A method for manufacturing a lens for x-rays and a lens

Abstract

The present application relates to optical components, in particular to a manufacturing method of a lens for X-ray, and a lens, comprising the following steps: selecting a middle layer substrate material, preparing the substrate material into a substrate; carrying out film plating, selecting different materials to plating layer by layer in turn to form symmetrical film layers of different materials layer by layer on both sides of the substrate; forming a block after completing the film plating, drilling along the parallel direction of the film plating layer or the parallel surface of the substrate to form a curved surface on one side of the block, forming a curved surface block; polishing the curved surface of the curved surface block to form a lens. The present application realizes X-ray refraction focusing, forms a composite material lens by introducing different refractive index materials, and realizes X-ray aplanatic focusing through a circular cross section while reducing the processing difficulty.

Description

Technical Field

[0001] The present invention relates to optical components, in particular to a method for manufacturing a lens for X-rays, and also to a lens. Background Art

[0002] The deep penetration depth of X-rays in matter allows for the investigation of the internal structure of objects without destroying the sample or in specialized sample environments, such as chemical reactors or pressure cells. This makes them ideal for studying physical and chemical processes in situ and in real time. In recent years, the spectral brightness of advanced X-ray sources, represented by synchrotron radiation diffraction-limited light sources and X-ray free-electron lasers (XFELs), has significantly increased, along with improvements in their coherence and repetition rates. These sources are increasingly being used in X-ray analysis, including X-ray microscopy and X-ray computed tomography (CT), X-ray micro- and nano-interferometry, and X-ray absorption spectroscopy. However, the design and operation of beamlines at these advanced light sources, the maintenance and transmission of their superior performance, and the implementation of microanalytical experiments rely on the availability of near-perfect X-ray optical components. X-ray refractive lenses, used to collimate or focus the incident beam, play a crucial role. However, the low refractive index of materials in the X-ray band and the short wavelengths' sensitivity to material defects and surface roughness present challenges in the design and fabrication of X-ray lenses, hindering the full utilization of the exceptional performance of these advanced light sources. Therefore, the present invention intends to design a new type of X-ray lens to obtain sufficiently high resolution, reduce processing difficulty, and realize efficient focusing of coherent X-rays.

[0003] According to the optical path theory, there are two main approaches to achieve X-ray focusing by refraction: (1) controlling the material thickness; (2) controlling the material refractive index. A refractive lens is an optical device that controls the optical path by changing the material thickness at different positions perpendicular to the beam, such as Figure 1 However, in order to achieve X-ray focusing without spherical aberration, the cross-section needs to be designed as an aspherical surface, which places high demands on lens processing and makes its manufacturing more difficult. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for manufacturing a lens for X-rays and a lens, which can achieve better focusing of X-rays and reduce the difficulty of processing by comprehensively controlling the surface shape and refractive index.

[0005] A first aspect of the present invention provides a method for manufacturing a lens for X-rays, comprising the following steps:

[0006] Selecting an intermediate layer base material and preparing the base material into a substrate;

[0007] Performing film coating, selecting different materials to coat layer by layer in sequence, so as to form symmetrical film layers of different materials on both sides of the substrate;

[0008] After the coating is completed, a block is formed, and holes are drilled in a direction parallel to the coating layer or the parallel surface of the substrate to form a curved surface on one side of the block, thereby forming a curved surface block;

[0009] The curved surface of the curved block is ground and polished to form a lens.

[0010] The lens manufacturing method of the present invention utilizes thin film deposition to form multiple layers of thin films of different materials on a substrate, thereby forming a block. Holes are drilled into the block to form a curved surface, which is then polished to produce a gradient index refractive lens. In the present invention, the intermediate layer substrate can be made of materials with excellent optical properties and chemical stability, such as glass, quartz, sapphire, and diamond. The selected material can be prepared into a substrate through cutting and polishing.

[0011] While achieving X-ray refraction and focusing, the present invention forms a composite material lens by introducing materials with different refractive indices. By adopting this method, X-ray focusing without spherical aberration is achieved through a circular cross-section, while reducing the difficulty of processing.

