JP2020056684A - X-ray phase imaging device and method for manufacturing x-ray phase imaging device - Google Patents

Abstract

To provide an X-ray phase imaging device which can prevent a phase contrast image from becoming unclear due to an insufficient transmission of an X-ray in a lattice, the phase contrast image being generated according to a signal detected by a detector.SOLUTION: An X-ray phase imaging device 100 includes: an X-ray source 1; a detector 5 detecting an X-ray; and a plurality of lattices arranged between the X-ray source 1 and the detector 5. Each lattice includes lattice body members (20, 30, and 40) having surfaces (one-side surfaces 22, 32, and 42) with a plurality of recessed parts (21, 31, 41) and having back surfaces (other-side surfaces 23, 33, 43). Each lattice also includes resin substrates (high-transmission substrates 24, 34, and 44) deposited on the surfaces (22, 32, and 42), the resin substrates having a higher transmittance for X-rays than the lattice body members (20, 30, and 40) do.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an X-ray phase imaging apparatus, and more particularly to an X-ray phase imaging apparatus having a plurality of gratings and a method for manufacturing the X-ray phase imaging apparatus.

  2. Description of the Related Art Conventionally, an X-ray phase imaging device including a plurality of gratings and a method of manufacturing the X-ray phase imaging device are known (for example, see Patent Document 1).

  The X-ray phase imaging apparatus of Patent Document 1 includes an X-ray source, an X-ray image detector for detecting X-rays, a first diffraction grating provided between the X-ray source and the X-ray image detector, A second diffraction grating, a third diffraction grating, and an image processing unit are provided. Each of the first diffraction grating, the second diffraction grating, and the third diffraction grating is formed by a silicon substrate. Further, a plurality of slit grooves are provided on one surface of each of the first diffraction grating, the second diffraction grating, and the third diffraction grating. By adjusting the wavelength of the X-rays and the pitch width of the plurality of slit grooves, the first diffraction grating functions to diffract the irradiated X-rays, and forms a Talbot image (self-image).

  A substrate portion having a predetermined thickness is provided between the other surface of the second diffraction grating (third diffraction grating) and the slit groove. The plurality of slit grooves are filled with a metal that functions to absorb X-rays. Thereby, each of the second diffraction grating and the third diffraction grating is configured such that silicon that transmits X-rays and metal that absorbs X-rays are alternately arranged by providing a plurality of slit grooves. Have been. As a result, the third diffraction grating has a multi-slit shape and functions as a source grating. Further, an image contrast of Moire fringes is formed by interference between the Talbot image (self-image) formed by the first diffraction grating and the second diffraction grating, and the formed image contrast is detected by the X-ray image detector. .

Japanese Patent No. 5585662

  In the conventional X-ray phase imaging apparatus described in Patent Document 1, the thicknesses of the first diffraction grating, the second diffraction grating, and the third diffraction grating in the direction in which the X-ray optical axis extends are relatively large. For example, when the size is large, X-rays may not be sufficiently transmitted through the silicon substrate (particularly, the substrate portion), and the signal amount of the X-rays detected by the X-ray image detector may be excessively small. In this case, there is a problem that the contrast does not appear clearly in the phase contrast image generated based on the signal detected by the X-ray image detector, and the phase contrast image becomes unclear.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a method for detecting an X-ray by a detector due to insufficient transmission of X-rays through a grating. An object of the present invention is to provide an X-ray phase imaging apparatus and a method for manufacturing the X-ray phase imaging apparatus, which can prevent a phase contrast image generated based on a received signal from being blurred.

  To achieve the above object, an X-ray phase imaging apparatus according to a first aspect of the present invention includes an X-ray source, a detector for detecting X-rays emitted from the X-ray source, an X-ray source and a detector. A first grating for forming a self-image by X-rays emitted from an X-ray source, and a second grating for causing interference with the self-image of the first grating. And, each of the plurality of grids includes a grid body member having one side surface provided with a plurality of grooves and the other side surface provided on the side opposite to the one side surface, and includes a plurality of grids. At least one of the layers is laminated on at least one of the one surface and the other surface of the lattice body member, and includes a high-transmittance substrate having a higher X-ray transmittance than the lattice body member.

  In the X-ray phase imaging apparatus according to the first aspect of the present invention, as described above, at least one of the plurality of gratings is provided on at least one of the one surface and the other surface of the grating body member. It includes a highly transparent substrate that is stacked and has a higher light transmittance than the lattice body member. Thereby, the mechanical strength of the grating can be improved by the thickness of the highly permeable substrate, so that the grating main body member can be easily thinned. In this case, the high-transmittance substrate has a higher X-ray transmittance than the lattice main body member. Therefore, by laminating the high-permeability members and reducing the thickness of the lattice main body member, the lattice main body member is not thinned. The transmittance of the entire grating can be easily increased as compared with the conventional configuration in which the high transmittance members are not laminated. As a result, it is possible to suppress the phase contrast image generated based on the signal detected by the detector from being blurred due to insufficient transmission of X-rays in the grating.

  In the X-ray phase imaging device according to the first aspect, preferably, the highly transparent substrate includes at least one of a resin and carbon. Here, since resin and carbon have relatively high transmittance of X-rays, phase contrast generated based on a signal detected by the detector due to insufficient transmission of X-rays in the grating. It is possible to effectively suppress the image from becoming unclear.

  In the X-ray phase imaging apparatus according to the first aspect, preferably, the grating body member is made of silicon. Here, silicon is a material generally used conventionally as a material constituting the lattice, and has a lower X-ray transmittance than resin and carbon. Therefore, in the case where the highly permeable substrate contains resin, carbon, or the like, by laminating the highly permeable substrate and thinning the lattice body member made of silicon, the transmittance of X-rays as the entire lattice can be easily increased. Can be higher.

