JP6958716B2 - X-ray phase difference imaging system - Google Patents

Description

The present invention relates to an X-ray phase difference imaging system, and more particularly to an X-ray phase difference imaging system that generates a phase contrast image including a dark field image by a Talbot interferometer.

Conventionally, an X-ray phase difference imaging system that generates a phase contrast image including a dark field image by using a Talbot interferometer is known. Such an X-ray phase difference imaging system is disclosed in, for example, Japanese Patent No. 6173457 and International Publication No. 2012/128335.

The X-ray phase difference imaging system disclosed in Japanese Patent No. 6173457 includes an X-ray source, a multi-slit, a phase grid, an absorption grid, a detector, and a stepping arrangement for stepping the phase grid. .. The X-ray phase difference imaging system disclosed in Japanese Patent No. 6173457 can generate a phase contrast image including a dark field image by step-moving the phase grid for imaging. The "dark field image" is a Visibility image obtained by a change in Visibility based on small-angle scattering of an object. The dark field image is also called a small-angle scattered image. "Visibility" means sharpness. Further, the phase contrast image includes an absorption image and a phase differential image in addition to the dark field image. The "absorption image" is an image imaged based on the attenuation of X-rays generated when X-rays pass through a subject. The "phase differential image" is an image imaged based on the phase shift of the X-rays generated when the X-rays pass through the subject.

Here, when an image of a dark field image is taken, if the diffusion of X-rays due to the internal structure of the subject is directional, the internal structure is an image depending on the relationship between the orientation of the grid and the orientation (diffusion direction) of the subject with respect to the grid. It may not be converted. Specifically, among the diffusion directions of X-rays due to the internal structure of the subject, the X-rays diffused in the direction orthogonal to the direction of the grid are emphasized, so that the internal structure is imaged. However, since X-rays diffused in the direction along the direction of the grid are hardly imaged (there is no sensitivity), there is an inconvenience that it may be difficult to image the internal structure depending on the orientation of the subject with respect to the grid.

Therefore, International Publication No. 2012/128335 discloses an X-ray phase difference imaging system that changes the orientation of a subject with respect to a grid and images the image by rotating the grid by a grid rotating unit. Specifically, the X-ray phase difference imaging system disclosed in International Publication No. 2012/128335 includes a multi-slit rotating unit that rotates a multi-slit and a grid rotating unit that rotates the first and second grids. It has. It is configured to change the orientation of the subject with respect to the grid by rotating a plurality of grids by the multi-slit rotating portion and the grid rotating portion.

Japanese Patent No. 6173457 International Publication No. 2012/128335

However, in the X-ray phase difference imaging system disclosed in International Publication No. 2012/128335, since a plurality of grids are rotated by both the multi-slit rotating portion and the grid rotating portion, the grids are rotated. The relative position of each grid after that may change. In the Talbot interferometer, when the relative position between a plurality of lattices changes, unintended moire occurs, which causes an inconvenience that an artifact occurs in the generated phase contrast image. Therefore, in order to suppress the occurrence of unintended moire, there is a problem that the positions of a plurality of grids must be adjusted each time the orientation of the subject with respect to the grid is changed.

The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to deal with a grid without adjusting the positions of a plurality of grids each time the orientation of the subject with respect to the grid is changed. It is an object of the present invention to provide an X-ray phase difference imaging system capable of changing the orientation of a subject.

In order to achieve the above object, the X-ray phase difference imaging system in one aspect of the present invention includes an X-ray source, a detector for detecting X-rays emitted from the X-ray source, and an X-ray source and a detector. A plurality of lattices are arranged between the above and include a first lattice in which X-rays are emitted from an X-ray source and a second lattice in which X-rays are emitted from the first lattice, and are detected by a detector. An image processing unit that generates a phase contrast image based on a signal and a predetermined part of the subject are rotated around the X-ray optical axis direction along an arc-shaped trajectory when the subject is imaged. Provided with a subject rotation mechanism capable of directing a plurality of lattices in a direction in which the lattices extend and in a direction intersecting the direction in which the lattices of the plurality of lattices extend in a plane orthogonal to the X-ray optical axis direction.

In the X-ray phase difference imaging system according to one aspect of the present invention, as described above, by rotating the subject along an arcuate orbit, a predetermined portion of the subject is extended in a direction in which a plurality of grids extend. Also provided is a subject rotation mechanism capable of directing a plurality of lattices in a direction orthogonal to the direction of the optical axis of the X-ray and in a direction intersecting the direction in which the lattices of the plurality of lattices extend. Thereby, by rotating the subject, the orientation of the subject with respect to the grid can be changed without rotating the grid. As a result, since the grid is not rotated, the orientation of the subject with respect to the grid can be changed without adjusting the positions of the plurality of grids each time the orientation of the subject with respect to the grid is changed. Further, for example, by a mechanism that covers the periphery of the subject over one circumference, the rotation range can be reduced as compared with the case where the subject is rotated along the circumferential orbit. As a result, it is possible to prevent the subject rotation mechanism from becoming large.

In this case, preferably, the subject rotation mechanism includes a subject holding portion for holding the subject, an arc-shaped guide rail for holding the subject holding portion in a movable manner, and changing the direction of the subject holding portion along the guide rail. It is provided with a rotation drive unit that moves the subject holding unit in an arc shape. With this configuration, the subject can be easily rotated in an arc shape by moving the subject holding portion along the arc-shaped guide rail by the rotation drive unit.

In a configuration in which the subject rotation mechanism includes a subject holding portion, an arc-shaped guide rail, and a rotation driving portion, the rotation range of the subject holding portion preferably has a semicircle or an arc shape smaller than a semicircle. From one end side to the other end side of the guide rail, the rotation drive unit is configured to move the subject holding unit that holds the subject on the inner peripheral surface side of the arc-shaped guide rail. With this configuration, if the guide rail has a semicircular arc shape, the subject can be rotated 180 degrees. As a result, even if the direction in which the subject diffuses X-rays is unknown, the subject can be arranged in a direction in which the diffusion of X-rays can be detected with high sensitivity. Further, when the guide rail has an arc shape smaller than a semicircle, for example, even if the part of the subject on the side not held by the subject holding portion protrudes from the curvature circle of the guide rail, the subject holding portion is guided by the guide rail. It is possible to prevent the portion of the subject that is not held by the subject holding portion from coming into contact with the end portion on the opposite side of the guide rail when it is rotated to the end portion of the guide rail. As a result, the orientation of the subject with respect to the grid can be easily changed even when the portion of the subject on the side not held by the subject holding portion protrudes from the circle of curvature of the guide rail.

In a configuration in which the subject rotation mechanism includes a subject holding portion, an arc-shaped guide rail, and a rotation driving portion, the rotation range of the subject holding portion is preferably a guide having an arc shape with a central angle of at least 90 degrees. From one end side to the other end side of the rail. Here, when the scattering direction of X-rays by the subject and the extending direction of the grid are orthogonal to each other, the contrast of the obtained dark field image becomes clear. Of the microstructures inside the subject, even if the microstructures are not oriented in the direction orthogonal to the extending direction of the grid, if the orientation of the subject with respect to the grid can be rotated by at least 90 degrees, the microstructures inside the subject can be gridded. It is possible to point in a direction orthogonal to the extending direction of. Therefore, with the above configuration, the orientation of the subject can be changed by 90 degrees by moving the subject holding portion from one end side to the other end side of the guide rail, and the fine structure inside the subject can be changed to a grid. It can be oriented in a direction orthogonal to the extending direction. As a result, the subject can be arranged in a direction in which the scattering direction of the X-rays by the subject and the extending direction of the grid are orthogonal to each other, so that a dark field image having a clear contrast can be obtained.