[0012] In some feasible embodiments, a coordinate system is established through the central tangent point of the arc surface, with the z-axis being along the propagation direction of the light beam and the y-axis being perpendicular to the propagation direction of the light beam;

[0013] Assume that the X-ray lens made of a single material has an elliptical surface required to focus horizontally incident X-rays, and let the semi-major axis of the ellipse be a, the semi-minor axis be b, and one end point of the major axis of the ellipse be the origin of the coordinate system;

[0014] Assume that the focusing surface of the lens manufactured by the X-ray lens manufacturing method is an arc surface, and the radius of the arc surface is R;

[0015] The surface shapes of the original elliptical surface and the processed arc surface meet the following conditions:

[0016]

[0017] Any horizontal line with coordinate y intersects the ellipse and circle at points P(z1, y) and Q(z2, y) respectively, then

[0018]

[0019] Assuming that the refractive index n(y) of the material changes along the y-axis, and assuming that the refractive index is n0 when y=0, then

[0020] n(y)z2=n0z1+(z2-z1) (3)

[0021] In some feasible embodiments, during the coating process, the thickness of each coating layer is controlled to be 30 to 60 microns, or 80 microns, or 100 microns.

[0022] In some feasible embodiments, during coating, the coating layer material is any one of Au, Ag, Pt, Cu, Ni, Fe, Al, Si, Co, V, Ti, diamond, Be, SiC, and PMMA.

[0023] In some feasible embodiments, during coating, starting from the substrate along the coating direction, the coating layers are arranged in order from small to large according to the refractive index of the X-ray of corresponding energy.

[0024] In some feasible embodiments, starting from the substrate along the coating direction, the film layer materials are as follows:

[0025] Au, Ag, Pt, Cu, Fe, Al, Si, diamond, Be, SiC, PMMA, where the substrate material is Au; or Cu, Ni, Co, Fe, Zn, V, Ti, where the substrate material is Cu.

[0026] This allows for control of lens properties such as transmittance and aberrations. For X-rays, controlling the coating thickness according to the aforementioned parameters can further alter the lens's focusing effect and reduce processing complexity. This solution utilizes coatings of varying materials, thicknesses, and arrangements to optimize the lens' optical and physical properties, improving both performance and applicability.

[0027] In some feasible embodiments, during grinding and polishing, blowing is performed along the axial direction of the arc surface.

[0028] The second aspect of the present invention further provides a lens, which is prepared by a method for manufacturing a lens for X-rays according to the first aspect and its improved solution.

[0029] In some feasible embodiments, the parallelism of the lens coating and the substrate is less than 0.01 degrees, and the flatness is less than 5 nanometers.

[0030] In some feasible embodiments, in the lens, the deviation between the arc line of the cross section of the arc surface along the coating direction and the ideal circular arc line does not exceed 1%; and the surface roughness of the arc surface is less than 2 microns.

[0031] In some feasible embodiments, the lens is a lens for focusing X-rays. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0033] Figure 1 A schematic cross-sectional view of a current X-ray refractive index lens is provided;

[0034] Figure 2 A schematic diagram illustrating a gradient refractive index composite material lens according to an embodiment of the present invention;

[0035] Figure 3 A schematic diagram illustrating the principle of manufacturing a gradient refractive index refractive lens profile in an embodiment;

[0036] Figure 4 is a schematic diagram for illustrating a lens in Example 2;

[0037] Figure 5 is a schematic diagram of an example of a gradient refractive index lens in an embodiment;

[0038] Reference numerals and corresponding component names:

[0039] 1-substrate, 2-lens coating. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0041] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not necessarily required to practice the present invention. In other instances, well-known structures, circuits, materials, or methods are not described in detail to avoid obscuring the present invention.

[0042] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combinations and / or subcombinations. Furthermore, it will be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes only and are not necessarily drawn to scale. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] In the description of the present invention, it should be understood that the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] Reference Figures 1 to 4 , a method for manufacturing a lens for X-rays, comprising the following steps:

[0046] An intermediate layer base material is selected and the base material is prepared as a substrate 1. The substrate needs to be cleaned and processed to ensure the smoothness and cleanliness of the surface, which can be done by mechanical or chemical methods.

