WO2013099652A1

WO2013099652A1 - Radiography grid, method for producing same, and radiography system

Info

Publication number: WO2013099652A1
Application number: PCT/JP2012/082463
Authority: WO
Inventors: 金子　泰久
Original assignee: 富士フイルム株式会社
Priority date: 2011-12-27
Filing date: 2012-12-14
Publication date: 2013-07-04
Also published as: JP2013134196A

Abstract

This grid is provided with a plurality of small grids (18-20) and a support substrate (23). The small grids (18-20) have: a flat plate-shaped ground substrate (31); and grid sections (32) that are formed on the ground substrate (31) and that form a striped image as a result of locally transmitting radiation radiated from the focal point of a radiation source. The support substrate (23) is formed from a flexible substrate (26) having flexibility and a glass substrate (27) having a lower coefficient of thermal expansion than the flexible substrate (26) being pasted together, and the small grids (18-20) are arrayed at a predetermined disposition on the glass substrate (27) in accordance with alignment marks provided on the glass substrate (26). After pasting each small grid (18-20) on, the support substrate (23) is bent in a manner so that each grid section (32) faces the focal point of the radiation source.

Description

Radiation imaging grid, manufacturing method thereof, and radiation imaging system

The present invention relates to a grid used for radiographic imaging, a manufacturing method thereof, and a radiographic imaging system using the grid.

It is known that radiation (for example, X-rays) changes in intensity and phase due to interaction with an object, and the phase change exhibits a higher interaction than the change in intensity. In recent years, attention has been paid to an X-ray imaging system that obtains a high-contrast image (hereinafter referred to as a phase contrast image) from a subject having a low X-ray absorption capacity based on a phase change of X-rays.

An X-ray imaging system for imaging a phase contrast image includes an X-ray source that irradiates X-rays, first and second grids, and a radiation image detector. A subject is placed between the X-ray source and the first grid, and while the first grid is moved intermittently, a plurality of fringe images whose intensity is modulated by superimposing the self-image of the first grid and the second grid are taken. Then, a phase contrast image is acquired based on a change caused by the subject superimposed on these fringe images. This X-ray image capturing method is called a fringe scanning method.

Also, since the X-ray source emits X-rays that spread like a cone beam, there is a problem that vignetting of X-rays occurs at the periphery of the grid when a flat grid is used. In order to reduce vignetting, it is preferable to make the grid curved in a cylindrical shape (or spherical shape) in accordance with the spread of X-rays, but the grid is formed using, for example, a silicon wafer. When a grid produced in a flat plate shape is curved, the grid may be damaged.

For this reason, for example, in Japanese Patent Application Laid-Open No. 2007-203061 (corresponding to US Pat. No. 7,522,698), a plurality of flat small grids are arranged on the concave surface to locally form a flat plate. A grid having a curved shape as a whole is disclosed. Japanese Patent Laid-Open No. 2010-063646 (corresponding US Pat. No. 8,139,711) describes forming a grid on a flexible substrate and then bending the flexible substrate into a cylindrical surface. Has been.

However, as described in Japanese Patent Application Laid-Open No. 2007-203061, when a small grid is arranged on a non-planar surface in accordance with the spread of X-rays, it is necessary to align the arrangement and inclination of each small grid with high accuracy. . However, Japanese Patent Laid-Open No. 2007-203061 does not disclose a specific method for aligning each small grid with high accuracy when the small grids are arranged on a non-planar surface. For this reason, it is difficult to arrange the small grid in a cylindrical surface or a spherical surface with high accuracy to the extent that it can be used for actual photographing.

In addition, since the flexible substrate has a large coefficient of thermal expansion and is easily deformed, as described in JP 2010-063646 A, when a grid is formed on the flexible substrate, the grid expands due to the thermal expansion of the flexible substrate. There is a problem that the accuracy of itself deteriorates.

Furthermore, if Japanese Patent Application Laid-Open No. 2007-203061 and Japanese Patent Application Laid-Open No. 2010-063646 are combined, it is conceivable that a small grid is attached on the flexible substrate to curve the flexible substrate. In this case, an alignment mark is provided as a guideline for placing a small grid on the flexible board, and the small grid is placed in accordance with the alignment mark. However, because of the thermal expansion coefficient and ease of deformation of the flexible board, In addition, since the interval between the alignment marks is easily changed, it is difficult to form the alignment marks with high accuracy. Therefore, when a small grid is arranged on a flexible substrate, it is necessary to use an alignment mark with low accuracy as a reference, so that there remains a problem that it is difficult to arrange with high accuracy.

An object of the present invention is to provide a grid in which small grids are arranged with high accuracy on a curved surface, a manufacturing method thereof, and a radiographic imaging system.

The radiation image capturing grid of the present invention includes a plurality of small grids and a support substrate. Each small grid includes a flat base substrate and a grid portion that is formed on the base substrate and generates a fringe image by partially transmitting the radiation emitted from the focal point of the radiation source. The support substrate is formed by bonding a flexible first substrate and a second substrate having a smaller coefficient of thermal expansion than the first substrate. The small grids are arranged in a predetermined arrangement on the second substrate according to the alignment marks provided on the second substrate. After arranging the small grids on the second substrate according to the alignment marks, the support substrate is curved so that the grid portion of each small grid faces the focal point of the radiation source.

The second substrate is a glass substrate and is divided according to the arrangement of the small grids as the support substrate is curved. The section of the second substrate after the division and the laminated body of each small grid are integrally held by the curved first substrate.

It is preferable that a groove for specifying a bent position of the support substrate is provided on the surface of the second substrate. For example, the grooves are formed in a perforation along the surface of the second substrate. For example, the groove is obtained by partially cutting the second substrate in the thickness direction. The groove may be formed by cutting the second substrate in the thickness direction. Thus, when providing a groove | channel on the surface of a 2nd board | substrate, it is preferable that the 1st board | substrate has the low rigidity part which reduced rigidity on the straight line corresponding to the groove | channel formed in a 2nd board | substrate.

A shape memory material can be used for the first substrate.

The small grid is, for example, an absorption grid having a grid portion formed by alternately arranging a radiation absorbing portion and a radiation transmitting portion. Further, the small grid may be a phase type grid having a grid portion formed by alternately arranging two kinds of members having radiation transparency.

The method for manufacturing a radiographic imaging grid according to the present invention includes a small grid manufacturing process, a support substrate forming process, a small grid attaching process, and a bending process. The small grid forming step includes a plurality of small grids each having a flat base substrate and a grid portion that is formed on the base substrate and generates a fringe image by partially transmitting the radiation irradiated from the focal point of the radiation source. Form. In the support substrate forming step, a first substrate having a parallel plate shape and a second substrate having a parallel plate shape having a thermal expansion coefficient smaller than that of the first substrate are bonded together to form a support substrate. In the small grid attaching step, the small grids are attached to the second substrate in a predetermined arrangement according to the alignment mark provided on the second substrate. In the bending step, the support substrate to which the small grid is attached is bent so that the grid portion of each small grid faces the focal point of the radiation source.