In the configuration in which the subject rotation mechanism includes a subject holding portion, an arc-shaped guide rail, and a rotation driving portion, the rotation driving portion is preferably configured to move along the guide rail together with the subject holding portion. ing. With this configuration, the subject holding unit can be moved by moving the rotation driving unit. Therefore, when compared with the configuration in which the rotation driving unit does not move together with the subject holding unit, the rotation driving unit It is possible to simplify the configuration of the mechanism for transmitting power to the subject holding portion. As a result, it is possible to simplify the configuration of the mechanism for transmitting power to the subject holding unit, so that the configuration of the device can be simplified.

In this case, preferably, a first engaging member rotatably provided on the rotation driving unit and a second engaging member provided on the guide rail and engaging with the first engaging member are further included and rotated. The dynamic drive unit is configured to move the subject holding unit in an arc shape along the guide rail by rotating the first engaging member to relatively move the first engaging member and the second engaging member. Has been done. With this configuration, by rotating the first engaging member, the subject holding portion can be moved along the second engaging member provided on the arc-shaped guide rail. As a result, the device configuration can be simplified as compared with the configuration in which the subject holding portion is moved by a ball screw mechanism or the like.

In a configuration in which the subject rotation mechanism includes a subject holding portion, an arcuate guide rail, and a rotation drive portion, the subject rotation mechanism preferably has a position of the center of curvature of the guide rail on the optical axis of X-rays. It is arranged so as to be. With this configuration, the position of the center of curvature of the guide rail is on the optical axis of the X-ray, so even if the subject is rotated to capture a plurality of phase-contrast images, the subject reflected in each phase-contrast image. Can be prevented from translating between the phase contrast images. As a result, even when the phase-contrast images are combined, the alignment can be performed by rotating the subject, so that the phase-contrast images can be easily combined.

In a configuration in which the subject rotation mechanism includes a subject holding portion, an arc-shaped guide rail, and a rotation driving portion, it is preferable to use an imaging system and subject rotation composed of an X-ray source, a detector, and a plurality of lattices. The mechanism is further provided with a three-dimensional imaging rotation mechanism that rotates the mechanism relative to the vertical axis in a plane orthogonal to the optical axis direction of the X-ray, and the image processing unit has a plurality of phases imaged at a plurality of rotation angles. It is configured to generate a three-dimensional phase contrast image from the contrast image. With this configuration, it is possible to generate a three-dimensional phase contrast image without adjusting the positions of the plurality of grids when the orientation of the subject with respect to the grid is changed.

In this case, preferably, the subject holding portion is configured to hold the subject at a position closer to the center of curvature of the guide rail than the line segment connecting both ends of the guide rail. With this configuration, it is possible to prevent both ends of the guide rail from entering the imaging range. As a result, even when the image pickup system and the subject are imaged while being relatively rotated, it is possible to prevent both ends of the guide rail from being reflected in the phase contrast image. The imaging range is a range of the detector that is irradiated with X-rays and is a range that is captured in the phase contrast image.

In the configuration including the three-dimensional image pickup rotation mechanism, preferably, the guide rail has a central angle of the guide rail substantially on both sides around the optical axis direction of the X-ray with reference to the axial direction of the relative rotation by the three-dimensional image pickup rotation mechanism. It is formed so that the angles are equal. With this configuration, the center of the guide rail and the axial direction of relative rotation can be made to substantially coincide with each other. As a result, the guide rails are formed at substantially equal angles on both sides based on the axial reference of the relative rotation, so that the angle of the central angle of the guide rails is increased and both ends of the guide rails are suppressed from entering the imaging range. can do.

The X-ray phase difference imaging system in the above one aspect preferably further includes a subject position adjustment mechanism that holds the subject rotation mechanism and adjusts the position of the subject. With this configuration, the position of the subject can be adjusted while the subject is rotated by the subject rotation mechanism. As a result, it is possible to adjust the position of the subject while maintaining the rotation angle of the subject. However, the imaging range can be changed while maintaining the rotation angle of the subject.

In the X-ray phase difference imaging system in the above one aspect, preferably, a grid position adjusting mechanism for adjusting the relative position between the grids of a plurality of grids is further provided. With this configuration, even if the relative positions of the lattices change due to heat, for example, the relative positions of the plurality of lattices among the lattices can be adjusted. As a result, it is possible to suppress the occurrence of unintended moire due to the change in the relative position between the grids of the plurality of grids, and it is possible to suppress the deterioration of the image quality of the phase contrast image.

In the X-ray phase difference imaging system in one aspect, preferably, the plurality of grids further includes a third grid arranged between the X-ray source and the first grid. With this configuration, the coherence of X-rays emitted from the X-ray source by the third lattice can be enhanced. As a result, it is possible to form a self-image of the first lattice without depending on the focal size of the X-ray source, so that the degree of freedom in selecting the X-ray source can be improved.

According to the present invention, as described above, an X-ray phase difference imaging system capable of changing the orientation of a subject with respect to a grid without adjusting the positions of a plurality of grids each time the orientation of the subject with respect to the grid is changed. Can be provided.

It is a figure which shows the whole structure of the X-ray phase difference imaging system by 1st Embodiment. It is a schematic diagram for demonstrating the arrangement of the X-ray source of the X-ray phase difference imaging system by 1st Embodiment, a plurality of lattices, and a detector. It is a perspective view of the subject rotation mechanism included in the X-ray phase difference imaging system according to 1st Embodiment. It is a schematic diagram which looked at the subject rotation mechanism of the X-ray phase difference imaging system by 1st Embodiment from the Z direction. It is a schematic diagram which enlarged the rotation drive part of the subject rotation mechanism in FIG. It is a schematic diagram which looked at the subject rotation mechanism of the X-ray phase difference imaging system by 1st Embodiment from the X direction. It is a schematic diagram for demonstrating the structure of the grid position adjustment mechanism and the subject position adjustment mechanism by 1st Embodiment. It is sectional drawing which looked at the subject from the Z direction. It is sectional drawing which looked at the subject from the X direction. It is sectional drawing which looked at the subject from the Y direction. It is a schematic diagram of the 1st dark field image imaged by the X-ray phase difference imaging system according to 1st Embodiment. It is a schematic diagram of the 2nd dark field image imaged by the X-ray phase difference imaging system according to 1st Embodiment. It is a schematic diagram when the subject rotation mechanism by 1st Embodiment tilts a subject by −45 degrees. It is a schematic diagram when the subject rotation mechanism by 1st Embodiment tilts a subject 45 degrees. It is a figure which shows the whole structure of the X-ray phase difference imaging system by 2nd Embodiment. It is a schematic diagram of the 3D dark field image generated by the X-ray phase difference imaging system according to 2nd Embodiment. It is a figure which shows the whole structure of the X-ray phase difference imaging system by 1st modification of 1st Embodiment. It is a figure which shows the whole structure of the X-ray phase difference imaging system by the 2nd modification of 1st Embodiment.

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

[First Embodiment]
The configuration of the X-ray phase difference imaging system 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 14.

(Configuration of X-ray phase difference imaging system)
First, the configuration of the X-ray phase difference imaging system 100 according to the first embodiment will be described with reference to FIGS. 1 to 7.

As shown in FIG. 1, the X-ray phase difference imaging system 100 uses the attenuation of X-rays, the change of phase, and the diffusion of X-rays when the subject T is irradiated with X-rays to image the inside of the subject T. It is a system that becomes. Further, the X-ray phase difference imaging system 100 is a system that images the inside of the subject T by utilizing the Talbot effect. In the first embodiment, an example of imaging the inside of the subject T by utilizing the diffusion of X-rays that have passed through the subject T will be described. The X-ray phase difference imaging system 100 can be used for imaging the inside of the subject T as an object, for example, in non-destructive inspection applications.