[0047] The substrate material can be made of gold (Au), copper (Cu), glass, quartz, silicon, etc. The substrate size can be processed by cutting and grinding. Cutting can be done with a cutting machine or saw blade, while grinding requires the use of abrasives and grinding wheels. The grinding process requires gradually reducing the size of the particles and the degree of wear of the grinding wheel to achieve the required surface smoothness and flatness. Cleaning can be performed here, and cleaning can be done with solvents, ultrasonic waves, etc. After completion, inspection can be carried out with equipment such as microscopes and scanning electron microscopes. Testing can be done with equipment such as spectrometers and surface profilers to measure the physical and optical properties of the substrate.

[0048] Film coating is performed. Different materials are selected and applied layer by layer to form symmetrical layers of different materials on both sides of substrate 1. Specifically, after cleaning and inspecting substrate 1, substrate 1 is placed in a chamber and the air and other gases are evacuated. A combination of mechanical and molecular pumps can be used to achieve a high vacuum. Thin film deposition is then performed. Thin films can be deposited on substrate 1 using methods such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and electroplating. The specific method and parameters should be selected and optimized based on the materials used and the coating requirements. PVD utilizes the physical action of high-energy particles to deposit thin films in a vacuum environment. CVD uses a chemical reaction to deposit solid thin films on substrate surfaces. CVD includes thermal CVD and PECVD. Electroplating deposits metallic or non-metallic thin films on substrate surfaces through electrochemical reactions. During thin film deposition, parameters such as temperature, vacuum, and gas pressure are controlled to ensure film quality and performance. Furthermore, parameters such as deposition rate and film thickness must be controlled to meet the design requirements of this solution.

[0049] After the coating is completed, a block is formed, and a hole is drilled in a direction parallel to the coating layer or the parallel surface of the substrate 1 to form a curved surface on one side of the block to form a curved surface block; the curved surface of the curved surface block is ground and polished to form a lens.

[0050] The lens manufacturing method of the present invention utilizes thin film coating to form multiple thin film layers of different materials on a substrate 1, thereby forming a block. Holes are drilled into the block to form a curved surface, which is then polished to produce the lens. In the present invention, the intermediate layer base material can be selected from materials with excellent optical properties and chemical stability, such as glass, quartz, sapphire, and diamond. The selected material can be prepared into the substrate 1 through cutting, polishing, and other methods.

[0051] Assume that the final surface shape is a relatively easy-to-machine circular surface, while the actual optical path is an elliptical surface that can achieve ideal focusing, where the circle and the ellipse are tangent at a point. Establish a coordinate system through the center tangent point of the arc surface, with the z-axis along the direction of light beam propagation and the y-axis perpendicular to the direction of light beam propagation; let the semi-major axis of the ellipse be a, the semi-minor axis be b, and one end point of the major axis of the ellipse be the origin of the coordinate system; let the radius of the arc surface be R; the surface shape of the machined arc surface meets the following conditions:

[0052]

[0053] Any horizontal line with coordinate y intersects the ellipse and circle at points P(z1, y) and Q(z2, y) respectively, then

[0054]

[0055] Assuming that the refractive index n(y) of the material changes along the y-axis, and assuming that the refractive index is n0 when y=0, then

[0056] n(y)z2=n0z1+(z2-z1) (3)

[0057] Combining equations (2) and (3), we can obtain the relationship between the refractive index n and y.

[0058] During the coating process, the thickness of the coating layer is controlled to be 30 to 60 microns or 80 microns or 100 microns. During the coating process, the coating layer material is any one of silicon (Si), diamond, PMMA, beryllium (Be), sapphire, SiC, gold (Au), platinum (Pt), copper (Cu), iron (Fe), aluminum (Al), silver (Ag), zinc, vanadium, titanium, etc. During the coating process, starting from the substrate 1 along the coating direction, the coating layer can be selected in sequence as gold (Au), silver (Ag), platinum (Pt), copper (Cu), iron (Fe), aluminum (Al), silicon (Si), diamond, beryllium (Be), SiC, PMMA, etc., and needs to be selected according to the refractive index of the X-ray of the corresponding energy. While achieving X-ray refraction and focusing, this embodiment reduces the difficulty of lens processing and improves focusing efficiency by introducing a composite refractive index material.