  In the X-ray phase imaging apparatus according to the first aspect, preferably, 方向 of the depth of the plurality of grooves is smaller than the thickness of the highly transparent substrate in the direction in which the optical axis of the X-ray extends. According to this structure, the transmittance of the X-rays in the portion of the lattice body constituting the plurality of grooves is reduced as compared with the case where １ ／ of the depth of the plurality of grooves is larger than the thickness of the highly permeable substrate. Can be higher.

  In the X-ray phase imaging apparatus according to the first aspect, it is preferable that a distance between an end of the plurality of grooves on the other surface side and the other surface is high transmission in a direction in which an X-ray optical axis extends. Smaller than the thickness of the flexible substrate. According to this structure, the thickness of the portion having a relatively small X-ray transmittance (the portion between the end of the groove and the other surface) is changed to the high transmittance substrate having a relatively high X-ray transmittance. , The X-ray transmittance of the entire grating can be further increased.

  In the X-ray phase imaging apparatus according to the first aspect, preferably, the high transmittance substrate includes a first high transmittance substrate provided on the first grating and a second high transmittance substrate provided on the second grating. Including. With this configuration, the transmittance of X-rays as a whole of the plurality of gratings is higher than in the case where only one of the first high-transmittance substrate and the second high-transmittance substrate is provided. can do.

  In the X-ray phase imaging apparatus according to the first aspect, preferably, the highly transparent substrate is laminated on both the one surface and the other surface. According to this structure, the thickness of the entire grid can be increased as compared with the case where the highly permeable substrate is laminated on one of the one surface and the other surface. The mechanical strength can be further improved.

  In addition, unlike the case where the highly permeable substrate is laminated on one of the one surface and the other surface, the stress applied from both ends of the lattice body member is balanced. As a result, the stress applied to the lattice body member can be reduced, and the lattice body member can be prevented from being warped.

  In this case, preferably, the highly permeable substrate laminated on one surface and the highly permeable substrate laminated on the other surface are adhered to each other with the lattice body member held therebetween. With this configuration, the mechanical strength of the entire lattice is higher than when the highly transparent substrate laminated on one surface and the highly transparent substrate laminated on the other surface are not bonded to each other. Can be further improved.

  In the X-ray phase imaging apparatus in which the highly transparent substrate on one side surface and the highly transparent substrate on the other side surface are bonded to each other, preferably, when viewed from the direction in which the X-ray optical axis extends, Each of the laminated high-transmittance substrate and the high-transmittance substrate laminated on the other surface has a protruding surface that protrudes from the lattice body member and is adhered to each other. With such a configuration, the high-transmittance substrates can be easily bonded to each other by the provision of the protruding surface.

  In the X-ray phase imaging apparatus according to the first aspect, preferably, the plurality of gratings are arranged between the X-ray source and the first grating to enhance coherence of X-rays emitted from the X-ray source. And a third grating for at least one of the first grating, the second grating, and the third grating including a highly transparent substrate. With this configuration, the transmission of the X-rays as a whole of the plurality of gratings can be improved as compared with the case where the highly transparent substrate is not provided in any of the first grating, the second grating, and the third grating. The rate can be easily increased.

  A method of manufacturing an X-ray phase imaging apparatus according to a second aspect of the present invention is a method of manufacturing a X-ray phase imaging apparatus, comprising: a plurality of grating main body members arranged between an X-ray source and a detector for detecting X-rays emitted from the X-ray source. Forming a plurality of grooves on one surface of the other, forming the other surface by thinning the lattice body member on the side opposite to the one surface, and forming at least one of the plurality of lattices. Laminating a highly transparent substrate having a higher light transmittance than the lattice body member on at least one of the one surface and the other surface of the lattice body member.

  In the method for manufacturing an X-ray phase imaging apparatus according to the second aspect of the present invention, as described above, the step of forming the other surface by thinning the grating main body member, and the step of forming one of the one surface and the other surface And laminating a highly transparent substrate having a higher light transmittance than the lattice body member. Thereby, while adjusting the thickness of the grid main body member to be thinned in the step of thinning the grid main body member, and adjusting the thickness of the highly permeable substrate laminated in the step of laminating the highly permeable substrate, The entire thickness can be easily adjusted, and the transmittance of the entire grating can be easily adjusted. As a result, the grating (X-ray phase imaging apparatus) is manufactured by a conventional manufacturing method in which the step of thinning the grating main body member and the step of laminating the highly transparent members are not performed while improving the mechanical strength of the entire grating. The transmittance of the entire grating can be easily increased as compared with the case of performing the above. This makes it possible to suppress the phase contrast image generated based on the signal detected by the detector from being blurred due to insufficient transmission of the X-rays in the grating. A method for manufacturing a phase imaging device can be provided.

  In the method of manufacturing an X-ray phase imaging apparatus according to the second aspect, preferably, the step of forming the other surface is configured so that the grating main body member is thinned by polishing. According to this structure, the lattice main body member is mechanically thinned by polishing, so that the amount (thickness) to be thinned can be accurately adjusted by controlling the polishing apparatus. As a result, the X-ray transmittance of the entire grating can be adjusted with high accuracy.

  In the method of manufacturing an X-ray phase imaging apparatus according to the second aspect, preferably, the step of forming the other surface is performed after the step of laminating a highly transparent substrate on the one surface. . With this configuration, when the other surface is formed, the thickness of the entire grating is increased by the thickness of the highly transparent substrate. As a result, the step of forming the other surface by thinning can be performed in a state where the mechanical strength of the lattice is high, so that the thinning step can be simplified. As a result, the thinning process can be performed so that the thickness of the lattice main body member becomes smaller.

