Manufacturing method for high-aspect-ratio x-ray grating, and high-aspect-ratio x-ray grating

Abstract

The present application provides a manufacturing method for a high-aspect-ratio X-ray grating. The grating comprises m first material portions (100) and n second material portions (200), wherein -1≤m-n≤1, and m and n are both positive integers. The manufacturing method comprises alternately stacking the first material portions (100) and the second material portions (200). The present application further provides a high-aspect-ratio X-ray grating, wherein the grating has a height direction (A) and a cycle direction (B) which are perpendicular to each other; and in a plane formed by the height direction (A) and the cycle direction (B), the height of the grating is h, the grating further comprises first edges (300) and second edges (400) which are parallel to the cycle direction (B), wherein the length of the first edges (300) is D1, the length of the second edges (400) is D2, D1≤D2, and h(m+n) / D1>200.

Description

Manufacturing method of high aspect ratio X-ray grating and high aspect ratio X-ray grating Citation of Related Applications This application claims priority to a prior invention patent application filed in China with application date April 3, 2024, application number 202410405004.1, and invention name “Method for manufacturing high aspect ratio X-ray grating and high aspect ratio X-ray grating”. The entire contents of the prior application are incorporated herein by reference. Technical Field The present application relates to the field of X-ray multi-characteristic imaging, and in particular to a method for manufacturing a high aspect ratio X-ray grating and a high aspect ratio X-ray grating. Background Art As described in References 1 and 2 below, with the advancement of micro-nanofabrication technology, X-ray multi-characteristic imaging (XMCI), which uses micro-nano gratings to simultaneously detect absorption, refraction, and small-angle scattering, has become a cutting-edge technology in international X-ray imaging research. It has important applications in medical imaging (e.g., breast cancer diagnosis as described in Reference 3, lung disease screening as described in Reference 4) and security inspection as described in Reference 5). Traditional X-ray imaging technology only utilizes the attenuation information of X-rays passing through an object, making it unable to detect low-density objects and presenting certain limitations. X-ray multi-characteristic imaging methods based on micro-nano gratings can simultaneously detect absorption due to attenuation, phase shift due to refraction, and dark field information generated by small-angle scattering. The phase and dark field information complement the absorption information, revealing the imaging characteristics of an object under different characteristics. This is why it is called X-ray multi-characteristic imaging. Currently, the most mainstream X-ray multi-characteristic imaging technology utilizes the Talbot-Lau effect (also known as the Talbot effect). As shown in Figure 1, its principle is to introduce three high-precision gratings G0, G1, and G2 on the basis of traditional X-ray imaging technology. Grating G0 is an absorption grating, and its function is to increase the spatial coherence of the light source. If the focus of the light source is small enough to meet the requirements of spatial coherence, grating G0 can be removed. Grating G1 is a phase grating that modulates the phase information of the X-rays to produce a light intensity equivalent to the period of grating G1. Stripes. Grating G2 is an absorption grating. Since the detector pixel is larger than the stripe period, the stripe changes cannot be directly interpreted by the detector. The G2 grating is needed to extract information from the stripes. Multiple images are collected through the micro-nano stepping of the G2 grating to obtain absorption, refraction, and small-angle scattering information. When X-ray light waves pass through an object, the object's absorption, small-angle scattering, and refraction of the X-rays will cause the wavefront to change, ultimately causing changes in the mean stripe intensity, contrast, and stripe position. By using the X-ray imaging information when no object is placed and subtracting it from the X-ray imaging information after the object is placed, the absorption, refraction, and small-angle scattering effects of the object on the X-rays are obtained. In X-ray multi-characteristic imaging, the grating plays the role of modulating the X-ray intensity and analyzing the fringe signal. The quality and consistency of the grating greatly affect the imaging quality of X-ray multi-characteristic imaging. Among them, the absorption grating (G0 grating, G2 grating) is the most difficult to produce. As shown in Figure 2, the grating has a periodic structure, h is its height, w is its width, p is its period, and the aspect ratio is 2h / p. As shown by the arrow in Figure 2, the light path is incident from directly above. The principle is to use the different absorption of X-rays by alternating strong absorption materials and weak absorption materials, and modulate the intensity of X-rays through the difference in X-ray absorption between these two parts. There are four important performance requirements for gratings: 1. Period p, which must be on the order of the X-ray wavelength, typically ranging from a few microns to several hundred microns. 2. Height h, and the metal element used for gold plating. Heavier metals, higher density, and higher atomic number tend to have a higher X-ray absorption coefficient. The higher the height h, the higher the X-ray absorption, and the height h requirement increases with increasing X-ray energy, typically ranging from 100μm to 300μm. 3. Grating area (w×p×f, where f is the number of layers of strong or weak absorbing material). The grating area determines the effective field of view of X-ray multi-characteristic imaging technology. A larger grating area results in a larger detector area, allowing for detection of larger objects, which is crucial in security inspections and medical imaging. 