Furthermore, it is preferable to provide a groove forming step of providing a groove for specifying the bent position of the support substrate on the second substrate.

Moreover, it is preferable to provide a low-rigidity treatment step for forming a low-rigidity portion having low rigidity on the first substrate.

The radiographic imaging system has a first grid, a second grid, and a radiographic image detector. The first grid transmits a radiation emitted from the radiation source to generate a fringe image. The second grid applies intensity modulation to the fringe image. The radiation image detector detects a fringe image whose intensity is modulated by the second grid. Then, a phase contrast image is generated from the fringe image detected by the radiation image detector. In this radiographic imaging system, in the radiographic imaging system of the present invention, at least one of the first grid and the second grid includes a plurality of small grids and a support substrate. The small grid includes a flat base substrate and a grid portion that is formed on the base substrate and generates a fringe image by partially transmitting the radiation irradiated from the focal point of the radiation source. The support substrate is formed by bonding a flexible first substrate and a second substrate having a smaller coefficient of thermal expansion than the first substrate. The support substrate is curved so that the grid portions of each small grid face the focal point of the radiation source after the small grids are arranged in a predetermined arrangement according to the alignment marks provided on the second substrate.

A radiation source grid may be further provided that is disposed between the radiation source and the first grid and forms radiation on a large number of lines by selectively shielding the radiation irradiated from the radiation source. The radiation source grid preferably includes the plurality of small grids and a support substrate described above.

The present invention provides a support substrate after accurately arranging a small grid on a support substrate formed by bonding a flexible first substrate and a second substrate having a smaller coefficient of thermal expansion than the first substrate. And the small grid is aimed at the focal point of the radiation source. Thereby, this invention can arrange | position a small grid with high precision on the curved surface.

It is explanatory drawing which shows the structure of a X-ray imaging system. It is a top view of the 2nd grid. FIG. 3 is a cross-sectional view of a second grid taken along line III-III in FIG. 2. It is sectional drawing which shows the structure of a small grid. It is sectional drawing which shows the process of joining an X-ray transparent board | substrate and a base substrate. It is sectional drawing which shows the process of forming an etching mask in the surface of a X-ray transparent substrate. It is sectional drawing which shows the process of performing the dry etching which exposes a seeds layer. It is sectional drawing which shows the process of filling a groove | channel with an X-ray absorber by electrolytic plating. It is sectional drawing which shows the structure and manufacturing procedure of a support substrate. It is explanatory drawing which shows the process of providing a groove | channel and an alignment mark in a support substrate. It is explanatory drawing which shows the process of sticking a small grid on a support substrate. It is sectional drawing which shows the process of curving a support substrate. It is sectional drawing which shows the example which provides a low-rigidity part in a flexible substrate. It is sectional drawing which shows the example which provides another low-rigidity part. It is explanatory drawing which shows the example which formed the groove | channel formed in a glass substrate in the perforation shape. It is sectional drawing containing a groove | channel. It is sectional drawing containing a connection part. It is explanatory drawing which shows the example which provided the perforated groove | channel of the other aspect in the glass substrate. It is explanatory drawing which shows the correspondence of the groove | channel formed in a glass substrate, and the low-rigidity part formed in a flexible substrate. It is explanatory drawing which shows the correspondence of the groove | channel formed in a glass substrate, and the low-rigidity part formed in a flexible substrate. It is explanatory drawing which shows the correspondence of the groove | channel formed in a glass substrate, and the low-rigidity part formed in a flexible substrate. It is explanatory drawing which shows the correspondence of the groove | channel formed in a glass substrate, and the low-rigidity part formed in a flexible substrate. It is explanatory drawing which shows the example which curves and forms a grid in spherical shape. It is sectional drawing which shows the example which affixed the grid part on the glass substrate. It is sectional drawing which shows the example which fixes the curved grid to a base. It is sectional drawing which shows the example which put the filler in the clearance gap between small grids. It is sectional drawing which shows the example which uses a shape memory substrate instead of a flexible substrate. It is sectional drawing which shows the example which uses a composite substrate instead of a flexible substrate.

[First Embodiment]
As shown in FIG. 1, the X-ray imaging system 10 includes an X-ray source 11, a source grid 12, a first grid 13, a second grid 14, and an X-ray along the Z direction that is an X-ray irradiation direction. An image detector 15 is arranged.

The X-ray source 11 has a rotating anode type X-ray tube (not shown) and a collimator (not shown) for limiting the X-ray irradiation field, and emits X-rays to the subject H.

The radiation source grid 12, the first grid 13, and the second grid 14 are absorption grids that absorb X-rays, and are disposed to face the X-ray source 11 in the Z direction. The source grid 12, the first grid 13, and the second grid 14 are all provided with lattice lines along the X direction, and the X-rays emitted from the X-ray source 11 diffuse in a cone beam shape. In accordance with the irradiation, the cylindrical surface is curved in the Y direction.

Between the radiation source grid 12 and the first grid 13, an interval at which the subject H can be arranged is provided. The distance between the first grid 13 and the second grid 14 is not more than the minimum Talbot distance.

The X-ray image detector 15 is a flat panel detector using a semiconductor circuit, and is disposed behind the second grid 14.

The operation of the X-ray imaging system will be described. X-rays radiated from the X-ray source 11 are partially shielded by the X-ray absorption part of the source grid 12, thereby reducing the effective focal size in the Y direction, and arranging many in the Y direction. A line-shaped X-ray is formed. The phase of each line-shaped X-ray changes when passing through the subject H. As each X-ray passes through the first grid 13, a fringe image reflecting the transmission phase information of the subject H determined from the refractive index of the subject H and the transmitted optical path length is formed. The striped image generated by each line-shaped X-ray is projected onto the second grid 14 and overlaps at the position of the second grid 14.

The stripe image is intensity-modulated by being partially shielded by the second grid 14. In the present embodiment, the fringe scanning method is used to intermittently move the second grid 14 with respect to the first grid 13, and X-rays are irradiated from the X-ray source 11 to the subject H while the X-ray source 11 is stopped. Photographing is performed by the line image detector 15. This intermittent movement is performed in the Y direction at a constant scanning pitch obtained by equally dividing the lattice pitch (for example, divided into five pieces).

An intensity modulation signal representing an intensity change is created from the pixel data of each pixel of the X-ray image detector 15, and the phase shift amount (the phase shift amount with and without the subject H) is calculated. Thus, a phase differential image is obtained. This phase differential image corresponds to the distribution of the X-ray refraction angle in the subject H. By integrating this phase differential image along the X direction, a phase contrast image is obtained.