  In this case, preferably, the step of forming the other surface includes a step of increasing a distance between an end of the plurality of grooves on the other surface side and the other surface by a high transmittance in a direction in which the optical axis of the X-ray extends. It is configured to be smaller than the thickness of the substrate. According to this structure, the thickness of the portion having a relatively small X-ray transmittance (the portion between the end of the groove and the other surface) is changed to the high transmittance substrate having a relatively high X-ray transmittance. , The X-ray transmittance of the entire grating can be further increased.

  According to the present invention, as described above, the phase contrast image generated based on the signal detected by the detector becomes unclear due to insufficient transmission of X-rays through the grating. Can be suppressed.

FIG. 1 is a diagram illustrating a configuration of an X-ray phase imaging apparatus according to an embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of a second grating of the X-ray phase imaging apparatus according to one embodiment. FIG. 4 is a flowchart illustrating a method for manufacturing an X-ray phase imaging apparatus (a plurality of gratings) according to an embodiment. FIG. 4 is a diagram illustrating a state of a lattice in each step of the flow in FIG. 3. FIG. 9 is a diagram for explaining an experimental result showing a relationship between a tube output and an amount of light reaching a detector. FIG. 9 is a cross-sectional view illustrating a configuration of an X-ray phase imaging device according to a first modification of the embodiment. FIG. 11 is a cross-sectional view illustrating a configuration of an X-ray phase imaging device according to a second modification of the embodiment. FIG. 10 is a cross-sectional view illustrating a configuration of an X-ray phase imaging device according to a third modification of the embodiment. It is the figure which looked at the X-ray phase imaging device by the 3rd modification of one embodiment from the direction where the optical axis of X-rays extended.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[This embodiment]
The configuration of the X-ray phase imaging apparatus 100 according to the present embodiment will be described with reference to FIGS.

(Configuration of X-ray phase imaging apparatus)
As shown in FIG. 1, the X-ray phase imaging apparatus 100 is an apparatus that images the inside of the subject T using the phase difference of X-rays that have passed through the subject T. Specifically, the X-ray phase imaging apparatus 100 is an apparatus that images the inside of the subject T using the Talbot effect. The X-ray phase imaging apparatus 100 is used, for example, in medical applications as an examination / diagnosis apparatus for rheumatism, breast cancer, lung cancer, and the like. The X-ray phase imaging apparatus 100 is used for observing and analyzing a new material such as a biomaterial and a resin in a nondestructive inspection application, for example.

  FIG. 1 is a diagram of the X-ray phase imaging apparatus 100 viewed from the X direction. As shown in FIG. 1, the X-ray phase imaging apparatus 100 includes an X-ray source 1, a first grating 2, a second grating 3, a third grating 4, and a detector 5. The subject T is provided between the first grid 2 and the second grid 3. In this specification, a direction from the X-ray source 1 toward the first grating 2 is defined as a Z2 direction, and a direction opposite thereto is defined as a Z1 direction. In addition, a left-right direction in a plane orthogonal to the Z direction is defined as an X direction, a direction toward the back of the paper is defined as an X2 direction, and a direction toward the near side of the paper is defined as an X1 direction. In addition, a vertical direction in a plane orthogonal to the Z direction is defined as a Y direction, an upward direction is defined as a Y1 direction, and a downward direction is defined as a Y2 direction. Note that FIG. 1 is a schematic diagram, and the size (the ratio of the size of each part) of the first grating 2, the second grating 3, and the third grating 4 is different from the actual one.

  The X-ray source 1 is configured to generate X-rays when a high voltage is applied, and to irradiate the generated X-rays in the Z2 direction.

  The first grating 2 is arranged between the X-ray source 1 and the second grating 3, and is irradiated with X-rays from the X-ray source 1. The first grating 2 is a so-called phase grating. The first grating 2 is provided to form a self-image (not shown) of the first grating 2 by the Talbot effect. When the coherent X-rays pass through the grid in which the slit is formed, an image (self-image) of the grid is formed at a position separated from the grid by a predetermined distance (Talbot distance). This is called the Talbot effect.

  The second grating 3 is disposed between the first grating 2 and the detector 5, and is irradiated with X-rays that have passed through the first grating 2. The second grating 3 is a so-called absorption grating. The second grating 3 is arranged at a position away from the first grating 2 by a Talbot distance. The second grating 3 interferes with the self-image of the first grating 2 and forms moiré fringes (not shown) on the detection surface of the detector 5.

  The third grating 4 is arranged between the X-ray source 1 and the first grating 2. The third grating 4 is a so-called multi-slit. The third grating 4 is configured to convert the X-rays from the X-ray source 1 into a multi-point light source. When the pitch of the three gratings (the first grating 2, the second grating 3, and the third grating 4) and the distance between the gratings satisfy certain conditions, the X-rays emitted from the X-ray source 1 It is possible to increase coherence. Thereby, the interference intensity can be maintained even if the focal size of the tube of the X-ray source 1 is large.

  The detector 5 is configured to detect an X-ray, convert the detected X-ray to an electric signal, and read the converted electric signal as an image signal. The detector 5 is, for example, an FPD (Flat Panel Detector). The detector 5 includes a plurality of conversion elements (not shown) and pixel electrodes (not shown) arranged on the plurality of conversion elements. The plurality of conversion elements and the pixel electrodes are arranged in an array in the X direction and the Y direction at a predetermined cycle (pixel pitch). The detector 5 is configured to output the acquired image signal to an image processing unit (not shown).

(Configuration of multiple grids)
Here, the configuration of each of the plurality of gratings (the first grating 2, the second grating 3, and the third grating 4) will be described.

