanical spacing between the light spots in each row can be solved, thereby improving printing efficiency and printing accuracy.

[0025] Figure 3 This is a schematic diagram of the structure of the light source of the 3D printing equipment proposed in the embodiment of the present invention. Figure 4 This is a schematic diagram of the light spot on the working surface of the light source of the 3D printing equipment proposed in an embodiment of the present invention. Figure 3 and Figure 4 As shown, the light source of the 3D printing equipment includes: a laser array 10, and a diffraction element array 20 corresponding to the laser array 10; The laser array 10 includes n rows and m columns of lasers. The diffraction elements in the diffraction element array 20 are arranged in a one-to-one correspondence with the lasers. The line connecting the center of the diffraction element and the center of the corresponding laser is located on the optical axis of the laser. The laser array 10 is used to emit an n-row m-column laser beam, and the diffraction element array 20 is used to adjust the n-row m-column laser beam to approach the central optical axis of the laser array 10, forming an array laser beam without gaps between the laser beams. The laser beams emitted by the lasers in the laser array 10 that are symmetrical about the central optical axis have the same deflection angle towards the central optical axis. n and m are positive integers and n×m>1.

[0026] It is understood that the laser array 10 includes at least two lasers, meaning that n×m>1, or at least m=2 when n=1, or m=1 when n=2. Each laser can be composed of a single-point emission aperture or an array of emission apertures, radiating optical power from a few milliwatts to a few watts. Furthermore, for different printing materials, the laser wavelength can be selected from a specific wavelength between 380-1100nm suitable for the material's reaction. For example, for nylon materials, a laser with a wavelength of 808-1064nm, such as a 940nm near-infrared continuous laser, can be selected. The diffraction element array 20 is arranged in the direction of the light emitted from the laser array 10, with the center of each laser aligned with the center of the diffraction element to avoid beam distortion. The surface of the diffraction element is composed of many micro / nano structures, which can be fabricated using nanoimprinting, direct laser beam writing, or photolithography.

[0027] For example, such as Figure 3 and Figure 4 As shown, taking n=1 and m=2 as an example, the lasers in the light source are arranged in one row and two columns. The laser array 10 includes a first laser 101 and a second laser 102, and the diffraction element array 20 includes a first diffraction element 201 and a second diffraction element 202. The first laser 101 is correspondingly positioned with the first diffraction element 201, and the second laser 102 is correspondingly positioned with the second diffraction element 202. The central optical axis of the laser array 10 is A. The first laser 101 emits a first laser beam, and the second laser 102 emits a second laser beam. The first laser beam is deflected towards the central optical axis A by the first diffraction element 201, and the second laser beam is deflected towards the central optical axis A by the second diffraction element 202. This ensures that there is no gap between the first and second laser beams forming a spot on the working surface 30. In this configuration, the first laser 101 and the second laser 102 are symmetrically arranged around the central optical axis A. The deflection angle of the first laser beam towards the central optical axis A is the same as that of the second laser beam. This is beneficial for the design of the diffraction element.

[0028] It should be noted that in this embodiment, a corresponding diffraction element is set along the path of the laser beam emitted by each laser. The required diffraction angle of the diffraction element is calculated through optical path simulation, so that the transmission direction of the laser beam is deflected to a certain extent after passing through the diffraction element. Therefore, when the laser beam reaches the working surface 30°, there is no gap between the spot formed by this laser beam and the spot formed by the laser beam emitted by other lasers, thus forming a line spot. Therefore, when a straight line along the y-direction needs to be formed in practice, only one row of lasers needs to be set in the light source, and the movement of one row of lasers along the y-direction can be directly controlled by a mechanical structure. In this embodiment, by setting one row of lasers and one row of diffraction elements, the gap of the spot on the working surface and the related problems caused by the gap can be solved in related technologies. Since the target pattern can be completed in one scan, and there is no waste at the beginning and end of the pattern, not only is the printing efficiency and printing quality improved, but the number of lasers is also reduced, thus reducing equipment costs.

[0029] In one embodiment, the diffraction element can simultaneously deflect and collimate the laser beam.

[0030] Optionally, when n×m is an odd number, a central laser is provided on the central optical axis of the laser array 10 to emit a central laser beam, and a central diffraction element corresponding to the central laser is used to collimate the central laser beam; the diffraction elements in the diffraction element array 20 other than the central diffraction element are used to deflect and collimate the laser beams other than the central laser beam in the n rows and m columns of laser beams.