As shown in FIG. 1, the X-ray phase difference imaging system 100 includes an X-ray source 1, a third grid 2, a first grid 3, a second grid 4, a detector 5, a control device 6, and the like. It includes a subject rotation mechanism 7, a grid position adjusting mechanism 8, and a subject position adjusting mechanism 9. In the present specification, the vertical direction is the Y direction, the vertically upward direction is the Y1 direction, and the vertical downward direction is the Y2 direction. Further, the two orthogonal directions in the horizontal plane orthogonal to the Y direction are defined as the X direction and the Z direction, respectively. Of the X directions, one is the X1 direction and the other is the X2 direction. Further, of the Z directions, one is the Z1 direction and the other is the Z2 direction. In the example shown in FIG. 1, the X-ray source 1, a plurality of grids, and the detector 5 are arranged side by side in the Z direction. The Z direction is an example of the "optical axis direction of X-rays" in the claims.

The X-ray source 1 is configured to generate X-rays by applying a high voltage and to irradiate the generated X-rays in the Z1 direction.

FIG. 2 is a schematic view of the X-ray phase difference imaging system 100 as viewed from the Y direction. In FIG. 2, for convenience, the subject rotation mechanism 7, the subject position adjustment mechanism 9, and the grid position adjustment mechanism 8 are not shown.

As shown in FIG. 2, the third lattice 2 has a plurality of X-ray transmitting portions 2a and X-ray shielding portions 2b. The X-ray transmitting portion 2a and the X-ray shielding portion 2b are formed so as to extend linearly. Also, X-ray transmitting portion 2a and the X-ray shielding portion 2b is arranged at a predetermined period (pitch) d ₃ in the direction perpendicular to the direction X-ray transmitting portion 2a and the X-ray shielding portion 2b extends.

The third lattice 2 is arranged between the X-ray source 1 and the first lattice 3, and is a space for X-rays by shielding a part of the X-rays emitted from the X-ray source 1. Increases coherence. The third grid 2 is a so-called multi-slit.

The first grid 3 has a plurality of slits 3a and an X-ray phase changing portion 3b. Each of the slits 3a and the X-ray phase changing portion 3b is formed so as to extend linearly. The slit 3a and the X-ray phase shift unit 3b is arranged in a direction perpendicular to the direction in which the slit 3a and the X-ray phase change portion 3b extends in a predetermined cycle (pitch) d _1. The first grid 3 is a so-called phase grid.

The first grid 3 is arranged between the X-ray source 1 and the second grid 4. The first grid 3 changes the phase of the X-rays emitted from the X-ray source 1 to cause Talbot interference. The Talbot, X-rays having a coherence, when passing through the slit is formed grid, the distance from the grid of a predetermined (Talbot distance Z _p) apart position, without the lattice image (self-image (shown )) Is formed.

The second lattice 4 has a plurality of X-ray transmitting portions 4a and X-ray shielding portions 4b. Each of the X-ray transmitting portion 4a and the X-ray shielding portion 4b is formed so as to extend linearly. Further, the X-ray transmitting portion 4a and the X-ray shielding portion 4b are arranged with a _{predetermined period (pitch) d 2} in a direction orthogonal to the direction in which the X-ray transmitting portion 4a and the X-ray shielding portion 4b extend. The second grid 4 is a so-called absorption grid. The first grid 3, the second grid 4, and the third grid 2 are grids having different roles, but the slit 3a, the X-ray transmitting portion 4a, and the X-ray transmitting portion 2a each transmit X-rays. Further, the X-ray shielding unit 4b and the X-ray shielding unit 2b each play a role of shielding X-rays, and the X-ray phase changing unit 3b changes the phase of X-rays depending on the difference in refractive index from the slit 3a. Let me.

The second grid 4 is arranged between the first grid 3 and the detector 5, and is irradiated with X-rays that have passed through the first grid 3. The second grating 4 is disposed from the first grating 3 into the Talbot distance Z _p away. The second grid 4 interferes with the self-image of the first grid 3 to form moire fringes (not shown) on the detection surface of the detector 5.

ここで、ｄ_１は第１格子３の周期である。また、λはＸ線源１から照射されるＸ線の波長である。また、Ｒ_１は第１格子３から第２格子４までの距離である。また、ｐは任意の整数である。Moreover, the Talbot distance _{Z p} is represented by the following equation (1).

Here, d ₁ is the period of the first lattice 3. Further, λ is the wavelength of the X-ray emitted from the X-ray source 1. Further, R ₁ is the distance from the first grid 3 to the second grid 4. Further, p is an arbitrary integer.

Further, the period d ₂ of the second lattice 4 is designed to have the same period as the self-image of the first lattice 3, and is expressed by the following equation (2).

The detector 5 is configured to detect the X-rays emitted from the X-ray source 1, convert the detected X-rays into 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 is composed of a plurality of conversion elements (not shown) and pixel electrodes (not shown) arranged on the plurality of conversion elements. The detector 5 is arranged so that the arrangement directions of the pixels of the plurality of conversion elements and the pixel electrodes coincide with each other in the X direction and the Y direction at a predetermined period (pixel pitch). Further, the detector 5 is configured to output the acquired image signal to the control device 6.

The control device 6 includes a control unit 10 and an image processing unit 11. The control unit 10 is composed of a CPU (Central Processing Unit), a memory, and the like, and by executing various programs stored in the storage unit (not shown), the control unit 10 of the X-ray phase difference imaging system 100 It is configured to function as.

The image processing unit 11 is configured to generate a dark field image 32 (see FIG. 12) based on the image signal output from the detector 5. The image processing unit 11 includes, for example, a processor such as a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array) configured for image processing.

In the first embodiment, the X-ray phase difference imaging system 100 is configured to image the subject T by the fringe scanning method. In the fringe scanning method, the first grid 3 or the second grid 4 is imaged while being translated at a predetermined pitch in the X direction, and an intensity modulation signal is created and created based on the X-ray intensity detected for each pixel. This is a method of imaging based on the intensity modulation.

The subject rotation mechanism 7 (see FIG. 1) rotates the subject T around the X-ray optical axis direction (Z direction) when the subject T is imaged under the control of the control unit 10. A predetermined portion of T is extended in a direction (Y direction) in which the grids of the plurality of grids extend and in a plane (in the XY plane) orthogonal to the optical axis direction (Z direction) of X-rays (in the XY plane). It is configured to face in the direction intersecting the Y direction). Specifically, the subject rotation mechanism 7 rotates the subject T along an arc-shaped orbit when the subject T is imaged, so that the grids (third grid 2, first grid 3, and second grid) are used. It is configured to change the orientation of the subject T with respect to 4). The detailed configuration in which the subject rotation mechanism 7 rotates the subject T will be described later.

The grid position adjusting mechanism 8 is configured to adjust the relative positions of a plurality of grids among the grids under the control of the control unit 10. A detailed configuration for adjusting the relative position between the grids of a plurality of grids by the grid position adjusting mechanism 8 will be described later.

The subject position adjusting mechanism 9 is configured to hold the subject rotating mechanism 7. Further, the subject position adjusting mechanism 9 is configured to adjust the position of the subject T under the control of the control unit 10. A detailed configuration for adjusting the position of the subject T by the subject position adjusting mechanism 9 will be described later.

(Subject rotation mechanism)
Next, the configuration of the subject rotation mechanism 7 will be described with reference to FIGS. 3 to 6. As shown in FIG. 3, the subject rotation mechanism 7 includes a subject holding unit 12 for holding the subject T, an arc-shaped guide rail 13, and a rotation driving unit 14.

The subject holding portion 12 includes a subject gripping portion 12a that grips the subject T and an adjusting screw 12b. The subject grip portion 12a has a pair of grip portions that can be moved in the thickness direction (Z direction) of the subject T. The adjusting screw 12b is configured to adjust the distance between the pair of gripping portions of the subject gripping portion 12a according to the thickness (width in the Z direction) of the subject T. In the first embodiment, the subject holding portion 12 holds the subject T on the inner peripheral surface side of the arc-shaped guide rail 13.