  The first grating 2, the second grating 3, and the third grating 4 include a grating body member 20, a grating body member 30, and a grating body member 40, respectively. The lattice body member 20 has a front surface 22 provided with a plurality of grooves 21 and a back surface 23 provided on the opposite side to the front surface 22. The lattice main body member 30 has a front surface 32 provided with a plurality of grooves 31 and a back surface 33 provided on the opposite side to the front surface 32. The lattice body member 40 has a front surface 42 provided with a plurality of grooves 41 and a back surface 43 provided on the opposite side to the front surface 42. Each of the surface 22, the surface 32, and the surface 42 is a surface on the X-ray source 1 side. Each of the back surface 23, the back surface 33, and the back surface 43 is a surface on the detector 5 side. In addition, the surface 22, the surface 32, and the surface 42 are each an example of "one side surface" in the claims. The back surface 23, the back surface 33, and the back surface 43 are each an example of the “other surface” in the claims.

  Here, in the present embodiment, the first lattice 2 includes a resin substrate 24 laminated on the surface 22 of the lattice main body member 20. Further, the second lattice 3 includes a resin substrate 34 laminated on the surface 32 of the lattice main body member 30. Third lattice 4 includes a resin substrate 44 laminated on surface 42 of lattice main body member 40. The resin substrate 24 has a higher X-ray transmittance than the lattice main body member 20. The resin substrate 34 has a higher X-ray transmittance than the lattice main body member 30. The resin substrate 44 has a higher X-ray transmittance than the lattice body member 40. The resin substrate 24, the resin substrate 34, and the resin substrate 44 are each an example of the “highly transparent substrate” in the claims. The resin substrate 24 and the resin substrate 34 are examples of the “first high-transmittance substrate” and the “second high-transmittance substrate” in the claims, respectively.

  Specifically, the resin substrate 24 is bonded to the surface 22 of the lattice main body member 20 with an adhesive. The resin substrate 34 is bonded to the surface 32 of the lattice main body member 30 with an adhesive. The resin substrate 44 is adhered to the surface 42 of the lattice main body member 40 with an adhesive. Note that a lens adhesive having a small shrinkage rate may be used as the adhesive.

  Here, in the present embodiment, each of the resin substrates 24, 34, and 44 is made of epoxy resin, polyimide, polypropylene, ABS, polycarbonate, vinyl chloride, acrylic, polyethylene, polyethylene terephthalate (PET), polytetrafluoroethylene, Nylon, polyphenylene sulfide (PPS), polyetheretherketone (PEEK) and the like are considered as materials. The lattice body members (20, 30, 40) are made of silicon.

  The plurality of grooves 31 are filled with metal 35 (for example, gold). Further, a metal 45 (for example, gold) is buried in the plurality of grooves 41. Each of the metal 35 and the metal 45 functions to absorb X-rays. Each of metal 35 and metal 45 is formed by, for example, an electrolytic plating method described later. Note that the plurality of grooves 21 are not filled with metal. That is, the plurality of grooves 21 are filled with air.

  In addition, since the resin substrate 34 (44) is laminated on the surface 32 (42), it is possible to suppress the metal 35 (45) from floating from the groove 31 (41).

(Structure of lattice)
Next, the configuration of the second grating 3 will be described with reference to FIG. For the first grating 2 and the third grating 4, a detailed description of portions common to the configuration of the second grating 3 is omitted.

  In the present embodiment, as shown in FIG. 2, in the direction in which the optical axis of the X-rays extends (the Z direction), １ ／ of the depth D of the plurality of grooves 31 is smaller than the thickness t of the resin substrate 34. The depth of the plurality of grooves 31 means the length of the grooves 31 in the direction in which the optical axis of the X-rays extends (Z direction). Specifically, the thickness t of the resin substrate 34 is not less than 100 μm and not more than 1000 μm. Further, the depth D of the plurality of grooves 31 is 300 μm or less.

  In the direction in which the optical axis of the X-rays extends (the Z direction), the depth (not shown) of the plurality of grooves 21 is 1 μm or more and 40 μm or less. That is, in the direction (the Z direction) in which the optical axis of the X-ray extends (延 び る direction), １ ／ of the depth (not shown) of the plurality of grooves 21 is greater than the thickness (100 μm or more and 1000 μm or less, not shown) of the resin substrate 24. Is also small. In the direction in which the optical axis of the X-rays extends (Z direction), the depth (not shown) of the plurality of grooves 21 is smaller than the thickness (100 μm or more and 1000 μm or less, not shown) of the resin substrate 24. In the direction (Z direction) in which the optical axis of the X-ray extends (Z direction), the depth (not shown) of the plurality of grooves 41 is 300 μm or less, and ３ of the depth of the plurality of grooves 41 is the resin substrate. 44 (100 μm or more and 1000 μm or less, not shown).

  The second grating 3 is a lamella structure in which a plurality of grooves 31 are periodically provided on the surface 32. The period p of the plurality of grooves 31 is not less than 2 μm and not more than 100 μm. Further, when the width of each of the plurality of grooves 31 is a width W, the aspect ratio (D / W) of the grooves 31 is 3 or more and 100 or less.

  In the present embodiment, the distance d1 between the back surface 33 and the end 31a of the plurality of grooves 31 on the back surface 33 side is determined by the thickness t of the resin substrate 34 in the direction in which the X-ray optical axis extends (Z direction). Less than. In other words, the thickness (distance d1) of the lattice body member 30 on the detector 5 side (Z2 direction side) with respect to the plurality of grooves 31 is smaller than the thickness t of the resin substrate 34. Specifically, while the thickness t of the resin substrate 34 is 100 μm or more and 1000 μm or less as described above, the distance d1 is 50 μm or less.

  The back surface 33 is a surface formed by polishing (rough polishing, lapping) the grating main body member 30 to make it thinner. That is, the lattice main body member 30 is polished (thinned) so that the distance d1 is 50 μm or less.