Since the first and

second grids

13 and 14 differ only in size, the grid structure will be described using the second grid 14 as an example. As shown in FIG. 2, the second grid 14 includes five small grids 17 to 21. These small grids 17 to 21 are all formed in the same manner, and the outer shape is an elongated rectangular shape extending in the X direction, and the lattice lines are also provided along the X direction.

As shown in FIG. 3, each of the small grids 17 to 21 is attached on the support substrate 23. The small grids 17 to 21 are attached to each other at equal intervals and in parallel along the X direction when the support substrate 23 is flat. However, since the support substrate 23 is curved so as to have a cylindrical surface (convex to the X-ray image detector 15 side) when the second grid 14 is manufactured, the surface of the support substrate 23 is completed when the second grid 14 is completed. Although they are equally spaced along each, they will face different angles.

Specifically, when the second grid 14 is viewed from the X-ray source 11 side (Z direction), the small grid 19 disposed in the center of the support substrate 23 is substantially in front of the X-ray source 11 along the X direction. Be placed. Further, the

small grids

18 and 20 are arranged to be inclined at a predetermined angle in the Y direction with respect to the central small grid 19. The

small grids

17 and 21 are arranged to be inclined in the Y direction with respect to the

small grids

18 and 20. As a result, the surfaces of the small grids 17 to 21 face the X-ray focal point 11a of the X-ray source 11 and are arranged substantially perpendicular to the X-ray incident direction. In other words, the second grid 14 approximates a so-called convergence structure, and if each grid part (X absorption part 25 and X-ray transmission part 26 described later) of the small grids 17 to 21 is extended, all of the small grids 17 to 21 are extended. The extended line of the grid structure is substantially converged to the X-ray focal point 11a.

The support substrate 23 is a double structure substrate in which a flexible substrate 26 (first substrate) and a glass substrate 27 (second substrate) are bonded together.

The flexible substrate 26 is flexible and has a low X-ray absorptivity (hereinafter referred to as X-ray transmissive) so as not to affect the X-ray image detected by the X-ray image detector 15. For example, it is formed of polyimide, polyethylene terephthalate (PET), polycarbonate (PC), dry film, parylene, acrylic resin, or the like. However, the flexible substrate 26 has a larger thermal expansion coefficient than the glass substrate 27 or the like instead of being flexible. The thermal expansion coefficient of polyimide is about 54 × 10 ⁻⁶ / ° C. Polyethylene terephthalate is about 60 × 10 ⁻⁶ / ° C., polycarbonate is about 70 × 10 ⁻⁶ / ° C., and acrylic resin is about 70 to 80 × 10 ⁻⁶ / ° C. The thickness of the flexible substrate 26 is about 0.01 to 0.1 mm.

As will be described later, the glass substrate 27 is bonded to the flexible substrate 26 in order to reduce adverse effects due to the large thermal expansion coefficient of the flexible substrate 26, has X-ray transparency, and is flexible. It is formed of glass having a smaller thermal expansion coefficient than that of glass. The glass substrate 27 is made of, for example, Pyrex glass or soda glass. Pyrex glass has a thermal expansion coefficient of about 3.2 × 10 ⁻⁶ / ° C., and soda glass has a thermal expansion coefficient of about 9.0 × 10 ⁻⁶ / ° C. The thickness of the glass substrate 27 is about 0.1 to 0.7 mm.

Here, an example in which the glass substrate 27 is bonded to the flexible substrate 26 to form the support substrate 23 will be described. However, the substrate bonded to the flexible substrate 26 has X-ray transparency and is a flexible substrate. If it is made of a material having a thermal expansion coefficient smaller than 26, it is not necessarily formed of glass. For example, instead of the glass substrate 27, a substrate formed of quartz, silicon, alumina, aluminum, titanium, a titanium alloy, nickel, stainless steel, or the like may be bonded to the flexible substrate 26 to form the support substrate 23.

The glass substrate 26 is a parallel plate at the stage of being bonded to the flexible substrate 26. However, when the small grids 17 to 21 are arranged and the support substrate 23 is curved, the glass substrate 26 cracks between the small grids 17 to 21. And is divided. For this reason, the completed second grid 14 is formed by arranging a sliced piece of the glass substrate 27 and the small grids 17 to 21 on the curved flexible substrate 26, and is curved by the flexible substrate 26. However, the whole is integrally formed. That is, the laminated body of the slice of the glass substrate 27 and the small grids 17 to 21 is integrally held by the flexible substrate 26. As described above, when a substrate made of a metal material is used instead of the glass substrate 26, when the support substrate 23 is curved, the metal substrate spreads between the small grids 17 to 21 and cracks occur. Sometimes it stays together without entering.

As shown in FIG. 4, each of the small grids 17 to 21 has a base substrate 31 and a grid portion 32. The base substrate 31 is a substrate serving as a base when the grid portion 32 is formed. The base substrate 31 is a material having X-ray transparency and a coefficient of thermal expansion smaller than that of the flexible substrate 26 (silicon, glass, carbon, etc.). Formed with.

The grid portion 32 has an X-ray absorbing portion 32a formed of gold, platinum, or the like, and an X-ray transmitting portion 32b formed of a material having X-ray permeability such as silicon. The X-ray absorption part 32 a and the X-ray transmission part 32 b are provided extending in the X direction and provided perpendicular to the surface of the base substrate 31. In addition, the X-ray absorption parts 32 a and the X-ray transmission parts 32 b are alternately provided along the surface of the base substrate 31 without a gap. In the case of the small grid 19, the X-ray absorption parts 32a and the X-ray transmission parts 32b are alternately arranged in the Y direction. The other small grids 17 to 18 and 20 to 21 are inclined according to the curvature of the support substrate 23 as described above, but the structure is the same as that of the small grid 19.

The width W2 and the pitch P2 of the X-ray absorption part 32a are the distance between the source grid 12 and the first grid 13, the distance between the first grid 13 and the second grid 14, and the X-ray absorption part of the first grid 13. It depends on the pitch. For example, the width W2 is about 2 to 20 μm, and the pitch P2 is about 4 to 40 μm. The thickness T2 of the X-ray absorbing portion 25 is preferably as thick as possible in order to obtain high X-ray absorption, but is preferably about 100 μm in consideration of vignetting of X-rays. In the present embodiment, for example, the width W2 is 2.5 μm, the pitch P2 is 5 μm, and the thickness T2 is 100 μm. These values are common to all the small grids 17 to 21.