The guide rail 13 has an arc shape and holds the subject holding portion 12 so as to be movable. Further, the guide rail 13 is provided with a rotation angle detecting unit 15 for detecting the rotation angle of the subject holding unit 12. In the first embodiment, the rotation angle detection unit 15 is provided on the guide rail 13 at positions where the rotation angles of the subject holding unit 12 are −45 degrees, 0 degrees, and 45 degrees with respect to the Y direction. ing. The rotation angle detection unit 15 is configured to detect whether or not the subject holding unit 12 is arranged at a position where the rotation angle detection unit 15 is provided. The rotation angle detection unit 15 includes, for example, a photo sensor. Further, on the outer peripheral surface side of the guide rail 13, a belt 16 having a protruding portion protruding toward the inner peripheral surface side of the guide rail 13 is provided. Both ends of the belt 16 are fixed at one end and the other end of the guide rail 13, respectively. The belt 16 is an example of the "second engaging member" in the claims.

The rotation drive unit 14 is configured to move the subject holding unit 12 in an arc shape while changing the direction of the subject holding unit 12 along the guide rail 13. The rotary drive unit 14 includes a drive source 17 (see FIG. 6), a gear 18, a first bearing 19, a second bearing 20, and a base portion 21. The gear 18 is an example of the "first engaging member" in the claims.

The drive source 17 is configured to drive the gear 18. The drive source 17 includes, for example, a stepping motor in which a gear 18 is attached to a rotating shaft. The gear 18 is engaged with the belt 16 and moves along the belt 16 by being rotated by the drive source 17. The first bearing 19 is provided on both the left and right sides (both sides in the X direction) of the gear 18, and by applying tension to the belt 16 toward the gear 18, the gear 18 runs idle with respect to the belt 16. It suppresses doing. A plurality of second bearings 20 are provided so as to sandwich the guide rail 13 from the vertical direction (Y direction).

As shown in FIG. 4, the drive source 17, the first bearing 19, and the second bearing 20 are provided on the base portion 21, respectively. Further, the rotation drive unit 14 is integrally formed with the subject holding unit 12 via the base unit 21.

The rotation range of the subject holding portion 12 is from one end side to the other end side of the guide rail 13 having a semicircle or an arc shape smaller than the semicircle. Specifically, the rotation range of the subject holding portion 12 is from one end side to the other end side of the guide rail 13 having an arc shape having a central angle θ of at least 90 degrees. Further, in the first embodiment, the subject rotation mechanism 7 is arranged so that the position of the center of curvature C of the guide rail 13 is on the optical axis of the X-ray. Further, the rotation driving unit 14 is integrally formed with the subject holding unit 12. As a result, the rotation drive unit 14 is configured to move along the guide rail 13 together with the subject holding unit 12. With this configuration, the rotation drive unit 14 moves the subject holding unit 12 along the guide rail 13 to rotate the subject T about the center of curvature C of the guide rail 13 with respect to the grid. The orientation of the subject T can be changed. As a result, even when the dark field image 32 captured by changing the rotation angle of the subject T is combined, the subject T reflected in the dark field image 32 is rotated by an angle corresponding to the rotation angle of the subject T. Can be aligned with. That is, in the subject T captured in the plurality of dark field images 32 captured by changing the rotation angle, the subject T can be aligned without performing translation other than the rotation movement.

FIG. 5 is an enlarged schematic view of the rotation drive unit 14 in FIG. As shown in FIG. 5, the gear 18 is engaged with the protrusion of the belt 16. The rotation drive unit 14 is configured to rotate the gear 18 to move the gear 18 and the belt 16 relative to each other, thereby moving the subject holding unit 12 in an arc shape along the guide rail 13. The gear 18 and the belt 16 are so-called rack and pinion mechanisms. The first bearing 19 provided on the X1 direction side of the rotation drive unit 14 applies tension to the belt 16 from the X1 direction to the X2 direction. Further, the first bearing 19 provided on the X2 direction side of the rotation drive unit 14 applies tension to the belt 16 from the X2 direction to the X1 direction.

FIG. 6 is a schematic view of the subject rotation mechanism 7 as viewed from the X direction. In FIG. 6, for convenience, the guide rail 13 is shown in a cross-sectional view.

As shown in FIG. 6, the guide rail 13 has an H-shaped cross section and has a protruding portion 13a protruding in the Y direction. In the example shown in FIG. 6, the guide rail 13 has protrusions 13a on the Z1 side and the Z2 side, respectively.

Further, the second bearing 20 is formed so that the central portion has a concave shape in the axial direction. The second bearing 20 is arranged so as to come into contact with the protruding portion 13a of the guide rail 13 at the recessed portion 20a. Specifically, the lower (Y2 direction) recessed portion 20a of the second bearing 20 provided on the upper side (Y1 direction side) is formed on the protruding portion 13a of the guide rail 13 protruding upward (Y1 direction side). On the other hand, it is in contact from the upper side (Y1 direction side). The recessed portion 20a on the upper side (Y1 direction side) of the second bearing 20 provided on the lower side (Y2 direction side) is relative to the protruding portion 13a of the guide rail 13 protruding downward (Y2 direction side). It is in contact from the lower side (Y2 direction side). By arranging the second bearing 20 in this way, it is possible to suppress the misalignment when the subject holding portion 12 and the rotation driving portion 14 move along the guide rail 13.

Further, the base portion 21 includes a drive base portion 21a for holding the rotation drive portion 14 and a subject holding base portion 21b for holding the subject holding portion 12. The drive base portion 21a has a shape extending in the Y direction, and holds the drive source 17, the first bearing 19, and the second bearing 20 on the Z2 side. Further, the subject holding base portion 21b has a shape extending in the Z direction, and holds the subject holding portion 12 on the Y1 side.

Further, the subject holding portion 12 is configured to hold the subject T by adjusting the distance between the pair of gripping portions (distance in the thickness direction of the subject T) in the subject gripping portion 12a with the adjusting screw 12b. There is. Further, the subject rotation mechanism 7 is held by the subject rotation mechanism holding unit 22. The subject rotation mechanism holding portion 22 has a guide rail holding portion 22a for holding the guide rail 13 and a guide rail holding base portion 22b for holding the guide rail holding portion 22a. It is arranged in the subject position adjusting mechanism 9 via 22b.

(Lattice position adjustment mechanism and subject position adjustment mechanism)
Next, with reference to FIG. 7, the grid position adjusting mechanism 8 of the X-ray phase difference imaging system 100 according to the first embodiment adjusts the grid position, and the subject position adjusting mechanism 9 adjusts the position of the subject T. The configuration to be adjusted will be described. Here, the Talbot-Lau interferometer, such as X-ray phase imaging system 100, to place the second grid 4 from the first grating 3 into the Talbot distance Z _p away. Further, when the relative positions of the first grid 3 and the second grid 4 are deviated, unintended moire fringes occur, which causes problems such as deterioration of the image quality of the generated image. Therefore, in the first embodiment, the X-ray phase difference imaging system 100 is configured to adjust the relative positions of the first grid 3, the second grid 4, and the third grid 2 in advance by the grid position adjusting mechanism 8. Has been done. The misalignments of the first grid 3, the second grid 4, and the third grid 2 are mainly the misalignment in the X direction, the misalignment in the Y direction, the misalignment in the Z direction, and the rotational direction around the Z direction axis. There is a misalignment in Rz, a misalignment in the rotation direction Rx around the central axis in the X direction, and a misalignment in the rotation direction Ry around the central axis in the Y direction.