[0031] It should be noted that when n×m is an odd number, a central laser is placed on the central optical axis of the laser array 10. Thus, the diffraction element array 20 can bring all laser beams in the laser array 10, except for the central laser beam, closer to the central laser beam, collimating and deflecting the other laser beams and collimating the central laser beam. This reduces the divergence angle of each laser beam, resulting in a higher intensity spot on the working surface 30. The deflection angle and collimation effect of the diffraction elements on the beam can be predicted in advance through optical path simulation, and a suitable diffraction element structure can be designed using the corresponding diffraction element design method (GS algorithm).

[0032] Optionally, Figure 5 This is a schematic diagram of the structure of the light source of a 3D printing device proposed in one embodiment of the present invention. Figure 6This is a schematic diagram of the light spot on the working surface of the light source of a 3D printing device according to an embodiment of the present invention. n=1, m=3. The first row and first column diffraction element is used to deflect the first row and first column laser beam towards the direction of the central laser beam at a first deflection angle and collimate it to form a first adjustment beam. The first row and third column diffraction element is used to deflect the first row and third column laser beam towards the direction of the central laser beam at a second deflection angle and collimate it to form a second adjustment beam. The central diffraction element is used to collimate the central laser beam to form a central adjustment beam. The first adjustment beam, the central adjustment beam, and the second adjustment beam form a line beam. The first deflection angle and the second deflection angle are the same size.

[0033] like Figure 5 and Figure 6 As shown, the laser array 10 includes a first laser 101, a second laser 102, and a central laser 103. The diffraction element array 20 includes a first diffraction element 201, a second diffraction element 202, and a central diffraction element 203. The central diffraction element 203 is used to collimate the central laser beam emitted from the central laser 103. The first diffraction element 201 is used to deflect and collimate the first laser beam emitted from the first laser 101. The second diffraction element 202 is used to deflect and collimate the second laser beam emitted from the second laser 102. This ensures that the first laser beam, after passing through the first diffraction element 201, is deflected closer to the central laser beam, and the second laser beam, after passing through the second diffraction element 202, is also deflected closer to the central laser beam. Thus, the three laser beams form a seamless line spot (e.g., ...) on the working surface 30. Figure 6 (As shown).

[0034] In this embodiment, Figure 5 The arrangement interval b between the three lasers is 0.3 mm, and the side length c of each laser is 0.5 mm. Each laser has a corresponding diffraction element covering its front optical path. The diffraction element has a side length of 0.6 mm and a thickness of 0.15 mm, slightly larger than the laser surface to prevent light leakage. The distance d from the diffraction element to the working surface is 3 mm. When light passes through the diffraction element, it is deflected at an angle of arctan((b+c)÷2÷d). The first deflection angle is 7.59 degrees, and similarly, the second deflection angle is -7.59 degrees. The distance a from the center of the laser array 10 to the center of the diffraction element 20 is approximately equal to the focal length f of the diffraction element. The diffraction efficiency of the diffraction element is greater than 80%, resulting in high light utilization.

[0035] Optionally, when n×m is an even number, the n×m diffraction elements in the diffraction element array 20 are used to deflect and collimate the n×m laser beams.

[0036] In other words, when n×m is an even number, each diffraction element plays a role in deflecting and collimating the corresponding laser beam.

[0037] Optionally, Figure 7 This is a schematic diagram of the optical path principle of the light source of the 3D printing equipment proposed in another embodiment of the present invention. Figure 8 This is a schematic diagram of the light spot on the working surface of the light source of a 3D printing device according to another embodiment of the present invention. n=2, m=3. The first row and first column diffraction element is used to deflect the first row and first column laser beam towards the central optical axis by a third deflection angle and collimate it to form a third adjustment beam. The first row and second column diffraction element is used to deflect the first row and second column laser beam towards the central optical axis by a fourth deflection angle and collimate it to form a fourth adjustment beam. The first row and third column diffraction element is used to deflect the first row and third column laser beam towards the central optical axis by a fifth deflection angle and collimate it to form a fifth adjustment beam. The second row and first column diffraction element is used to deflect the second row and first column laser beam towards the central optical axis by a sixth deflection angle and collimate it to form a sixth adjustment beam. The second row and second column diffraction element is used to deflect the second row and second column laser beam towards the central optical axis by a seventh deflection angle and collimate it to form a seventh adjustment beam. The second row and third column diffraction element is used to deflect the second row and third column laser beam towards the central optical axis by an eighth deflection angle and collimate it to form an eighth adjustment beam. The third to the eighth adjustment beams form a surface beam; the third, fifth, sixth and eighth deflection angles are the same size, and the fourth and seventh deflection angles are the same size.