4. Sector structure. (See Figure 3.) Since X-ray source 900 is mostly a point source, the X-rays form a cone beam with a divergence angle. It is necessary to splice multiple gratings together to form a fan shape (arc shape) to meet the influence when the X-ray source 900 is a point light source, and the fan angle is the divergence angle of the point light source. As described in Reference 3, the grating period p used in breast cancer diagnosis is 4.2 μm, the gold-plated material of the absorption grating is gold, and the height h is 100 to 200 μm. Among them, the G2 grating area is greater than 195×19.2 mm 2, manufactured using a silicon-based process (described later). The grating used in lung disease screening has a period of only a few microns, while its height h exceeds 200 μm. Furthermore, since an effective field of view greater than 45 cm is required, the absorption grating G2 must be longer than 80 cm. It is manufactured using the LIGA process (electroforming, described later) by splicing multiple gratings together. Currently, the mainstream manufacturing processes for micro-nano absorption gratings include LIGA process and silicon-based process. LIGA (Lithgraphie, Galvanoformung, and Abformung), a technique pioneered by the Karlsruhe Institute of Technology (KIT) in Germany, is currently one of the leading technologies for fabricating X-ray gratings. It can consistently achieve an aspect ratio of 80:1 and has achieved a gold plating height of 280μm (aspect ratio of 116.7) on a grating period greater than 4.8μm. The LIGA process generally includes four key steps: X-ray exposure, development, electroforming, and injection molding. The key idea is to use X-ray lithography, followed by development, to form a periodic structure using photoresist. Electroplating is then used to create a template, and finally, after demolding, a high-aspect-ratio mold is formed. This mold is then plated with metal, and after demolding, injection molding is performed. The plated metal and the injection molding material have different absorption coefficients for X-rays, forming an absorption grating. Another silicon-based process, promoted by the Paul Scherrer Institute (PSI) in Switzerland, can also achieve an aspect ratio of 80:1 within a grating period of a few microns. This silicon-based process generally involves three steps: photolithography (including exposure and development), deep silicon etching, and gold plating. Again, using a silicon substrate as the base, a photoresist and hard mask are used to form periodic high-aspect-ratio structures within the silicon material. Metal plating is then applied, and the different X-ray absorption coefficients between the metal and the silicon substrate create an absorption grating. The mainstream production method is to use photolithography technology to form a periodic planar pattern (LIGA uses X-ray lithography, while silicon-based processes use visible light lithography), and then use additive (electroplating in LIGA) or subtractive technology (deep silicon etching in silicon-based processes) to expand this planar pattern into a high-aspect-ratio periodic structure with a certain height, and then use the gold plating process to plate heavy metal to form an absorption grating. These two solutions have many advantages, such as high grating period consistency, the ability to achieve precise low-period gratings, and are currently the mainstream choice for producing high aspect ratio gratings. However, these two solutions also have certain disadvantages, such as: 1. Both the LIGA process and the silicon-based process require the use of precise micro-nano processing equipment, which has a high technical threshold and very high production costs. 2. The gold plating time using LIGA process or silicon-based process is very long and it is currently difficult to achieve large-scale production. 3. The grating area is limited. For silicon-based processes, the effective area of ​​the grating is limited by the area of ​​the silicon wafer. Most silicon wafers are 4-inch, 6-inch, and 8-inch, and as the area increases, the production cost increases significantly. For the LIGA process, the grating area is determined by the template size and the size of the synchrotron radiation source. Similarly, it is difficult to produce large gratings. Therefore, in applications such as lung imaging, multiple gratings must be spliced ​​together, which introduces new difficulties. For example, the spacing between different gratings during splicing must be consistent with half a period. 4. For silicon-based processes, it is difficult to bend silicon wafers into fan-shaped gratings due to their brittle physical properties. For the LIGA process, however, due to its small area, mechanical fixtures are required to splice the gratings into fan-shaped gratings during the grating splicing process, which requires high machining precision (for example, the precision of the mechanical fixtures must be at the 0.1μm level), and the mechanical fixtures are prone to fatigue damage. Based on the above limitations, there is still room for improvement in gratings. References Reference 1: F. Pfeiffer et al., “Hard-X-ray dark-field imaging using a grating interferometer,” Nature Mater, vol. 7, no. 2, pp. 134-137, Feb. 2008, doi: 10.1038 / nmat2096. (F. Pfeiffer et al., “Hard-X-ray dark-field imaging based on grating interferometer effect,” Nature Mater, vol. 7, no. 2, pp. 134-137, Feb. 2008). Reference 2: Huang, Z.-F., Kang, K.-J., Zhang, L., Chen, Z.-Q., Ding, F., Wang, Z.-T., & Fang, Q.-G. (2009). Alternative method for differential phase-contrast imaging with weakly coherent hard x-rays. 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[2009] . Alternative approaches to weakly coherent hard X-ray differential phase contrast imaging. PHYSICAL REVIEW A, 79[1]). Reference 3: Rawlik, M., Pereira, A., Spindler, S., Wang, Z., Romano, L., Jefimovs, K., … Stampanoni, M. (2023). Increased dose efficiency of breast CT with grating interferometry. Optica, 10(7), 938-943. (Rovik M, Pereira A, Spindler S, Wang, Romano L, Jefimovs K … Stampanoni M,