As shown in FIG. 7, the lattice position adjusting mechanism 8 has an X direction, a Y direction, a Z direction, a rotation direction Rz around the Z direction axis, a rotation direction Rx around the center axis line in the X direction, and a center axis line in the Y direction. The lattices (third lattice 2, first lattice 3 and second lattice 4) are configured to be movable in the surrounding rotation direction Ry. Specifically, the lattice position adjusting mechanism 8 includes an X-direction linear motion mechanism 80, a Y-direction linear motion mechanism 81, a Z-direction linear motion mechanism 82, a linear motion mechanism connection unit 83, and a stage support unit drive unit 84. The stage support unit 85, the stage drive unit 86, and the stage 87 are included. The X-direction linear motion mechanism 80 is configured to be movable in the X-direction. The X-direction linear motion mechanism 80 includes, for example, a motor and the like. The Y-direction linear motion mechanism 81 is configured to be movable in the Y-direction. The Y-direction linear motion mechanism 81 includes, for example, a motor and the like. The Z-direction linear motion mechanism 82 is configured to be movable in the Z direction. The Z-direction linear motion mechanism 82 includes, for example, a motor and the like.

The grid position adjusting mechanism 8 is configured to move the grid in the X direction by the operation of the linear motion mechanism 80 in the X direction. Further, the grid position adjusting mechanism 8 is configured to move the grid in the Y direction by the operation of the Y-direction linear motion mechanism 81. Further, the grid position adjusting mechanism 8 is configured to move the grid in the Z direction by the operation of the Z-direction linear motion mechanism 82.

The stage support portion 85 supports the stage 87 from below (Y1 direction). The stage drive unit 91 is configured to reciprocate the stage 87 in the X direction. The bottom of the stage 87 is formed in a convex curved surface toward the stage support portion 85, and is configured to rotate around the central axis in the Z direction by being reciprocated in the X direction. Further, the stage support unit drive unit 84 is configured to reciprocate the stage support unit 85 in the Z direction. Further, the bottom of the stage support portion 85 is formed in a convex curved surface shape toward the linear motion mechanism connecting portion 83, and is configured to rotate around the central axis in the X direction by being reciprocated in the Z direction. Has been done. Further, the linear motion mechanism connecting portion 83 is provided in the linear motion mechanism 80 in the X direction so as to be rotatable around the central axis in the Y direction. Therefore, the grid position adjusting mechanism 8 can rotate the grid around the central axis in the Y direction.

In the first embodiment, the subject position adjusting mechanism 9 has the same configuration as the grid position adjusting mechanism 8. Therefore, the subject position adjusting mechanism 9 has the same as the lattice position adjusting mechanism 8, the rotation direction Rx around the central axis in the X direction, the Y direction, the Z direction, and the X direction, the rotation direction Ry around the central axis in the Y direction, and , The subject T can be moved in the rotation direction Rz around the central axis in the Z direction. Unlike the subject rotation mechanism 7 that changes the orientation of the subject T with respect to the grid by rotating the subject T significantly, the grid position adjustment mechanism 8 is a mechanism that adjusts a minute angle deviation in the XY plane of the grid. be. Further, the subject position adjusting mechanism 9 is a mechanism for finely adjusting the position of the subject T reflected in the dark field image 32. Therefore, the grid position adjusting mechanism 8 and the subject position adjusting mechanism 9 are configured so that the position accuracy is higher than that of the subject rotating mechanism 7. Further, the grid position adjusting mechanism 8 and the subject position adjusting mechanism 9 are configured so that the amount of rotation of the grid and the subject T is smaller than that of the subject rotating mechanism 7.

(Subject structure and orientation of the subject with respect to the grid)
Next, with reference to FIGS. 8 to 12, the structure of the subject T and the difference in the dark field image 32 caused by the difference in the orientation of the subject T with respect to the grid will be described.

As the subject T imaged by the X-ray phase difference imaging system 100, a subject T having directivity in the diffusion direction of X-rays is preferable. In the first embodiment, as an example thereof, an example in which the subject T has a plate-like shape and includes a fiber bundle 30 inside will be described. The subject T is, for example, a carbon fiber reinforced plastic (CFRP) in which carbon fibers are used as the fiber bundle 30 and resin 31 is used as the base material. The fiber bundle is a bundle of many fibers. In the example shown in FIG. 8, the subject T has a structure in which a fiber bundle 30a extending in the Y direction and a fiber bundle 30b extending in the X direction are woven together. In the example shown in FIG. 8, the fiber bundle 30a and the fiber bundle 30b are displayed separately, but they are actually the same type of carbon fibers woven (or woven) into a sheet. Further, the examples shown in FIGS. 8 to 10 are examples in which the subject T is arranged at a position of 0 degrees.

FIG. 9 is a cross-sectional view of the subject T as viewed from the X direction. As shown in FIG. 9, the fiber bundle 30a extends in the Y direction and is woven into the fiber bundle 30b. FIG. 10 is a cross-sectional view of the subject T as viewed from the Y direction. As shown in FIG. 10, the fiber bundle 30b extends in the X direction and is woven into the fiber bundle 30a. Further, as shown in FIGS. 9 and 10, the subject T has a structure in which a plurality of sheets in which a fiber bundle 30a extending in the Y direction and a fiber bundle 30b extending in the X direction are woven are laminated in the Z direction. There is. Further, the resin 31 which is the base material of the subject T (CFRP) covers the surface of the subject T. Further, the resin 31 fills the gap between the fiber bundles 30 inside the subject T.

11 and 12 are dark-field images 32 (first dark-field image 32a and second dark-field image 32b) generated by the image processing unit 11. The first dark-field image 32a and the second dark-field image 32b are examples of "phase-contrast images" in the claims, respectively.

Here, when X-rays are incident on the fiber bundle 30, the X-rays are diffused by the fiber bundle 30. Specifically, at the interface between the fiber and the resin 31 in the subject T, X-rays are refracted by the difference in the refractive index between the fiber and the resin 31. Since the fiber bundle 30 is laminated in the subject T and the fiber bundle 30 is composed of a large number of fibers, multiple refractions occur by passing through the large number of fibers, and X-rays are diffused. ..

When the diffusion direction of X-rays is orthogonal to the extending direction of the grid (Y direction) (X direction), the sensitivity of the obtained phase contrast image is improved. On the other hand, when the diffusion direction of X-rays is along the extending direction (Y direction) of the grid, the sensitivity of the obtained phase contrast image becomes poor. Therefore, depending on the orientation of the subject T with respect to the grid, a fiber bundle 30 that appears in the phase contrast image and a fiber bundle 30 that does not appear in the phase contrast image are generated. FIG. 11 is an example of a dark field image 32 in which the subject T is arranged and imaged so that the direction in which the fiber bundle 30b extends and the direction of the lattice are orthogonal to each other. As shown in FIG. 11, when the subject T is arranged so that the fiber bundle 30b extends in a direction (X direction) orthogonal to the extending direction (Y direction) of the lattice, the first dark field image 32a is generated. The fiber bundle 30b is shown in. On the other hand, since the fiber bundle 30a extends in the direction along the extending direction (Y direction) of the lattice, it does not appear in the first dark field image 32a. Therefore, as shown in FIG. 12, when the fiber bundle 30a is arranged in the X direction by changing the direction of the subject T with respect to the lattice, the obtained second dark field image 32b shows the fibers. The bundle 30a is shown, and the fiber bundle 30b is not shown. Therefore, in the first embodiment, the subject T is rotated by the subject rotation mechanism 7 to take an image a plurality of times.

(Rotation of subject)
Next, with reference to FIGS. 13 and 14, a configuration in which the subject rotation mechanism 7 in the first embodiment rotates the subject T will be described.

FIG. 13 shows an example when the subject T is rotated by −45 degrees. As shown in FIG. 13, the rotation driving unit 14 rotates the subject T by moving along the guide rail 13 together with the subject holding unit 12. In the example shown in FIG. 13, the rotation drive unit 14 rotates the subject T by −45 degrees in the direction around the optical axis of the X-ray by moving toward the end of the guide rail 13 on the X1 side. It can be imaged in the state.