A seed layer 33 is provided between the base substrate 31 and the grid portion 32. As will be described later, the seed layer 33 is a conductive layer for forming the X-ray absorption portion 32a. The small grids 17 to 21 are attached to the surface of the glass substrate 27 with an adhesive 36, and the flexible substrate 26 and the glass substrate 27 are attached together with an adhesive 37. The

adhesives

36 and 37 may be any one having X-ray transparency and adhesiveness, and resist, parylene, polyimide, or the like may be used. The thickness of the

adhesives

36 and 37 is approximately 10 μm.

As with the second grid 14, the radiation source grid 12 and the first grid 13 are composed of a plurality of small grids and a support substrate in which the small grids are bonded together with an adhesive. Further, the small grids of the source grid 12 and the first grid 13 are provided with a grid portion and a base substrate in the same manner as the second grid 14. The structure of the grid part is the same as that of the grid part 32 of the second grid 14, but the width, pitch, and thickness of the X-ray absorption part and the X-ray transmission part differ depending on the arrangement and the like.

Next, the grid manufacturing method of the present invention will be described using the second grid 14 as an example. In addition, since the manufacturing method of the source grid 12 and the 1st grid 13 is also the same, these description is abbreviate | omitted.

First, the small grids 17 to 21 are manufactured as follows. As shown in FIG. 5, a base substrate 31 is bonded to the lower surface of an X-ray transparent substrate 41 formed of silicon or the like. At this time, a seed layer 33 is formed on the bonding surface between the base substrate 31 and the X-ray transparent substrate 41.

Since the X-ray transmissive substrate 41 will later become the X-ray transmissive portion 32b of the grid portion 32, the X-ray transmissive substrate 41 is formed of the material of the X-ray transmissive portion 32b, and the thickness thereof is determined by the grid portion 32 (X-ray transmissive portion). It is the thickness of the transmission part 32b). The X-ray transparent substrate 41 is particularly preferably made of a material having a thermal expansion coefficient substantially equal to that of the base substrate 31. This is because even if the temperature of the second grid 14 changes during use of the X-ray imaging apparatus 10, the grid portion is caused by the difference in thermal expansion coefficient between the base substrate 31 and the X-ray transmission portion 32 b (X-ray transmission substrate 41). This is to prevent 32 from being damaged. Specifically, for example, the same silicon substrate may be used for the base substrate 31 and the X-ray transparent substrate 41.

The seed layer 33 is formed of, for example, Au or Ni, or a metal film made of a metal film such as Al, Ti, Cr, Cu, Ag, Ta, W, Pb, Pd, or Pt, or an alloy thereof. . The seed layer 33 may be provided on the upper surface of the base substrate 31 and then bonded to the X-ray transmissive substrate 41, or may be provided on the lower surface of the X-ray transmissive substrate 41. It may be provided on both the upper surface of the base substrate 31 and the lower surface of the substrate 41 or the like.

Next, as shown in FIG. 6, an etching mask 42 is formed on the surface of the X-ray transparent substrate 41 by using a photolithography technique. The etching mask 42 has a line-and-space pattern that extends linearly in the X direction and is periodically arranged at a predetermined pitch in the Y direction. The width and pitch of the etching pattern 42 are the width W2 and the pitch P2 of the X-ray transmission part 32b.

When the etching mask 42 is formed, as shown in FIG. 7, by performing dry etching until the seeds layer 33 is exposed using the etching mask 42 as a mask, a plurality of grooves 43 and X-rays are formed in the X-ray transparent substrate 41. A transmission part 32b is formed. Since the groove 32 will later become the X-ray absorbing portion 32a, it is formed with a high aspect ratio of several μm in width and about 100 μm in depth. For this reason, deep etching dry etching such as a Bosch process or a cryo process is used for the dry etching for forming the groove 43 and the X-ray transmission part 32b. Alternatively, the groove may be formed by forming the X-ray transparent substrate 41 using a photosensitive resist instead of silicon and exposing it with synchrotron radiation.

When the groove 43 and the X-ray transmission part 32b are formed, as shown in FIG. 8, the groove 43 is filled with an X-ray absorber such as gold by electrolytic plating. Thereby, the X-ray absorption part 32 a is formed in the groove 43. Specifically, the current terminal is connected to the sheath layer 33, and the X-ray transparent substrate 41 is immersed in the plating solution while being bonded to the base substrate 31. Then, another electrode (anode) is prepared at a position facing the X-ray transmissive substrate 41, and a current flows between the current terminal and the anode. As a result, metal ions in the plating solution are deposited on the patterned X-ray transparent substrate 41, and gold is embedded in the grooves 43.

Thus, when the X-ray absorbing portion 32a is formed, the etching mask 42 is removed by an ashing method or the like. Thereby, small grids 17 to 21 are formed.

In addition, the filling method of the X-ray absorber in the groove 43 is not limited to the above-described electrolytic plating method, and for example, the X-ray absorber may be filled in a paste form or a colloid form. In this case, since the seed layer 33 is unnecessary, the base substrate 31 and the X-ray transmissive substrate 41 may be directly bonded.

As described above, apart from the formation of the small grids 17 to 21, the support substrate 23 is formed as described below. As shown in FIG. 9, first, a glass substrate 27 is bonded to the surface of the flexible substrate 26 using an adhesive 37. At this time, both the flexible substrate 26 and the glass substrate 27 have a parallel plate shape. Accordingly, at this stage, the support substrate 23 has a parallel plate shape.

When the glass substrate 27 is bonded to the flexible substrate 26, as shown in FIG. 10A, linear grooves 51 extending in the X direction at predetermined intervals are formed in the glass substrate 27. The groove 51 serves as a guide for bending, which is a position where the support substrate 23 is naturally bent when the support substrate 23 is bent in a later step.

The groove 51 is formed by partially cutting the glass substrate 27 in the depth direction, and the glass substrate 27 is left at the bottom of the groove 51. For this reason, even if the groove 51 is formed, the flexible substrate 26 is not exposed from the groove 51 and the glass substrate 27 is integrated. The depth of the groove 51 is set to such a depth that the parallel plate shape of the support substrate 23 can be maintained in a later process due to the rigidity of the glass substrate 27. For this reason, even if the flexible substrate 26 expands (shrinks) due to a temperature change or a slight pressure is applied when the small grids 17 to 21 are attached, the glass substrate 27 is unintentionally divided by the grooves 51. The space between the glass substrates 27 remaining between the grooves 51 does not expand or contract, and the support substrate 23 is not bent. As described above, when the support substrate 27 is curved, the groove 51 may be extremely shallow as long as the depth becomes a guide for bending.

Further, as shown in FIG. 10B, the groove 51 has a linear shape extending to the end of the support substrate 23 in the X direction. Each groove 51 is parallel.