[2023] Improving the dose efficiency of breast CT using grating interferometry. Optica, 10[7], 938-943). Reference 4: T. Partridge et al., “Enhanced detection of threat materials by dark-field x-ray imaging combined with deep neural networks,” Nat Commun, vol. 13, no. 1, p. 4651, Sep. 2022, doi: 10.1038 / s41467-022-32402-0. (Partridge et al., “Enhanced detection of threat materials by dark-field x-ray imaging combined with deep neural networks,” Nat Commun, vol. 13, no. 1, p. 4651, Sep. 2022, doi: 10.1038 / s41467-022-32402-0. Reference 5: M. Viermetz et al., “Dark-field computed tomography reaches the human scale,” Proc. Natl. Acad. Sci. USA, vol. 119, no. 8, p. e2118799119, Feb. 2022, doi: 10.1073 / pnas.2118799119. (M. Viermetz et al., “Dark-field computed tomography reaches the human scale,” Proc. Natl. Acad. Sci. USA, vol. 119, no. 8, p. e2118799119, Feb. 2022). Summary of the Invention In order to solve or alleviate at least one of the problems mentioned in the background art, the present application provides a method for manufacturing a high aspect ratio X-ray grating and a high aspect ratio X-ray grating. In the manufacturing method of the high aspect ratio X-ray grating provided in the present application, the grating includes m first material parts and n second material parts, -1≤mn≤1, and m and n are both positive integers. The manufacturing method includes alternatingly arranging the first material parts and the second material parts by stacking. In at least one embodiment, the lamination includes hot pressing lamination, and the hot pressing lamination includes: alternately placing the first material portion and the second material portion and compression molding the grating at a set temperature and a set pressure. In at least one embodiment, the manufacturing method includes: Providing the material of the first material portion and the material of the second material portion, wherein the material of the second material portion comprises a hot melt adhesive film; cutting the material of the first material portion and the material of the second material portion To form the first material portion and the second material portion with a set size and a set number, the first material portion and the second material portion are alternately placed and compression-molded into the grating at a set temperature and a set pressure; or A plurality of materials of the first material parts and a plurality of materials of the second material parts are provided, wherein the material of the second material parts comprises a hot melt adhesive film; the materials of the plurality of first material parts and the materials of the plurality of second material parts are alternately placed and compression-molded into a grating substrate at a set temperature; and the grating substrate is cut to form the grating having a set size. In at least one embodiment, the stack comprises a hot pressed stack comprising: A hot pressing mold is provided, the hot pressing mold comprising a first hot pressing mold portion and a second hot pressing mold portion capable of moving toward each other, the first hot pressing mold portion comprising a first contact surface, the second hot pressing mold portion comprising a second contact surface, the first contact surface and the second contact surface facing each other, and the first contact surface and the second contact surface being inclined in opposite directions relative to a height direction of the grating; The first material part and the second material part, or the material of the first material part and the material of the second material part, are alternately placed in the hot pressing mold. The first part of the hot pressing mold and the second part of the hot pressing mold move toward each other to extrude the grating or grating substrate. The grating with a set size can be obtained by cutting the grating substrate. In at least one embodiment, the stack comprises a fixed glue-coated stack comprising: providing a material for the second material portion and a plurality of the first material portions, wherein the material for the second material portion includes glue; A gluing mold is provided, the gluing mold comprising a first gluing mold portion and a second gluing mold portion disposed opposite to each other, the first gluing mold portion comprising a plurality of first tooth grooves at equal intervals, the second gluing mold portion comprising a plurality of second tooth grooves at equal intervals, wherein a spacing L1 between the first tooth grooves and a spacing L2 between the second tooth grooves satisfy the condition L1≤L2; inserting both ends of each first material portion into the first tooth groove and the second tooth groove respectively, and injecting the material of the second material portion between each first material portion; The material of the second material portion is solidified. In at least one embodiment, in the height direction of the grating, the first material portion includes a first material portion first area, a first material portion second area, and a first material portion third area. In the periodic direction of the grating, the second region of the first material portion contacts the first region of the first material portion and the third region of the first material portion. In at least one embodiment, at least one of thickness and material of the first area of ​​the first material portion, the second area