FIG. 14 is a schematic view when the subject T is rotated by 45 degrees. As shown in FIG. 14, the rotation drive unit 14 moves toward the end of the guide rail 13 on the X2 side, so that the subject T is rotated by 45 degrees in the direction around the optical axis of the X-ray. Can be imaged with.

In the first embodiment, the subject rotation mechanism 7 rotates the subject T in an arc shape from one end side to the other end side of the arcuate guide rail 13 to rotate the subject T by 90 degrees from −45 degrees to 45 degrees. By rotating the subject T by a minute, it is possible to change the direction of the subject T with respect to the grid and take an image. Therefore, at least at either position, the fiber bundle 30 appears in the dark field image 32.

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

In the first embodiment, as described above, the X-ray phase difference imaging system 100 detects the X-ray source 1, the detector 5 that detects the X-rays emitted from the X-ray source 1, and the X-ray source 1. A plurality of lattices arranged between the vessel 5 and including a first lattice 3 which is irradiated with X-rays from the X-ray source 1 and a second lattice 4 which is irradiated with X-rays from the first lattice 3 and The image processing unit 11 that generates a dark field image 32 based on the signal detected by the detector 5 and the subject T by rotating the subject T around the X-ray optical axis direction when imaging the subject T. Subject rotation mechanism 7 capable of directing a predetermined portion of the And. Thereby, by rotating the subject T, the orientation of the subject T with respect to the grid can be changed without rotating the grid. As a result, since the grid is not rotated, the orientation of the subject T with respect to the grid can be changed without adjusting the positions of the plurality of grids each time the orientation of the subject T with respect to the grid is changed.

Further, in the first embodiment, as described above, the subject rotation mechanism 7 rotates the subject T along an arcuate trajectory when the subject T is imaged, so that a predetermined portion of the subject T is rotated. , The direction in which the grids of the plurality of grids extend and the direction in which the grids of the plurality of grids intersect with the extending direction in the plane orthogonal to the optical axis direction of the X-rays are configured. Thereby, for example, the rotation range can be reduced as compared with the case where the subject T is rotated along the circumferential orbit by the mechanism that covers the circumference of the subject T over one circumference. As a result, it is possible to prevent the subject rotation mechanism 7 from becoming large.

Further, in the first embodiment, as described above, the subject rotation mechanism 7 includes a subject holding portion 12 for holding the subject T, an arc-shaped guide rail 13 for holding the subject holding portion 12 in a movable manner, and a guide. A rotation driving unit 14 that moves the subject holding unit 12 in an arc shape while changing the direction of the subject holding unit 12 along the rail 13 is provided. As a result, the subject T can be easily rotated in an arc shape by moving the subject holding portion 12 along the arc-shaped guide rail 13 by the rotation driving unit 14.

Further, in the first embodiment, as described above, the rotation range of the subject holding portion 12 on the guide rail 13 has a semicircle or an arc shape smaller than the semicircle, and the rotation driving portion 14 has an arc shape. The subject holding portion 12 holding the subject T is moved on the inner peripheral surface side of the arc-shaped guide rail 13. As a result, when the guide rail 13 has a semicircular arc shape, the subject T can be rotated 180 degrees. As a result, even if the direction in which the subject T diffuses X-rays is unknown, the subject T can be arranged in a direction in which the diffusion of X-rays can be detected with high sensitivity. Further, when the guide rail 13 has an arc shape smaller than a semicircle, the subject holding portion 12 even if the portion of the subject T on the side not held by the subject holding portion 12 protrudes from the curvature circle of the guide rail 13. Is rotated to the end of the guide rail 13, and it is possible to prevent the portion of the subject that is not held by the subject holding portion 12 from coming into contact with the end of the guide rail 13 on the opposite side. As a result, the orientation of the subject T with respect to the grid can be easily changed even when the portion of the subject T on the side not held by the subject holding portion 12 protrudes from the circle of curvature of the guide rail 13.

Further, in the first embodiment, as described above, the rotation range of the subject holding portion 12 in the guide rail 13 is from one end side to the other end side of the guide rail 13 having an arc shape having a central angle θ of at least 90 degrees. be. As a result, by moving the subject holding portion 12 from one end side to the other end side of the guide rail 13, the direction of the subject T can be changed by 90 degrees, and the fine structure inside the subject T can be changed in the direction in which the grid extends (the direction in which the grid extends. It can be oriented in a direction (X direction) orthogonal to the Y direction). As a result, the subject T can be arranged in a direction in which the scattering direction of the X-rays by the subject T and the extending direction of the lattice (Y direction) are orthogonal to each other, so that a dark field image 32 with clear contrast can be obtained. can.

Further, in the first embodiment, as described above, the rotation driving unit 14 is configured to move along the guide rail 13 together with the subject holding unit 12. As a result, the subject holding unit 12 can be moved by moving the rotation driving unit 14, so that the rotation driving unit 14 does not move together with the subject holding unit 12. It is possible to simplify the configuration of the mechanism for transmitting power from 14 to the subject holding unit 12. As a result, it is possible to simplify the configuration of the mechanism for transmitting power to the subject holding unit 12, so that the configuration of the device can be simplified.

Further, in the first embodiment, as described above, the gear 18 rotatably provided on the rotary drive unit 14 and the belt 16 provided on the guide rail 13 and engaged with the gear 18 are further included and rotated. The dynamic drive unit 14 is configured to move the subject holding unit 12 in an arc shape along the guide rail 13 by rotating the gear 18 to relatively move the gear 18 and the belt 16. As a result, by rotating the gear 18, the subject holding portion 12 can be moved along the belt 16 provided on the arc-shaped guide rail 13. As a result, the device configuration can be simplified as compared with the configuration in which the subject holding unit 12 is moved by a ball screw mechanism or the like.

Further, in the first embodiment, as described above, the subject rotation mechanism 7 is arranged so that the position of the center of curvature C of the guide rail 13 is on the optical axis of the X-ray. As a result, since the position of the center of curvature C of the guide rail 13 is on the optical axis of the X-ray, even when the subject T is rotated to image a plurality of dark field images 32, they are reflected in each dark field image 32. It is possible to prevent the subject T from moving in parallel in each dark field image 32. As a result, even when the dark-field images 32 are combined, the alignment can be performed by rotating the subject T, so that the dark-field images 32 can be easily combined.

Further, in the first embodiment, as described above, the subject rotation mechanism 7 is held and the subject position adjusting mechanism 9 for adjusting the position of the subject T is further provided. As a result, the position of the subject T can be adjusted while the subject T is rotated by the subject rotation mechanism 7. As a result, the position of the subject T can be adjusted while maintaining the rotation angle of the subject T. Therefore, for example, when the subject T is enlarged and imaged, different regions of the subject T have the same magnification. Even if you want to take an image of the subject T, you can change the imaging range while maintaining the rotation angle of the subject T.

Further, in the first embodiment, as described above, the lattice position adjusting mechanism 8 for adjusting the relative position between the lattices of the plurality of lattices is further provided. Thereby, for example, even if the relative position of the lattice changes due to heat or the like, the relative position between the lattices of a plurality of lattices can be adjusted. As a result, it is possible to suppress the occurrence of unintended moire due to the change in the relative position between the grids of the plurality of grids, and it is possible to suppress the deterioration of the image quality of the dark field image 32.

Further, in the first embodiment, as described above, the plurality of grids further include a third grid 2 arranged between the X-ray source 1 and the first grid 3. As a result, the coherence of X-rays emitted from the X-ray source 1 by the third lattice 2 can be enhanced. As a result, the self-image of the first lattice 3 can be formed independently of the focal size of the X-ray source 1, so that the degree of freedom in selecting the X-ray source 1 can be improved.