The groove 51 is formed by wet etching, sand blasting, laser irradiation or the like. For example, when the grooves 51 are formed by wet etching or the like, a resist pattern that exposes the grooves 51 to be formed is formed on the surface of the glass substrate 27, and the glass substrate 27 is etched using the resist pattern as a mask.

Further, as shown in FIG. 10B, an alignment mark 52 is formed on the surface of the glass substrate 27. The alignment mark 52 is a reference for aligning the small grids 17 to 21 in parallel along the groove 51 so that the intervals between the small grids 17 to 21 are constant. Therefore, the groove 51 and the alignment mark 52 need to be aligned with high accuracy. The alignment mark 52 may be formed at the same time as the groove 51 at the same time as the groove 51, or may be formed at a different process from the formation of the groove 51. When forming the alignment mark 52 in a separate process from the groove 51, the method for forming the groove 51 and the method for forming the alignment mark 52 may be different. Alternatively, the alignment mark 52 may be formed first, and the groove 51 may be formed according to the alignment mark 52.

The position where the alignment mark 52 is provided is arbitrary as long as it can be aligned when the small grids 17 to 21 are arranged. FIG. 10B shows an example in which a plurality of alignment marks 52 are provided at predetermined intervals on the side of the groove 51 and not hidden by the small grids 17 to 21 when the small grids 17 to 21 are arranged. (See also FIG. 11). If the small grids 17 to 21 are parallel to the groove 51 and the intervals between the small grids 17 to 21 can be set constant, the alignment mark 52 is located at a position where part or all of the alignment marks 52 are hidden by the small grids 17 to 21. It may be provided.

As described above, when the grooves 51 and the alignment marks 52 are provided on the surface of the glass substrate 27, the small grids 17 to 21 previously produced have the base substrate 31 facing the glass substrate 27 as shown in FIG. Affixed using an adhesive 36. At this time, the small grids 17 to 21 are arranged on the glass substrate 27 with reference to the alignment mark 52 so that the positions of the small grids 17 to 21 are adjusted in parallel to the groove 51 in the center.

Thus, when the small grids 17 to 21 are affixed on the parallel flat plate-like support substrate 23, the support substrate 23 is curved as shown in FIG. When the support substrate 23 is curved, the stress due to the bending is concentrated in the groove 51, a crack 53 is generated in the groove 51 as a guide, and the glass substrate 27 is divided by the crack 53. Thereby, the support substrate 23 can be freely bent with the crack 53 as a fulcrum. For this reason, the second grid 14 is formed by curving the support substrate 23 so that the directions of the small grids 17 to 21 substantially coincide with the spread of cone-beam X-rays.

As described above, after the small grids 17 to 21 are arranged on the parallel plate-like support substrate 23 in which the flexible substrate 26 and the glass substrate 27 are bonded together, the support substrate 23 is curved to form the second grid 14. The small grids 17 to 21 can be positioned with high accuracy. That is, the relative positional accuracy between the small grids 17 to 21 is good. For example, if the small grids 17 to 21 are to be arranged on a surface curved in a cylindrical shape in advance, the position and orientation of each small grid must be aligned three-dimensionally. On the other hand, when the support substrate 23 is curved after the two-dimensional alignment on the plane and the small grid are arranged on the parallel plate-like support substrate 23 as in the first embodiment described above, A curved grid can be formed while maintaining the alignment accuracy performed in. For this reason, according to the first embodiment described above, alignment between the small grids 17 to 21 is easy.

When the small grids 17 to 21 are arranged directly on the parallel flat plate-like flexible substrate 26 without using the glass substrate 27, an alignment mark 52 for determining the arrangement of the small grids 17 to 21 is provided on the flexible substrate 26. Will be provided. However, since the flexible substrate 26 is more easily expanded and contracted than the glass substrate 27, when the alignment marks 52 are provided on the flexible substrate 26, the interval between the alignment marks 52 is likely to change. For this reason, even if the small grid is aligned according to the alignment mark provided on the flexible substrate 26, it is difficult to perform highly accurate alignment. On the other hand, as in the above-described embodiment, the small grids 17 to 21 are arranged on the support substrate 23 to which the flexible substrate 26 and the glass substrate 27 are bonded, and the alignment for aligning the small grids 17 to 21 is performed. When the mark 52 is provided on the glass substrate 27, the glass substrate 27 has a smaller thermal expansion coefficient than the flexible substrate 26 and is difficult to expand or contract. Therefore, the small grids 17 to 21 are arranged according to the alignment mark 52 provided on the glass substrate 27. Thus, the small grids 17 to 21 can be easily aligned with high accuracy.

Furthermore, when the small grids 17 to 21 are directly arranged on the surface of the flexible substrate 26, the position where the flexible substrate 26 is bent is indefinite between the small grids 17 to 21. Therefore, when the small grids 17 to 21 are directly arranged on the surface of the flexible substrate 26 and the flexible substrate 26 is curved, the bending positions are indeterminate between the small grids 17 to 21 according to the indefinite position between the small grids 17 to 21. An error in the arrangement (angle) of. However, when the support substrate 23 in which the flexible substrate 26 and the glass substrate 27 are bonded together as in the above-described embodiment and the groove 51 serving as a guide for bending the flexible substrate 26 is provided in the glass substrate 27, the flexible substrate 26. Is bent along the groove 51 (crack 53). For this reason, errors in the arrangement (angle) of the small grids 17 to 21 when the support substrate 23 is curved hardly occur, and the grid manufactured as in the above embodiment has high accuracy.

When a large-size grid portion is directly formed on the flexible substrate 26, the width W2 and the pitch P2 of the X-ray transmission portion 32b are likely to change due to the expansion / contraction of the flexible substrate 26, but the small grids 17 to 21 are used. When the grid is formed, the accuracy of the width W2 and the pitch P2 of the X-ray transmission part 32b is almost unaffected by the expansion / contraction of the flexible substrate 26 and is constant. For this reason, the grid formed like the above-mentioned embodiment can exhibit the stable performance.

In the first embodiment described above, the groove 51 and the alignment mark 52 are formed on the glass substrate 27 after the glass substrate 27 is bonded to the flexible substrate 26 to form the support substrate 23. Instead, grooves 51 and alignment marks 52 are formed in advance on the glass substrate 27, and the glass substrate 27 on which the grooves 51 and the alignment marks 52 are already formed is bonded to the flexible substrate 26 to form the support substrate 23. May be. The same applies to the second and third embodiments described later.

[Second Embodiment]
In the first embodiment described above, an example is described in which the groove 51 for specifying the bending position of the flexible substrate 26 is formed in the glass substrate 27. However, the treatment for specifying the bending position in the flexible substrate 26 is further described. May be applied.