of ​​the first material portion, and the third area of ​​the first material portion are different. In at least one embodiment, the stack-up comprises a powder spray stack-up comprising: Providing materials for the first material portion and the second material portion, wherein the materials for the first material portion include metal particles, a plasticizer, and a binder, and the materials for the second material portion include glue; The material of the first material portion and the material of the second material portion are sprayed alternately and solidified to obtain the grating or grating substrate. The grating with a set size can be obtained by cutting the grating substrate. The high aspect ratio X-ray grating provided in the present application includes m first material parts and n second material parts alternately stacked, -1≤mn≤1, and m and n are both positive integers, the grating includes a height direction and a periodic direction perpendicular to each other, in the plane formed by the height direction and the periodic direction, the height of the grating is h, the grating also includes a first edge and a second edge parallel to the periodic direction, the length of the first edge is D1, the length of the second edge is D2, and D1≤D2, h(m+n) / D1>200. In at least one embodiment, the grating is manufactured by the aforementioned method for manufacturing a high aspect ratio X-ray grating. BRIEF DESCRIPTION OF THE DRAWINGS FIG1 is a schematic diagram showing the principle of extracting multi-characteristic information using a phase-stepping data acquisition method in X-ray multi-characteristic imaging technology. FIG2 shows a schematic structural diagram of a grating known to the inventors. FIG3 shows a schematic diagram of a grating spliced ​​into a fan-shaped structure known to the inventor. FIG4 shows a schematic diagram of the structure of a high aspect ratio X-ray grating according to an embodiment of the present application. picture. FIG5 shows a front view of a high aspect ratio X-ray grating according to yet another embodiment of the present application. FIG6 is a schematic diagram showing a hot pressing lamination method in a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application. FIG7 is a schematic diagram showing an embodiment of cutting first and then hot pressing in a hot pressing and laminating manner in a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application. FIG8 is a schematic diagram showing an embodiment of hot pressing followed by cutting in a hot pressing and laminating manner in a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application. FIG9 is a schematic diagram showing hot pressing by a hot pressing mold in a hot pressing lamination method in a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application. FIG10 is a schematic diagram showing a method for manufacturing a high aspect ratio X-ray grating using a glue-coated mold in a fixed glue-coated lamination manner according to an embodiment of the present application. FIG11 is a schematic diagram showing a method for manufacturing a high aspect ratio X-ray grating using another glue-coating mold in a fixed glue-coating lamination manner according to an embodiment of the present application. FIG12 shows a schematic structural diagram of a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application, wherein the phase difference is modulated by utilizing the staggered arrangement of the first material portion in a fixed glue-coated lamination manner. 13 shows a schematic structural diagram of modulating the duty cycle by utilizing the staggered arrangement of the first material portion in a fixed glue-coated lamination method in a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application. FIG14 shows a schematic structural diagram of light intensity modulation using staggered arrangement of first material parts in a fixed glue-coated lamination method in a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application. FIG15 is a schematic diagram showing a powder spraying stack in a method for manufacturing a high aspect ratio X-ray grating according to an embodiment of the present application. DETAILED DESCRIPTION The following describes exemplary embodiments of the present application with reference to the accompanying drawings. The description is only used to teach those skilled in the art how to implement the present application, and is not intended to exhaust all possible ways of the present application, nor is it intended to limit the scope of the present application. The present application provides a method for manufacturing a high aspect ratio X-ray grating and a high aspect ratio X-ray grating. Referring to FIG4 , a high-aspect-ratio X-ray grating (hereinafter sometimes referred to as a "grating") provided in an embodiment of the present application includes m first material sections 100 and n second material sections 200 alternately stacked. Where mn is an integer, -1≤mn≤1. That is, the number of first material sections 100 and second material sections 200 can be equal or differ by 1, for example, m=n, m=n+1, or m=n-1. The first material portion 100 can be made of a material that strongly absorbs X-rays, such as metal foil. The second material portion 200 can be made of an organic film, such as polyethersulfone (PES) or ethylene acrylic acid copolymer (EAA). Various physical conditions (described later) can be used to tightly bond (e.g., adhere) the first and second material portions 100 and 200 together to form a stable grating. Furthermore, organic films can contain elements such as carbon, hydrogen, and oxygen, which have very low X-ray absorption, helping to form absorption gratings with high transmittance. Organic films also have good ductility, making it easier to process "sector-shaped" gratings (described later). The grating includes a height direction A and a periodic direction B that are perpendicular to each other. In the plane formed by the height direction A and the periodic direction B, the height of the grating is h. The grating also includes a first edge 300 and a second edge 400 parallel to the periodic direction B. The length of the first edge 300 is D1, the length of the second edge 400 is D2, and D1≤D2, h(m+n) / D1>200, that is, the aspect ratio of the grating is greater than 200. According to the inventors' understanding, in the pursuit of high aspect ratios, the current technological frontier is generally approaching an aspect ratio of 80:1, with a single example of 116.7:1. However, the present application is not limited by, for example, the wafer size in silicon-based processes or the size of the synchrotron radiation source in the LIGA process. By controlling the sizes of the first material portion 100 and the second material portion 200, an aspect ratio greater than 200:1 can be easily achieved. For example, the aspect ratio can be equal to 300, 400, 500, etc. In one embodiment of the present application, the aspect ratio is equal to 1000. It is understood that despite the above description and advantages, the solution of the present application can also be used to manufacture gratings with an aspect ratio less than 200. It can be understood that for the grating formed by alternately stacking the layers in this application, the height h of the grating depends on the The size of the material of the first material part 100 can easily achieve a height h of, for example, 1 mm to 2 cm, without requiring precise micro-nano processing equipment such as photolithography equipment. It is understood that as the number of stacked layers increases, the length in the periodic direction, for example, the length (D1) of the first edge 300, increases accordingly. This allows for a larger grating area (w × D1), unlike LIGA or silicon-based processes, which are limited by the periodic length. This application allows for the direct manufacture of gratings that are longer in the periodic direction B and larger in area, without the need to increase the area by splicing multiple existing gratings. It can be understood that in the grating of the embodiment shown in FIG4 , D1 = D2. In the grating of the embodiment shown in FIG5 , D1 < D2. In this case, the grating is formed into a "sector" (or trapezoidal) shape, which can better cope with X-rays formed into a cone beam. It does not require multiple gratings such as those shown in FIG4 to be spliced ​​into a sector shape, which can save the complicated installation and debugging work when splicing gratings. The method for manufacturing a high aspect ratio X-ray grating provided in the present application includes alternately arranging first material parts 100 and second material parts 200 by stacking. More specifically, the stacking method may include hot pressing stacking, fixed glue coating stacking, and powder spraying stacking. Referring to Figure 6 , the first material portion 100 can be made of metal foil, and the second material portion 200 can be made of hot-melt adhesive film. Hot-melt adhesive film is very soft at room temperature, but becomes sticky at high temperatures. At room temperature, the metal foil and hot-melt adhesive films can be alternately stacked and then bonded together using the physical conditions of high temperature and high pressure (referred to herein as "hot pressing") to form a grating. This lamination method is therefore referred to as hot-press lamination. It should be understood that the thicker arrows in Figure 6 represent applied pressure. The thickness of the metal foil can be 5 to 2000 μm, the thickness of the hot melt adhesive film can also be 5 to 2000 μm, and the period p of the grating (the sum of the thickness of a first material part 100 and a second material part 200) can be as low as 10 μm. In one embodiment of the present application, the hot pressing lamination method can be cutting first and then hot pressing, or hot pressing first and then cutting. 7 , the method of cutting first and then hot pressing may include: providing the material of the first material part 100 and the material of the second material part 200; cutting the material of the first material part 100 and the material of the second material part 200 to form the first material part 100 and the second material part 200 of a set size and a set number; The first material portion 100 and the second material portion 200 are alternately placed and compressed at a set temperature and set pressure to form a grating. It can be understood that in Figure 7, from right to left, the materials are cut and stacked in sequence. After stacking, they are hot-pressed as shown in Figure 6. Referring to Figure 8 , the hot pressing followed by cutting method can include: providing a plurality of first material sections 100 and a plurality of second material sections 200; alternately placing the plurality of first material sections 100 and the plurality