  Next, a method for manufacturing the second grating 3 will be described with reference to FIG. Since the manufacturing method is also common among the plurality of gratings, description of the first grating 2 and the third grating 4 is omitted.

First, in step S1 (see S1 in FIG. 4), a plurality of grooves 31 are formed on the surface 32 of the lattice main body member 30. Specifically, first, a periodic groove portion 31 is formed (patterned) by DRIE (Deep Reactive Ion Etching). Next, an insulating layer (SiO ₂ film) is formed on the surface of the groove 31 (and the surface 32 of the lattice body member 30) by a thermal oxidation method or the like.

  At the stage of step S1, the distance d2 between the end 31a and the back surface 33a of the second grating 3 is about 600 μm to 700 μm. That is, the distance d2 is ten times or more the distance d1 (see FIG. 2).

  Next, in step S2 (see S2 in FIG. 4), the metal 35 is formed in each of the plurality of grooves 31. Specifically, first, the insulating layer on the bottom surface 31b (the surface on the side of the end portion 31a, see FIG. 2) of each of the plurality of grooves 31 is removed by an ICP (Inductive Coupled Plasma) dry etching method or the like. Next, the plurality of grooves 31 are filled with metal 35 by an electrolytic plating method. Specifically, the metal 35 is deposited from the bottom surface 31 b of the groove 31 by applying a voltage to the lattice main body member 30. Then, by growing the deposited metal 35, the groove 31 is filled with the metal 35. This step is not performed on the first grating 2.

  Next, in step S3 (see S3 in FIG. 4), a resin substrate 34 is laminated on the surface 32 of the lattice main body member 30. Then, in step S4 (see S4 in FIG. 4), the back surface 33 is formed by polishing and thinning the lattice body member 30 on the side opposite to the front surface 32. In step S4, the distance d1 (see FIG. 2) between the end 31a of the plurality of grooves 31 on the rear surface 33 side and the rear surface 33 is determined by the distance (Z direction) of the resin substrate 34 in the direction in which the X-ray optical axis extends (Z direction). The back surface 33 is formed by reducing the thickness of the lattice main body member 30 so as to be smaller than the thickness t (see FIG. 2).

(Experimental result)
Next, with reference to FIG. 5, an experimental result of measuring the amount of light reaching the detector 5 by the material of the grating body members (20, 30, 40) will be described.

  As shown in FIG. 5, when each of the first grating 2, the second grating 3, and the third grating 4 is made of a carbon (C) substrate (see a broken line), the amount of light reaching the detector 5 It was confirmed that each of the first grating 2, the second grating 3, and the third grating 4 was larger than the light quantity when each of the first grating 2, the third grating 4, and the third grating 4 was made of silicon (Si) (see a dashed line). Specifically, when comparing the integrated values of the light amounts when the tube power is from 10 kW to 40 kW, the integrated value when the grating is carbon is 3.6 times the integrated value when the grating is silicon. In particular, when the output of the tube (not shown) of the X-ray source 1 was relatively small, it was confirmed that the light amount when the grating was silicon was significantly larger than the light amount when the grating was carbon. . The thickness of each lattice of silicon and each lattice of carbon are the same.

  In addition, it was confirmed that the tube output at which the peak of the amount of light appeared when the grating was carbon changed (decreased) with respect to the tube output at which the peak appeared when the grating was silicon. That is, it was confirmed that the quality of the X-rays reaching the detector 5 was changed depending on the material of the grating. In addition, a result was obtained in which the tube output at which the peak of the amount of light appeared when the lattice was carbon was substantially equal to the tube output at which the peak of the spectrum (tungsten spectrum, see the solid line) immediately after output from the tube appeared. . That is, it was confirmed that when the plurality of gratings were carbon substrates, it was possible to reach the detector 5 without greatly changing the quality of X-rays output from the tube of the X-ray source 1. . Regarding the light amount, it was confirmed that the light amount detected by the detector 5 when the grating was made of carbon did not largely change from the light amount immediately after output from the tube of the X-ray source 1. Further, even if a resin substrate is used instead of the carbon substrate, the same result can be obtained since the resin substrate is substantially made of carbon (carbon).

  From these results, by thinning the lattice body members (20, 30, 40) made of silicon and laminating the resin substrates (24, 34, 44), the amount of X-rays reaching the detector 5 becomes excessive. It has been found that it is possible to suppress the change in the quality of X-rays due to the transmission through the grating, as well as to suppress the change in the quality of X-rays.

(Effect of this embodiment)
In the present embodiment, the following effects can be obtained.

  In the present embodiment, as described above, each of the plurality of grids (the first grid 2, the second grid 3, and the third grid 4) is formed on the surface (22, 32, 40) of the grid body member (20, 30, 40). The X-ray phase imaging apparatus 100 is configured so as to include a resin substrate (24, 34, 44) that is stacked on the base material 42) and has a higher X-ray transmittance than the grating body members (20, 30, 40). Thereby, the mechanical strength of the second grid 3 can be improved by the thickness t of the resin substrate 34, so that the grid main body member 30 can be easily thinned. In this case, since the resin substrate 34 has a higher X-ray transmittance than the lattice main body member 30, the lattice main body member 30 is not reduced in thickness by laminating the resin substrate 34 and reducing the thickness of the lattice main body member 30. In addition, the transmittance of the second grating 3 as a whole can be easily increased as compared with the conventional configuration in which the resin substrate 34 is not laminated. As a result, it is possible to prevent the phase contrast image generated based on the signal detected by the detector 5 from becoming unclear due to insufficient transmission of X-rays in the second grating 3. it can. The same effect can be obtained in each of the first grating 3 and the third grating 4.

  Further, since the resin has a relatively high transmittance of X-rays, a phase contrast image generated based on a signal detected by the detector 5 is generated due to insufficient transmission of X-rays in the grating. Blurring can be effectively suppressed.