For example, as shown in FIG. 13, a low-rigidity portion 61 is formed on the exposed surface of the flexible substrate 26 (the back surface of the support substrate 23) in accordance with the grooves 51 provided in the glass substrate 27. The low-rigidity portion 61 is a portion that is low in rigidity among the flexible substrates 26 and is particularly easy to bend due to stress concentration when the support substrate 23 is bent. The low-rigidity portion 61 is formed, for example, by forming a groove by etching or performing a local heat treatment such as laser irradiation. In addition, the low rigidity portion 61 can be aligned with the groove 51 of the glass substrate 27 by observing the alignment mark 52 provided on the glass substrate 27 as an index.

As described above, if the flexible substrate 26 is also provided with the low-rigidity portion 61 in accordance with the groove 51 of the glass substrate 27, the groove 51 and the low-rigidity portion 61 can be more reliably formed when the support substrate 23 is curved. The support substrate 23 is curved along the surface. For this reason, the placement accuracy of the small grids 17 to 21 in the grid after bending the support substrate 23 becomes higher.

In FIG. 13, the low rigidity portion 61 is formed on the exposed surface of the flexible substrate 26 (the back surface of the support substrate 23). However, as shown in FIG. 14, the low rigidity portion 61 is bonded to the glass substrate 27. You may provide in the surface side. In this case, it is preferable to form the low rigidity portion 61 by local heat treatment by laser irradiation.

In the second embodiment described above, the low rigidity portion 61 is provided in the flexible substrate 26 in accordance with the groove 51 (and the alignment mark 52) provided in the glass substrate 27. However, the low rigidity portion 61 is provided in the flexible substrate 26 in advance. 61 may be provided.

However, when the low-rigidity portion 61 is provided in the flexible substrate 26 in advance, if the low-rigidity portion 61 is formed with a width equal to or less than the groove 51 provided in the glass substrate 27, the groove is caused by expansion / contraction of the flexible substrate 26 as described above. It is difficult to align 51 and the low rigidity portion 61 with high accuracy. Further, if the positions of the groove 51 and the low-rigidity portion 61 are deviated, the support substrate 23 cannot be a guide for bending. For this reason, when the low-rigidity portion 61 is provided in advance on the flexible substrate 26 as described above, even if the position of the low-rigidity portion 61 is displaced due to the expansion / contraction of the flexible substrate 26, the low-rigidity portion 61 is directly below the groove 51. As shown, it is preferable to provide the low rigidity portion 61 wider than the groove 51.

In the second embodiment described above, the low-rigidity portion 61 is partially provided in the thickness direction of the flexible substrate 26, but the entire thickness direction corresponding to the groove 51 is the low-rigidity portion 61. good. However, processing is easier when the low-rigidity portion 61 is provided near the surface of the flexible substrate 26.

[Third Embodiment]
In the first and second embodiments described above, the groove 51 provided in the glass substrate 27 is linearly provided to the end of the support substrate 23. In addition to this, the glass substrate 27 of the first and second embodiments is not provided. As shown in FIG. 15, the groove 51 may be formed in a perforated shape by a groove 62 in which the glass substrate 27 is cut and a joint portion 63 in which the glass substrate 27 is not cut.

In this case, as in the Y-direction cross section (XVI cross section) including the groove 62 shown in FIG. 16, the groove 62 may be provided so as to penetrate the glass substrate 27 and reach the flexible substrate 26. This is because the glass substrate 27 is not cut by the coupling portion 63 as in the Y-direction cross section (XVII cross section) including the coupling portion 63 shown in FIG. 17, so that a groove 62 is provided so as to penetrate the glass substrate 27. In addition, the glass substrate 27 can maintain an integral shape by the coupling portion 63. As a result, the support substrate 23 can ensure a certain degree of rigidity to such an extent that the flexible substrate 26 is not bent unintentionally in a later step.

In addition, when the groove | channel formed in the glass substrate 27 is provided in the perforated form by the groove | channel 62 and the coupling | bond part 63, the length xa along the X direction of the groove | channel 62 and the length along the X direction of the coupling | bond part 63 are shown. The ratio of xb is preferably about 7: 3 (= xa: xb). This depends on the thickness of the glass substrate 27, the depth of the groove 62, the thickness of the coupling portion 63, etc., but the glass substrate 27 has a thickness of about 0.1 to 0.7 mm as described above. If the flexible substrate 26 is cut out until the flexible substrate 26 is exposed, and the coupling portion 63 is not cut at all, if the groove 62 is longer than the above-described ratio, the glass substrate 27 is easily broken along the groove 62. On the other hand, if the coupling portion 63 is long, the coupling portion 63 is difficult to break along the groove 62 when the support substrate 23 is curved after the small grids 17 to 21 are arranged, and the groove 62 and the coupling portion 63 are bent guides. The role may not be fulfilled enough.

In the third embodiment described above, the groove 62 is cut until the flexible substrate 26 is exposed, and the coupling portion 63 is not cut at all. However, the glass substrate 27 is partially left at the bottom of the groove 62. A part of the glass substrate 27 may be cut. Furthermore, a part of the surface of the glass substrate 27 corresponding to the coupling portion 63 may be cut. That is, when the support substrate 23 is curved, the groove 62 is more easily cracked than the coupling portion 63, has a certain rigidity so that there is no problem in a later process, and the groove 62 and the coupling portion are curved when the support substrate 23 is curved. As long as the line formed by 63 can be appropriately bent by the flexible substrate 26, the depth of the groove 62 and the thickness of the glass substrate 27 at the coupling portion 63 are arbitrary.

Further, in the above-described third embodiment, when the positions of the grooves 62 and the coupling portions 63 are compared in the Y direction in the guideline by the four grooves 62 and the coupling portions 63 formed on the support substrate 23, all the lines are displayed. In this example, the positions of the groove 62 and the coupling portion 63 are aligned, but the positions of the groove 62 and the coupling portion 63 may be shifted on each line. For example, as shown in FIG. 18, the arrangement period of the groove 62 and the coupling portion 63 is shifted by a half cycle between adjacent lines, and the coupling portion 63 on the adjacent line is formed at a position corresponding to the groove 62 on a certain line. You may do it.

In the third embodiment described above, a groove (and a connecting portion) is used in the glass substrate 27 as a guide for the bending position of the flexible substrate 26. However, in addition to the groove, a low-rigidity portion 61 is provided in the flexible substrate 26. Also good. In this case, as shown in FIG. 19, a linear low-rigidity portion 61 is provided at a position corresponding to the groove 62 and the coupling portion 63 regardless of the groove 62 and the coupling portion 63 of the glass substrate 27.