of second material sections 200 and compressing and molding them at a set temperature into a grating substrate 600; and cutting the grating substrate 600 to form a grating of set dimensions. It can be understood that in Figure 8 , from right to left, the materials are first stacked and compressed, and then cut to form a grating of set dimensions. For example, the grating period p (the thickness of the first material section 100 and the second material section 200) can be 40 μm, the height h can be 1 cm, and the aspect ratio can be 500:1. It is understood that for ease of illustration, the dimensions and proportions in some of the drawings, including Figures 7 and 8, may differ from the description or the dimensions and proportions of the actual product. In the event of such a difference, the written description in the specification shall prevail. Furthermore, referring to FIG9 , since the hot melt adhesive film has good ductility, the structure of the grating can be adjusted through the mold. That is, the hot pressing lamination method also includes: providing a hot pressing mold 500, the hot pressing mold 500 includes a first hot pressing mold part 510 and a second hot pressing mold part 520 that can move toward each other, the first hot pressing mold part 510 includes a first contact surface 511, the second hot pressing mold part 520 includes a second contact surface 521, the first contact surface 511 and the second contact surface 521 are opposite to each other, and the first contact surface 511 and the second contact surface 521 are inclined in opposite directions relative to the height direction A of the grating, that is, the up and down direction in Figure 9; each first material part 100 and the second material part 200 are alternately placed in the hot pressing mold 500, the first hot pressing mold part 510 and the second hot pressing mold part 520 move toward each other to extrude the grating, so that the first edge 300 of the grating is shorter than the second edge 400, that is, D1<D2, so as to achieve a grating with a "fan-shaped" (or trapezoidal) shape as shown in Figure 5, which can better cope with X-rays formed into a cone beam. It can be understood that the thicker arrows in FIG9 represent applied pressure. In one embodiment of the present application, referring to FIG10 and FIG11, a method for fixing the glued laminate may include: providing a material of a second material portion 200 and a plurality of first material portions 100, wherein the material of the second material portion 200 includes glue; providing a glue coating mold 700, wherein the glue coating mold 700 includes a glue coating mold arranged opposite to the glue coating mold. The first part 710 and the second part 720 of the glue coating mold, the first part 710 of the glue coating mold includes a plurality of first tooth grooves 711 with equal spacing, and the second part 720 of the glue coating mold includes a plurality of second tooth grooves 721 with equal spacing, and the spacing L1 between the first tooth grooves 711 and the spacing L2 between the second tooth grooves 721 satisfy L1≤L2; the two ends of each first material part 100 are respectively inserted into the first tooth groove 711 and the second tooth groove 721, and glue is injected between each first material part 100 and waited for solidification. Finally, the glue coating mold 700 can be removed to obtain a complete grating. For example, the glue can be ultraviolet curing glue (UV glue), which can be cured by ultraviolet light irradiation after the ultraviolet curing glue is injected. As can be understood, referring to Figure 10 , when L1 = L2, D1 = D2. Referring to Figure 11 , when L1 < L2, D1 < D2, the first material portion 100 will naturally tilt, forming a "fan-shaped" (or trapezoidal) shape as shown in Figure 5 , which better responds to cone-beam X-rays. In other words, different gratings can be produced by varying the tooth-slot arrangement. Furthermore, referring to Figures 12, 13, and 14, in the height direction A of the grating, the first material portion 100 may include a first region 110, a second region 120, and a third region 130. In the periodic direction B, the second region 120 may contact the first region 110 and the third region 130. Furthermore, at least one of the thickness and material of the first region 110, the second region 120, and the third region 130 may differ. By adjusting the thickness, material, and position of the first region 110, the second region 120, and the third region 130, various gratings capable of modulating X-rays as needed can be manufactured. For example, referring to FIG12 , the first material portion first zone 110, the first material portion second zone 120, and the first material portion third zone 130 can be made to have the same thickness and be made of the same material. In the periodic direction B, the position of the first material portion second zone 120 is offset relative to the position of the first material portion first zone 110 and the position of the first material portion third zone 130 by the thickness of the first material portion second zone 120, resulting in a phase difference of π between the first material portion second zone 120 and the first material portion first zone 110 (and the first material portion third zone 130). Of course, by adjusting the degree of positional offset, a variety of phase differences can be modulated, which will not be detailed