[0038] like Figure 7 and Figure 8 As shown, the laser array 10 includes two rows and three columns of lasers, namely the laser at position (1,1), the laser at position (1,2), the laser at position (1,3), the laser at position (2,1), the laser at position (2,2), and the laser at position (2,3). The asterisk (*,*) does not represent actual coordinate data, but rather the row and column number.

[0039] Similarly, the diffraction element array 20 is also arranged in the positions described above. Thus, the diffraction elements located at positions (1,1), (1,3), (2,1), and (2,3) can deflect and collimate the laser beam output from the corresponding laser, bringing it closer to the central optical axis A. Furthermore, the deflection angles are all the same and are solid angles, meaning there is deflection in both the x and y directions. The diffraction elements located at positions (1,2) and (2,2) can deflect and collimate the laser beam output from the corresponding laser, bringing it closer to the central optical axis A. Furthermore, the deflection angles are all the same, meaning there is deflection in the y direction. Finally, the light spot formed on the working surface 30 is as follows... Figure 8 As shown, this forms a surface light spot.

[0040] In another embodiment, the diffraction elements in the diffraction element array 20 deflect the laser beam.

[0041] Optionally, Figure 9 This is a schematic diagram of the structure of a 3D printing device light source according to another embodiment of the present invention. The 3D printing device light source further includes: a microlens array 40, located on the path of the n rows and m columns of laser beam transmission. The microlenses in the microlens array 40 are arranged one-to-one with the laser, and the microlenses are used to collimate the laser beam emitted by the laser to form an n rows and m columns of collimated laser beam; The centers of the microlenses in the microlens array 40, the centers of the corresponding diffraction elements in the diffraction element array 20, and the centers of the corresponding lasers in the laser array 10 are located on the same straight line. When n×m is an even number, the diffraction element array 20 is used to deflect the collimated laser beam in n rows and m columns toward the central optical axis of the laser array 10; when n×m is an arbitrary number, the diffraction element array 20 is used to deflect the other laser beams in the collimated laser beam in n rows and m columns, except for the central laser beam, toward the central laser beam.

[0042] In other words, in this embodiment, the microlens array 40 collimates the laser beam, and the diffraction element array 20 deflects the laser beam collimated by the microlens array 40. Thus, although the microlens array 40 is added, the complexity of designing the diffraction element array 20 is reduced. The diffraction element array 20 only deflects the laser beam.

[0043] It should be noted that an example of how the diffraction element 20 deflects the laser beam can be found in the previous embodiment. Figures 5 to 8 The details will not be repeated here.

[0044] Optionally, Figure 10 This is a schematic diagram of the structure of a 3D printing equipment light source according to another embodiment of the present invention. The 3D printing equipment light source further includes: a beam-shrinking lens 50, located on the path of the array laser beam transmission, used to shrink the array laser beam.

[0045] The beam-shrinking lens 50 can shrink the light beam adjusted by the diffraction element array 20, providing higher optical power density and resolution. Therefore, by adding the beam-shrinking lens 50 to the aforementioned embodiment, the beam-shrinking lens 50 can reduce the light spot array on the working surface 30 to a smaller light spot array, improving optical power density and resolution, and achieving faster and higher precision printing.

[0046] The beam-shrinking lens 50 may include at least one focusing lens, and in other embodiments may be a cemented lens formed by at least two lenses, etc., which is not specifically limited by the present invention. For example, the beam-shrinking lens 50 may, in the negative z-axis direction, sequentially include a first lens with positive optical power, a second lens with negative optical power, an aperture stop, a third lens with positive optical power, and a fourth lens with negative optical power.

[0047] Optionally, the diffraction element is a diffraction grating or a diffraction superlens structure.

[0048] Among them, the surface of the diffractive superlens structure consists of tiny columnar structures or tooth-like structures.

[0049] Optionally, the phase distribution of each diffraction element in the diffraction element array satisfies the following relationship: ; In the formula, ; in, Let be the amplitude function of any laser beam in an n x m laser beam array. This represents the phase distribution of the diffraction elements in the corresponding diffraction element array. This represents the amplitude function of the laser beam in the corresponding array laser beam. The complex amplitude of the incident surface of the diffraction element. For wave vector, is the distance from the incident surface of the diffraction element to the image plane of the spot formed by the array laser beam. is the wavelength of the laser beam, where able to pass and It is obtained by performing multiple forward and inverse Fourier transforms.

[0050] Specifically, the GS algorithm obtains the phase distribution of the diffraction element as follows, using the input light field. With output light field The forward and inverse Fourier transforms between the input and output surfaces, as well as the light field constraints on the input and output surfaces, are iterated repeatedly until the design requirements are met.