Further, as shown in FIG. 20, the flexible substrate 26 may be provided with a low-rigidity portion 66 in a perforated shape only in a portion corresponding to the groove 62 of the glass substrate 27. In this case, the bending promotion effect of the support substrate 23 by the groove 62 directly above and the bending promotion effect by the low-rigidity portion 66 are synergistic. For this reason, when the support substrate 23 is curved, stress for bending is transmitted to the coupling portion 63 along the groove 62 of the glass substrate 27 and the low-rigidity portion 66 of the flexible substrate 26 that are aligned on one straight line. It becomes easy, and even if the groove | channel 62 grade | etc., Is perforated, the bending line of the flexible substrate 26 can be made into a linear form more reliably.

As shown in FIG. 21, by providing a low rigidity portion 67 at a position corresponding to the coupling portion 63 without providing a low rigidity portion below the groove 62 of the glass substrate 27, the low rigidity portion is provided in a perforated shape. Also good. In this case, the low rigidity processing of the flexible substrate 26 can be reduced, and at the same time, the bending direction of the flexible substrate 26 can be made more surely linear.

Further, as shown in FIG. 22, the low-rigidity portion 68 may be provided with a half-cycle shift with respect to the cycle of the groove 62 and the coupling portion 63 of the glass substrate 27.

In the first to third embodiments described above, the radiation source grid 12, the first grid 13, and the second grid 14 that are curved in a cylindrical shape in the Y direction are described as an example. 14 may be spherically curved. As described above, when the grids 12 to 14 are curved into a spherical shape, as shown in FIG. 23, the small grids 17 to 17 that are extended in the X direction and arranged in the Y direction in the first to third embodiments described above. 21 may be further divided in the X direction, and the grids 12 to 14 may be curved in the X direction. In this case, the groove provided in the glass substrate 27 so as to serve as a guide for bending the flexible substrate 26 may be provided along the Y direction as in the first to third embodiments.

In the first to third embodiments described above, when the small grids 17 to 21 are arranged on the support substrate 23, the base substrate 31 is attached to the surface of the glass substrate 27 so that the grid portion 32 is exposed. However, as shown in FIG. 24, the grid portion 32 may be attached to the surface of the glass substrate 27 so that the base substrate 31 is exposed.

In the first to third embodiments described above, the grid is manufactured by bending the support substrate 23. However, as described below, the support substrate 23 can be easily maintained in a curved shape. preferable.

For example, as shown in FIG. 25, the second grid 14 formed by curving the support substrate 23 is fixed by adhering to the same curved base 71 with an adhesive or the like. This makes it easier to maintain the curved shape of the support substrate 23 more reliably. In addition, when the support substrate 23 is curved, the second grid 14 may be attached to the pedestal 71 and the curved shape may be reliably fixed simultaneously by bending the support substrate 23 along the pedestal 71. The base 71 may be made of any material as long as it is X-ray transparent, but is preferably formed of a material having a coefficient of thermal expansion smaller than that of the flexible substrate 26 at least.

Further, as shown in FIG. 26, after the support substrate 23 is curved to form the second grid 14, a filler 72 is put into a gap generated between the small grids 17 to 21 as the support substrate 23 is curved, It may solidify. The filler 72 may be made of an arbitrary material such as an epoxy adhesive, a silver paste, or a gold paste. However, it is preferable to use a filler made of an X-ray absorbing material such as silver paste or gold paste. When an X-ray absorbing filler is used, noise components such as artifacts caused by X-rays transmitted through the small grids 17 to 21 can be reduced.

Furthermore, as shown in FIG. 27, a shape memory substrate 73 may be used instead of the flexible substrate 26. When the shape memory substrate 73 is used, the shape to be memorized is the curved shape of the support substrate 23, and is formed in a parallel plate shape when the second grid 14 is manufactured. Then, as in the first to third embodiments described above, after the small grids 17 to 21 are arranged, a process (for example, a heat treatment) for returning the shape memory substrate 73 to the memory shape is performed, whereby the support substrate 23 is changed. Curve to a predetermined shape. When the shape memory substrate 73 is used in this manner, an appropriate curved state of the second grid 14 can be easily maintained by the shape memory action of the shape memory substrate 73. The shape memory substrate 73 can be formed of a shape memory polymer or a shape memory alloy. The shape memory polymer is, for example, polynorbornene, trans polyisoprene, polyurethane or the like. The shape memory alloy is, for example, NiTi, NiTiCo, NiTiCu or the like.

Similarly, as shown in FIG. 28, instead of the flexible substrate 26, a composite substrate 76 in which a shape memory layer 74 made of a fiber-shaped shape memory polymer or shape memory alloy is knitted into a flexible resin (polyimide or the like) 75 is used. You may use for. The composite substrate 76 also exhibits substantially the same function and effect as the shape memory substrate 73.

As described above, when the shape memory substrate 73 or the composite substrate 76 is used, the small grids 17 to 21 may be directly attached on the shape memory substrate 73 or the composite substrate 76 without attaching the glass substrate 27. good. This is because, in the case of the shape memory substrate 73 and the composite substrate 76, the thermal expansion coefficient is not as large as that of the flexible substrate 26.

In the first to third embodiments described above, the second grid 14 is formed using the five small grids 17 to 21, but the number of small grids used is not limited to five. At least two small grids are required to arrange the small grid in a cylindrical surface (or spherical shape), but in order to be closer to the cylindrical surface (spherical shape), the number of small grids is as large as possible. Better.

In the first to third embodiments described above, the source grid 12, the first grid 13, and the second grid 14 are all absorption grids, and the grid portion 32 includes the X-ray absorption portion 32a and the X-ray transmission portion 32b. And are formed alternately. In addition, a so-called phase type grid may be used for the first grid 13. The phase-type grid is a grid in which two types of members having X-ray transparency are alternately arranged perpendicular to the surface. For example, in the grid portion 32 of the absorption-type grid, the X-ray absorption portion 32a is made of air. It is a layer (a state in which the X-ray absorber is not buried). The present invention is also suitable when using a phase-type small grid.

In the first to third embodiments described above, the radiation source grid 12, the first grid 13, and the second grid 14 are all curved in a cylindrical shape, but at least the first grid 13 or the second grid 14 One side should just be curving in the shape of a cylindrical surface (or spherical shape).

In each of the above embodiments, the first and second grids are configured to linearly (geometrically optically) project the X-rays that have passed through the X-ray transmission part, but International Publication WO 2004/058070. As described in Japanese Patent Publication (U.S. Pat. No. 7,180,796) and the like, the Talbot interference effect may be generated by diffracting the X-rays at the X-ray transmission part. In this case, it is necessary to set the distance between the first and second grids to the Talbot distance. In this case, the first grid can be a phase grid instead of the absorption grid. The phase type grid forms a fringe image (self-image) generated by the Talbot interference effect at the position of the second grid.