in this application. The duty ratio of different regions in the grating height direction can be adjusted by adjusting the thickness of the first material portion first region 110, the first material portion second region 120 and the first material portion third region 130. For example, referring to FIG. 13 , the first material portion first region 110, the first material portion second region 120 and the first material portion third region 130 are The material of the first material portion 130 is the same, and the thickness of the second area 120 of the first material portion is less than the thickness of the first area 110 of the first material portion and the third area 130 of the first material portion. The duty cycle of the first area 810 where the first area 110 of the first material portion is located is 0.7, and the duty cycle of the second area 820 where the second area 120 of the first material portion is located is 0.3. Of course, by controlling the thickness, more types of duty cycles can be modulated, and this application will not go into details one by one. In the plane formed by the height direction A and the periodic direction B, the duty cycle is: the area of ​​the second material portion 200 / (the area of ​​the first material portion 100 + the area of ​​the second material portion 200). The intensity of the X-ray phase can be adjusted by adjusting the materials of the first material portion, first zone 110, second zone 120, and third zone 130. For example, referring to FIG14 , the materials of the first material portion, first zone 110, and third zone 130 are the same, while the material of the second zone 120 is different from that of the other two zones, to adjust the intensity of the X-ray phase. Of course, the first material portion 100 can be set to have more areas, or fewer areas (such as two areas) to achieve more types of adjustments. It can be understood that the left and right sides of the grating in Figures 12, 13, and 14 have unremoved glue coating molds 700, and the glue coating mold 700 and the material of the first material portion 100 in the tooth grooves (first tooth grooves 711, second tooth grooves 721) of the glue coating mold 700 can be removed in a subsequent stage to form the grating provided in the embodiment of the present application. It can be understood that in these figures, the left and right direction is the height direction A, and the up and down direction is the periodic direction B. X-rays can be emitted from the height direction A, for example, from left to right, toward the grating. In one embodiment of the present application, referring to FIG15 , the powder spray coating stack includes: providing a material of a first material portion 100 and a material of a second material portion 200, wherein the material of the first material portion 100 includes metal particles, a plasticizer and a binder, and the material of the second material portion 200 includes glue; alternately spraying the material of the first material portion 100 and the material of the second material portion 200, and solidifying to obtain a grating substrate 600; and as shown in FIG8 , cutting the grating substrate 600 to obtain a grating of a set size. It will be appreciated that the material of the first material portion 100 can be formed into a fluid colloid under high temperature conditions and then sprayed using a sprayer. Similarly, the material of the second material portion 200 can be sprayed using another sprayer. A powder spraying mold (not shown) can be provided to serve as a solidification location for the sprayed material. In Figure 15, the two thicker arrows represent spraying. Furthermore, by controlling the spraying pressure and the spraying time, the first edge 300 of the grating is The second edge 400 satisfies D1<D2, forming a grating with a "fan-shaped" (or trapezoidal) shape as shown in FIG5 , which can better cope with X-rays formed into a cone beam. LIGA and silicon-based processes can produce precise low-period gratings, but are more difficult to produce with high aspect ratios and fan-shaped gratings. The method provided in this application can mass-produce high-period, large-area, high-aspect-ratio gratings, including those with the fan-shaped structure shown in Figure 5. This method does not require sophisticated micro-nanofabrication equipment, resulting in low processing costs and suitable for large-scale mass production. It can be understood that the grating provided in the present application can be an absorption grating, that is, the G0 grating and / or G2 grating in the X-ray multi-characteristic imaging technology described in the background technology. The above is a preferred embodiment of the present application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as within the scope of protection of the present application. Description of Reference Numerals 100 First Materials Department 110 First Materials Department, First District 120 First Materials Department, Second Area 130 First Materials Department, Third District 200 Second Materials Department 300 First Edge 400 Second Edge 500 hot pressing mold 510 Hot Pressing Mold Section 1 511 First Contact Surface 520 Hot Pressing Mold Section 2 521 Second Surface of Resistance 600 grating substrate 700 Glue Coating Mold 710 Gluing Mold Part 1 711 First tooth groove 720 Glue Coating Mold Part 2 721 Second tooth groove 810 First Area 820 Second Area 900 X-ray source