[0059] like Figure 5 As shown in the figure, for example, for 8keV X-rays, a Cu substrate is used, and Ni, Co, Fe, Zn, V, and Ti thin films are deposited in sequence. The Cu substrate is located in the middle, with a total thickness of 200 microns. The Ni, Co, Fe, and Zn films are 100 microns thick, and the V and Ti films are 50 microns thick, with a symmetrical top-to-bottom surface. The resulting lens has a circular radius of 5 mm.

[0060] The detailed parameters are shown in the table below, and the obtained refractive index satisfies formula (3):

[0061]

[0062]

[0063] For X-rays with other photon energies, optional materials include gold (Au), silver (Ag), platinum (Pt), copper (Cu), iron (Fe), aluminum (Al), silicon (Si), diamond, beryllium (Be), SiC, PMMA, etc., but are not limited to these materials. Detailed design is required based on actual conditions.

[0064] In this scheme, the coating layers are arranged in ascending order based on their refractive index for the corresponding X-ray energies. For example, for the aforementioned 8keV X-rays, the order of coating, starting from the substrate and moving toward both sides, can be platinum (Pt), gold (Au), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), zinc (Zn), vanadium (V), titanium (Ti), diamond (C), aluminum (Al), silicon (Si), beryllium (Be), and so on. When arranging these layers, if one material serves as the substrate, the adjacent material is selected from the next material in the order, and so on.

[0065] For example, the materials of the layers starting from the substrate to both sides can be: Pt, Au, Ag, Cu, Fe, Al, Si, diamond, Be, SiC, PMMA, where the substrate material is Pt; or, Cu, Ni, Co, Fe, Zn, V, Ti, where the substrate material is Cu; or, Au, Ag, Cu, Fe, Al, Si, where the substrate is Au.

[0066] The drilling tool may be a drill or a laser cutter, as long as it can reliably ensure that the above formula can obtain the surface shape.

[0067] During grinding and polishing, the spraying is performed along the axial direction of the arc surface, and the spraying nozzle can be a high-pressure gas nozzle.

[0068] Example 2

[0069] Combine Figure 4 A lens is prepared by the method for manufacturing a lens for X-rays according to the above-mentioned embodiment 1. The parallelism of the lens coating 2 and the substrate 1 is less than 0.01 degrees, and the flatness is less than 5 nanometers. In the lens, the deviation of the arc of the cross section along the coating direction from the ideal circular arc does not exceed 1%; the surface roughness of the arc is less than 2 microns. The lens is a lens for focusing X-rays, and the lens can be used in X-ray imaging, X-ray fluorescence spectrometers, X-ray diffractometers, X-ray interferometers and other X-ray related fields.

[0070] High-precision parallelism and flatness. High parallelism and flatness ensure the stability of the X-ray propagation direction and position within the lens, enabling high-quality results in X-ray applications such as imaging, fluorescence spectrometry, diffractometers, and interferometers. Furthermore, high parallelism and flatness accuracy effectively reduce X-ray imaging distortion caused by lens deformation.

[0071] This lens is used in X-ray lenses with high precision of the curved surface. The curved surface is a key component for focusing X-rays. The deviation of the arc of the cross section along the coating direction from the ideal circular arc does not exceed 1%, which can ensure the focusing effect of X-rays in the lens, thereby improving the imaging quality of X-rays.

[0072] To achieve the aforementioned requirements of less than 0.01 degrees of parallelism and less than 5 nanometers of flatness between the lens coating 2 and the substrate 1, high-precision substrate 1 materials with high flatness and stability can be selected, such as quartz, silicon, or magnesium-aluminum (Al) plates. In addition to polishing and thin-film deposition, precise measurement of the parallelism and flatness of the substrate 1 can be achieved through precision grinding and other processes, combined with high-precision measuring tools and equipment such as high-precision platforms and three-dimensional coordinate measuring machines. Processed lenses can also undergo quality control and adjustment; if significant deviations in parallelism or flatness are observed, fine-tuning or reprocessing can be performed.