In the above embodiment, the subject H is disposed between the X-ray source and the first grid, but the subject H may be disposed between the first grid and the second grid. In this case as well, a phase contrast image is similarly generated. In the above embodiment, the source grid 12 is provided, but the source grid 12 may be omitted.

Further, in each of the above embodiments, a striped one-dimensional grid having X-ray absorbing portions and X-ray transmitting portions that are extended in one direction and alternately arranged along the arrangement direction orthogonal to the extending direction will be described as an example. However, the present invention can also be applied to a two-dimensional grid in which an X-ray absorption part and an X-ray transmission part are arranged in two orthogonal directions. In this case, the phase contrast image may be generated by a fringe scanning method in which a plurality of shootings are performed, or the phase contrast image may be generated by a single shooting. In order to generate a phase contrast image by one imaging, for example, a checkered phase type grid is used for the first grid and a mesh pattern amplitude type is used for the second grid, as described in WO2010 / 050484. Take a picture using the grid. This single photographed image is subjected to Fourier transform, and the primary spectra in the vertical and horizontal directions are respectively extracted. By performing inverse Fourier transform on these primary spectra, a phase differential image in two directions is obtained.

Note that according to the present invention described in the first to third embodiments, it is possible to provide a high-quality phase imaging grid particularly considering temperature change (and thermal expansion due to temperature change). For example, at the time of photographing, the degree of curvature of the grid may slightly change when an environmental temperature change occurs. At this time, if the relative arrangement accuracy of the small grids 17 to 21 is poor, the contrast of the fringe image may deteriorate depending on the relative arrangement variation between the small grids 17 to 21. However, according to the present invention, since the relative arrangement of the small grids 17 to 21 is accurate, deterioration of the contrast of the fringe image can be suppressed even if the environmental temperature changes. Further, when the grid is manufactured, the adhesive may be heated to harden the adhesive, and the flexible substrate 26 may be thermally deformed by the heat. According to the present invention, the above-described heat deformation is performed. Even if there is, the small grids 17 to 21 can be arranged with relatively high accuracy.

The above embodiments may be combined with each other within a consistent range. The present invention is applicable not only to a radiographic imaging system for medical diagnosis but also to other radiographic systems for industrial use and nondestructive inspection. The grid of the present invention can also be applied to a scattered radiation removal grid that removes scattered radiation in X-ray imaging. Furthermore, the present invention can also be applied to a radiographic imaging system that uses gamma rays or the like in addition to X-rays.

Claims

A plurality of small grids having a flat base substrate and a grid portion that is formed on the base substrate and that partially transmits the radiation irradiated from the focal point of the radiation source and generates a fringe image;
A flexible first substrate and a second substrate having a thermal expansion coefficient smaller than that of the first substrate are bonded together, and further on the second substrate according to an alignment mark provided on the second substrate. A support substrate curved so that the grid portion of each small grid faces the focal point of the radiation source after arranging the small grids in a predetermined arrangement
A grid for radiographic imaging, comprising:
The second substrate is a glass substrate, and is divided according to the arrangement of the small grids along with the curvature of the support substrate, and the slice of the second substrate after the division and the laminated body of the small grids are curved. The grid for radiographic imaging according to claim 1, wherein the grid is integrally held by a first substrate.
The radiographic imaging grid according to claim 1, wherein a groove for specifying a bending position of the support substrate is provided on a surface of the second substrate.
The radiographic imaging grid according to claim 3, wherein the groove is provided in a perforation along the surface of the second substrate.
The radiographic imaging grid according to claim 1, wherein the groove is formed by partially cutting the second substrate in a thickness direction.
The radiographic imaging grid according to claim 4, wherein the groove is formed by cutting the second substrate in the thickness direction.
4. The radiographic imaging according to claim 3, wherein the first substrate has a low-rigidity portion with reduced rigidity on a straight line corresponding to the groove formed in the second substrate. grid.
The radiographic imaging grid according to claim 1, wherein the first substrate is a substrate using a shape memory material.
The radiographic imaging grid according to claim 1, wherein the small grid is an absorption grid having the grid portion formed by alternately arranging a radiation absorbing portion and a radiation transmitting portion.
2. The radiographic imaging according to claim 1, wherein the small grid is a phase type grid having the grid portion formed by alternately arranging two kinds of members having radiolucency. grid.
A small grid that forms a plurality of small grids having a flat base substrate and a grid portion that is formed on the base substrate and that partially transmits the radiation irradiated from the focal point of the radiation source and generates a fringe image. Forming process;
A support substrate forming step of forming a support substrate by bonding a flexible parallel plate-shaped first substrate and a parallel plate-shaped second substrate having a thermal expansion coefficient smaller than that of the first substrate;
In accordance with the alignment mark provided on the second substrate, a small grid attaching step of attaching the small grid on the second substrate in a predetermined arrangement;
A step of bending the support substrate to which the small grid is attached so that the grid portion of each of the small grids faces the focal point of the radiation source. Method.
12. The method for manufacturing a grid for radiographic imaging according to claim 11, further comprising a groove forming step of providing a groove for specifying a bent position of the support substrate on the second substrate.
The method for manufacturing a grid for radiographic imaging according to claim 12, further comprising a low-rigidity processing step of forming a low-rigidity portion having low rigidity on the first substrate.
A first grid for transmitting a radiation emitted from a radiation source to generate a fringe image; a second grid for applying intensity modulation to the fringe image; and a radiation image for detecting a fringe image intensity-modulated by the second grid. And a radiographic imaging system that generates a phase contrast image from a fringe image detected by the radiological image detector, wherein at least one of the first grid or the second grid is:
A plurality of small grids each having a flat base substrate and a grid portion that is formed on the base substrate and that partially transmits the radiation irradiated from the focal point of the radiation source to generate a fringe image; and flexibility And a predetermined arrangement on the second substrate according to an alignment mark provided on the second substrate, and a second substrate having a thermal expansion coefficient smaller than that of the first substrate. And a support substrate that is curved so that the grid portion of each of the small grids faces the focal point of the radiation source after the small grids are arranged in the radiographic imaging system.
And a radiation source grid disposed between the radiation source and the first grid and configured to selectively shield the radiation irradiated from the radiation source to form radiation on a plurality of lines. Radiation imaging system.
The radiation source grid includes a plurality of small base plates having a flat base substrate and a grid portion that is formed on the base substrate and generates a fringe image by partially transmitting the radiation irradiated from the focal point of the radiation source. A grid, a flexible first substrate, and a second substrate having a smaller coefficient of thermal expansion than the first substrate are bonded together, and the second substrate is formed according to an alignment mark provided on the second substrate. And a support substrate that is curved so that the grid portion of each of the small grids faces a focal point of a radiation source after the small grids are arranged in a predetermined arrangement on the substrate. 15. A radiographic imaging system according to item 14.