  In the present embodiment, as described above, the X-ray phase imaging apparatus 100 is configured such that the grating main body members (20, 30, 40) are formed of silicon. Here, silicon is a material generally used conventionally as a material constituting the lattice, and has a lower X-ray transmittance than resin and carbon. Therefore, when the resin substrates (24, 34, 44) contain resin or carbon, the lattice body members (20, 30, 40) formed by laminating the resin substrates (24, 34, 44) and silicon are used. By making the film thin, the transmittance of X-rays as a whole of the grating (2, 3, 4) can be easily increased.

  Further, in the present embodiment, as described above, in the direction in which the optical axis of the X-ray extends, one-third of the depth D of the plurality of grooves 31 is smaller than the thickness t of the resin substrate 34. The phase imaging apparatus 100 is configured. Thereby, the transmittance of the X-rays in the portion of the lattice body member 30 that forms the plurality of grooves 31 is reduced as compared with the case where ３ of the depth D of the plurality of grooves 31 is larger than the thickness t of the resin substrate 34. Can be higher. The same effect can be obtained in each of the first grating 3 and the third grating 4.

  Further, in the present embodiment, as described above, the distance d1 between the end 31a of the plurality of grooves 31 on the back surface 33 side and the back surface 33 is determined by the thickness of the resin substrate 34 in the direction in which the X-ray optical axis extends. The X-ray phase imaging apparatus 100 is configured to be smaller than t. Thereby, the thickness of the portion having a relatively small X-ray transmittance (the portion between the end 31a of the groove 31 and the back surface 33) is made larger than the thickness t of the resin substrate 34 having the relatively high X-ray transmittance. Since the size can be reduced, the transmittance of X-rays as the whole second grating 3 can be further increased. The same effect can be obtained in the first grating 3 and the third grating 4.

  In the present embodiment, as described above, the X-ray phase imaging apparatus 100 is configured such that the resin substrate 24 provided on the first grating 2 and the resin substrate 34 provided on the second grating 3 are provided. . This makes it possible to increase the transmittance of X-rays as a whole of the plurality of gratings as compared with the case where only one of the resin substrate 24 and the resin substrate 34 is provided.

  In the present embodiment, as described above, the first grating 2, the second grating 3, and the third grating 4 include the resin substrate 24, the resin substrate 34, and the resin substrate 44, respectively. The X-ray phase imaging apparatus 100 is configured. This facilitates the transmission of X-rays as a whole of the plurality of gratings, compared to a case where no resin substrate is provided on any of the first grating 2, the second grating 3, and the third grating 4. Can be higher. Further, compared to the case where only one or two of the first grating 2, the second grating 3, and the third grating 4 are provided with the resin substrate, the X-rays as a whole of the plurality of gratings are compared. Can be easily increased.

  In the present embodiment, as described above, the steps of forming the back surfaces (23, 33, 43) by thinning the lattice main body members (20, 30, 40), and the steps of forming the lattice main body members (20, 30, 40), a step of laminating the resin substrates (24, 34, 44) on the surfaces (22, 32, 42). Thereby, in the step of thinning the lattice body members (20, 30, 40), the thickness of the lattice body members (20, 30, 40) to be thinned is adjusted, and the lamination of the resin substrates (24, 34, 44) is performed. By adjusting the thickness of the resin substrates (24, 34, 44) laminated in the step (1), the entire thickness of the grid (2, 3, 4) can be easily adjusted and the grid (2, 3, 4) can be easily adjusted. 3.) The overall transmittance can be easily adjusted. As a result, a step of reducing the thickness of the grid main body member (20, 30, 40) and a step of laminating the resin substrates (24, 34, 44) while improving the mechanical strength of the entire grid (2, 3, 4). The transmittance of the entire grating (2, 3, 4) is easily increased as compared with the case where the grating (2, 3, 4) (X-ray phase imaging apparatus 100) is manufactured by a conventional manufacturing method in which the above-described process is not performed. be able to. This prevents the phase contrast image generated based on the signal detected by the detector 5 from being blurred due to insufficient transmission of the X-rays in the grating (2, 3, 4). It is possible to provide a method of manufacturing the X-ray phase imaging apparatus 100 that can suppress the X-ray phase imaging apparatus 100.

  Further, in the present embodiment, as described above, the step of forming the back surface (23, 33, 43) is performed such that the grating body members (20, 30, 40) are thinned by polishing, so that the X-ray phase is reduced. The manufacturing method of the imaging apparatus 100 is configured. Thereby, since the grating main body members (20, 30, 40) are mechanically thinned by polishing, the amount (thickness) of thinning can be accurately adjusted by controlling the polishing apparatus. As a result, it is possible to accurately adjust the transmittance of X-rays of the entire grating (2, 3, 4).

  In this embodiment, as described above, the step of forming the back surface (23, 33, 43) is performed after the step of laminating the resin substrate (24, 34, 44) on the front surface (22, 32, 42). The manufacturing method of the X-ray phase imaging apparatus 100 is configured to be performed. Thereby, when forming the back surface (23, 33, 43), the thickness of the entire lattice (2, 3, 4) is increased by the thickness of the resin substrate (24, 34, 44). As a result, the process of forming the back surface (23, 33, 43) by thinning can be performed in a state where the mechanical strength of the grating (2, 3, 4) is high, thereby facilitating the process of thinning. be able to. As a result, a thinning process can be performed so that the thickness of the lattice main body member (20, 30, 40) becomes smaller.