[0073] Furthermore, the curved surface has a roughness of less than 2 microns, which reduces X-ray scattering and reflection caused by lens surface roughness, thereby improving lens transmittance and imaging quality. To achieve this surface roughness requirement of less than 2 microns, in addition to selecting materials according to the requirements of this embodiment, techniques such as electrolytic polishing and electron beam machining can also be used to remove, calender, and smooth the surface.

[0074] Wide range of applications. The X-ray lens in this solution is suitable for X-ray imaging, X-ray fluorescence spectrometers, X-ray diffractometers, X-ray interferometers, and other X-ray-related fields, and has broad application prospects and market potential. This X-ray lens not only improves X-ray imaging quality but also provides more accurate and reliable data for X-ray research. The X-ray lens in this solution features high-precision parallelism and flatness, high-precision curved surfaces, and a wide range of applications.

[0075] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a lens for X-rays, characterized in that: The following steps are involved: Select an intermediate layer base material and prepare the base material into a substrate; establish a coordinate system through the central tangent point of the arc surface, with the z-axis along the beam propagation direction and the y-axis perpendicular to the beam propagation direction; assume that the surface shape required for focusing horizontally incident X-rays on an X-ray lens made of a single material is an elliptical surface, with the semi-major axis of the ellipse being a, the semi-minor axis being b, and one end point of the major axis of the ellipse being the origin of the coordinate system; assume that the focusing surface shape of the lens manufactured by the X-ray lens manufacturing method is a circular arc surface, with the radius of the arc surface being R; the surface shapes of the original elliptical surface and the processed circular arc surface satisfy the following conditions: （1）； Any horizontal line with coordinate y intersects the ellipse and circle at points P(z1, y) and Q(z2, y) respectively, then （2）； If the refractive index n(y) of the material varies along the y-axis, and the refractive index is n0 when y=0, then (3); Performing film coating, wherein different materials are selected and coated layer by layer in sequence to form symmetrical film layers of different materials on both sides of the substrate; wherein, during film coating, the coating layer material is any one of Au, Ag, Pt, Cu, Ni, Fe, Al, Si, Co, V, Ti, diamond, Be, SiC, and PMMA; during film coating, starting from the substrate and along the coating direction, the coating layers are arranged in ascending order according to the refractive index of the X-ray of corresponding energy; After the coating is completed, a block is formed, and a hole is drilled in a direction parallel to the coating layer or the parallel surface of the substrate to form a curved surface on one side of the block to form a curved surface block; the curved surface of the curved surface block is ground and polished to form a lens.

2. The method for manufacturing an X-ray lens according to claim 1, wherein: During the coating process, the coating layer thickness is controlled within a range of 30 to 60 microns, or the coating layer thickness is controlled within a range of 80 microns, or the coating layer thickness is controlled within a range of 100 microns.

3. The method for manufacturing an X-ray lens according to claim 1, wherein: During grinding and polishing, the spraying is performed along the axial direction of the arc surface.

4. The method for manufacturing an X-ray lens according to claim 1, wherein: Starting from the substrate along the coating direction, the coating layer materials are: Pt, Au, Ag, Cu, Fe, Al, Si, diamond, Be, SiC, PMMA, where the substrate material is Pt; or, Cu, Ni, Co, Fe, Zn, V, Ti, where the substrate material is Cu; or, Au, Ag, Cu, Fe, Al, Si, where the substrate is Au.

5. A lens, characterized in that: The lens is prepared by the method for manufacturing a lens for X-rays according to any one of claims 1 to 4.

6. The lens according to claim 5, characterized in that: The parallelism of the lens coating layer and the substrate is less than 0.01 degrees, and the flatness is less than 5 nanometers.

7. The lens according to claim 5, characterized in that: In the lens, the deviation of the arc of the cross section of the arc surface along the coating layer direction from the ideal circular arc does not exceed 1%; The surface roughness of the arc surface is less than 2 microns.

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