[Second Embodiment]
Next, the X-ray phase difference imaging system 200 (see FIG. 15) according to the second embodiment of the present invention will be described with reference to FIGS. 4, 15 and 16. Unlike the first embodiment in which the (two-dimensional) dark field image 32 of the subject T is generated, in the second embodiment, the image pickup system 40 composed of the X-ray source 1, the detector 5, and a plurality of lattices is used. A three-dimensional image pickup rotation mechanism 50 that relatively rotates the subject rotation mechanism 7 is further provided, and the image processing unit 11 is configured to generate a three-dimensional dark field image 33 (see FIG. 16). The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The three-dimensional dark field image 33 is an example of a "three-dimensional phase contrast image" in the claims.

As shown in FIG. 15, in the X-ray phase difference imaging system 200 according to the second embodiment, an imaging system 40 composed of an X-ray source 1, a detector 5, and a plurality of lattices and a subject rotation mechanism 7 are provided. A three-dimensional image pickup rotation mechanism 50 that rotates relative to a vertical axis in a plane orthogonal to the optical axis direction of X-rays is further provided. The image processing unit 11 is configured to generate a three-dimensional dark field image 33 from a plurality of dark field images 32 imaged at a plurality of rotation angles. Specifically, the three-dimensional image pickup rotation mechanism 50 rotates the subject T around the axis in the Y direction with the subject position adjusting mechanism 9, the subject rotation mechanism 7, and the subject T mounted on the mounting surface. The subject T and the imaging system 40 are configured to rotate relative to each other. The three-dimensional imaging rotation mechanism 50 includes, for example, a rotation stage.

In the second embodiment, the subject holding portion 12 is configured to hold the subject T at a position closer to the center of curvature C of the guide rail 13 than the line segment EL connecting both ends of the guide rail 13. Specifically, as shown in FIG. 4, the subject holding unit 12 has a height at which the subject holding unit 12 holds the subject T (position in the Y direction in which the subject holding unit 12a holds the subject T). The position of the broken line Hp representing the above is configured to hold the subject T at a position closer to the center of curvature C of the guide rail 13 than the line segment EL connecting both ends of the guide rail 13. Further, the imaging range of the subject T is set above the broken line Hp (direction closer to the center of curvature C (Y1 direction)).

Further, the guide rail 13 has a central angle θ of the guide rail 13 that is substantially equal on both sides of the X-ray optical axis direction with reference to the AR direction (Y direction) of the relative rotation by the three-dimensional imaging rotation mechanism 50. It is formed to be. In the example shown in FIG. 4, the guide rail 13 is formed so that the angle θ1 and the angle θ2 are substantially equal on both sides of the X-ray in the optical axis direction.

By taking an image while rotating the subject T by the three-dimensional image pickup rotation mechanism 50, the image processing unit 11 can generate a plurality of dark field images 32 imaged at a plurality of rotation angles while rotating the subject T. .. Further, even when the guide rail 13 images the subject T at a rotation angle along the optical axis direction of the X-ray, the subject holding portion 12 has a curvature of the guide rail 13 rather than the line segment EL connecting both ends of the guide rail 13. Since the subject T is held at a position close to the center C, it is possible to prevent the guide rail 13 from entering the imaging range.

FIG. 16 is a schematic view of the three-dimensional dark field image 33 generated by the image processing unit 11 in the second embodiment. In the second embodiment, the image processing unit 11 is configured to generate a three-dimensional dark field image 33 from a plurality of dark field images 32 imaged at a plurality of rotation angles while rotating the subject T.

By generating the three-dimensional dark field image 33, the image processing unit 11 determines the number of fiber bundles 30 in the region of interest in the subject T, the distance FD between the boundaries of the fiber bundles 30, and the surface area SA (hatching region). Area), the density of the fiber bundle 30, the weaving height H of the fiber bundle 30, the size S of the gap between the adjacent fiber bundles 30, and the like can be obtained.

The other configurations of the second embodiment are the same as those of the first embodiment.

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

In the second embodiment, as described above, the three-dimensional image pickup rotation mechanism 50 for relatively rotating the image pickup system 40 composed of the X-ray source 1, the detector 5, and the plurality of lattices and the subject rotation mechanism 7 is provided. Further provided, the image processing unit 11 is configured to generate a three-dimensional dark field image 33 from a plurality of dark field images 32 imaged at a plurality of rotation angles. Thereby, when the orientation of the subject T with respect to the grid is changed, the three-dimensional dark field image 33 can be generated without adjusting the positions of the plurality of grids.

Further, in the second embodiment, as described above, the subject holding portion 12 is configured to hold the subject T at a position closer to the center of curvature C of the guide rail 13 than both ends of the guide rail 13. As a result, it is possible to prevent both ends of the guide rail 13 from entering the imaging range. As a result, even when the image pickup system 40 and the subject T are imaged while being relatively rotated, it is possible to suppress the reflection of both ends of the guide rail 13 on the dark field image 32.

Further, in the second embodiment, as described above, the guide rail 13 has the central angle θ of the guide rail 13 around the optical axis direction of the X-ray with reference to the axis AR direction of the relative rotation by the three-dimensional imaging rotation mechanism 50. It is formed so that the angles are substantially equal on both sides of the. As a result, the center of the guide rail 13 and the AR direction of the relative rotation axis can be substantially coincident with each other. As a result, the guide rails 13 are formed on both sides at substantially equal angles based on the reference in the AR direction of the axis of relative rotation. Therefore, while increasing the angle of the central angle θ of the guide rails 13, both ends of the guide rails 13 have an imaging range. It can be suppressed from entering.

The other effects of the second embodiment are the same as those of the first embodiment.

(Modification example)
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims, not the description of the above-described embodiment, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims.

For example, in the first and second embodiments described above, an example including the third lattice 2 is shown, but the present invention is not limited to this. For example, when the coherence of X-rays emitted from the X-ray source 1 is high, a configuration in which the third grid 2 is not provided may be used as in the X-ray phase difference imaging system 300 shown in FIG.

Further, in the first and second embodiments, an example of a configuration in which the subject T (subject rotation mechanism 7 and subject position adjustment mechanism 9) is arranged between the first grid 3 and the second grid 4 is shown. , The present invention is not limited to this. For example, as in the X-ray phase difference imaging system 400 shown in FIG. 18, even if the subject T (subject rotation mechanism 7 and subject position adjustment mechanism 9) is arranged between the third grid 2 and the first grid 3. good. However, when the subject T is arranged between the first grid 3 and the second grid 4 and the image is taken, an image with higher image quality can be generated. Therefore, the first grid 3 and the second grid 4 It is preferable to arrange the subject T between the two.

Further, in the first and second embodiments, the subject rotation mechanism 7 has shown an example of a configuration in which the subject T is rotated by 90 degrees, but the present invention is not limited to this. The angle at which the subject rotation mechanism 7 rotates the subject T may be an angle smaller than 90 degrees. Further, the angle at which the subject rotation mechanism 7 rotates the subject T may be an angle larger than 90 degrees.

Further, in the first and second embodiments, an example of the configuration in which the belt 16 that engages with the gear 18 is provided on the guide rail 13 is shown, but the present invention is not limited to this. For example, a rack gear may be formed on the inner peripheral surface side or the outer peripheral surface side of the guide rail 13, and the rack gear and the gear 18 may be engaged with each other.

Further, in the first and second embodiments, an example of a configuration in which the rotation driving unit 14 moves along the guide rail 13 together with the subject holding unit 12 is shown, but the present invention is not limited to this. The rotation drive unit 14 does not have to move together with the subject holding unit 12. For example, the belt 16 is arranged so as to make one revolution along the guide rail 13, a part of the subject holding portion 12 is fixed to the belt 16, and a gear is provided by a drive source 17 provided in the subject rotating mechanism holding portion 22. The subject holding unit 12 may be rotated by rotating 18.