  Further, in the present embodiment, as described above, the step of forming the back surface 33 is such that the distance d1 between the end 31a of the plurality of grooves 31 on the back surface 33 side and the back surface 33 is determined by the optical axis of the X-ray. The manufacturing method of the X-ray phase imaging apparatus 100 is configured so as to be smaller than the thickness t of the resin substrate 34 in the extending direction. Thereby, the thickness of the portion having a relatively small X-ray transmittance (the portion between the end 31a of the groove 31 and the back surface 33) is made larger than the thickness t of the resin substrate 34 having the relatively high X-ray transmittance. Since the size can be reduced, the transmittance of X-rays as the whole second grating 3 can be further increased. The same effect can be obtained in each of the first grating 3 and the third grating 4.

(Modification)
It should be understood that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is defined not by the description of the above-described embodiment but by the claims, and further includes meanings equivalent to the claims and all modifications (modifications) within the scope.

  For example, in the above-described embodiment, an example in which the resin substrate (24, 34, 44, high-permeability substrate) is laminated on the surface (22, 32, 42, one side surface) has been described. Not limited.

  For example, in the example shown in FIG. 6, in the second lattice 13, a resin substrate 134 is laminated on the back surface 133 of the lattice main body member 130. Although not shown, the same configuration may be applied to the first grating and the third grating. The back surface 133 and the resin substrate 134 are examples of the “other surface” and the “highly permeable substrate” in the claims, respectively.

  In this case, since the step of forming the back surface 133 (the step of thinning) is performed before the step of laminating the resin substrate 134, the gap between the end 31 a of the plurality of grooves 31 on the back surface 133 side and the back surface 133 is formed. Is greater than the depth D of the plurality of grooves 31. Specifically, the distance d3 is 200 μm or more.

  In the example shown in FIG. 7, in the second lattice 53, the resin substrate 234 a is laminated on the front surface 232 of the lattice main body member 230, and the resin substrate 234 b is laminated on the back surface 233 of the lattice main body member 230. Although not shown, the same configuration may be applied to the first grating and the third grating. The front surface 232 and the back surface 233 are examples of the “one surface” and the “other surface” in the claims, respectively. The resin substrate 234a and the resin substrate 234b are each an example of the “highly transparent substrate” in the claims.

  In this case, any of the resin substrate 234a and the resin substrate 234b may be laminated (adhered) to the lattice body member 230 first, but the step of laminating the resin substrate 234a, the step of thinning the lattice body member 230, and the step of resin substrate When the steps of stacking the 234b are performed in this order, the thickness of the lattice main body member 230 can be minimized.

  This makes it possible to increase the thickness of the second grating 53 as a whole, as compared with the case where the resin substrate is laminated on one of the front surface 232 and the back surface 233. Strength can be further improved. Note that the same effect can be obtained with the first grating and the third grating.

  Further, unlike the case where the resin substrate is laminated on one of the front surface 232 and the back surface 233, the stress applied from both ends of the lattice main body member 230 is balanced. As a result, the stress applied to the grid main body member 230 can be reduced, and the occurrence of warpage of the grid main body member 230 can be suppressed.

  In the example shown in FIG. 8, in the second lattice 63, the resin substrate 334 a is laminated on the front surface 332 of the lattice main body member 330, and the resin substrate 334 b is laminated on the back surface 333 of the lattice main body member 330. The resin substrate 334a and the resin substrate 334b are adhered to each other with the lattice body member 330 held therebetween. Although not shown, the same configuration may be applied to the first grating and the third grating. Further, the front surface 332 and the back surface 333 are examples of “one side surface” and “other side surface” in the claims, respectively. The resin substrate 334a and the resin substrate 334b are each an example of the “highly transparent substrate” in the claims.

  Specifically, as shown in FIG. 9, when viewed from the direction in which the optical axis of the X-rays extends (Z direction), the resin substrate 334a has a protruding surface 334c protruding from the lattice main body member 330. When viewed from the direction in which the optical axis of the X-ray extends, the resin substrate 334 b has a protruding surface 334 d protruding from the lattice main body member 330. The protruding surfaces 334c and 334d are provided so as to face each other. The projecting surface 334c and the projecting surface 334d are bonded to each other by applying an adhesive 335 (see FIG. 8) between the projecting surface 334c and the projecting surface 334d. Note that, in this case, the resin substrate 334a and the resin substrate 334b and the lattice body member 330 may not be bonded with an adhesive, or may be bonded.

  Thereby, the mechanical strength of the entire second lattice 63 is further improved as compared with the case where the resin substrate 334a laminated on the front surface 332 and the resin substrate 334b laminated on the rear surface 333 are not bonded to each other. be able to. Further, the provision of the protruding surfaces (334c, 334d) allows the resin substrate 334a and the resin substrate 334b to be easily bonded to each other. The same effect can be obtained in each of the first grating and the third grating.

  Further, in the above-described embodiment, the example in which the resin substrate (24, 34, 44, high-permeability substrate) is laminated on the lattice main body member (20, 30, 40) has been described, but the present invention is not limited to this. Absent. For example, a resin substrate may be laminated on any one or two of the first grating 2, the second grating 3, and the third grating 4.

  In the above embodiment, when the second grating 3 is taken as an example, a portion between the end portions 31a of the plurality of groove portions 31 and the back surface 33 (the surface on the other side) has a constant thickness (portion of the distance d1). However, the present invention is not limited to this. The portion between the end 31a of the plurality of grooves 31 and the back surface 33 (the other surface) may not be provided (that is, the distance d1 may be zero). Note that the first grating 2 and the third grating 4 may have the same configuration.

  Further, in the above-described embodiment, the example in which the resin substrates (24, 34, and 44, the high-transmittance substrates) are laminated by the adhesive has been described, but the present invention is not limited to this. For example, the resin substrates may be joined by heating and pressing. Alternatively, the resin substrates may be stacked using a 3D printer. Alternatively, the resin substrate may be formed by forming a resin film by spin coating and thermally curing the resin film. Further, the resin substrate may be formed by screen printing.