[0051] Where, take any The initial phase distribution of the incident surface, which serves as the diffraction element, is related to the incident light amplitude. By combining these, the complex amplitude of the incident light surface can be obtained. . In the formula and the following content Let this be the number of iterations. The complex amplitude is obtained by performing a Fourier transform from the input surface to the output surface. FFT stands for Fourier Transform.

[0052] .Pick phase function The target amplitude function obtained from the diffraction surface By combining these, a new light field distribution function is obtained. At this point, k = k + 1, for Performing the inverse Fourier transform, we obtain iFFT stands for Inverse Fourier Transform.

[0053] , , will get The second phase distribution at the incident surface, which serves as a diffraction element, is related to the incident light amplitude. Combining these steps, the algorithm returns to the initial steps. It stops when the mean square error (SSE) is less than a preset value ε or the number of iterations reaches the maximum number of iterations M, thus obtaining the diffraction phase distribution of the diffraction element. Therefore, the structure of the diffraction element can be designed based on its diffraction phase distribution.

[0054] in, Figure 11 This is the optical path diagram simulated in software by the light source of the 3D printing equipment proposed in this embodiment of the invention. For example... Figure 11 As shown, the distance between laser AA and laser BB is 1 mm, the distance between laser BB and laser CC is 1 mm, the distance H1 from the light-emitting surface of the laser array to the diffraction element array DD is 5 mm, the distance H2 from the diffraction element array DD to the imaging surface FF is 10 mm, the deflection angle of the center light emitted from laser BB is 0 degrees, the deflection angle of the light emitted from laser AA is 2.86 degrees, and the deflection angle of the light emitted from laser CC is -2.86 degrees.

[0055] Another embodiment of the present invention provides a 3D printing device, including a 3D printing device light source as described in any embodiment of the present invention. This device has the corresponding beneficial effects of the foregoing embodiments.

[0056] This device, utilizing electromagnetic radiation, selectively cures building materials layer by layer to create three-dimensional objects at positions corresponding to the cross-sections of the layers of the object to be manufactured. The device includes a radiation source suitable for emitting electromagnetic radiation, diffraction elements for shaping the beam emitted by the radiation source, and the shaped beam illuminating the material surface, thus curing the building material on the working surface. The radiation source includes at least two semiconductor lasers, and an array of diffraction elements is arranged along the propagation direction of the laser array, with each diffraction element aligned with the center of its corresponding laser. The diffraction elements not only convert large-angle light emitted by the radiation source into small-angle light, but also deflect the light to the corresponding imaging position through diffraction, illuminating the material on the working surface and constructing the printed object layer by layer.

[0057] Compared to existing microlens arrays that only collimate the light beam, this invention uses a diffraction element array, which not only collimates the beam but also deflects the light at a specific angle, eliminating the problem of gaps in the light spot. Therefore, during the printing process, there is no need for mechanical movement to compensate for misalignments, allowing for direct linear formation. This eliminates both time delays and the impact of mechanical movement on accuracy, improving both printing speed and forming precision.

[0058] In summary, the 3D printing equipment and its light source proposed in the embodiments of the present invention include: a laser array and a diffraction element array corresponding to the laser array; the laser array includes n rows and m columns of lasers, and the diffraction elements in the diffraction element array are arranged one-to-one with the lasers, with the line connecting the center of the diffraction element and the center of the corresponding laser located on the optical axis of the laser; the laser array is used to emit n rows and m columns of laser beams, and the diffraction element array is used to adjust the n rows and m columns of laser beams to approach the central optical axis of the laser array, forming an array of laser beams without gaps between each laser beam, wherein the laser beams emitted by the lasers symmetrical about the central optical axis in the laser array are deflected at the same angle towards the central optical axis, n and m are positive integers and n×m>1. Thus, by adding a diffraction element array to the light source of the 3D printing equipment, the array light spot formed by the laser array of the 3D printing equipment light source breaks through the limitations of mechanical structure assembly, and there are no gaps between the light spots formed by each laser beam, so that a line can be printed in one scan during the printing process without repeated scanning, thereby improving printing efficiency and printing accuracy.