Further, in the first and second embodiments, the subject rotating mechanism 7 rotates the subject T while the belt 16 is fixed to both ends of the guide rail 13, which is an example of a configuration by a so-called rack and pinion mechanism. However, the present invention is not limited to this. For example, the belt 16 is arranged around the guide rail 13 once, and the subject T is rotated by a so-called belt and pulley mechanism in which the subject holding portion 12 is moved by rotating the gear 18 engaged with the belt 16. It may be configured to move.

Further, in the first and second embodiments, an example of a configuration in which the subject holding portion 12 is rotated by rotating the gear 18 engaged with the belt 16 is shown, but the present invention is not limited to this. For example, the configuration may not include the belt 16 and the gear 18. In the case of the configuration without the belt 16 and the gear 18, the drive source 17 may be configured to rotate the subject holding portion 12 by rotating the second bearing 20.

Further, in the first and second embodiments, an example of a configuration in which the image processing unit 11 generates a dark field image 32 as a phase contrast image is shown, but the present invention is not limited to this. For example, the image processing unit 11 may be configured to generate an absorption image and a phase differential image as a phase contrast image.

Further, in the first and second embodiments, an example of a configuration in which the subject rotation mechanism 7 is arranged so that the position of the center of curvature C of the guide rail 13 is on the optical axis of the X-ray is shown. Is not limited to this. The subject rotation mechanism 7 may be arranged so that the position of the center of curvature C of the guide rail 13 is not on the optical axis of the X-ray. However, when the subject rotation mechanism 7 is arranged so that the position of the center of curvature C of the guide rail 13 is not on the optical axis of the X-ray, each dark field image 32 is combined when a plurality of dark field images 32 are combined. Since it is necessary to translate the subject T reflected in the image, it is preferable to arrange the subject rotation mechanism 7 so that the position of the center of curvature C of the guide rail 13 is on the optical axis of the X-ray.

Further, in the first and second embodiments, the example of the configuration in which the belt 16 is provided on the outer peripheral surface side of the guide rail 13 is shown, but the present invention is not limited to this. For example, the belt 16 may be provided on the inner peripheral surface side of the guide rail 13. When the belt 16 is provided on the inner peripheral surface side of the guide rail 13, the rotary drive unit 14 may also be provided on the inner peripheral surface side of the guide rail 13.

Further, in the first and second embodiments, an example of a configuration in which a plate-shaped CFRP is imaged as a subject T is shown, but the present invention is not limited to this. The subject T may be something other than a plate shape. When the subject T has a shape other than the plate shape, the subject holding portion 12 may be configured to hold the subject T in a shape that matches the outer shape of the subject T.

Further, in the second embodiment, the center angle θ of the guide rail 13 is around the optical axis direction of the X-ray with reference to the AR direction (Y direction) of the relative rotation by the three-dimensional imaging rotation mechanism 50. Although an example of a configuration in which the angles are substantially equal on both sides of the above is shown, the present invention is not limited to this. The guide rail 13 may be formed so as to have a left-right asymmetrical shape with reference to the axis AR direction (Y direction) of the relative rotation by the three-dimensional imaging rotation mechanism 50.

Further, in the second embodiment, an example of the configuration in which the three-dimensional image pickup rotation mechanism 50 holds the subject position adjustment mechanism 9 is shown, but the present invention is not limited to this. For example, the subject position adjusting mechanism 9 may be configured to hold the three-dimensional imaging rotation mechanism 50.

Further, in the second embodiment, an example of the configuration in which the three-dimensional image pickup rotation mechanism 50 rotates the subject T (subject rotation mechanism 7 and subject position adjustment mechanism 9) is shown, but the present invention is not limited to this. .. For example, the three-dimensional image pickup rotation mechanism 50 may be configured to rotate the subject T and the image pickup system 40 relative to each other by rotating the image pickup system 40.

1 X-ray source 2 3rd grid 3 1st grid 4 2nd grid 5 Detector 7 Subject rotation mechanism 8 Grid position adjustment mechanism 9 Subject position adjustment mechanism 11 Image processing unit 12 Subject holding unit 13 Guide rail 14 Rotation drive unit 16 Belt (2nd engaging member)
18 gear (first engaging member)
32 Dark field image (phase contrast image)
32a 1st dark field image (phase contrast image)
32b Second dark field image (phase contrast image)
33 3D dark field image (3D phase contrast image)
40 Imaging system 50 Three-dimensional imaging rotation mechanism 100, 200, 300, 400 X-ray phase difference imaging system C Center of curvature Line segment connecting both ends of the EL guide rail T Subject Z direction X line optical axis direction θ Guide rail Central angle

Claims (13)

X-ray source and
A detector that detects X-rays emitted from the X-ray source, and
A plurality of grids arranged between the X-ray source and the detector and including a first grid to be irradiated with X-rays from the X-ray source and a second grid to be irradiated with X-rays from the first grid. Lattice and
An image processing unit that generates a phase contrast image based on the signal detected by the detector, and
When the subject is imaged, the subject is rotated around the optical axis direction of the X-ray along the arcuate trajectory, so that a predetermined portion of the subject is covered by the direction in which the grids of the plurality of lattices extend and the light of the X-ray. An X-ray phase difference imaging system including a subject rotation mechanism capable of directing a plurality of grids in a direction orthogonal to an axial direction and a direction in which the grids of the plurality of grids extend. The subject rotation mechanism is
The subject holding part that holds the subject and
An arc-shaped guide rail that movably holds the subject holding portion, and
The X-ray phase difference imaging system according to claim 1 , further comprising a rotation driving unit that moves the subject holding portion in an arc shape while changing the direction of the subject holding portion along the guide rail. The rotation range of the subject holding portion is from one end side to the other end side of the guide rail having a semicircle or an arc shape smaller than the semicircle.
The X-ray phase difference imaging system according to claim 2 , wherein the rotation driving unit is configured to move the subject holding unit that holds the subject on the inner peripheral surface side of the arc-shaped guide rail. The X-ray phase difference imaging system according to claim 2 , wherein the rotation range of the subject holding portion is from one end side to the other end side of the guide rail having an arc shape having a central angle of at least 90 degrees. The X-ray phase difference imaging system according to claim 2 , wherein the rotation driving unit is configured to move along the guide rail together with the subject holding unit. A first engaging member rotatably provided on the rotary drive unit and
Further including a second engaging member provided on the guide rail and engaging with the first engaging member.
The rotation driving unit rotates the first engaging member to move the first engaging member and the second engaging member relative to each other, thereby causing the subject holding portion to form a circle along the guide rail. The X-ray phase difference imaging system according to claim 5 , which is configured to move in an arc shape. The X-ray phase difference imaging system according to claim 2 , wherein the subject rotation mechanism is arranged so that the position of the center of curvature of the guide rail is on the optical axis of X-rays. The imaging system composed of the X-ray source, the detector, the plurality of lattices, and the subject rotation mechanism are relatively rotated around a vertical axis in a plane orthogonal to the optical axis direction of X-rays. Further equipped with a 3D imaging rotation mechanism,
The X-ray phase difference imaging system according to claim 2 , wherein the image processing unit is configured to generate a three-dimensional phase contrast image from a plurality of the phase contrast images captured at a plurality of rotation angles. The X-ray phase difference according to claim 8 , wherein the subject holding portion is configured to hold the subject at a position closer to the center of curvature of the guide rail than a line segment connecting both ends of the guide rail. Imaging system. The guide rail is formed so that the central angle of the guide rail is substantially equal on both sides of the X-ray optical axis direction with reference to the axial direction of relative rotation by the three-dimensional imaging rotation mechanism. The X-ray phase difference imaging system according to claim 8. The X-ray phase difference imaging system according to claim 1, further comprising a subject position adjusting mechanism that holds the subject rotating mechanism and adjusts the position of the subject. The X-ray phase difference imaging system according to claim 1, further comprising a grid position adjusting mechanism for adjusting a relative position between the plurality of grids. The X-ray phase difference imaging system according to claim 1, wherein the plurality of grids further include a third grid arranged between the X-ray source and the first grid.

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