  Further, in the above-described embodiment, the example in which the resin substrates (24, 34, 44, high transmittance substrates) are laminated on the lattice main body members (20, 30, 40) has been described, but the present invention is not limited to this. For example, a carbon substrate may be laminated on the lattice body members (20, 30, 40). Examples of the carbon substrate include a graphite substrate, graphite sheet (graphite sheet), CFRP (carbon fiber reinforced plastic), C / C composite (carbon fiber reinforced carbon composite material), glassy carbon (glassy carbon / glassy carbon), and crystal. Graphite is considered as a material. Instead of a carbon substrate, a metal oxide and a metal nitride (for example, aluminum oxide, magnesium oxide, and aluminum nitride) may be stacked. Note that both the resin substrate and the carbon substrate may be laminated on the lattice main body member (20, 30, 40).

  In the above embodiment, the example in which the third grating 4 is provided has been described, but the present invention is not limited to this. The third grating 4 may not be provided.

  Further, in the above embodiment, the example in which the lattice main body members (20, 30, 40) are thinned by polishing has been described, but the present invention is not limited to this. For example, the grating body members (20, 30, 40) may be thinned by chemical etching or chemical mechanical polishing (CMP) using a polishing and polishing chemical reaction in combination.

DESCRIPTION OF SYMBOLS 1 X-ray source 2 1st grating 3, 13, 53, 63 2nd grating 4 3rd grating 5 Detector 20, 30, 40, 130, 230, 330 Grating body member 21, 31, 41 Groove part 22, 32, 42 , 232, 332 surface (one side surface)
23, 33, 43, 133, 233, 333 Back surface (other surface)
24 Resin substrate (highly transparent substrate) (first highly transparent substrate)
31a End (ends of multiple grooves)
34 Resin substrate (highly transparent substrate) (second highly transparent substrate)
44, 134, 234a, 234b, 334a, 334b Resin substrate (highly transparent substrate)
100 X-ray phase imaging device 334c, 334d Projection surface d1, d3 Distance (distance between end of groove and other surface)
D Depth (depth of multiple grooves)
t Thickness (thickness of highly transparent substrate)

Claims (14)

An X-ray source,
A detector for detecting X-rays emitted from the X-ray source;
A first grating arranged between the X-ray source and the detector for forming a self-image by the X-rays emitted from the X-ray source, and causing interference with a self-image of the first grating. And a plurality of grids, including:
Each of the plurality of lattices includes a lattice main body member having one surface provided with a plurality of grooves and another surface provided on the opposite side to the one surface,
At least one of the plurality of gratings is stacked on at least one of the one surface and the other surface of the grating body member, and has a higher X-ray transmittance than the grating body member. An X-ray phase imaging device including a highly transparent substrate.   The X-ray phase imaging apparatus according to claim 1, wherein the high-transmittance substrate includes at least one of a resin and carbon.   The X-ray phase imaging apparatus according to claim 1, wherein the grating main body member is made of silicon.   The X-ray according to any one of claims 1 to 3, wherein in the direction in which the optical axis of the X-ray extends, 1/3 of the depth of the plurality of grooves is smaller than the thickness of the highly transparent substrate. Phase imaging device.   2. The distance between an end of the plurality of grooves on the other surface side and the other surface is smaller than a thickness of the highly transparent substrate in a direction in which an optical axis of the X-ray extends. The X-ray phase imaging apparatus according to any one of claims 1 to 4.   The said high transmittance | permeability board | substrate contains the 1st high transmittance | permeability board | substrate provided in the 1st grating | lattice, and the 2nd high transmittance | permeability board | substrate provided in the 2nd grating | lattice. An X-ray phase imaging apparatus according to claim 1.   The X-ray phase imaging apparatus according to any one of claims 1 to 6, wherein the high transmittance substrate is laminated on both the one surface and the other surface.   The high-transmittance substrate stacked on the one-side surface and the high-transmittance substrate stacked on the other-side surface are adhered to each other while holding the lattice body member therebetween, according to claim 7, wherein An X-ray phase imaging apparatus according to claim 1.   When viewed from the direction in which the optical axis of the X-ray extends, each of the highly transparent substrate laminated on the one surface and the highly transparent substrate laminated on the other surface is the lattice body member. The X-ray phase imaging apparatus according to claim 8, wherein the X-ray phase imaging apparatus has a protruding surface that protrudes from and is adhered to each other. The plurality of gratings are further disposed between the X-ray source and the first grating, and further include a third grating for increasing coherence of X-rays emitted from the X-ray source,
The X-ray phase imaging apparatus according to claim 1, wherein at least one of the first grating, the second grating, and the third grating includes the highly transparent substrate. . Forming a plurality of grooves on one surface of a grating body member of a plurality of gratings disposed between an X-ray source and a detector for detecting X-rays emitted from the X-ray source;
On the side opposite to the one side surface, forming the other side surface by thinning the lattice body member,
A high-transmitting substrate having a higher light transmittance than the lattice body member on at least one of the one surface and the other surface of at least one lattice body member of the plurality of lattices. And a step of laminating the X-ray phase imaging apparatus.   The method of manufacturing an X-ray phase imaging apparatus according to claim 11, wherein the step of forming the other surface is configured to reduce the thickness of the grating body member by polishing.   The manufacturing of the X-ray phase imaging apparatus according to claim 11 or 12, wherein the step of forming the other surface is configured to be performed after the step of laminating the highly transparent substrate on the one surface. Method.   The step of forming the other-side surface includes the step of: setting a distance between an end of the plurality of grooves on the other-side surface side and the other-side surface to the high transmittance in a direction in which an optical axis of the X-ray extends. The method for manufacturing an X-ray phase imaging apparatus according to claim 13, wherein the X-ray phase imaging apparatus is configured to be smaller than a thickness of the substrate.

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