[0059] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A light source for a 3D printing device, characterized in that, include: A laser array, and a diffraction element array corresponding to the laser array; The laser array includes n rows and m columns of lasers. The diffraction elements in the diffraction element array are arranged in a one-to-one correspondence with the lasers. The line connecting the center of the diffraction element and the center of the corresponding laser is located on the optical axis of the laser. The laser array is used to emit n rows and m columns of laser beams. The diffraction element array is used to adjust the n rows and m columns of laser beams to approach the central optical axis of the laser array, forming an array of laser beams without gaps between them. The laser beams emitted by the lasers in the laser array that are symmetrical about the central optical axis have the same deflection angle towards the central optical axis. n and m are positive integers and n×m>1. When n×m is odd, a central laser is positioned on the central optical axis of the laser array to emit a central laser beam, and a central diffraction element corresponding to the central laser is used to collimate the central laser beam. The diffraction elements in the diffraction element array, excluding the central diffraction element, are used to deflect and collimate the laser beams in the n rows and m columns other than the central laser beam. When n×m is even, the n×m diffraction elements in the diffraction element array are used to deflect and collimate n×m laser beams.

2. The light source of the 3D printing equipment according to claim 1, characterized in that, With n=1 and m=3, the first row and first column diffraction element is used to deflect the first row and first column laser beam towards the direction of the central laser beam by a first deflection angle and collimate it to form a first adjustment beam. The first row and third column diffraction element is used to deflect the first row and third column laser beam towards the direction of the central laser beam by a second deflection angle and collimate it to form a second adjustment beam. The central diffraction element is used to collimate the central laser beam to form a central adjustment beam. The first adjustment beam, the central adjustment beam, and the second adjustment beam form a line beam. The first deflection angle and the second deflection angle are the same in magnitude.

3. The light source of the 3D printing equipment according to claim 1, characterized in that, With n=2 and m=3, the first row and first column diffraction element deflects the laser beam in the first row and first column towards the central optical axis by a third deflection angle and collimates it to form a third adjustment beam. The first row and second column diffraction element deflects the laser beam in the first row and second column towards the central optical axis by a fourth deflection angle and collimates it to form a fourth adjustment beam. The first row and third column diffraction element deflects the laser beam in the first row and third column towards the central optical axis by a fifth deflection angle and collimates it to form a fifth adjustment beam. The second row and first column diffraction element deflects the laser beam in the second row and first column towards the central optical axis by a sixth deflection angle and collimates it to form a sixth adjustment beam. The second row and second column diffraction element deflects the laser beam in the second row and second column towards the central optical axis by a seventh deflection angle and collimates it to form a seventh adjustment beam. The second row and third column diffraction element deflects the laser beam in the second row and third column towards the central optical axis by an eighth deflection angle and collimates it to form an eighth adjustment beam. The third adjustment beam to the eighth adjustment beam form a surface beam; the third deflection angle, the fifth deflection angle, the sixth deflection angle and the eighth deflection angle are the same size, and the fourth deflection angle and the seventh deflection angle are the same size.

4. The light source of the 3D printing equipment according to claim 1, characterized in that, Also includes: A microlens array is located on the path of the n rows and m columns of laser beam transmission. The microlenses in the microlens array are arranged one-to-one with the laser. The microlenses are used to collimate the laser beam emitted by the laser to form an n rows and m columns of collimated laser beam. The centers of the microlenses in the microlens array, the centers of the corresponding diffraction elements in the diffraction element array, and the centers of the corresponding lasers in the laser array are located on the same straight line. When n×m is an even number, the diffraction element array is used to deflect the n-row m-column collimated laser beam toward the central optical axis of the laser array; When n×m is an odd number, the diffraction element array is used to deflect the other laser beams in the n-row m-column collimated laser beam, excluding the central laser beam, toward the central laser beam.

5. The light source of the 3D printing equipment according to claim 1 or 4, characterized in that, Also includes: A beam-shrinking lens, located on the path of the array laser beam transmission, is used to shrink the array laser beam.

6. The light source of the 3D printing equipment according to claim 1, characterized in that, The diffraction element is a diffraction grating or a diffraction superlens structure.

7. The light source of the 3D printing equipment according to claim 1, characterized in that, The phase distribution of each diffraction element in the diffraction element array satisfies the following relationship: ； In the formula, ; in, Let be the amplitude function of any laser beam in an n x m laser beam array. This represents the phase distribution of the diffraction elements in the corresponding diffraction element array. This represents the amplitude function of the laser beam in the corresponding array laser beam. The complex amplitude of the incident surface of the diffraction element is given. For wave vector, The distance is the distance from the incident surface of the diffraction element to the image plane of the spot formed by the array laser beam. is the wavelength of the laser beam, where able to pass and The positive and inverse Fourier transform methods that satisfy the conditions between are obtained iteratively.

8. A 3D printing device, characterized in that, Includes the 3D printing equipment light source as described in any one of claims 1-7.

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