Claims

1. A method for manufacturing a high aspect ratio X-ray grating, wherein the grating comprises m first material portions (100) and n second material portions (200), wherein -1≤mn≤1, and m and n are both positive integers, wherein: The manufacturing method comprises alternately arranging the first material portion (100) and the second material portion (200) in a stacking manner.

2. The method for manufacturing a high aspect ratio X-ray grating according to claim 1, wherein: The lamination includes hot pressing lamination, and the hot pressing lamination includes: placing the first material portion (100) and the second material portion (200) alternately and compressing and molding the grating at a set temperature and a set pressure.

3. The method for manufacturing a high aspect ratio X-ray grating according to claim 1, wherein: The manufacturing method comprises: Providing the material of the first material portion (100) and the material of the second material portion (200), wherein the material of the second material portion (200) comprises a hot melt adhesive film; cutting the material of the first material portion (100) and the material of the second material portion (200) to form the first material portion (100) and the second material portion (200) having a set size and a set number, and alternately placing the first material portion (100) and the second material portion (200) and compressing and molding the grating at a set temperature and a set pressure; or A plurality of materials of the first material parts (100) and a plurality of materials of the second material parts (200) are provided, wherein the material of the second material parts (200) comprises a hot melt adhesive film; the materials of the plurality of first material parts (100) and the materials of the plurality of second material parts (200) are alternately placed and compression-molded into a grating substrate (600) at a set temperature; and the grating substrate (600) is cut to form the grating having a set size.

4. The method for manufacturing a high aspect ratio X-ray grating according to claim 1, wherein: The lamination includes a hot press lamination, and the hot press lamination includes: A hot pressing mold (500) is provided, wherein the hot pressing mold (500) includes a first hot pressing mold part (510) and a second hot pressing mold part (520) capable of moving toward each other, the first hot pressing mold part (510) includes a first contact surface (511), the second hot pressing mold part (520) includes a second contact surface (521), the first contact surface (511) and the second contact surface (521) face opposite to each other, and ... The interference surface (511) and the second interference surface (521) are inclined in opposite directions relative to the height direction (A) of the grating; The first material portion (100) and the second material portion (200), or the material of the first material portion (100) and the material of the second material portion (200), are alternately placed in the hot pressing mold (500), and the first portion (510) and the second portion (520) of the hot pressing mold are moved toward each other to extrude and form the grating or grating substrate (600), and the grating having a set size can be obtained by cutting the grating substrate (600).

5. The method for manufacturing a high aspect ratio X-ray grating according to claim 1, wherein: The stack includes a fixed glue-coated stack, and the fixed glue-coated stack includes: Providing a material for the second material portion (200) and a plurality of the first material portions (100), wherein the material for the second material portion (200) includes glue; A gluing mold (700) is provided, wherein the gluing mold (700) comprises a first gluing mold portion (710) and a second gluing mold portion (720) disposed opposite to each other, wherein the first gluing mold portion (710) comprises a plurality of first tooth grooves (711) with equal spacing, and the second gluing mold portion (720) comprises a plurality of second tooth grooves (721) with equal spacing, wherein a spacing L1 between the first tooth grooves (711) and a spacing L2 between the second tooth grooves (721) satisfy the condition L1≤L2. Inserting the two ends of each first material portion (100) into the first tooth groove (711) and the second tooth groove (721) respectively, and injecting the material of the second material portion (200) between each first material portion (100); The material of the second material portion (200) is solidified.

6. The method for manufacturing a high aspect ratio X-ray grating according to claim 5, wherein: In the height direction (A) of the grating, the first material portion (100) includes a first material portion first area (110), a first material portion second area (120) and a first material portion third area (130), In the periodic direction (B) of the grating, the second region (120) of the first material portion contacts the first region (110) of the first material portion and the third region (130) of the first material portion.

7. The method for manufacturing a high aspect ratio X-ray grating according to claim 6, wherein: At least one of thickness and material of the first area (110) of the first material portion, the second area (120) of the first material portion, and the third area (130) of the first material portion is different.

8. The method for manufacturing a high aspect ratio X-ray grating according to claim 1, wherein: The stack comprises a powder sprayed coating stack comprising: Providing materials for the first material part (100) and the second material part (200), wherein the materials for the first material part (100) include metal particles, a plasticizer, and a binder, and the materials for the second material part (200) include glue; The material of the first material part (100) and the material of the second material part (200) are sprayed alternately and solidified to obtain the grating or grating substrate (600). The grating having a set size can be obtained by cutting the grating substrate (600).

9. A high aspect ratio X-ray grating, wherein: The grating includes m first material portions (100) and n second material portions (200) alternately stacked, wherein -1≤mn≤1, and m and n are both positive integers. The grating includes a height direction (A) and a periodic direction (B) perpendicular to each other. In a plane formed by the height direction (A) and the periodic direction (B), the height of the grating is h. The grating also includes a first edge (300) and a second edge (400) parallel to the periodic direction (B). The length of the first edge (300) is D1, the length of the second edge (400) is D2, D1≤D2, and h(m+n) / D1>200.

10. The high aspect ratio X-ray grating according to claim 9, characterized in that: The grating is manufactured by the method for manufacturing a high aspect ratio X-ray grating according to any one of claims 1 to 8.

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